Electrochemical growth and characterization of a p-Cu2O thin film on n-ZnO nanorods for solar cell application

Abstract

Heterostructural p-Cu₂O/n-ZnO solar cells are fabricated by the consecutive electrochemical deposition of an n-ZnO nanorod layer, followed by a p-Cu₂O layer on a transparent conductive substrate. The growth parameters, growth temperature and time of applied potential, which determine the crystalline structure and film thickness of Cu₂O, are fine-tuned to investigate their effects on the performance of heterojunction solar cells. From XRD and SEM analyses, the best crystalline quality and the optimum Cu₂O film thickness are accomplished at the potential of −0.4 V and the growth temperature of 60 °C for 10 min. In addition, the electrolyte concentration plays an important role in the optical absorbance of Cu₂O film, which significantly exhibits two-time enhancement as adjusting the CuSO₄ concentration of 0.4 M to 0.02 M. The best performance of the heterojunction cell is able to achieve the conversion efficiency of 0.33% with V_oc, J_sc, and FF being 0.15 V, 7.03 mA cm⁻², and 0.33, respectively. Hence, this study demonstrates that the proposed strategy to improve the solar cell performance realized by electrochemical deposition has the potential to produce cheap and environmentally friendly solar cells.