Boosting Efficiency and Stability of NiOx‐Based Inverted Perovskite Solar Cells Through D–A Type Semiconductor Interface Modulation

Abstract NiO x is one of the promising inorganic hole transporting materials in inverted perovskite solar cells (PSCs), however, its device efficiency and stability are still limited by the energy level mismatch, low intrinsic conductivity, high interface defect density, and complex active species. Herein, the use of an imide‐based donor–acceptor type semiconductor (BTF14) as the interlayer between perovskite and NiO x is proposed, which facilitates the hole extraction and transfer, reduces the defect density at interface and in perovskite film bulk, and further reduces the concentration of Ni >3+ species to stabilize the heterointerface. As a result, the power conversion efficiency of inverted PSCs can be significantly boosted from 22.11% of NiO x to 24.20% of NiO x /BTF14. Moreover, NiO x /BTF14 based devices also exhibit negligible hysteresis and excellent long‐term stability, with over 77% of their initial efficiency remaining after continuous operation at 60 °C for 1000 h under 1 sun illumination.