Boosting All‐Perovskite Tandem Solar Cells by Revitalizing the Buried Tin‐Lead Perovskite Interface

Narrow-bandgap (NBG) mixed tin-lead (Sn-Pb) perovskite solar cells (PSCs) serve as crucial top subcells in all-perovskite tandem solar cells (TSCs). However, the prevalent use of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) hole transport layers (HTLs) in NBG PSCs compromises device efficiency and stability. To address this, the study proposes a revitalizing strategy for the buried interface of Sn-Pb perovskites by directly immersing acetylcholine chloride (ACh) into PEDOT: PSS. ACh acts as a proficient "diver," not only modulating the bottom PEDOT: PSS HTLs but also facilitating the reconstruction of the buried interface and significantly enhancing the quality of the top perovskite layers. This intervention with ACh prevents Sn