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 LaNiO 3 nanocrystals. The resulting LaNiO 3 nanocrystal dispersion was employed to fabricate LaNiO 3 films as HTLs for the MAPbI 3 PSCs. One noteworthy advantage of this approach is the reduced lattice mismatch between LaNiO 3 and MAPbI 3, which enhances the quality of the LaNiO 3 /MAPbI 3 interface and minimizes microstrain within MAPbI 3 . Consequently, MAPbI 3 PSCs with LaNiO 3 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 LaNiO 3 layer is a promising HTL for inverted PSCs.