Effect Of Cui Layer On Photoelectrochemistry Of Cu2o Films

Thin CuI layer has been deposited on the electrodeposited Cu2O film through adsorption I- ions in 2 mM KI at room temperature and pH 3 and its effect on the photoelectrochemical properties of Cu2O has been studied. The electrodeposited Cu2O shows (100) preferential orientation and the chemical deposited CuI shows (111) preferential orientation. XPS results show that the Cu+ valence state dominated on the surface of Cu2O/CuI electrode instead of Cu2+ valence state dominated on the surface of Cu2O electrode. With optimum thickness of CuI layer, the photoelectrochemical response for Cu2O/CuI electrode is largely enhanced. The mechanism for the improvement of the photoresponse has been studied and could be due to positive shift of flatband, longer photogenerated electron lifetime, better charge transfer and less charge recombination for the Cu2O/CuI electrode. (C) 2017 The Electrochemical Society. All rights reserved.