Stability of a Cu2O photoelectrode in an electrochemical cell and the performances of the photoelectrode coated with Au and SiO thin films

The photoresponse and stability of Cu2O films have been examined. Thermodyn amic calculations showed that, for Cu2O, there exists a region of chemical stability potential between -0.218 and -0.489 V(S.C.E) for oxidation and re duction potential, respectively. In an aqueous solution, a deterioration in power output occurs at a rate of 50% per day. To stabilize the photocurren t, thin deposits of Au and SiO films onto Cu2O electrodes have been studied . For the Au deposition, the photocurrent was either quenched or reduced. F or the SiO deposited photoelectrode, its effect was to decrease the quantum efficiency of Cu2O. However, the deposition does not affect the band gap a t 2.11 eV (which ensued for an uncoated sample). (C) 1999 Elsevier Science Ltd. All rights reserved.