ABSTRACT
This chapter addresses the photophysical and photochemical properties of nanomicrometer size semiconductor colloids and the factors that control the photo-catalytic efficiency. Microencagement of semiconductor particles in an organized medium controls not only the morphology but also the photocatalytic properties of the semiconductors. The majority of the charge carriers in semiconductor clusters recombine by the nonradiative route because of the strong coupling wave functions for the trapped electrons and holes to the lattice vibrations. The dependence of the emission lifetime on temperature has been treated by theoretical multiphonon rate expressions. A decrease in the emission lifetime of semiconductor colloids is observed when an electron acceptor or a surface modifier is adsorbed onto the semiconductor surface. Characterization of photochemical events that lead to the semiconductor corrosion is important for improving the photostability of the colloidal semiconductor system. The interaction between the two semiconductor systems can be probed with photophysical and photochemical properties.
