Optical properties and electrochromic response of nanostructured molybdenum trioxide films

We report on the electrochromic response of as-deposited and annealed nanostructured molybdenum trioxide films prepared with the glancing angle deposition (GLAD) technique. Morphology of the as-deposited films, obtained with an atomic force microscope (AFM), showed a typical grain size of 10 to 50 nm diameter. After annealing, the AFM images clearly showed the dominant presence of a layered structure, characteristic of the orthorhombic (a) phase of molybdenum trioxide, with typical grain dimensions of a few micrometers. The annealed samples showed pronounced coloration in the visible and near-infrared regions of the electromagnetic spectrum, while the as-deposited samples showed significant coloration only in the visible region.