Infrared Switching of Self-Heating VO2/ITO Films for Smart Window

Abstract

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 (Tc) 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.