The Upconversion Luminescence Properties of Er3+/Tm3+, Yb3+-Codoped Cubic BaLiF3

2016 ◽  
Vol 16 (4) ◽  
pp. 3715-3719 ◽  
Author(s):  
Qinping Qiang ◽  
Linna Guo ◽  
Lili Han ◽  
Yuhua Wang
Keyword(s):  
Energy Levels ◽  
Upconversion Luminescence ◽  
Luminescence Properties ◽  
Excitation Wavelength ◽  
Power Dependence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Upconversion Emissions ◽  
Surfactant Assisted ◽  
Scanning Electron

Cubic BaLiF3 samples were prepared using a facile surfactant-assisted hydrothermal-microemulsion method. The samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The upconversion luminescence (UCL) properties of the Er3+/Tm3+, Yb3+-codoped BaLiF3 samples were measured under a 980 nm excitation wavelength. Moreover, the effects of varying the concentration of Li+ ions on the luminescence properties of Er3+, Yb3+ codoped BaLiF3 were also investigated. The Tm3+, Yb3+ codoped BaLiF3 samples displayed multicolor emissions. This behavior can be explained by the pump power dependence of the upconversion emissions and the energy levels diagram.

Blue Upconversion Luminescence Properties of La2(WO4)3:Yb3+/Tm3+Phosphor

2011 ◽  
Vol 399-401 ◽  
pp. 1020-1025
Author(s):  
Jin Sheng Liao ◽  
Hang Ying You ◽  
Qing Xia Wu ◽  
He Rui Wen ◽  
Jing Lin Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Hydrothermal Process ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Pumping ◽  
Upconversion Mechanism ◽  
Upconversion Emissions ◽  
Scanning Electron

Monoclinic La2(WO4)3 nanophosphors codoped with Tm3+ and Yb3+ ions were synthesized via hydrothermal process followed by heat treatment. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize as-prepared samples. The dependences of Yb3+/ concentration and laser pumping power on the upconversion emissions were extensively investigated. The results show that upconversion luminescence increases with the Yb3+/ concentration and gets its peak at 30 %. The upconversion mechanism and process in the Yb3+/Tm3+ codoped La2(WO4)3 phosphors were analysed.

Preparation, Characterization and Spectroscopy of Eu3+ in Gd2O3 Nanorods

2008 ◽  
Vol 8 (3) ◽  
pp. 1398-1403 ◽  
Author(s):  
Liqin Liu ◽  
En Ma ◽  
Renfu Li ◽  
Xueyuan Chen
Keyword(s):  
Electron Microscopy ◽  
Fluorescence Spectra ◽  
Filling Factor ◽  
Energy Levels ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Eu3+:Gd2O3 nanorods were prepared by a hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy were used to characterize the resulting samples. Emission and excitation spectra were studied using xenon excited spectroscopic experiments at 10 K. Energy transfer from Gd3+ to Eu3+, from the band gap of the host to Eu3+, and from Eu3+ (S6) to Eu3+ (C2) was observed. The energy levels of Eu3+ at the C2 site of cubic Gd2O3 were experimentally determined according to the fluorescence spectra at 10 K, and fit well with the theoretical values. The standard deviation for the optimal fit was 12.9 cm−1. The fluorescent lifetime of 5D0 (2.3 ms at 295 K) was unusually longer than that of the bulk counterparts (0.94 ms), indicating a small filling factor (0.55) for the nanorod volume. However the lifetime of 5D1 was much shorter than that of the bulk counterparts, 65 μs at 10 K, 37 μs at 295 K.

Concentration-Dominated Temperature-Dependence of Upconversion Luminescence in Gd6WO12 Nanophosphor Co-Doped with Er3+ and Yb3+

2016 ◽  
Vol 16 (4) ◽  
pp. 3534-3541
Author(s):  
Yanqiu Zhang ◽  
Baojiu Chen ◽  
Xiangping Li ◽  
Jiashi Sun ◽  
Jinsu Zhang ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Thermal Quenching ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Two Photon ◽  
Microscopic Morphology ◽  
Co Precipitation ◽  
Co Doped ◽  
Scanning Electron

Nanosized Gd6WO12 phosphors containing various Er3+ concentrations and fixed Yb3+ concentration were synthesized by a co-precipitation method. The crystal structure and microscopic morphology of the obtained nanophosphors were characterized by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). Two-photon processes for both the green and red upconversion (UC) emissions were confirmed by analyzing the dependence of UC intensities on 980 nm laser working current. UC emission intensity changing with temperature displays different trends for the samples with different Er3+ concentrations. The experimental results indicated that thermal quenching behavior of UC luminescence could not be simply explained by crossover mechanism. The enhancement for green UC emission in the sample with higher Er3+ concentration was discussed. Finally, the Er3+ concentration dependence of UC luminescence was experimentally observed, and its mechanisms were analyzed.

Structural and Photoluminescence Characteristics of ZnTiO3:Pb2+ Nanofibers Produced by Electrospinning

2013 ◽  
Vol 562-565 ◽  
pp. 908-913 ◽  
Author(s):  
Rong Li Sang ◽  
Ying Chen ◽  
Qing Jun Zhang ◽  
Lin Wang
Keyword(s):  
Sol Gel ◽  
Excitation Wavelength ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Charge Transfer Transitions ◽  
Ultrathin Fibers ◽  
Ft Ir ◽  
Gel Processing ◽  
Scanning Electron

By sol-gel processing and electrospinning technique, ultrathin fibers of PVP/ ZnTiO3:Pb2+ composites were synthesized. After calcined of the fibers at 600°C, the spinel ZnTiO3:Pb2+ nanofibers, with a diameter of 100-200nm, were successfully obtained. The scanning electron microscopy (SEM), fourier transform infrared (FT-IR), X-ray diffraction (XRD) and photoluminescence (PL) were employed in the study. The results displayed that the morphology and crystalline phase of the fibers were greatly affecteded by the calcination temperature. The PL spectra of the samples measured at different excitation wavelength reveal a novel luminescent phenomenon in blue and green region, which can be attributed to the Pb2+-related charge-transfer transitions in ZnTiO3 nanofibers.

scholarly journals Hydrothermal Synthesis and Tunable Multicolor Upconversion Emission of Cubic Phase Y2O3Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Haibo Wang ◽  
Chao Qian ◽  
Zhigao Yi ◽  
Ling Rao ◽  
Hongrong Liu ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Upconversion Emission ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Light Yellow ◽  
Color Displays ◽  
Transmission Electron ◽  
Subsequent Calcination ◽  
Upconversion Emissions

Highly crystalline body-centered cubic structure Y2O3with lanthanide (Ln) codopants (Ln = Yb3+/Er3+and Yb3+/Ho3+) has been synthesized via a moderate hydrothermal method in combination with a subsequent calcination. The structure and morphology of Y(OH)3precursors and Y2O3nanoparticles were characterized by X-ray diffraction and transmission electron microscopy. The results reveal that the Y2O3nanoparticles possess cubic phase and form the quasispherical structure. The upconversion luminescence properties of Y2O3nanoparticles doped with different Ln3+(Yb3+/ Er3+and Yb3+/ Ho3+) ions were well investigated under the 980 nm excitation. The results show that the Yb3+/Er3+and Yb3+/Ho3+codoped Y2O3nanoparticles exhibit strong red and light yellow upconversion emissions, respectively. It is expected that these Y2O3nanoparticles with tunable multicolor output and intense red upconversion emission may have potential application in color displays and biolabels.

Optical and thermal stimulated luminescence in carbon nanotubes

2011 ◽  
Vol 225 (4) ◽  
pp. 145-147
Author(s):  
Jung-Chuan Fan ◽  
Huang-Huei Sung ◽  
Chun-Rong Lin
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Energy Levels ◽  
Infrared Emission ◽  
Major Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Simple Alternative ◽  
Luminescence Measurement ◽  
Scanning Electron

The semiconductivity of carbon nanotubes has been investigated by the luminescence measurement. The nanotubes were characterized by scanning electron microscopy and X-ray diffraction. Carbon nanotubes can luminesce under laser irradiation. Using the photoluminescence measurements the emission spectrum is very wide near the infrared emission range, with a major peak at 1.3 eV. According to the temperature dependence of the photoluminescence and the thermal photoluminescence experiments, the luminescence of carbon nanotubes comes from the center of the energy trap of a defect. In view of this result, it is suggested that the technique of thermal stimulated luminescence provides a simple alternative method to obtain the energy levels in carbon nanotubes systems.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

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