Download Hi-Res Image 下载高分辨率图像Download to MS-PowerPoint
下载到 MS-PowerPointCite This: 引用：ACS Appl. Mater. Interfaces
ACS Appl. Mater.接口 2023, 15, 5, 6735-6746
下载到 MS-PowerPointCite This: 引用：ACS Appl. Mater. Interfaces
ACS Appl. Mater.接口 2023, 15, 5, 6735-6746
ZnO@Carbon Dot Nanoparticles Stimulating the Antibacterial Activity of Polyvinylidene Fluoride–Hexafluoropropylene with a Higher Electroactive Phase for Multifunctional Devices
ZnO@Carbon点纳米粒子刺激具有更高电活性的聚偏氟乙烯-六氟丙烯的抗菌活性，用于多功能器件
- Ping Huang 黄萍
- ,
- Shunjian Xu* 徐顺健*Shunjian Xu 徐顺建*Email: xushunjian@126.comSchool of Intelligent Manufacturing, Huzhou College, Huzhou313000, China
湖州学院智能制造学院， 湖州 313000
*电子邮件：xushunjian@126.comMore by Shunjian Xu 更多Shunjian Xu的产品 - ,
- Wei Liu 刘炜Wei Liu 刘炜School of Public Health, Xinyu University, Xinyu338004, China
新余大学公共卫生学院， 新余 338004More by Wei Liu 更多Wei Liu的产品 - ,
- Chen Liu 刘晨
- ,
- Hui Ou 欧慧
- ,
- Yongping Luo 罗永平Yongping Luo 罗永平School of Intelligent Manufacturing, Huzhou College, Huzhou313000, China
湖州学院智能制造学院， 湖州 313000More by Yongping Luo 更多Yongping Luo的产品 - ,
- Zhimin Yan 闫志敏Zhimin Yan 闫志敏School of Mechanical and Electrical Engineering, Xinyu University, Xinyu338004, China
新余大学 机电工程学院， 新余 338004More by Zhimin Yan 更多Zhimin Yan的产品 - ,
- Xu Zhou 徐周
- ,
- Pengjun Wu 吴鹏军
- , and 和
- Xingyu Liao 廖兴宇
Cite this: ACS Appl. Mater. Interfaces 2023, 15, 5, 6735–6746
引用： ACS Appl. Mater.接口2023， 15， 5， 6735–6746
引用： ACS Appl. Mater.接口2023， 15， 5， 6735–6746
Copyright © 2023 American Chemical Society
版权所有 © 2023 美国化学学会
版权所有 © 2023 美国化学学会
Your access to this publication has been provided by ZHENGZHOU UNIV LIBLearn More
Supporting Info (1)» 推荐资料 （1）»
Abstract 抽象
To further advance the application of flexible piezoelectric materials in wearable/implantable devices and robot electronic skin, it is necessary to endow them with a new function of antibacterial properties and with higher piezoelectric performance. Introducing a specially designated nanomaterial based on the nanocomposite effect is a feasible strategy to improve material properties and achieve multifunctionalization of composites. In this paper, carbon dots (CDs) were sensitized onto the surface of ZnO to form ZnO@CDs nanoparticles, which were then incorporated into polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) to obtain a multifunctional composite. On the one hand, the antibacterial property of ZnO was improved because CDs had good optical absorption of visible light and their surface functional groups were favorable for electrostatic adsorption with bacteria. Therefore, ZnO@CDs endowed the composite with an outstanding antibacterial rate of 69.1% for Staphylococcus aureus. On the other hand, CDs played a bridging role between ZnO and PVDF-HFP, reducing the negative effect of ZnO aggregation and interface incompatibility with PVDF-HFP. As a result, ZnO@CDs induced β-phase formation of 80.4% in PVDF-HFP with a d33 value of 33.8 pC N–1. The multifunctional device exhibited excellent piezoelectric and antibacterial performance in the application of energy harvesters and self-powered pressure sensors.
为了进一步推进柔性压电材料在可穿戴/植入式设备和机器人电子皮肤中的应用，有必要赋予它们抗菌性能的新功能和更高的压电性能。引入一种基于纳米复合效应的专用纳米材料是改善材料性能、实现复合材料多功能化的可行策略。本文将碳点（CDs）敏化到ZnO表面形成ZnO@CDs纳米颗粒，然后将其掺入聚偏氟乙烯-六氟丙烯（PVDF-HFP）中，得到多功能复合材料。一方面，由于CDs对可见光具有良好的光吸收性，其表面官能团有利于与细菌的静电吸附，因此提高了ZnO的抗菌性能。因此，ZnO@CDs赋予该复合材料对金黄色葡萄球菌69.1%的优异抗菌率。另一方面，CDs在ZnO和PVDF-HFP之间起到了桥接作用，减少了ZnO聚集的负面影响和与PVDF-HFP的界面不相容性。结果，ZnO@CDs在PVDF-HFP中诱导了80.4%的β相形成，d 33 值为33.8 pC N –1 。该多功能装置在能量收集器和自供电压力传感器的应用中表现出优异的压电和抗菌性能。
This publication is licensed under the terms of your
institutional subscription.
Request reuse permissions.
本出版物根据您的机构订阅条款获得许可。请求重用权限。
1. Introduction 1. 引言
Flexibility, miniaturization, multifunctionality, and low power consumption have become the general trends in the development of electronic devices. (1−4) In the “dual carbon” era, using electronic devices themselves to collect energy from their surroundings is a better way to replace traditional batteries as a power source. Researchers have proposed various energy harvesting strategies at mesoscopic, microscopic, and nanoscopic perspectives through energy conversion mechanisms such as electromagnetics, electrostatics, piezoelectrics, triboelectrics, and pyroelectrics. (5−8) Piezoelectric polymers are inherently flexible, durable and easy to process, making them promising applications in this field. Among them, polyvinylidene fluoride (PVDF) (including derivatives PVDF-TrFE and PVDF-HFP, etc.) has become an outstanding representative due to its high electromechanical coupling, good biocompatibility, and wide response range. (9−11) However, the piezoelectric properties of PVDF and its derivatives are relatively poor compared with inorganic piezoelectric materials. Specially, when these piezoelectric polymers are used in wearable/implantable devices and robot electronic skins, bacteria can easily grow around them in complex environments, which in turn affects the performance of the devices and even causes danger to life. Therefore, there is an urgent need to develop a flexible device with good piezoelectric performance and antibacterial properties.
灵活性、小型化、多功能化、低功耗已成为电子设备发展的普遍趋势。（1−4）在“双碳”时代，利用电子设备本身从周围环境收集能量是取代传统电池作为动力源的更好方式。研究人员通过电磁学、静电学、压电学、摩擦电学和热释电等能量转换机制，从介观、微观和纳米角度提出了各种能量收集策略。（5−8） 压电聚合物具有固有的柔韧性、耐用性和易于加工，使其成为该领域的有前途的应用。其中，聚偏二氟乙烯（PVDF）（包括衍生物PVDF-TrFE和PVDF-HFP等）因其机电耦合性高、生物相容性好、响应范围广而成为杰出的代表。（9−11） 然而，PVDF及其衍生物的压电性能与无机压电材料相比相对较差。特别是，当这些压电聚合物用于可穿戴/植入式设备和机器人电子皮肤时，细菌很容易在复杂环境中在它们周围生长，进而影响设备的性能，甚至对生命造成危险。因此，迫切需要开发一种具有良好压电性能和抗菌性能的柔性器件。
灵活性、小型化、多功能化、低功耗已成为电子设备发展的普遍趋势。（1−4）在“双碳”时代，利用电子设备本身从周围环境收集能量是取代传统电池作为动力源的更好方式。研究人员通过电磁学、静电学、压电学、摩擦电学和热释电等能量转换机制，从介观、微观和纳米角度提出了各种能量收集策略。（5−8） 压电聚合物具有固有的柔韧性、耐用性和易于加工，使其成为该领域的有前途的应用。其中，聚偏二氟乙烯（PVDF）（包括衍生物PVDF-TrFE和PVDF-HFP等）因其机电耦合性高、生物相容性好、响应范围广而成为杰出的代表。（9−11） 然而，PVDF及其衍生物的压电性能与无机压电材料相比相对较差。特别是，当这些压电聚合物用于可穿戴/植入式设备和机器人电子皮肤时，细菌很容易在复杂环境中在它们周围生长，进而影响设备的性能，甚至对生命造成危险。因此，迫切需要开发一种具有良好压电性能和抗菌性能的柔性器件。
Introducing a specially designated nanomaterial based on the nanocomposite effect is a feasible strategy to improve material properties and achieve multifunctionalization of composites. Numerous studies have shown that ZnO exhibits excellent antibacterial activity through the production of reactive oxygen species generation, release of Zn2+, membrane dysfunction, and internalization of nanoparticles into cells. (12−14) Moreover, the antibacterial activity of ZnO can be further improved by doping, coating inorganic or organic antibacterial agents, and adjusting the size, morphology and concentration of ZnO nanomaterials. (15−17) Meanwhile, ZnO was reported as an inorganic piezoelectric additive to be incorporated into PVDF to improve its piezoelectric properties. (18−20) In this paper, the introduction of ZnO nanoparticles will be tried to stimulate the antibacterial activity of PVDF-HFP with higher piezoelectric performance. Nevertheless, the difference between the organic–inorganic phase interface and the aggregation of nanomaterials will limit their functionality to a certain extent. The key to fabricating composite films is to resolve the incompatibility between polymers and inorganic nanoparticles. Surface modifications of inorganic nanoparticles are an effective strategy to enhance the interfacial compatibility between inorganic nanoparticles and polymer matrices. (21,22)
引入一种基于纳米复合效应的专用纳米材料是改善材料性能、实现复合材料多功能化的可行策略。大量研究表明，ZnO通过产生活性氧、释放Zn 2+ 、膜功能障碍和纳米颗粒内化到细胞中表现出优异的抗菌活性。（12−14）此外，通过掺杂、包覆无机或有机抗菌剂，以及调节ZnO纳米材料的尺寸、形貌和浓度，可以进一步提高ZnO的抗菌活性。（15−17）同时，据报道，ZnO是一种无机压电添加剂，可掺入PVDF中，以改善其压电性能。（18−20） 本文将尝试引入ZnO纳米粒子来激发具有更高压电性能的PVDF-HFP的抗菌活性。然而，有机-无机相界面和纳米材料聚集之间的差异将在一定程度上限制其功能。制造复合薄膜的关键是解决聚合物和无机纳米颗粒之间的不相容性。无机纳米颗粒的表面改性是增强无机纳米颗粒与聚合物基体界面相容性的有效策略。(21,22)
引入一种基于纳米复合效应的专用纳米材料是改善材料性能、实现复合材料多功能化的可行策略。大量研究表明，ZnO通过产生活性氧、释放Zn 2+ 、膜功能障碍和纳米颗粒内化到细胞中表现出优异的抗菌活性。（12−14）此外，通过掺杂、包覆无机或有机抗菌剂，以及调节ZnO纳米材料的尺寸、形貌和浓度，可以进一步提高ZnO的抗菌活性。（15−17）同时，据报道，ZnO是一种无机压电添加剂，可掺入PVDF中，以改善其压电性能。（18−20） 本文将尝试引入ZnO纳米粒子来激发具有更高压电性能的PVDF-HFP的抗菌活性。然而，有机-无机相界面和纳米材料聚集之间的差异将在一定程度上限制其功能。制造复合薄膜的关键是解决聚合物和无机纳米颗粒之间的不相容性。无机纳米颗粒的表面改性是增强无机纳米颗粒与聚合物基体界面相容性的有效策略。(21,22)
Our research group has even incorporated carbon dots (CDs) into PVDF-HFP to improve the piezoelectric performance. (23) CDs can be regarded as core-shell carbon nanomaterials, with amorphous or sp2-sp3 hybrid crystalline carbon cores and spherical shells rich in defects and functional groups. This shell of CDs can form hydrogen bonds with PVDF-HFP and provide a large number of inducing sites for β-phase formation in PVDF-HFP. Meanwhile, it has been reported in the literature that CDs themselves are also antimicrobial through reactive oxygen species generation and surface charges, exhibiting good stability and biocompatibility. (24,25) In this study, ZnO nanoparticles will first be decorated by sensitizing CDs through the surface carboxyl functional group of CDs to obtain ZnO@CDs nanoparticles. (26,27) Then, the prepared ZnO@CDs will be incorporated into the PVDF-HFP matrix in order to achieve better antibacterial activity and piezoelectric performance than pure ZnO. The incompatibility between polymers and inorganic nanoparticles can be well resolved by CDs as an intermediate bridge. The effect of ZnO@CDs nanoparticles on the antibacterial and piezoelectricity activities of PVDF-HFP will be comprehensively investigated to construct antibacterial piezoelectric devices.
我们的研究小组甚至在PVDF-HFP中加入了碳点（CD），以提高压电性能。（23）CDs可视为核壳碳纳米材料，具有非晶态或 2 sp-sp 3 杂化结晶碳核和富含缺陷和官能团的球壳。这种CD壳层可以与PVDF-HFP形成氢键，并为PVDF-HFP中的β相形成提供大量的诱导位点。同时，文献报道CDs本身也通过活性氧的产生和表面电荷来抗菌，表现出良好的稳定性和生物相容性。（24,25） 本研究首先通过CDs表面羧基官能团对CD进行敏化修饰，获得ZnO@CDs纳米颗粒。（26,27）然后，将制备的ZnO@CDs掺入PVDF-HFP基体中，以获得比纯ZnO更好的抗菌活性和压电性能。聚合物和无机纳米颗粒之间的不相容性可以通过CDs作为中间桥梁很好地解决。将全面研究ZnO@CDs纳米颗粒对PVDF-HFP抗菌和压电活性的影响，以构建抗菌压电器件。
我们的研究小组甚至在PVDF-HFP中加入了碳点（CD），以提高压电性能。（23）CDs可视为核壳碳纳米材料，具有非晶态或 2 sp-sp 3 杂化结晶碳核和富含缺陷和官能团的球壳。这种CD壳层可以与PVDF-HFP形成氢键，并为PVDF-HFP中的β相形成提供大量的诱导位点。同时，文献报道CDs本身也通过活性氧的产生和表面电荷来抗菌，表现出良好的稳定性和生物相容性。（24,25） 本研究首先通过CDs表面羧基官能团对CD进行敏化修饰，获得ZnO@CDs纳米颗粒。（26,27）然后，将制备的ZnO@CDs掺入PVDF-HFP基体中，以获得比纯ZnO更好的抗菌活性和压电性能。聚合物和无机纳米颗粒之间的不相容性可以通过CDs作为中间桥梁很好地解决。将全面研究ZnO@CDs纳米颗粒对PVDF-HFP抗菌和压电活性的影响，以构建抗菌压电器件。
2. Experimental Section 2. 实验部分
2.1. Materials 2.1. 材料
Citric acid, urea, zinc acetate dihydrate, potassium hydroxide, methanol, N,N-dimethyl formamide (DMF), acetone, and PVDF-HFP (Mw = 4 × 105) were supplied by Shanghai Aladdin Biochemical Technology Co., Ltd. Indium tin oxide-polyethylene naphthalate (ITO-PEN, R□ = 6 Ω/□) was purchased from Southern China Xiangcheng Technology Co., Ltd. All materials were used as received.
柠檬酸、尿素、醋酸锌二水合物、氢氧化钾、甲醇、N，N-二甲基甲酰胺（DMF）、丙酮、PVDF-HFP（M w = 4 × 10 5 ）由上海阿拉丁生化科技有限公司提供。 氧化铟锡-聚萘二甲酸乙二醇酯（ITO-PEN，R □ =6 Ω/□）购自华南相城科技有限公司。所有材料均按原样使用。
柠檬酸、尿素、醋酸锌二水合物、氢氧化钾、甲醇、N，N-二甲基甲酰胺（DMF）、丙酮、PVDF-HFP（M w = 4 × 10 5 ）由上海阿拉丁生化科技有限公司提供。 氧化铟锡-聚萘二甲酸乙二醇酯（ITO-PEN，R □ =6 Ω/□）购自华南相城科技有限公司。所有材料均按原样使用。
2.2. Synthesis of ZnO@CDs Nanoparticles
2.2. ZnO@CDs纳米粒子的合成
CDs were synthesized by the solvothermal method according to the previous report. (28,29) Briefly, citric acid (3 g), urea (6 g), and DMF (30 mL) were heated at 160 °C for 4 h and then cooled down to room temperature. The reacted solution was processed by centrifugation at 10,000 rpm for 30 min, suction-filtered with 0.22 μm membranes, and dialyzed with 1000 Da hydrolysis membrane for 24 h. The purified CDs solution was then freeze-dried into dark powder for later use. ZnO nanoparticles were prepared through the hydrolysis reaction. (30,31) In detail, 0.15 mol/L methanol solution of potassium hydroxide was added dropwise to 0.1 mol/L methanol solution of zinc acetate dihydrate, and the reaction was carried out in a constant temperature water bath at 60 °C for 1.5 h. The obtained solution was centrifuged twice at 10,000 rpm for 30 min to wash off the residue. The colloidal ZnO nanoparticles were then dispersed in 10 mL of DMF. CDs (1 mg) were added into the ZnO/DMF dispersion and then stirred magnetically for 24 h to get the ZnO@CDs/DMF dispersion.
根据上一份报告，通过溶剂热法合成了CDs。（28,29）简而言之，将柠檬酸（3g），尿素（6g）和DMF（30mL）在160°C下加热4小时，然后冷却至室温。反应溶液以10,000rpm离心处理30 min，用0.22 μm膜吸过滤，用1000 Da水解膜透析24 h。然后将纯化的CDs溶液冷冻干燥成深色粉末以备后用。通过水解反应制备了ZnO纳米颗粒。（30,31）详细地将0.15 mol/L氢氧化钾甲醇溶液滴加到0.1 mol/L二水合醋酸锌甲醇溶液中，在60 °C恒温水浴中反应1.5 h。将所得溶液以10,000rpm离心两次，持续30分钟以洗去残留物。然后将胶体 ZnO 纳米颗粒分散在 10 mL DMF 中。将CDs（1mg）加入ZnO/DMF分散体中，然后磁性搅拌24小时，得到ZnO@CDs/DMF分散体。
根据上一份报告，通过溶剂热法合成了CDs。（28,29）简而言之，将柠檬酸（3g），尿素（6g）和DMF（30mL）在160°C下加热4小时，然后冷却至室温。反应溶液以10,000rpm离心处理30 min，用0.22 μm膜吸过滤，用1000 Da水解膜透析24 h。然后将纯化的CDs溶液冷冻干燥成深色粉末以备后用。通过水解反应制备了ZnO纳米颗粒。（30,31）详细地将0.15 mol/L氢氧化钾甲醇溶液滴加到0.1 mol/L二水合醋酸锌甲醇溶液中，在60 °C恒温水浴中反应1.5 h。将所得溶液以10,000rpm离心两次，持续30分钟以洗去残留物。然后将胶体 ZnO 纳米颗粒分散在 10 mL DMF 中。将CDs（1mg）加入ZnO/DMF分散体中，然后磁性搅拌24小时，得到ZnO@CDs/DMF分散体。
2.3. Preparation of Composite Films
2.3. 复合薄膜的制备
The preparation process of the piezoelectric device is shown in Figure 1a. PVDF-HFP (2 g), acetone (7 mL), and ZnO@CDs/DMF dispersion (10 mL) were stirred magnetically for 4 h to obtain the PVDF-HFP/ZnO@CDs (labeled as P-Z-C) solution. The solution was then spin-coated on the ITO-PEN electrode (15 mm × 15 mm) at a rotating speed of 1000 rpm for 60 s. After the solvent evaporated, the obtained P-Z-C film was annealed at a temperature of 120 °C for 1 h. Simultaneously, pure PVDF-HFP, PVDF-HFP/ZnO, and PVDF-HFP/CDs films were prepared by the same method, labeled as P-0-0, P-Z-0, and P-0-C respectively.
压电器件的制备工艺如图1a所示。 将PVDF-HFP（2g）、丙酮（7mL）和ZnO@CDs/DMF分散体（10mL）磁性搅拌4小时，得到PVDF-HFP/ZnO@CDs（标记为P-Z-C）溶液。然后将溶液以1000rpm的转速旋涂在ITO-PEN电极（15 mm × 15 mm）上，持续60 s。溶剂蒸发后，将得到的P-Z-C薄膜在120°C的温度下退火1 h。同时，采用相同的方法制备了纯PVDF-HFP、PVDF-HFP/ZnO和PVDF-HFP/CDs薄膜，分别标记为P-0-0、P-Z-0和P-0-C。
压电器件的制备工艺如图1a所示。 将PVDF-HFP（2g）、丙酮（7mL）和ZnO@CDs/DMF分散体（10mL）磁性搅拌4小时，得到PVDF-HFP/ZnO@CDs（标记为P-Z-C）溶液。然后将溶液以1000rpm的转速旋涂在ITO-PEN电极（15 mm × 15 mm）上，持续60 s。溶剂蒸发后，将得到的P-Z-C薄膜在120°C的温度下退火1 h。同时，采用相同的方法制备了纯PVDF-HFP、PVDF-HFP/ZnO和PVDF-HFP/CDs薄膜，分别标记为P-0-0、P-Z-0和P-0-C。
Figure 1 图1
Figure 1. (a) Preparation process and (b) schematic diagram of the piezoelectric device.
图 1.（a）压电器件的制备过程和（b）示意图。
2.4. Assembly of the Piezoelectric Device
2.4. 压电器件的组装
The piezoelectric device was composed of a sandwich structure of the piezoelectric film attached to the bottom ITO-PEN and the top ITO-PEN electrode. The top ITO-PEN electrode (10 mm × 15 mm) was physically attached on the piezoelectric film to form an effective area of 10 mm × 10 mm, as shown in Figure 1a. The part of the piezoelectric film not covered by the top electrode was wiped with acetone to serve as a lead. The entire device was encapsulated with 3 M polyimide tape.
压电器件由附着在底部ITO-PEN和顶部ITO-PEN电极上的压电薄膜的夹层结构组成。顶部ITO-PEN电极（10 mm×15 mm）物理附着在压电薄膜上，形成10 mm×10 mm的有效面积，如图1a所示。顶部电极未覆盖的压电薄膜部分用丙酮擦拭以用作引线。整个装置用 3 M 聚酰亚胺胶带封装。
压电器件由附着在底部ITO-PEN和顶部ITO-PEN电极上的压电薄膜的夹层结构组成。顶部ITO-PEN电极（10 mm×15 mm）物理附着在压电薄膜上，形成10 mm×10 mm的有效面积，如图1a所示。顶部电极未覆盖的压电薄膜部分用丙酮擦拭以用作引线。整个装置用 3 M 聚酰亚胺胶带封装。
2.5. Characterization and Measurement
2.5. 表征和测量
The morphologies of the films and nanoparticles were observed by scanning electron microscopy (SEM, EVO MA10, Zeiss) and transmission electron microscopy (TEM, JEM-2100, JEOL), respectively. X-ray diffraction (XRD, D8 advance, Bruker), Fourier transform infrared (FT-IR, Nicolet IS50, Thermo Scientific) spectroscopy, and differential thermal analysis (DTA, STA2500, NETZSCH) were carried out to investigate the structural properties of the films. The piezoelectric performance of the devices was measured by a self-constructed electromechanical platform, including a commercial mechanical sensor (M6x1, Anhui Qisheng), a stepper motor (FSL40, Sichuan Fuyu), a charge-voltage converter (VK102, Guangdong Weijingyi), an oscilloscope (UTD7102BG, Guangdong UNI-T), and a data acquisition card (VK701H, Guangdong Weijingyi).
分别采用扫描电子显微镜（SEM、EVO MA10、Zeiss）和透射电子显微镜（TEM、JEM-2100、JEOL）观察了薄膜和纳米颗粒的形貌。采用X射线衍射（XRD、D8 advance、Bruker）、傅里叶变换红外（FT-IR、Nicolet IS50、Thermo Scientific）光谱和差热分析（DTA、STA2500、耐驰）等手段研究了薄膜的结构性能。通过自构机电平台测量器件的压电性能，该平台包括商用机械传感器（M6x1，安徽启盛）、步进电机（FSL40，四川富裕）、充电电压转换器（VK102，广东伟景易）、示波器（UTD7102BG，广东UNI-T）和数据采集卡（VK701H，广东伟景易）。
分别采用扫描电子显微镜（SEM、EVO MA10、Zeiss）和透射电子显微镜（TEM、JEM-2100、JEOL）观察了薄膜和纳米颗粒的形貌。采用X射线衍射（XRD、D8 advance、Bruker）、傅里叶变换红外（FT-IR、Nicolet IS50、Thermo Scientific）光谱和差热分析（DTA、STA2500、耐驰）等手段研究了薄膜的结构性能。通过自构机电平台测量器件的压电性能，该平台包括商用机械传感器（M6x1，安徽启盛）、步进电机（FSL40，四川富裕）、充电电压转换器（VK102，广东伟景易）、示波器（UTD7102BG，广东UNI-T）和数据采集卡（VK701H，广东伟景易）。
2.6. Antibacterial Activity
2.6. 抗菌活性
The antibacterial activity of the films was investigated against Gram-positive bacteria Staphylococcus aureus (S. aureus, Shanghai Luwei, D1417B). The nutrient broth powder (9 g, Shanghai Shengsi, 201204) was dissolved into 500 mL of distilled water to form a nutrient broth. Before S. aureus seeding, the films and nutrient broth were sterilized at 121 °C for 30 min. The films were immersed in the nutrient broth, and then, a certain amount of S. aureus was picked with an inoculation loop into it to co-culture in a constant temperature shaker at 37 °C. The absorbance of the bacterial solution at 600 nm was recorded with a spectrophotometer (TU-1901, Beijing Puxi) by the turbidimetry method as the relative value of the number of bacteria.
研究了该薄膜对革兰氏阳性菌金黄色葡萄球菌（金黄色葡萄球菌，上海鲁威，D1417B）的抑菌活性。将营养汤粉（9g，上海圣思，201204）溶于500mL蒸馏水中，形成营养汤。在金黄色葡萄球菌接种之前，将薄膜和营养肉汤在121°C下灭菌30分钟。将薄膜浸入营养液中，然后用接种环将一定量的金黄色葡萄球菌挑入其中，在37°C的恒温振荡器中共培养。 用分光光度计（TU-1901，北京浦西）用比浊法记录细菌溶液在600 nm处的吸光度，作为细菌数的相对值。
研究了该薄膜对革兰氏阳性菌金黄色葡萄球菌（金黄色葡萄球菌，上海鲁威，D1417B）的抑菌活性。将营养汤粉（9g，上海圣思，201204）溶于500mL蒸馏水中，形成营养汤。在金黄色葡萄球菌接种之前，将薄膜和营养肉汤在121°C下灭菌30分钟。将薄膜浸入营养液中，然后用接种环将一定量的金黄色葡萄球菌挑入其中，在37°C的恒温振荡器中共培养。 用分光光度计（TU-1901，北京浦西）用比浊法记录细菌溶液在600 nm处的吸光度，作为细菌数的相对值。
3. Results and Discussion
3. 结果与讨论
3.1. Morphological Characteristics of ZnO@CDs Nanoparticles and Composite Films
3.1. ZnO@CDs纳米颗粒和复合薄膜的形貌特征
The morphologies of CDs, ZnO, and ZnO@CDs are exhibited in Figure 2. It could be seen from Figure 2a–c that CDs were quasi-spherical with an average particle size of 7.9 nm. HR-TEM morphologies of CDs in Figure 2b displayed that CDs had a crystalline carbon core with lattice fringes of 0.34 and 0.21 nm, which corresponded to the (002) and (100) planes of graphite. (32,33) As presented in Figure 2d–f, each spherical ZnO nanoparticle was in a dispersed state, and the particle sizes were distributed between 5 and 12 nm with an average value of 7.6 nm. As shown in Figure 2e, the lattice fringes of 0.247 and 0.263 nm were assigned to the (002) and (100) planes of ZnO, respectively. (34,35) Different from CDs and ZnO, ZnO@CDs exhibited localized aggregation of different particles, as shown in Figure 2g. By zooming in on the HR-TEM morphology of Figure 2h, it could be observed that the ZnO nanoparticles were surrounded by several CD nanoparticles to form ZnO@CDs. Furthermore, EDS analysis of ZnO@CDs in Figure 2i confirmed that CDs were successfully decorated on the surface of ZnO. Figure S1 shows the EDS images of ZnO@CD nanoparticles, indicating that Zn and O elements were well distributed in the nanoparticles. However, the N element could not be clearly found, probably because it was less abundant in CDs. Figure S2a exhibited that ZnO nanoparticles showed some agglomeration in the dispersion solutions after 6 months, while the ZnO@CDs nanoparticles could still remain homogeneous.
CDs、ZnO和ZnO@CDs的形态如图2所示。从图2a-c可以看出，CD是准球形的，平均粒径为7.9 nm。图2b中CDs的HR-TEM形貌表明，CD具有晶格条纹为0.34和0.21 nm的结晶碳核，对应于石墨的（002）和（100）平面。（32,33） 如图2d-f所示，每个球形ZnO纳米颗粒都处于分散状态，粒径分布在5至12 nm之间，平均值为7.6 nm。如图2e所示，0.247和0.263 nm的晶格条纹分别分配给ZnO的（002）和（100）平面。（34,35）与CDs和ZnO不同，ZnO@CDs表现出不同颗粒的局部聚集，如图2g所示。通过放大图2h的HR-TEM形貌，可以观察到ZnO纳米颗粒被几个CD纳米颗粒包围形成ZnO@CDs。此外，图2i中ZnO@CDs的EDS分析证实，CD在ZnO表面被成功修饰。图S1显示了ZnO@CD纳米颗粒的EDS图像，表明Zn和O元素在纳米颗粒中分布良好。然而，N元素无法清晰地找到，可能是因为它在CD中的丰度较低。 图S2a显示，ZnO纳米颗粒在6个月后在分散液中显示出一些团聚，而ZnO@CDs纳米颗粒仍能保持均匀。
CDs、ZnO和ZnO@CDs的形态如图2所示。从图2a-c可以看出，CD是准球形的，平均粒径为7.9 nm。图2b中CDs的HR-TEM形貌表明，CD具有晶格条纹为0.34和0.21 nm的结晶碳核，对应于石墨的（002）和（100）平面。（32,33） 如图2d-f所示，每个球形ZnO纳米颗粒都处于分散状态，粒径分布在5至12 nm之间，平均值为7.6 nm。如图2e所示，0.247和0.263 nm的晶格条纹分别分配给ZnO的（002）和（100）平面。（34,35）与CDs和ZnO不同，ZnO@CDs表现出不同颗粒的局部聚集，如图2g所示。通过放大图2h的HR-TEM形貌，可以观察到ZnO纳米颗粒被几个CD纳米颗粒包围形成ZnO@CDs。此外，图2i中ZnO@CDs的EDS分析证实，CD在ZnO表面被成功修饰。图S1显示了ZnO@CD纳米颗粒的EDS图像，表明Zn和O元素在纳米颗粒中分布良好。然而，N元素无法清晰地找到，可能是因为它在CD中的丰度较低。 图S2a显示，ZnO纳米颗粒在6个月后在分散液中显示出一些团聚，而ZnO@CDs纳米颗粒仍能保持均匀。
Figure 2 图2
Figure 2. TEM images and particle size distributions of (a–c) CDs and (d–f) ZnO, TEM images, and EDS spectra of (g–i) ZnO@CDs.
图2.（a–c） CD 和 （d–f） ZnO 的 TEM 图像和粒径分布、（g–i） ZnO@CDs的 TEM 图像和 EDS 光谱。
SEM morphologies of the prepared P-0-0, P-0-C, P-Z-0, and P-Z-C films are shown in Figure 3a–d. It could be clearly observed that a large number of holes are uniformly distributed in all the films, probably due to the slow volatilization process of the solvent (especially acetone). The enlarged view of the films was a good demonstration of this reason. Because there were still some PVDF-HFP wires hanging in the film pores that were not completely flushed by the solvent gas flow, along with the direction of the airflow, the pores inside the film continued to the surface of the film, with internal holes nested in the external holes. After statistical calculation, the pore sizes of these four films were all distributed in the range of 1–4 μm. It was concluded that the addition of CDs, ZnO, and ZnO@CDs did not have much effect on the morphology of the film. Some studies (1,36,37) pointed out that introducing porosity into piezoelectric materials was an effective strategy to enhance piezoelectric performance due to a large reduction in dielectric permittivity with a relatively small reduction in the piezoelectric coefficient at this porosity level. S. aureus is a spherical bacteria with a diameter of about 1 μm. Such morphology was conducive to its entry into the film, so that the antibacterial components in the films could fully interact with bacteria. As seen from Figure S3, the prepared films appeared white under sunlight, and the thicknesses of the films were ca. 10 μm. Figure 3e,f exhibits the TEM morphologies of the prepared P-Z-0 and P-Z-C films. Compared with the ZnO dispersion solution in Figure 2d,e, the ZnO nanoparticles agglomerated in the P-Z-0 film to a certain extent, as shown in Figure 3e. Nevertheless, the ZnO@CDs nanoparticles did not change much in the PVDF-HFP matrix (Figure 3f) and still maintained the same structure compared with the ZnO@CDs dispersion solution, as shown in Figure 2g,h. In addition, there was neither solid precipitation nor a liquid stratification phenomenon in the P-Z-C solution (Figure S2b), demonstrating the excellent stability of ZnO@CDs in PVDF-HFP solutions.
制备的P-0-0、P-0-C、P-Z-0和P-Z-C薄膜的SEM形貌如图3a-d所示。可以清楚地观察到，大量的空穴均匀分布在所有薄膜中，这可能是由于溶剂（尤其是丙酮）的挥发过程缓慢。电影的放大视图很好地证明了这个原因。由于薄膜孔隙中还挂着一些未被溶剂气流完全冲洗的PVDF-HFP线材，随着气流的方向，薄膜内部的孔隙一直延伸到薄膜表面，内孔嵌套在外孔中。经过统计计算，这四种薄膜的孔径均分布在1-4 μm范围内。结论是，CDs、ZnO和ZnO@CDs的添加对薄膜的形貌没有太大影响。一些研究（1,36,37）指出，在压电材料中引入孔隙率是提高压电性能的有效策略，因为介电常数大幅降低，而压电系数在该孔隙率水平下降低相对较小。金黄色葡萄球菌是一种球形细菌，直径约为 1 μm。这种形态有利于其进入薄膜，使薄膜中的抗菌成分能够与细菌充分相互作用。从图S3可以看出，制备的薄膜在阳光下呈白色，薄膜厚度约为10μm。图3e，f显示了制备的P-Z-0和P-Z-C薄膜的TEM形貌。与图2d，e中的ZnO分散液相比，ZnO纳米颗粒在一定程度上团聚在P-Z-0薄膜中，如图3e所示。 然而，ZnO@CDs纳米颗粒在PVDF-HFP基质中没有太大变化（图3f），与ZnO@CDs分散液相比仍然保持相同的结构，如图2g，h所示。此外，P-Z-C溶液中既没有固体沉淀，也没有液体分层现象（图S2b），表明ZnO@CDs在PVDF-HFP溶液中具有优异的稳定性。
制备的P-0-0、P-0-C、P-Z-0和P-Z-C薄膜的SEM形貌如图3a-d所示。可以清楚地观察到，大量的空穴均匀分布在所有薄膜中，这可能是由于溶剂（尤其是丙酮）的挥发过程缓慢。电影的放大视图很好地证明了这个原因。由于薄膜孔隙中还挂着一些未被溶剂气流完全冲洗的PVDF-HFP线材，随着气流的方向，薄膜内部的孔隙一直延伸到薄膜表面，内孔嵌套在外孔中。经过统计计算，这四种薄膜的孔径均分布在1-4 μm范围内。结论是，CDs、ZnO和ZnO@CDs的添加对薄膜的形貌没有太大影响。一些研究（1,36,37）指出，在压电材料中引入孔隙率是提高压电性能的有效策略，因为介电常数大幅降低，而压电系数在该孔隙率水平下降低相对较小。金黄色葡萄球菌是一种球形细菌，直径约为 1 μm。这种形态有利于其进入薄膜，使薄膜中的抗菌成分能够与细菌充分相互作用。从图S3可以看出，制备的薄膜在阳光下呈白色，薄膜厚度约为10μm。图3e，f显示了制备的P-Z-0和P-Z-C薄膜的TEM形貌。与图2d，e中的ZnO分散液相比，ZnO纳米颗粒在一定程度上团聚在P-Z-0薄膜中，如图3e所示。 然而，ZnO@CDs纳米颗粒在PVDF-HFP基质中没有太大变化（图3f），与ZnO@CDs分散液相比仍然保持相同的结构，如图2g，h所示。此外，P-Z-C溶液中既没有固体沉淀，也没有液体分层现象（图S2b），表明ZnO@CDs在PVDF-HFP溶液中具有优异的稳定性。
Figure 3 图3
Figure 3. SEM images of (a, a′) P-0-0, (b, b′) P-0-C, (c, c′) P-Z-0, and (d, d′) P-Z-C films. TEM images of (e, e′) P-Z-0 and (f, f′) P-Z-C films.
图3.（a， a′） P-0-0、（b， b′） P-0-C、（c， c′） P-Z-0 和 （d， d′） P-Z-C 薄膜的 SEM 图像。（e， e′） P-Z-0 和 （f， f′） P-Z-C 薄膜的 TEM 图像。
3.2. Antibacterial Performance of Multifunctional Composite Films
3.2. 多功能复合膜的抗菌性能
The antibacterial properties of the composite films were investigated, as shown in Figure 4. The films were immersed in the bacterial culture solution and then placed in a constant temperature shaker at 37 °C. The bacteria solution cultured for the same time was tested by the turbidimetry method with a spectrophotometer to investigate the antibacterial effect of films. Generally, the absorbance of the bacterial solution at 600 nm was used as the relative value of the number of bacteria. Figure 4a shows the absorbance curves of the bacterial solutions after S. aureus were incubated for 72 h in the presence of different films. The bacterial solution without film was used as the blank control group. It could be seen that the pure PVDF-HFP films showed a little difference compared to the control group because of the piezoelectric effect under the shaking bacterial culture. However, the absorbance of the bacterial cultures in the PVDF-HFP films containing dopants reduced much. Specifically, the bacterial solution immersed with the P-Z-C film had the lowest absorbance, followed by P-Z-0 and finally P-0-C. The absorbance value at 600 nm was extracted, and the antibacterial rates (AR) of different films were calculated by eq 1.
研究了复合薄膜的抗菌性能，如图4所示。将薄膜浸入细菌培养液中，然后置于37°C的恒温振荡器中。 用分光光度计用比浊法对同时培养的菌液进行检测，以研究薄膜的抗菌效果。通常，使用细菌溶液在600nm处的吸光度作为细菌数的相对值。图4a显示了金黄色葡萄球菌在不同薄膜存在下孵育72小时后细菌溶液的吸光度曲线。以无膜细菌溶液为空白对照组。可以看出，由于振荡细菌培养下的压电效应，纯PVDF-HFP薄膜与对照组相比略有差异。然而，含有掺杂剂的PVDF-HFP薄膜中细菌培养物的吸光度降低了很多。具体而言，浸泡在P-Z-C薄膜中的细菌溶液吸光度最低，其次是P-Z-0，最后是P-0-C。提取600 nm处的吸光度值，用方程1计算不同薄膜的抗菌率（AR）。where Ac and Ae were the absorbance of the control group and the experimental group, respectively. After calculation, it was known that the antibacterial rates of P-0-0, P-0-C, P-Z-0, and P-Z-C are 2.1, 19.8, 33.5, and 69.1%, respectively (Figure 4b). This result was confirmed by the SEM image of films after being soaked in bacterial culture. As shown in Figure 5a–d, there were a large number of white spherical particles with a diameter of about 1 μm attached to the film, which were S. aureus. It was obviously observed that due to the addition of dopants, S. aureus on the composite films were greatly reduced. Moreover, the number of S. aureus on P-Z-C film was the least, followed by P-Z-0 and P-0-C. From the above analysis, it could be concluded that PVDF-HFP showed slight antibacterial performance under the piezoelectric effect, while dopants endowed the films with significantly improved antibacterial properties. The antibacterial effect of ZnO was a little better than that of CDs, but the effect of CDs-decorated ZnO was significantly enhanced than ZnO. Furthermore, the porous morphology of the films allowed S. aureus to swim freely, increasing its full contact with antibacterial components, which was beneficial to improve the antibacterial properties of the composite films.
其中A c 和A e 分别是对照组和实验组的吸光度。经过计算，已知P-0-0、P-0-C、P-Z-0和P-Z-C的抗菌率分别为2.1%、19.8%、33.5%和69.1%（图4b）。在细菌培养物中浸泡后的薄膜的SEM图像证实了这一结果。如图5a-d所示，有大量直径约1 μm的白色球形颗粒附着在薄膜上，这些颗粒是金黄色葡萄球菌。可以明显观察到，由于掺杂剂的加入，复合膜上的金黄色葡萄球菌大大减少。此外，P-Z-C薄膜上的金黄色葡萄球菌数量最少，其次是P-Z-0和P-0-C。从以上分析可以得出结论，PVDF-HFP在压电效应下表现出轻微的抗菌性能，而掺杂剂使薄膜具有显著的抗菌性能。ZnO的抑菌效果略好于CDs，但CDs修饰的ZnO效果明显增强于ZnO。此外，薄膜的多孔形貌使金黄色葡萄球菌能够自由游动，增加了其与抗菌组分的充分接触，有利于提高复合膜的抗菌性能。
研究了复合薄膜的抗菌性能，如图4所示。将薄膜浸入细菌培养液中，然后置于37°C的恒温振荡器中。 用分光光度计用比浊法对同时培养的菌液进行检测，以研究薄膜的抗菌效果。通常，使用细菌溶液在600nm处的吸光度作为细菌数的相对值。图4a显示了金黄色葡萄球菌在不同薄膜存在下孵育72小时后细菌溶液的吸光度曲线。以无膜细菌溶液为空白对照组。可以看出，由于振荡细菌培养下的压电效应，纯PVDF-HFP薄膜与对照组相比略有差异。然而，含有掺杂剂的PVDF-HFP薄膜中细菌培养物的吸光度降低了很多。具体而言，浸泡在P-Z-C薄膜中的细菌溶液吸光度最低，其次是P-Z-0，最后是P-0-C。提取600 nm处的吸光度值，用方程1计算不同薄膜的抗菌率（AR）。
(1)
其中A c 和A e 分别是对照组和实验组的吸光度。经过计算，已知P-0-0、P-0-C、P-Z-0和P-Z-C的抗菌率分别为2.1%、19.8%、33.5%和69.1%（图4b）。在细菌培养物中浸泡后的薄膜的SEM图像证实了这一结果。如图5a-d所示，有大量直径约1 μm的白色球形颗粒附着在薄膜上，这些颗粒是金黄色葡萄球菌。可以明显观察到，由于掺杂剂的加入，复合膜上的金黄色葡萄球菌大大减少。此外，P-Z-C薄膜上的金黄色葡萄球菌数量最少，其次是P-Z-0和P-0-C。从以上分析可以得出结论，PVDF-HFP在压电效应下表现出轻微的抗菌性能，而掺杂剂使薄膜具有显著的抗菌性能。ZnO的抑菌效果略好于CDs，但CDs修饰的ZnO效果明显增强于ZnO。此外，薄膜的多孔形貌使金黄色葡萄球菌能够自由游动，增加了其与抗菌组分的充分接触，有利于提高复合膜的抗菌性能。
Figure 4 图4
Figure 4. (a) Absorbance of bacterial culture, (b) antibacterial rate of different composite films at 72 h, (c) absorbance of bacterial culture, (d) antibacterial rates of P-Z-C at different times, (e) UV–vis spectra of nanoparticles (inset: enlarged view), and (f) FT-IR spectrum of CDs.
图4.（a）细菌培养物的吸光度，（b）72 h时不同复合膜的抗菌率，（c）细菌培养物的吸光度，（d）不同时间P-Z-C的抗菌率，（e）纳米颗粒的紫外-可见光谱（插图：放大图），（f）CDs的FT-IR光谱。
Figure 5 图5
Figure 5. SEM images of (a) P-0-0, (b) P-0-C, (c) P-Z-0, and (d) P-Z-C films after being soaked in bacterial culture (the white spherical particles were S. aureus), (e) schematic diagram of antibacterial composite films (including I/II/III three aspects).
图5.（a）P-0-0、（b）P-0-C、（c）P-Z-0和（d）P-Z-C薄膜浸泡在细菌培养物中（白色球形颗粒为金黄色葡萄球菌）后的SEM照片，（e）抗菌复合膜示意图（包括I/II/III.三个方面）。
In addition, the effect of the co-cultivation time of the P-Z-C film and S. aureus on the antibacterial rate was also studied. S. aureus themselves reproduced slowly before 24 h, resulting in inaccurate absorbance measurement, so the antibacterial rates were measured after 24 h. As can be seen from Figure 4c, the number of S. aureus in the control group increased exponentially, while that soaked with P-Z-C film increased much more slowly. Figure 4d shows the relationship between the antibacterial rate and co-cultivation time. With the extension of the co-culture time, the antibacterial rate of P-Z-C film gradually increased, but the growth rate gradually decreased, so that the antibacterial rate almost stabilized after 72 h at 69.1%.
此外，还研究了P-Z-C薄膜和金黄色葡萄球菌共培养时间对抗菌率的影响。金黄色葡萄球菌本身在24 h前繁殖缓慢，导致吸光度测量不准确，因此在24 h后测量抗菌率。从图4c可以看出，对照组的金黄色葡萄球菌数量呈指数级增长，而用P-Z-C薄膜浸泡的金黄色葡萄球菌数量增加得更慢。图4d显示了抗菌率与共培养时间之间的关系。随着共培养时间的延长，P-Z-C膜的抗菌率逐渐增加，但生长速率逐渐降低，使抗菌率在72 h后几乎稳定在69.1%。
此外，还研究了P-Z-C薄膜和金黄色葡萄球菌共培养时间对抗菌率的影响。金黄色葡萄球菌本身在24 h前繁殖缓慢，导致吸光度测量不准确，因此在24 h后测量抗菌率。从图4c可以看出，对照组的金黄色葡萄球菌数量呈指数级增长，而用P-Z-C薄膜浸泡的金黄色葡萄球菌数量增加得更慢。图4d显示了抗菌率与共培养时间之间的关系。随着共培养时间的延长，P-Z-C膜的抗菌率逐渐增加，但生长速率逐渐降低，使抗菌率在72 h后几乎稳定在69.1%。
As shown in Figure 5e, the reasons for ZnO@CDs endowing the composite with good antibacterial activity might include the following aspects. (I) Most researchers emphasized that the antibacterial property of ZnO was attributed to the generation of reactive oxygen species (ROS, such as ·OH, 1O2, and H2O2), which was largely determined by the optical properties of ZnO. (13,38) As exhibited in Figure 4e, the optical absorption of ZnO was mainly concentrated in the ultraviolet band with a band gap of 3.33 eV, while CDs had a large absorption of visible light, which reduced the band gap of ZnO@CDs to 3.30 eV with optical absorption extending to the visible light range. Moreover, photogenerated electrons from CDs were introduced into the conduction band of ZnO. Thus, the ability of ZnO@CDs to generate ROS was stronger than that of ZnO. (II) Other studies had pointed out that ZnO disrupted and dysfunctioned the cell membrane of bacteria by direct contact or release of Zn ions, and then internalized into the bacteria. (39,40) As presented in Figure 4f, the abundant functional groups (such as −COOH, −OH, and −NH2) on the surface of CDs made them charged, forming electrostatic adsorption with bacteria, so CDs became the gripper to capture bacteria. (III) The ordered arrangement of dipoles and the polarization of electric domains in PVDF-HFP led to the adsorption of free charges (such as ions or electrons) to the surface of the material, (9) which would undoubtedly accelerate Processes (I) and (II).
如图5e所示，ZnO@CDs赋予复合材料良好的抗菌活性的原因可能包括以下几个方面。（I）大多数研究者强调，ZnO的抗菌性能归因于活性氧（ROS，如·OH、 1 O 2 和 H 2 O 2) ，这在很大程度上取决于 ZnO 的光学性质。（13,38） 如图4e所示，ZnO的光吸收主要集中在紫外波段，带隙为3.33 eV，而CDs对可见光的吸收较大，将ZnO@CDs的带隙减小至3.30 eV，光吸收扩展到可见光范围。此外，来自CD的光生电子被引入ZnO的导带。因此，ZnO@CDs产生ROS的能力强于ZnO。（II）其他研究指出，ZnO通过直接接触或释放Zn离子破坏细菌的细胞膜并使其功能失调，然后内化到细菌中。（39,40） 如图4f所示，CD表面丰富的官能团（如-COOH、-OH和-NH 2 ）使它们带电，与细菌形成静电吸附，因此CD成为捕获细菌的抓手。（III）PVDF-HFP中偶极子的有序排列和电畴的极化导致自由电荷（如离子或电子）吸附到材料表面，（9）这无疑会加速过程（I）和（II）。
如图5e所示，ZnO@CDs赋予复合材料良好的抗菌活性的原因可能包括以下几个方面。（I）大多数研究者强调，ZnO的抗菌性能归因于活性氧（ROS，如·OH、 1 O 2 和 H 2 O 2) ，这在很大程度上取决于 ZnO 的光学性质。（13,38） 如图4e所示，ZnO的光吸收主要集中在紫外波段，带隙为3.33 eV，而CDs对可见光的吸收较大，将ZnO@CDs的带隙减小至3.30 eV，光吸收扩展到可见光范围。此外，来自CD的光生电子被引入ZnO的导带。因此，ZnO@CDs产生ROS的能力强于ZnO。（II）其他研究指出，ZnO通过直接接触或释放Zn离子破坏细菌的细胞膜并使其功能失调，然后内化到细菌中。（39,40） 如图4f所示，CD表面丰富的官能团（如-COOH、-OH和-NH 2 ）使它们带电，与细菌形成静电吸附，因此CD成为捕获细菌的抓手。（III）PVDF-HFP中偶极子的有序排列和电畴的极化导致自由电荷（如离子或电子）吸附到材料表面，（9）这无疑会加速过程（I）和（II）。
3.3. Piezoelectric Performance of Multifunctional Composite Films
3.3. 多功能复合薄膜的压电性能
In this paper, piezoelectric devices were assembled by using these composite films as piezoelectric materials, and the piezoelectric performance of these devices was tested with a self-constructed electromechanical platform. Figure 6a–d shows the real-time output voltages of the piezoelectric devices under repeating different forces. It appeared initially that as the forces increased, the voltage signals obtained by the devices also increased. To further quantify this relationship, the average values of the applied forces and the corresponding voltages were extracted to acquire the applied force–voltage curves shown in Figure 6e. It was obviously seen that there was a good linear relation between the voltage and the applied force (U = a + b × F) for these four devices with R2 > 0.99, indicating that these devices have the potential to be used as pressure sensors. The specific linear relationships of these devices are shown in Table 1. The slope of the line was defined as the sensitivity of the piezoelectric sensor (b = ΔV/ΔF, V N–1). Therefore, the sensitivities of P-0-0, P-0-C, P-Z-0, and P-Z-C sensors are 0.123, 0.144, 0.155, and 0.211 V N–1. Compared with pure PVDF, doping with CDs, ZnO, and ZnO@CDs brought 17, 26, and 72% increases in the sensitivity of the sensor, respectively.
本文以这些复合薄膜为压电材料组装了压电器件，并利用自构机电平台测试了这些器件的压电性能。图6a-d显示了压电器件在重复不同力下的实时输出电压。最初似乎随着力的增加，设备获得的电压信号也增加了。为了进一步量化这种关系，提取了施加力和相应电压的平均值，以获得图6e所示的施加力-电压曲线。很明显，这四个器件的电压和施加力（U = a + b × F）之间存在良好的线性关系，R 2 > 0.99，表明这些器件具有用作压力传感器的潜力。这些器件的具体线性关系如表1所示。线的斜率定义为压电传感器的灵敏度 （b = ΔV/ΔF， V N –1 ）。因此，P-0-0、P-0-C、P-Z-0 和 P-Z-C 传感器的灵敏度分别为 0.123、0.144、0.155 和 0.211 V N –1 。与纯PVDF相比，CDs、ZnO和ZnO@CDs掺杂分别使传感器的灵敏度提高了17%、26%和72%。
本文以这些复合薄膜为压电材料组装了压电器件，并利用自构机电平台测试了这些器件的压电性能。图6a-d显示了压电器件在重复不同力下的实时输出电压。最初似乎随着力的增加，设备获得的电压信号也增加了。为了进一步量化这种关系，提取了施加力和相应电压的平均值，以获得图6e所示的施加力-电压曲线。很明显，这四个器件的电压和施加力（U = a + b × F）之间存在良好的线性关系，R 2 > 0.99，表明这些器件具有用作压力传感器的潜力。这些器件的具体线性关系如表1所示。线的斜率定义为压电传感器的灵敏度 （b = ΔV/ΔF， V N –1 ）。因此，P-0-0、P-0-C、P-Z-0 和 P-Z-C 传感器的灵敏度分别为 0.123、0.144、0.155 和 0.211 V N –1 。与纯PVDF相比，CDs、ZnO和ZnO@CDs掺杂分别使传感器的灵敏度提高了17%、26%和72%。
Figure 6 图6
Figure 6. Real-time output voltages of (a) P-0-0, (b) P-0-C, (c) P-Z-0, (d) P-Z-C devices under repeating different forces, and (e) applied force–voltage curves of devices (inset: photograph of the device), (f) stability of the P-Z-C device.
图6.（a） P-0-0、（b） P-0-C、（c） P-Z-0、（d） P-Z-C 器件在重复不同力下的实时输出电压，以及 （e） 器件的外施加力-电压曲线（插图：器件照片），（f） P-Z-C 器件的稳定性。
Table 1. Linear Relationships between the Open-Circuit Voltage and the Applied Force of Devices
表 1.开路电压与器件外施加力之间的线性关系
表 1.开路电压与器件外施加力之间的线性关系
| sample 样本 | a | b | R2 2 R型 |
|---|---|---|---|
| P-0-0 P-0-0型 | 0.157 | 0.123 | 0.998 |
| P-0-C P-0-C型 | 0.139 | 0.144 | 0.994 |
| P-Z-0 P-Z-0型 | 0.249 | 0.155 | 0.995 |
| P-Z-C | 0.155 | 0.211 | 0.996 |
In addition, d33 was also a physical quantity that characterized the piezoelectric properties of materials. When mechanical stress (Δσ) was applied between the opposite faces of the piezoelectric material, the charge (Q) generated across the opposite faces on a certain area (A) is given by eq 2. (41)
此外，d 33 也是表征材料压电性能的物理量。当在压电材料的相对面之间施加机械应力 （Δσ） 时，在某个区域 （A） 的相对面上产生的电荷 （Q） 由方程 2 给出。(41)
此外，d 33 也是表征材料压电性能的物理量。当在压电材料的相对面之间施加机械应力 （Δσ） 时，在某个区域 （A） 的相对面上产生的电荷 （Q） 由方程 2 给出。(41)
(2)
The voltage measured by the charge amplifier used in this study has the following conversion relationship with the surface charge of the piezoelectric material as eq 3.
本研究中使用的电荷放大器测得的电压与压电材料的表面电荷的转换关系如下，方程为3。where k = 1000 pC V–1. Combined with eq 4,
其中 k = 1000 pC V –1 .结合方程 4，where S is the pressure area, eq 5 could be obtained.
其中 S 是压力面积，可以得到方程 5。
本研究中使用的电荷放大器测得的电压与压电材料的表面电荷的转换关系如下，方程为3。
(3)
其中 k = 1000 pC V –1 .结合方程 4，
(4)
其中 S 是压力面积，可以得到方程 5。
(5)
In this study, S = 16 mm2, A = 100 mm2. Therefore, d33 values of P-0-0, P-0-C, P-Z-0, and P-Z-C were calculated as 19.7, 23.0, 24.8, and 33.8 pC N–1. The quasistatic d33 meter (ZJ-3A) was used to confirm the d33 values of the above four samples, and the results were 21.2, 23.8, 26.5, and 31.7 pC N–1, respectively. From the above data analysis, it could be concluded that ZnO@CDs doping had a good effect on the improvement of piezoelectric properties for PVDF-HFP, which was greater than that of ZnO and CDs. As seen in Figure 6f, during the repeatedly dynamic load of 3 N for more than 1000 cycles, the output voltage of the device had almost no fluctuation, revealing that the device showed sufficient electrical and mechanical stability for pressure sensing.
在这项研究中，S = 16 mm 2 ，A = 100 mm 2 。因此，P-0-0、P-0-C、P-Z-0和P-Z-C的d 33 值计算为19.7、23.0、24.8和33.8 pC N –1 。采用准静态d 33 计（ZJ-3A）对上述4个样品的d 33 值进行确认，结果分别为21.2、23.8、26.5和31.7 pC N –1 。从以上数据分析可以得出结论，ZnO@CDs掺杂对PVDF-HFP压电性能的改善效果较好，大于ZnO和CDs。如图6f所示，在3 N的重复动态负载下，超过1000个周期，该器件的输出电压几乎没有波动，这表明该器件在压力检测方面表现出足够的电气和机械稳定性。
在这项研究中，S = 16 mm 2 ，A = 100 mm 2 。因此，P-0-0、P-0-C、P-Z-0和P-Z-C的d 33 值计算为19.7、23.0、24.8和33.8 pC N –1 。采用准静态d 33 计（ZJ-3A）对上述4个样品的d 33 值进行确认，结果分别为21.2、23.8、26.5和31.7 pC N –1 。从以上数据分析可以得出结论，ZnO@CDs掺杂对PVDF-HFP压电性能的改善效果较好，大于ZnO和CDs。如图6f所示，在3 N的重复动态负载下，超过1000个周期，该器件的输出电压几乎没有波动，这表明该器件在压力检测方面表现出足够的电气和机械稳定性。
The piezoelectric performance of PVDF-HFP strongly depended on the β phase content because of its large net dipole moment from the all-trans structure, while the α phase did not exhibit piezoelectric properties. To ascertain the crystal structures of the films, XRD patterns were carried out, as shown in Figure 7a. The peak at 20.9° indicated the β phase of the (110) (200) crystal plane, while those at 18.9 and 40.2° were attributed to the α phase of (020) and (002) crystal planes. (42,43) It was noted that, compared with P-0-0 and P-0-C, there existed two other diffraction peaks at 33.8 and 36.7° in P-Z-0 and P-Z-C, which were ascribed to ZnO of (002) and (101) crystal planes, respectively. To further quantify the effect of dopants on the structural properties of the prepared films, Figure 7b illustrates the FT-IR spectra of these four piezoelectric materials. The characteristic absorption peaks at 600 and 770 cm–1 were attributed to the α phase of PVDF-HFP, while the bands at 510, 840, and 1275 cm–1 demonstrated the existence of the β phase in PVDF-HFP. (44,45) It was assumed that FT-IR absorption obeyed the Lambert–Beer law, and the relative content of the β phase in PVDF-HFP containing only α and β phases is given by eq 6. (46)
PVDF-HFP的压电性能很大程度上取决于β相含量，因为它来自全反式结构的净偶极矩，而α相没有表现出压电性能。为了确定薄膜的晶体结构，进行了XRD图谱，如图7a所示。20.9°处的峰值表示（110）（200）晶面的β相，而18.9和40.2°处的峰则归因于（020）和（002）晶面的α相。（42,43） 与P-0-0和P-0-C相比，P-Z-0和P-Z-C在33.8和36.7°处还存在另外两个衍射峰，分别归因于（002）和（101）晶面的ZnO。为了进一步量化掺杂剂对制备薄膜结构性能的影响，图7b说明了这四种压电材料的FT-IR光谱。600 和 770 cm –1 处的特征吸收峰归因于 PVDF-HFP 的α期，而 510、840 和 1275 cm –1 处的条带表明 PVDF-HFP 存在β期。（44,45） 假设傅里叶变换红外吸收遵循Lambert-Beer定律，方程6给出了仅包含α相和β相的PVDF-HFP中β相的相对含量。(46)where F(β) is the percentage of the β phase; Aα and Aβ are the absorption intensities of α and β phases, respectively; Kα and Kβ are the absorption coefficients of α and β phases, respectively. In particular, the relative absorbance at 840 and 770 cm–1, as representative peaks for β and α phases, respectively, were often used to calculate the relative percentage of electroactive phases in PVDF-HFP. The values of Kα at 770 cm–1 and Kβ at 840 cm–1 were 6.1 × 104 and 7.7 × 104 cm2 mol–1, respectively. After calculation on the basis of eq 6, F(β) of the prepared P-0-0, P-0-C, P-Z-0, and P-Z-C films are 65.7, 68.4, 76.5, and 80.4%, respectively. In conclusion, ZnO@CDs had the best induction effect of the β phase in PVDF-HFP with an enhancement of 22.4%, followed by ZnO and CDs.
其中 F（β） 是β相的百分比;A α 和A β 分别是α相和β相的吸收强度;K α 和K β 分别是α相和β相的吸收系数。特别是，分别作为β相和α相的代表峰，840和770 cm –1 处的相对吸光度通常用于计算PVDF-HFP中电活性相的相对百分比。770 cm –1 处的K值和840 cm –1 处的K β α 值分别为6.1 × 10 4 mol –1 4 和7.7 × 10 cm 2 mol。根据方程6计算，制备的P-0-0、P-0-C、P-Z-0和P-Z-C薄膜的F（β）分别为65.7%、68.4%、76.5%和80.4%。综上所述，ZnO@CDs在PVDF-HFP中β相诱导效果最好，增强了22.4%，其次是ZnO和CD。
PVDF-HFP的压电性能很大程度上取决于β相含量，因为它来自全反式结构的净偶极矩，而α相没有表现出压电性能。为了确定薄膜的晶体结构，进行了XRD图谱，如图7a所示。20.9°处的峰值表示（110）（200）晶面的β相，而18.9和40.2°处的峰则归因于（020）和（002）晶面的α相。（42,43） 与P-0-0和P-0-C相比，P-Z-0和P-Z-C在33.8和36.7°处还存在另外两个衍射峰，分别归因于（002）和（101）晶面的ZnO。为了进一步量化掺杂剂对制备薄膜结构性能的影响，图7b说明了这四种压电材料的FT-IR光谱。600 和 770 cm –1 处的特征吸收峰归因于 PVDF-HFP 的α期，而 510、840 和 1275 cm –1 处的条带表明 PVDF-HFP 存在β期。（44,45） 假设傅里叶变换红外吸收遵循Lambert-Beer定律，方程6给出了仅包含α相和β相的PVDF-HFP中β相的相对含量。(46)
(6)
其中 F（β） 是β相的百分比;A α 和A β 分别是α相和β相的吸收强度;K α 和K β 分别是α相和β相的吸收系数。特别是，分别作为β相和α相的代表峰，840和770 cm –1 处的相对吸光度通常用于计算PVDF-HFP中电活性相的相对百分比。770 cm –1 处的K值和840 cm –1 处的K β α 值分别为6.1 × 10 4 mol –1 4 和7.7 × 10 cm 2 mol。根据方程6计算，制备的P-0-0、P-0-C、P-Z-0和P-Z-C薄膜的F（β）分别为65.7%、68.4%、76.5%和80.4%。综上所述，ZnO@CDs在PVDF-HFP中β相诱导效果最好，增强了22.4%，其次是ZnO和CD。
Figure 7 图7
Figure 7. (a) XRD patterns, (b) FT-IR spectra, (c) DTA heating curves of different films (inset: partial enlarged view), and (d) d33-β phase content curve.
图7.（a）XRD图谱，（b）傅里叶变换红外光谱，（c）不同薄膜的DTA加热曲线（插图：部分放大视图），（d）d-β 33 相含量曲线。
In addition, DTA was used as a complementary technique to study the crystallization behavior of the piezoelectric materials. As exhibited from the DTA heating curves in Figure 7c, there all existed a peak near 140 °C in the melting process of these four films, which was attributed to the melting temperature of the films. Furthermore, the melting temperatures of the composite films were all higher than that of the pure film, indicating that the addition of dopants facilitated the nucleation of PVDF-HFP, thereby improving the crystallinity of PVDF-HFP. The degree of improvement is in the following order: P-0-C < P-Z-0 < P-Z-C. Besides, there was also a peak near 105 °C in the DTA cooling curves, as observed from Figure S4, which was assigned to the Curie temperature of the films. When the films started to cool from above the Curie temperature, the α phase in the PVDF-HFP would be transformed to the β phase, thus greatly increasing the β phase content of the films. It was found that the addition of dopants hardly changed the Curie temperature. Therefore, 120 °C was chosen as the annealing temperature of the films in this study, which could ensure the effective thermal polarization of the film, thereby improving the piezoelectric performance of the device.
此外，DTA作为补充技术研究了压电材料的结晶行为。从图7c的DTA加热曲线可以看出，这四种薄膜的熔化过程中都存在一个接近140°C的峰值，这归因于薄膜的熔化温度。此外，复合薄膜的熔融温度均高于纯薄膜，表明掺杂剂的加入促进了PVDF-HFP的成核，从而提高了PVDF-HFP的结晶度。改善程度依次为：P-0-C
此外，DTA作为补充技术研究了压电材料的结晶行为。从图7c的DTA加热曲线可以看出，这四种薄膜的熔化过程中都存在一个接近140°C的峰值，这归因于薄膜的熔化温度。此外，复合薄膜的熔融温度均高于纯薄膜，表明掺杂剂的加入促进了PVDF-HFP的成核，从而提高了PVDF-HFP的结晶度。改善程度依次为：P-0-C
Figure 7d shows the relation between d33 and the β phase content of composite films. The β-phase induction effect of ZnO on PVDF was much greater than that of CDs. However, due to its easy agglomeration and poor interfacial compatibility with PVDF-HFP, its d33 was not much larger than those of CDs. ZnO@CDs, on the other hand, exploited the advantages of both ZnO and CDs. Taking into account the morphological characteristics of nanoparticles and the structural properties of composite films, the improvement of piezoelectric performance for the PVDF-HFP/ZnO@CDs device was mainly due to the following reasons: (1) XRD patterns and DTA curves of the films (Figure 7a,c) demonstrated that ZnO and CDs simultaneously promoted the crystallization of PVDF-HFP, especially the induced formation of the β phase (Figure 7b), so ZnO@CDs could exert the superimposed effect of the two; (2) as shown from Figure 1b, ZnO modified with CDs effectively reduced the negative effect of ZnO aggregation and precipitation in PVDF-HFP (Figures 3 and S2), thereby ensuring the uniformity of ZnO distribution in the composites; (3) due to the abundant functional groups (such as −COOH, −OH, and −NH2) on the surface of CDs (Figure 4f), CDs played a bridging role between ZnO and PVDF-HFP, reducing the interfacial incompatibility between inorganic and organic materials, thus ensuring the synergy of the additives for the performance improvement of composites; (4) meanwhile, the hydrogen bonds formed between CQDs and PVDF-HFP dragged the PVDF-HFP chains to become straighter, and the fluorine atoms were pulled to the same side, resulting in the formation of the β phase with TTT conformation.
图7d显示了d 33 与复合薄膜β相含量之间的关系。ZnO对PVDF的β相感应效应远大于CDs。然而，由于其容易团聚和与PVDF-HFP的界面相容性差，其d 33 并不比CD大多少。 另一方面，ZnO@CDs利用了ZnO和CDs的优点。 考虑到纳米颗粒的形貌特征和复合薄膜的结构特性，PVDF-HFP/ZnO@CDs器件压电性能的提高主要归因于以下原因： （1）薄膜的XRD图谱和DTA曲线（图7a，c）表明，ZnO和CDs同时促进了PVDF-HFP的结晶，特别是诱导β相的形成（图7b），因此ZnO@CDs可以发挥两者的叠加作用;（2）如图1b所示，用CDs改性的ZnO有效降低了PVDF-HFP中ZnO聚集和析出的负面影响（图3和S2），从而保证了ZnO在复合材料中的均匀分布;（3）由于CDs表面丰富的官能团（如-COOH、-OH和-NH 2 ）（图4f），CDs在ZnO和PVDF-HFP之间起到了桥接作用，减少了无机材料与有机材料之间的界面不相容性，从而保证了添加剂的协同作用，提高了复合材料的性能;（4）同时，CQDs与PVDF-HFP之间形成的氢键拖拽PVDF-HFP链变直，氟原子被拉向同一侧，形成具有TTT构象的β相。
图7d显示了d 33 与复合薄膜β相含量之间的关系。ZnO对PVDF的β相感应效应远大于CDs。然而，由于其容易团聚和与PVDF-HFP的界面相容性差，其d 33 并不比CD大多少。 另一方面，ZnO@CDs利用了ZnO和CDs的优点。 考虑到纳米颗粒的形貌特征和复合薄膜的结构特性，PVDF-HFP/ZnO@CDs器件压电性能的提高主要归因于以下原因： （1）薄膜的XRD图谱和DTA曲线（图7a，c）表明，ZnO和CDs同时促进了PVDF-HFP的结晶，特别是诱导β相的形成（图7b），因此ZnO@CDs可以发挥两者的叠加作用;（2）如图1b所示，用CDs改性的ZnO有效降低了PVDF-HFP中ZnO聚集和析出的负面影响（图3和S2），从而保证了ZnO在复合材料中的均匀分布;（3）由于CDs表面丰富的官能团（如-COOH、-OH和-NH 2 ）（图4f），CDs在ZnO和PVDF-HFP之间起到了桥接作用，减少了无机材料与有机材料之间的界面不相容性，从而保证了添加剂的协同作用，提高了复合材料的性能;（4）同时，CQDs与PVDF-HFP之间形成的氢键拖拽PVDF-HFP链变直，氟原子被拉向同一侧，形成具有TTT构象的β相。
3.4. Applications of Multifunctional Devices
3.4. 多功能器件的应用
The application of the device may experience other forms of stress except for front-side compression, requiring corresponding flexibility and stability. Figure S5 shows photographs and corresponding real-time output voltages of the P-Z-C device under four forms of stress (pressing, peening, bending, and twisting). The device exhibited good flexibility and electrical stability under all four forms of stress, suggesting its potential for wider applications. Owing to the excellent piezoelectricity performance and antibacterial activity of the device, the following study explored the possibility of several applications for energy harvesters and self-powered pressure sensors. The device was flexible enough to be bent with the fingers, and the thickness of it was much less than that of a one-yuan coin (Figure S6). Thus, the device could be easily attached to almost any place without too much interference to its attachment.
该设备的应用可能会经历除正面压缩以外的其他形式的应力，需要相应的灵活性和稳定性。图 S5 显示了 P-Z-C 器件在四种应力形式（压、喷丸、弯曲和扭曲）下的照片和相应的实时输出电压。该器件在所有四种形式的应力下都表现出良好的柔韧性和电气稳定性，这表明其具有更广泛的应用潜力。由于该器件具有出色的压电性能和抗菌活性，以下研究探讨了能量收集器和自供电压力传感器的多种应用的可能性。该装置足够灵活，可以用手指弯曲，其厚度远小于一元硬币（图S6）。因此，该设备可以很容易地连接到几乎任何地方，而不会对其连接造成太大干扰。
该设备的应用可能会经历除正面压缩以外的其他形式的应力，需要相应的灵活性和稳定性。图 S5 显示了 P-Z-C 器件在四种应力形式（压、喷丸、弯曲和扭曲）下的照片和相应的实时输出电压。该器件在所有四种形式的应力下都表现出良好的柔韧性和电气稳定性，这表明其具有更广泛的应用潜力。由于该器件具有出色的压电性能和抗菌活性，以下研究探讨了能量收集器和自供电压力传感器的多种应用的可能性。该装置足够灵活，可以用手指弯曲，其厚度远小于一元硬币（图S6）。因此，该设备可以很容易地连接到几乎任何地方，而不会对其连接造成太大干扰。
The device could be used to capture wind energy. As shown in Figure 8a–c, when a gust of wind from the hair dryer blew through the device, the device would generate a pair of positive and negative voltage and current signals. The electrical signals would disappear at the same time when the wind stopped. Without a doubt, the value of the electrical signal generated by wind blowing was much smaller than that generated while stepping on it. Next, the piezoelectric device was connected to the green LED bulb, as presented in Figure 8d–f. When a finger hit the device surface, the device generated a voltage of more than 1.8 V, causing the LED bulb to light up momentarily. This was sufficient evidence that the mechanical energy received by the device was converted into electrical energy. If the device was attached to the surface that needed to be protected from impact, this form of application could be used to make a warning after it was touched. In addition, the device was attached to the finger joints to detect finger bending in an attempt to be applied for human–computer interactions. As exhibited in Figure 8g–i, the voltages of the device were measured at the bending angles of 10, 30, and 60°, respectively. After analysis, it was found that there was an obvious linear relationship (Y = 0.0295 + 0.0133 * X, R2 = 0.994) between the voltage of the device and the bending angle of the finger. Conversely, depending on the voltage generated by the device, the angle of joint bending could be obtained.
该设备可用于捕获风能。如图8a-c所示，当吹风机吹过设备时，设备会产生一对正负电压和电流信号。当风停止时，电信号会同时消失。毫无疑问，风吹产生的电信号值远小于踩在上面时产生的电信号值。接下来，将压电器件连接到绿色 LED 灯泡，如图 8d–f 所示。当手指撞击设备表面时，设备产生的电压超过 1.8 V，导致 LED 灯泡瞬间亮起。这足以证明该装置接收到的机械能已转化为电能。如果设备附着在需要保护免受冲击的表面上，则可以使用这种形式的应用在触摸后发出警告。此外，该设备还连接到手指关节上，以检测手指弯曲，以试图应用于人机交互。如图 8g–i 所示，分别在 10°、30° 和 60° 的弯曲角度下测量器件的电压。经过分析，发现器件的电压与手指的弯曲角度之间存在明显的线性关系（Y = 0.0295 + 0.0133 * X，R 2 = 0.994）。相反，根据设备产生的电压，可以获得接头弯曲的角度。
该设备可用于捕获风能。如图8a-c所示，当吹风机吹过设备时，设备会产生一对正负电压和电流信号。当风停止时，电信号会同时消失。毫无疑问，风吹产生的电信号值远小于踩在上面时产生的电信号值。接下来，将压电器件连接到绿色 LED 灯泡，如图 8d–f 所示。当手指撞击设备表面时，设备产生的电压超过 1.8 V，导致 LED 灯泡瞬间亮起。这足以证明该装置接收到的机械能已转化为电能。如果设备附着在需要保护免受冲击的表面上，则可以使用这种形式的应用在触摸后发出警告。此外，该设备还连接到手指关节上，以检测手指弯曲，以试图应用于人机交互。如图 8g–i 所示，分别在 10°、30° 和 60° 的弯曲角度下测量器件的电压。经过分析，发现器件的电压与手指的弯曲角度之间存在明显的线性关系（Y = 0.0295 + 0.0133 * X，R 2 = 0.994）。相反，根据设备产生的电压，可以获得接头弯曲的角度。
Figure 8 图8
Figure 8. Photographs, real-time output voltage, and current of the device under (a–c) wind blowing, (d–f) finger pressing, and (g–i) design of the finger bending detection system.
图8.（a-c）吹风、（d-f）手指按压和（g-i）手指弯曲检测系统设计下设备的照片、实时输出电压和电流。
For the case where the device is attached onto the ground tile, Figure 9a,b presents real-time output voltage and current signals of the device when stepped on. It was found that both voltage and current could be generated when walking or running over the device, suggesting that the device could harvest the impact energy that humans generated on the ground while walking or running. Voltage and current of the device during walking and running reached around 1.5 V, 20 nA and 3 V, 60 nA, respectively. The difference mainly came from the fact that the size and frequency of the force on the device during running are greater than those during walking. Specifically, Figure 9c analyzes the process of generating piezoelectric signals when the device was stepped on. The whole process was divided into three stages: (I) when the foot was treading on the device, the device generated a reverse voltage; (II) when the foot was uplifting from the device, the device generated a forward voltage; (III) when the foot was hanging, the device did not generate voltage. If the device was attached onto the ground tile of a store door and connected to an alarm, the voltage generated by the device would drive the alarm, which could remind the store owner, when a customer stepped on the device.
对于设备连接到地砖上的情况，图9a，b显示了设备踩踏时的实时输出电压和电流信号。结果发现，在设备上行走或奔跑时，电压和电流都可能产生，这表明该设备可以收集人类在行走或跑步时在地面上产生的冲击能量。在行走和跑步过程中，该器件的电压和电流分别达到 1.5 V、20 nA 和 3 V、60 nA 左右。差异主要来自于跑步过程中设备受力的大小和频率大于行走时的力。具体而言，图9c分析了器件被踩踏时产生压电信号的过程。整个过程分为三个阶段：（I）当脚踩在装置上时，装置产生反向电压;（二）当脚从装置上抬起时，装置产生正向电压;（三）脚悬空时，装置不产生电压。如果将设备连接到商店门的地砖上并连接到警报器，则设备产生的电压将驱动警报器，当顾客踩到设备时，警报器可以提醒店主。
对于设备连接到地砖上的情况，图9a，b显示了设备踩踏时的实时输出电压和电流信号。结果发现，在设备上行走或奔跑时，电压和电流都可能产生，这表明该设备可以收集人类在行走或跑步时在地面上产生的冲击能量。在行走和跑步过程中，该器件的电压和电流分别达到 1.5 V、20 nA 和 3 V、60 nA 左右。差异主要来自于跑步过程中设备受力的大小和频率大于行走时的力。具体而言，图9c分析了器件被踩踏时产生压电信号的过程。整个过程分为三个阶段：（I）当脚踩在装置上时，装置产生反向电压;（二）当脚从装置上抬起时，装置产生正向电压;（三）脚悬空时，装置不产生电压。如果将设备连接到商店门的地砖上并连接到警报器，则设备产生的电压将驱动警报器，当顾客踩到设备时，警报器可以提醒店主。
Figure 9 图9
Figure 9. Real-time output (a) voltage and (b) current of the device when stepped on, (c) generation mechanism of the device, (e) absorbance of the bacterial solution, and (f) antibacterial rates of the devices at different times.
图 9.实时输出（a）设备踩踏时的电压和（b）电流，（c）设备的产生机理，（e）细菌溶液的吸光度，以及（f）设备在不同时间的抗菌率。
In repeated use, the devices had inevitably bred bacteria. To explore the growth of bacteria in the piezoelectric films, the film was torn down from the device and put into the nutrient solution to culture for 24 h. The absorbance of the bacterial solutions at 600 nm for different service times was measured with the P-0-0 film as the control group and the P-Z-C film as the experimental group, as shown in Figure 9d. From the antibacterial rates calculated in Figure 9e, the antibacterial effect still becomes increasingly prominent with the extension of time, as shown in Figure 4d. However, the antibacterial rate of the P-Z-C film in the device served for 30 days reached the highest at 29.8%, which was significantly lower than that in the S. aureus culture. In addition, the antibacterial rate decreased when the device was used for a longer time. This was mainly because the bacteria in the environment were not a single species, and the situation was much more complicated than that in the S. aureus culture. The multifunctional film might not be able to inhibit all kinds of bacteria. The antibacterial rates of the P-0-C and P-Z-0 devices showed the same pattern as the P-Z-C device, but their effects were significantly lower than those of the P-Z-C device. In the future research, we would investigate the inhibition of the multifunctional film on different bacterial species. In any case, the piezoelectric devices showed antibacterial function in applications, which would be promising in wearable/implantable devices and robot electronic skins.
在反复使用中，这些设备不可避免地滋生了细菌。为了探索压电薄膜中细菌的生长，将薄膜从装置上撕下并放入营养液中培养24小时。以P-0-0薄膜为对照组，P-Z-C薄膜为实验组，测定细菌溶液在600 nm处不同使用时间的吸光度，如图9d所示。从图9e计算出的抗菌率来看，随着时间的延长，抗菌效果仍然越来越突出，如图4d所示。然而，30 d的器械中P-Z-C膜的抗菌率最高，为29.8%，明显低于金黄色葡萄球菌培养物。此外，当设备使用时间较长时，抗菌率会降低。这主要是因为环境中的细菌不是一个单一的物种，而且情况比金黄色葡萄球菌培养的要复杂得多。多功能薄膜可能无法抑制所有种类的细菌。P-0-C和P-Z-0装置的抗菌率与P-Z-C装置具有相同的模式，但其效果明显低于P-Z-C装置。在未来的研究中，我们将研究多功能膜对不同细菌物种的抑制作用。无论如何，压电器件在应用中显示出抗菌功能，这在可穿戴/植入式设备和机器人电子皮肤中是有希望的。
在反复使用中，这些设备不可避免地滋生了细菌。为了探索压电薄膜中细菌的生长，将薄膜从装置上撕下并放入营养液中培养24小时。以P-0-0薄膜为对照组，P-Z-C薄膜为实验组，测定细菌溶液在600 nm处不同使用时间的吸光度，如图9d所示。从图9e计算出的抗菌率来看，随着时间的延长，抗菌效果仍然越来越突出，如图4d所示。然而，30 d的器械中P-Z-C膜的抗菌率最高，为29.8%，明显低于金黄色葡萄球菌培养物。此外，当设备使用时间较长时，抗菌率会降低。这主要是因为环境中的细菌不是一个单一的物种，而且情况比金黄色葡萄球菌培养的要复杂得多。多功能薄膜可能无法抑制所有种类的细菌。P-0-C和P-Z-0装置的抗菌率与P-Z-C装置具有相同的模式，但其效果明显低于P-Z-C装置。在未来的研究中，我们将研究多功能膜对不同细菌物种的抑制作用。无论如何，压电器件在应用中显示出抗菌功能，这在可穿戴/植入式设备和机器人电子皮肤中是有希望的。
4. Conclusions 4. 结论
ZnO@CDs nanoparticles were prepared through sensitizing CDs onto the surface of ZnO and then introduced into the PVDF-HFP matrix to get the multifunctional composite PVDF-HFP/ZnO@CDs. Due to the abundant surface functional groups, CDs acted as a bridge between ZnO and PVDF-HFP, which effectively resolved the interfacial incompatibility and nanomaterial agglomeration. The β-phase content and d33 value of PVDF-HFP/ZnO@CDs reached as high as 80.4% and 33.8 pC N–1, with d33 increased by 71.6% compared with that of PVDF-HFP. Simultaneously, combining the advantages of these two antibacterial agents (ZnO, CDs), ZnO@CDs in the PVDF-HFP matrix endowed the composite with a good antibacterial rate of 69.1% for S. aureus. The device based on this multifunctional composite exhibited excellent piezoelectric and antibacterial performance in the application of energy harvesters and self-powered pressure sensors. In conclusion, ZnO@CDs nanoparticles stimulated the antibacterial activity of PVDF-HFP with higher piezoelectric performance, which would be promising in wearable/implantable devices and robot electronic skins.
通过将CD敏化到ZnO表面制备ZnO@CDs纳米颗粒，然后引入PVDF-HFP基体中，得到多功能复合PVDF-HFP/ZnO@CDs。由于表面官能团丰富，CDs充当了ZnO和PVDF-HFP之间的桥梁，有效地解决了界面不相容和纳米材料团聚的问题。PVDF-HFP/ZnO@CDs的β相含量和d 33 值分别高达80.4%和33.8 pC N –1 ，其中d 33 比PVDF-HFP提高了71.6%。同时，结合这两种抗菌剂（ZnO、CDs）的优点，PVDF-HFP基体中的ZnO@CDs赋予了该复合材料69.1%的良好抗菌率。基于这种多功能复合材料的装置在能量收集器和自供电压力传感器的应用中表现出优异的压电和抗菌性能。综上所述，ZnO@CDs纳米颗粒以更高的压电性能刺激了PVDF-HFP的抗菌活性，这在可穿戴/植入设备和机器人电子皮肤中具有前景。
通过将CD敏化到ZnO表面制备ZnO@CDs纳米颗粒，然后引入PVDF-HFP基体中，得到多功能复合PVDF-HFP/ZnO@CDs。由于表面官能团丰富，CDs充当了ZnO和PVDF-HFP之间的桥梁，有效地解决了界面不相容和纳米材料团聚的问题。PVDF-HFP/ZnO@CDs的β相含量和d 33 值分别高达80.4%和33.8 pC N –1 ，其中d 33 比PVDF-HFP提高了71.6%。同时，结合这两种抗菌剂（ZnO、CDs）的优点，PVDF-HFP基体中的ZnO@CDs赋予了该复合材料69.1%的良好抗菌率。基于这种多功能复合材料的装置在能量收集器和自供电压力传感器的应用中表现出优异的压电和抗菌性能。综上所述，ZnO@CDs纳米颗粒以更高的压电性能刺激了PVDF-HFP的抗菌活性，这在可穿戴/植入设备和机器人电子皮肤中具有前景。
Supporting Information 支持信息
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsami.2c18859.
支持信息可在 https://pubs.acs.org/doi/10.1021/acsami.2c18859 免费获得。
EDS images of ZnO@CDs nanoparticles; photographs of dispersion solutions and PVDF-HFP mixed solutions after 6 months; photograph and cross-section view of the film; DTA cooling curves of composite films; real-time output voltages of devices under different stress states; photographs of the device bent by the fingers; and comparison of the thickness of the device and one yuan coin (PDF)
ZnO@CDs纳米颗粒的EDS图像;6个月后分散液和PVDF-HFP混合溶液的照片;胶片的照片和横截面图;复合膜的DTA冷却曲线;不同应力状态下器件的实时输出电压;用手指弯曲的设备的照片;以及设备厚度与一元硬币的比较 （ PDF）
Terms & Conditions 条款及细则
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.
大多数电子支持信息文件无需订阅 ACS Web Editions 即可获得。此类文件可以按文章下载以供研究使用（如果有链接到相关文章的公共使用许可证，则该许可证可能允许其他用途）。可以通过RightsLink权限系统向ACS获得其他用途的许可：http://pubs.acs.org/page/copyright/permissions.html。
Author Information 作者信息
- Shunjian Xu - School of Intelligent Manufacturing, Huzhou College, Huzhou313000, China;
https://orcid.org/0000-0002-0130-217X;
徐顺建 - 湖州学院智能制造学院， 湖州 313000; https://orcid.org/0000-0002-0130-217X;电子邮件： xushunjian@126.com
- Ping Huang - Xinyu Institute of New Energy, Xinyu University, Xinyu338004, China;https://orcid.org/0000-0002-4642-8200
黄萍 - 新余大学新余新能源研究院， 新余 338004; https://orcid.org/0000-0002-4642-8200
Acknowledgments 确认
This research was financially supported by the Education Department of Jiangxi Province (GJJ212309; GJJ212310; GJJ212319; GJJ202320), the Natural Science Foundation of Jiangxi Province (20202BABL204023), and the Research Project of Xinyu University (XJJG-2121281), China.
这项研究得到了江西省教育厅（GJJ212309的资助;GJJ212310;GJJ212319;GJJ202320）、江西省自然科学基金（20202BABL204023）、新余大学科研项目（XJJG-2121281）。
This article references 46 other publications.
本文引用了其他 46 篇出版物。
- 1Sezer, N.; Koç, M. A Comprehensive Review on the State-of-the-Art of Piezoelectric Energy Harvesting. Nano Energy 2021, 80, 105567 DOI: 10.1016/j.nanoen.2020.105567Google Scholar Google 学术搜索1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXisVertbfI&md5=200b61a8745ceac3f0acbd997c12e5acA comprehensive review on the state-of-the-art of piezoelectric energy harvestingSezer, Nurettin; Koc, MuammerNano Energy (2021), 80 (), 105567CODEN: NEANCA; ISSN:2211-2855. (Elsevier Ltd.)A review. The global energy crisis and environmental pollutions caused mainly by the increased consumption of nonrenewable energy sources prompted researchers to explore alternative energy technologies that can harvest energies available in the ambient environment. Mech. energy is the most ubiquitous ambient energy that can be captured and converted into useful elec. power. Piezoelec. transduction is the prominent mech. energy harvesting mechanism owing to its high electromech. coupling factor and piezoelec. coeff. compared to electrostatic, electromagnetic, and triboelec. transductions. Thus, piezoelec. energy harvesting has received the utmost interest by the scientific community. Advancements of micro and nanoscale materials and manufg. processes have enabled the fabrication of piezoelec. generators with favorable features such as enhanced electromech. coupling factor, piezoelec. coeff., flexibility, stretch-ability, and integrate-ability for diverse applications. Besides that, miniature devices with lesser power demand are realized in the market with technol. developments in the electronics industry. Thus, it is anticipated that in near future, many electronics will be powered by piezoelec. generators. This paper presents a comprehensive review on the state-of-the-art of piezoelec. energy harvesting. The piezoelec. energy conversion principles are delineated, and the working mechanisms and operational modes of piezoelec. generators are elucidated. Recent researches on the developments of inorg., org., composite, and bio-inspired natural piezoelec. materials are reviewed. The applications of piezoelec. energy harvesting at nano, micro, and mesoscale in diverse fields including transportation, structures, aerial applications, in water applications, smart systems, microfluidics, biomedicals, wearable and implantable electronics, and tissue regeneration are reviewed. The advancements, limitations, and potential improvements of the materials and applications of the piezoelec. energy harvesting technol. are discussed. Briefly, this review presents the broad spectrum of piezoelec. materials for clean power supply to wireless electronics in diverse fields.
1塞泽尔，N.;Koç， M.A 关于压电能量收集最新技术的综合评论。纳米能源 2021， 80， 105567 DOI： 10.1016/j.nanoen.2020.105567 - 2Fan, F. R.; Tang, W.; Wang, Z. L. Flexible Nanogenerators for Energy Harvesting and Self-powered Electronics. Adv. Mater. 2016, 28, 4283– 4305, DOI: 10.1002/adma.201504299Google Scholar Google 学术搜索2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xlt1Wmtw%253D%253D&md5=05047adf10df5d4e87cc294c82cb1277Flexible Nanogenerators for Energy Harvesting and Self-Powered ElectronicsFan, Feng Ru; Tang, Wei; Wang, Zhong LinAdvanced Materials (Weinheim, Germany) (2016), 28 (22), 4283-4305CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Flexible nanogenerators that efficiently convert mech. energy into elec. energy have been extensively studied because of their great potential for driving low-power personal electronics and self-powered sensors. Integration of flexibility and stretchability to nanogenerator has important research significance that enables applications in flexible/stretchable electronics, org. optoelectronics, and wearable electronics. Progress in nanogenerators for mech. energy harvesting is reviewed, mainly including two key technologies: flexible piezoelec. nanogenerators (PENGs) and flexible triboelec. nanogenerators (TENGs). By means of material classification, various approaches of PENGs based on ZnO nanowires, lead zirconate titanate (PZT), poly(vinylidene fluoride) (PVDF), 2D materials, and composite materials are introduced. For flexible TENG, its structural designs and factors detg. its output performance are discussed, as well as its integration, fabrication and applications. The latest representative achievements regarding the hybrid nanogenerator are also summarized. Finally, some perspectives and challenges in this field are discussed.
2范，F.R.;唐，W.;Wang， Z. L.用于能量收集和自供电电子的柔性纳米发电机。Adv. Mater.2016， 28， 4283– 4305， DOI： 10.1002/adma.201504299 - 3Liang, S.; Xia, H. Programmable Fabrication of a Miniaturized Photodetector with Thermal Stability via Femtosecond Laser Direct writing. Opt. Lett. 2021, 46, 6075– 6078, DOI: 10.1364/OL.446556Google Scholar Google 学术搜索3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xis1eitL4%253D&md5=ac96e1591062e7b442f6bcc8d3b9bf53Programmable fabrication of a miniaturized photodetector with thermal stability via femtosecond laser direct writingLiang, Shuyu; Xia, HongOptics Letters (2021), 46 (24), 6075-6078CODEN: OPLEDP; ISSN:1539-4794. (Optica Publishing Group)With the ever-increasing sophistication of integration of electronic devices, the problem of heat accumulation has become ever more serious. Here, a miniaturized photodetector with thermal stability was fabricated by combining the excellent characteristics of femtosecond laser direct writing (FsLDW) and silicon (Si). The sensing part of the photodetector is a Si microwire composed of Si nanoparticles and the sensing area is only 300 μm2. As a result, the photodetector can work stably at a temp. as high as 100°C and the response speed of the photodetector becomes notably faster at high temps. Furthermore, an image sensor was successfully fabricated by integrating 16 photodetectors and the image sensor can also work stably at high temps. This work demonstrates the potential for application of photodetectors based on Si microwires prepd. by FsLDW under harsh conditions.
3梁，S.;Xia， H.通过飞秒激光直写实现具有热稳定性的小型化光电探测器的可编程制造.选项 Lett. 2021， 46， 6075– 6078， DOI： 10.1364/OL.446556 - 4Liang, S.; Dai, Y.; Wang, G.; Xia, H.; Zhao, J. Room-temperature Fabrication of SiC Microwire Photodetectors on Rigid and Flexible Substrates via Femtosecond Laser Direct Writing. Nanoscale 2020, 12, 23200– 23205, DOI: 10.1039/D0NR05299JGoogle Scholar Google 学术搜索4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitlWku77K&md5=ad8ac216e7c399d206c37cbc34ce0b3dRoom-temperature fabrication of SiC microwire photodetectors on rigid and flexible substrates via femtosecond laser direct writingLiang, Shuyu; Dai, Yunzhi; Wang, Gong; Xia, Hong; Zhao, JihongNanoscale (2020), 12 (45), 23200-23205CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Flexible UV photodetectors (PDs) have gained increasing demand because of their widespread applications in wearable devices. However, difficulties assocd. with complicated fabrication technologies significantly limit their scope of application. Herein, via the development of a femtosecond laser direct writing (FsLDW) strategy, silicon carbide (SiC) nanoparticles are found to be assembled in a single microwire within 30 s. The surface of the deposited SiC microwire presents a three-dimensional porous structure, which is conducive to improving the responsivity of the device. The responsivity of a SiC-based microwire PD to UV light at 365 nm is found to be 55.89 A W-1 at a 1 V bias. The as-fabricated SiC microwire PDs on a glass substrate exhibit thermal stability at 350°C, and the response speed of the PDs becomes notably faster at high temps., suggesting their promising applications in harsh conditions. Due to the low-temp. processing characteristics of this process, they can be prepd. not only on glass substrates, but also on thermosensitive polymer substrates without an extra transfer process. Moreover, the SiC microwires prepd. via FsLDW are directly deposited on the flexible substrate, and the prepd. flexible SiC-based PDs can still work stably after being bent 2000 times. This research unveils a feasible way to fabricate a PD with excellent thermal stability and mech. flexibility.
4梁，S.;戴，Y.;王，G.;夏，H.;Zhao， J.通过飞秒激光直写在刚性和柔性衬底上制造SiC微线光电探测器。纳米尺度 2020， 12， 23200– 23205， DOI： 10.1039/D0NR05299J - 5Liu, H.; Zhong, J.; Lee, C.; Lee, S. W.; Lin, L. A Comprehensive Review on Piezoelectric Energy Harvesting Technology: Materials, Mechanisms, and Applications. Appl. Phys. Rev. 2018, 5, 041306 DOI: 10.1063/1.5074184Google Scholar Google 学术搜索5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXnvVai&md5=26c2ab6e72365acaa03d962ccf29b857A comprehensive review on piezoelectric energy harvesting technology: Materials, mechanisms, and applicationsLiu, Huicong; Zhong, Junwen; Lee, Chengkuo; Lee, Seung-Wuk; Lin, LiweiApplied Physics Reviews (2018), 5 (4), 041306/1-041306/35CODEN: APRPG5; ISSN:1931-9401. (American Institute of Physics)A review. The last decade has witnessed significant advances in energy harvesting technologies as a possible alternative to provide a continuous power supply for small, low-power devices in applications, such as wireless sensing, data transmission, actuation, and medical implants. Piezoelec. energy harvesting (PEH) has been a salient topic in the literature and has attracted widespread attention from researchers due to its advantages of simple architecture, high power d., and good scalability. This paper presents a comprehensive review on the state-of-the-art of piezoelec. energy harvesting. Various key aspects to improve the overall performance of a PEH device are discussed, including basic fundamentals and configurations, materials and fabrication, performance enhancement mechanisms, applications, and future outlooks. (c) 2018 American Institute of Physics.
5刘华;钟军;李，C.;李，SW;Lin， L.A 压电能量收集技术综合综述：材料、机理和应用。应用物理修订版 2018， 5， 041306 DOI： 10.1063/1.5074184 - 6Beeby, S. P.; Tudor, M. J.; White, N. M. Energy Harvesting Vibration Sources for Microsystems Applications. Meas. Sci. Technol. 2006, 17, R175, DOI: 10.1088/0957-0233/17/12/R01Google Scholar Google 学术搜索6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlCmsrnJ&md5=7ca77117279347afd432f839b4680e59Energy harvesting vibration sources for microsystems applicationsBeeby, S. P.; Tudor, M. J.; White, N. M.Measurement Science and Technology (2006), 17 (12), R175-R195CODEN: MSTCEP; ISSN:0957-0233. (Institute of Physics Publishing)This paper reviews the state-of-the art in vibration energy harvesting for wireless, self-powered microsystems. Vibration-powered generators are typically, although not exclusively, inertial spring and mass systems. The characteristic equations for inertial-based generators are presented, along with the specific damping equations that relate to the three main transduction mechanisms employed to ext. energy from the system. These transduction mechanisms are: piezoelec., electromagnetic and electrostatic. Piezoelec. generators employ active materials that generate a charge when mech. stressed. A comprehensive review of existing piezoelec. generators is presented, including impact coupled, resonant and human-based devices. Electromagnetic generators employ electromagnetic induction arising from the relative motion between a magnetic flux gradient and a conductor. Electromagnetic generators presented in the literature are reviewed including large scale discrete devices and wafer-scale integrated versions. Electrostatic generators utilize the relative movement between elec. isolated charged capacitor plates to generate energy. The work done against the electrostatic force between the plates provides the harvested energy. Electrostatic-based generators are reviewed under the classification of in-plane overlap varying, in-plane gap closing and out-of-plane gap closing; the Coulomb force parametric generator and electret-based generators are also covered. The coupling factor of each transduction mechanism is discussed and all the devices presented in the literature are summarized in tables classified by transduction type; conclusions are drawn as to the suitability of the various techniques.
6比比，S.P.;都铎王朝，MJ;White， N. M.微系统应用的能量收集振动源。测量科学技术 2006， 17， R175， DOI： 10.1088/0957-0233/17/12/R01 - 7Zhang, Q.; Xin, C.; Shen, F.; Gong, Y.; Zi, Y.; Guo, H.; Li, Z.; Peng, Y.; Zhang, Q.; Wang, Z. L. Human Body IoT Systems Based on the Triboelectrification Effect: Energy Harvesting, Sensing, Interfacing and Communication. Energy Environ. Sci. 2022, 15, 3688, DOI: 10.1039/D2EE01590KGoogle Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XitVWksL%252FO&md5=c81fb7b622101cf8e70a6cb660174480Human body IoT systems based on the triboelectrification effect: energy harvesting, sensing, interfacing and communicationZhang, Qin; Xin, Chuanfu; Shen, Fan; Gong, Ying; Zi, YunLong; Guo, Hengyu; Li, Zhongjie; Peng, Yan; Zhang, Quan; Wang, Zhong LinEnergy & Environmental Science (2022), 15 (9), 3688-3721CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)A review. In recent years, the internet of things (IoT) has been progressing rapidly with the integration of technologies in various fields. At this stage, triboelec. nanogenerator (TENG) technol. based on the triboelectrification effect and electrostatic induction has revealed great potential in various fields, including energy harvesting and sensing. Due to the improvements of configurations and materials, TENGs offer flexibility, compatibility, and stability, enabling novel auxiliary applications by harvesting and converting human mech. energy. In this review, we first propose a concept of the TENG-based human body IoT system, consisting of energy harvesting, sensing, and interfacing, to effectively obtain, monitor and manage human motion and phys. status information. Then, we present a comprehensive overview of such an IoT system from the three aforementioned focuses. Firstly, studies on human body energy harvesting are categorized according to the configurations and materials of TENGs. Secondly, based on the high sensitivity of TENGs, wearable and implantable sensors are investigated to develop the potential of human motion or physiol. signal monitoring. Thirdly, the representative studies on TENG-based interfacing between human body and external electronics by using a microcontroller (MCU) are investigated based on various interactive types. Furthermore, we statistically discuss the developmental trend of TENGs in the above focused fields, and the materials suitable for TENGs to offer inspirational angles for future research. We also elaborate the proposed TENG-based human body IoT system by introducing various integrated modules with multi-functions. Finally, we systematically present promising prospects for future research directions and challenges from the perspectives of materials, power management, and communication. This review is dedicated to offering crit. insights into the development of TENG-based human body IoT systems.
- 8Miao, G.; Fang, S.; Wang, S.; Zhou, S. A Low-Frequency Rotational Electromagnetic Energy Harvester Using a Magnetic Plucking Mechanism. Appl. Energy 2022, 305, 117838 DOI: 10.1016/j.apenergy.2021.117838
- 9Wan, C.; Bowen, C. R. Multiscale-Structuring of Polyvinylidene Fluoride for Energy Harvesting: the Impact of Molecular-, Micro- and Macro-structure. J. Mater. Chem. A 2017, 5, 3091– 3128, DOI: 10.1039/C6TA09590AGoogle Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntlWqtw%253D%253D&md5=baef8692d6a6b47c1c111cb3be67b438Multiscale-structuring of polyvinylidene fluoride for energy harvesting: the impact of molecular-, micro- and macro-structureWan, Chaoying; Bowen, Christopher RhysJournal of Materials Chemistry A: Materials for Energy and Sustainability (2017), 5 (7), 3091-3128CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)A review is given. Energy harvesting exploits ambient sources of energy such as mech. loads, vibrations, human motion, waste heat, light or chem. sources and converts them into useful elec. energy. The applications for energy harvesting include low power electronics or wireless sensing at relatively lower power levels (nW to mW) with an aim to reduce a reliance on batteries or elec. power via cables and realize fully autonomous and self-powered systems. This paper focuses on flexible energy harvesting system based on polyvinylidene fluoride based polymers, with an emphasis on manipulating and optimizing the properties and performance of the polymeric materials and related nanocomposites through structuring the material at multiple scales. Ferroelec. properties are described and the potential of using the polarization of the materials for vibration and thermal harvesting using piezo- and pyro-elec. effects are explained. Approaches to tailor the ferroelec., piezoelec. and pyroelec. properties of polymer materials are explored in detail; these include the influence of polymer processing conditions, heat treatment, nanoconfinement, blending, forming nanocomposites and electrospinning. Examples of flexible harvesting devices that utilize the optimized ferroelec. polymer or nanocomposite systems are described and potential applications and future directions of research explored.
- 10Saxena, P.; Shukla, P. A Comprehensive Review on Fundamental Properties and Applications of Poly (vinylidene fluoride)(PVDF). Adv. Compos. Hybrid Mater. 2021, 4, 8– 26, DOI: 10.1007/s42114-021-00217-0Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtFShsL%252FL&md5=2932976766f2e2c0e19a7bcd5eba02b8A comprehensive review on fundamental properties and applications of poly(vinylidene fluoride) (PVDF)Saxena, Pooja; Shukla, PrashantAdvanced Composites and Hybrid Materials (2021), 4 (1), 8-26CODEN: ACHMCL; ISSN:2522-0136. (Springer International Publishing AG)A review. Polyvinylidene fluoride (PVDF) is known as a favorite polymer from the family of fluoropolymers due to its excellent piezoelec. properties, thermal stability, and mech. strength. It has a good processability, and it also possess chem. resistance property to different materials such as different acids, bases, org. solvents, oil, and fat. The present study reveals an overview of the recent growth and development in the application perspective and modification of PVDF membranes, majorly focus on sensors and actuators, spin-valve devices, magnetoelec. materials, energy harvesting applications, tissue engineering, modeling engineering, and other biomedical engineering and devices. From an electronic point of view, ferroelec. polymers are insulating, polar, and possess a non-conjugated backbone; therefore, they are termed as highly insulating materials. The insulating polymers are most attractive for the study of charge transportation and storage. Such polymers also yield the best electrets for practical application because of their insulating properties and high concn. of deep trapping sites. Thus, the objective of this review is to present the phys., chem., thermal, and mech. properties of PVDF. This article also provides an intelligent direction in the progress of PVDF in different fields of science and technol.
- 11Lu, L.; Ding, W.; Liu, J.; Yang, B. Flexible PVDF based Piezoelectric Nanogenerators. Nano Energy 2020, 78, 105251 DOI: 10.1016/j.nanoen.2020.105251Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhs1SrtrjI&md5=801eb5ed5b1c6c2335a65babc0b98423Flexible PVDF based piezoelectric nanogeneratorsLu, Lijun; Ding, Wenqing; Liu, Jingquan; Yang, BinNano Energy (2020), 78 (), 105251CODEN: NEANCA; ISSN:2211-2855. (Elsevier Ltd.)A review. Confronting the depletion of fossil energy and the pollution of chem. batteries, together with the rapid development of various portable electronic devices and the Internet of Things (IoT), there is an urgent requirement to develop high-performance, lightwt., and sustainable energy conversion and power supply devices. Currently, the flexible piezoelec. nanogenerator is a favorable candidate, which can be integrated with personal electronics and wireless sensors to realize sustainable energy for working with long time due to their excellent mech. properties, good environmental adaptability and outstanding energy harvesting performance. Poly(vinylidene fluoride) (PVDF) and its copolymers, as the most flexible piezoelec. polymer materials, have been widely concerned and become the research hotspot because of their excellent flexibility, strength, easy processing and low cost. To date, significant progress has been made for PVDF based nanogenerators considering improving the output performance to meet the requirement of adapting to complex vibration environments (in vivo or in vitro). Hence, a crit. review is presented to systematically summary the recent advance of flexible PVDF based piezoelec. nanogenerators in the aspects of incorporating various nanofillers, structural design, optimizing fabrication techniques and energy harvesting application. Finally, some existing challenges and future perspectives are outlined and discussed to facilitate the development of flexible piezoelec. PVDF based nanogenerators. It is hoped that this review can help researchers to gain a better overall understanding of this field and push forward it to a new stage.
- 12Abebe, B.; Zereffa, E. A.; Tadesse, A.; Murthy, H. C. A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation. Nanoscale Res. Lett. 2020, 15, 190, DOI: 10.1186/s11671-020-03418-6Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhvFOntbbL&md5=90ddf528201ba1736fed0574f7d66f2bA Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic InvestigationAbebe, Buzuayehu; Zereffa, Enyew Amare; Tadesse, Aschalew; Murthy, H. C. AnandaNanoscale Research Letters (2020), 15 (1), 190CODEN: NRLAAD; ISSN:1556-276X. (Springer)A review. Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant ext. that control the morphol. and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to vol. ratio, and also improves the stability towards dissoln. and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphol. anal. using SEM, field emission-SEM, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstr. showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.
- 13Liu, J.; Wang, Y.; Ma, J.; Peng, Y.; Wang, A. A Review on Bidirectional Analogies between the Photocatalysis and Antibacterial Properties of ZnO. J. Alloys Compd. 2019, 783, 898– 918, DOI: 10.1016/j.jallcom.2018.12.330Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvV2itw%253D%253D&md5=d49813a5160e96173333f126990e9e6aA review on bidirectional analogies between the photocatalysis and antibacterial properties of ZnOLiu, Junli; Wang, Yuhan; Ma, Jianzhong; Peng, Yi; Wang, AiqinJournal of Alloys and Compounds (2019), 783 (), 898-918CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)As a multi-functional biosafety material with outstanding anti-UV property, good photocatalytic property as well as antibacterial activity, ZnO shows promising practical applications in both researches and developments. It has been widely used in the fields such as photocatalysis, antibacterial, UV protecting and so on. The unique photoelec. properties of ZnO promise it an effective photocatalyst. And it plays an important role in many fields such as org. matter, pollution treatment, environmental cleaning materials and biol. medicine. In this review, we discussed the key factors which may affect the photocatalytic and antibacterial properties of ZnO based on the working mechanisms. Also, the methods that can be used to improve the performance of ZnO have been summarized. This review not only investigated the recent progress in the ZnO research and application development as photocatalysis and antibacterial, but also provided some useful information for researchers who are interested in engineering ZnO as photocatalysis and antibacterial agent.
- 14Nigam, A.; Saini, S.; Rai, A. K.; Pawar, S. J. Structural, Optical, Cytotoxicity, and Antimicrobial Properties of MgO, ZnO and MgO/ZnO Nanocomposite for Biomedical Applications. Ceram. Int. 2021, 47, 19515– 19525, DOI: 10.1016/j.ceramint.2021.03.289Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXotFeju7c%253D&md5=3fd15ec78baaeebaab238744467e19d1Structural, optical, cytotoxicity, and antimicrobial properties of MgO, ZnO and MgO/ZnO nanocomposite for biomedical applicationsNigam, Abhishek; Saini, Sheetal; Rai, Ambak Kumar; Pawar, S. J.Ceramics International (2021), 47 (14), 19515-19525CODEN: CINNDH; ISSN:0272-8842. (Elsevier Ltd.)In this study, MgO nanoparticles were successfully fabricated and incubated inside ZnO NPs to form MgO/ZnO nanocomposite for biomedical applications. The x-ray diffraction anal. of MgO, ZnO, and MgO/ZnO has shown the single-phase x-ray diffraction patterns through X' pert High score. The crystallite sizes were calcd. as 18 nm, 42 nm, and 53 nm, resp. The av. particle size of MgO, ZnO, and MgO/ZnO nanopowders depicted from secondary electron images of field emission electron microscopy were 56 nm, 400 nm, and 450 nm, resp. The presence of MgO NPs inside ZnO NPs was confirmed by transmission electron microscopy. The elemental dispersive spectroscopy of MgO, given the peaks of oxygen and magnesium, also showed only zinc and oxygen peaks in ZnO, which confirms no other impurities in MgO and ZnO powders. The elemental anal. of MgO/ZnO nanocomposite showed the peaks of Zinc and Oxygen, along with a tiny peak of Mg. The photoluminescence and UV-vis spectroscopy revealed the absorbance fluorescence limit of the nanomaterials. Fourier transform IR spectroscopy confirmed the several groups present in the nanocomposite. The biocompatibility of MgO, ZnO, and MgO/ZnO was obsd. with human peripheral blood mononuclear cells. The cytotoxicity studies were also performed against human cancer (liver and breast) cell lines. The MgO, ZnO, and MgO/ZnO exhibited the antimicrobial properties against Escherichia coli and Staphylococcus aureus.
- 15Qi, K.; Cheng, B.; Yu, J.; Ho, W. Review on the Improvement of the Photocatalytic and Antibacterial Activities of ZnO. J. Alloys Compd. 2017, 727, 792– 820, DOI: 10.1016/j.jallcom.2017.08.142Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtl2rt77P&md5=4b6958ca512118f0687c94627b2091a7Review on the improvement of the photocatalytic and antibacterial activities of ZnOQi, Kezhen; Cheng, Bei; Yu, Jiaguo; Ho, WingkeiJournal of Alloys and Compounds (2017), 727 (), 792-820CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)A review. Photocatalytic degrdn. is an effective method to alleviate environmental pollution caused by org. pollutants. In this work, research progress on the application of photocatalytic degrdn. and the antibacterial properties of zinc oxide (ZnO) nanomaterials is reviewed. The visible-light photo-response of ZnO has been expanded by employing various strategies, such as enhancing the photocatalytic activity of ZnO through modification of its electronic and optical properties, doping metal/nonmetal atoms, depositing noble metals, constructing heterojunctions, and coupling carbon materials, because the wide band gap of ZnO likely restricts its applications in photocatalysis. Although ZnO nanomaterials are commonly used for antibacterial applications, our understanding on the toxicity mechanisms of ZnO is limited. Some of the main toxicity mechanisms of this compd. include reactive oxygen species generation, Zn2+ release, membrane dysfunction, and nanoparticle internalization into cells. Some of the main methods that improve antibacterial activities are coating process inorg. or org. antimicrobial agents, doping ZnO, and tuning the size, morphol. characteristics, and concn. of ZnO nanomaterials. This review aims to examine the current research progress on ZnO-based nanomaterials developed for the photocatalysis of org. contaminant degrdn. and antibacterial applications.
- 16Gudkov, S. V.; Burmistrov, D. E.; Serov, D. A.; Rebezov, M. B.; Semenova, A. A.; Lisitsyn, A. B. A Mini Review of Antibacterial Properties of ZnO Nanoparticles. Front. Phys. 2021, 9, 641481 DOI: 10.3389/fphy.2021.641481
- 17Lin, M. H.; Wang, Y. H.; Kuo, C. H.; Ou, S. F.; Huang, P. Z.; Song, T. Y.; Chen, Y. C.; Chen, S. T.; Wu, C. H.; Hsueh, Y. H.; Fan, F. Y. Hybrid ZnO/Chitosan Antimicrobial Coatings with Enhanced Mechanical and Bioactive Properties for Titanium Implants. Carbohydr. Polym. 2021, 257, 117639 DOI: 10.1016/j.carbpol.2021.117639Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhvVSlsL4%253D&md5=e233f31dbae716e6e495fd08576f1397Hybrid ZnO/chitosan antimicrobial coatings with enhanced mechanical and bioactive properties for titanium implantsLin, Ming-Hong; Wang, Yan-Hsiung; Kuo, Cheng-Hsien; Ou, Shih-Fu; Huang, Pin-Zhen; Song, Tzu-Yu; Chen, Yi-Cheng; Chen, Shyi-Tien; Wu, Chien-Hui; Hsueh, Yi-Huang; Fan, Fang-YuCarbohydrate Polymers (2021), 257 (), 117639CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)A biocomposite coating comprising chitosan and ZnO deposited on a porous Ti oxide is developed to avoid orthopedic and dental implant-related infections. The coating comprised of an inner layer of nanoporous TiO2 and the outer layer of the chitosan matrix with ZnO nanoparticles. Microbiol. tests show that chitosan coating is effective against Escherichia coli (E. coli), however, its ability to inhibit bacterial adhesion is very limited. A 1.2-fold increase in the antibacterial activity of chitosan/ZnO coating against E. coli was detected as compared to the chitosan coating alone, and the chitosan/ZnO efficiently inhibited biofilm formation. In addn., the chitosan/ZnO coating exhibited improved bioactivity compared to the chitosan coating. The improvement in antibacterial properties and bioactivity of the chitosan/ZnO coating is attributed to the release of Zn2+ ions. The crit. force of scratching the chitosan/ZnO coating was approx. twice that of the chitosan coating. The potentiodynamic polarization results confirmed that the corrosion resistance of the implant with ZnO/chitosan/Ti structure was improved. In addn., cytocompatibility evaluation indicated that the chitosan/ZnO coating has good cytocompatibility in MG-63 cells as compared to pure Ti.
- 18Deng, W.; Yang, T.; Jin, L.; Yan, C.; Huang, H.; Chu, X.; Wang, Z.; Xiong, D.; Tian, G.; Gao, Y.; Zhang, H.; Yang, W. Cowpea-Structured PVDF/ZnO Nanofibers based Flexible Self-powered Piezoelectric Bending Motion Sensor towards Remote Control of Gestures. Nano Energy 2019, 55, 516– 525, DOI: 10.1016/j.nanoen.2018.10.049Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Cgsr%252FJ&md5=503391c2845eb44324545265160e5c8fCowpea-structured PVDF/ZnO nanofibers based flexible self-powered piezoelectric bending motion sensor towards remote control of gesturesDeng, Weili; Yang, Tao; Jin, Long; Yan, Cheng; Huang, Haichao; Chu, Xiang; Wang, Zixing; Xiong, Da; Tian, Guo; Gao, Yuyu; Zhang, Haitao; Yang, WeiqingNano Energy (2019), 55 (), 516-525CODEN: NEANCA; ISSN:2211-2855. (Elsevier Ltd.)Interactive human-machine interface (iHMI) is a bridge connecting human beings and robots, which has an important requirement for perceiving the change of pressure and bending angle. Here, we designed a flexible self-powered piezoelec. sensor (PES) based on the cowpea-structured PVDF/ZnO nanofibers (CPZNs) for remote control of gestures in human-machine interactive system. Due to the synergistic piezoelec. effect of hybrid PVDF/ZnO and the flexibility of polymer, this PES exhibited excellent bending sensitivity of 4.4 mV deg-1 ranging widely from 44° to 122°, fast response time of 76 ms, and good mech. stability. Besides, the PES could operate under both bending and pressing mode, show ultrahigh pressing sensitivity of 0.33 V kPa-1, with response time of 16 ms. When integrated in iHMI, the PES could be conformably covered on different curve surfaces, demonstrated accurate bending angle recording and fast recognition for realizing intelligent human-machine interaction. On this basis, the application of remote control of robotic hand was successfully realized in form of acting the same gesture as human hand synchronously. This CPZNs-based self-powered PES is distinct and unique in its structure and fundamental mechanism, and exhibits a prospective potential application in iHMI.
- 19Li, G. Y.; Li, J.; Li, Z. J.; Zhang, Y. P.; Zhang, X.; Wang, Z. J.; Han, W. P.; Sun, B.; Long, Y. Z.; Zhang, H. D. Hierarchical PVDF-HFP/ZnO Composite Nanofiber-based Highly Sensitive Piezoelectric Sensor for Wireless Workout Monitoring. Adv. Compos. Hybrid Mater. 2022, 5, 766– 775, DOI: 10.1007/s42114-021-00331-zGoogle Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXitF2hsrbF&md5=63c35add630a83513835786f220634f6Hierarchical PVDF-HFP/ZnO composite nanofiber-based highly sensitive piezoelectric sensor for wireless workout monitoringLi, Guo-Yi; Li, Jian; Li, Zhao-Jian; Zhang, Yu-Peng; Zhang, Xiao; Wang, Zi-Jun; Han, Wen-Peng; Sun, Bin; Long, Yun-Ze; Zhang, Hong-DiAdvanced Composites and Hybrid Materials (2022), 5 (2), 766-775CODEN: ACHMCL; ISSN:2522-0136. (Springer International Publishing AG)High sensitivity of sensors is extremely significant for precisely monitoring imperceptible changes of motion in real-time, which cannot be achieved by traditional piezoelec. devices. Herein, a hierarchical polyvinylidene fluoride hexafluoropropylene (PVDF-HFP)/ZnO composite nanaofiber piezoelec. sensor with highly sensitivity has been prepd. through epitaxial growing ZnO nanosheets on the surface of electrospun PVDF-HFP nanofibers. Systematic investigations have shown that their optimum pressure sensing performance with a sensitivity of 1.9 V kPa-1 and a short response time of 20 ms are achieved for forces from 0.02 to 0.5 N with excellent durability and stability up to 5000 cycles. Moreover, this sensor can precisely detect the imperceptible changes in player's motions to avoid injury from overtraining. Addnl., a Bluetooth-low-energy that tracks player's workout and transmits the output signals wirelessly to a smartphone app is utilized. The study provides a feasible approach for high-precision detecting and safety monitoring in the fields of medical, rehabilitation medicine, and workout security.
- 20Feng, W.; Chen, Y.; Wang, W.; Yu, D. A Waterproof and Breathable Textile Pressure Sensor with High Sensitivity based on PVDF/ZnO Hierarchical Structure. Colloids Surf., A 2022, 633, 127890 DOI: 10.1016/j.colsurfa.2021.127890Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXisFWgsL%252FM&md5=c08841bd0f14bd00a58eca79a4de2022Waterproof and breathable textile pressure sensor with high sensitivity based on polyvinylidene fluoride/zinc oxide hierarchical structureFeng, Wanqi; Chen, Yixiang; Wang, Wei; Yu, DanColloids and Surfaces, A: Physicochemical and Engineering Aspects (2022), 633 (Part_2), 127890CODEN: CPEAEH; ISSN:0927-7757. (Elsevier B.V.)Smart wearable devices based on piezoelec. effect are widely used, but it is a great challenge to ensure the breathability and waterproof of piezoelec. devices. Therefore, we use conductive fabric (CF) as electrode material. ZnO nanorods (NRs) were grown on one side of one CF, and electrospun PVDF nanofiber membrane was sandwiched between the CF with ZnO NRs and the other CF. Attributed to this structure, the pressure sensor has waterproof property and maintains good breathability. Furthermore, the sensor with the ZnO NRs/PVDF hierarchical structure piezoelec. layer can generate an output voltage of 1.60 ± 0.08 V at 150 kPa, which is more than 10 times higher than that of pure PVDF nanofiber membrane, and has a sensitive linear response in the wide range of 3-150 kPa (11.07 mV kPa-1). Moreover, after the sensor had experienced 3600 cycles of pressing, the output voltage basically remained unchanged. In addn., sliding on the sensor at a certain pressure can produce regular fluctuating signals, and the FEM is used to explain the principle of this process. Benefiting from the unique properties, the sensor can be installed on clothes to monitor the environment in real time like wind or rainfall.
- 21Li, J.; Zhao, C.; Xia, K.; Liu, X.; Li, D.; Han, J. Enhanced Piezoelectric Output of the PVDF-TrFE/ZnO Flexible Piezoelectric Nanogenerator by Surface Modification. Appl. Surf. Sci. 2019, 463, 626– 634, DOI: 10.1016/j.apsusc.2018.08.266Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhs1Kgsb7O&md5=37bd7350aa13c5ac6bee1106ff175350Enhanced piezoelectric output of the PVDF-TrFE/ZnO flexible piezoelectric nanogenerator by surface modificationLi, Jie; Zhao, Chunmao; Xia, Kai; Liu, Xi; Li, Dong; Han, JingApplied Surface Science (2019), 463 (), 626-634CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)In this paper, ZnO nano-particles (NPs) were modified by adding a dispersant (n-propylamine, PA) and a silane coupling agent (1H,2H,1H,2H-perfluorooctyltriethylsilane, PFOES) simultaneously. Further, the PVDF-TrFE/modified ZnO composite films with high crystallinity and large sp. surface area were prepd., which acted as the active layer of the piezoelec. nanogenerator (PENG). Four species of films, pure PVDF-TrFE, PVDF-TrFE/ZnO, PVDF-TrFE/ZnO@PA and PVDF-TrFE/ZnO@PA@PFOES were marked P-0-0-0, P-Z-0-0, P-Z-P-0 and P-Z-P-P, resp. The cryst. phases of the films were detd. by Fourier IR spectroscopy (FT-IR) and wide-angle X-ray diffraction (WXRD). Scanning electron microscope (SEM), Laser scanning confocal microscope (LSCM), Atomic force microscope (AFM) and water contact angle (WCA) measurements were employed to analyze the surface morphol. of the films. The thermal properties of the materials were characterized with a differential scanning calorimeter (DSC). From the FTIR spectra and WXRD pattern, it was notable that the modified ZnO NPs promoted the crystn. of β-phase. The results showed that the crystallinity of P-Z-P-P was increased by 36.12% compared to P-0-0-0. Combined with the results of SEM, LSCM and AFM, it can be concluded from WCA that modified ZnO NPs can increase the sp. surface area of the film. The piezoelec. strain const. d33 value of P-Z-P-P film was 73.5% higher than that of P-0-0-0 film, and the output voltage value of ITO/P-Z-P-P/Au PENG increased 24.4% than that of ITO/P-0-0-0/Au PENG. After 1000 cycles of testing, the output voltage of the ITO/P-Z-P-P/Au PENG has been maintained at 2.40 V, indicating that the generator exhibited the high mech. endurance. By clarifying the mechanism of surface modification, it can be concluded that enhanced piezoelec. output of the PENG is contributed to both higher β-phase content and larger charge collecting area by surface modification.
- 22Fu, H.; Long, Z.; Lai, M.; Cao, J.; Zhou, R.; Gong, J.; Chen, Y. Quantum Dot Hybridization of Piezoelectric Polymer Films for Non-Transfer Integration of Flexible Biomechanical Energy Harvesters. ACS Appl. Mater. Interfaces 2022, 14, 29934– 29944, DOI: 10.1021/acsami.2c07297Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhsFCqtLnK&md5=f470fe00ced43b9176c5acc5bd378993Quantum Dot Hybridization of Piezoelectric Polymer Films for Non-Transfer Integration of Flexible Biomechanical Energy HarvestersFu, Haiyan; Long, Zuchang; Lai, Mingxuan; Cao, Junhao; Zhou, Rihui; Gong, Jianliang; Chen, YiwangACS Applied Materials & Interfaces (2022), 14 (26), 29934-29944CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)This work presents a low-temp. engineering strategy, from quantum dot (QD) synthesis to fabrication of a hybrid from a homogeneous dispersion to thermal annealing with elaborate use of a small org. mol. dopamine, for achieving a kind of ZnO QD-hybridized piezoelec. polymer film directly integrated into a flexible electrode and a plastic substrate. This strategy is the key for non-transfer assembly of flexible piezoelec. nanogenerators (FPENGs) with both mech. robustness and high elec. performance via direct lamination. The rational addn. of dopamine plays multiple roles of (1) significantly decreasing the size of ZnO particles to a QD level (3.77 nm), (2) formation of a stable and homogeneous dispersion of a ZnO QDs/piezoelec. polyvinylidene fluoride-co-hexafluoropropylene copolymer for uniform hybridization of a piezoelec. film, and (3) increment of the piezoelec. phase via induced crystn. at a low annealing temp. This dopamine-assisted low-temp. annealing strategy for a hybrid piezoelec. film with a high d33 value (~ 31.56 pC/N, 30.56% larger than that of a pure piezoelec. polymer film) required no addnl. high-voltage polarization treatment and effectively avoided the delamination, distortion, or melt phenomenon between the piezoelec. layer, flexible electrode, and plastic protective layer caused by the high temp. and thermal stress. The obtained FPENGs showed significantly enhanced output performance and mech. robustness under repeated impact and large amts. of strain conditions. Their specific output voltage and charge d. were stably maintained at 7.16 V and 2.40 nC/cm2, which were 30.7 and 50.0% higher than those of FPENGs based on a pure piezoelec. polymer film, resp. They were further used as biomech. energy harvesters for generating electricity to charge capacitor energy storage devices for power electronics and self-powered sensors for visual motion-detecting systems, indicating their promising applications in both wearable technol. and smart homes.
- 23Huang, P.; Xu, S.; Zhong, W.; Fu, H.; Luo, Y.; Xiao, Z.; Zhang, M. Carbon Quantum Dots Inducing Formation of β Phase in PVDF-HFP to Improve the Piezoelectric Performance. Sens. Actuators, A 2021, 330, 112880 DOI: 10.1016/j.sna.2021.112880Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtlSqsbvE&md5=8f965a50a008d40d0853f77ba1d96dc5Carbon quantum dots inducing formation of β phase in PVDF-HFP to improve the piezoelectric performanceHuang, Ping; Xu, Shunjian; Zhong, Wei; Fu, Haiyan; Luo, Yongping; Xiao, Zonghu; Zhang, MengSensors and Actuators, A: Physical (2021), 330 (), 112880CODEN: SAAPEB; ISSN:0924-4247. (Elsevier B.V.)Flexible piezoelec. sensors (FPS) have been widely applied to intelligent robot, human/machine interaction and human health measurement system, etc. To improve the piezoelec. performance of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), carbon quantum dots (CQDs) were introduced to form PVDF-HFP/CQDs piezoelec. film. Owing to their large sp. surface area (96.3 m2/g) and abundant surface defects, CQDs provide mass potential induced active points for the formation of β phase in PVDF-HFP, and rich surface functional groups (-COOH, -OH and -NH2, etc) which could promote chem. bond with PVDF-HFP. The content of β phase in the PVDF-HFP/CQDs film is increased by 14.4 % compared with that in the PVDF-HFP film. Thereby, PVDF-HFP/CQDs based FPS exhibit better sensitivity (36.6 mV/g) than PVDF-HFP based FPS (25.7 mV/g) with good linearity (R2 > 99 %). Besides, the FPS show excellent mech. stability under repeated dynamic loading. On this basis, some potential applications of the PVDF-HFP/CQDs based self-powered FPS were explored, including anti-touch alarm system, finger bending detection, voice recognition and vibration monitoring.
- 24Ghirardello, M.; Ramos-Soriano, J.; Galan, M. C. Carbon Dots as an Emergent Class of Antimicrobial Agents. Nanomaterials 2021, 11, 1877, DOI: 10.3390/nano11081877Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXitlWisrzF&md5=6f4c4c008b73af2d57e886da218e8aa5Carbon Dots as an Emergent Class of Antimicrobial AgentsGhirardello, Mattia; Ramos-Soriano, Javier; Galan, M. CarmenNanomaterials (2021), 11 (8), 1877CODEN: NANOKO; ISSN:2079-4991. (MDPI AG)Antimicrobial resistance is a recognized global challenge. Tools for bacterial detection can combat antimicrobial resistance by facilitating evidence-based antibiotic prescribing, thus avoiding their overprescription, which contributes to the spread of resistance. Unfortunately, traditional culture-based identification methods take at least a day, while emerging alternatives are limited by high cost and a requirement for skilled operators. Moreover, photodynamic inactivation of bacteria promoted by photosensitizers could be considered as one of the most promising strategies in the fight against multidrug resistance pathogens. In this context, carbon dots (CDs) have been identified as a promising class of photosensitizer nanomaterials for the specific detection and inactivation of different bacterial species. CDs possess exceptional and tuneable chem. and photoelec. properties that make them excellent candidates for antibacterial theranostic applications, such as great chem. stability, high water soly., low toxicity and excellent biocompatibility. In this review, we will summarize the most recent advances on the use of CDs as antimicrobial agents, including the most commonly used methodologies for CD and CD/composites syntheses and their antibacterial properties in both in vitro and in vivo models developed in the last 3 years.
- 25Dong, X.; Liang, W.; Meziani, M. J.; Sun, Y. P.; Yang, L. Carbon Dots as Potent Antimicrobial Agents. Theranostics 2020, 10, 671, DOI: 10.7150/thno.39863Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhs1OnsLvN&md5=332457de98cb4063c998b65deb0022caCarbon dots as potent antimicrobial agentsDong, Xiuli; Liang, Weixiong; Meziani, Mohammed J.; Sun, Ya-Ping; Yang, LijuTheranostics (2020), 10 (2), 671-686CODEN: THERDS; ISSN:1838-7640. (Ivyspring International Publisher)A review. Carbon dots (CDots) have emerged to represent a highly promising new platform for visible/natural light-activated microbicidal agents. In this article, the syntheses, structures, and properties of CDots are highlighted, representative studies on their activities against bacteria, fungi, and viruses reviewed, and the related mechanistic insights discussed. Also highlighted and discussed are the excellent opportunities for potentially extremely broad applications of this new platform, including theranostics uses.
- 26Khan, F.; Akhtar, N.; Jalal, N.; Hussain, I.; Szmigielski, R.; Hayat, M. Q.; Ahmad, H. B.; El-Said, W. A.; Yang, M.; Janjua, H. A. Carbon-Dot Wrapped ZnO Nanoparticle-based Photoelectrochemical Sensor for Selective Monitoring of H2O2 Released from Cancer Cells. Microchim. Acta 2019, 186, 127, DOI: 10.1007/s00604-019-3227-x
- 27Xu, Q.; Cai, H.; Li, W.; Wu, M.; Wu, Y.; Gong, X. Carbon Dot/Inorganic Nanomaterial Composites. J. Mater. Chem. A 2022, 10, 14709– 14731, DOI: 10.1039/D2TA02628GGoogle Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xhs1yitrnO&md5=950fee6b2edd4448046b8d7bb7fed80aCarbon dot/inorganic nanomaterial compositesXu, Qingqing; Cai, Huawei; Li, Wenjing; Wu, Min; Wu, Yongzhong; Gong, XiaoJournal of Materials Chemistry A: Materials for Energy and Sustainability (2022), 10 (28), 14709-14731CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)A review. Carbon dots (CDs), a carbon-based 0-dimensional fluorescent material with a simple prepn. method, wide range of raw materials, and excellent phys. and chem. properties, have attracted the attention of many researchers in recent years because of their stable and adjustable photoluminescence properties, good biocompatibility, and abundant surface defects. Composites of CDs and inorg. nanomaterials with excellent phys. properties can expand the application scope of CDs, make up for the limitation of single-component CDs in applications, and improve the application performance of inorg. nanomaterials and enhance the versatility of inorg. nanomaterials. Such composite materials have been widely used in sensing, catalysis, biol., and optoelectronics. This review summarizes the prepn. methods and formation mechanism of carbon dot/inorg. nanohybrid materials, introduces the properties and junctions of CDs/inorg. nanohybrid materials, and outlines the applications of nanohybrid materials in the fields of sensing, therapeutic systems, catalysis, photoelec. devices and so on. Finally, the development prospects and challenges in prepg. and applying CDs/inorg. nanomaterials are discussed.
- 28Tian, Z.; Zhang, X.; Li, D.; Zhou, D.; Jing, P.; Shen, D.; Qu, S.; Zboril, R.; Rogach, A. L. Full-Color Inorganic Carbon Dot Phosphors for White-Light-Emitting Diodes. Adv. Opt. Mater. 2017, 5, 1700416 DOI: 10.1002/adom.201700416Google ScholarThere is no corresponding record for this reference.
- 29Li, S.; Li, L.; Tu, H.; Zhang, H.; Silvester, D. S.; Banks, C. E.; Zou, G.; Hou, H.; Ji, X. The Development of Carbon Dots: From the Perspective of Materials Chemistry. Mater. Today 2021, 51, 188, DOI: 10.1016/j.mattod.2021.07.028Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhslCnt7rM&md5=2a9382213d11111226dc51422b1e873eThe development of carbon dots: From the perspective of materials chemistryLi, Shuo; Li, Lin; Tu, Hanyu; Zhang, Hao; Silvester, Debbie S.; Banks, Craig E.; Zou, Guoqiang; Hou, Hongshuai; Ji, XiaoboMaterials Today (Oxford, United Kingdom) (2021), 51 (), 188-207CODEN: MTOUAN; ISSN:1369-7021. (Elsevier Ltd.)A review. The advance of materials chem. has influenced significantly the lifestyle of mankind. By virtue of their fascinating physicochem. nature - including ultrasmall size (<10 nm), rich functional groups, fluorescence, chem. stability, biocompatibility, and nontoxicity - carbon dots have been acclaimed as another epoch-making carbon-based nanomaterial following on from fullerene, nanotubes, and graphene. However, the field of carbon dot-based materials chem. remains incomplete because of their wide structural diversity, meaning that much fundamental knowledge still needs to be uncovered. Herein, this review proposed several novel viewpoints in term of carbon dot-based material chem., including the development history, classification, design principle and applications of carbon dots-based materials. Finally, several sound prospects in this fascinating filed are also given.
- 30Fu, H.; Tan, L.; Shi, Y.; Chen, Y. Tunable Size and Sensitization of ZnO Nanoarrays as Electron Transport Layers for Enhancing Photocurrent of Photovoltaic Devices. J. Mater. Chem. C 2015, 3, 828– 835, DOI: 10.1039/C4TC01981DGoogle Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVSis7jO&md5=e674a56345d83ecbbaea8ed72cf66deaTunable size and sensitization of ZnO nanoarrays as electron transport layers for enhancing photocurrent of photovoltaic devicesFu, Haiyan; Tan, Licheng; Shi, Yueqin; Chen, YiwangJournal of Materials Chemistry C: Materials for Optical and Electronic Devices (2015), 3 (4), 828-835CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)Tunable size ZnO nanoarrays (NAs) sensitized with CdS, Ag2S, CdS/Ag2S quantum dots and soln. processed 2-(2-(2-methoxyethoxy) ethoxy) Et undec-10-enyl malonate (EEMC) fullerenes were developed as electron transport layers for improving polymer solar cells performance. ZnO NAs could provide direct and ordered electron channels for electron transportation. The optimized thickness of ZnO NAs was detd. by contrast expts. with P3HT:PC61BM active layers. CdS, Ag2S shell and CdS/Ag2S double-shells could passivate the surface defects of ZnO NAs, increase the electron mobility and enhance light absorption. Moreover, EEMC assists the infiltration of the active layer into inorg. nanoarrays. Consequently, the performance of the inverted device based on thieno[3,4-b]-thiophene/benzodithiophene (PTB7):[6,6]-Ph C71-butyric acid Me ester (PC71BM) with ZnO/CdS/Ag2S/EEMC core/multi-shells NAs as electron transport layer was greatly improved to 7.7% with a high short-circuit c.d. of 17.9 mA cm-2. Moreover, the fabrication process was low-cost and environment-friendly, which would be in favor of a large-scale prodn. of polymer solar cells.
- 31Verma, R.; Pathak, S.; Srivastava, A. K.; Prawer, S.; Tomljenovic-Hanic, S. ZnO nanomaterials: Green Synthesis, Toxicity Evaluation and New Insights in Biomedical Applications. J. Alloys Compd. 2021, 876, 160175 DOI: 10.1016/j.jallcom.2021.160175Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtV2gsLfP&md5=88342880a6a501c093d29a4278816a58ZnO nanomaterials: Green synthesis, toxicity evaluation and new insights in biomedical applicationsVerma, Rajni; Pathak, Saurabh; Srivastava, Avanish Kumar; Prawer, Steven; Tomljenovic-Hanic, SnjezanaJournal of Alloys and Compounds (2021), 876 (), 160175CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)A review. Nanotechnol. has engraved new insight into the material sciences and zinc oxide nanomaterials (ZnO NMs) are one of the most extensively used materials in healthcare and environmental remediation applications attributable to their biodegradability and tunable phys. and chem. properties. This review concs. on three aspects of ZnO NMs. Firstly, we review green methods of the synthesis of ZnO NMs as an alternative to conventional synthesis routes as the latter pose environmental risks such as the requirement of hazardous and expensive precursors as well as prodn. of unwanted end products. Also, green methods can produce important and diversified morphologies. Secondly, ZnO NMs are ubiquitous in numerous biol. fields and other consumer products which motivate us to review advances in assessing their toxicol. effects via in-vitro and in-vivo studies. Thirdly, an emerging application space for ZnO NMs is bioimaging, biosensing and traceable drug delivery which take advantage of their unique variable optical properties and in particular, their fluorescent behavior. The inhibitory action of these NMs against microbes, cancer and inflammation is also covered. The aim is to provide crit. review on perspectives and challenges assocd. with fluorescent-based nascent applications that can be utilized for targeting, detecting and treating severe human ailments.
- 32Kang, Z.; Lee, S. T. Carbon Dots: Advances in Nanocarbon Applications. Nanoscale 2019, 11, 19214– 19224, DOI: 10.1039/C9NR05647EGoogle Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1SgtbvL&md5=f0213e78110725dfb81086f943e02a01Carbon dots: advances in nanocarbon applicationsKang, Zhenhui; Lee, Shuit-TongNanoscale (2019), 11 (41), 19214-19224CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Carbon dots (C-Dots), defined by characteristic sizes of <10 nm, have become a rising star in carbon nanomaterials. C-Dots possess many unique physiochem. and photochem. properties which make them a promising platform for imaging, environmental, catalytic, biol. and energy-related applications. To date, C-Dots have been investigated extensively, and their related applications have developed rapidly. However, quant. understanding of the physiochem. properties of C-Dots still remains a difficult challenge because of their complex structures. Here, we will highlight the recent progress in the practical applications of C-Dots, with particular attention to the research in light-emitting devices, bioimaging and biodetection, catalysis, functional materials, and agriculture.
- 33Wareing, T. C.; Gentile, P.; Phan, A. N. Biomass-based Carbon Dots: Current Development and Future Perspectives. ACS Nano 2021, 15, 15471– 15501, DOI: 10.1021/acsnano.1c03886Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXitFWjsrrN&md5=21d3f80890bc1033db85819b4c0c8777Biomass-based carbon dots: current development and future perspectivesWareing, Thomas C.; Gentile, Piergiorgio; Phan, Anh N.ACS Nano (2021), 15 (10), 15471-15501CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Carbon dots have been considered as a soln. to the challenges that semiconductor quantum dots have encountered because they are more biocompatible and can be synthesized from abundant and nontoxic materials such as biomass. This review will highlight the advantages of these biomass-based carbon dots in terms of synthesis, properties, and applications in the biomedical field. Furthermore, future applications esp. in the biomedical field of biomass-based carbon dots as well as the challenges of semiconductor quantum dots such as biocompatibility, photobleaching, environmental challenges, toxicity, and poor soly. will be discussed in detail. Biomass-derived quantum dots, a subsection of carbon dots that are the most desirable for future research, will be focused upon including from synthesis to applications. Finally, the future development of biomass derived quantum dots in the biomedical field will be discussed and evaluated to unlock the potential for their applications.
- 34Theerthagiri, J.; Salla, S.; Senthil, R. A.; Nithyadharseni, P.; Madankumar, A.; Arunachalam, P.; Maiyalagan, T.; Kim, H. S. A Review on ZnO Nanostructured Materials: Energy, Environmental and Biological Applications. Nanotechnology 2019, 30, 392001, DOI: 10.1088/1361-6528/ab268aGoogle Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1Whu7vE&md5=abbb69d4535a58f50ded1b6899e02d59A review on ZnO nanostructured materials: energy, environmental and biological applicationsTheerthagiri, J.; Salla, Sunitha; Senthil, R. A.; Nithyadharseni, P.; Madankumar, A.; Arunachalam, Prabhakarn; Maiyalagan, T.; Kim, Hyun-SeokNanotechnology (2019), 30 (39), 392001CODEN: NNOTER; ISSN:1361-6528. (IOP Publishing Ltd.)A review. Zinc oxide (ZnO) is an adaptable material that has distinctive properties, such as high-sensitivity, large specific area, non-toxicity, good compatibility and a high isoelec. point, which favors it to be considered with a few exceptions. It is the most desirable group of nanostructure as far as both structure and properties. The unique and tuneable properties of nanostructured ZnO shows excellent stability in chem. as well as thermally stable n-type semiconducting material with wide applications such as in luminescent material, supercapacitors, battery, solar cells, photocatalysis, biosensors, biomedical and biol. applications in the form of bulk crystal, thin film and pellets. The nanosized materials exhibit higher dissoln. rates as well as higher soly. when compared to the bulk materials. This review significantly focused on the current improvement in ZnO-based nanomaterials/composites/doped materials for the application in the field of energy storage and conversion devices and biol. applications. Special deliberation has been paid on supercapacitors, Li-ion batteries, dye-sensitized solar cells, photocatalysis, biosensors, biomedical and biol. applications. Finally, the benefits of ZnO-based materials for the utilizations in the field of energy and biol. sciences are moreover consistently analyzed.
- 35Sharma, D. K.; Shukla, S.; Sharma, K.; Kumar, V. A Review on ZnO: Fundamental Properties and Applications. Mater. Today 2022, 49, 3028– 3035, DOI: 10.1016/j.matpr.2020.10.238Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtVKru7vJ&md5=0dfc5eb017518fcd042ebcbb4677a368A review on ZnO: Fundamental properties and applicationsSharma, Dhirendra Kumar; Shukla, Sweta; Sharma, Kapil Kumar; Kumar, VipinMaterials Today: Proceedings (2022), 49 (Part_8), 3028-3035CODEN: MTPAC4; ISSN:2214-7853. (Elsevier Ltd.)A review. Among the semiconductor metal oxides, some semiconductor structures are identified for their unique and vast potential applications in optoelectronic, field effect transistors, solar cells, photoluminescence devices, and dild. magnetic semiconductors, etc. The interesting development in optoelectronic applications arises due to environmentally friendly short energy, laser diodes and white light producing technologies that work beyond room temp. Out of this ZnO is an adaptable material for scientific study. The variation of ZnO properties by insertion of impurity/dopant has turn into a recent emerging matter. The phenomena of doping in ZnO. ZnO as a host material will create by researchers; tailoring its optical, structural, elec. and magnetic properties through modifying its electronic structure. Due to doping results, there is enhancement in diverse applications like electronic, spintronic, optoelectronic, photocatalytic, antibacterial, etc. These improvements in different application areas are due to its direct band gap energy, luminescence, high electron mobility, and debatable room-temp. ferromagnetic conduct in diverse structures like single crystals, thin films, powders and nanostructure. This extensively focused on the comprehensive cross-section of ZnO's luminescent, structural, optical, magnetic properties and various applications, with the key directions of development, serving as beginning, an orientation, and stimulation for upcoming research.
- 36Abolhasani, M. M.; Naebe, M.; Shirvanimoghaddam, K.; Fashandi, H.; Khayyam, H.; Joordens, M.; Pipertzis, A.; Anwar, S.; Berger, R.; Floudas, G.; Michels, J.; Asadi, K. Thermodynamic Approach to Tailor Porosity in Piezoelectric Polymer Fibers for Application in Nanogenerators. Nano Energy 2019, 62, 594– 600, DOI: 10.1016/j.nanoen.2019.05.044Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFWjsr%252FP&md5=a57e8c363fb5f0c209eeb2a5e3f25995Thermodynamic approach to tailor porosity in piezoelectric polymer fibers for application in nanogeneratorsAbolhasani, Mohammad Mahdi; Naebe, Minoo; Shirvanimoghaddam, Kamyar; Fashandi, Hossein; Khayyam, Hamid; Joordens, Matthew; Pipertzis, Achilleas; Anwar, Saleem; Berger, Ruediger; Floudas, George; Michels, Jasper; Asadi, KamalNano Energy (2019), 62 (), 594-600CODEN: NEANCA; ISSN:2211-2855. (Elsevier Ltd.)Low power d. of polymer piezoelec. nanogenerators is a major hurdle for their application as a potential mode of powering wearable and portable electronic devices. To increase the efficiency, here we suggest use of porous piezoelec. poly (vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) nanofibers. However, designing a process that allows introduction of pores in the nanometric fibers with a diam. of only several 100 nm, is highly challenging due to the intricate physics of polymer/solvent/anti-solvent interactions. Realization of the porous nanofibers would be a breakthrough in the field of piezoelec. nanogenerators. We presents an elegant approach based on the thermodn. of polymer solns. to tailor porosity in P(VDF-TrFE) nanofibers. By adding a conscious amt. of water, carefully chosen as non-solvent based on the ternary phase diagram of P(VDF-TrFE)/water/solvent, we intentionally induce liq.-phase demixing, which leads to formation of nanopores in the electrospun nanofiber. By calcg. the mean compn. trajectories, we predict and explain formation of the pores in the nanofibers, and show how little variations in initial water content substantially influences fiber porosity. Nanogenerators based on the porous electrospun P(VDF-TrFE) nanofibers show output power that systematically increases with porosity (with 500 times increase in output power for 45% porous fibers). The enhanced output is due to the reduced effective dielec. permittivity of the nanofibers. We unambiguously show that the voltage generation in nanofibers is of the same origin as in neat piezoelec. P(VDF-TrFE) films and is due to the relaxation of segments within the restricted amorphous phase. Understanding how to form nanopores, would have a major contribution to other fields, ranging from nanoporous membranes, as well as porous polymer structures for triboelec. nanogenerators.
- 37Zaarour, B.; Zhu, L.; Huang, C.; Jin, X. Controlling the Secondary Surface Morphology of Electrospun PVDF Nanofibers by Regulating the Solvent and Relative Humidity. Nanoscale Res. Lett. 2018, 13, 285, DOI: 10.1186/s11671-018-2705-0Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3c3ot1GqsA%253D%253D&md5=fe2d2e6e33dfd53d053155302de3eddaControlling the Secondary Surface Morphology of Electrospun PVDF Nanofibers by Regulating the Solvent and Relative HumidityZaarour Bilal; Zhu Lei; Huang Chen; Jin XiangyuNanoscale research letters (2018), 13 (1), 285 ISSN:1931-7573.This work presents a simple and reliable method for directly generating polyvinylidene fluoride (PVDF) nanofibers with secondary surface morphology (e.g., porous surfaces, rough surfaces, grooved surfaces, and interior porosity) by using single/binary solvent systems and relative humidity. We clarified the mechanisms responsible for the formation of these morphologies by systematically exploring the molecular interactions among the polymer, solvent(s), and water vapor. Our results proved that the formation of secondary surface morphology needed the presence of water vapor, a non-solvent of the polymer, at an appropriate level of relative humidity. The formation of secondary surface morphology was dependent on the speed of evaporation of the solvent(s) (ACE, DMF, and their mixtures), as well as the inter-diffusion and penetration of the non-solvent (water) and solvent(s). The results of N2 physical adsorption-desorption isotherms showed that the macro-porous fibers (> 300 nm) exhibited the highest specific surface area of 23.31 ± 4.30 m(2)/g and pore volume of 0.0695 ± 0.007 cm(3)/g, enabling the high oil absorption capacities of 50.58 ± 5.47 g/g, 37.74 ± 4.33 g/g, and 23.96 ± 2.68 g/g for silicone oil, motor oil, and olive oil, respectively. We believe this work may serve as guidelines for the formation of different structures of macro-porous, rough, and grooved nanofibers with interior porosity through electrospinning.
- 38da Silva, B. L.; Caetano, B. L.; Chiari-Andréo, B. G.; Pietro, R. C. L. R.; Chiavacci, L. A. Increased Antibacterial Activity of ZnO Nanoparticles: Influence of Size and Surface Modification. Colloids Surf., B 2019, 177, 440– 447, DOI: 10.1016/j.colsurfb.2019.02.013Google ScholarThere is no corresponding record for this reference.
- 39Zhang, L.; Jiang, Y.; Ding, Y.; Povey, M.; York, D. Investigation into the Antibacterial Behaviour of Suspensions of ZnO Nanoparticles (ZnO Nanofluids). J. Nanopart. Res. 2007, 9, 479– 489, DOI: 10.1007/s11051-006-9150-1Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXltFemt7c%253D&md5=1ae066b07f73f0e57aa8e7f89f0be708Investigation into the antibacterial behavior of suspensions of ZnO nanoparticles (ZnO nanofluids)Zhang, Lingling; Jiang, Yunhong; Ding, Yulong; Povey, Malcolm; York, DavidJournal of Nanoparticle Research (2007), 9 (3), 479-489CODEN: JNARFA; ISSN:1388-0764. (Springer)The antibacterial behavior of suspensions of zinc oxide nanoparticles (ZnO nanofluids) against E. Coli has been investigated. ZnO nanoparticles from two sources are used to formulate nanofluids. The effects of particle size, concn. and the use of dispersants on the antibacterial behavior are examd. The results show that the ZnO nanofluids have bacteriostatic activity against E. coli. The antibacterial activity increases with increasing nanoparticle concn. and increases with decreasing particle size. Particle concn. is obsd. to be more important than particle size under the conditions of this work. The results also show that the use of two types of dispersants (Polyethylene Glycol (PEG) and Polyvinylpyrrolidone (PVP)) does not affect much the antibacterial activity of ZnO nanofluids but enhances the stability of the suspensions. SEM analyses of the bacteria before and after treatment with ZnO nanofluids show that the presence of ZnO nanoparticles damages the membrane wall of the bacteria. Electrochem. measurements using a model DOPC monolayer suggest some direct interaction between ZnO nanoparticles and the bacteria membrane at high ZnO concns.
- 40Sirelkhatim, A.; Mahmud, S.; Seeni, A.; Kaus, N. H. M.; Ann, L. C.; Bakhori, S. K. M.; Hasan, H.; Mohamad, D. Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism. Nano-micro Lett. 2015, 7, 219– 242, DOI: 10.1007/s40820-015-0040-xGoogle Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1WiurbP&md5=ba47dda84f2dc18906ea7735acb39b61Review on zinc oxide nanoparticles: antibacterial activity and toxicity mechanismSirelkhatim, Amna; Mahmud, Shahrom; Seeni, Azman; Kaus, Noor Haida Mohamad; Ann, Ling Chuo; Bakhori, Siti Khadijah Mohd.; Hasan, Habsah; Mohamad, DasmawatiNano-Micro Letters (2015), 7 (3), 219-242CODEN: NLAEBV; ISSN:2150-5551. (Nano-Micro Letters)Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnol. to synthesize particles in the nanometer region. Many microorganisms exist in the range from hundreds of nanometers to tens of micrometers. ZnO-NPs exhibit attractive antibacterial properties due to increased sp. surface area as the reduced particle size leading to enhanced particle surface reactivity. ZnO is a bio-safe material that possesses photo-oxidizing and photocatalysis impacts on chem. and biol. species. This review covered ZnO-NPs antibacterial activity including testing methods, impact of UV illumination, ZnO particle properties (size, concn., morphol., and defects), particle surface modification, and min. inhibitory concn. Particular emphasize was given to bactericidal and bacteriostatic mechanisms with focus on generation of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), OH- (hydroxyl radicals), and O2-2 (peroxide). ROS has been a major factor for several mechanisms including cell wall damage due to ZnO-localized interaction, enhanced membrane permeability, internalization of NPs due to loss of proton motive force and uptake of toxic dissolved zinc ions. These have led to mitochondria weakness, intracellular outflow, and release in gene expression of oxidative stress which caused eventual cell growth inhibition and cell death. In some cases, enhanced antibacterial activity can be attributed to surface defects on ZnO abrasive surface texture. One functional application of the ZnO antibacterial bioactivity was discussed in food packaging industry where ZnO-NPs are used as an antibacterial agent toward foodborne diseases. Proper incorporation of ZnO-NPs into packaging materials can cause interaction with foodborne pathogens, thereby releasing NPs onto food surface where they come in contact with bad bacteria and cause the bacterial death and/or inhibition.
- 41Bowen, C. R.; Kim, H. A.; Weaver, P. M.; Dunn, S. Piezoelectric and Ferroelectric Materials and Structures for Energy Harvesting Applications. Energy Environ. Sci. 2014, 7, 25– 44, DOI: 10.1039/C3EE42454EGoogle Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFKhtrzM&md5=a0088f696e18812642e7ad4fc7d2a18cPiezoelectric and ferroelectric materials and structures for energy harvesting applicationsBowen, C. R.; Kim, H. A.; Weaver, P. M.; Dunn, S.Energy & Environmental Science (2014), 7 (1), 25-44CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)This review provides a detailed overview of the energy harvesting technologies assocd. with piezoelec. materials along with the closely related sub-classes of pyroelecs. and ferroelecs. These properties are, in many cases, present in the same material, providing the intriguing prospect of a material that can harvest energy from multiple sources including vibration, thermal fluctuations and light. Piezoelec. materials are initially discussed in the context of harvesting mech. energy from vibrations using inertial energy harvesting, which relies on the resistance of a mass to acceleration, and kinematic energy harvesting which directly couples the energy harvester to the relative movement of different parts of a source. Issues related to mode of operation, loss mechanisms and using non-linearity to enhance the operating frequency range are described along with the potential materials that could be employed for harvesting vibrations at elevated temps. In addn. to inorg. piezoelec. materials, compliant piezoelec. materials are also discussed. Piezoelec. energy harvesting devices are complex multi-physics systems requiring advanced methodologies to maximize their performance. The research effort to develop optimization methods for complex piezoelec. energy harvesters is then reviewed. The use of ferroelec. or multi-ferroic materials to convert light into chem. or elec. energy is then described in applications where the internal elec. field can prevent electron-hole recombination or enhance chem. reactions at the ferroelec. surface. Finally, pyroelec. harvesting generates power from temp. fluctuations and this review covers the modes of pyroelec. harvesting such as simple resistive loading and Olsen cycles. Nano-scale pyroelec. systems and novel micro-electro-mech.-systems designed to increase the operating frequency are discussed.
- 42Li, Z.; Zhang, X.; Li, G. In Situ ZnO Nanowire Growth to Promote the PVDF Piezo Phase and the ZnO-PVDF Hybrid Self-rectified Nanogenerator as a Touch Sensor. Phys. Chem. Chem. Phys. 2014, 16, 5475– 5479, DOI: 10.1039/c3cp54083aGoogle Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtVGitrY%253D&md5=46eaf17f68e2a094748afeb555fefbd1In situ ZnO nanowire growth to promote the PVDF piezo phase and the ZnO-PVDF hybrid self-rectified nanogenerator as a touch sensorLi, Zetang; Zhang, Xu; Li, GuanghePhysical Chemistry Chemical Physics (2014), 16 (12), 5475-5479CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)A PVDF-ZnO nanowires (NWs) hybrid generator (PZHG) was designed. A simple, cost effective method to produce the PVDF β phase by nano force is introduced. With the ZnO NWs growing, the in situ nano extension force promotes the phase change. A theor. anal. of the ZnO NWs acting as a self-rectifier of the nano generator is established. The ZnO NWs acted as a self-adjustment diode to control the current output of the PZHG by piezo-elec. and semi-conductive effects. Based on the self-controllability of the piezoelec. output, three kinds of finger touching are distinguished by the output performances of the PZHG, which is applicable to an LCD touch pad.
- 43Fu, Y.; Cheng, Y.; Chen, C.; Li, D.; Zhang, W. Study on Preparation Process and Enhanced Piezoelectric Performance of Pine-needle-like ZnO@ PVDF Composite Nanofibers. Polym. Test. 2022, 108, 107513 DOI: 10.1016/j.polymertesting.2022.107513Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XjsFGitro%253D&md5=6882d321857c97bae164c13792abe889Study on preparation process and enhanced piezoelectric performance of pine-needle-like ZnO@PVDF composite nanofibersFu, Yijun; Cheng, Yue; Chen, Chi; Li, Dawei; Zhang, WeiPolymer Testing (2022), 108 (), 107513CODEN: POTEDZ; ISSN:0142-9418. (Elsevier Ltd.)The effect of hydrothermal process on the morphol. and piezoelec. performance of zinc oxide/polyvinylidene fluoride (ZnO@PVDF) composite nanofibers is rarely studied. In this work, highly aligned ZnO nanorods were epitaxially grown on the electrospun PVDF nanofibers to form ZnO@PVDF composite nanofibers with a pine-needle-like bionic structure. Nanofibers before and after hydrothermal reaction were characterized by SEM, Fourier transform IR spectroscopy (FTIR), X-ray diffraction (XRD) and piezoelec. anal. Results demonstrated that hydrothermal reaction conditions, including mass ratio of ZnCl2 to HMTA, ammonium hydroxide vol., hydrothermal reaction time and temp. should be carefully controlled and cooperated with each other to produce ZnO nanorods with ideal microstructure and piezoelec. performance. FTIR and XRD results confirmed the transformation of β phase in PVDF nanofibers from α phase in PVDF powder due to the elongation under strong elec. field during electrospinning. Results of SEM and XRD certified the successful growth of ZnO nanorods with hexagonal wurtzite structure, which plays an important role in facilitating the percentage of β phase and the resulted piezoelec. capacity of ZnO@PVDF composite nanofibers. All of these characterizations suggest that the proposed pine-needle-like ZnO@PVDF composite nanofibers demonstrate promising potential in the wide application of electromech. energy conversion.
- 44Martins, P.; Lopes, A. C.; Lanceros-Mendez, S. Electroactive Phases of Poly (vinylidene fluoride): Determination, Processing and Applications. Prog. Polym. Sci. 2014, 39, 683– 706, DOI: 10.1016/j.progpolymsci.2013.07.006Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlahu73L&md5=a2bd61638e7b15bdd4ab0f6527c9e445Electroactive phases of poly(vinylidene fluoride): Determination, processing and applicationsMartins, P.; Lopes, A. C.; Lanceros-Mendez, S.Progress in Polymer Science (2014), 39 (4), 683-706CODEN: PRPSB8; ISSN:0079-6700. (Elsevier Ltd.)A review. Poly(vinylidene fluoride), PVDF, and its copolymers are the family of polymers with the highest dielec. const. and electroactive response, including piezoelec., pyroelec. and ferroelec. effects. The electroactive properties are increasingly important in a wide range of applications such as in biomedicine, energy generation and storage, monitoring and control, and include the development of sensors and actuators, separator and filtration membranes and smart scaffolds, among others. For many of these applications the polymer should be in one of its electroactive phases. This review presents the developments and summarizes the main characteristics of the electroactive phases of PVDF and copolymers, indicates the different processing strategies as well as the way in which the phase content is identified and quantified. Addnl., recent advances in the development of electroactive composites allowing novel effects, such as magnetoelec. responses, and opening new applications areas are presented. Finally, some of the more interesting potential applications and processing challenges are discussed.
- 45Anand, A.; Meena, D.; Bhatnagar, M. C. Synthesis and Characterization of Flexible PVDF/Bi2Al4O9/RGO based Piezoelectric Materials for Nanogenerator Application. J. Alloys Compd. 2020, 843, 156019 DOI: 10.1016/j.jallcom.2020.156019Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlajt7%252FP&md5=9fcb378604971c7da38e3accc819f702Synthesis and characterization of flexible polyvinylidenefluoride/bismuth aluminate/reduced graphene oxide based piezoelectric materials for nanogenerator applicationAnand, Abhishek; Meena, Deshraj; Bhatnagar, M. C.Journal of Alloys and Compounds (2020), 843 (), 156019CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)Flexible polymer-based piezoelec. nanogenerators have attracted the researchers the most due to their mech. flexibility, low fabrication cost and pollution-free energy harvesting from sources such as vibration, mech. load, human motion and waste heat. Here, we report a flexible piezoelec. nanogenerator with different kinds of nanofiller such as reduced graphene oxide and bismuth aluminate Bi2Al4O9 ceramic in Polyvinylidene fluoride (PVDF) matrix. The structural and morphol. properties of nanocomposite films are examd. by X-ray diffraction (XRD) and SEM (SEM). The Fourier transform IR spectroscopy (FTIR) studies revealed the fraction of β-phase enhancement from 53 to 76% with incorporation of these nanofillers. The nanocomposite films of PVDF/Bi2Al4O9/RGO showed max. value of remnant polarization (Pr) is 0.0189μC/cm2 at an elec. field of 165 kV/cm and the value of elec. output voltage and current generated from nanocomposite films is 5.92 V and 0.76μA for PVDF/Bi2Al4O9/RGO based nanocomposite. The PVDF/Bi2Al4O9/RGO based nanocomposite generates a max. output power d. of 0.457μW/cm2 at 12 MΩ resistance which is around 20 times more than that of bare PVDF film.
- 46Bodkhe, S.; Turcot, G.; Gosselin, F. P.; Therriault, D. One-Step Solvent Evaporation-Assisted 3D Printing of Piezoelectric PVDF Nanocomposite Structures. ACS Appl. Mater. Interfaces 2017, 9, 20833– 20842, DOI: 10.1021/acsami.7b04095Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXos1ans70%253D&md5=d9f1390902bab4e251d873dc9fa2a9b2One-Step Solvent Evaporation-Assisted 3D Printing of Piezoelectric PVDF Nanocomposite StructuresBodkhe, Sampada; Turcot, Gabrielle; Gosselin, Frederick P.; Therriault, DanielACS Applied Materials & Interfaces (2017), 9 (24), 20833-20842CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Development of a 3-dimensional printable material system possessing inherent piezoelec. properties to fabricate integrable sensors in a single-step printing process without poling is of importance to the creation of a wide variety of smart structures. Here, the authors study the effect of addn. of barium titanate nanoparticles in nucleating piezoelec. β-polymorph in 3-dimensional printable polyvinylidene fluoride (PVDF) and fabrication of the layer-by-layer and self-supporting piezoelec. structures on a micro- to millimeter scale by solvent evapn.-assisted 3-dimensional printing at room temp. The nanocomposite formulation obtained after a comprehensive study of compn. and processing techniques possesses a piezoelec. coeff., d31, of 18 pC N-1, which is comparable to that of typical poled and stretched com. PVDF film sensors. A 3-dimensional contact sensor that generates up to 4 V upon gentle finger taps demonstrates the efficacy of the fabrication technique. The authors' 1-step 3-dimensional printing of piezoelec. nanocomposites can form ready-to-use, complex-shaped, flexible, and lightwt. piezoelec. devices. When combined with other 3-dimensional printable materials, they could serve as stand-alone or embedded sensors in aerospace, biomedicine, and robotic applications.
Citation Statements
beta
Smart citations by scite.ai include citation statements extracted from the full text of the citing article. The number of the statements may be higher than the number of citations provided by ACS Publications if one paper cites another multiple times or lower if scite has not yet processed some of the citing articles.
- SupportingSupporting0
- MentioningMentioning4
- ContrastingContrasting0
Explore this article's citation statements on scite.ai
This article is cited by 2 publications.
- Guanxiong Liu, Baoqiang Li, Jie Li, Jiaxin Dong, Vladimir E. Baulin, Yujie Feng, Dechang Jia, Yuri V. Petrov, Aslan Yu Tsivadze, Yu Zhou. EGTA-Derived Carbon Dots with Bone-Targeting Ability: Target-Oriented Synthesis and Calcium Affinity. ACS Applied Materials & Interfaces 2023, 15
(34)
, 40163-40177. https://doi.org/10.1021/acsami.3c05184
- Yumeng Gao, Wentao Wang, Wang Xu, Baohong Sun, Jing Wu, Xiaoyu Xu, Xiaohong Chu, Ninglin Zhou, Ming Zhang, Jian Shen. Three-Pronged Flower-like Nanoplatforms for the Photothermal/Photodynamic/Quaternary Ammonium Salt Synergistic Antibacterial Method and Bioimaging. Langmuir 2023, 39
(28)
, 9734-9743. https://doi.org/10.1021/acs.langmuir.3c00769
