纳米发电机可将机械能转换为电能

美国乔治亚工学院报道,他们制成了纳米尺寸的发电机样机,这种发电机可利用环境产生的机械能（如超声波、机械振动、血液流动之类）产生出连续的直流电流。一些垂直排列的纳米线由氧化锌组成,由它们驱动内部新型曲折的板电极,从而使发电机向纳米尺寸的器件供电,而无需电池或其他外部电源。纳米发电机利用氧化锌纳米结构的独特的压电效应与半导体特性的结合,当它们弯折时会产生少量电荷。     

纳米润滑技术的进展

纳米技术的飞速发展，给润滑材料的进步提供了广阔的技术空间，纳米润滑材料充分利用了在纳米材料的结构效应(小尺寸效应、量子化效应、表面效应和界面效应)赋予润滑材料很多奇特的性能。本介绍了纳米润滑研究的一些进展，以及一种新型的纳米润滑技术——自修复纳米润滑添加剂的基本原理和初步研究成果。     

基于碳纳米管的纳米泵浦系统模拟研究

碳纳米管的纳米泵浦效应在药物传输、新型纳米推进器与传感器等方面有着广泛的潜在应用,而纳米泵浦效应能够获得应用的前提是建立稳定的纳米泵浦系统。通过分子动力学模拟,研究了基于碳纳米管的稳定纳米泵浦系统的建立方法和影响纳米泵浦效应的关键因素＂泵浦系统的边界势垒＂;在建立稳定泵浦系统和克服边界势垒的条件下,模拟了在外界驱动下的纳米泵浦过程。该项研究的结果为碳纳米管纳米泵浦效应的应用提供了重要理论参考。     

静电纺丝法制备磁性纳米纤维材料的研究进展

磁性纳米纤维材料不但具有普通纳米粒子的特殊效应,而且具有独特的形状各向异性和磁晶各向异性效应,在高密度磁记录、电磁波吸收、催化剂、医学和生物功能材料等领域具有重要应用。静电纺丝技术已被证明是一种制备纳米纤维最简单有效的方法。结合最新文献,重点阐述了以静电纺丝技术为主的磁性纳米纤维制备工艺以及不同工艺对磁性纳米纤维的形貌和性能的影响。简要介绍了磁性纳米纤维的应用,指出了发展新型结构可控磁性纳米纤维材料、研究其定向排布及组装技术、开发其在各领域的实际应用是未来主要的研究方向。     

一维纳米材料中的新效应和新功能

详细综述了一维纳米材料中的新效应和新功能研究的新进展,包括光开关效应、线栅偏振效应、场发射效应、热电效应、压电效应、储氢效应、敏感效应,分析了这些纳米材料效应产生的原理以及与纳米材料的关系,指出了一维纳米材料中新效应和新功能是设计下一代纳米器件的基础.文章中还简要的介绍了纳米器件研究的新进展.     

纳米酶:一种抗微生物感染新方法（英文）

细菌和病毒一直对人类健康构成威胁。SARS-CoV-2已经在世界各地肆虐了近三年,给人类健康带来了巨大危险。面对细菌的抗药性和抗生素治疗效果不佳等种种挑战,人们迫切需要新的方法来对抗致病微生物。最近,具有内在酶活性的纳米酶作为一种有前途的新型“抗生素”,通过催化生成大量活性氧,在生理条件下表现出卓越的抗菌和抗病毒活性。此外,基于纳米酶的治疗中,纳米材料在独特的物理化学特性(如光热和光动力效应)的帮助下可以增强治疗效果。本文综述了纳米酶在抗菌、抗病毒-方向的研究进展,从机制角度系统总结分析了纳米酶消除细菌、病毒等微生物的原理,对未来的新型纳米抗菌抗病毒材料的研发方向及其所面临的挑战进行了展望,为开发下一代抗微生物感染纳米酶提供了思路。     

黏弹性基体中变截面挠曲电Timoshenko纳米梁振动特性研究EI北大核心CSCD

以黏弹性基体中的Timoshenko纳米梁为研究对象,综合考虑非局部效应、截面非均匀性、压电效应和挠曲电效应的影响,建立了变截面挠曲电纳米梁的自由振动控制方程,基于摄动理论给出了典型边界条件下结构自由振动控制方程的传递函数求解方法,较系统研究了非局部参数、截面非均匀性、挠曲电系数以及基体黏弹性对结构振动特性的影响规律。结果表明:增大截面锥度能减小结构固有频率对非局部效应的敏感程度,并带来结构临界阻尼系数的减小;增大非局部参数能削弱结构固有频率对截面锥度的敏感程度;增大切向挠曲电系数f_(3131)可削弱结构对横向挠曲电系数f_(3131)的敏感程度,而增大横向挠曲电系数f_(3131)却增加结构对切向挠曲电系数f_(3131)的敏感程度。相关研究成果可为挠曲电纳米梁在俘能器中的推广应用提供理论基础。     

石墨烯-金纳米复合物的制备及应用研究进展

石墨烯-金纳米复合物由于融合了石墨烯以及金纳米粒子的优良性质,具有良好的光热效应、电学特性及催化效应。近年来,石墨烯-金纳米复合物在生物医药、催化剂、光学等领域都有着广阔的应用。阐述了几种石墨烯-金纳米复合物的制备方法,分析了各种合成方法的优缺点,讨论了石墨烯-金纳米复合物的应用进展以及开发前景。     

柔性压电纳米发电机研究进展

<正>压电纳米发电机是一种利用压电效应将机械能转换为电能的器件。在外界机械作用下,压电材料产生的极化电荷和随时间变化的电场可驱动电子在外电路发生流动,进而产生电能。近年来,柔性电子器件在可穿戴、可植入电子器件等方面得到了广泛应用。压电纳米发电机需要对复杂机械作用如弯曲、拉伸、扭转等产生响应并输出电能,且适应不同形状的表面以满足可穿戴、可植入等要求。因此,开发出具备很好的柔性和稳定性的压电纳米     

纳米荧光探针在药物输送中的应用

药物载体的开发具有悠久的历史,但是传统的药物载体并不具备可观察性和可追踪性,将纳米荧光探针应用于药物载体中有望解决此问题。重点概述了纳米荧光探针应用于药物载体中的实例以及新型药物载体的开发应用,探讨了不同纳米荧光探针的优缺点。     

Synthesis of Ga-doped ZnO nanorods using an aqueous solution method for a piezoelectric nanogenerator

Mechanical energy is a potential energy source for self-powered electronic devices. Due to their unique semiconducting and piezoelectric properties, wurtzite-structured nanomaterials have been considered as potential candidates for piezoelectric nanogenerators that convert mechanical energy into electricity. In the present work, we report on the growth of Ga-doped ZnO (GZO) nanorods and investigate the performance of nanogenerators fabricated from undoped ZnO (UZO) nanorods, low Ga-doped ZnO (LGZO) nanorods, and high Ga-doped ZnO (HGZO) nanorods. A nanogenerator integrated with LGZO nanorods exhibited a current density of 1.2 microA/cm2, an enhancement over the 0.4 microA/cm2 and 0.7 microA/cm2 current densities of nanogenerators integrated with UZO and HGZO nanorods, respectively.     

Hybrid Energy Harvesters: Toward Sustainable Energy Harvesting

Recently, sustainable green energy harvesting systems have been receiving great attention for their potential use in self‐powered smart wireless sensor network (WSN) systems. In particular, though the developed WSN systems are able to advance public good, very high and long‐term budgets will be required in order to use them to supply electrical energy through temporary batteries or connecting power cables. This report summarizes recent significant progress in the development of hybrid nanogenerators for a sustainable energy harvesting system that use natural and artificial energies such as solar, wind, wave, heat, machine vibration, and automobile noise. It starts with a brief introduction of energy harvesting systems, and then summarizes the different hybrid energy harvesting systems: integration of mechanical and photovoltaic energy harvesters, integration of mechanical and thermal energy harvesters, integration of thermal and photovoltaic energy harvesters, and others. In terms of the reported hybrid nanogenerators, a systematic summary of their structures, working mechanisms, and output performances is provided. Specifically, electromagnetic induction, triboelectric, piezoelectric, photovoltaic, thermoelectric, and pyroelectric effects are reviewed on the basis of the individual and hybrid power performances of hybrid nanogenerators and their practical applications with various device designs. Finally, the perspectives on and challenges in developing high performance and sustainable hybrid nanogenerator systems are presented.     

Multilayered flexible nanocomposite for hybrid nanogenerator enabled by conjunction of piezoelectricity and triboelectricity

We fabricate a flexible hybrid nanogenerator (HNG),based on multilayered nanocomposite materials,which integrates a piezoelectric nanogenerator (PENG) and a triboelectric nanogenerator (TENG) into a single structure with only two electrodes.The HNG enables enhancement of the electrical output of the nanogenerators.An open-circuit voltage of 280 V and a short-circuit current of 25 μA are achieved by a HNG of 2.5 cmx 2.5 cm in size,superior to the performance of previously reported HNGs.In addition,the energy-conversion process of the HNG relies on the working mechanism of both the PENG and TENG.The polarization direction and doping content of BTO are the two major factors that affect the electrical output.Biomechanical energy harvesting from walking motion or the bending of an arm is also demonstrated.     

Piezoelectric potential in vertically aligned nanowires for high output nanogenerators

In this work we analyze the coupled piezoelectric and semiconductive behavior of vertically aligned ZnO nanowires under uniform compression. The screening effect on the piezoelectric field caused by the free carriers in vertically compressed zinc oxide nanowires (NWs) has been computed by means of both analytical considerations and finite element calculations. We predict that, for typical geometries and donor concentrations, the length of the NW does not significantly influence the maximum output piezopotential because the potential mainly drops across the tip, so that relatively short NWs can be sufficient for high-efficiency nanogenerators, which is an important result for wet-chemistry fabrication of low-cost, CMOS- or MEMS-compatible nanogenerators. Furthermore, simulations reveal that the dielectric surrounding the NW influences the output piezopotential, especially for low donor concentrations. Other parameters such as the applied force, the sectional area and the donor concentration have been varied in order to understand their effects on the output voltage of the nanogenerator.     

The enhanced performance of piezoelectric nanogenerator via suppressing screening effect with Au particles/ZnO nanoarrays Schottky junction

This paper describes a novel strategy to weaken the piezopotential screening effect by forming Schottky junctions on the ZnO surface through the introduction of Au particles onto the surface. With this approach, the piezoelectric-energyconversion performance was greatly enhanced. The output voltage and current density of the Au@ZnO nanoarray-based piezoelectric nanogenerator reached 2 V and 1 μA/cm², respectively, 10 times higher than the output of pristine ZnO nanoarray-based piezoelectric nanogenerators. We attribute this enhancement to dramatic suppression of the screening effect due to the decreased carrier concentration, as determined by scanning Kelvin probe microscope measurements and impedance analysis. The lowered capacitance of the Au@ZnO nanoarraybased piezoelectric nanogenerator also contributes to the improved output. This work provides a novel method to enhance the performance of piezoelectric nanogenerators and possibly extends to piezotronics and piezophototronics.

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Controlled growth of ZnO nanorods on common paper substrate and their application for flexible piezoelectric nanogenerators

A simple and effective method of synthesizing nanorods (NRs) and the ability to control the size and aspect ratio of them are crucial for fabricating nanodevices. In this paper, we present a systematic study of the growth of ZnO NRs on common paper substrates using a hydrothermal approach by adjusting the growth conditions. By a slight variation of the solution concentration and the growth time, significant changes in morphology and size (aspect ratio) of the obtained ZnO NRs have been controlled. Moreover, the piezoelectric power generation from ZnO-paper nanogenerators grown with different precursor concentration and growth time are also investigated. It is found that the morphology and aspect ratio of NRs have significant influence on the piezoelectric behavior. This type of flexible piezoelectric nanogenerator will have potential applications in implantable biosensors and wearable self-powered electronic devices.     

Scanning Probe Study on the Piezotronic Effect in ZnO Nanomaterials and Nanodevices

ZnO nanomaterials with their unique semiconducting and piezoelectric coupled properties have become promising materials for applications in piezotronic devices including nanogenerators, piezoelectric field effect transistors, and diodes. This article will mainly introduce the research progress on piezotronic properties of ZnO nanomaterials investigated by scanning probe microscopy (SPM) and ZnO‐based prototype piezotronic nanodevices built in virtue of SPM, including piezoelectric field effect transistors, piezoelectric diodes, and strain sensors. Additionally, nanodamage and nanofailure of ZnO materials and their relevant piezotronic nanodevices will be critically discussed in their safe service in future nanoelectromechanical system (NEMS) engineering.     

压电式纳米发电机及其混合器件的研究进展

随着化石能源的过度使用和开采,随之而来的能源和环境问题也日益尖锐,而人们对能源的需求不减反增,因此寻求一种新型的绿色可持续能源是非常必要的。环境中的能量十分丰富,因此从环境中收集能量进行转化是十分有前景的方法。压电材料在受到外界作用发生机械变形时,能实现机械能向电能的转化,因此,压电式纳米发电机作为一种潜在的可持续、绿色能源,近年来受到广泛关注。从压电材料的分类入手,结合其制备方法、结构和性能等,对近年来一些研究成果进行了概述,详细评价了不同制备方法、结构对压电式纳米发电机压电性能的影响,并对今后发展进行了展望。     

Fiber/Fabric-Based Piezoelectric and Triboelectric Nanogenerators for Flexible/Stretchable and Wearable Electronics and Artificial Intelligence

Integration of advanced nanogenerator technology with conventional textile processes fosters the emergence of textile-based nanogenerators (NGs), which will inevitably promote the rapid development and widespread applications of next-generation wearable electronics and multifaceted artificial intelligence systems. NGs endow smart textiles with mechanical energy harvesting and multifunctional self-powered sensing capabilities, while textiles provide a versatile flexible design carrier and extensive wearable application platform for their development. However, due to the lack of an effective interactive platform and communication channel between researchers specializing in NGs and those good at textiles, it is rather difficult to achieve fiber/fabric-based NGs with both excellent electrical output properties and outstanding textile-related performances. To this end, a critical review is presented on the current state of the arts of wearable fiber/fabric-based piezoelectric nanogenerators and triboelectric nanogenerators with respect to basic classifications, material selections, fabrication techniques, structural designs, and working principles, as well as potential applications. Furthermore, the potential difficulties and tough challenges that can impede their large-scale commercial applications are summarized and discussed. It is hoped that this review will not only deepen the ties between smart textiles and wearable NGs, but also push forward further research and applications of future wearable fiber/fabric-based NGs.     

High‐Performance Piezoelectric Nanogenerators with Imprinted P(VDF‐TrFE)/BaTiO3 Nanocomposite Micropillars for Self‐Powered Flexible Sensors

Piezoelectric nanogenerators with large output, high sensitivity, and good flexibility have attracted extensive interest in wearable electronics and personal healthcare. In this paper, the authors propose a high‐performance flexible piezoelectric nanogenerator based on piezoelectrically enhanced nanocomposite micropillar array of polyvinylidene fluoride‐trifluoroethylene (P(VDF‐TrFE))/barium titanate (BaTiO₃) for energy harvesting and highly sensitive self‐powered sensing. By a reliable and scalable nanoimprinting process, the piezoelectrically enhanced vertically aligned P(VDF‐TrFE)/BaTiO₃ nanocomposite micropillar arrays are fabricated. The piezoelectric device exhibits enhanced voltage of 13.2 V and a current density of 0.33 µA cm^?2, which an enhancement by a factor of 7.3 relatives to the pristine P(VDF‐TrFE) bulk film. The mechanisms of high performance are mainly attributed to the enhanced piezoelectricity of the P(VDF‐TrFE)/BaTiO₃ nanocomposite materials and the improved mechanical flexibility of the micropillar array. Under mechanical impact, stable electricity is stably generated from the nanogenerator and used to drive various electronic devices to work continuously, implying its significance in the field of consumer electronic devices. Furthermore, it can be applied as self‐powered flexible sensor work in a noncontact mode for detecting air pressure and wearable sensors for detecting some human vital signs including different modes of breath and heartbeat pulse, which shows its potential applications in flexible electronics and medical sciences.