Enhancement of Blue Emission via Upconversion in Solid-State Synthesized Hexagonal NaYF4:Ln3+

2008 ◽  
Vol 368-372 ◽  
pp. 398-401 ◽  
Author(s):  
You Na Wu ◽  
Chang Hua Cheng ◽  
Zhao Xian Xiong
Keyword(s):  
Solid State ◽  
Continuous Wave ◽  
Hexagonal Phase ◽  
Blue Emission ◽  
Upconversion Emission ◽  
Continuous Wave Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Diffraction Patterns

Hexagonal NaYF4:Ln3+ (Ln3+=Yb3+ and Tm3+) was prepared via solid-state synthesis route. The synthesized powders were identified with X-ray diffraction patterns. Hexagonal phase was obtained by heating the powders at 550°C in reducing atmosphere, and the ions of Yb3+ and Tm3+ were completely incorporated into the lattice of hexagonal NaYF4 in the doping concentration range. Microstructure of the phosphor was observed by scanning electron microscopy (SEM). Intense blue (1G4→3H6, 1D2→3F4) and weak red (1G4→3F4) upconversion emission of Tm3+ ions with the energy transferred from Yb3+ ions were observed in the phosphor excited with a 980nm continuous wave laser diode. The intensity of blue emission was effectively enhanced by suitable doping of Tm3+ and Yb3+ ions, and strongest blue emission was obtained with the concentration of 0.2mol% Tm3+ and 40mol% Yb3+ doped.

Effect of Al2O3 Xerogel on the Microstructure and the Properties of Laser Cladding Coating of Fe-Based Alloy

2010 ◽  
Vol 434-435 ◽  
pp. 743-746
Author(s):  
Shi Hai Zhao ◽  
Xiu Ming Jiang ◽  
Xu Guo Huai ◽  
Xiao Wei Fan
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Continuous Wave ◽  
Continuous Wave Laser ◽  
Dispersion Strengthening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al2o3 Particles ◽  
Molten Liquid ◽  
Steel Substrates

Laser cladding Fe-based alloy coatings with 0, 3, 6, 9, 12 and 15% Al2O3 xerogel on 45 steel substrates were prepared by 5kWCO2 continuous wave laser. The effect of the content of Al2O3 xerogel on the microstructure, microhardness and wear resistance of the coatings was investigated by scan electron microscope, X-ray diffraction. The results show that the microstructure and properties were different when the content of Al2O3 xerogel changed. The addition of Al2O3 xerogel can enhance the fluidity of molten liquid and refine the microstructure. Adding adequate amount of Al2O3 xerogel to Fe-based alloy can improve the hardness and the wear resistance due to the nano-Al2O3 particles on surfaces and the dispersion strengthening and hardening of nano- Al2O3 particles.

Powder X-Ray Data for Synthetic Anhydrous Sodium Zirconium Silicates

1987 ◽  
Vol 2 (3) ◽  
pp. 176-179 ◽  
Author(s):  
G. Wilson ◽  
F. P. Glasser
Keyword(s):  
Solid State ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
The Other ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Sodium Zirconium ◽  
Diffraction Patterns

AbstractA systematic survey of phase formation in the Na2O-ZrO2-SiO2 system has revealed inconsistencies in the number and identity of ternary phases, and of their X-ray powder data. The phases Na2ZrSiO5, Na4Zr2Si3O12, Na2ZrSi2O7 and Na2ZrSi4O11 were prepared by solid-state reaction and their experimental X-ray diffraction patterns measured. Calculated X-ray diffraction patterns were generated by computer, using published crystallographic data, and critically compared with the experimentally observed values. The unit-cell constants were redefined to a greater accuracy than the presently accepted values published in the Powder Diffraction File. Only Na4Zr2Si3O12 produced an X-ray diffraction pattern which agreed with that previously published; those from the other phases were significantly different in both the intensities and positions of the reflections. Data for synthetic Na2ZrSi4O11 identical to the mineral vlasovite are reported.

Structure analysis of CaTi1−xSnxO3 (x = 0.0–1.0) solid solutions

2014 ◽  
Vol 29 (3) ◽  
pp. 254-259 ◽  
Author(s):  
Naoki Takani ◽  
Hisanori Yamane
Keyword(s):  
Solid State ◽  
Solid Solutions ◽  
Solid State Reaction ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns ◽  
Perovskite Type ◽  
Perovskite Type Structure

CaTi1−xSnxO3 (x = 0.0–1.0) solid solutions were prepared by solid-state reaction at 1450 °C. Rietveld refinement of their powder X-ray diffraction patterns revealed that all the solid solutions crystallized in orthorhombic cells with the perovskite-type structure, the space group Pbnm. The refined unit-cell parameters linearly increased with nominal tin contents x.

Thermoelectric and Structural Properties of Bi1-xTe1+x Thin Films on CdTe(111)

1998 ◽  
Vol 545 ◽  
Author(s):  
Yunki Kim ◽  
Sunglae Cho ◽  
Antonio DiVenere ◽  
George K. Wong ◽  
Jerry R. Meyer ◽  
...  
Keyword(s):  
Thin Films ◽  
Structural Properties ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Power Generator ◽  
X Ray ◽  
Compositional Changes ◽  
Diffraction Patterns ◽  
P Type

AbstractThin films of the hexagonal phase of Bi1-xTe1+x have been grown on CdTe(111) substrates using molecular beam epitaxy (MBE). Analysis of X-ray diffraction patterns (θ-2θ scans and rocking curves) of the films shows that their crystallinity depends upon the compositional deviation from stoichiometric BiTe. Measurements of the temperature-dependent thermoelectric power (TEP) of the films reveals that compositional changes cause the TEP to vary from electron dominant (n-type) to hole dominant (p-type), implying their possible application as a thermoelectric cooler or power generator. Measurements of the temperature-dependent resistivity of the films were conducted, and the analysis shows semimetallic behavior. These results demonstrate that Bi1-xTe1+xis an appropriate model system to study the dependencies of thermoelectric and structural properties on binary composition.

Effect of Excitation Wavelength on the Blue Emitting Sr2MgSi2O7 Phosphor

2015 ◽  
Vol 1087 ◽  
pp. 360-364 ◽  
Author(s):  
C.H. Chang ◽  
Swee Yong Pung ◽  
M.N. Ahmad Fauzi ◽  
Shah Rizal Kasim
Keyword(s):  
Electron Microscope ◽  
Solid State ◽  
Scanning Electron Microscope ◽  
Blue Emission ◽  
Excitation Wavelength ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Long Afterglow ◽  
Crystal Phases ◽  
Scanning Electron

Long afterglow blue emission silicate (SMS) phosphor doped with Eu2+ and Ce3+ was synthesized via traditional solid-state reaction in the weak reducing atmosphere. X-ray diffractometer (XRD), field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray (EDX) spectroscope were employed to characterize its crystal phases, surface morphology and elements composition. The photoluminescence (PL) properties were characterized by PL Spectrophotometer. It was found that the excitation wavelength played a significant role in photoluminescence emission intensity.

scholarly journals Structural, Optical, and Photocatalytic Properties of ZnSe Nanoparticles Influenced by the Milling Time

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1125
Author(s):  
Bui Thi Thu Hien ◽  
Vu Thanh Mai ◽  
Pham Thi Thuy ◽  
Vu Xuan Hoa ◽  
Tran Thi Kim Chi
Keyword(s):  
Raman Spectra ◽  
Milling Time ◽  
Blue Emission ◽  
Near Band Edge ◽  
X Ray Diffraction ◽  
Znse Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Average Size

ZnSe nanoparticles (NPs) were prepared by combining both hydrothermal and mechanical milling methods. Transmission electron microscopy images show that fabricated ZnSe NPs with a sphere-like shape have an average size (d) in the range of 20–100 nm, affected by changing the milling time from 10 to 60 min. All the samples crystalize in zincblende-type structure without impurities, as confirmed by analyzing X-ray diffraction patterns, Raman spectra, and energy-dispersive X-ray spectroscopy. Carefully checking Raman spectra, we have observed the broadening and redshift of vibration modes as decreasing NP size, which are ascribed to extra appearance of disorder and defects. The photoluminescence study has found a blue emission at 462 nm attributed to the excitonic near-band edge and a broad defect-related emission around 520–555 nm. Increasing milling time leads to the decrease in the exciton-emission intensity, while the defect-related emissions increase gradually. Interestingly, as decreasing d, we have observed an improved photodegradation of Rhodamine B under UV irradiation, proving application potentials of ZnSe NPs in photocatalytic activity.

Zur Kenntnis von Hydridhalogeniden MHX der Seltenen Erden Eu, Yb und Sm (X = Cl, Br, I) / A Study on Hydride Halide Compounds MHX of the Rare Earths Eu,Yb, and Sm (X = Cl,Br,I)

1982 ◽  
Vol 37 (5) ◽  
pp. 574-578 ◽  
Author(s):  
H. P. Beck ◽  
A. Limmer
Keyword(s):  
Solid State ◽  
Crystal Chemistry ◽  
Rare Earths ◽  
Alkaline Earth ◽  
Lattice Parameters ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

New hydride halide compounds MHX (M = Eu, Yb, Sm; X = Cl, Br, I) of divalent rare earths have been prepared by solid-state reactions. Lattice parameters and X-ray diffraction patterns are presented for these compounds. All compounds are isostructural with tetragonal PbFCl. Refined lattice parameters of alkaline earth hydride halides are given. The crystal chemistry of MHX and MFX is compared and the geometric variations in the structure of these compounds are interpreted on the basis of changes in covalency

An N-pattern display for an SSD X-ray diffractometer

1982 ◽  
Vol 15 (2) ◽  
pp. 232-235
Author(s):  
S. Hosoya ◽  
T. Sakamaki ◽  
Y. Nakano ◽  
T. Fukamachi
Keyword(s):  
Solid State ◽  
Electron Diffraction ◽  
Small Computer ◽  
X Ray Diffraction ◽  
Solid State Detector ◽  
X Ray ◽  
New Type ◽  
Diffraction Patterns ◽  
Pattern Display ◽  
State Detector

The present paper describes a new type of display for X-ray diffraction patterns which corresponds to the N pattern well known in electron diffraction. This has been realized by an ω-circle SSD (solid-state detector) diffractometer equipped with a CRT display all operated by a small computer. The merits are described of its possible applications.

Microstructure Properties of Bi0.5Na0.5TiO3-BaZrO3 Piezoelectric Ceramics

2012 ◽  
Vol 151 ◽  
pp. 310-313
Author(s):  
Jenn Sen Lin ◽  
Teng Chin Yu ◽  
Cheng Hsing Hsu ◽  
Ci Jie Huang ◽  
His Wen Yang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid State Route ◽  
Diffraction Patterns ◽  
Conventional Solid State Route ◽  
Scanning Electron

The microstructure properties of the perovskite Bi0.5Na0.5TiO3-BaZrO3 ceramics were prepared with the conventional solid-state route have been investigated. The resultant microstructure properties were analyzed based upon the densification, the X-ray diffraction patterns and scanning electron microscopy. The correlation between the microstructures and the sintering temperature was also examined.

scholarly journals Structure properties and dielectric relaxation of Ca0.1Na0.9Ti0.1Nb0.9O3 ceramic

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25358-25367 ◽  
Author(s):  
Hanen Ghoudi ◽  
Souad Chkoundali ◽  
Zeineb Raddaoui ◽  
Abdelhedi Aydi
Keyword(s):  
Solid State ◽  
Dielectric Relaxation ◽  
Rietveld Refinement ◽  
Solid State Reaction ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Diffraction Patterns ◽  
Structure Properties

In this paper, the synthesis of Ca0.1Na0.9Ti0.1Nb0.9O3 (CNTN) ceramic by a solid-state reaction is reported. The results of Rietveld refinement of X-ray diffraction patterns at room temperature showed a pure tetragonal perovskite (P4mm space group).

Sign in / Sign up

Export Citation Format

Share Document