Comparison between the optical and surface properties of TiO 2 and Ag/TiO 2 thin films prepared by sol-gel process
- PDF / 321,877 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 96 Downloads / 167 Views
Comparison between the optical and surface properties of TiO2 and Ag/TiO2 thin films prepared by sol-gel process Marcelo M. Viana and Nelcy D. S. Mohallem* Laboratory of Nanostructured Materials, Chemistry Department, UFMG, Belo Horizonte-MG, Brazil *[email protected] ABSTRACT Colloidal precursor solutions, obtained from a mixture of titanium isopropoxide, isopropyl alcohol and silver nitrate, were used to fabricate amorphous TiO2 and Ag/TiO2 thin films by sol-gel process. The films were deposited on borosilicate substrates, which were heated at 400 °C for 30 minutes and cooled rapidly to the formation of amorphous coatings. The films were investigated by X-ray diffraction, scanning electron microscopy, atomic force microscopy and UV-vis spectroscopy. The thickness, roughness, refraction index, and particle size of the TiO2 and Ag/TiO2 films were determined and compared. Finally, hydrophobic-hydrophilic property was evaluated to the thin films produced. INTRODUCTION Systems containing TiO2 nanoparticles have attracted interest in several research areas by providing numerous applications in different industries, linked to improving the quality of life. As example we can mention applications in pharmaceuticals, pigments, food and cosmetics, as well as others related to the semiconducting properties of TiO2, with emphasis on the photocatalytic applications, mainly involving the photodegradation of organic pollutants [1-4]. Systems containing Ag nanoparticles also have been investigated mainly due to their potential applications in modern electronic devices [5], medicine [6], optical sensors [7] and biology [8]. The preparation of composites containing both the materials favors the coupling of their structures, leading to additional or enhanced properties. These phenomena can be verified in their photocatalytic properties [9] and in the surface plasmon resonance (SPR) formed by the Ag nanoparticles distribution on the TiO2 surface [10] that can modify the optical, hydrophobichydrophilic and bactericidal properties of the material surface. In this work, optical, structural and morphological properties of TiO2 and Ag/TiO2 thin films prepared by sol-gel process were evaluated using X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and UV-visible spectroscopy. Moreover, TiO2 and Ag/TiO2 thin films were tested for their hydrophobic- hydrophilic properties.
69
EXPERIMENT TiO2 thin films have been prepared by sol-gel process from an alcoholic solution containing tetraisopropyl orthotitanate (Merck) and isopropyl alcohol (Merck) and the Ag/TiO2 films by using the same precursors and silver nitrate (Aldrich). The atomic ratio Ag:Ti was 1:6. UV- C irradiation (λ=254 nm) were used to promote the Ag+ reduction in solution. The precursor solutions were maintained under agitation at room temperature for 1 hour and the films were dipcoated onto clean glass substrates with withdrawal speed of 8 mm/sec, dried in air for 30 min and thermally treated for 15 min at 400 °C followed by fast cooling. Th
Data Loading...
