Photoluminescence and photoelectrochemical properties of the spray deposited copper doped zinc oxide thin films

Copper incorporated zinc oxide (CuZnO) thin films were synthesized onto the glass and tin doped indium oxide (ITO) coated glass substrates at 450 °C by simple and cost-effective spray pyrolysis technique (SPT). The X-ray diffraction (XRD) patterns confirmed the polycrystalline nature of the films having hexagonal crystal structure. A compact and granular morphology was observed for all deposited films. The absorption edge of the CuZnO films showed a red shift, meaning that the optical band gap energy decreases as copper doping concentration increases. The room-temperature photoluminescence (PL) spectra of CuZnO films revealed the ultraviolet (UV) near band edge emission peak at ~373 nm and the defect related level emission at ~447 nm. Furthermore, films deposited onto conducting ITO coated glass substrates were tested for their photoelectrochemical (PEC) performance in 0.5 M Na2SO4 electrolyte solution. The fill factor (FF) and open circuit voltage (Voc) values were improved for CuZnO films.