Synergistic Molecular Engineering of Novel Self‐Assembled Monolayer for Perovskite Solar Cells

The commonly used self‐assembled hole transport monolayer (SAM) in perovskite solar cells always suffer aggregation, energy level mismatch, and weak interaction with perovskite. Design and develop of novel SAM have been proven to be an important approach to enhance device efficiency and stability. Herein, a novel SAM incorporates methoxynaphthalene as terminal group was successfully developed, named MeONa‐4PACz. Compared with commercial MeO‐4PACz, MeONa‐4PACz exhibits more uniform distribution on the substrate due to the distorted molecular configuration. The MeONa‐4PACz‐based substrates display improved wettability for perovskite precursor, leading to enhanced perovskite crystallization. The introduction of naphthalene decreases the size of the π‐conjugated system and lowers HOMO level, which achieves better alignment with the valence band of the perovskite layer. Moreover, the superior interaction between MeONa‐4PACz with perovskite effectively suppress non‐radiative recombination. Consequently, the device employing MeONa‐4PACz achieved a high power conversion efficiency of 26.07%. Additionally, devices based on MeONa‐4PACz demonstrate exceptional stability compared to MeO‐4PACz.