A DFT study on the electronic and photophysical properties of biphenylyl/thiophene derivatives for organic light emitting transistors

Abstract

A theoretical study was carried out to understand the geometrical, electronic and optical properties of bipheylyl/thiophene based molecular system. For that, density functional theory along with classical Marcus charge transfer theory and time-dependent potentials were used. The results indicate that the structure-property relationship between the molecular parameters and ionization energy, electron affinity, reorganization energy, charge transfer integrals, mobility, energy gap, optical absorption and transition dipole moments. Low lying HOMO values and lower bandgaps of the molecules offer a higher charge transport in the systems and 5,5″-bis(4-biphenylyl)-2,2′:5′,2″-terthiophene (BP3T) molecule shows the maximum hole and electron mobility, 0.81 cm2 V−1 S−1 and 0.17 cm2 V−1 S−1, respectively. The results have shown that all the title compounds can be fabricated as ambipolar organic semiconductor materials and can be considered for the fabrication of efficient organic light emitting transistors.