The Preparation And Performance Research Of The Electrochromic Device Based On Conducting Polymer

The electrochromic devices (ECDs), which exhibit reversible color change through electrochemical redox reaction, have attracted considerable research interests because of their potential applications in various electronic and optical devices. In this thesis, the preparation technologies about the corresponding materials for the ECDs were investigated.We used aniline as the electronic material, water as solvent, dodecylbenzenesulfonic acid as dopant and emulsifier, ammonium persulfate as oxidant through in-situ emulsion polymerization to prepare polyaniline-based emulsion, which was used to prepare the polyaniline film by spin-coating. The film-forming property of PANI was adjusted by using different types and content of polyvinyl alcohol during the in-situ emulsion polymerization process. It was found that PVA1750+50 was a good film-forming additive with an addition of 2.8%, resultly a polyaniline film present a well film-forming properties and good electrochromic properties.Titanium dioxide sol was prepared by using tetrabutyl titanate as the precursor via sol-gel method. The different layers of titanium dioxide films were prepared by dip-coating method, and the resulted films were characterized by XRD, SEM, UV, cyclic voltammetry and so on. Results show that the number of titanium dioxide films is in 30 to 60 layer. Besides, the typical anatase titanium dioxide crystal was formed after heat-treated at 500℃, which had the thickness of about 200 nm with the uniform particle size diameter of about 10-20 nm. The films had strong ion storage capacity, steady extraction and embedding rates of lithium-ion, suitably used as the ion storage layer.The gel electrolyte with PMMA-based system with a conductivity of 10-3S/cm and the optical transmittance more than 85% was prepared, which was suitable used as the electrolyte of electrochromic device. In addition, the symmetrical structure electrochromic device (SSECD) and the asymmetric structure electrochromic device (ASECD) were assembled with the as-prepared polyaniline, titanium dioxide and electrolytes. The in-situ electrochemical UV-visible spectroscopy investigation found that the maximum transmission rate difference of ASECD was 43.3%, nearly about twice of SSECD. Meanwhile, ASECD took on reversible color variation among yellow (-1.4 V), green (0 V) and blue (1.4 V), and had faster coloring/fading response time (0.8 s), but its lifetime was little less than that of the SSECD, and need a further improvement.Moreover, a flexible electrochromic device was explorated and studied, and some preliminary results were obtained.