scholarly journals Microbe-Assisted Synthesis and Luminescence Properties of Monodispersed Tb3+-Doped ZnS Nanocrystals

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Zhanguo Liang ◽  
Jun Mu ◽  
Lei Han ◽  
Hongquan Yu
Keyword(s):  
Emission Spectra ◽  
Peak Position ◽  
Ion Concentration ◽  
Luminescence Properties ◽  
Main Peak ◽  
X Ray ◽  
Sulfate Reducing ◽  
Potential Applications ◽  
Sphalerite Phase ◽  
High Luminescence Intensity

Tb3+-doped zinc sulfide (ZnS:Tb3+) nanocrystals were synthesized by spray precipitation with sulfate-reducing bacterial (SRB) culture at room temperature. The morphology of the SRB and ZnS:Tb3+nanocrystals was examined by scanning electron microscopy, and the ZnS:Tb3+nanocrystals were characterized by X-ray diffractometry and photoluminescence (PL) spectroscopy. The PL mechanism of ZnS:Tb3+nanocrystals was further analyzed, and the effects of Tb3+ion concentration on the luminescence properties of ZnS:Tb3+nanocrystals were studied. ZnS:Tb3+nanocrystals showed a sphalerite phase, and the prepared ZnS:Tb3+nanocrystals had high luminescence intensity under excitation at 369 nm. The main peak position of the absorption spectra positively blueshifted with increasing concentrations of Tb3+dopant. Based on the strength of the peak of the excitation and emission spectra, we inferred that the optimum concentration of the Tb3+dopant is 5 mol%. Four main emission peaks were obtained under excitation at 369 nm:489 nm (5D4→7F6), 545 nm (5D4→7F5), 594 nm (5D4→7F4), and 625 nm (5D4→7F3). Our findings suggest that nanocrystals have potential applications in photoelectronic devices and biomarkers.

SPECTRUM ANALYSIS TAKING ACCOUNT OF THE TAIL, ESCAPE FUNCTIONS AND SUB-LINES (SAPIX version 4)

2000 ◽  
Vol 10 (03n04) ◽  
pp. 101-114 ◽  
Author(s):  
K. SERA ◽  
S. FUTATSUGAWA
Keyword(s):  
Response Function ◽  
Spectrum Analysis ◽  
Peak Position ◽  
Main Peak ◽  
Small Shift ◽  
Escape Peak ◽  
X Ray ◽  
Peak Separation ◽  
Small Peak ◽  
Tail Function

A new x-ray-spectrum-analysis program, which is capable of fitting with response functions including a tail function, an escape peak and sub-lines, has been developed. In this code, the tail function is expressed by combination of two or three Gaussian functions. A tail function, an escape and sub- or satellite-lines are regarded as functions belonging to the main peak and are included in it. A small shift of peak position depending on measuring conditions can be easily corrected in the program. As a result of fitting to practical spectra with the response function thus prepared, it becomes possible to draw a smooth background over a wide x-ray-energy range and to analyze a whole spectrum simultaneously. Thus, accuracy and reproducibility of a spectrum analysis are much improved. By means of this code, correct values of peak yield of Co - K α, which overlaps with the tail of Fe - K β and is quite difficult to be accurately separated by fitting with Gaussians, have been obtained. Furthermore, accuracy of peak separation of a small peak, which overlaps with the escape peak belonging to a huge peak, has been improved. Accuracy of quantitative analysis for high-Z elements by means of Kβ yields has also been improved by using the response function including sub-lines, and it became possible to accurately separate small Kα lines from Kβ lines of the other elements.

Luminescence Properties of ZnO:Eu3+ Red Emitting Phosphor Prepared by Precipitation Method

2013 ◽  
Vol 690-693 ◽  
pp. 594-597
Author(s):  
Lin Yan Jia ◽  
Zhong Bao Shao ◽  
Jun Feng Han
Keyword(s):  
Doping Concentration ◽  
Emission Spectra ◽  
Electric Dipole Transition ◽  
Dipole Transition ◽  
Luminescence Properties ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Matrix Lattice ◽  
Red Emitting Phosphor

Zinc oxide doped with Eu3+ ions red emitting phosphors were prepared by precipitation method, and its luminescence properties were investigated. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectra. The ZnO:Eu3+ phosphors were obtained at 600°C by calcining precipitation precursor. These phosphors can be effectively excited at 465nm. In emission spectra, the strongest peak at 616nm correlating to red emission is due to the electric dipole transition 5D07F2 of Eu3+ ions. Eu3+ions replaced Zn2+ ions and occupied the non-centrosymmetric sites in the ZnO matrix lattice. The phosphor particles with narrow distribution range are approximately 100-200nm in size. The luminescence properties of ZnO:Eu3+ phosphor with 8 mol% doping concentration of Eu3+ is optimal.

scholarly journals A Spectroscopic and structural study of FeCoSb alloy

2019 ◽  
Vol 17 (41) ◽  
pp. 67-74
Author(s):  
Saba J. Kadhem
Keyword(s):  
Emission Spectra ◽  
Spherical Shape ◽  
Peak Position ◽  
Stark Broadening ◽  
X Ray Diffraction ◽  
Plasma Parameters ◽  
Visible Absorption ◽  
Boltzmann Plot ◽  
Iron Cobalt ◽  
X Ray

Fe, Co and Sb nanopowders were fruitfully prepared by electrical wire explosion method in Double distilled and de-ionized water (DDDW) media. The formation of iron, cobalt and antimony (FeCoSb) alloy nanopowder was monitored by X-ray diffraction. The x-ray diffraction pattern indicates that there are iron, cobalt and antimony peaks. Optical properties of this alloy nanoparticles were characterized by UV-Visible absorption spectra. The absorption peak position is shifted to the lower wavelengths when the current increases. That means the mean size of the nanoparticles controlled by changing the magnitude of the current. The surface morphological analysis is carried out by employing Scanning Electron Microscope (SEM). Particles with varies size were observed also from the images the some particles have uneven shapes with agglomerate and the other have spherical shape. The exploding FeCoSb alloy wire plasma parameters is study by optical emission spectroscopy. The emission spectra of the plasma have been recorded and analyzed. The plasma electron temperature (Te), was determined by Boltzmann plot, and the electron density (ne), by Stark broadening for wire with diameter 0.3 mm and current of 75A in distilled water.

Synthesis, Characterization and Luminescence Properties of Rod-Like LaPO4:Eu3+ Nanostructures

2016 ◽  
Vol 16 (4) ◽  
pp. 4012-4015 ◽  
Author(s):  
Li Peng ◽  
Liu Yun ◽  
Shi Xiaolei ◽  
Guo Yaxin ◽  
Zhu Gangqiang
Keyword(s):  
Large Scale ◽  
Room Temperature ◽  
Emission Spectra ◽  
Luminescence Properties ◽  
X Ray ◽  
Sem And Tem ◽  
Effects Of Ph ◽  
Composition Structure ◽  
20 Nm ◽  
Fluorescence Spectrometer

Large-scale, rod-like nanostructures of LaPO4:Eu3+ phosphors were synthesized using a simple hydrothermal method. The phase composition, structure and morphology of the final products were characterized by XRD, FE-SEM and TEM. Highly crystalline material was obtained as confirmed by X-ray powder diffraction measurements. The FE-SEM and TEM observations indicate that the obtained LaPO4:Eu3+ nanorods have a diameter of about 10–20 nm, and a length of about 100–600 nm. Meanwhile, the excitation and emission spectra of the products at room temperature were measured using a fluorescence spectrometer. The effects of pH and Eu3+-doping on the morphology and luminescence properties of the as-prepared powders were investigated. The photoluminescence (PL) spectra show that the emission intensity of the LaPO4:Eu3+ phosphors improved with increases in concentrations of Eu3+ from 3 mol% to 14 mol%, and then decreased for higher concentrations.

Microcalorimeter EDS Measurements of Chemical Shifts in Fe Compounds

1998 ◽  
Vol 4 (S2) ◽  
pp. 196-197 ◽  
Author(s):  
D. A. Wollman ◽  
Dale E. Newbury ◽  
G. C. Hilton ◽  
K. D. Irwin ◽  
L. L. Dulcie ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Energy Dispersive Spectrometer ◽  
Emission Spectra ◽  
High Energy ◽  
Peak Position ◽  
Binding Energies ◽  
High Energy Resolution ◽  
X Ray ◽  
Valence Electrons ◽  
Electron Binding Energies

We report measurements of chemical shifts in the Fe-L x-ray lines of different Fe compounds from xray emission spectra acquired using a microcalorimeter energy dispersive spectrometer (EDS). The observed changes in peak position and relative intensity of the Fe-L x-ray lines are in agreement with measurements obtained using a wavelength dispersive spectrometer (WDS), demonstrating the usefulness of microcalorimeter EDS for high-energy-resolution x-ray microanalysis.Chemical shifts result from changes in electron binding energies with the chemical environment of atoms. In x-ray spectra, chemical shifts lead to changes in x-ray peak positions, relative peak intensities, and peak shapes. These chemical bonding effects can be significant (with x-ray peak shifts on the order of 1 eV), particularly for x-ray lines resulting from transitions involving valence electrons of light elements such as B and C.

Effect of Nd3+ on the Properties of Lithium Niobium Borate Crystal and Glass

2017 ◽  
Vol 268 ◽  
pp. 210-216
Author(s):  
Wan Hairul Anuar Kamaruddin ◽  
Md Supar Rohani ◽  
Md Rahim Sahar ◽  
Hong Liu
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Emission Spectra ◽  
Ion Concentration ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Thermal Analyzer ◽  
Quenched Glass ◽  
Polaron Radius

1 mol% of neodymium-doped lithium niobium borate (NdLNB) glass and crystal have been produced by using melt-quenching and Czochralski technique, respectively. The synthesis, growth and characterizations of the samples were reported. X-ray diffraction (XRD), Differential thermal analyzer (DTA), Ultraviolet-Visible-Near-Infrared (UV-Vis-NIR) and Photoluminescence (PL) spectroscopic characterizations were made to examine the influence of Nd3+ on the physical, structural and optical properties of the samples. Various physical properties such as density, molar volume, ion concentration, polaron radius, inter-nuclear distance and field strength were calculated. The as-quenched glass was amorphous whereas crystal was crystalline as established via XRD studies. UV-Vis-NIR spectra exhibited eight prominent bands centered at 353, 475, 524, 583, 681, 745, 803, 875 nm corresponding to the transitions from the ground state to 4D3/2, 2G9/2, 4G7/2, 4G5/2, 4F9/2, 4F7/2, 4F5/2, 4F3/2 excited states, respectively. Moreover, the emission spectra at 355 nm excitation displayed several peaks that contributed to the transition of(4F3/2→4I9/2) and (4F3/2→4I11/2), respectively. Fluorescence lifetime was recorded at 53.69 µs for the glass whereas the crystal was recorded at 43.62 µs. It was found that Nd3+ ions affected the physical, structural and optical properties of the glass and crystal samples.

Synthesis and Luminescence Properties of Ba3Y1-xEuxB3O9 (0.05≤x≤0.35) under UV Excitation

2014 ◽  
Vol 906 ◽  
pp. 60-65 ◽  
Author(s):  
Xiao Xia Li
Keyword(s):  
Particle Size ◽  
Single Phase ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Hexagonal Structure ◽  
Luminescence Properties ◽  
Excitation Energies ◽  
Excitation Spectra ◽  
X Ray ◽  
Uv Excitation

Single phase of Ba3Y1-xEuxB3O9 (0.05 ≤ x≤ 0.35)samples was prepared by the solid state reaction. The crystal structure, the surface, the particle size and luminescence properties were characterized by X-ray diffractometer, scanning electron microscopy and spectrophotometer. The results showed that the obtained samples with the particle size from 0.3 to 1.5 um were hexagonal structure. Monitored by 592 nm emission, the excitation spectra of Ba3Y1-xEuxB3O9were dominated by the charge transfer band of O2-→Eu3+ peaking at about 259 nm until x= 0.15; the transition from 7F0 to 5L6 level of Eu3+ at about 395 nm was maximum after x> 0.15. The strongest emission peak due to the 5D0→7F1transition of Eu3+ was all located at about 592 nm in the emission spectra of Ba3Y1-xEuxB3O9, and the maximum emission was obtained at x= 0.15 and 0.3 under 254 and 395 nm excitation, respectively. The excitationprocess under the two excitation energies was analyzed. It indicated that only the centrosymmetric lattices could be excited under 254 nm excitation; both the centrosymmetric and noncentrosymmetric positions could be excited by 395 nm, accordingly, the ratio of the red emission (5D0→7F2) to the orange one (5D0→7F1) increased, leading to a better chromaticity of the phosphors.

Preparation, structural characterization, and luminescence properties of Eu3+-doped nanocrystalline ZrO2

2005 ◽  
Vol 20 (10) ◽  
pp. 2780-2791 ◽  
Author(s):  
A. Speghini ◽  
M. Bettinelli ◽  
P. Riello ◽  
S. Bucella ◽  
A. Benedetti
Keyword(s):  
Sol Gel ◽  
Emission Spectra ◽  
Luminescence Properties ◽  
X Ray ◽  
Preparation Conditions ◽  
X Ray Scattering ◽  
Decay Times ◽  
Zirconia Nanopowders ◽  
Hydrolysis Of ◽  
Ray Scattering

Eu3+-doped zirconia nanopowders were prepared by the sol-gel technique using two different methods, based on the hydrolysis of zirconium n-propoxide, producing tetragonal and monoclinic zirconia under different preparation conditions. A detailed microstructure characterization was performed through wide angle x-ray scattering, small angle x-ray scattering, trasmission electron microscopy, and nitrogen physisorption measurements. The possible influence of the zirconia crystalline phases and particle sizes on the luminescence properties of the lanthanide ion was investigated. A detailed analysis of the emission spectra of the samples suggested that the dopant Eu3+ ions replace the Zr4+ ions in the zirconia crystal lattice. Moreover, samples prepared by the two different methods were characterized by different decay times of the Eu3+ ion luminescence.

Hydrothermal Synthesis and Luminescent Properties of Spherical LaPO4:Ln3+ (Ln3+= Eu3+, Dy3+, Ce3+, Tb3+)

2015 ◽  
Vol 1120-1121 ◽  
pp. 396-400 ◽  
Author(s):  
Jie Dai ◽  
Guo Chao Li ◽  
Meng Lv ◽  
Rui Sen Zhou ◽  
Xia Li
Keyword(s):  
Emission Spectra ◽  
Luminescent Properties ◽  
Flat Panel Displays ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Strong Light ◽  
X Ray ◽  
Ultraviolet Excitation ◽  
Structure Morphology ◽  
Potential Applications

Uniform LaPO4 and LaPO4:Ln3+ (Ln3+= Eu3+, Dy3+, Ce3+, Tb3+) microspheres have been selectively synthesized via a hydrothermal route, without using any catalyst, or template. X-ray diffraction, SEM, TEM, and photoluminescence spectroscopy were used to characterize the phase structure, morphology, and luminescence properties of the as-prepared samples. SEM results indicate that as-obtained samples have perfect spherical morphology with narrow size distribution. PL excitation and emission spectra demonstrated the LaPO4:Ln3+ phosphors show strong light emissions with different colors coming from different activator ions under ultraviolet excitation, which might find potential applications in fields such as light phosphor powders and advanced flat panel displays.

Nano-probe x-ray analysis and high-resolution imaging on planar defects in high-pressure synthesized infinite-layer superconductor

1994 ◽  
Vol 52 ◽  
pp. 728-729
Author(s):  
Y. Y. Wang ◽  
H. Zhang ◽  
V. P. Dravid ◽  
H. Zhang ◽  
L. D. Marks ◽  
...  
Keyword(s):  
High Pressure ◽  
High Resolution ◽  
Atomic Structure ◽  
Emission Spectra ◽  
High Resolution Electron Microscopy ◽  
Planar Defects ◽  
X Ray ◽  
Infinite Layer ◽  
Resolution Electron ◽  
Resolution Imaging

Azuma et al. observed planar defects in a high pressure synthesized infinitelayer compound (i.e. ACuO2 (A=cation)), which exhibits superconductivity at ~110 K. It was proposed that the defects are cation deficient and that the superconductivity in this material is related to the planar defects. In this report, we present quantitative analysis of the planar defects utilizing nanometer probe xray microanalysis, high resolution electron microscopy, and image simulation to determine the chemical composition and atomic structure of the planar defects. We propose an atomic structure model for the planar defects.Infinite-layer samples with the nominal chemical formula, (Sr1-xCax)yCuO2 (x=0.3; y=0.9,1.0,1.1), were prepared using solid state synthesized low pressure forms of (Sr1-xCax)CuO2 with additions of CuO or (Sr1-xCax)2CuO3, followed by a high pressure treatment.Quantitative x-ray microanalysis, with a 1 nm probe, was performed using a cold field emission gun TEM (Hitachi HF-2000) equipped with an Oxford Pentafet thin-window x-ray detector. The probe was positioned on the planar defects, which has a 0.74 nm width, and x-ray emission spectra from the defects were compared with those obtained from vicinity regions.

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