Design of Homojunction Perovskite Solar-Cell Devices Without Hole-Transport Layer

Perovskite solar cells (PSCs) that lack a hole transport layer (HTL) attract considerable interest because of their straightforward design. This study utilizes the inherent self-doping properties of perovskite to propose a novel homojunction design combining n-FASnI₃ and p-FASnI₃ for efficient HTL-free PSCs. The internal factors affecting the device, such as defect density, electron affinity, bandgap, and doping concentration, are investigated using the solar-cell capacitance simulator (SCAPS-1D). An interfacial defect layer (IDL) is introduced between n-FASnI₃ and TiO₂ to mitigate recombination at interfaces, with related parameters also optimized. Furthermore, the influence of various metal electrodes on PSC performance is examined. Ultimately, the cell achieves an optimized power-conversion efficiency of 30.52%. These findings highlight the bright prospects of homojunction-based HTL-free PSCs. They simplify device structure and production processes while preserving high efficiency. This research lays the groundwork for future industrial applications of HTL-free PSCs in the field of photovoltaics.