The radical intermediates generated during photoinduced electron transfer processes in semiconductor systems, such as AgX, TiO₂, ZnO, WO₃, CdS, CdS modified with diethyl dithiocarmate or β-cyclodextrin, and CdS-ZnS and CdS-TiO₂ coupled semiconductors, etc., have been investigated.

The radical intermediates form by electron transfer either from the adsorbed molecules in their excited states to semiconductor or from the excited semiconductor to the adsorbed molecules.  The results not only provide valuable information for deep understanding the mechanisms and the kinetics of the photoinduced electron transfer processes, such as sensitization, supersensitization and desensitization in photography, degradation of pollutants and solar energy utilization, but also probably furnish a basis for developing new materials, new systems and new methods in photography, solar energy conversion and environment treatment.