Photophysical and charge-transport properties of hole-blocking material-TAZ: A theoretical study

The hole/exciton blocking material (3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole) (TAZ) plays a crucial role in the light emitting diode devices by increasing the possibility of charge recombination. Its photophysical and charge transport properties have been investigated by means of quantum chemical approach. The ground state and ionic structures of TAZ were optimized by density functional theory (DFT) calculation, while the excited-state structure was obtained with configuration interaction singlet (CIS) method. The molecular composition analysis of frontier molecular orbitals, reorganization energy and density of states (DOS) indicate that TAZ is in favor of electron transport in its neutral and negative charged states rather than positive charged state.