报告人： 张青教授 新加坡南洋理工大学

　　报告时间：2023年6月25日10:00

　　报告地点：科研楼一楼报告厅

　　联系人： 翟俊宜研究员

　　About the speaker

　　Qing Zhang is a professor at Centre of Micro-/Nano-electronics, School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore. His research interests cover nanomaterials and nano/micro-electronic devices, etc. Very recently, he is interested in mechanical to electric power conversion through chemical potential difference.

　　Abstract

　　When semiconductors and\or metals with different chemical potentials are in contact or electrically connected, electrons must flow from the higher chemical potential material to the lower one to achieve thermal equilibrium, leading to electrification between the two materials and formation of the p-n junctions and\or Schottky junctions. When one of the materials is moved against the other, electron-hole pairs are generated at their contacted surfaces and then swept out of the junctions by the built-in electric fields, generating a current in the circuit that connects to the backsides of the two materials. This is the tribovoltaic process. Otherwise, one of the materials is repeatably in contact and separated with the other, leading to electrons pumped to the external circuit, creating one polarity dominated transient current. Both processes could fulfil mechanical to electric power conversion through chemical potential difference.

　　In this presentation, I shall highlight a novel mutual interaction between two pairs of electrodes. In each pair, the two electrodes are of distinct chemical potentials and electrically connected. There is no any electrical connection between the two pairs. When one pair of electrodes is moved with respect to the other pair relatively, electrical currents are induced in each pair. The induced currents provide us with the information of the relative motions, including relative motion speed, vibrations, rotations, eccentricity, transient gap width between the two pairs, etc. Most importantly, the induced current can be amplified by superposition of built-in potential difference. This mutual interaction could find a broad application in self- powered detection of relative motions, vibrations, etc.