Photoinduced charge transfer processes at semiconductor electrodes and particles

Abstract

In contrast to reactions at metal electrodes, charge transfer processes at semiconductor electrodes can be controlled by light excitation if minority carriers are involved. Since electron and hole transfer always occur via one of the energy bands, valuable information on the energy parameters determining the reaction rates can be obtained. In the present paper, models of the charge transfer processes at semiconductor electrodes are presented, and the kinetics of various reactions in the dark and under illumination are discussed in detail. During the last decade it has become very popular to investigate photoinduced charge transfer reactions at small semiconductor particles, i.e. at micoroheterogeneous systems, because of the large surface area. Here, various fundamental processes in suspensions or colloidal solutions are compared with corresponding reactions at extended electrodes. Finally, several applications of photoinduced reactions at semiconductor electrodes and particles are briefly described.