DFT investigation of strong acceptor molecules

This paper describes the creation of three near-infrared (NIR) acceptors, namely BCDT, BCDT-4F, and BCDT-4Cl, with the A−D−C−D−A (acceptor−donor−core−donor−acceptor)-type conformation. The acceptors use intramolecular noncovalent interactions to ensure the conservation of the molecular shape of the unfused complexes. Quantifications of EHOMO, ELUMO, Eg, λmax, Ex, and ESP have been calculated to illustrate the optoelectronic and structure-related properties. In the gas phase, the non-fullerene acceptor BCDT-4Cl has shown the lowest band gap energy of 1.87 eV and the lowest excitation energy of 1.66 eV. Thus, it is anticipated that BCDT-4Cl will emerge as a very viable candidate for future organic non-fullerene acceptors. We have calculated the dipole moments of the specified acceptors for both the ground state (μg) and the excited state (μe). Notably, BCDT-4Cl had the highest dipole moment values, namely μg = 5.66 and μe = 6.86 Debye. The predicted λmax value of 734 nm obtained by Density Functional Theory (DFT) for the reference molecule is consistent with the actual λmax value of 784 nm. The synthesised compounds have acute sensitivity in the near-infrared region and show a red shift in the absorption spectra, therefore covering a broader spectrum of wavelengths ranging from 730 to 7743 nm.