Interfacial Bond Engineering in Antimony Selenosulfide Solar Cells via Methylammonium Lead Bromide Perovskite Particles as Hole Transport Layer

Antimony selenosulfide, Sb2(S,Se)3, materials have emerged as a prominent research hotspot in energy and optoelectronics fields, owing to their tunable band gap, excellent stability and one-dimensional crystal structures. Sb2(S,Se)3 solar cell devices usually adopt layered device structure where the hole transport layers (HTLs) play critical roles in affecting the device efficiency, operational stability, and charge carrier transport capabilities. Despite considerable advances in Sb2(S,Se)3 photovoltaics, their development remains constrained by an efficiency-stability trade-off primarily stemming from interfacial defects and thermal degradation of conventional HTLs such as Spiro-OMeTAD, which exhibit rapid performance decay under ambient conditions. Herein, methylammonium lead bromide (MAPbBr3) films are strategically designed as HTLs, leveraging their covalent Pb-S(Se) and Sb-Br interfacial bonds with Sb2(S,Se)3 to enhance charge extraction efficiency and passivate interfacial defects. Ultraviolet photoelectron spectroscopy (UPS) analysis reveals a cliff-like band alignment at the Sb2(S,Se)3/MAPbBr3 heterojunction interface, which effectively suppresses interfacial electron recombination. Furthermore, we demonstrate a record power conversion efficiency (PCE) of 9.37% in optimized solar cells, which represents the highest reported value for antimony chalcogenides/perovskite heterojunction solar cells. This study proposes a class of perovskite based HTLs that enables efficient interfacial band alignment, establishing a new paradigm for interface engineering in high-performance photovoltaic devices.