Anchor Engineering of Hole‐Selective Enamine‐Based Self‐Assembling Monolayers for Perovskite Solar Cells

ABSTRACT The transition to renewable energy sources, particularly solar power, has highlighted the potential of next‐generation perovskite solar cells (PSCs), which have achieved a power conversion efficiency (PCE) over 27%, rivaling conventional silicon solar cells. A critical component in p‐i‐n PSCs is hole transporting layer (HTL), where polymers like PTAA have shown promise but face challenges in efficiency and commercial viability hindered by high costs and complex synthesis. Recently, enamine‐based HTMs have emerged as a promising alternative due to their superior charge transport properties, structure's tunability, and cost‐effectiveness. Additionally, self‐assembling monolayers (SAMs) have been explored to improve inverted PSC performance by enhancing interface properties and reducing material use. This study combines enamine chemistry and self‐assembly to engineer enamine‐based SAMs with various structural units having ─COOH and ─PO(OH) 2 anchoring groups to optimize SAM/TCO interface and reduce recombination losses. The resulting p‐i‐n devices exhibit high power conversion efficiencies (>25.5%) and improved stability. The champion mini‐module with an aperture area of 29.7 cm 2 realizes a PCE of 23.14% with an FF of 83.11%, highlighting the potential of these materials for scalable photovoltaic applications.