Addition of acceptor moiety toward Quinoxaline-based conjugated framework of chromophores for highly efficient organic solar cells

Abstract

The quantum contemplation of highly unsaturated D-π-A type renewed chromophores (TQ41-TQ45) constructed on quinoxaline core-based model TQ4 are predicted to suggest novel photovoltaic constituents for the application of organic solar cells. The model TQ4 was amended by the replacement of terminal groups with conjugated acceptors via thiophene to design five novel chromophores and their structural as well as optoelectronic attributes were calculated at selected DFT method PBEPBE/6-31G (d, p) level of theory. FMO study revealed that high charge transfer occurred between HOMO-LUMO by the reduction of energy gap up to 0.59 eV (for TQ44) which is quite low from the model TQ4 (2.04 eV). Absorption profile unveiled that the maximum absorption of all the designed chromophores in dichloromethane was in visible and near IR region exhibiting bathochromic shift up to 916 nm that is higher than the reference TQ4 (505 nm). Higher values of dipole moment by novel chromophores up to 16.85 D than reference (1.66 D) suggested good solvation and better molecular packing. ESP analysis revealed electron distribution on various parts of the molecules by colored maps that is found to be effective for better ICT. TDM plots depicted density of electron transitions on various molecular sites by the absorption of light. RE values of electron and hole for novel molecules proved to be highly efficient that enhanced the charge mobilities and prevented charge recombination. Finally, open circuit voltage of all the studied chromophores was calculated by scaling our designed donors to the well-known acceptor PC71BM that is very effective for the fabrication of elite organic solar cells.