Navigating Molecular Structures of Self-Assembled Monolayers for High Efficiency Perovskite Photovoltaics

Self-assembled monolayers (SAMs) have become the cornerstone of modern inverted perovskite solar cells, driving power conversion efficiency up to 27.3% and perovskite/silicon tandem devices up to 34.85%. This revolution stems from molecular engineering governing interfacial charge extraction and defect passivation. This review decodes the structure-function relationships of SAMs, moving beyond conventional applications to explore anchoring groups, conjugated linkers, and Lewis basic terminal groups. We highlight how the molecular engineering of SAMs mitigates energy-level offsets and suppresses nonradiative recombination via hard-soft acid-base interactions. Special emphasis is placed on emerging co-SAM strategies and in situ cross-linking techniques that overcome single-component limitations by creating synergistic interlayers. In the end, we outline a roadmap for rational SAM design bridging molecular insights with industrial scalability.