The Synthetic Containing Alternating Bithiophenes Derivatives And Triphenylamine Unit And Their Application For Electrochromic Devices

As a kind of novel intelligent materials, electrochromic materials have been drawnlots of scientific researchers of the study. Conducting polymers have been considered aspromising materials due to their good electrochromic properties.Triphenylamine-containing thiophene derivative have a good application prospect inorganic and polymeric optoelectronic devices, because of them high conductivity, strongstability, and tunable band-gap. In this article, we synthesized a variety of monomers viacoupling reaction and a variety of corresponding polymers by electrochemicallysynthesized, and studied the photoelectric properties of them.Six novel monomers (CTTPA，CETPA，MTTPA，METPA，CMTPA and MMTPA)were successfully synthesized via coupling reaction. Characterizations of all polymerswere performed by cyclic voltammetry (CV), UV-vis-NIR spectroscopy and scanningelectron microscopy (SEM). Spectroelectrochemical analysis revealed that the polymersfilm (CTTPA, CETPA and CMTPA) had good electrochromic properties and exhibitedmulti-electrochromic behavior. The polymer films showed reversible electrochemicaloxidation accompanied by strong color changes with a high contrast ratio, rapid switchingtime and high coloration efficiency. Electrochemical and spectroelectrochemical analysisshowed that three polymers (MTTPA, METPA and MMTPA) had reversible redoxbehavior and multi-electrochromic property. Dynamic electrochromic experimentssuggested that all the polymers had rapid switching time, high coloration efficiency, andhigh contrast of optical transmittance changes (T%) in the NIR region (55.5%at1280nmfor PMTTPA,77.6%at1200nm for PMETPA). The experimental results showed that theycould realize the tunableness of the band gap. And it was interesting to find that slightstructural difference of the polymers could result in the variation of the optical andelectronic properties. All polymers had high optical contrast, fast response time,satisfactory coloration efficiency and good stability. Polymers, which contained3,4-ethylenedioxythiophene (EDOT) or3-methoxythiophene, had more obvious electrochromic properties.For further research of electrochromic devices conducting triphenylamine-containingthiophene derivative units in the application of organic optoelectronic devices, this paperconstructed six electrochromic devices, PCTTPA/PEDOT, PCETPA/PEDOT,PMTTPA/PEDOT, PMETPA/PEDOT, PCMTPA/PEDOT and PMMTPA/PEDOT. ThePEDOT was cathodic materials, six other copolymer were the anodic material. Besides, itis interesting to find that the PCTTPA/PEDOT device and PCETPA/PEDOT devicedisplayed two colors (yellow, dark-blue and green, blue) belonging to primary colors,respectively. The corresponding devices based on PCMTPA or MMTPA and PEDOTshowed reasonable optical contrast (ΔT%), fast response time and excellent cyclicvoltammetry stability; hence they are promising candidates for various applications. Thedual-type electrochromic device based on PMTTPA film (or PMETPA film) wasconstructed and characterized as well. Both of them revealed excellent properties.Electrochromic devices (ECDs) had good photoelectrical properties, and this showed thatthey had the well commercial application prospect.