| Electrochromic devices with environmental-friendly characteristics have shown widely applications on electrochromic smart windows,flexible display,anti-glare rearview mirrors and many other fields.However,polymer electrochromic materials can only display limited colors,multicolor or even full-color display has always been the hot point of electrochromic research.With the development of electrochromic materials,electrolyte layer as the key component of electrochromic devices plays an important role in improving the performance of electrochromic devices.Moreover,the poor stability of polymer electrochromic devices restricts the commercial applications of electrochromic devices.In the second chapter,poly?3,4-ethylenedioxythiophene??PEDOT?and poly?4,4',4''-tris[4-?2-bithienyl?pheny]a mine??PTBTPA?films were prepared by electrochemical polymerization.By adjusting the parameters of electrochemical polymerization,PEDOT and PTBTPA composite films with laminated structures were prepared.Infrared spectroscopy?FT-IR?and field emission scanning electron microscopy?SEM?confirmed that the composite films were successfully prepared.The results of electrochromic performance test show that the composite film can produce a variety of color change from orange to blue and dark green with good electrochemical activity and high optical contrast at the same time,compared with the color changes of PTBTPA film?only orange to dark grey?and PEDOT film?dark blue to light blue?.Therefore,this simple and effective idea of laminated composites provides a new way for the design and fabrication of multicolor and even panchromatic display PEC materials.In the third Chapter,five different solid polymer electrolytes were prepared by adding different kinds of imidazole ionic liquids as conductive media and plasticizers into the polymer matrix.The results show that when 1-butyl-3-methylimidazolium?[BMIM]OTF?was added to the electrolyte system,the polymethyl methacrylate,lithium tetrafluoroborate and 1-butyl-3-methylimidazolium triflate?PMMA+LiBF4+[BMIM]OTF?system has the best comprehensive performance and regulation compared with the solid electrolyte system?PMMA+LiBF4?.We also prepared the solid electrolytes by controling the ratio of ionic liquid[BMIM]OTF and the polymer matrix.The results show that when the mass ratio of PMMA to[BMIM]OTF is 1:2,the electrolyte?[BMIM]OTF2?exhibits the best ionic conductivity(3.4×10-4 S/cm)and high transmittance?97%?.In addition,PTBTPA/[BMIM]OTF2/PEDOT electrochromic devices were assembled by using the solid electrolyte as the electrolyte layer.It is found that the device can achieve reversible color changes from orange to blue at different voltages,high optical contrast?54.6%?,fast response time?0.57 s?and good cyclic stability.In the fourth Chapter,PTBTPA films obtained via electrochemically polymerized as electrochromic layer and PEDOT:PSS films with different thickness?prepared by spin-coating or blade coating method?as ion storage layer were used to assemble electrochromic devices.All the charge capacity of PTBTPA films and PEDOT:PSS films were carried out by chronocoulometry test.The results indicate that PEDOT:PSS film prepared by spin-coating possesses the similar charge capacity as that of PTBTPA film while the PEDOT:PSS film prepared by blade coating shows much larger charge capacity than that of PTBTPA film.Furthurmore,the electrochromic device assembled with PTBTPA film and PEDOT:PSS obtained by spin-coating exhibits better cyclic stability than that of the device assembled with PTBTPA film and PEDOT:PSS obtained by blade-coating.Therefore,it is concluded that the charge capacity balance betweent the electrochromic layer and ion storage layer plays an essential role in the cyclic stability of the electrochromic device. |
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