Prediction of electronic properties of EDOT containing conjugated polymers using semiempirical methods

To understand the electrochromic and electronic properties of ethylenedioxythiophene(EDOT)/phenylene linked polymers, twelve 1,4-bis[2-(3,4-ethylenedioxy) thienyl]benzene (BEDOT-B) based oligomers were studied using AMI at the RHF-SCF level within GAMESS. The monomers were also determined at the RHF/6-31G* double-zeta valence basis set level within GAMESS. The monomers and polymers have been synthesized to verify the results by electrochemical, spectroscopic, and x-ray structure determination. Electron withdrawing groups such as F, CN, and NO, were used to increase the band gap while retaining low oxidation potentials. We were able to predict the band gap to within 0.1 eV using an additive coefficient of -0.87 eV for all polymers.