Impact of Nickel Oxide/Perovskite Interfacial Contact on the Crystallization and Photovoltaic Performance of Perovskite Solar Cells

Spray‐coated nickel oxide (NiO X ) is a desirable hole‐transporting material for perovskite solar cells (PSCs) because they are low cost, stable, and readily scalable. Recent research shows that the inferior interface contact of NiO X |perovskite is the main factor that limits the efficiency and stability of the device. Herein, a facile route is introduced to enhance this contact by inserting a tetradecylamine (TeDA) interfacial layer. It is found that TeDA not only can modulate the wettability of NiO X film, thus changing the transformation process of wet film to perovskite, but also can facilitate an efficient charge extraction at this interface. As a result, the efficiency of small‐area (0.16 cm 2 ) solar cells is improved from 15.8% to 18.7%. Moreover, a champion efficiency of 12.9% is achieved for the larger area (53.64 cm 2 ) perovskite solar modules based on spray‐coated NiO X . The optimized devices also show improved stability in comparison with the devices without modification. This work provides a comprehensive understanding of the NiOx|perovskite interface and a new strategy for improving the perovskite quality and photovoltaic performance of PSCs.