LAUSR

Nickle oxide (NiO) with excellent stability and favorable energy band are desirable candidate for hole selective contact (HSC) of inverted perovskite solar cell (PSC). However, current works focused on addressing interfacial issues, which would be induced by the poor NiO/perovskite contact or other defects, are scarce. Herein, a facile one-step hydrothermal strategy is demonstrated to develop 3D NiO nanowall (NW) film as promising HSC. Such newly-designed NiO NWs HSC exhibits robust, homogenous mesoporous network structure, which would improve NiO/perovskite interface contact, passivate the interfacial defect and promote the quality of perovskite film. Hence, the optimized interface features enable the power conversion efficiency (PCEs) approaching ~18%. Moreover, the additional diethanolamine (DEA) interlayer was introduced to further passivate the intrinsic defect of NiO surface, thereby fabricating the better charge transfer with suppressed recombination loss. As a result, the champion PCE of NiO NWs/DEA based device was boosted up to 19.16% with high open-circuit voltage (~1.11 V) and fill factor (> 80%), which is prominent in MAPbI 3 -based inverted PSCs. Besides, the device exhibits the better stability and lower hysteresis behavior compared with conventional solution-based NiO nanocrystal device.