Novel multielectrochromic and fast-switching copolymers based on methoxybenzene and thiophene via electrochemical copolymerization in boron trifluoride diethyl etherate

A series of conducting copolymers based on methoxybenzene and thiophene are prepared via direct anodic oxidation of the mixtures of methoxybenzene and thiophene in boron trifluoride diethyl etherate (BFEE). Feed ratio of methoxybenzene/thiophene plays great effect on the electrochromic performance of the copolymers, which can exhibit multicolor and tunable electrochromism. The copolymer prepared with methoxybenzene/thiophene feed ratio of 1/8 exhibits excellent electrochromic properties which presents golden color, yellow green, green blue and dark blue under various applied potentials. The optical contrast and response time (monitored at the absorption peak of 474 nm) are 15.1% and 0.6s, respectively. The corresponding coloration efficiency is calculated as 307 cm2/C. In addition, the copolymer shows decent optical stability which only loses optical contrast of 1.4% at 474 nm after 200steps. All of these indicate that high-performance electrochromic materials can be prepared via simply commercial available monomers such as thiophene and methoxybenzene.