Synergistic Density Enhancement and Energetic Alignment via Tailored Postassembly of Self-Assembled Molecules for Perovskite Solar Cells

Achieving a fully coalesced and energetically optimized buried interface remains a bottleneck for inverted perovskite solar cells (PSCs), as single-step self-assembled molecules (SAMs) often exhibit microscopic vacancies due to stochastic anchoring. In this work, we report a structural analogue strategy using a tailored derivative, MeO-ADCP, for the post-treatment of high-performance RS-2 SAM. By substituting the phenoxazine core with a dimethyl-substituted acridine moiety, MeO-ADCP achieves superior solubility through controlled steric hindrance, enabling it to effectively populate the remaining interstices within the RS-2 matrix. This coassembly notably increases the assembling density and modifies the interfacial energy levels, facilitating a more seamless energetic transition for hole extraction. Consequently, the optimized devices demonstrate a marked reduction in nonradiative recombination, achieving a power conversion efficiency of 26.8% and maintaining over 99% of their initial efficiency after 2000 h of continuous operating at 45 °C.