Mitigating residual MA<sup>+</sup> for stable FAPbI<sub>3</sub> perovskite photovoltaics.

Zhao, Ke; Yao, Libing; Değer, Caner; Zhang, Xu; Shen, Jiahui; Miao, Xiaohe; Shi, Pengju; Luo, Yixin et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Perovskite solar cells (PSCs) based on formamidinium lead iodide (FAPbI₃) demonstrate near-ideal bandgaps approaching the Shockley-Queisser efficiency limit, yet residual MA⁺ from methylammonium chloride (MACl) additives compromises their operational stability under thermal/light stress. Therefore, we developed an α-phase-assisted antisolvent method employing MACl-free precursors to fabricate α-FAPbI<sub>3</sub> films. These films exhibit enhanced thermal stability and structural integrity, which were comprehensively characterized using multiple techniques. The optimized devices achieved a 26.1% power conversion efficiency (PCE), ranking among one of the highest reported values for FAPbI<sub>3</sub>-based inverted PSCs, and exhibit sustained stability under accelerated aging conditions. This strategy resolves the MA⁺-induced degradation bottleneck, paving the way for commercially viable high-performance PSCs.