Investigation of Electron-Transfer Process on Photoexcited Heterogeneous Interface and Its New Application

点击翻译按钮获取中文摘要

It is important to investigate the mechanism of reactions on photoexited semiconductor. In this study, we have employed STM (scanning tunneling microscopy) and a dynamic potential pulse technique as new methods. The following results have been obtained. (1) We built a STM instrument specially designed for observation of semicondoctor-solution interface. A preliminary observation gave an atomic image of HOPG. High-quality images Of MoS_2 was also obtained by STM. (2) A dynamic potential pulse technique has been used to explore the controlling factors of the charge transfer mechanism at semiconductor/electrolyte junction. Potential pulses were applied in the order of nanoseconds to a n-SiC single crystal electrode in various redox electrolytes. (3) High resolution images were obtained on heterogenious interface by a new method of photoelectro chemistry. (4) Activity of photochemical reaction on the photoexcited surface of a semiconductor was applied to kill cancer cells. A typical cancer cell, HeLa cell was killed by photoexcited TiO_2 ultrafine particles. TiO_2 particles modified by hematoporphyrine also showed a good activity.