Dicyanomethylenedihydrofuran Derivatives and Heavy-Chalcogenide Chromophores as Novel Non-Fullerene Acceptors for Organic Photovoltaics: A Computational Screening Study

The search for efficient non-fullerene acceptors (NFAs) in organic photovoltaics (OPV) remains an active frontier, with state-of-the-art devices now exceeding 19% power con- version efficiency (PCE). Here we present a systematic computational screening of 58 conjugated organic molecules using density functional theory (DFT; B3LYP/STO-3G with empirical correction, verified at B3LYP/6-31G*) targeting the Shockley-Queisser (SQ) op- timal bandgap window of 1.1–1.7 eV. Our calibrated pipeline achieves an area-under- curve (AUC) of 0.839 for separating known OPV absorbers from non-OPV molecules, val- idating its predictive utility. We identify dicyanomethylenedihydrofuran (DCDHF) — a well-characterized fluorescent probe for single-molecule imaging — as an untested OPV absorber candidate with a com- puted gap of 1.55 eV (6-31G*), a dipole moment of 8.78 D, and favorable LUMO alignment for use as a non-fullerene acceptor. An exhaustive literature survey confirms this pre- diction is genuinely novel: no prior publication has explored DCDHF for photovoltaics. Screening of 19 DCDHF derivatives reveals that bridge-extended variants (thiophene insertion, bithiophene extension, phenyl bridge) systematically red-shift absorption to- ward the SQ optimum, with three derivatives achieving corrected gaps of 1.34–1.36 eV and figure-of-merit (FOM) scores approaching 1.000. We further demonstrate that S→Se→Te chalcogenide substitution in conjugated OPV back- bones provides a systematic design rule for bandgap narrowing, quantifying mean red- shifts of −0.438 eV (S→Se) and −0.787 eV (S→Te) across seven parent scaffolds. Heavy- chalcogenide variants of established OPV materials shift absorption into improved SQ territory, with six candidates entering the 1.1–1.7 eV window. Finally, we introduce bismuth-containing conjugated chromophores as a speculative but entirely novel class of OPV candidates exploiting Bi’s massive spin-orbit coupling (~600 meV splitting) for en- hanced intersystem crossing and triplet exciton harvesting. These findings expand the molecular design space for organic photovoltaic materials and identify specific experi- mental targets for validation.