LAUSR

Abstract Solar absorbing layer is one of the most important components of the whole structure of the photo-sensitive devices. In this context, improving the absorber material parameters is very crucial to obtain the highly efficient solar cells. Specifically, the structure and surface morphology properties influence the device parameters, profoundly. Herein, we reported copper-based chalcogenide Cu2CoSnS4 (CCTS) thin films by the solution-assisted route on the glass substrates. High crystalline samples were obtained by manipulating the chemical composition of the CCTS. The phase purity of the thin films were confirmed by means of non-destructive XRD and Raman measurements. The elemental mapping showed homogeneous element distribution which was ensured for all the thin film samples. Besides, remarkable morphological changing depended on the Cu/Co ratios was observed. The grain size and surface topography are important parameters for the carriers transition. The enhanced grain size was observed by changing of the stoichiometry of absorber. It was also observed that the roughness of material surface increased due to the growth of the grain size. Optical analyses showed the direct band gap varying from 1.29 to 1.22 eV depend on the Cu/Co ratios that are close to optimum value of band gap energy for the solar cell applications.