Infrared switching of self-heating vo₂/ito films for smart window

The unique metal to insulator transition (MIT) of vanadium dioxide (VO₂) makes it receiving extensive attention in the application of smart window. As for VO₂-based smart window, the critical transition temperature (T_c) is required to be reduced to near room temperature for practical applications. In this paper, we fabricated VO₂ films on ITO glass by hydrothermal method and applied voltage to ITO, therefore, the joule heat generated by ITO triggered the complete MIT of VO₂ at room temperature in very short time ~3 s with applied voltage of 12 V. The VO₂ film on ITO substrate shows obviously widened hysteresis behavior in the reversible transition process with a thermal hysteresis width of ~33 °C. The widened hysteresis loop makes it possible to stabilize the rutile phase (R) of VO₂ at room temperature via applying a low holding voltage of 6 V. The proposed VO₂/ITO film exhibits promising application in active smart window, and possesses advantages of simple structure, easy-fabricated and low-cost.