Sb Doping Strategy to Promote Growth and Suppress Defects in Solution-Processed CZTSSe Solar Cells for Improved Optoelectronic Performance

In recent years, Cu 2 ZnSnS 4 (CZTS)-based thin-film solar cells have received extensive attention for the optimization of grain growth and the suppression of defects by cation replacement. In this work, we report for the first time the replacement of stannum (Sn) atoms with antimony (Sb) doped into the lattice by solution treatment. Cu 2 ZnSb x Sn 1– x (S, Se) 4 (0 ≤ x ≤ 0.2) (CZTSSSe) thin films are synthesized on soda lime glass substrates by sol–gel and two-step annealing techniques. The Sb doping strategy and the structural, morphological, optical, and electrical properties of CZTSSSe films are described. According to SEM results, it was found that the CZTSSSe ( x = 0) thin film is composed of nanoscale small grains, and the right amount of Sb doping encourages grain growth, allowing for the fabrication of dense CZTSSSe films with bigger grain sizes and fewer holes. When x = 0.10, the best outcomes were attained. Sb successfully replaces the Sn sites, which decreases the production of harmful defects associated with Sn and enhances the electrical properties of thin films to improve carrier mobility. The open circuit voltage ( V OC ) of the CZTSSSe ( x = 0.10) device increased by 29 mV as compared to the pure Cu 2 ZnSn(S, Se) 4 (CZTSSe) device, and its power conversion efficiency (PCE) increased from 5.06 to 6.82%. These outcomes exhibit the potential of Sb in enhancing the PCE of CZTSSe-based devices.