Polycarbazole-SAM Hybrid Interface Engineering for Efficient Hole Extraction in Perovskite Photovoltaic Devices

Self-assembled monolayers (SAMs) anchored on nickel oxide substrates have emerged as pivotal hole-selective contacts in p-i-n perovskite solar cells (PSCs), enabling efficient hole extraction while blocking electron transfer. Despite their merits, interfacial issues such as incomplete SAM coverage and molecular aggregation compromise device stability. Herein, we propose a hybrid interfacial architecture that integrates SAMs with the polymer poly(vinylcarbazole) (PVK) to synergistically combine the advantages of both components. The introduced PVK promotes SAM coverage and optimizes the interfacial energy alignment, thereby effectively suppressing nonradiative recombination. Furthermore, the PVK chains penetrate the perovskite matrix, creating an interpenetrating network at the buried interface that further facilitates hole extraction. The resulting PSCs with this hybrid interface achieve a champion efficiency exceeding 23% along with enhanced device stability. This PVK-SAM hybrid strategy addresses the limitations of SAM coverage and reinforces the interfacial contact, offering an alternative design paradigm for high-performance p-i-n PSCs.