Novel Bilayer Strategy Developing Dual-Functional Spray-Pyrolyzed NiO _x toward High-Performance Perovskite Solar Cells

High-quality film formation and efficient charge carrier transport are crucial for high-performance and stable perovskite solar cells (PSCs). However, inefficient charge extraction between the conductive glass and the charge transport layer still remains a severe limiting factor for the device performance and operational stability because of energy level mismatches and interfacial defects. In this work, we propose an innovative strategy for this issue by establishing a bilayer-structured charge transport layer based on spray pyrolysis and ion doping that can simultaneously achieve better substrate morphology and energy level alignment. The inverted PSC incorporating Mg-doped SP-NiO_x demonstrates a champion power conversion efficiency of 22.19%, while maintaining 93.3% of its initial efficiency after 1000 h under the ISOS-D-1 testing protocol. In general, this study has indicated a straightforward and effective interfacial engineering strategy for developing applicable high-performance PSCs.