Strong photoluminescence (PL) is observed in nanostructured crystalline tungsten oxide thin
films that are prepared by thermal evaporation. Two kinds of films are investigated—one
made of nanoparticles and another of nanowires. At room temperature, strong PL emissions
at ultraviolet-visible and blue regions are found in both of the films. Compared with the
complete absence of emission of bulk phase tungsten oxide powder under the same
excitation conditions, our results clearly demonstrate the quantum-confinement-effect …