The charge carrier conduction mechanism plays an important role in determining efficient Perovskite Solar Cells (PSCs), one of which lies in the Hole Transport Layer (HTL). Nowadays, the organic Spiro-Ometad HTL has been widely used in conventional PSCs, but the cell performance is still hindered and limited by the ambient humidity stability issue. Herein, a solid-state Molybdenum Trioxide (MoO₃) has been employed as the HTL in Pb-free PSCs. To comprehend its functional behaviour, a systematic study through the optimization of several critical parameters was carried out using SCAPs software. The high Power Conversion Efficiency (PCE) was achieved reaching 20.3% under AM 1.5 illumination, proving the high potential of MoO₃ as HTL in PSC. With optimized parameters, the distinctive solid-state MoO₃ has stood out among the top HTLs in PSC technology.
