Preparation of an EDOT-based polymer: optoelectronic properties and electrochromic device application

Here we present the synthesis, characterization and electropolymerization of a new EDOT-based monomer; 5,10-dihydrobenzo[f] thieno[3,4-b][1,4] dioxocine (DTD). Electrochemical polymerization of DTD was performed potentiostatically by using dichloromethane (DCM) as solvent and tetrabutylammonium hexafluorophosphate (TBPF6) as supporting electrolyte. Homopolymer [P(DTD)] films and copolymer [P(DTD-co-TPA)] films of DTD prepared by using 4-(2,5-di(thiophen-2-yl)-1Hpyrrole- 1-yl) butane-1-amine (TPA) were characterized via CV and UV-vis spectroscopy. Spectroelectrochemical analysis of P(DTD) revealed electronic transitions at 585 nm (pi-pi* transition) with an electronic band gap of 1.69 eV. Electrochromic studies revealed that P(DTD) has competitive properties to EDOT. Furthermore, a dual-type complementary colored polymer electrochromic device based on P(DTD) and P(TPA) was constructed in sandwich configuration. Spectroelectrochemical studies revealed that the oxidized state of the device shows a blue color whereas it is yellow in the reduced state. The maximum contrast (Delta% T) and switching time of the device were measured as 25.5% and 0.5 s for 385 nm and 21% and 1.0 s for 550 nm.