Overcome Low Intrinsic Conductivity of NiO<sub><i>x</i></sub> Through Triazinyl Modification for Highly Efficient and Stable Inverted Perovskite Solar Cells
Jiabao Yang, Tong Wang, Yaohua Li, Xingyu Pu, Hui Chen, Yuke Li, Bowen Yang, Yixin Zhang, Junsong Zhao, Qi Cao, Xingyuan Chen, Shahnaz Ghasemi, Anders Hagfeldt, Xuanhua Li
Abstract
Nickel oxide (NiO x ) is a promising hole transport material in inverted organic‐inorganic metal halide perovskite solar cells. However, its low intrinsic conductivity hinders its further improvement in device performance. Here, we employ a trimercapto‐s‐triazine trisodium salt (TTTS) as a chelating agent of Ni 2+ in the NiO x layer to improve its conductivity. Due to the electron‐deficient triazine ring, the TTTS complexes with Ni 2+ in NiO x via a strong Ni 2+ ‐N coordination bond and increases the ratio of Ni 3+ :Ni 2+ . The increased Ni 3+ concentration adjusts the band structure of NiO x , thus enhancing hole density and mobility, eventually improving the intrinsic conductivity of NiO x . As a result, the device with TTTS modification displays a champion power conversion efficiency (PCE) of 22.81%. The encapsulated device based on a modified‐NiO x layer maintains 94% of its initial power output at the maximum power point and continuous one‐sun illumination for 1000 h at 45 °C. In addition, the unencapsulated target devices also maintain 92% at 60 ± 5% relative humidity and 25 °C in the air for 5000 h; and 91% at 85 °C in a nitrogen atmosphere for 1000 h. The research provides an effective strategy to enhance PCE and stability of inverted PSCs via modifying NiO x films with triazine molecule.