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Author: search.filters.author.Kongteweelert, Samart

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    Optical properties of Cu0.95Pt0.05Fe0.97Sn0.03O2 for p-type transparent conducting oxide materials
    (2013-08-30)
    Ruttanapun, Chesta
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    Kahatta, Sagulthai
    ;
    Boonchom, Banjong
    ;
    Vittayakorn, Naratip
    ;
    Thongkam, Montree
    The Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> sample has been synthesized by a solid-state reaction to investigate optical properties of materials of transparent conducting oxide. Crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature (300 to 860 K), while the XPS and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient reveals the samples displays the p-type conducting. The XPS spectra show the Sn2+ state stabling in this compound. The optical direct gap is 3.45 eV as a visible-transparent material. These results support that the Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> oxide compounds, of which the Cu<sup>1+</sup> and Fe<sup>3+</sup> sites are substituted by the Pt<sup>1+</sup> and Sn<sup>2+</sup> ions respectively, are p-type transparent conducting oxide materials. © (2013) Trans Tech Publications, Switzerland.
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    Facile, alternative synthesis of spherical-like ca(H2PO4)2•H2O nanoparticle by aqueous-methanol media
    (2013-08-30)
    Kongteweelert, Samart
    ;
    Ruttanapun, Chesta
    ;
    Thongkam, Montree
    ;
    Chaiyasith, Pachernchaipat
    ;
    Woramongkonchai, Somsak
    Spherical-like calcium dihydrogenphosphate monohydrate (Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>•H<inf>2</inf>O) nanostructure was successfully prepared by the mixing of calcium carbonate and phosphoric in aqueous-methanol media at ambient temperature for 30 min. Three thermal decomposition step and higher stability at over 800°C of the prepared sample are different from the earlier works. Spherical-like Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>•H<inf>2</inf>O nanostructure with diameter < 100 nm confirmed by SEM may be important for potential applications. This method of synthesis by aqueous-methanol media is a fast and simple method and it is expected to be applicable for the synthesis of other nanocrystalline calcium phosphates. © (2013) Trans Tech Publications, Switzerland.
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    A simple route to synthesize ferromagnetic binary calcium iron pyrophosphate CaFeP2O2 using aqueous-acetone media
    (2013-08-30)
    Chaiyasith, Pachernchaipat
    ;
    Ruttanapun, Chesta
    ;
    Thongkam, Montree
    ;
    Kongteweelert, Samart
    ;
    Woramongkonchai, Somsak
    A binary calcium iron pyrophosphate CaFeP<inf>2</inf>O<inf>7</inf> was synthesized by solid state route using the mixing of calcium carbonate, iron metal and phosphoric acid in aqueous-acetone media at 600°C. The XRD datum indicates the formation of CaFeP<inf>2</inf>O<inf>7</inf> phase without the presence of any phase impurities. FTIR result indicates the presence of the P<inf>2</inf>O<inf>7</inf> <sup>4-</sup> anion in the structure. Sheet-like microparticle of CaFeP<inf>2</inf>O<inf>7</inf> was revealed by SEM. Room temperature magnetization result showed ferromagnetic behavior of the synthesized CaFeP<inf>2</inf>O<inf>7</inf>, with saturation-specific magnetization value of 11.067 emu g<sup>-1</sup> at 10kOe. The magnetic feature of the synthesized CaFeP<inf>2</inf>O<inf>7</inf> in this work compared with M<inf>2</inf>P<inf>2</inf>O<inf>7</inf> (M = Ca and Fe), its isotypic (CaMP2O7 (M= Mn and Co) and CFeP<inf>2</inf>O<inf>7</inf> (C= Co and Cu) reported in our previous works is important properties for specific applications. © (2013) Trans Tech Publications, Switzerland.
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    A new synthesis of BaHPO4 precipitated by BaCO3-H4PO4-NaOH system at room temperature
    (2013-08-30)
    Boonchom, Banjong
    ;
    Ruttanapun, Chesta
    ;
    Thongkam, Montree
    ;
    Chaiyasith, Pachernchaipat
    ;
    Woramongkonchai, Somsak
    Barium hydrogenphosphate, BaHPO<inf>4</inf> was synthesized for the first time through simple and rapid method using BaCO<inf>3</inf>-H<inf>3</inf>PO<inf>4</inf>-NaOH, pH =9.0 at room temperature for 30 min. The studied BaHPO<inf>4</inf> decomposed in a single well-defined stage via deprotonated hydrogenphosphate reactions, revealed by TG/DTG and DSC techniques. The calculated wavenumbers based on DSC peak were comparable with FTIR results, which support the breaking bonds of P-OH (HPO<inf>4</inf><sup>2-</sup>) in the deprotonated hydrogenphosphate reactions. The thermodynamic functions (ΔH*, ΔG*, and ΔS*) for the deprotonated hydrogenphosphate reactions calculated from DSC data indicate that the deprotonated HPO<inf>4</inf><sup>2-</sup> reaction occur a lower-energy pathway and spontaneous process. The FTIR, XRD and SEM data of the studied BaHPO<inf>4</inf> and its decomposed product Ba<inf>4</inf>P<inf>2</inf>O<inf>7</inf> are also reported. © (2013) Trans Tech Publications, Switzerland.