Researchers from Sichuan University, Zhejiang University, the Chinese Academy of Sciences, and Guangxi University have reported a nucleation layer-assisted (NLA) strategy that enables highly oxygen-stable quasi-2D Ruddlesden-Popper (RP) tin perovskite solar cells by modulating phase distribution, crystal orientation, and film morphology. The breakthrough sets a new benchmark for oxygen stability in tin perovskite solar cells.
The NLA process involves rinsing a prepared perovskite film and annealing the residue onto a substrate, creating a new template for perovskite film fabrication. This nucleation layer transforms the subsequently deposited perovskite film from a broad phase distribution dominated by small-n values with random crystal orientations into a narrow phase distribution dominated by medium-n values with vertical crystal orientations.
The nucleation layer also improves perovskite film morphology, yielding highly co-oriented plate-like grains that reduce grain boundaries and pinholes. The resulting NLA perovskite film exhibits enhanced carrier transport efficiency, lower exciton binding energy, weakened electron-phonon coupling, and a significantly reduced oxygen diffusion rate under exposure.
Consequently, quasi-2D RP tin (Sn)-based perovskite solar cells achieved a champion efficiency of 11.18%. After 2,700 hours of oxygen aging tests, the unencapsulated devices retained 95% of their initial efficiency—a record oxygen stability for tin-based perovskite solar cells, according to the team.
