Electronic properties of polythiophene investigated by semiempirical methods

Abstract EN

A systematic investigation of the electronic structures of polythiophene oligomers (n T where n is the number of thiophene rings) has been performed using the semi empirical methods AM1 (Austim Model 1) and MNDO (Modified Neglect of Diatomic Overlap).The equilibrium geometrical structures, heats of formation, HOMO-LUMO gap energies, ionization potentials and affinity potentials of n T have been studied.

The calculation results obtained by these semi empirical methods show that the HOMO-LUMO gap energies and the oligomers stability decrease with increasing thiophene rings.

The ionization potentials decrease and the affinity potentials increase with increasing thiophene rings.

It has been found that the semi empirical method in combination with a simple linear relationship can be used to predict the energy band gap.