| Tungsten oxide is probably the most promising one of various electrochromic materials due to its excellent electrochromic properties including good color efficiency, excellent response speed, long term stability and large variation of optical modulation.WO3 films were prepared by mid-frequency dual target magnetron sputtering system. The structure and electrochromic properties of the films were analyzed by X-Ray diffraction, Raman Spectroscopy. Spectrophotometer, cyclic chronoamperometry and atomic force microscopy .The result show that the as-deposited WO3 films are amorphous. WO3 crystalline are formed at 300 - 400 ℃ . The films deposited at high oxygen content show good electrochromic property after annealing at 200℃. And the variation of average transmittance difference between the bleached and colored state can reach 60% in the wavelength range between 500nm and 800nm.Ti-doped WO3 films were prepared by mid-frequency dual-target magnetron sputtering method. The results indicate that the crystallinity decrease after doping titanium, And the channels for ions injecting and extracting increase. Accordingly, the responding speed of doping 5.1% of titanium gets faster and its circle life increases more than four times. In the colored state, the intensity of peak corresponding to W-O-W bonds decrease, and the intensity of peak corresponding to W=O bonds increase, since W-O-W bonds break down for Li+ion injecting and more W=O bonds form. It is more convenient for Li+ ions to inject into film corresponding to the doped film than undoped one because of more W-O-W bonds breaking down.The structure of "glass/ ITO/ WO3/ electrolyte /ITO/ glass" was fabricated, which has good color efficiency, even the variation of average transmittance difference between the bleached and colored state can reach 45% in the wavelength range between 600nm and 800nm. The color responding time of the device is about 20 second, and its bleach responding time is about 10 second.
|
PDF Full Text Request