Self-Assembled Monolayer Suppresses Interfacial Reaction between NiO<sub><i>x</i></sub> and Perovskite for Efficient and Stable Inverted Inorganic Perovskite Solar Cells
Zuxiong Xu, Jianwei Wang, Zhongyu Liu, Cong Xiao, Jiahao Wang, Ning Liu, Jing Zhang, Like Huang, Ziyang Hu, Yuejin Zhu, Xiaohui Liu
Abstract
Inorganic NiO x has attracted tremendous attention in organic–inorganic hybrid perovskite solar cells (PSCs) in recent years but is relatively less used in all-inorganic PSCs. In this study, we have discovered and confirmed the detrimental interfacial reaction between NiO x and DMAI-containing CsPbI 3 inorganic perovskites. Thus, a self-assembled monolayer, Br-2PACz, is employed to modify the NiO x surface to obstruct the adverse interfacial reaction and further improve the device performance. The results demonstrate that Br-2PACz modification on NiO x can also improve interface contact, perovskite film morphology, and energy level alignments. Consequently, a champion power conversion efficiency (PCE) of 19.34% with a high open-circuit voltage ( V OC ) of 1.15 V is obtained for inverted NiO x /Br-2PACz-based CsPbI 3 PSCs compared to the reference NiO x -based PSC with a moderate PCE of 15.16% ( V OC 1.05 V). Moreover, the stabilities of both CsPbI 3 films and devices exhibited significant enhancement after Br-2PACz modification. The unpacked PSCs could maintain 80, 73, and 89% of the initial efficiency after aging in 30–35% RH for 960 h, heating at 60 °C for 48 h, and continuous illumination for 284 h, respectively, highly superior to the reference devices. Our work offers a facile and effective approach for developing high-performance inverted NiO x -based CsPbI 3 PSCs.