Studies on the kinetics of interfacial electron transfer sensitized by colloidal CdS

Plash photolysis was used to study photobleaching of colloidal CdS particle s with the controlled size. The rate constant of the photobleaching relaxat ion was found to depend on the size of the colloidal particles, an increase of the particle size resulting in a decrease of the rate constant. The inf luence of various electron accepters on the photobleaching relaxation kinet ics was investigated too. The addition of well adsorbing acceptor molecules decreases the initial amplitude of photobleaching and practically does not change the rate constant of the photobleaching relaxation. The photobleach ing decay kinetics remains unchanged compared to the photobleaching relaxat ion kinetics of pure CdS. The addition of acceptor molecules with the small adsorption constant results in an increase of photobleaching relaxation ra te constant, while the initial amplitude of photobleaching remains unchange d. Moreover, in the last case the photobleaching decay kinetics became expo nential. (C)2000 Published by Elsevier Science S.A. All rights reserved.