Optimization of preparation conditions and design of device configurations for Cu3AsS4 solar cells: a combined study of first-principles calculations and SCAPS-1D device simulations

Abstract

Former studies have investigated the band structure and optoelectronic properties of Cu₃AsS₄ and suggested that it is a promising photovoltaic (PV) absorber. However, its power conversion efficiency (PCE) from experiments is still unsatisfactory and detailed experimental optimization strategies are lacking. Here, combining first-principles calculations and SCAPS-1D device simulations, we have systematically studied the optoelectronic and defect properties of Cu₃AsS₄ to find the suitable growth conditions and have performed various device simulations by adjusting the constituent layers to optimize the device configuration of the Cu₃AsS₄ solar cell. Our results demonstrated that the defect and hole concentrations can be regulated to a reasonable range as the PV absorber in metal-rich and S-poor growth environments with a low growth temperature of 500 K. Owing to the large cliff-like conduction band offset between the traditional buffer layers CdS and Cu₃AsS₄, the open-circuit voltage loss is large and the corresponding PCE is low. The PCE can be improved by adopting the new buffer layers with low electron affinity. The corresponding n-type transparent electrode is further optimized. Finally, the solar cell with the configuration of FTO/WO₃/Cu₃AsS₄/Mo is suggested and its PCE can reach an optimal value of 17.82%.