Hole-Selective Monolayer Molecules with Spatially Separated Carrier Orbitals and Twisted π-Skeleton for Inverted...

The development of monolayer hole-selective contacts has proven to be an effective strategy for enhancing the performance and scalability of inverted perovskite solar cells (PSCs). However, current monolayer molecules often suffer from limited charge separation and extraction capabilities due to their small π-conjugated domains, localized carrier orbitals, and weak interfacial binding with substrates. Here, we report a molecular design featuring a double donor-acceptor (D-A) conjugated architecture with an enhanced push-pull effect, spatially separated carrier orbitals for efficient hole extraction and electron blocking, bifacial anchoring for strong binding to both metal oxide substrates and perovskite layers, and a twisted π-skeleton that suppresses self-aggregation and ensures homogeneous monolayer distribution. By replacing conventional [2-(9H-carbazol-9yl)ethyl]phosphonic acid (2PACz) with this double D-A-type monolayer, the PCE improves from 23.69% to 25.61% (certified 25.11%) in small-area PSCs, while large-area perovskite modules (active area of 10.04 cm²) achieve a high PCE of 21.40%. Notably, the devices exhibit excellent operational stability under continuous illumination (100 mW cm^-2) at an elevated temperature (85 °C), maintaining 84.9% of the initial efficiency after 1000 h.