High-efficiency perovskite solar cells enabled by suppressing intermolecular aggregation in hole-selective contacts

Hole-selective contacts are crucial for improving the performance of perovskite solar cells, but their optimization still faces obstacles. For example, it is challenging to achieve uniform deposition and prevent aggregation of small-molecule materials during solution processing, negatively impacting cell efficiency, reproducibility and stability. Here we co-deposit a new p-type small molecule (D4PA) with the perovskite film. The intramolecular C–C coupling in D4PA enables strong multi-anchoring interactions with both the perovskite and substrate, enhancing interfacial charge transport and inhibiting defect formation within the perovskite layer. The C–C coupling also introduces steric hindrance, creating twisted molecular conformations that effectively prevent molecular aggregation, extend the solution processability and increase device reproducibility. Our devices exhibit a certified power conversion efficiency of 26.72% and a certified maximum power point tracking efficiency of 26.14% in small-area devices. A power conversion efficiency of 23.37% and a certified maximum power point tracking efficiency of 22.66% are achieved in a mini-module with an effective area of 10.86 cm². The devices maintain over 97.2% of their initial efficiency after 2,500 h of continuous operation at their maximum power point.