Significant enhancement of photo-physicochemical properties of Yb doped copper oxide thin films for efficient solid-state solar cell

Abstract

Pure and Ytterbium (Yb) doped Copper oxide (CuO) thin films with different wt% (0, 1, 2, 3, 4, and 5) are deposited on glass substrates using chemical spray pyrolysis technique at 300 °C and their performances in heterojunction solar cell are examined here. The structural characterization reveals the monoclinic crystal structure and an increase in crystallite size is observed for 3 wt% Yb doped CuO. All the films show optical absorption in the UV–Vis region and 3 wt% has a higher absorption coefficient. The generation of self-assembled one-dimensional (1D) microrod like structure is observed for 3 wt% Yb doped CuO sample. The 3 wt% Yb doped CuO film exhibits higher carrier concentration (6.91 × 1019 cm−3) and electrical conductivity (0.58 S cm−1). All the films perform single semicircle impedance nature and smaller radius semicircle for 3 wt%, which indicates low electrical resistivity. The higher dark current (0.5 mA) and photoresponse (0.62 mA) are observed for 3 wt% of Yb doped CuO film compared with pure and other wt%. The solar cell power conversion efficiency of 0.37% and 1.8% is observed for pure and 3 wt% of Yb doped CuO respectively. It is concluded that 3 wt% of Yb doped CuO thin film can be used as an efficient absorber layer for fabricating heterojunction solar cell.