Recent Advances in the Self‐Assembled Interlayers for Organic Solar Cells: Materials and Device Engineering

Organic solar cells (OSCs) have made remarkable progress over the past decade, driven by advancements in device architecture, interfacial engineering, and nonfullerene small‐molecule acceptors (NF–SMAs). The power conversion efficiency of OSCs has reached up to 21% due to the strong intramolecular charge‐transfer characteristics of NFSMAs and the work function aligning properties of self‐assembled monolayers (SAMs). Despite these achievements, OSCs still lag in terms of stability and scalability for commercialization. This review highlights the recent progress in SAM‐engineered OSCs, emphasizing their molecular designs, fabrication strategies, and multifunctional roles in work function modification, charge generation, transport, and extraction. Novel SAM design and functionalization approaches have also been addressed. Stability challenges, efficiency–durability tradeoffs, and scalability considerations are also discussed, offering insights into the future prospects of SAM‐integrated OSC technology. Further improvement through interfacial and morphology engineering is crucial for the large‐scale commercialization of OSCs.