Reduced Lattice Mismatch at the Interface of Perovskite and LaNiO₃ Hole Transport Layers for Highly Efficient p–i–n Perovskite Solar Cells

The low hysteresis, good long-term stability, and competitive power conversion efficiency make inverted p–i–n perovskite solar cells (PSCs) a promising architecture for future industrial applications. An essential aspect of achieving high-performance inverted PSCs is the selection and optimization of hole transport layers (HTLs), which are responsible for hole extraction and growth of perovskite films. In this investigation, we utilized a facile hydrothermal method to synthesize LaNiO3 nanocrystals. The resulting LaNiO3 nanocrystal dispersion was employed to fabricate LaNiO3 films as HTLs for the MAPbI3 PSCs. One noteworthy advantage of this approach is the reduced lattice mismatch between LaNiO3 and MAPbI3, which enhances the quality of the LaNiO3/MAPbI3 interface and minimizes microstrain within MAPbI3. Consequently, MAPbI3 PSCs with LaNiO3 HTLs achieved a remarkable champion efficiency of 19.14%, a low hysteresis index of 0.2%, and an improved stability in air. This study demonstrates that the LaNiO3 layer is a promising HTL for inverted PSCs.