メチルアンモニウムフリー all-ペロブスカイトタンデム太陽電池のための持続的溶媒抽出チャネルを介した均一結晶化

Replacing volatile methylammonium (MA⁺) with formamidinium (FA⁺) or cesium (Cs⁺) cations in mixed Pb-Sn perovskite compositions improves thermal resilience. Nevertheless, the low-solubility Cs-based perovskite tends to preferentially crystallize into a dense Cs-rich surface layer during the AS-assisted crystallization process, which impedes the AS to extract the internal solvent. Here, we introduce a multi-Lewis-base modulator to maintain sustained solvent-extraction channels (SSC) open throughout the AS process, thereby homogenizing MA-free mixed Pb-Sn perovskite crystallization in depth. This approach yielded a PCE of 22.7% in FACs Pb-Sn perovskite solar cells. We fabricated monolithic all-perovskite tandem solar cell with a high PCE of 29.2% (certified PCE of 29.2%), which is the highest certified PCE for MA-free all-perovskite TSCs. The unencapsulated FACs-based mixed Pb-Sn perovskite solar cell remained over 80% of its initial PCE after 800 h of aging at 85 °C. This strategy enables the simultaneous realization of high-performance and thermal stability.