Comprehensive Theoretical and Device-Level Investigation of Lead-Free K3TlBr6 Perovskite for High-Efficiency Solar Cell Applications

This study makes a pioneering contribution by conducting the first comprehensive investigation of the lead-free perovskite compound K3TlBr6 for high-efficiency solar cell applications. It integrates first-principles Density Functional Theory (DFT) and device-level SCAPS-1D simulations to assess the material’s electronic, mechanical, optical, and photovoltaic properties. Key findings reveal that K₃TlBr₆ exhibits a direct band gap, mechanical flexibility, strong UV-visible light absorption, and robust thermal and defect tolerance. The optimized device configuration achieves a power conversion efficiency (PCE) of 22.61%, confirming its viability as an eco-friendly, stable absorber layer for next-generation solar cells. This work bridges the gap between material properties and device performance, offering a valuable framework for future experimental development of K3TlBr6-based photovoltaics.