Synthesis and characterization of V1-xMo(x)O2 thermochromic coatings with reduced transition temperatures

In this study Mo-doped VO2 thin films have successfully been grown on SiO2-coated float glass by reactive DC magnetron sputtering. Structural analyses, carried out at room temperature, revealed single-phase monoclinic VO2 with preferred crystal orientation in the (002) direction, regardless the Mo doping concentration. The surface morphology of the films revealed elongated grains dispersed randomly with decreasing sizes for higher Mo doping concentrations. The measured roughness parameters showed an opposite tendency, i.e., increased for higher Mo doping contents. The optical analyses showed films with maximum optical transparencies in the visible range from 35 to 45% and decreased IR modulation capacity from 36 to 25% with increasing Mo content from 3 to 11%. The Mo dopant concentration in the film was found to have a linear influence on the phase transition temperatures, showing a decrease of about 3 degrees C per at% of Mo. Phase transition temperatures as low as 32 degrees C were obtained.