Two-Dimensional Perovskite Nanosheets: Synthesis and Advances in Solar Cell Applications

Aiming at the prominent bottleneck of poor environmental stability for three-dimensional perovskite solar cells, two-dimensional (2D) perovskite nanosheets have attracted widespread research attention owing to their unique layered crystal configuration, excellent optoelectronic performance and intrinsically enhanced moisture-thermal stability. This paper firstly introduces three typical crystal phases (RP, DJ and ACI) of 2D perovskites and their tunable optoelectronic properties originating from quantum confinement effect. Then it summarizes four mainstream synthesis approaches including hot-injection, ligand-assisted reprecipitation, chemical vapor deposition and exfoliation, and discusses how experimental parameters modulate material morphology. Furthermore, its photovoltaic application strategies are elaborated, covering direct usage as light-absorbing layers, 2D/3D heterojunction interface engineering, as well as efficiency-stability coordinated optimization schemes. Finally, the existing challenges are analyzed, hoping to offer theoretical references for developing high-efficiency and long-lifespan perovskite photovoltaic devices.