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

Molybdenum (Mo) doped vanadium dioxide (VO 2 ) (V 1- x Mo x O 2 ) 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 VO 2 were evaluated. All of the films were confirmed to be pure monoclinic crystalline phase of VO 2 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. V 1- x Mo x O 2 films exhibited low metal-semiconductor transition (MST) temperature (T c ) and retained the excellent switching property at near-infrared region simultaneously. The rate of change of T c with Mo doping reached as high as ~10°C/at.%. The reduced T c may be attributed to the disruption of homo-polar V 4+ -V 4+ bonding after the incorporation of Mo atoms in VO 2 octahedron configuration. V 1- x Mo x O 2 thin films exhibited narrower hysteresis loop width compared to undoped VO 2 , which show the promise for promoting practical implementation of VO 2 -based thermochromic fenestration.