Journal ArticleDOI
Chromium Environment within Cr-Doped BaAl2O4: Correlation of X-ray Diffraction and X-ray Absorption Spectroscopy Investigations.
TLDR
X-ray diffraction patterns indicated that samples were nanocrystalline with a hexagonal crystal structure, space group P63, and extended X-ray absorption fine structure suggested an unusual tetrahedral coordination of Cr(3+) ions within the BaAl2O4 host phase.Abstract:
Powder BaAl2O4 samples doped with 0 and 1.76 atom % Cr in relation to Al were hydrothermally prepared. Both samples were characterized by X-ray diffraction and synchrotron based X-ray absorption spectroscopy at the Cr K- and the Ba L3-edge. Diffraction patterns indicated that samples were nanocrystalline with a hexagonal crystal structure, space group P63. Chromium doping of barium aluminate caused an increase of the unit-cell volume and diffraction line broadening. The doped sample contained a small amount of an impurity phase, namely, BaCrO4. Analyzed Cr K-edge X-ray absorption near edge structure for the doped sample showed the presence of chromium in 6+ and 3+ oxidation states: Cr(6+) was characteristic for chromium in the impurity phase BaCrO4, while Cr(3+) participated in the formation of the doped phase BaAl2O4:Cr. Extended X-ray absorption fine structure suggested an unusual tetrahedral coordination of Cr(3+) ions within the BaAl2O4 host phase. The structure of samples was refined by the Rietveld method, simultaneously with the analysis of diffraction line broadening. Rietveld structure refinement showed that in doping the Cr(3+) ions likely substituted for Al(3+) ions on Al1 tetrahedral sites of barium aluminate crystal lattice. Crystallite sizes in the samples decreased with chromium doping, from 32 nm for pure BaAl2O4 to 24 nm for Cr-doped BaAl2O4. The dopant Cr(3+) cations acted as defects in the barium aluminate structure that increased lattice strain from 0.02% for pure BaAl2O4 to 0.14% for doped BaAl2O4 and disturbed the crystallites to grow.read more
Citations
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Ultra-Broadband Phosphors Converted Near-Infrared Light Emitting Diode with Efficient Radiant Power for Spectroscopy Applications
Veeramani Rajendran,Veeramani Rajendran,Tadeusz Lesniewski,Sebastian Mahlik,Marek Grinberg,Grzegorz Leniec,Slawomir Maksymilian Kaczmarek,Wei Kong Pang,Yan Shen Lin,Kuang Mao Lu,Chih-Min Lin,Ho Chang,Shu Fen Hu,Ru-Shi Liu,Ru-Shi Liu +14 more
TL;DR: Narrowing the size of near-infrared (NIR) spectrometers has gained substantial interest among researchers in both scientific and nonscientific communities due to the inherent usage in the nondestru...
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Disentangling site occupancy, cation regulation, and oxidation state regulation of the broadband near infrared emission in a chromium-doped SrGa4O7 phosphor
Jun'an Lai,Jianbei Qiu,Qi Wang,Dacheng Zhou,Zhangwen Long,Yong Yang,Songhan Hu,Xizheng Li,Jiacheng Pi,Jing Wang +9 more
TL;DR: In this paper, a particular gallium SrGa4O7 (SGO) was employed as a host for chromium doping and the characteristic broadband NIR emission of Cr3+ ions in octahedral sites centered in the range of 650 to 1200 nm with a full width at half maximum (FWHM) of 140 nm and an internal quantum efficiency of more than 46% was observed.
Journal ArticleDOI
Recent developments in lanthanide-doped alkaline earth aluminate phosphors with enhanced and long-persistent luminescence
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Journal ArticleDOI
Composites of BaAl2O4:Eu2+,Dy3+/organic dye encapsulated in mesoporous silica as multicolor long persistent phosphors based on radiative energy transfer
TL;DR: A multicolor BaAl2O4:Eu2+,Dy3+/dye encapsulated in mesoporous SiO2 composite long persistent phosphor is developed based on a radiative energy transfer process as discussed by the authors.
Journal ArticleDOI
Environment of the Eu3+ Ion within Nanocrystalline Eu-Doped BaAl2O4: Correlation of X-ray Diffraction, Mössbauer Spectroscopy, X-ray Absorption Spectroscopy, and Photoluminescence Investigations
Biserka Gržeta,Dirk Lützenkirchen-Hecht,Martina Vrankić,Sanja Bosnar,Ankica Šarić,Masashi Takahashi,Dimitar Petrov,Marijan Bišćan +7 more
TL;DR: Powder samples of pure BaAl2O4 and doped with 4.9 atom % Eu in relation to Ba were prepared by a hydrothermal route, and the observed emission spectrum indicated that Eu3+ ions occupied the Ba site with lower symmetry in the doped sample.
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