CORRELATION BETWEEN PALLADUM NANOPARTICLE GROWTH ANDSURFACE CHARACTERISTICS OF TUNGSTEN OXDE THN FILMS OFPD/WO FOR GASOCHROMIC APPLICATIONS

Nowadays, gasochromic Pd/WO3 coatings as optically switchable materials during H2 absorption have become more interesting due to their novel applications in smart windows and gas sensors. To active a tungsten oxide layer against the hydrogen, a thin layer of Pd or Pt is deposited on its surface. In this study, we report the development of a simple method to deposit Pd nanoparticles upon the sol-gel derived WO/glass films. WO nanostructured films were first prepared by sol-gel (spin coating) method on glass substrates and then they were annealed at different temperatures from 100 to 400 °C. Pd nanoparticles were deposited from a Pd* containing solution by hydrogen reduction. The structural and morphological properties of the samples were investigation by the Fourier Transform Infrared (FTIR), Atomic force Microscope (AFM) and contact angle measurements. FTIR revealed the variation of chemical bonds at the layers. AFM images revealed that by increasing the annealing temperature, nanocrystalline particles of tungsten oxide are formed over the surface. Hydrophobic behavior of samples found to be dependent on annealing temperature. We found a correlation between palladium deposition qualities, gas sensing and surface characteristics of tungsten oxide substrate.

Keywords:

: tungsten oxide , palladium nanoparticles , gas sensor , sol-gel , surface