Next-Generation Dual-Absorber Design Using Ca₃AsI₃ and Sr₃PBr₃ Perovskites for High-Performance Solar Cells.

This work investigates four perovskite solar cell (PSC) architectures to evaluate how material selection, absorber thickness, defect and acceptor densities, interface quality, and temperature affect device efficiency. Energy band alignment analyses were performed to enhance charge separation and extraction. Among the designs, the dual-absorber structure (FTO/CdS/Ca₃AsI₃/Sr₃PBr₃/MoO₃/Au) achieved the highest power conversion efficiency (PCE) of 29.77% with each absorber layer at 1.0 μm. Single-absorber devices based on Sr₃PBr₃ and Ca₃AsI₃ reached 20.71% and 19.75%, respectively. Increased defect density was found to significantly reduce performance, whereas controlled acceptor concentration and interface optimization improved both efficiency and stability. Temperature-dependent analysis revealed a general decline in PCE with increasing temperature, though the dual-absorber device maintained superior thermal stability. These results underscore the importance of dual absorbers, optimized thickness, and effective hole transport layers in advancing the efficiency and durability of high-performance PSCs.