DFT investigation on D-π-A structures for n type semiconducting material for the application in organic field effect transistors

Abstract

Organic Field Effect Transistors have been widely researched since the first reported OFET in 1986 which was made of Polythiophene. The designed two molecular structures are based on D-π-A model and looked for their efficient use in Organic field effect transistors. The designed systems are named as system first (anthracene-pyrrole-propanoic acid) and system second (naphthalene-pyrrole-nitroethane) where anthracene and naphthalene are donors, pyrrole is spacer molecule, propanoic acid and nitroethane are acceptors. Both the structures were optimized under the framework of Density functional theory with B3LYP/6–31 + G(d,p) basis set on a Gaussian16W software package. The calculated charge transport parameters are hole reorganization energy λh, electron reorganization energy λe , HOMO-LUMO energy gap. Further, these have been looked upon their electric field dependence of the HOMO-LUMO energy gap and molecular electrostatic potential (MESP). The λh value for system first is 2.8 × 10-4 eV, and λe value is 4.08 × 10-5 eV. Similarly, the λh value for system second is 1.36 × 10-5 eV and λe value is 1.08 × 10-5 eV. In both the systems the electron reorganization energy λe is smaller as compared to the hole reorganization energy λh. Therefore, this is confirmed that the designed molecules can be utilized as n-type semiconductor for Organic Field Effect Transistors.