Reductive 2D Capping Layers through Dopamine Salt Incorporation for Pb–Sn Mixed Perovskite Solar Cells

作者：Rui Meng, Can Li, Jishan Shi, Zhi Wan, Zhihao Li, Zhihao Li, Chongyang Zhi, Yicong Zhang, Zhen Li, Zhen Li · 发表于：ACS Energy Letters · 年份：2023 · DOI：10.1021/acsenergylett.3c02039 · 被引用次数：27 · 研究领域：Perovskite Materials and Applications、Conducting polymers and applications、Organic Electronics and Photovoltaics

Pb–Sn mixed perovskite is a crucial component in all-perovskite tandem cells. However, it remains a challenging task to fabricate Pb–Sn perovskite solar cells (PSCs) due to the facile oxidation of Sn 2+ . In this work, we incorporate dopamine cation (DAH + ) to create a reductive 2D capping layer on a Pb–Sn perovskite film, simultaneously enhancing the efficiency and stability of Pb–Sn PSCs. Dopamine acts as a strong reducing agent that effectively reduces Sn 4+ to Sn 2+ . The 2D/3D heterojunction induces downward band bending at the perovskite top surface, facilitating carrier separation and extraction. Consequently, the champion PSC achieved a power conversion efficiency (PCE) of 22.31%. Benefiting from the protection of the reductive 2D capping layer, the device’s stability is notably enhanced with 86% of the initial PCE retaining after 1000 h operation in N 2 . This work demonstrates a promising strategy of constructing a multifunctional 2D passivation layer toward high quality Pb–Sn mixed perovskite devices.