The Preparation And Mechanism Study Of The Electrochromic Device Based On Conducting Polymer

Due to their unique optical-electronic properties, electrochromic materials and devices have applications in various fields, such as novel display, electro-ink, information storage device, military camouflage, smart window and so on. In this dissertation, each layer material of electrochromic device is studied, and we prepare poly(3,4-dibromothiophene) (PDBrTh) electrochromic film,TiO₂-CeO₂ composite films, PMMA-based composite gel electrolytes. Finally we assemble the symmetric and asymmetric large-area ECD, the parallel structure ECD, double-color-layer ECD and flexible ECD.High-quality poly(3,4-dibromothiophene)(PDBrTh) film is prepared electrochemically in boron trifluoride diethyl etherate. The resulted PDBrTh film can change between vivid red and blue reversiblly, and the fastest response time is 1.21 seconds, cycle life up to 1800 laps.Using nanosized rare earth oxides as fillers, and Propylene Carbonate (PC) as organic solvent, the composite polymer electrolyte films PMMA-PC-LiClO4-χwt% was prepared by sol-gel technique. We research conductivity, crystal morphology, chemical structure by SEM, XRD, IR, et al.It is found that the highest ionic conductivity of 7.4×10-4S/cm is achieved with the Y2O3 content of 1.3wt%, approximately 3 times than before. In addition, it can effectively prevent formation of air bubbles.TiO₂-CeO₂ composite films on ITO glass substrate were successfully prepared by sol-gel process. The structure and properties of the films were characterized by XRD, SEM, UV-vis transmitted spectrum and Cyclic voltammetry, respectively. The results show that TiO₂-CeO₂ thin films with the capacity of charge storage of 9.46 mC·cm-2 and the cycle of reversible K of 95%.Using the above materials, we assemble the symmetric and asymmetric large area electrochromic devices, with a contrast ratio of 23%, response time of 0.9s, and analyze the mechanism of its color. We assemble a parallel structured ECD that the ion is transferd parallelly to the electrochromic material. Its' open memory is above 9h, used in colored lithium-ion batteries. Besides, a double layer ECD is assembled, the results show the contrast, response time has been enhanced, and the color superimposition is found also. In addition, we also try to prepare a polyaniline-based flexible electrochromic devices, and obtain a green-blue reversible flexible ECD, and the results in useful for the further study of flexible display devices.