Electrochemical Route to Solution-Processable Polymers of Thiophene/Selenophene Capped Didodecyloxybenzo[1,2-b:4,3-b′]dithiophene and Their Optoelectronic Properties

Abstract

Two new solution-processable polymers P1 and P2 are being reported here, which were prepared by electrochemical polymerization of thiophene and selenophene capped 7,8-didodecyloxybenzo[1,2-b:4,3-b′]dithiophene (BdT-Dod), respectively and characterized by gel permeation chromatography (GPC) and 1H NMR. The selenophene containing polymer possesses lower band gap than the thiophene analogue. Density functional theory (DFT) calculation showed the highly curved structure of the polymers and reproduced the trend in their optical band gaps. P2 showed larger bathochromic shift in the absorption spectrum from solution to film state compared to that of P1, which indicates better π-stacking interaction in the solid state for P2. In spite of having highly curved chains, the polymers successfully exhibited electrochromic switching. The exchange of the end-caps from thiophene to selenophene have manifested with higher electrochromic switching ability and better polaronic and bipolaronic features in spectroelectrochemic...