Multiple noncovalent conformational locks combined with π-bridge engineering as high-performance Y-series acceptors for organic photovoltaics

Noncovalent conformational lock (NCL) strategies are widely employed to construct high-performance organic semiconductors. The systematic exploration of the influence of NCLs on the acceptors and interfaces from the atomic scale can help to achieve high-performance optoelectronic materials and devices. Here, we present a strategy integrating NCLs and π-bridge to design three novel acceptors (YO, YS, YSe) to enhance molecular properties and uncover the underlying mechanism of NCLs. The photoelectric properties of acceptors and donor (D)/acceptor interfaces are thoroughly explored by first-principles calculations. We find for the first time that introducing π-bridge at the appropriate position not only forms multiple NCLs within the backbone but also forms NCLs with the wing chain, further enhancing acceptors’ planarity and rigidity. For acceptors, NCLs contribute to stronger light harvesting and reduced energy losses. Except for the charge-transfer (CT) directions, the amounts of interfacial CT states of D/YO, D/YS, and D/YSe increase by 8%, 20%, and 36%, rspectively. Therefore, introducing multiple NCLs by π-bridge engineering into the benchmark acceptors is a possible avenue toward high-performce organic photovoltaic. Overall, our findings underscore that the incorporation of multiple NCLs through π-bridges can substantially enhance power conversion efficiencies through improved photoelectric properties, and interfacial characteristics.