Indene-C60 Bisadduct Electron-Transporting Material with the High LUMO Level Enhances Open-Circuit Voltage and Efficiency of Tin-Based Perovskite Solar Cells

Tin-based halide perovskite materials are promising ecofriendly light absorbers with similar optoelectronic properties to lead-based ones. However, their solar cells have suffered from considerably low open-circuit voltage ( V OC ) arising from mismatched energy levels between tin-based perovskite and charge-transporting layers because they imitate typical device structures developed for lead-based ones. Herein, we report that the lowest unoccupied molecular orbital (LUMO) level of the electron-transporting layer (ETL) significantly affects V OC of tin-based perovskite solar cells (PSCs) in contrast to lead-based ones. The indene-C 60 bisadduct ETL with a much higher LUMO level than that of typical ETLs decreases an energy off-set with the conduction band minimum of the mixed formamidinium/phenylethylammonium tin iodide (FA 0.9 PEA 0.1 SnI 3 )-based perovskite material. The resultant red…