Study of electrical conductivity and thermochemical stability of oligo(3,4-ethylenedioxythiophene) at temperature range of 50–400 K

Abstract

Abstract A quantum-chemical approach was carried out on a series of oligomers made up of the 3,4-ethylenedioxythiophene (EDOT) in view of their potential applications for use as the main component in the redox super-capacitor and organic light-emitting diodes. The density functional theory was performed in the B3LYP/6-311++G(d,p) level on the dimer up to the octamer chains of oligo(EDOT) in the neutral and both ionic states. The extent of π-conjugation length, lower HOMO–LUMO band gap, charge delocalization along backbone, and bathochromic shift in the UV-visible spectra for oligo(EDOT) showed that the ethylenedioxy substitution remarkably improved the poly(EDOT) characteristics. The temperature dependency of electrical conductivity and thermodynamic stability for oligo(EDOT) was studied in the temperature range of 50–400 K. The calculated conductivity for poly(EDOT) was compared with the available experimental measurements. More satisfactory properties were obtained in both the p- and n-doped phases, reflecting the electron and hole transport facilities for conductivity.