Next-generation dual absorber solar cell design with Ca3AsI3 and Sr3PBr3 perovskites and MoO3 HTL achieves superior efficiency above 29%

Abstract

This research explores the photovoltaic performance of four different perovskite solar cell (PSC) architectures, with emphasis on how material selection, absorber layer thickness, defect and acceptor densities, interface imperfections, and temperature fluctuations influence device efficiency. Energy band alignment analyses were conducted to enhance charge separation and extraction. Among the configurations, the device incorporating dual absorbers Sr₃PBr₃ and Ca₃AsI₃ exhibited the highest efficiency. Analysis of absorber thickness effects indicated maximum power conversion efficiencies (PCEs) of 20.71% for device-i (FTO/CdS/Sr₃PBr₃/Au) and 19.75% for device-ii (FTO/CdS/Ca₃AsI₃/Au) at a thickness of 1.0 μm. In contrast, device-iv (FTO/CdS/Ca₃AsI₃/Sr₃PBr₃/MoO₃/Au), which employed both a dual-absorber design and a MoO₃ hole transport layer (HTL), achieved an optimal PCE of 29.77% with each absorber layer also at 1.0 μm thickness. The investigation into defect densities revealed that increased defect levels significantly diminished performance. Device-iv stood out for its enhanced stability and efficiency, resulting from fine-tuned acceptor density and effective interface defect mitigation. Temperature analysis showed a general decline in efficiency with increasing temperature, though device-iv maintained relatively higher thermal stability. Overall, the study highlights the critical role of dual absorber layers, optimized geometries, effective HTLs, and minimized defect concentrations in advancing the efficiency and durability of high-performance PSCs.