Fluorinated Black Phosphorene Nanosheets with Robust Ambient Stability for Efficient and Stable Perovskite Solar Cells

• Published in: Advanced functional materials 2022-01, Vol.32 (1), p.n/a
• Main Authors: Liu, Tao, Liu, Yinjiang, Chen, Mengwei, Guo, Xi, Tang, Shuai, Zhang, Ruoqian, Xie, Zuji, Wang, Jie, Gu, Anping, Lin, Shiwei, Wang, Ning
• Format: Article
• Language: English
• Subjects: Adatoms; ambient stability; Carrier mobility; electrochemical delamination; Energy conversion efficiency; Energy gap; fluorinated black phosphorus; Fluorination; Fluorine; hole extraction; Hydrogen bonds; Materials science; Metal halides; Nanosheets; Optoelectronics; perovskite solar cells; Perovskites; Phosphorene; Photovoltaic cells; Quantum dots; Solar cells; Stability
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202106779

Extraordinary electronic and photonic features (e.g., tunable direct bandgap, high ambipolar carrier mobility) render few‐layer black phosphorus (BP) nanosheets/quantum dots an important optoelectronic material. However, most of the BP applied in metal halide perovskite solar cells (PSCs) are produced by sonication‐assisted liquid exfoliation, which inevitably brings inferior electronic properties, thus leading to limited beneficial effects. Furthermore, this study uncovers that the intrinsic instability of BP nanosheets sandwiched between (CsFAMA)Pb(BrI)3 perovskite and spiro‐OMeTAD has a deleterious effect on the performance stabilization of PSCs. To address the above constraints, a feasible strategy herein is developed by introducing high‐quality fluorinated BP (F‐BP) nanosheets synthesized by one‐step electrochemical delamination. In addition to P‐Pb coordination, there is a strong hydrogen bond between F− and MA+/FA+ as well as an ionic bond between F− and Pb2+ for the perovskite/F‐BP interface, thus leading to fewer interfacial traps than perovskite/BP, which is responsible for the highest power conversion efficiency (22.06%) of F‐BP devices. More importantly, F‐BP devices exhibit significantly improved humidity and shelf‐life stabilities due to the excellent ambient stability of F‐BP, resulting from the antioxidation and antihydration behavior of fluorine adatoms. Overall, the findings provide a promising strategy to simultaneously enhance the photovoltaic performance and long‐term stability of BP‐based PSCs. In addition to P‐Pb coordination, there is a hydrogen bond between F− and MA+/FA+ as well as an ionic bond between F− and Pb2+ for perovskite/fluorinated black phosphorene (F‐BP), thereby achieving high PCE (22.06%). Significantly, F‐BP devices exhibit improved humidity and shelf‐life stabilities due to the excellent ambient stability of F‐BP nanosheets, resulting from antioxidation and antihydration behavior of fluorine adatoms.