An Emerging Stannous Fluoride Complex‐Enabled Highly Efficient Electron Collection and High Stability of Tin‐Based Perovskite Solar Cells

Abstract

In advancing high‐performance tin‐based perovskite solar cells, rapid crystallization and oxidation susceptibility are key challenges. SnF2, often added to control crystallization and oxidation, may impact cell performance, particularly post‐annealing. This study employs in‐situ variable‐temperature X‐ray Diffraction (XRD) to examine SnF2's physicochemical behavior and phase transitions in these cells. Our analysis highlights how residual SnF2 affects carrier recombination through energy‐level structures. Post‐film formation, SnF2 chemically interacts with 2,2':6',2''‐Terpyridine (TPY), forming a stannous fluoride complex that enhances electron transport and energy alignment. Crucially, TPY passivates surface defects and reduces tin vacancies, boosting device stability. Our experimental results indicate that the unencapsulated devices in air atmosphere exhibit a stable power output (SPO) retention rate above 90% of the initial efficiency after 29.5 hours. After ∽800 hours of continuous illumination in ambient air, the conversion efficiency can still be maintained above 100%. Remarkably, the t90 (time to retain 90% efficiency) of the target device in pure oxygen is over 24 hours.This article is protected by copyright. All rights reserved.