Theoretical Insights into the Electronic Properties and Charge Transfer Dynamics of Y6/PBDF‐NS Organic Solar Cells

Understanding how end‐group engineering modulates the electronic structure and interfacial behavior of non‐fullerene acceptors is essential for advancing the design of high‐efficiency organic solar cells. In this work, we employ DFT and TD‐DFT calculations to investigate the optical and electronic properties of PBDF‐NS in combination with three Y6‐based acceptors (Y6, Y6‐IN, and Y6‐NO). This study presents the first theoretical exploration of PBDF‐NS paired with the nitrated derivatives Y6‐IN and Y6‐NO, which offers fresh perspectives on how controlled end‐group modification governs donor–acceptor interactions. Three adsorption configurations were examined for each system, revealing that Y6‐NO exhibits both the strongest (most negative) adsorption energy (−2.518 eV) and smallest HOMO–LUMO energy gap among the investigated donor acceptor complex systems (4.834 eV), indicating enhanced charge‐transfer propensity relative to pristine Y6. Furthermore, end‐group nitration induces favorable shifts in electronic alignment and improves interfacial charge redistribution, collectively promoting more efficient exciton dissociation. These findings demonstrate that targeted modification of Y6 end groups is an effective strategy for tuning interfacial energetics and optimizing the performance of emerging PBDF‐NS–based organic solar cells.