Abstract
Seven small molecule donors (S1–S7) have been theoretically formulated by the end-capped modeling of acceptors of reference SR. Through density functional and its time-dependent theory, different photo-physical, morphological, and opto-electronic aspects of the newly reported molecules were analyzed with reference to the SR molecule. Amongst the different studied features were the absorption maxima (λmax), transition density matrix, frontier molecular orbitals, reorganization energies of hole and electron, excitation energies, bandgaps, fill factor, and open circuit voltage (VOC), etc. Individually, the S4 molecule had the smallest bandgap and electron reorganization energy, the highest ionization potential and λmax, as well as the smallest excitation energy in the analyzed gas and chloroform phases. While the smallest interaction coefficient was seen to be of S1. The VOC of all the donor molecules computed with respect to PC61BM acceptor revealed the greatest VOC and fill factor of S1 and S4 molecules. So, it could be understood that these molecules, with special reference to S1 and S4, might outperform SR in a variety of ways, and hence are suggested to experimentalists for future innovations of organic photovoltaic cells.
•By substituting the terminal acceptors of Spiro-F (SR), seven small molecule donors (S1–S7) were synthesized.•Compared to the reference molecule SR, all newly designed molecules have a smaller bandgap and a higher λmax.•The lower excitation energies of the newly formulated molecules illustrate their enhanced intramolecular charge transfer.•The VOC of S1 and S4 was the highest when calculated with respect to PC61BM acceptor.