Are vinyl coupled furan derivatives better than vinyl coupled thiophene derivatives for optoelectronic applications? – Answers from DFT/TDDFT calculations

In the present study, twenty three new vinyl coupled furan oligomers (VCFOs) and four already reported thiophene oligomer (VCTOs) have been investigated for potential optoelectronic properties using DFT/TDDFT calculations. Frontier molecular orbital analysis shows that the HOMO-LUMO gap of VCFO7b is the lowest among all the candidates while VCFO1a bears the highest HOMO-LUMO gap. The VCFOs display high NLO activity, exergonic type electron injection characteristics and VCTO1&3 have low NLO activity & endergonic type electron injection characteristics. Furthermore, the study investigates the influence of heterocyclic unit in HOMO-LUMO gap, NLO activity, exciton binding energy, light harvesting efficiency, electron injection properties in VCFOs& VCTOs. As a whole 21 out of 23 designed VCFOs are found to have remarkable optoelectronic properties compared to their corresponding VCTOs. Overall, our results suggest that furan oligomer tunes the optoelectronic properties to a great extent than the thiophene oligomers.