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.

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.

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).

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

Sol-Gel Deposition and Luminescence Properties of Spherical Phosphors Ca2Y8(SiO4)6O2:Eu3+

2008 ◽  
Vol 368-372 ◽  
pp. 378-380
Author(s):  
Xiu Mei Han ◽  
J. Lin ◽  
M. Yu ◽  
C.K. Lin ◽  
Xi Wei Qi ◽  
...  
Keyword(s):  
Grain Size ◽  
Charge Transfer ◽  
Diffraction Analysis ◽  
Charge Transfer Band ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Red Emission ◽  
X Ray ◽  
Average Grain Size ◽  
Sol Gel Process

Spherical SiO2 particles were coated with Ca2Y8(SiO4)6O2:Eu3+ phosphor layers through a sol-gel process. The results of XRD (X-ray diffraction) analysis indicated that the phosphors crystallized completely at 1000oC. AFM study revealed that the average grain size is 500 nm. In Ca2Y8(SiO4)6O2:Eu3+ spherical phosphors , the Eu3+ showed its characteristic red emission at 612 nm(5D0-7F2) upon excitation into its charge transfer band of Eu3+-O2- at 242nm.

scholarly journals Synthesis, Characterization and Photo-Physical Properties of Europium(III) and Terbium(III) Complexes with Thiosemicarbazones

2020 ◽  
Vol 32 (4) ◽  
pp. 952-958
Author(s):  
Ananya Vishwakarma ◽  
S.K. Sengupta ◽  
O.P. Pandey
Keyword(s):  
Physical Properties ◽  
1H Nmr ◽  
Elemental Analysis ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Intense Peak ◽  
Ft Ir

Europium(III) and Terbium(III) complexes of type [Eu(L)Cl(H2O)2] and [Tb(L)OAc(H2O)2] (H2L = thiosemicarbazone ligands derived from substituted thiosemicarbazide and benzil/diacetyl) were synthesized. The ligands and synthesized complexes were characterized on the basis of elemental analysis, FT-IR and 1H NMR and X-ray diffraction studies. Photo-physical properties such as excitation spectra, emission spectra and luminescence curves of complexes were investigated. The most intense peak of Eu3+ ion found at 618 nm attributed to 5D0 → 7F2 transition and peak of Tb3+ ion at 549 nm attributed to 5D4 →7F5 transition.

Red (Eu3+), Green (Tb3+) and Ultraviolet (Gd3+) Emitting Nitrilotriacetate Complexes Prepared by One-step Synthesis

2014 ◽  
Vol 69 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Ivan G. N. Silva ◽  
Hermi F. Brito ◽  
Ernesto R. Souza ◽  
Danilo Mustafa ◽  
Maria C. F. C. Felinto ◽  
...  
Keyword(s):  
Energy Transfer Process ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
Excited Triplet ◽  
X Ray ◽  
Intensity Parameters ◽  
One Step ◽  
Uv Excitation ◽  
Photoluminescence Behavior ◽  
The Eu

The [RE(NTA)(H2O)2]⋅(H2O) rare-earth complexes (RE3+: Eu, Gd, Tb and NTA: nitrilotriacetate) were synthesized and characterized by elemental analysis, thermogravimetry, X-ray diffraction, and infrared spectroscopy. The complexes show high crystallinity and thermostability. The photoluminescence behavior was studied based on the excitation and emission spectra, and luminescence decay curves. The compounds exhibit red (Eu3+), green (Tb3+) and UV (Gd3+) monochromatic emissions under UV excitation. The NTA ligand acts as luminescence sensitizer in the ligand-to- RE3+ intramolecular energy transfer process, owing to the fact that the first excited triplet state (T1: 29 000 cm−1) is located above of the 5D0 (Eu3+) and 5D4 (Tb3+) emitting levels. The experimental intensity parameters Ωλ (λ: 2 and 4) for the Eu3+ NTA complex were calculated, and the results are discussed. The Gd3+-NTA complex exhibits a high-intensity emission band in the UV region (32 000 cm−1) assigned to the 6P7/2→8S7/2 intraconfigurational transition.

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.

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.

scholarly journals Mining Wastes of an Albite Deposit as Raw Materials for Vitrified Mullite Ceramics

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Pedro J. Sánchez-Soto ◽  
Eduardo Garzón ◽  
Luis Pérez-Villarejo ◽  
George N. Angelopoulos ◽  
Dolores Eliche-Quesada
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Phase Evolution ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Mining Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value

In this work, an examination of mining wastes of an albite deposit in south Spain was carried out using X-ray Fluorescence (XRF), X-ray diffraction (XRD), particle size analysis, thermo-dilatometry and Differential Thermal Analysis (DTA) and Thermogravimetric (TG) analysis, followed by the determination of the main ceramic properties. The albite content in two selected samples was high (65–40 wt. %), accompanied by quartz (25–40 wt. %) and other minor minerals identified by XRD, mainly kaolinite, in agreement with the high content of silica and alumina determined by XRF. The content of Na2O was in the range 5.44–3.09 wt. %, being associated with albite. The iron content was very low (<0.75 wt. %). The kaolinite content in the waste was estimated from ~8 to 32 wt. %. The particle size analysis indicated values of 11–31 wt. % of particles <63 µm. The ceramic properties of fired samples (1000–1350 °C) showed progressive shrinkage by the thermal effect, with water absorption and open porosity almost at zero at 1200–1250 °C. At 1200 °C, the bulk density reached a maximum value of 2.38 g/cm3. An abrupt change in the phase evolution by XRD was found from 1150 to 1200 °C, with the disappearance of albite by melting in accordance with the predictions of the phase diagram SiO2-Al2O3-Na2O and the system albite-quartz. These fired materials contained as main crystalline phases quartz and mullite. Quartz was present in the raw samples and mullite was formed by decomposition of kaolinite. The observation of mullite forming needle-shape crystals was revealed by Scanning Electron Microscopy (SEM). The formation of fully densified and vitrified mullite materials by firing treatments was demonstrated.

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