PHOTOINDUCED CHARGE-TRANSFER BETWEEN CARBON AND SEMICONDUCTOR CLUSTERS - ONE-ELECTRON REDUCTION OF C-60 IN COLLOIDAL TIO2 SEMICONDUCTOR SUSPENSIONS

UV excitation of TiO2 colloids in ethanol leads to the trapping of holes and electrons. Photoelectrochromic effects are seen as these trapped charge carriers exhibit strong absorption in the red and UV regions. Electron or hole scavengers such as O-2 or triethanolamine can selectively scavenge these stored charge carriers. A simple photocatalytic method has been presented to carry out one-electron reduction of C-60 in 50/50 (v/v) benzene/ethanol. The charge transfer between the excited TiO2 semiconductor colloid and C-60 occurs With a quantum efficiency of 24%. The dependence of observed quantum yield of C-60- formation on the concentration of C(60)shows the existence of an association equilibrium between the two clusters (K-app = 57 500 M(-1)).