Facile Solution-Grown Mo-Doped Vanadium Dioxide Thermochromic Films with Decreased Phase Transition Temperature and Narrowed Hysteresis Loop Width

Abstract

Molybdenum (Mo) doped vanadium dioxide (VO2) (V1-xMoxO2) thermochromic thin films with different Mo concentrations on borosilicate glasses were successfully synthesized via a facile and economic solution-based deposition method. The influences of substitutional doping with Mo dopants on the crystal structure and film morphology of VO2 were evaluated. All of the films were confirmed to be pure monoclinic crystalline phase of VO2 and no molybdenum oxides formed, suggesting the formation of a homogeneously dispersed solid-solution. The particle sizes and root-mean-square (RMS) roughness level obviously decreased upon Mo doping. V1-xMoxO2 films exhibited low metal-semiconductor transition (MST) temperature (Tc) and retained the excellent switching property at near-infrared region simultaneously. The rate of change of Tc with Mo doping reached as high as ~10°C/at.%. The reduced Tc may be attributed to the disruption of homo-polar V4+-V4+ bonding after the incorporation of Mo atoms in VO2 octahedron configuration. V1-xMoxO2 thin films exhibited narrower hysteresis loop width compared to undoped VO2, which show the promise for promoting practical implementation of VO2-based thermochromic fenestration.