Efficient Environment?friendly Lead?free Tin Perovskite Solar Cells Enabled by Incorporating <scp>4?Fluorobenzylammonium</scp> Iodide Additives

Development of tin (Sn)-based perovskite solar cells (PSCs) largely lags behind that lead counterparts due to fast crystallization process Sn and numerous defects in both bulk surface films. Herein, this work reports a facile strategy introducing 4-fluorobenzylammonium iodide (FBZAI) as additives into precursor synergistically modulate the roles benzylamine fluorine Sn-based PSCs. Incorporation FBZAI can increase crystallinity, passivate defects, inhibit oxidation Sn2+, leading suppression nonradiative recombination enhancement charge transport collection devices. As result, best-performing PSC with additive achieves maximum PCE 13.85% enhanced fill factor 77.8% open-circuit voltage 0.778 V. Our unencapsulated device exhibits good stability by maintaining 95% its initial after 160 days storage.