Photocurrent Enhancement in a Photo-electrochemical Cell with Improved Cu/n-Cu2O Photoelectrode by Reducing the Surface States on n-Cu2O as Trapping Centers

n-Cu2O photoelectrodes were fabricated by boiling a copper plate for 60 min in a CuSO4 (10−3M) solution. A photocurrent enhancement was found in the photoelectrochemical cell after the potential sweeping of the samples in the presence of water as the electrolyte. The reason for the photocurrent enhancement was found by depletion of the surface states on n-Cu2O at electrolyte interface by potential sweeping.