Wu Hao, Mendel Niels, van den Ende Dirk, Zhou Guofu, Mugele Frieder
Physics of Complex Fluids, Faculty of Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500AE, The Netherlands.
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China.
Phys Rev Lett. 2020 Aug 14;125(7):078301. doi: 10.1103/PhysRevLett.125.078301.
We use a combination of high-speed video imaging and electrical measurements to study the direct conversion of the impact energy of water drops falling onto an electrically precharged solid surface into electrical energy. Systematic experiments at variable impact conditions (initial height; impact location relative to electrodes) and electrical parameters (surface charge density; external circuit resistance; fluid conductivity) allow us to describe the electrical response quantitatively without any fit parameters based on the evolution of the drop-substrate interfacial area. We derive a scaling law for the energy harvested by such "nanogenerators" and find that optimum efficiency is achieved by matching the timescales of the external electrical energy harvesting circuit and the hydrodynamic spreading process.
我们使用高速视频成像和电学测量相结合的方法，来研究落在预充电固体表面的水滴的冲击能量直接转化为电能的过程。在可变冲击条件（初始高度；相对于电极的冲击位置）和电学参数（表面电荷密度；外部电路电阻；流体电导率）下进行的系统实验，使我们能够基于液滴-基底界面面积的演变，在无需任何拟合参数的情况下定量描述电响应。我们推导了此类“纳米发电机”收集能量的标度律，并发现通过匹配外部电能收集电路的时间尺度和流体动力学铺展过程可实现最佳效率。
