Electronic structure of dithienopyrrole, dithienothiophene and thionaphtheneindole

Dithienopyrrole (DP), Dithienothiophene (DT) and Thionaphtheneindole (TNI) are electrochromic semiconductor polymers that possess very similar electronic structure. These materials were synthesized in the middle of the nineties with the intention to obtain an improvement in the processability of the electrochromic polymers and investigate the mechanism of charge transport in the polymeric net. In this work, we investigated the electronic, conformational and spectroscopic structure of oligomers formed by the mentioned systems. Density of states and wavefunction were calculated to study the conduction mechanism in the net of these polymers through polaron defect type. We used the semiempirical methods for calculations of electronic structure of the polymers and copolymers coupled with ZINDO/Spectroscopic method to simulate the behavior of absorption for neutral and charge systems. We adopted EHT description for the conformational defects and we investigated the electrical conduction as a function of defects concentration.