Application of Newly Designed Y‐Series Nonfullerene Acceptors for High‐Efficient Organic Solar Cells

Abstract The electron acceptor materials in organic solar cells (OSCs) play an essential role in enhancing power conversion efficiency (PCE). Although Y6‐based nonfullerene acceptors (NFAs) have shown fascinating experimental progress, molecular engineering is an effective strategy for further improvement of PCE. Herein, a series of Y6‐based symmetric and asymmetric NFAs are designed using the Y6‐based core with various end‐group units. The impact of end group units on geometric, electronic, and excited state properties of NFAs is studied using state‐of‐the‐art density functional theory methods. Various selection criteria are used to screen potential NFAs among 18 newly designed NFAs. The interfacial electronic properties between conjugated polymer and NFAs are thoroughly studied in the excited state to analyze the potentiality of screened NFAs. More importantly, the screened asymmetric NFAs have shown improved charge mobilities with a lower charge recombination rate than prototype FRY6. It is noticed that screened NFAs have multiple charge transfer pathways through direct excitation, hot excitons, and intermolecular electric field mechanisms. Overall, the results obtained from this computational study give useful guidance for developing NFAs for high‐performance OSCs.