Introducing Spin‑coated ZnO Anti‑reflection Coating for CdS/CdTe Solar Cells

Abstract

Second-generation solar cells, commonly known as thin-film solar cells, have emerged as promising alternatives to traditional silicon-based first-generation photovoltaic cells. The superstrate configuration is the most widely used structure for constructing thin-film solar cells. Nevertheless, light reflection from the front cover glass surface significantly contributes to energy losses in thin-film solar cells. In this study, a ZnO anti-reflection (AR) coating was introduced using the spin coating technique on a glass/FTO/CdS/CdTe/Cu/Au substrate to improve the power conversion efficiency of the solar cell by reducing front-surface reflectance. The ZnO layer deposited at 3000 rpm in 15 s showed the minimum reflectance and higher transmittance over a wavelength range of 500–900 nm. Further, the thickness of the film under optimal conditions was 63.32 nm, which is compatible with the ideal theoretical AR coating thickness of 65 nm. Comparing the device performance of the CdS/CdTe solar cell with and without AR coating, all tested devices showed an average short-circuit current density improvement of 6.8% and overall enhancement in power conversion efficiency of 9.3%.