Abstract
nip-type lead-based perovskite solar cells (LPSCs) swept nearly all record power conversion efficiencies (PCEs) since the advent of perovskite-based photovoltaic technology. In contrast, nip-type tin-based perovskite solar cells (TPSCs) are not satisfied and lag far behind their pin-type counterparts. A key contributing factor is the indiscriminate adoption of metal oxide electron transport layers (ETLs) from nip-type LPSCs to nip-type TPSCs. Here, we reveal the origin and underlying mechanism of metal oxide ETLs on the poor performance of the nip-type TPSC and propose a novel metal chalcogenide ETL, specifically Sn(S0.92Se0.08)2, to replace them. This newly developed metal chalcogenide ETL not only circumvents the oxygen molecules desorption and impedes the Sn2+ oxidation, but also exhibits a tailored band structure, improved morphology, heightened conductivity, and increased electron mobility. As a result, TPSCs with Sn(S0.92Se0.08)2 ETLs demonstrate significant increase in open-circuit voltage, rising from 0.48 to 0.73V, and a noteworthy enhancement in PCE, soaring from 6.98 to 11.78%, representing a more than 65% improvement. Additionally, TPSCs with Sn(S0.92Se0.08)2 ETLs exhibit improved operational stability, retaining over 95% of their initial efficiency after 1632 h. Our findings underscore a substantial advancement in nip-type TPSC performance and stability, showcasing metal chalcogenides as promising candidates for future nip-type TPSC applications.