Mitigating Sn2+ Oxidation and Enhancing Device Performance in Tin-Based Perovskites Solar Cell via CsTFA Additive Strategy

Tin-based perovskite solar cells (TPSCs) have been recognized as a viable lead-free alternative in the field of solar energy technology; however, their development is significantly limited by the oxidation of Sn²⁺ to Sn⁴⁺, which introduces deep-level defects and accelerates non-radiative recombination. In this study, cesium trifluoroacetate (CsTFA) is employed as an antioxidant additive to address these challenges. CsTFA not only effectively suppresses Sn²⁺ oxidation but also passivates intrinsic defect and alleviates the p-type self-doping effect. Consequently, CsTFA-doped devices exhibit significant enhancements in open-circuit voltage (VOC) and fill factor (FF), leading to a 14% enhancement in power conversion efficiency (PCE), along with significantly improved storage stability. This work provides a facile and efficient approach to mitigate Sn2+ oxidation and suppress non-radiative losses, offering a viable pathway toward high-performance, stable tin-based perovskite optoelectronic devices.