Efficient Inverted Perovskite Solar Cells with a Low‐Dimensional Halide/Perovskite Heterostructure

Abstract The photovoltaic performance of inverted (positive‐intrinsic‐negative) perovskite solar cells (PSCs) is predominantly limited by interfacial recombination loss. Here, by constructing a low‐dimensional halide/perovskite heterostructure, non‐radiative recombination pathways at the perovskite/C 60 contact are effectively eliminated and a voltage loss of only 370 mV is achieved in inverted PSCs. Through molecular engineering of the organic spacer, a strong electronic coupling is enabled at the heterointerface, which effectively shifts the gap states out of the bandgap and leads to a prolonged carrier lifetime of 4.28 µs. Our strategy enables a power conversion efficiency of 24.09% (certified 23.54%) for inverted PSCs with an open‐circuit voltage of 1204 mV, and an efficiency of 21.89% (certified 21.48%) for centimeter‐scale cells. The devices retain 92% of the initial efficiency after 85 °C thermal aging for over 1400 h, and 95% of the initial efficiency after 1008 h of maximum power point operation under AM1.5G illumination in air.