Photoelectrochemical kinetics and the relationship between photovoltage and light intensity for metal photoelectrodes coated with adsorbed dyes

It is shown that the inclusion of an excited state step in parallel with a ground state charge-transfer step for a photoelectrode comprising a metal coated with an adsorbed dye leads to a different photovoltage-light intensity expression from that previously derived by Hillson and Rideal[4] who assumed simple displacement of the ground state charge-transfer process by light. The Hillson and Rideal expression is shown to be a valid approximation when illumination of the electrode only slightly perturbs the electrodic charge-transfer reactions.