Highly efficient double halide perovskite for solar cell devices with DFT and SCAPS 1D analysis

Advancing sustainable photovoltaic technologies depends greatly on the development of high-performance perovskite solar cells (PSCs), and new materials continue to provide promising opportunities for improving device efficiency. This research investigates the double perovskite compound Cs2TlRhI6 as a potential light-harvesting material through first-principles calculations and device-level simulations. The material has a direct bandgap of 1.12eV, a refractive index of about 3.1, low reflectivity (below 30%), and strong absorption in the visible range, all of which support its potential for photovoltaic applications. Furthermore, implementing our absorber in an optimized device structure, employing Cu2O as the HTL and IGZO as the ETL, achieves a PCE of 25.78%, with a JSC of 40.53 mA/cm2, a VOC of 0.79 V, and a FF of 80.40%. Temperature analysis indicates a slight reduction in performance at high temperatures, revealing good thermal stability of the device. This work opens up Cs2TlRhI6 as a promising and structurally stable material for future PSCs.