Bilateral Chemical Linking at NiO_x Buried Interface Enables Efficient and Stable Inverted Perovskite Solar Cells and Modules

Inverted NiO_x-based perovskite solar cells (PSCs) exhibit considerable potential because of their low-temperature processing and outstanding excellent stability, while is challenged by the carriers transfer at buried interface owing to the inherent low carrier mobility and abundant surface defects that directly deteriorates the overall device fill factor. Present work demonstrates a chemical linker with the capability of simultaneously grasping NiO_x and perovskite crystals by forming a Ni−S−Pb bridge at buried interface to significantly boost the carriers transfer, based on a rationally selected molecule of 1,3-dimethyl-benzoimidazol-2-thione (NCS). The constructed buried interface not only reduces the pinholes and needle-like residual PbI₂ at the buried interface, but also deepens the work function and valence band maximum positions of NiO_x, resulting in a smaller VBM offset between NiO_x and perovskite film. Consequently, the modulated PSCs achieved a high fill factor up to 86.24 %, which is as far as we know the highest value in records of NiO_x-based inverted PSCs. The NCS custom-tailored PSCs and minimodules (active area of 18 cm²) exhibited a champion efficiency of 25.05 % and 21.16 %, respectively. The unencapsulated devices remains over 90 % of their initial efficiency at maximum power point under continuous illumination for 1700 hours.