Impact of end-capped engineering on the optoelectronic characteristics of pyrene-based non-fullerene acceptors for organic photovoltaics

Pyrene-based molecules are being explored as prospective fullerene-free acceptors for organic solar cells (OSCs), due to their easy accessibility, structural planarity, and excellent electron delocalization. In this work, we successfully designed and analyzed pyrene-based acceptor materials (QL1–QL8) to investigate their photophysical and electro-optical parameters. Various geometric parameters were computed at the MPW1PW91/6-31G(d,p). Advanced quantum chemical approaches were employed to characterize the molecules. All the tailored molecules (QL1–QL8) exhibit a lower bandgap than the reference (R), signifying their superiority. Among these, QL8 was found to have a maximum absorption (λ_max) at 791.37 nm and an optical bandgap (E_LUMO ? E_HOMO) minimum of 2.11 eV. Redshifted absorption spectra are observed in both gaseous and solvent phases for all the designed (QL1–QL8) molecules in contrast to R. Among these, QL4 exhibits the highest light harvesting efficiency (0.9826), and open-circuit voltage. A detailed donor–acceptor investigation of QL8/PBDB-T revealed the marvelous charge switching at the donor–acceptor interface. The approach used in this study is anticipated to facilitate the manufacturing of highly efficient OSC molecules.