Construction And Performances Of Electrochromic Devices Based On Tungsten Oxide

Electrochromism has been widely concerned since it was discovered.In the beginning,electrochromic(EC)devices were mainly applied in the Smart window and anti-glare rearview mirror,and the EC devices were mainly rigid devices and based on the sandwich structure.In the later development process,due to the requirement for the flexible displays and smart clothing,flexible EC devices gradually attract people's interest,and the EC devices began to change from rigid devices into flexible films.In recent years,the research of EC fibers are urgently required for infrared camouflage and sensing.The problem is how to construct EC devices with stable structure and excellent performance to ensure that they can satisfy the demands of the developing society.This paper focus on the construction of electrochromic devices with different structures,and mainly studies the following three aspects.Here,the construction and performance of electrochromic devices with different structures were investigated as follows:Firstly,the amorphous tungsten oxide was obtained using alcoholysis,and sprayed on the electrode.The rigid EC device was constructed by combining the EC electrode with the gel electrolyte.The effect of device area on the performance of EC devices were also measured.For the EC device with an area of 10×10 cm~2,the coloring efficiency reached 125.2 cm~2/C.The optical modulation range was 40%under the volage of-3.0 V,and 80%of the optical modulation range can be maintained after 200 cycles.In addition,the EC devices enched by the laser engraving technology realized color changes by region.It provides a new way to solve the problem of performance degradation when the device area is enlarged.Secondly,in order to satify the demands of flexible EC device in flexible display and other fields,the flexible electrochromic film devices were constructed by using the gel electrolyte in the above chapter combined with the poly(3,4-ethylene dioxythiophene)polystyrene sulfonate/tungsten oxide nanowires composite EC layer.The colored and bleached time of the flexible device can reach 32.8 s and 20.5 s,respectively,and the optical modulation range can reach 32.2%.After 200 cycles,the optical modulation range maintained 75%,and after 200bending cycles,the optical modulation range maintained 85%.In this paper,the preparation method of the composite EC layer is simple,low cost and has the potential of practical application.Finally,the composite EC layer described in the previous chapter was coated on the conductive copper wire by drop-coating,and the electrochromic fiber was constructed by combining poly(vinylidene fluoride-co-hexafluoropropylene)gel electrolyte.The reflectance contrast of the EC fiber was 40%under the voltage of-1.5 V,and the color changed from White to Blue.The voltammetry curve hardly changed after 200 cycles,indicating great stability of EC fibers.A preparation method of long-range EC fiber was proposed in this paper.Through continuous mechanical operation,the assembling speed of fiber could be greatly improved,and the length of EC fibers could be effectively improved,which laid a certain foundation for industrial production and application.