Improved Buried Interface Contact in Inverted Perovskite Solar Cells with Dual-Site-Binding Molecules

Abstract

The buried interface in inverted perovskite solar cells (PSCs) is critical for device performance, yet it is prone to defect formation and non-ideal energy alignment. In this work, we introduced ethyl (methylthio)acetate (EMA), a simple yet novel molecule featuring dual-site groups (carbonyl and methylthio), as a modifier for the buried perovskite interface to simultaneously passivate interfacial defects and regulate perovskite crystallization. EMA facilitates strong interactions with undercoordinated Pb²⁺ ions via its carbonyl and methylthio groups, thereby reducing trap states and enhancing charge carrier dynamics. The modified interface promotes the crystallinity of perovskite grains, improves energy level alignment, and suppresses non-radiative recombination. As a result, the EMA-treated device achieves a champion power conversion efficiency of 25.07% with improved open-circuit voltage and fill factor, and obtains a stabilized power conversion efficiency of 25.00%. Moreover, the devices exhibit enhanced thermal and long-term stability, retaining over 94% of their initial efficiency after 2400 h of aging. This work provides a simple and effective strategy for buried interface engineering toward efficient and stable inverted PSCs.