Density functional theory and time-dependent density functional theory studies on optoelectronic properties of fused heterocycles with cyclooctatetraene

We establish a structure-property relation for the system having a cyclooctatetraene (COT) ring fused with four five-membered heterocyclic rings. The two five-membered heterocycles selected are furan and selenophene and their fused structure with COT is known as cyclooctatetrafuran (COF) and cyclooctatetraselenophene (COSe), respectively. We found 15 geometrical isomers of each COF and COSe and their structural stability and optoelectronic properties have been evaluated by quantum chemical simulations. The density functional theory (DFT) and time-dependent DFT simulations were employed for a systematic review of all isomers. Electronic excitations, hole reorganization energies, electron reorganization energies, ionization potentials, and electron affinities, of all the isomers, were reported. Based on our comparative study, it is shown that one of the isomers is suggested as a better charge transport material.