Self-assembled monolayers for perovskite solar cells: from molecular architecture to large-area manufacturing

The buried interface in p-i-n perovskite solar cells (PSCs) represents a primary bottleneck to achieve theoretical efficiency limits and long-term operational durability due to severe non-radiative recombination, energy level misalignment, and impeded charge extraction. Self-assembled monolayers (SAMs) have emerged as a transformative interfacial engineering platform. Their nanoscale thickness, customizable molecular structures, and spontaneous chemical anchoring allow for precise work-function tuning, effective defect passivation, and controlled perovskite crystallization. As SAMs continue to set efficiency records in small-area lab devices, adapting these molecular layers for large-area, high-throughput industrial processing has become the vital step toward commercial deployment. Therefore, a thorough review bridging molecular design, interfacial mechanisms, and large-scale manufacturability is urgently required. Herein, we systematically review recent progress in SAM-based contacts for PSCs. We detail the tripartite architecture of anchoring, spacer, and tail groups, unravel mechanisms governing energy alignment and passivation, map the structural evolution from carbazole monomers to polymeric systems, and assess scalable coating protocols for large-area modules. This review provides essential scientific and practical guidelines to bridge laboratory research and industrial-scale manufacturing for perovskite photovoltaics.