Electrochimica Acta, Vol.146, 231-241, 2014
Three donor-acceptor polymeric electrochromic materials employing 2,3-bis(4-(decyloxy)phenyl)pyrido[4,3-b]pyrazine as acceptor unit and thiophene derivatives as donor units
In this study, 5,8-dibromo-2,3-bis(4-(decyloxy) phenyl) pyrido[4,3-b]pyrazine was synthesized and used as the acceptor unit, which then be coupled with three thiophene derivatives (3-methylthiophen, 3-methoxythiophen and 3,4-dimethoxythiophen) to give rise to three novel monomers, 2,3-bis(3-methoxythiophen and 3,4-dimethoxythiophen) to give rise to three novel monomers, 2,3-bis (4-decyloxy) phenyl)-5,8-bis(3-methylthiophen-2-yl) pyrido[4,3-b]pyrazine(M1), 2,3-bis(4-decyloxy) phenyl)-5,8-bis(3-methoxylthiophen-2-yl) pyrido[4,3-b]pyrazine (M2) and 2,3-bis(4-decyloxy) phenyl)5,8-bis(3,4-dimethoxylthiophen-2-yl) pyrido [4,3-b]pyrazine(M3). The corresponding polymers P1, P2, P3 were obtained by electropolymerization method. These polymers were characterized in terms of their spectroelectrochemical and electrochemical properties by cyclic voltammetry and UV-Vis-NIR spectroscopy. The band gaps of the polymers were calculated based on the spectroelectrochemistry analysis, and were 1.39 eV, 1.136 eV and 1.25 eV for P1, P2, P3, respectively. Electrochromic investigations showed that P1 switched between blue and colorless transmissive state, P2 switched between green to transmissive light gray color, and P3 switched between blue to transmissive light brown color. Electrochromic switching studies showed that all three polymers exhibit high coloration efficiency, fast response time, and express more than 45% change in the transmittance in the near-IR region, which could make these polymers useful in applications in NIR electrochromic devices. (C) 2014 Elsevier Ltd. All rights reserved.