Highly efficient inverted perovskite solar cells based on amphiphilic self-assembled molecules of...

Developing chemically modified hole-transporting self-assembled monolayers (SAMs) is pivotal for high-performance inverted perovskite solar cells (PSCs). However, simultaneously achieving substrate coverage, interfacial stability, and energy level alignment remains challenging. Herein, guided by the "like dissolves like" principle and the amphiphilic nature of perovskite precursors, we report a fluorinated amphiphilic SAM material, (2-(4-(bis(3-fluoro-4-methoxyphenyl)amino)phenyl)-1-cyanovinyl) phosphonic acid (MPA-CPA-F). The molecule integrates a hydrophobic, electron-donating fluorine/methoxy-substituted triphenylamine core and a hydrophilic cyanophosphonic acid anchor via a rigid π-conjugated vinyl bridge. This fluorinated amphiphilic design facilitates high-quality perovskite deposition by ensuring robust substrate anchoring and superwetting behavior toward perovskite precursors. Notably, MPA-CPA-F coordinates with uncoordinated Pb²⁺ and forms hydrogen bonds with organic cations, effectively passivating interfacial defects, while its large dipole moment optimizes energy level alignment. These synergistic effects significantly suppress non-radiative recombination and accelerate hole extraction, yielding a champion power conversion efficiency (PCE) of 25.88% alongside excellent humidity and thermal stability. This work presents a multifunctional design strategy to overcome the inherent limitations in conventional SAMs.