Photostable Cu2O photoelectrodes fabricated by facile Zn-doping electrodeposition

Abstract

Cu2O is a promising semiconductor material for photoelectrochemical (PEC) cells owing to element abundance, nontoxicity, good mobility and broad visible-spectrum light absorption. However, its practical applications are always limited by poor photostability. In this work, we report a facile Zn-doping electrodeposition approach to highly stable Cu2O photoelectrodes, which allows tailoring compositions and crystalline structures by simply altering the usage of ZnSO4 solution. As a result, the optimal Zn-doped photoelectrode demonstrates a high stability of 92.97%. The Zn cation dopant contributes to improving carrier concentration and charge transfer; however, too high concentration of Zn doping may induce charge recombination to lower initial photocurrent density. Meanwhile, the Zn doping can suppress the oxidation of Cu2O to CuO so that the photocurrent density maintains in a limited oscillation mode rather than undergoes an exponential degradation. This work represents a step toward the fabrication of low-cost, stable and visible-responsive photoelectrodes.