Preparation of CaAl2O4: Eu2+ Long Persistent Blue Phosphor

2007 ◽  
Vol 26-28 ◽  
pp. 573-576 ◽  
Author(s):  
K.S. Bartwal ◽  
B.K. Singh ◽  
H. Ryu
Keyword(s):  
Broad Band ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Persistent Luminescence ◽  
High Brightness ◽  
X Ray ◽  
Blue Phosphor ◽  
Long Duration ◽  
Excited Luminescence ◽  
Luminescence Characteristics

CaAl2O4:Eu2+ with high brightness and long persistent luminescence were prepared by solid state reaction method. The phosphor compositions with varying Eu2+ were investigated by powder X-ray diffractometer (XRD), SEM, TEM, photoluminescence excitation and emission spectra. Broad band UV excited luminescence of the CaAl2O4:Eu2+ was observed in the blue region (λmax = 440 nm) due to transitions from the 4f65d1 to the 4f7 configuration of the Eu2+ ion. The particle size also plays a role deciding the luminescence characteristics of these phosphors. The decay time of the persistence indicated that the persistent luminescence phosphor has bright phosphorescence and maintains a long duration.

scholarly journals Optical Properties of Blue Phosphor

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Mourad Derbal ◽  
Lakhdar Guerbous ◽  
Ouadjaout Djamel ◽  
Chaminade Jean Pierre ◽  
Mohyddine Kadi-Hanifi
Keyword(s):  
Blue Emission ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Photoluminescence Excitation ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Blue Phosphor ◽  
Emission Transition ◽  
Scanning Electron

(, 0.5, 1, 5, and 10 at.%) polycrystalline powders blue phosphors were prepared via the classical solid-state reaction method. X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence excitation, and emission spectra were used to characterize phosphors. By analyzing the excitation and emission spectra of samples, the result indicates that there exists the energy transfer only from the group to the energy level of ion. On the other hand, the influence of the thulium concentration on the blue emission transition and and the emission of group are investigated.

Spherical BaMgAl10O17:Eu2+ Phosphor Particles by Liquid Phase Synthesis

2007 ◽  
Vol 124-126 ◽  
pp. 391-394
Author(s):  
Ha Kyun Jung ◽  
Dae Won Lee ◽  
Yoon Chang Park
Keyword(s):  
Liquid Phase ◽  
Emission Intensity ◽  
Broad Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Phase Reaction ◽  
Uniform Size ◽  
Synthetic Process ◽  
Preparation Conditions ◽  
Blue Phosphor

To improve luminescent properties of the phosphor, spherical BaMgAl10O17:Eu2+ particles have been synthesized using a liquid phase reaction composed of two-stage precipitations. This phosphor particles exhibited uniform size (0.4 ㎛) with narrow distribution and were well-dispersed without agglomeration. The single phase of phosphor was formed by firing at the temperature of about 1350°C. The preparation conditions in this synthetic process for spherical BaMgAl10O17:Eu2+ particles were optimized on the basis of emission intensity by the excitation at 147 nm. The emission spectra showed the typical broad band due to the transition of Eu2+ activator from 4f65d1 to 4f7 in BaMgAl10O17:Eu2+. The maximum emission intensity for this spherical blue phosphor was obtained by reduction treatment at 1450°C.

Synthesis and luminescence properties of red-emitting K2MgSiO4:Eu3+ phosphors

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744058
Author(s):  
Rong Yang ◽  
Huidong Tang
Keyword(s):  
Decay Curve ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Excitation Spectra ◽  
Red Phosphor ◽  
Light Emitting ◽  
X Ray ◽  
Dipole Interactions ◽  
Near Ultraviolet ◽  
White Light Emitting Diodes

A novel phosphor, K2MgSiO4:Eu[Formula: see text], was synthesized by a solid-state reaction method. The phase formation was checked by X-ray powder diffraction. The photoluminescence excitation, emission spectra, decay curve and CIE coordinates of samples with different Eu[Formula: see text] ion concentrations were investigated in detail. The excitation spectra show a broad wavelength range of 225–470 nm. The K2MgSiO4:Eu[Formula: see text] phosphors exhibit highly red emission peaking at about 616 nm which is assigned to the 5D[Formula: see text]F2 transition of Eu[Formula: see text]ions under the excitation of near-ultraviolet (NUV) (394 nm) light. The critical quenching concentration of Eu[Formula: see text] doped in the K2MgSiO4: Eu[Formula: see text] phosphors was about 10 mol.% and the concentration quenching mechanism was dipole–dipole interactions between Eu[Formula: see text] ions. The results indicate that K2MgSiO4:Eu[Formula: see text] is a potential red phosphor candidate for NUV-pumped white light emitting diodes.

A New Deep Red-Emitting Mn2+-Activated SrLaGa3S6O Phosphor

2012 ◽  
Vol 531-532 ◽  
pp. 145-148 ◽  
Author(s):  
Rui Jin Yu ◽  
Jin Young Park ◽  
Hyun Kyoung Yang ◽  
Byung Kee Moon ◽  
Byung Chun Choi ◽  
...  
Keyword(s):  
Broad Band ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
White Led ◽  
Photoluminescence Excitation ◽  
Led Lighting ◽  
Display Devices ◽  
Chromaticity Coordinates ◽  
Standard Values ◽  
Cie Chromaticity

A new deep red-emitting Mn2+-activated SrLaGa3S6O phosphor was first prepared by a solid-state reaction method. Their luminescence properties were investigated by photoluminescence excitation and emission spectra. The emission spectrum shows a broad band with an emission maximum at 668 nm under the host excitation of 340 nm. The full width at half maximum (FWHM) of the emission peak is about 83 nm. The CIE chromaticity coordinates (x = 0.673 and y = 0.312) shows that the phosphor emission is in the deep red region and were very near to the NTSC standard values for red. Since the excitation band of the phosphor lies in the near UV excitable region, giving a deep red emission, it can be used for applications in near UV phosphor converted white LED lighting and display devices.

Enhancing the Photocatalytic Activity of La/Y Co-Doped ZnWO4 under UV Irradiation

2020 ◽  
Vol 842 ◽  
pp. 214-222
Author(s):  
Chu Wen Rao ◽  
Wei Zhang ◽  
Zheng Fa Hu ◽  
Zu Yong Feng ◽  
Ying Jun Chen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Uv Irradiation ◽  
Photoelectron Spectroscopy ◽  
Broad Band ◽  
Solid State Reaction Method ◽  
High Photocatalytic Activity ◽  
Photocatalytic Decomposition ◽  
X Ray ◽  
Co Doping ◽  
Broad Band Emission

In this paper, ZnWO4: La3+, Y3+ photocatalysts were synthesized by a high-temperature solid state reaction method. The effects of La3+ and Y3+ doping contents on the phase, morphologies and optical properties of the samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Diffuse reflectance spectra (DRS), photoluminescence spectra (PL), Raman and UV-visible spectroscopy, respectively. The as-prepared ZnWO4:La3+, Y3+ photocatalysts showed photoluminescence with a broad band emission, and high photocatalytic activity in degradation of rhodamine B (RhB) under simulated UV irradiation. The results showed that co-doping in ZnWO4 can enhance light harvesting capability to generate more electron-hole pairs, and acted as a trap center by decreasing the recombination of photogenerated electrons and holes. All the results obtained by the work suggest that ZnWO4: La3+, Y3+ photocatalysts are promising materials for the photocatalytic decomposition of pollutants.

Influence of Eu2+ Doped Contents on the Spectroscopic Features of Sr2-X MgSi2O7:xEu2+

2012 ◽  
Vol 476-478 ◽  
pp. 1232-1236
Author(s):  
Jia Zhe Guo ◽  
Ya Dong Li ◽  
Yan Lin Huang
Keyword(s):  
Emission Spectra ◽  
Optical Excitation ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Broad Absorption ◽  
Broad Absorption Band ◽  
Phase Purity ◽  
Reaction Method ◽  
X Ray ◽  
Uv Led

Silicate-based Sr2-xMgSi2O7:xEu2+(x=0.01, 0.03, 0.05, 0.07) phosphors were synthesized by the high temperature solid-state reaction method. Phase purity and crystal structure of the phosphors were characterized using X-ray diffraction spectrometer. The optical excitation and emission spectra of Eu2+ ion were measured using luminescence spectrometer and fluorescence spectrophotometer. The emission spectra showed a strong blue luminescence peaked around 470 nm, corresponds to the 4f65d1 →4f7 transition on Eu2+. Two different average decay time confirmed that the Eu2+ cations may occupy in two different lattice sites and presents different spectroscopic features. With a broad absorption band extending from 224 to 450 nm, it is suggestive that the phosphors have a potential application in UV-LED chips (360-400 nm).

scholarly journals Broad-band spectral analysis of LMXB XTE J1710−281 with Suzaku

2020 ◽  
Vol 496 (1) ◽  
pp. 197-205
Author(s):  
Prince Sharma ◽  
Rahul Sharma ◽  
Chetana Jain ◽  
Anjan Dutta
Keyword(s):  
Spectral Analysis ◽  
Broad Band ◽  
Emission Spectra ◽  
Band Spectrum ◽  
Surface Boundary ◽  
Hot Electron ◽  
Spectral Parameters ◽  
Surface Boundary Layer ◽  
X Ray ◽  
Single Temperature

ABSTRACT This work presents the broad-band time-averaged spectral analysis of neutron star (NS) low-mass X-ray binary, XTE J1710−281 by using the Suzaku archival data. The source was in a hard or an intermediate spectral state during this observation. This is the first time that a detailed spectral analysis of the persistent emission spectra of XTE J1710−281 has been done up to 30 keV with improved constraints on its spectral parameters. By simultaneously fitting the X-ray Imaging Spectrometer (0.6–9.0 keV) and the HXD-PIN (15.0–30.0 keV) data, we have modelled the persistent spectrum of the source with models comprising a soft component from accretion disc and/or NS surface/boundary layer and a hard Comptonizing component. The 0.6–30 keV continuum with neutral absorber can be described by a multicolour disc blackbody with an inner disc temperature of kTdisc = 0.28 keV, which is significantly Comptonized by the hot electron cloud with electron temperature of kTe ≈ 5 keV and described by photon index Γ = 1.86. A more complex three-component model comprising a multicolour disc blackbody ≈0.30 keV, single-temperature blackbody ≈0.65 keV, and Comptonization from the disc, partially absorbed (about 38 per cent) by an ionized absorber (log(ξ) ≈ 4) describes the broad-band spectrum equally well.

Photoluminescence properties of Li2+xNb3xTi1−4xO3:Eu3+

2019 ◽  
Vol 12 (04) ◽  
pp. 1950057 ◽  
Author(s):  
Chao-Chao Guo ◽  
Qun Zeng ◽  
Chun-Feng Yao ◽  
Yan-Zhao Feng ◽  
Xi Chen ◽  
...  
Keyword(s):  
Solid State ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Red Emission ◽  
Reaction Method ◽  
X Ray ◽  
Red Phosphors ◽  
Chromaticity Coordinate

Red phosphors with compositions of Li[Formula: see text]Nb[Formula: see text]Ti[Formula: see text]O3:3[Formula: see text]wt.% Eu[Formula: see text] [Formula: see text] were synthesized by solid-state reaction method. The samples were investigated by using X-ray diffraction (XRD) and photoluminescence spectroscopy, respectively. XRD results showed that all samples were main phase of Li2TiO3. Emission spectra of Li[Formula: see text]Nb[Formula: see text]Ti[Formula: see text]O3:3[Formula: see text]wt.% Eu[Formula: see text] powders showed strong red emission at 612[Formula: see text]nm (5D0–7F[Formula: see text] with 396[Formula: see text]nm excitation. In addition, the excitation and emission intensity increased up to [Formula: see text], and then decreased with further increasing of the x values. And the chromaticity coordinate (CIE) of the component with [Formula: see text] was superior to other components.

scholarly journals Synthesis, Luminescent Properties and White LED Fabrication of Sm3+ Doped Lu2WMoO9

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 403
Author(s):  
Zijun Chen ◽  
Huiyi Xu ◽  
Chunyan Cao ◽  
Xiaoting Chen ◽  
Min Zhang ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
White Led ◽  
X Ray Diffraction ◽  
Nonradiative Relaxation ◽  
Temperature Dependent ◽  
X Ray ◽  
Xrd Patterns ◽  
Synthesized Materials

In this paper, Sm3+ doped Lu2W0.5Mo0.5O6, Lu2WMoO9, and Lu2(W0.5Mo0.5O4)3 materials were synthesized by using a two-step solid-state reaction method. The synthesized materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electronic micrograph (FE-SEM) pictures, photoluminescence (PL) excitation and emission spectra, and temperature-dependent emission intensities. Orange-reddish light could be observed from the phosphors under ultraviolet (UV) 365 nm light. The Sm3+ doped Lu2WMoO9 had enhanced PL intensities compared to the other two materials. The excitation, the energy transfer, the nonradiative relaxation, and the emission processes were illustrated by using schematic diagrams of Sm3+ in Lu2MoWO9. The optimal Sm3+ doping concentration was explored in the enhancing luminescence of Lu2WMoO9. By combing the Sm3+ doped Lu2WMoO9 to UV 365 nm chips, near white lighting emitting diode (W-LED) were obtained. The phosphor can be used in single phosphor-based UV W-LEDs.

scholarly journals New synchrotron powder diffraction facility for long-duration experiments

2017 ◽  
Vol 50 (1) ◽  
pp. 172-183 ◽  
Author(s):  
Claire A. Murray ◽  
Jonathan Potter ◽  
Sarah J. Day ◽  
Annabelle R. Baker ◽  
Stephen P. Thompson ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Large Scale ◽  
Large Area ◽  
High Brightness ◽  
X Ray ◽  
Area Detector ◽  
Synchrotron Powder Diffraction ◽  
Long Duration ◽  
Slow Kinetic

A new synchrotron X-ray powder diffraction instrument has been built and commissioned for long-duration experiments on beamline I11 at Diamond Light Source. The concept is unique, with design features to house multiple experiments running in parallel, in particular with specific stages for sample environments to study slow kinetic systems or processes. The instrument benefits from a high-brightness X-ray beam and a large area detector. Diffraction data from the commissioning work have shown that the objectives and criteria are met. Supported by two case studies, the results from months of measurements have demonstrated the viability of this large-scale instrument, which is the world's first dedicated facility for long-term studies (weeks to years) using synchrotron radiation.

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