Temperature-controlled anti-solvent engineering enables the fabrication of reproducible and stable tin-based perovskite solar cells by decoupling the kinetic fragility

Abstract

Tin-based perovskites are among the most promising lead-free, solution-processed photovoltaic absorbers. However, their practical deployment is limited by uncontrolled crystallization kinetics, a narrow process window and severe energetic disorder resulting from rapid nucleation. Here, we demonstrate that modulation of anti-solvent temperature (cool to hot anti-solvent treatment) leads to a significant impact on crystallinity, grain packing and electronic features of the films. This transformation allows for governing the crystallization process with temperature and makes it fabrication-tolerant. We also examine the pre-annealing passivation of precursor films (passivation before post-thermal annealing). This dual control suppresses energetic disorder and non-radiative recombination without altering the optical bandgap or absorbance. This improvement increases the power conversion efficiency from 3.50% to 9.12%. In situ optical spectroscopy reveals a dramatic change in perovskite formation during the post-annealing process. Our synergistic control of thermal processes enhances efficiency, operational stability and reproducibility, paving the way to overcome defects in tin-halide perovskite photovoltaics.