KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Access type: UnknownSubject: search.filters.subject.Sol-gel method

Search Results

Now showing 1 - 5 of 5
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Effect of surfactant concentration on the formation of Fe2O3@SiO2 NIR-reflective red pigments
    (2021-05-01)
    Soranakom, Piya
    ;
    Vittayakorn, Naratip
    ;
    Rakkwamsuk, Pattana
    ;
    Supothina, Sitthisuntorn
    ;
    Seeharaj, Panpailin
    High NIR-reflective red pigments were developed by encapsulating Fe<inf>2</inf>O<inf>3</inf> particles in a transparent SiO<inf>2</inf> shell layer to form Fe<inf>2</inf>O<inf>3</inf>@SiO<inf>2</inf> core-shell structures. The pigments were prepared by a sol-gel process and the effect of CTAB surfactant concentration on structural formation and optical properties was investigated. The reaction between CTAB and silica species was found to increase the yield of SiO<inf>2</inf> formation, which had a major role to control the SiO<inf>2</inf> shell thickness by ranging from 8 to 62 nm when varying CTAB concentration from 0 to 2 mM. After encapsulation, Fe<inf>2</inf>O<inf>3</inf>@SiO<inf>2</inf> pigments still had the red-brown hue of hematite and the NIR reflectivity improved to 62.7 %–65.3%, or twice that of the uncoated Fe<inf>2</inf>O<inf>3</inf>. The pigments prepared using the highest CTAB concertation changed from the original Fe<inf>2</inf>O<inf>3</inf> color (CIE Lab color space coordinates) by only ΔE 8.2% due to the formation of second phase SiO<inf>2</inf> microspheres formed from excess CTAB micelles. The NIR-reflective red Fe<inf>2</inf>O<inf>3</inf>@SiO<inf>2</inf> pigments showed good chemical stability and light resistance, thus they were suitable for use as cool pigments for coating applications.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Effect of titanium dopant on physical and optical properties Of Wo 3 thin films prepared by sol-gel method
    (2019-01-01)
    Kahattha, Chokchai
    ;
    Noonuruk, Russameeruk
    ;
    Pecharapa, Wisanu
    In this present work, the influence of incorporated Ti dopants on the physical and optical properties of WO <inf>3</inf> sol-gel derived thin films are investigated and represented. Ti-doped WO <inf>3</inf> thin films with different Ti doping contents (5 wt%, 10 wt%, and 20 wt%) are fabricated on F-doped tin oxide substrates using the spin coating technique. Tungsten powders and titanium butoxide are used as starting sources of the W and Ti ions, respectively. After the coating process, as-deposited films are annealed at 500°C for 2 h in ambient air. The effects of the dopant on the crystal structure, surface morphologies, chemical bonding, and optical properties of the films are investigated by the X-ray diffraction technique (XRD), scanning electron microscopy, Fourier transform infrared (FTIR), and ultraviolet-visible spectrophotometry. The XRD results indicate the monoclinic structure of the prepared films with a significant alteration in the crystalline size when the film was incorporated with the Ti dopant. The FTIR results reveal the deterioration in the W and O bonding as the film is doped with the Ti dopant. The optical band gaps of the films exhibit a significant blue shift with increasing the Ti doping content. The optical density change and cyclic voltammetry results indicate that the performance of WO <inf>3</inf> film applied as a smart window or energy storage can be enhanced by doping with Ti ions.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Role of Sb-dopant on physical and optical properties of ZnO thin film deposited by sol-gel-based coating method
    (2019-01-01)
    Sinornate, Wuttichai
    ;
    Mimura, Hidenori
    ;
    Pecharapa, Wisanu
    Sb-doped ZnO films were prepared by sol-gel spin coating technique on glass substrate. The sol-gel was prepared from zinc acetate dihydrate as zinc precursor and diethanolamine as sol stabilizer. Antimony (III) acetate was selected as the precursor of Sb. The doping concentration was varied from 0 to 10 mol%. The films were prepared by spin coating technique following by annealing at 500°C for 2 h in ambient air. The XRD exhibits ZnO hexagonal wurtzite without impurity phase. Their XRD peaks show deterioration in crystallinity that is in accordance with FESEM and TEM images showing decreasing in particle size with increasing doping content. The XPS confirm the existence of Sb<sup>3+</sup> that could substitute Zn<sup>2+</sup> on the zinc site or zinc vacancy. The photoluminescence results exhibit blue-shift with increasing Sb doping concentration. The transmittance spectra show high transmittance above 90% in visible region.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Preparation and characterization of cu-doped ZnO sol-gel derived optical thin films
    (2013-10-29)
    Chongsri, Krisana
    ;
    Aunpang, Siriwattana
    ;
    Techitdheera, Wicharn
    ;
    Pecharapa, Wisanu
    In this work, we report the preparation of Cu-doped ZnO thin films by sol-gel method based on zinc acetate dihydrate (CH<inf>3</inf>COO)<inf>2</inf>Zn·2H<inf>2</inf>O, Copper acetate dihydrate Cu<inf>3</inf>(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O) and diethanolamine (HN(CH<inf>2</inf>OH)<inf>2</inf>, DEA). The precursor solution was prepared at various Cu composition ranging from 2-20 wt%. All films were spin-coated on borosilicate substrates for several coating repetition followed by annealing process at 550 °C for 4 h in an ambient air. The structural properties of the films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD results indicate the domination of hexagonal wurtzite structure of ZnO with noticeable alternation in the XRD peak intensity upon Cu doping content. SEM results revealed the grain size shape and surface morphologies of as-prepared samples. Crucial optical properties of as-prepared films were scrutinized from their UV-Vis transmission spectra. The films are highly transparent in the visible region with more than 90% transparency within 380 nm to 800 nm. Their corresponding band gaps indicate significant red shift with increasing Cu doping content. Overall results suggest that Cu additive play a vital role on relevant optical properties of ZnO that can be adjusted to meet the requirement for practical optoelectronics applications. © (2013) Trans Tech Publications, Switzerland.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    N-doped MgZnO alloy thin film prepared by sol-gel method
    (2011-06-30)
    Chongsri, K.
    ;
    Boonruang, S.
    ;
    Techitdheera, W.
    ;
    Pecharapa, W.
    In this work, nitrogen-doped MgZnO thin films were deposited on glass substrate by spin-coating technique and thermal annealing treatment. The X-ray diffraction (XRD), scanning electron microscope (SEM) and optical transmission measurement were carried out to investigate the effect of growth temperature and nitrogen doping on the physical and optical properties of the films. XRD and SEM results revealed that the crystallinity and preferred c-axis orientation was enhanced with increasing annealing temperature and certain concentration of N-doping. In addition, the films incorporated with nitrogen doping exhibit significant blue shift in optical band gap and improvement in its transparency. © 2011 Elsevier B.V. All rights reserved.