A. Dussan; Heiddy P. Quiroz
Abstract
In this work, we fabricated samples of titanium dioxide nanotube arrays via electrochemical anodization by using titanium foils as anode and cathode. A solution of water, ethyleneglycol, and ammonium fluoride (NH4F) at room temperature was used for the samples synthesis process. Different times and anodizing ...
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In this work, we fabricated samples of titanium dioxide nanotube arrays via electrochemical anodization by using titanium foils as anode and cathode. A solution of water, ethyleneglycol, and ammonium fluoride (NH4F) at room temperature was used for the samples synthesis process. Different times and anodizing voltages were used during reaction. From X-ray diffraction (XRD) and micro-diffraction (mXRD) measurements, rutile and anatase phases were identified as function of deposition parameters. The Ti3O5 phase was observed by deconvolution of Debye-Scherrer rings of the microdiffraction spectra. Annealing processes were performed for all samples in the range between 273 and 723 K, without changes in the material’s morphological properties, while the crystalline structure was affected. Nanotube diameters varying between 30 and 42 nm were observed from SEM micrographs, when NH4F concentration was changed from 0.25 to 0.50 wt%. An alternating anodizing voltage generates the formation of nanotubes evenly spaced on the surface with nodes in bamboo-type form, while a smooth form for nanotubes was observed with constant applied voltage. From stereoscopic 3D micrographs, a reconstruction of the topographic surface of the TiO2 nanotubes was conducted. A correlation between synthesis parameters and morphological properties is presented.
Thoudam Nando Singhi; Thongam Gomti Devi; Shougaijam Dorendrajit Singh
Abstract
Eu 3+ doped TiO2 (0.2-1at. %) is synthesized successfully by non-aqueous sol-gel technique at low temperature. They are characterized structurally and optically with the used of X-ray diffraction (XRD), UV-visible spectrophotometer, Photoluminescence (PL), microscopy (SEM) and Transmission electron microscopy ...
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Eu 3+ doped TiO2 (0.2-1at. %) is synthesized successfully by non-aqueous sol-gel technique at low temperature. They are characterized structurally and optically with the used of X-ray diffraction (XRD), UV-visible spectrophotometer, Photoluminescence (PL), microscopy (SEM) and Transmission electron microscopy (TEM). The anatine toretile phase transition is observed at 750 o C and lattice distortion ratios are reduced whereas crystallites sizes are found to increase with increases of temperature. The emission spectrum under excitation at the 7 F0→ 5 L6 (393nm) transition of the Eu 3+ ion shows broad emission bands arising from the 5 DJ (J=0, 1) levels and with the emission decays lifetime varying between 0.243 and 0.375ms for samples prepared at different temperatures. The Judd-Ofelt intensity parameters W2 are found in the range 6.57 - 17.14 x10 -20 cm 2 at different concentrations and temperatures. Quantum yield of all the samples are more than 80% at different temperature. The average decay lifetime decreases with the increase of Eu 3+ concentration.