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We have studied making and characterization of gasochromic thin films that are used as gas sensors. Gasochromic films consist of an electronchromic layer and a catalyst layer. Addition of palladium to the surface , increased the sensitivity and decreased the working temperature. The used electrochromic layer was tungsten oxide. WO3 films were fabricated by (PLD) method. The substrates were slide glasses. Structure, morphology and composite of tungsten oxide and optical property of films depend on condition of deposition. The pressure of oxygen gas in chamber and temperature of substrate are two factors that can affect in deposition. We can make layers with different morphology by variation... 

Physical and chemical properties of tungsten oxide thin films change reversibly while exposure to hydrogen gas. This property is called gasochromic. To enhance optical properties of such films, nanostructured, amorphous and porous thin films of (WO3)1-x(MeO)x (MeO= TiO2, MoO3, NiO; x=0.09, 0.17, 0.23, 0.29, 0.33) were fabricated by Pulsed Laser Deposition. Molar percentage of Me/W (Me= Ti, Mo and Ni) was changed in films with respect to targets; for Ti and Ni always a reduction, but for Mo an enhancement for low percentages was observed. The reason is the existence of thermal ablation mechanism during deposition, in the other word is different vapor pressure effect. An increment in x for... 

In the present thesis the fabrication of various tungsten oxide nanostructures (films and colloidal nanoparticles) with coverage of catalyst on their surfaces has been investigated which show gasochromic properties. Tungsten oxide films and nanoparticles were synthesized by pulsed laser abalation technique in vacuum and liquid environment, respectively. To activate the synthesized films and nanoparticles against hydrogen gas, the catalyst nanoparticles (Pd or Pt) were deposited onto their surface through hydrogen reduction of metal salt and electroless methods, respectively. The products were characterized by XPS, UV-Vis., AFM and DLS techniques. The prepared samples show significant color...