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| Imaging of triboelectric charge distribution induced in polyimide film by using optical second-harmonic generation: Electronic charge distribution and dipole alignment |
| 2019-06-01
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| CAS Key Laboratory of Theoretical Physics | | Institute of Theoretical Physics | | Chinese Academy of Sciences | | Seminar | | Title 题目 | Imaging of triboelectric charge distribution induced in polyimide film by using optical second-harmonic generation: Electronic charge distribution and dipole alignment | | Speaker 报告人 | | | Affiliation 所在单位 | | Tokyo Institute of Technology, Japan | | | Date 日期 | | | Venue 地点 | Main building 322 | | Abstract 摘要 | Triboelectric generation is attracting much attention as an eco-friendly power source. Available power density of triboelectric generators is increasing and it is reaching as high as 30 mW/cm2. Accordingly, the related application research field is growing. Research and development of new materials is very active in the world, where conception idea of triboelectric series is well-utilized to produce high performance triboelectric generators. However, charge generation, charge separation, charge decay, and other charging processes are still unclear owing to the complexity of electrification. Excessive electronic charges induced on a film surface by rubbing is a main origin, but dipolar alignment induced by rubbing and others also make a significant contribution. It is difficult to identify the origin of triboelectric charges by using only electrical measurement such as surface potential measurement, even though the state-of-art scanning probe microscopes (SPM) are available for visualizing surface potential distribution on nanometer scale. On the other hand, by using optical second-harmonic generation (SHG) microscope, it is possible to identify the source of triboelectric charges. Using polyimide film negatively charged by rubbing with a cotton belt. The excessive electronic charges were imaged using the probe laser wavelength of 1140 nm (SHG wavelength 570 nm), whereas the aligned dipoles were visualized by choosing the laser wavelength of 570 nm (SHG wavelength 285 nm). Combining the visualized two images showed that dipolar alignment region with 10 micro-meter width was induced on rubbed polyimide surface, and at the same time excess electronic charges were generated in that region. We conclude that dipolar alignment and electronic charging are main contributors, and the interaction between the two contributors plays an essential role in triboelectrification. | | Contact Person 所内联系人 | 欧阳钟灿 |
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