Computational evaluation of optoelectronic and photophysical properties of unsymmetrical distyrylbiphenyls

Unsymmetrical distyrylbiphenyls (UDSBs) have been evaluated for their suitability for optoelectronic applications. Totally 14 UDSBs including four already reported have been investigated using DFT/TD-DFT calculations. The computed results reveal that the UDSB 1-12 can be used as good hole transport materials and UDSB 13 and 14 can be used as good electron transport materials. The newly designed UDSBs show promising optoelectronic properties and they can be used as a 'trifunctional materials' (emitter, hole and electron transport) in OLEDs. The results show that the HOMOs, LUMOs, energy gaps, ionization potentials, electron affinities, reorganization energies and exciton binding energies for these complexes are affected by different donor and acceptor groups. The photophysical characterization of the UDSBs show that, except UDSB 11-14 the absorption and emission spectra of all other molecules have pi -> pi* character as revealed by natural transition orbital (NTO) analysis. The results obtained confirm that the optical properties of UDSBs can be significantly tuned by suitable substitution and these compounds can be used to make efficient OLEDs.