Comparative study of effective photoabsorber CuO thin films prepared via different precursors using chemical spray pyrolysis for solar cell application

Abstract

Copper oxide (CuO) thin film is a promising material used as a photo-absorber layer in solar cell application due to its narrow bandgap, low cost and high abundance. In this work, the CuO thin films have been prepared using various source materials such as Cu(NO3)2·3H2O, CuCl2·2H2O and Cu(CH3COO)2·H2O by chemical spray pyrolysis technique. The XRD result shows an increased crystallite size for Cu–N compared with Cu–Cl and Cu–A films. Good optical absorption in the visible region is observed for all CuO films and Cu–N film illustrates high absorption coefficient in the order of 5.7 × 105 cm−1. From SEM analysis, flake like morphology is observed for Cu–N and Cu–A films. The good electrical property i.e. high conductivity (0.0611 S cm−1) and carrier concentration (2.287 × 1017 cm−3) is observed for Cu–N films. All CuO films exhibit a single semicircle impedance nature and smaller diameter of semicircle corresponding to Cu–N film indicates low electrical resistivity present in the sample. From I–V measurement, it is observed that the high current for Cu–N (16.6 µA) than Cu–Cl (2.3 µA) and Cu–A (10.7 µA). All CuO films are photo-responsive under solar light exposure, which is due to high absorption coefficient that leads to higher photocurrent (20.5 µA) for Cu–N film. The best solar cell performance is obtained for Cu–N film which shows an efficiency of 0.31%. From the above results, we conclude that Cu–N is an optimum precursor for fabricating CuO based thin film solar cell.