Enhancement in photoelectrochemical performance of ZnO nanoparticle–based photoelectrodes with incorporation of Cu dopant source

Pristine- and copper-doped ZnO thin films with various concentrations were deposited on tin-doped indium oxide–coated glass substrates using the sol–gel method followed by the spin-coating technique. All the deposited samples were further processed with annealing at 450 °C with the aim of decreasing defects in the sample. Structural properties revealed that films are polycrystalline in nature and morphological study represented an increase in particle size with increasing Cu-doping concentration. The absorption data show band gap narrowing and electrical analysis shows an increase in conductivity and carrier concentration with optimized Cu-doping concentration. This study shows that sol–gel–derived Cu-doped ZnO thin films show low band gap, low electrical resistivity, and high transmittance and can be used for optoelectronic devices. Furthermore, films were tested for photoelectrochemical performance in 0.5 M Na₂SO₄ electrolyte solution. An optimum amount of Cu dopant with ZnO nanoparticles (NPs) has shown enhanced photocurrent density which six times enhanced and increased photoconversion efficiency compared to those of the bare ZnO NPs.