Photochemical processes in monomolecular dye layers on SnO2

Abstract

The primary step in the charge-transfer process between a monomolecular dye layer and SnO₂ has been studied. An attempt is made to correlate the charge transfer with one of the energy levels in the dye. According to absorption and emission measurements, dimers and higher aggregates were formed at increasing dye concentrations within the monolayer. The formation of excimers, which are quenched by SnO₂, is postulated. It can be proved that the charge transfer, detected as a photocurrent across the interface, is essentially that of the monomer singlet state to the conduction band of SnO₂.