Preparation of Semiconductor Films with High Photocatalytic Activity and Its Application to Organic synthesis

通过对偶氮苯在甲醇溶液中真空蒸发TiO_2膜电极上合成2-苯基吲唑的分析，发现小颗粒半导体膜的使用是n型半导体上发生氧化还原偶联反应的关键因素，同时发现某些刘易斯碱，特别是醇盐离子，本文提出了一种新的沉积CdS薄膜的方法，该方法将化学过程和电化学过程相结合，利用溶液过饱和的原理沉积CdS薄膜。已经发现由此获得的膜由小颗粒组成，并且表现出高的光电能量转换效率。

We have found through the analyzes of 2-phenylindazole synthesis from azobenzenes occurring on a vacuum-evaporated TiO_2 film electrode in methonolic solution that the use of semiconductor films composed of small particles is a crucial factor for oxidation-reduction coupled reaction to take place on n-type semiconductors.We have also found that some Lewis bases, especially alkoxide ion, in solution effectively contribute to the stabilization of CdS electrode against its photocorrosion.A novel method, combining chemical and electrochemical processes and involving a principle of supersaturation of the solution, has been developed for the deposition of CdS films. Films thus obtained have been found to be composed of small particles and exhibit high light-to-electrical energy conversion efficiency.