Surface chemistry-induced reconstruction of inorganic perovskites for efficient and stable inverted solar cells

Abstract

Metal halide inorganic perovskites, known for their excellent thermal stability and ideal bandgaps, have shown tremendous potential for high-performance tandem solar cells. However, the performance of inorganic perovskite solar cells with inverted structures remains far from practical usage due to undesirable interfaces. Herein, we report that the introduction of benzyl chloromethyl sulfide can in situ induce surface chemical reactions, forming a new phase on the inorganic perovskite surface and incorporating chloride to coordinate with surface lead. These dual functions fundamentally optimize the interfacial charge transfer, resulting in a considerable increase in device power conversion efficiency (PCE) from 18.50% to 20.82% (certified 20.20%). More importantly, the treated solar cell demonstrates outstanding operational stability by tracking at maximum power point under continuous 1-sun illumination, preserving 90% of its PCE for over 3,000 h. By contrast, the reference devices drop to 48% in 1,500 h.