Cooperative Dual‐Directional π – π Stacking in Self‐Assembled Monolayers for High‐Performance Inverted Perovskite Solar Cells

Abstract

ABSTRACT The evolution from monomeric to dimeric self‐assembled monolayers (SAMs) opens new opportunities for inverted perovskite solar cells (PSCs), yet stronger π – π interactions in these larger architectures risk inducing aggregation over ordered assembly, making it challenging to maintain a well‐balanced intermolecular packing. We design a symmetric indenocarbazole dimer (DIC) to harness cooperative face‐to‐face and edge‐to‐edge π – π stacking for directing intermolecular attraction into ordered, long‐range assembly rather than uncontrolled aggregation. In stark contrast, its asymmetric indenocarbazole‐carbazole conjugate (ICCB) suffers from random clustering and incomplete passivation. This ordered SAM template provides a homogeneous foundation for perovskite crystallization, delivering a champion PCE of 26.33% with an outstanding FF of 86.62%, significantly outperforming ICCB (24.80%), while retaining over 85% of its initial efficiency after 1600 h. Our findings establish molecular symmetry and dual‐directional π – π interactions as critical design principles for high‐performance dimeric SAMs.