Multisite Anchoring Strategy of Rationally Designed Molecular Passivator for Achieving Efficient and Stable Perovskite Solar Cells.

Abstract

The inherent trap defects in perovskite materials severely limit the performance and stability of perovskite solar cells (PSCs). In this study, we introduce a novel multisite anchoring strategy (MAS) through the rational design of a 7-fluorobenzo[<i>b</i>]thiophene-2-carboxylic acid as a molecular passivator, aimed at simultaneously addressing multiple defects in perovskite films. The molecular passivator incorporates a benzothiophene backbone, a carboxylic acid group, and fluorine atoms, which work in synergy to reduce defect states and enhance the charge carrier extraction efficiency. As a result, the fabricated PSCs based on vacuum flash evaporation could achieve a high efficiency of 26.92% (with a stabilized certified efficiency of 26.79%). Moreover, the PSC devices could maintain over 96.2% of their initial efficiency after 2000 h of aging by the maximum power point tracking. This work paves the way for the design of multifunctional molecular additives that not only improve device efficiency but also ensure long-term operational stability.