PHOTOINDUCED VOLTA POTENTIAL IN A PORPHYRIN MONOLAYER

Abstract— When spread on an oxidizing aqueous subphase, an amphipathic basket handle zinc porphyrin (P) monolayer gives rise to a photoinduced Volta potential change. This surface photopotential is interpreted on the basis of an interfacial electron transfer in the interphase; upon light excitation, electrons are transferred from the chromophores in the monolayer to electron acceptors diffusing from the subphase. A kinetic model for charge separation and stabilization is proposed to account for the influences of the electron acceptor concentration, the pH of the subphase and the light intensity.