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    Surface Modification of Silica Particles Taken from Waste Glass by Surfactant Treatment for Light Scattering Application
    (2022-03-01)
    Boonyarattanakalin, Kanokthip
    ;
    Mekprasart, Wanichaya
    ;
    Manivong, Aphisit
    ;
    Wechprasit, Tirapat
    ;
    Chongsri, Krisana
    This work aims to modify the surface of silicon dioxide particles for high dispersion property in the host matrix. Silicon dioxide powders were obtained from wasted material as broken beaker glass and reduced its particle size by high energy milling process operating at 500 rpm for 30 min. These particles can be proposed as an effective light scatterer and applied in the transparent light planar waveguide for the improvement of light emission performance. However, the main problem of using milled silica powder is the poor dispersion in the polymer matrix. Therefore, the surface modification method is a key role to resolve this obstacle by using polymer surfactant agents as polyvinyl alcohol, polyethylene glycol, and sodium hexametaphosphate. The proper polymer surfactant in the surface modification on silica powders has been revealed. The particle size of each condition was analyzed by a particle analyzer. Modified silica particle size with polymer surfactants trended to decrease lower than 1 µm owing to good dispersion of the particles by polymer chain and interaction between silica and surfactant surface. Chemical functional groups on modified silica powders were investigated by Fourier transform-infrared (FT-IR) spectroscopy. FTIR spectra shown that main chemical components of all samples were composed of silica and borate chemical bonding. Meanwhile, the O-H stretching vibration appeared in the spectra was a key role for particle size and good dispersion of modified surface silica particles in the solution. Moreover, light scattering property and transmission of modified silica with polymer surfactants in dispersion solution were detected by luminance meter and UV-Vis spectrometer to confirm its possibility for application in light scattering material. The best polymer surface for milled silica surface modification in this work was obtained from polyvinyl alcohol, which proved that the adjustment of surface charge and physical properties on the silica surface.
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    Omnidirectional anti-reflection properties of vertically align SiO2 nanorod films prepared by electron beam evaporation with glancing angle deposition
    (2018-01-01)
    Prachachet, R.
    ;
    Samransuksamer, B.
    ;
    Horprathum, M.
    ;
    Eiamchai, P.
    ;
    Limwichean, S.
    Omnidirectional anti-reflection coating nanostructure film have attracted enormous attention for the developments of the optical coating, lenses, light emitting diode, display and photovoltaic. However, fabricated of the omnidirectional antireflection nanostructure film on glass substrate in large area was a challenge topic. In the past two decades, the invention of glancing angle deposition technique as a growth of well-controlled two and three-dimensional morphologies has gained significant attention because of it is simple, fast, cost-effective and high mass production capability. In this present work, the omnidirectional anti-reflection nanostructure coating namely silicon dioxide (SiO<inf>2</inf>) nanorods has been investigated for optimized high transparent layer at all light incident angle. The SiO<inf>2</inf> nanorod films of an optimally low refractive index have been fabricated by electron beam evaporation with the glancing angle deposition technique. The morphological of the prepared sampled were characterized by field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HRTEM). The optical transmission and omnidirectional property of the SiO<inf>2</inf> nanorod films were investigated by UV-Vis-NIR spectrophotometer. The measurement were performed at normal incident angle and a full spectral range of 200 - 2000 nm. The angle dependent transmission measure were investigated by rotating the specimen, with incidence angle defined relative to the surface normal of the prepared samples. The morphological characterization results showed that when the glancing angle deposition technique was applied, the vertically align SiO<inf>2</inf> nanorods with partially isolated columnar structure can be constructed due to the enhanced shadowing and limited addtom diffusion effect. The average transmission of the vertically align SiO<inf>2</inf> nanorods were higher than the glass substrate reference sample over the visible wavelength range at all incident angle due to the transition in the refractive index profile from air to the nanostructure layer that improved the anti-reflection characteristics.
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    A comparative study on omnidirectional anti-reflection SiO2 nanostructure films coating by glancing angle deposition
    (2018-01-01)
    Prachachet, R.
    ;
    Samransuksamer, B.
    ;
    Horprathum, M.
    ;
    Eiamchai, P.
    ;
    Limwichean, S.
    Fabricated omnidirectional anti-reflection nanostructure films as a one of the promising alternative solar cell applications have attracted enormous scientific and industrial research benefits to their broadband, effective over a wide range of incident angles, lithography-free and high-throughput process. Recently, the nanostructure SiO<inf>2</inf> film was the most inclusive study on anti-reflection with omnidirectional and broadband characteristics. In this work, the three-dimensional silicon dioxide (SiO<inf>2</inf>) nanostructured thin film with different morphologies including vertical align, slant, spiral and thin films were fabricated by electron beam evaporation with glancing angle deposition (GLAD) on the glass slide and silicon wafer substrate. The morphological of the prepared samples were characterized by field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HRTEM). The transmission, omnidirectional and birefringence property of the nanostructure SiO<inf>2</inf> films were investigated by UV-Vis-NIR spectrophotometer and variable angle spectroscopic ellipsometer (VASE). The spectrophotometer measurement was performed at normal incident angle and a full spectral range of 200 - 2000 nm. The angle dependent transmission measurements were investigated by rotating the specimen, with incidence angle defined relative to the surface normal of the prepared samples. This study demonstrates that the obtained SiO2 nanostructure film coated on glass slide substrate exhibits a higher transmission was 93% at normal incident angle. In addition, transmission measurement in visible wavelength and wide incident angles -80 to 80 were increased in comparison with the SiO2 thin film and glass slide substrate due to the transition in the refractive index profile from air to the nanostructure layer that improve the antireflection characteristics. The results clearly showed the enhanced omnidirectional and broadband characteristic of the three dimensional SiO2 nanostructure film coating.