Electrodeposition and characterization of Cu2O thin films using sodium thiosulfate as an additive for photovoltaic solar cells

Cuprous oxide (Cu2O) thin films have been grown by electrodeposition technique onto ITO-coated glass substrates from aqueous copper acetate solutions with addition of sodium thiosulfate at 60 degrees C. The effects of sodium thiosulfate on the electrochemical deposition of Cu2O films were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were obtained at -0.58 V vs. SCE and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and optical, photoelectrochemical and electrical measurements. X-ray diffraction results indicated that the synthesized Cu2O films had a pure cubic phase with a marked preferential orientation peak along (200) plane and with lattice constants a = b = c = 0.425 nm. FTIR results confirmed the presence of Cu2O films at peak 634 cm(-1). SEM images of Cu2O films showed a better compactness and spherical-shaped composition. Optical properties of Cu2O films reveal a high optical transmission (>80%) and high absorption coefficient (alpha > 10(4) cm(-1)) in visible light region. The optical energy band gap was found to be 2.103 eV. Photoelectrochemical measurements indicated that Cu2O films had n-type semiconductor conduction, which confirmed by Hall Effect measurements. Electrical properties of Cu2O films showed a low electrical resistivity of 61.30 Omega.cm(-1), carrier concentration of -4.94 x 10(15) cm(-3) and mobility of 20.61 cm(2).V-1.S-1. The obtained Cu2O thin films with suitable properties are promising semiconductor material for fabrication of photovoltaic solar cells. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.