Impact of symmetry breaking on the performance of non-fullerene acceptors (NFAs) for photo and thermally stable organic solar cells (OSCs): A DFT-based interrogation and investigation

[Display omitted] •New NFAs have been designed by employing advanced quantum chemical techniques.•All the designed molecules have shown narrow band gaps.•SGS-1 to SGS-4 expressed high mobility of the hole and electron.•Low excitation and binding energy values have been observed.•All the designed systems are efficient for high-performance organic solar cells. Simultaneous enhancement in the fill factor (FF) and power conversion efficiency (PCE) is a crucial task for the development of photovoltaic (PV) devices. In addition, symmetrical acceptor molecules lack photo and thermal stability due to low extinction coefficient and dipole moment. Breaking of symmetry in typical fullerene-free acceptors brings high values of dipole moments along with crystalline features. In this regard, a series of new acceptor molecules have been designed by deep end-capped remodeling of the IPC-BEH-IC2F. Newly remodeled systems disclosed high values of electronic charge shifting and perfect molecular packing. The impact of symmetry breaking is examined through density functional theory (DFT) and time-dependent density functional theory (TDDFT) at CAM-B3LYP/6-311G(d,p) level. Photovoltaic and geometric aspects like frontier molecular orbitals (FMOs), excitation energy, open circuit voltage (Voc), FF%, and PCE have been computed theoretically. Reshaped systems expressed high mobilities of the electrons and holes towards the metal electrodes together with easy excitation of the exciton. High Voc enhances the FF% and PCE in the SGS-1 to SGS-4. Results of all analyses showed that SGS-1 to SGS-4 are well-designed systems for the development of the highly efficient active layer for OSCs.