scholarly journals Synthesis and Luminescent Properties of Eu3+/Tb3+ Rare Earth Ions Doped Li2SrSiO4 Phosphors

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Kaitao Yu ◽  
Lifang Wei ◽  
Jiaqi Shen
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
Excitation Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Uv Visible

The series of luminescent materials of Eu3 +, Tb3 + doped Li2SrSiO4 were synthesized by a high-temperature solid-state method. The phase purity of the samples was measured by X-ray powder diffraction (XRD). The luminescent properties of the samples were studied by UV-visible excitation spectra and emission spectra The It is found that the strong absorption of Eu3 + doped Li2-xSr1-xEuxSiO4 is from the 250 ~ 290 nm charge transfer band of Eu3 + and the 7F0 → 5L6 absorption transition of 393 nm. The strongest emission of the emission spectra at 393 nm is 614 nm and 701 nm, respectively, from the 5D0 → 7F2 and 5D0 → 7F4 transitions of Eu3 +. Tb3 + doped sample Li2-xSr1-xTb xSiO4 excitation spectrum is mainly composed of Tb3 + ion fd transition and charge transfer band composed of broadband, the strongest absorption at 269 nm, the emission of the main emission of 5D4 → 7F5 transition (542 nm).

Study on UV Excitation Properties of Y2O3:Ln3+ (Ln = Eu3+ or Tb3+) Luminescent Nanomaterials

2008 ◽  
Vol 8 (3) ◽  
pp. 1443-1448 ◽  
Author(s):  
Qingyu Meng ◽  
Baojiu Chen ◽  
Xiaoxia Zhao ◽  
Xiaojun Wang ◽  
Wu Xu
Keyword(s):  
Particle Size ◽  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
Excitation Spectra ◽  
X Ray ◽  
Long Wavelength ◽  
Uv Excitation

Y2O3:Ln3+ (Ln = Eu or Tb) nanocrystals with different Ln3+ doping concentrations and average sizes were prepared by chemical self-combustion. The corresponding bulk materials with various doping concentrations were obtained by annealing the nanomaterials at high temperature. The emission spectra, excitation spectra, and X-ray diffraction spectra were used in this study. It was found that the charge transfer band of Y2O3:Eu3+ red-shifted as particle size decreased, and the charge transfer band in the 5-nm particles obviously broadened toward the long wavelength. It was also found that the profile of excitation spectra corresponding to the 4f5d (4f8 → 4f75d1) transition changed a lot with the variation of the particle size. The dependence of the excitation spectra of Y2O3:Ln3+ on particle size was investigated.

scholarly journals Photoluminescence and piezoelectricity investigation of La1.98Nd0.02Ti2O7, Sm1.98Ce0.02Ti2O7 and Er1.98Gd0.02Ti2O7 multifunctional materials

2019 ◽  
Vol 37 (4) ◽  
pp. 607-614
Author(s):  
Esra Öztürk ◽  
Ebru Sarilmaz
Keyword(s):  
Curie Temperature ◽  
Piezoelectric Properties ◽  
Electrical Characterization ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray

AbstractNd3+ doped La2Ti2O7, Ce4+ doped Sm2Ti2O7 and Gd3+ doped Er2Ti2O7 have been synthesized at different reaction temperatures using solid state reaction method, and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA), thermogravimetric analysis (TG). Excitation spectra, emission spectra and decay time curves of the samples were investigated by photoluminescence spectrophotometer (PL) and typical transitions of rare earth ions were observed. Dielectric properties, piezoelectric properties and Curie temperature of the obtained luminescent materials were measured for electrical characterization. The results showed that all materials have both photoluminescent and piezoelectric properties and show high Curie temperature.

Luminescent Properties of La3PO7:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1410-1413 ◽  
Author(s):  
Shaozhe Lü ◽  
Jishen Zhang
Keyword(s):  
Charge Transfer Band ◽  
Emission Spectra ◽  
Local Environment ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Time Resolved ◽  
Transmission Electron ◽  
Light Excitation ◽  
Average Size

La3PO7:Eu3+ samples were prepared by combustion and annealing and characterized by X-ray diffraction and transmission electron microscopy. It was found that the average size of the particles is about 80 nm. The red emission from the 5D0 → 7F2 transition of the Eu3+ ions under ultraviolet light excitation is much stronger than the orange emission from the 5D0 → 7F1 transition. The emission spectra, charge transfer band, laser selective excitation spectra, and time-resolved spectra indicate that symmetry of the local environment of Eu3+ lacks an inversion center and Eu3+ ions occupy at least two types of sites in the La3PO7 crystal. The superior color chromaticity compared to other phosphates and borates doped with Eu3+ means La3PO7:Eu3+ may have potential as a luminescent material.

Influence of Different Auxiliary Activators Doping on Spectral Properties of Sr3Al2O6: Eu2+ Phosphors

2012 ◽  
Vol 601 ◽  
pp. 54-58 ◽  
Author(s):  
Chao Xu ◽  
Dian Qing Lu ◽  
Hai Feng Jiang
Keyword(s):  
Spectral Properties ◽  
Emission Spectra ◽  
Luminescent Materials ◽  
X Ray Diffraction ◽  
Crystallographic Site ◽  
Excitation Spectra ◽  
X Ray ◽  
Efficient Energy ◽  
Long Afterglow ◽  
Energy Transfers

The long afterglow luminescent materials Sr3Al2O6: Eu2+, Re3+ ( Re= La, Ce, Pr, Nd, Sm, Gd, Dy, Er) were synthesized via solid-state reaction. X-ray diffraction and fluorescence spectrophotometer were employed to characterize the phosphors. The excitation spectra were all well simulated by eight Gaussian curves, indicating that they originated from the 4f7 (8S7/2) – 4f65d (8HJ) transitions of Eu2+ ions. The excitation spectra intensity of Sr3Al2O6: Eu2+, Sm3+ is much stronger than the others, which indicates that there is a more efficient energy transfers from Sm3+ to Eu2+. The simulated results of the emission spectra showed that they generated from the Eu2+ ions in the Sr2+ sites of SrO6 and SrO7 polyhedral, which indicated that the Eu2+ ions were apt to occupy low-coordination crystallographic site. The proposed explanation for excitation spectra and emission spectra property were also discussed

Luminescent Properties of As-Grown and Vacuum Annealed LiNbO3 Single Crystals

2013 ◽  
Vol 200 ◽  
pp. 199-202
Author(s):  
Dmytro Yu. Sugak ◽  
Andriy P. Luchechko
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Annealed Sample ◽  
Luminescence Spectra ◽  
Excitation Spectra ◽  
X Ray ◽  
Grown Sample ◽  
Different Types

This paper reports on the luminescent properties of the congruent as-grown and vacuum annealed LiNbO3 single crystals at the UV and X-ray excitations. The shape of excitation spectra is similar for all emission bands in as-grown sample as well as in vacuum annealed sample. The emission spectra (exc=235 nm) observed in the spectral region 250…800 nm at room temperature consist of five elementary bands. Correlation of the relative intensities bands in luminescence spectra under different types of excitation and their temperature dependencies were determined. The most intensitive maxima in as-grown sample are observed at 295 and 691 nm. The main maximum after vacuum annealing is peaked around 295 nm.

scholarly journals IR luminescence of CaGa 2O 4 : Yb 3+ excited by 940 and 980 nm radiation

2020 ◽  
Vol 6 (1) ◽  
pp. 31-36
Author(s):  
Ul’ana A. Mar’ina ◽  
Viktor A. Vorob’ev ◽  
Alexandr P. Mar’in
Keyword(s):  
Luminescence Intensity ◽  
Level Structure ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescence Spectra ◽  
Practical Implementation ◽  
Luminescent Materials ◽  
Solid State Method ◽  
Region Data

Existing calcium gallate CaGa2O4 based luminescent materials radiating in visible IR region have been reviewed. IR luminophores have been studied but slightly but their practical implementation is of interest. CaGa2O4 specimens activated with Yb3+ rare-earth ions have been synthesized using the solid-state method. The structure and luminescent properties of CaGa2O4 : Yb3+ have been studied. CaGa2O4 : Yb3+ excitation with 940 and 980 nm radiation generates luminescence in the 980–1100 nm region. Data on the electron level structure in Yb3+ ions suggest that the excitation and luminescence occur directly in the Yb3+ ions with only a passive role of the base lattice. The luminescence spectra contain three peaks at 993, 1025 and 1080 nm. These luminescence peaks are caused by electron optical transitions from excited to main state in Yb3+ ions. 993 nm band luminescence intensity has been studied as a function of Yb3+ activator ions concentration. Introduction of Na+ ions into the luminophore increases IR luminescence intensity. Optimum (Ca1-x-yYbxNay)Ga2O4 luminophore composition has been suggested at which the 993 nm luminescence intensity is the highest.

scholarly journals Structural Investigation of Crystalline Host Phosphor Cadmium Tellurite Systems

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Rosli Hussin ◽  
Ng Siang Leong ◽  
Nur Shahira Alias
Keyword(s):  
Crystal Structure ◽  
Luminescent Properties ◽  
Transition Metal Ions ◽  
Rare Earth Ions ◽  
Molar Ratio ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Physical And Chemical

Generally, the luminescent properties of phosphors are strongly dependent on the crystal structure of the host materials. Finding a stable crystal structure, high physical and chemical stability of crystalline matrix is still a critical step to obtain rare-earth ions or transition metal ions-doped persistent phosphor with excellent properties. The glassceramic materials based on cadmium tellurite developed for stable host phosphor is reported in this paper. The structure of TeO2 and CdO-TeO2 system has been investigated by means of FT-Raman, Infrared (IR) spectroscopy and x-ray diffraction (XRD) spectroscopies. Cadmium tellurite system were prepared with the compositions of xCdO-(1-x)TeO2 with 0.1 x 0.5 in percent molar ratio, doped with 1% mol MnO2, using solid state method. The x-ray diffraction measurement results showed that the phase in the cadmium tellurite system matched quite well with the standard ICDD files, indicating that the phases present in this sample appeared to be a phase of -TeO4 trigional bipyramid (tbp), CdTe2O5 and CdTeO3. The Raman and Infrared spectra show that the structures are mainly builds by TeO4 (tbp) groups,TeO3+1 trigional pyramid (tp) and TeO3 (tp), while Cd2+ ions play as network modifiers. As addition concentration of CdO increases, TeO4 (tbp) groups progressively change polymerized framework structure in TeO4 (tbp) into TeO3+1 trigional pyramid (tp) and TeO3 (tp). On the contrary, the addition of 1 mol % MnO2 into the sample did not giving any effect on the structural of the final samples.

Preparation and Luminescent Properties of Polymer Fibers Containing Y2O3:Eu Nanoparticles by Electrospinning

2008 ◽  
Vol 8 (11) ◽  
pp. 6017-6022 ◽  
Author(s):  
Hongquan Yu ◽  
Hongwei Song ◽  
Guohui Pan ◽  
Libo Fan ◽  
Suwen Li ◽  
...  
Keyword(s):  
Weak Interactions ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Average Diameter ◽  
Radiative Transition ◽  
Polymer Fibers ◽  
Composite Fibers ◽  
Defect States ◽  
Excitation Spectra

In this paper, composite fibers of polyvinylpyrrolidone (PVP) and Y2O3:Eu3+ nanocrytals were prepared by electrospinning and characterized by electron microscope, Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD). The composite fibers are in random orientation and with average diameter of ∼300 nm and length up to several ten micrometers. The luminescent properties were investigated and compared with the pure Y2O3:Eu3+ nanocrystals. Due to certain weak interactions between nanocrystals and PVP matrix, charge transfer band in the excitation spectra show slightly red shift for the fibers relative to in the case of pure Y2O3:Eu3+ nanocrystals. The PVP polymer may modified the surface defect states of nanocrystals, yielding decreased intensity ratio of 5D0–7F2 to 5D0–7F1 transition in the emission spectra. The fluorescence lifetimes of 5D0 level for Eu3+ in the composite fibers and Y2O3:Eu3+ nanocrystals were respectively determined to be 1.40 and 1.74 ms. The decreased fluorescence lifetime in the composite fibers was attributed to increased radiative transition rate, as result of the influence of refractive index of the surrounding PVP media instead of air.

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.

Synthesis and Luminescent Properties of Gd2MoO6:Eu3+

2015 ◽  
Vol 15 (10) ◽  
pp. 7765-7769 ◽  
Author(s):  
Sook Hyun Kwon ◽  
Byung Kee Moon ◽  
Jung Hyun Jeong ◽  
Hyun Kyoung Yang ◽  
Jung Hwan Kim
Keyword(s):  
Charge Transfer Band ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Light Emitting ◽  
Diffraction Patterns ◽  
White Light Emitting Diodes ◽  
Electron Microscope Image

A series of 6 mol% Eu3+ doped Gd2MoO6 samples were prepared by using the sol–gel method. The X-ray diffraction patterns of the samples confirmed their monoclinic structure after they were annealed at 1300 °C, and a scanning electron microscope image revealed closely packed particles. The excitation spectra showed that the intensity of the excitation band decreased and the charge transfer band shifted from 370 to 350 nm with decreasing sintering temperature. The emission spectra are dominated by the hypersensitive forced electron dipolar transition 5D0 → 7F2 at 612 nm. The as synthesized phosphor can be used as a red phosphor in white light emitting diodes.

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