Homogeneous crystallization via sustained solvent-extraction channels for methylammonium-free all-perovskite tandem solar cells.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41491920.
- Also identified by DOI 10.1038/s41467-025-68213-2 and PMC identifier 12886971.
- Licence recorded as CC BY-NC-ND.
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Abstract
Replacing volatile methylammonium (MA<sup>+</sup>) with formamidinium (FA<sup>+</sup>) or cesium (Cs<sup>+</sup>) 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.