Two New Near-Infrared Switchable Electrochromic Bithiophenes Derivatives Based on 4-Methoxytriphenylamine Unit and Their Application for Electrochromic Devices

Two novel triphenylamine-containing thiophene derivative monomers, 4-methoxy-4',4"-di(thiophen-2-yl)triphenylamine (MTTPA) and 4-methoxy-4',4"-di(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)triphenylamine (METPA), were successfully synthesized. The corresponding polymers including PMTTPA and PMETPA were electrochemically synthesized and characterized by cyclic voltammetry (CV), UV-vis-NIR spectroscopy and scanning electron microscopy (SEM). Electrochemical and spectroelectrochemical analysis showed that two polymers had reversible redox behavior and multi-electrochromic property. Dynamic electrochromic experiments suggested that both the polymers had rapid switching time, high coloration efficiency, and high contrast of optical transmittance changes (Delta T%) in the NIR region (55.5% at 1280 nm for PMTTPA, 77.6% at 1200 nm for PMETPA). The dual-type electrochromic device based on PMTTPA film (or PMETPA film) was constructed and characterized as well. Both of them revealed excellent properties. (C) 2014 The Electrochemical Society. All rights reserved.