A PHOTOELECTROCHEMICAL EFFECT AT THE INTERFACE OF IMMISCIBLE ELECTROLYTE-SOLUTIONS

A photoelectrochemical effect (i.e. the generation of a photocurrent or photopotential) was found upon irradiation of an ITIES (aqueous solution of NaCl/1,2-dichloroethane solution of tetrabutylammonium tetraphenylborate), when the organic solution contains an electron donor and an electron acceptor. A photochemical reaction in the organic solution yields ionic species which are transferred into the aqueous phase and produce an electric current across the interface. Two kinds of photochemical systems were used: protoporphyrin+quinones (excitation 540-580 nm) and quinones + tetraphenylborate (excitation 313-365 nm), in which the charge carriers are of different nature. The photocurrent quantum yield lies within the range 10-3-10-1 and depends on the structure of the quinone and the potential drop at the interface. A mathematical theory of the charge phototransfer across the liquid/liquid interface is developed on the basis of the diffusion kinetics. © 1990.