Carbazole-based self-assembled monolayers (SAMs) were widely adopted as hole-selective layers (HSLs) and recombination junction material in perovskite/silicon tandem solar cells (P/S-TSCs), yet it remains challenging to simultaneously suppress excessive molecular aggregation and maintain continuous charge-transport pathways, particularly on textured silicon substrates. Herein, we report series of sterically extended asymmetric carbazole-based SAMs, 4-(11H-benzoacarbazol-11-yl)benzoic acid (BABCz), 4-(9H-dibenzoa,ccarbazol-9-yl)benzoic acid (BADBCz), and 4-(3’,6’-dimethoxy-9H-3,9’-bicarbazol−9-yl)benzoic acid (MeO-BADCz), in which MeO-BADCz engineers to construct a continuous three-dimensional C–H···π-mediated charge-transport network while effectively restraining long-range crystallization. The MeO-BADCz monolayer combines strong anchoring to substrate, pronounced work-function modulation, and efficient defect passivation at the buried interface, enabling pinhole-free, highly crystalline wide-bandgap (1.68 eV) perovskite films with suppressed non-radiative recombination. Through these advancements, the optimized wide-bandgap perovskite solar cells (PSCs) incorporating MeO-BADCz as the HSL deliver a power conversion efficiency (PCE) of 24.05% with negligible hysteresis and retain 97.1% of their initial efficiency after 1000 h of continuous operation under ISOS-L-1 protocol. When implemented as the recombination layer on textured silicon heterojunction (SHJ), MeO-BADCz further enables P/S-TSCs with a certified PCE of 33.04% and robust stability under damp-heat-light conditions. This work demonstrates a steric-engineering concept for asymmetric carbazole-based SAMs and highlights texture-tolerant multidimensional charge-transport networks as a key motif for scalable tandem photovoltaics. Carbazole-based monolayers aid perovskite–silicon tandem solar cells yet preventing aggregation while maintaining charge transport on textured silicon is challenging. Yan et al. create sterically extended asymmetric carbazole molecules that form continuous three-dimensional pathways, improving efficiency and stability.
Yan et al. (Fri,) studied this question.