Jakrapong Kaewkhao

Structural and Magnetic Properties of Glass Doped with Iron Oxide

Glasses based on borosilicate system were prepared by melt-quenching method in the composition range of (mol%) 20Na2O : 1.0Al2O3 : 13B2O3 : 6.3CaO : 0.2Sb2O3 : 4.5BaO : (55−X)SiO2 : xFe2O3 (where x = 0, 5, 10, 15, 20 and 25) and the structural, optical and magnetic properties were investigated. The result showed that the density and molar volume of glasses increased with increasing of Fe2O3 concentration. This might be due to an increase of Fe2O3 concentration at the expense of SiO2 caused the opened glass network structure. Fe2O3 also affected the change of B2O3 structure detected by FTIR technique. The magnetic measurement revealed that the glass sample exhibited a ferrimagnetic behavior when doping with 25 % mol Fe2O3.

Measurement of Mass Attenuation Coefficients of Blue Sapphire at Different Photon Energy by Compton Scattering Technique

The mass attenuation coefficients of blue sapphire were measured at the different energy of γ-rays using the Compton scattering technique. There are in good agreement of scattered gamma rays energies between theoretical value and experimental value, reflecting the validation of Compton scattering system setup. The results show that, the experimental values of mass attenuation coefficient are in good agreement with the theoretical values. The mass attenuation coefficients increase with the decrease in gamma rays energies. This may be attributed to the higher photon interaction probability of blue sapphire at lower energy. This result is a first report of mass attenuation coefficient of blue sapphire at different gamma rays energies.

Physical, Structural and Luminescence Properties of ZnO-Bi2O3-B2O3 Glass System

The ZnO-Bi2O3-B2O3 (ZBB) glasses with different concentrations of Bi2O3 have been prepared by a conventional melt quenching technique and investigated the effect of Bi2O3 on the physical, structural and luminescence properties. The density and hardness of glasses are also measured and found to increase with increase of Bi2O3 concentration. The IR studies indicate that these glasses are made up of [BiO3], [BO3], [BO4] and [B basic structural units. From optical spectra, the cut-off wavelengths were shifted from 423 nm to 447 nm as the content of Bi2O3 increases from 15 to 30 mol%. The photoluminescence spectra exhibit characteristic peaks at 602 nm corresponding to 3P11S0 transitions of Bi3+. The decay time for 3P1 level of Bi3+ increases with increase of Bi2O3 concentration.

Fabrication and Characterization of Antibacterial Ag-TiO2 Thin Films Prepared by DC Magnetron Co-Sputtering Technique

In this study, silver-doped titanium dioxide (Ag-TiO2) thin films were prepared co-sputtering technique in order to promote photo-induced antibacterial applications. The high-purity Ag (99.995%) and Ti (99.995%) were simultaneously co-sputtering on BK7 glass and silicon (100) wafers substrate. The structure, morphology, surface roughness and optical properties were characterized by grazing-incidence X-ray diffraction (GIXRD), field-emission scanning electron microscopy (FE-SEM) and UV-Vis spectrophotometer, respectively. The results showed that the as-deposited Ag-TiO2 thin films had high transparency in the visible range. The antibacterial activity was studied in the presence and in the absence of UV irradiation against Escherichia coli as a model for Gram-negative bacteria. The results indicated that, in comparison to conventional TiO2 films, the Ag-TiO2 thin films exhibited excellent antibacterial properties under the UV illumination.

Properties of CoO doped in Glasses Prepared from Rice Hush Fly Ash in Thailand

In this work, properties of glass from local rice husk ash (RHA) in Thailand have been investigated. RHA was sintered in different temperature. Compositions and phases of RHA were analyzed by energy dispersive x-ray fluorescence spectrometer (EDXRF) and X-ray diffractometer (XRD). The glasses were melt from RHA in formula 20 Na2O : 1.0 Al2O3 : 13 B2O3 : 6.3 CaO : 0.2 Sb2O3 : 4.5 BaO : 55SiO2 (using RHA as a SiO2 source) The density values of all RHA glasses are comparable and larger than glass from pure SiO2 under same glass formula and preparing condition. These results are corresponding with refractive index values. The RHA glasses showing colorless with absorption edge in ultraviolet region were obtained. The dark blue color glasses were melted from RHA with different CoO concentration. From this part, not found to be the relation of density and refractive index of glass with CoO concentration in glass matrix. From absorption spectra, the absorption peak were appeared around 600 nm, and peak intensity are increased, with increase CoO, correspond to 4A2(4F) → 4T1(4P) state of Co2+ in tetrahedral symmetry.

Functionalization of Au Nanoparticles on ZnO Nanorods through Low-Temperature Synthesis

Hybrid nanomaterials exhibit multi-functionalities, which is synergy or enhanced physical and optical properties over their single components with promising potentials for various applications in dye-sensitized solar cell and photocatalytic materials. In this present research, the Au nanoparticles were prepared at HAuCl4 concentration of 0.5 mM on ZnO nanorod templates and silicon wafer substrate by hydrothermal reaction process. The prepared samples were investigated the crystal structure, chemical composition and morphologies by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM), respectively. The XRD results shown that ZnO was preferred orientation along the c-axis (002). The FE-SEM images indicated to the difference of size-Au NPs decorated on ZnO nanorods and silicon wafer. The relationship between the surface area and the size of Au NPs of the prepared samples was investigated and possible growing mechanism of Au NPs on ZnO nanorods templates will be discussed.

Spectroscopic Properties and Judd-Ofelt Analysis of Dy3+ in Lithium Lanthanum Borate Glass for Laser Medium Application

Dysprosium doped lithium lanthanum borate glasses (LiLaB:Dy3+) were prepared by the melt quenching technique, varying the Dy2O3 doped concentration from 0.00 to 1.50 mol%. The absorption spectra showed that LiLaB:Dy3+ glass absorbed photon in visible light and near infrared region. From the excitation of 388 nm, this glass emitted the photon with 483, 575, 664 and 753 nm wavelength. The intensity of emission increased with increasing of Dy2O3 concentration until 1.0 mol%, after that it decreased. The Judd-Ofelt (J-O) analysis was applied to 1.0 mol% doped glass to investigate the J-O parameter, radiative transition possibility and stimulated emission cross section. These values were interpreted to the ability of laser gain medium.

Visible Luminescence of Pr3+ in Bismuth Borate Glasses

Visible luminescence of Pr3+ ions in bismuth borate glasses doped with difference concentration of Pr2O3 have been studies. The glasses of composition 30Bi2O3 : (70-x)B2O3 : xPr2O3 (where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%) were prepared by the melt quenching technique. The spectral properties were investigated using the absorption and emission measurement. These glasses have shown emission and excitation bands in visible region. The emission band of Pr3+ doped glass centered at 600 nm (1D23H4), 642 nm (3P03F2) and 704 nm (3P03F3) have been observed with 469 nm (3H43P1) excitation wavelength. The excitation band revealed centered at 447, 469 and 482 nm corresponding to the 3H43P2, 3P1 and 3P0 transitions, respectively.

Physical, Optical and Luminescence Properties of Er3+-Doped Bismuth Borosilicate Glasses

Er3+-doped bismuth borosilicate glasses (Bi2O3+B2O3+SiO2+Er2O3) glasses doped with different Er2O3 concentrations (0, 0.50, 1.00, 1.50, 2.00, 2.50 mol%) have been prepared by melt quenching technique and their physical, optical and luminescence properties have been studied. The density of glasses showed the highest value at 4.7358 g/cm3 with 1.00 mol% of Er2O3. The optical absorption spectra of glasses were observed seven bands at 488, 523, 543, 654, 801, 975 and 1529 nm which assigned to the transitions 4I15/2→4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2 and 4I13/2, respectively. The emission spectra of glasses were also investigated and discussed in term of energy level of Er3+ ion in glass matrices.

Preparation and Properties of Er3+ Doped with Bi2O3-BaO-B2O3 Glass

Er2O3-doped Bi2O3BaOB2O3 glasses were prepared by the conventional melt-quenching method. The glasses of the composition (in mol%) (40-x)B2O3:40Bi2O3:20BaO:xEr2O3 (where x = 0.00, 0.50, 1.00, 1.50, 2.00 and 2.50) were prepared by the melt quenching method. The density and molar volume measurements were carried out at room temperature. Absorption spectra were investigated in the UVVISNIR region from 300 to1800 nm. The upconversion photoluminescence spectra were observed in the visible region.