Charge transport and optical properties of discotic liquid crystalline molecules THDDP and substituted THDP

摘要

The theoretical investigations have been carried out on the discotic liquid crystalline molecules, 2,3,6,7-tetrakis-hexyloxy-9,16-diaza-dibenzo[a,c] phenazine (THDDP) and different substituted 2,3,6,7-tetrakis-hexyloxy-dibenzo[a, c]phenazine (THDP) to study their charge transport and optical properties. The key parameters of charge transport such as charge transfer integrals and site energies have been calculated from the matrix elements of Kohn-Sham Hamiltonian. The reorganization energy for the presence of excess charge and the rate of charge transfer calculated from Marcus theory have been used to find the mobility of the charge carrier in the studied molecules. The results show that the substitution and stacking angle change strongly affect the charge carrier mobility in π-stacked THDDP and substituted THDP molecules. Molecular dynamics simulations have been performed to find the most favorable conformation. The time-dependent density functional theory (TDDFT) calculations reveal that for these molecules the different substitutions does not alter the main features of optical properties and the molecules may be used as blue light emitters.