Low Temperature Fabrication Of NiO_x Electrochromic Films And NiO_x/WO₃ Complementary Devices

Electrochromic smart windows make mankind see the dawn on the road of building energy saving.It can dynamically adjust and control the optical properties?reflectivity,transmittance,absorptivity,etc.?of sunlight,and its core is electrochromic devices.Complementary electrochromic devices can achieve fast complementary coloring and bleaching at low voltages,which have the advantages of low energy consumption,large optical modulation range,high coloring efficiency and long cycle life.NiO_x film is the most commonly used anodic electrochromic material as complementary electrochromic devices.In view of the disadvantages of high temperature treatment for the preparation of NiO_x thin films by chemical solution methods,In this paper,the low temperature preparation process and the mechanism of NiO_x films are studied,and the optimized NiO_x films is used as ion storage layer and complementary electrochromic layer.Glass/ITO/WO₃/PC-PMMA-LiClO₄/NiO_x/ITO/Glass complementary devices are preparated and electrochromic characteristics are explored.The research contents and results are as follows:1.NiO_x nanocrystals were prepared and NiO_x films were prepared by multiple spin-coating with NiO_x-isopropanol-deionized water suspension.The number of spin coating times,heat treatment temperature and volume ratio of isopropanol to deionized water were studied in detail.We have obtained the optimized preparation process of NiO_x films.The results show that in the case of three times spin-coating,heat treatment at 150?in air and the volume ratio of isopropanol to deionized water is 1:2,NiO_x films have the best electrochromic properties.At the wavelength of 550nm,the transmittance modulation range is 62.3%,the coloring/bleaching response time is 4 s/3 s,the coloring efficiency is 42.8 cm²/C and the film has excellent cycle persistence in Li⁺-based electrolyte.2.Compared with RF magnetron reactive sputtering,The WO3 films prepared by resistance thermal evaporation have better electrochromic properties.At the wavelength of 550 nm,the optical transmittance modulation range is 54.1%,the coloring/bleaching response time is 34 s/4 s,the coloring efficiency is 48.6 cm²/C.3.The electrochromic properties of Glass/ITO/WO₃/PC-PMMA-LiClO₄/NiO_x/ITO/Glass electrochromic devices are as follows:At the wavelength of 700 nm,the optical transmittance modulation range is 47.9%;At the wavelength of 550 nm,the optical transmittance modulation range is 39.4%,the coloring/bleaching response time is 40 s/14 s,the coloring efficiency is 56.1 cm²/C.