Molecule‐Assisted Dispersion of Self‐Assembled Monolayers for High‐Efficiency and Stable Perovskite Solar Cells

ABSTRACT Self‐assembled monolayers (SAMs) are widely used in inverted perovskite solar cells (PSCs) due to their high hole mobility, excellent interfacial modification capability, and low‐cost fabrication processes. However, conventional SAMs suffer from molecular aggregation during film formation, leading to non‐uniform and low coverage issues, which ultimately hinder the enhancement of PSCs performance. Herein, this work presents a strategy to tackle this challenge through the modification of [4‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl)butyl]phosphonic acid (Me‐4PACz) with O‐Phospho‐L‐tyrosine (OPLt) molecules. The aggregation of Me‐4PACz molecules is suppressed through disrupting Me‐4PACz dimers and reducing the intermolecular π‐π stacking, while the anchoring sites for the SAM layer on the NiO x substrate are optimized, facilitating enhanced interfacial contact and consequent perovskite crystallization. Eventually, PSCs based on the Co‐SAM show a performance improvement, with a power conversion efficiency (PCE) of 26.03%. Meanwhile, the device stability has been effectively enhanced, with the efficiency retaining 81.90% of its initial value after 1200 h of continuous one‐sun illumination. This work focused on the coverage and film quality of hole transport layers and demonstrated a molecule‐assisted dispersion strategy toward high‐efficiency and stable PSCs.