Designing indaceno thiophene-based three new molecules containing non-fullerene acceptors as strong electron withdrawing groups with DFT approaches.

Nowadays, scientists are trying to develop low-cost fullerene free acceptors for small organic photovoltaic cells in order to overcome the limitations of fullerene derivatives. Current research work deals with theoretical study on three non-fullerene acceptors based on indaceno, dithiophene core, and thiophene bridge units linked with dissimilar end non-fullerene groups which act as strong acceptor moieties. Different optoelectronic characteristics of the designed molecules were calculated and compared with the reference compound R (indaceno dithiophene-based fused ring acceptor) which is recently reported. Results shows that C2 and C3 exhibit broad absorption spectrum and lower band gap whereas C2 and C1 exhibit highest open-circuit voltages VOC value with B3LYP and MPW1PW91 functionals respectively as compared with the R. All designed molecules have high dipole moment values, lower value of hole reorganization energy λh than electron reorganization energy λe which reflects that our designed acceptor molecules are good candidates for organic photovoltaics. Graphical abstract Absorption spectra of R and three designed non-fullerene acceptors with strong absorption band in the visible region of solar cells spectrum.