Comparable Structural and Luminescent Characterization of the La1-xEuxVO4 Solid Solutions Synthesized by Solid State and Co-Precipitation Methods

2013 ◽  
Vol 200 ◽  
pp. 186-192 ◽  
Author(s):  
Oksana Chukova ◽  
Sergiy G. Nedilko ◽  
Sergiy A. Nedilko ◽  
Vasyl Sherbatsky ◽  
Tetiana Voitenko
Keyword(s):  
Solid State ◽  
Solid Solutions ◽  
Spectral Lines ◽  
Luminescence Properties ◽  
Luminescence Spectra ◽  
Excitation Spectra ◽  
Electron Transitions ◽  
Charge Transfer Transitions ◽  
The Matrix ◽  
Co Precipitation

Luminescence properties of the two series of the La1-xEuxVO4 (x ranges from to 0.3) solid solutions synthesized by the solid state and co-precipitation methods were investigated.. Luminescence spectra of the investigated samples consist of narrow spectral lines caused by inner f - f electron transitions in the impurity Eu3+ ions. Excitation spectra consist of three main bands those correspond to different types of transitions in the investigated matrices. There are O - Eu3+ charge transfer transitions, band-to-band transitions in the matrix of the vanadate compounds and electron transitions in the VO43- vanadate anion. Dependences of the structure and luminescence properties on rate compositions and method of synthesis were studied. Origins of the observed differences between luminescence characteristics of the samples obtained by two different methods are discussed.

Study of Temperature Behavior of Luminescence Emission of LaVO4 and La1-xEuxVO4 Powders

2015 ◽  
Vol 230 ◽  
pp. 153-159 ◽  
Author(s):  
Oksana Chukova ◽  
Sergiy G. Nedilko ◽  
Sergiy A. Nedilko ◽  
Tetiana Voitenko ◽  
Olga Gomenyuk ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Spectral Lines ◽  
Temperature Behavior ◽  
Precipitation Method ◽  
Temperature Range ◽  
Luminescence Emission ◽  
Electron Transitions ◽  
The Matrix ◽  
Co Precipitation ◽  
The Eu

The La1‑xEuxVO4 powders were synthesized by co-precipitation method. Emission spectra of the LaEuVO4 and La1‑xEuxVO4 powders consist of wide non-structural bands of the matrix emission and narrow spectral lines caused by inner f-f electron transitions in the Eu3+ ions, respectively. The both types of emission were studied within 8 – 300 K temperature range. Decomposition of spectra of the wide matrix emission on three bands has been carried out and temperature dependencies for each band were studied. Temperature behavior of the Eu3+ emission was investigated for lines assigned to different Eu3+ centres. Obtained dependencies are analyzed and discussed using proposed schemes of transitions in the VO43- groups and structure of the nearest surrounding of the Eu3+ emission centres.

Luminescence Properties of the Yttrium and Gadolinium Tantalo-Niobates

2015 ◽  
Vol 230 ◽  
pp. 172-177 ◽  
Author(s):  
Olesia Voloshyna ◽  
Ianina Boiaryntseva ◽  
Dmitry Spassky ◽  
Oleg Sidletskiy
Keyword(s):  
Solid State ◽  
Synchrotron Radiation ◽  
Solid Solutions ◽  
Solid State Synthesis ◽  
Luminescence Properties ◽  
X Ray ◽  
Ceramic Samples

Ceramic samples of tantalo-niobates solid solutions with yttrium and gadolinium cations (RE(NbxTa1-x)O4, RE = Y or Gd, and x=0÷1) have been obtained by solid-state synthesis. Luminescence properties of yttrium and gadolinium tantalo-niobates under X-ray and synchrotron radiation, UV and VUV radiation have been studied in visible and UV spectral regions. The luminescence mechanisms in yttrium and gadolinium tantalo-niobates have been determined as well.

scholarly journals Synthesis and Luminescence Properties of La2O2S:RE3+ (RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) Submicron Size Phosphors for Lamp Industry

2020 ◽  
Vol 9 (4) ◽  
pp. 1898-1907
Keyword(s):  
Solid State ◽  
Broad Band ◽  
Blue Emission ◽  
Luminescence Properties ◽  
Excitation Spectra ◽  
Yellow Band ◽  
Broad Band Emission ◽  
Band Emission ◽  
Ft Ir ◽  
Down Conversion

RE3+(RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) doped La2O2S phosphors was synthesized by solid state flux fusion method and their down conversion spectral properties were studied as a function different RE3+ concentrations and reported in this paper. The solid state flux fusion results in well crystallized hexagonal shaped phosphor particles. The samples were characterized by XRD, SEM, FT-IR photoluminescence (PL) and CIE colour co-ordinates techniques. The lanthanum oxysulphide (La2O2S) phosphor doped with Ce3+ shows broad band emission with peak at 390 nm and 415 nm when excited at 340 nm excitation. La2O2S:Dy3+ shows efficient blue and yellow band emissions at 480 nm and 572 nm. La2O2S:Eu3+ phosphor shows an orange and red emission at 590 nm and 615 nm. Whereas La2O2S:Tb3+ phosphor shows weak blue emission at 488 nm and strong green 545 nm. The excitation spectra used for the La2O2S:RE3+ (where RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) phosphors is in the near UV region extending from 350 to 400 nm, which is characteristics of near UV excited LED. The effect of the RE3+ (RE3+= Ce3+, Dy3+ , Eu3+ and Tb3+) concentration on the luminescence properties of La2O2S:RE3+ phosphors were also studied. The investigated prepared La2O2S phosphors may be suitable for a near UV excited W-LED. Keywords: Oxysulphide, SEM, FT-IR, PL, SSL, CIE.

Luminescence properties of La2W2−xMoxO9 (x = 0–2):Eu3+ materials and their Judd–Ofelt analysis: novel red line emitting phosphors for pcLEDs

2017 ◽  
Vol 1 (3) ◽  
pp. 550-561 ◽  
Author(s):  
Kasturi S. ◽  
Sivakumar V.
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Emission Intensity ◽  
Luminescence Properties ◽  
Precipitation Technique ◽  
Co Precipitation ◽  
Red Line

The emission intensity of a Eu1.6La0.4W1.6Mo0.4O9 phosphor, synthesized by a co-precipitation technique, was found to be ∼1.78 times higher than that of the phosphor synthesized by a solid state reaction.

EVOLUTION OF LUMINESCENCE SPECTRA OF Ce3+-ION IN THE SOLID SOLUTIONS Ca1-xSrxS

2006 ◽  
Vol 20 (22) ◽  
pp. 1405-1416 ◽  
Author(s):  
O. KRACHNI ◽  
L. GUERBOUS ◽  
L. LOUAIL
Keyword(s):  
Band Gap ◽  
Lattice Constant ◽  
Solid Solutions ◽  
Local Structure ◽  
Emission Spectra ◽  
Host Lattice ◽  
Luminescence Properties ◽  
Luminescence Spectra ◽  
Additional Band

Luminescence spectra of Ce 3+-ion in Ca 1-x Sr x S solid solutions have been investigated. It has been shown that the evolution of Ce 3+ excitation and emission spectra through the concentration range may be interpreted in correlation with the variations, with the host lattice composition, of the lattice constant, the local structure in the activator neighborhood and the band gap. Under activator excitation, in addition to the two conventional bands, an additional band peaking at about 650 nm was observed (mainly in SrS ) and was related to the contamination of the samples as a consequence of extended storage. Except for this band, the luminescence properties did not change relatively to those obtained previously on the same samples. The most drastic modification affected SrS:Ce 3+, despite the fact that all the samples have been stored in the same conditions.

Luminescence properties of newly developed red-emitting phosphors M2Si2O7:Eu3+ (M=La, Y) under UV/VUV excitation

2006 ◽  
Vol 916 ◽  
Author(s):  
Zhiya Zhang ◽  
Yuhua Wang
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Luminescence Properties ◽  
Color Purity ◽  
Excitation Spectra ◽  
Reaction Method

AbstractThe red-emitting phosphors of Eu3+ doped M2Si2O7 (M=La, Y) were synthesized by a solid-state reaction method and their luminescence properties in UV-VUV region have been studied. On the excitation spectra, the Eu3+-O2- CT band is of higher intensity for La2Si2O7, while for Y2Si2O7, the absorption around 150nm is much stronger and this can be assigned to the Y3+-O2- CT band in company with the Si-O group absorption. The emission spectra show higher intensity and better color purity for La2Si2O7:Eu3+ under 254nm excitation due to Eu3+ occupying the non-centrosymmetric site. Under 147nm excitation, Y2Si2O7:Eu3+ exhibits stronger emission with purer red, which can be corresponded to the absorption of Y3+-O2- CT in the VUV region.

Investigation Of Luminescence And Absorption Spectra Of Bedt-Ttf And Its Ion Radical Salt

1993 ◽  
Vol 328 ◽  
Author(s):  
M. E. Kozlov ◽  
Y Tanaka ◽  
M. Tokumotot ◽  
T. Tani
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Low Temperature ◽  
Absorption Spectra ◽  
Emission Intensity ◽  
Luminescence Spectra ◽  
Charged State ◽  
Excitation Spectra ◽  
Radical Salt ◽  
Temperature Solution

ABSTRACTLuminescence with maximum near 1.96 eV of organic donor compound bis (ethylenedi-thio) tetrathiafulvalene (BEDT-TTF) was observed in crystals and frozen at low temperature solution. It was found that solid state effects sharply reveal themselves in excitation spectra of the substance and have almost no influence on the shape of the emission. Intensity of the emission is strong at liquid He temperature but rapidly decreases with heating of the sample as well as after modification of charged state of molecules forming the crystal and is very weak in case of Monovalent (BEDT-TTF) Br salt. Shape of the luminescence spectra correlates with the absorption of the investigated compounds. The data obtained can be interpreted assuming dimer-like arrangement of molecules in the crystal structure.

scholarly journals Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Aleksandr Kalinko ◽  
Alexey Kotlov ◽  
Alexei Kuzmin ◽  
Vladimir Pankratov ◽  
Anatoli Popov ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Solid Solutions ◽  
Vacuum Ultraviolet ◽  
Localized States ◽  
Electronic Excitations ◽  
Photoluminescence Band ◽  
Excitation Spectra ◽  
X Ray ◽  
Electron Transitions ◽  
The One

AbstractThe photoluminescence spectra and luminescence excitation spectra of pure microcrystalline and nano-sized ZnWO4 as well as the ZnxNi1−x WO4 solid solutions were studied using vacuum ultraviolet (VUV) synchrotron radiation. The samples were also characterized by x-ray powder diffraction. We found that: (i) the shape of the photoluminescence band at 2.5 eV, being due to radiative electron transitions within the [WO6]6− anions, becomes modulated by the optical absorption of Ni2+ ions in the ZnxNi1−x WO4 solid solutions; and (ii) no significant change in the excitation spectra of Zn0.9Ni0.1WO4 is observed compared to pure ZnWO4. At the same time, a shift of the excitonic bands to smaller energies and a set of peaks, attributed to the one-electron transitions from the top of the valence band to quasi-localized states, were observed in the excitation spectrum of nano-sized ZnWO4.

Luminescent Properties of Re2SiO4:Tm3+ (Re=Mg,Ba,Sr) Under VUV

2008 ◽  
Vol 368-372 ◽  
pp. 372-374
Author(s):  
Peng Zhi Lu ◽  
Da Wei He ◽  
Xin Li ◽  
Yong Sheng Wang
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Powder Diffraction ◽  
Luminescent Properties ◽  
Host Lattice ◽  
Excitation Band ◽  
Excitation Spectra ◽  
Broad Excitation Band ◽  
X Ray ◽  
Charge Transfer Transitions

New phosphors of Tm3+ doped Re2SiO4 (Re=Mg, Ba, Sr) were prepared by the solid-state reaction and their luminescent properties were investigated. X-ray powder diffraction analysis confirmed the formation of Re2SiO4: Tm3+ (Re=Mg, Ba, Sr). The excitation spectra indicated that this phosphor can be effectively excited by 161nm. It consists of peaked at 175nm and a broad excitation band from 184nm to 300nm, corresponded to the absorption of the host lattice and the O−Tm3+ charge transfer transitions. The emission peaks at about 357nm, 459nm, 485nm is separately corresponds to the 1D2 → 3H6, 1D2 → 3H4, 1G4 → 3H6 transitions of Tm3+. As the radius of alkali earth ion in Re site increases, the main emission peaks changed to 478nm from 459nm.

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