Optical Switching and Color Changing Properties of VO2 Films on Muscovite Substrate

VO2 films on muscovite substrate were fabricated by inorganic sol-gel method and the following thermal treatment. The films were characterized by X-ray diffraction, scanning electron microscope (SEM), fourier transform infrared spectrophotometer (FTIR) and color difference (ΔE*). The FTIR result shows that the film has an infrared transmittance switching efficiency of 77% in the metal-insulator transition. The color changing properties indicate that the film color reversibly changes from khaki to yellow-green as the temperature changes. The relationship between ΔE* and the temperature presents a hysteresis loop, which is in accordance with the infrared optical switching properties. The maximum of ΔE* during the film metal-insulator transition is 11.31.