scholarly journals SrAl2O4:Eu2+(,Dy3+) Nanosized Particles: Synthesis and Interpretation of Temperature-Dependent Optical Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Huayna Terraschke ◽  
Markus Suta ◽  
Matthias Adlung ◽  
Samira Mammadova ◽  
Nahida Musayeva ◽  
...  
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Emission Spectra ◽  
Green Emission ◽  
Spectroscopic Properties ◽  
Host Lattice ◽  
Nanosized Particles ◽  
Temperature Dependent ◽  
Excitation Spectra ◽  
Blue Emission Band

SrAl2O4nanosized particles (NPs) undoped as well as doped with Eu2+and Dy3+were prepared by combustion synthesis for the discussion of their intensively debated spectroscopic properties. Emission spectra of SrAl2O4:Eu2+(,Dy3+) NPs are composed by a green band at 19 230 cm−1(520 nm) at room temperature, assigned to anomalous luminescence originated by Eu2+in this host lattice. At low temperatures, a blue emission band at 22 520 cm−1(444 nm) is observed. Contrary to most of the interpretations provided in the literature, we assign this blue emission band very reliably to a normal 4f6(7FJ)5d(t2g)→4f7(8S7/2) transition of Eu2+substituting the Sr2+sites. This can be justified by the presence of a fine structure in the excitation spectra due to the different7FJlevels (J=0⋯6) of the 4f6core. Moreover, Fano antiresonances with the6IJ(J=9/2,7/2) levels could be observed. In addition, the Stokes shifts (ΔES=1980 cm−1and 5 270 cm−1for the blue and green emission, resp.), the Huang-Rhys parameters ofS=2.5and 6, and the average phonon energies ofħω=480 cm-1and 470 cm−1coupled with the electronic states could be reliably determined.

White-Light-Emitting Phosphate Phosphors of SrZn2(PO4)2: Eu2+, Mn2+ Synthesized through Combustion Process

2011 ◽  
Vol 688 ◽  
pp. 344-348
Author(s):  
Xiao Song Yan ◽  
Wan Wan Li ◽  
Kang Sun
Keyword(s):  
Emission Band ◽  
Combustion Process ◽  
Blue Emission ◽  
Green Emission ◽  
Mixture Ratio ◽  
Blue Emission Band ◽  
Light Emitting ◽  
Green Emission Band ◽  
Emission Color ◽  
Emission Light

The SrZn2(PO4)2: Eu2+, Mn2+ phosphors were synthesized through combustion process with varying mixture ratio of Eu2+, Mn2+. The SrZn2(PO4)2: Eu2+, Mn2+ phosphor presents three emission bands under 365nm radiation: the blue emission band of 416 nm from Eu2+ occupying the Sr2+ site, the green emission band of 538 nm and the red emission band of 630 nm from Mn2+ occupying two different Zn2+ sites. Compared with the SrZn2(PO4)2: Eu2+, Mn2+ phosphor prepared through solid state reaction, the luminous intensity of the phosphor is greatly improved through the combustion reaction. White emission light with a high color rending index of 84.7 can be obtained from the phosphor of SrZn2(PO4)2: Eu2+, Mn2+, and the emission color tone of the phosphor varies from blue, white, and finally yellow by increasing the ratio of the concentrations of Eu2+ and Mn2+.

scholarly journals Emission Spectra of Crystal Phosphor BaCl2-Pb

1980 ◽  
Vol 35 (3) ◽  
pp. 308-311 ◽  
Author(s):  
Veneta Tabakova ◽  
Kyncho Kynev
Keyword(s):  
Emission Band ◽  
Emission Spectra ◽  
Barium Chloride ◽  
High Energy ◽  
Low Energy ◽  
Complex Nature ◽  
Excitation Spectra ◽  
Energy Emission ◽  
High Energy Emission ◽  
Effective Excitation

Abstract Emission spectra of Pb2+ centres in barium chloride single crystals have been studied between 4 and 300 K by excitation with different wave lengths. Excitation spectra at 300 K have also been obtained by measuring the emission in the maxima of the shoitwave and longwave bands. The results allow to conclude that the high energy emission band is due to the transition | 3T1u > → | 1A1g > in the activator ion. The more effective excitation of the low energy emission band observed in the shortwave region of the absorption spectrum and the complex nature of both bands are discussed.

Exciton-phonon interactions observed in blue emission band in Te-delta-doped ZnSe

2008 ◽  
Vol 104 (3) ◽  
pp. 033531 ◽  
Author(s):  
M. Jo ◽  
Y. Hayashi ◽  
H. Kumano ◽  
I. Suemune
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Blue Emission Band

Luminescence of SrY2O4:Eu3+ associated with defects

2010 ◽  
Vol 25 (11) ◽  
pp. 2120-2124 ◽  
Author(s):  
Jia Zhang ◽  
Yuhua Wang
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Vacuum Ultraviolet ◽  
Sol Gel ◽  
Blue Emission ◽  
Solid State Reaction Method ◽  
Excitation Spectra ◽  
Blue Emission Band ◽  
Gel Method ◽  
Sol Gel Method

SrY2O4:Eu3+ phosphors were synthesized by both the solid-state reaction method and the sol-gel method, and their photoluminescence in vacuum ultraviolet (VUV) and the ultraviolet (UV) region were evaluated. The excitation spectra of SrY2O4:Eu3+ phosphors prepared by solid-state reaction show another excitation band centered at 324 nm except for the charge-transfer bands (CTB) of Eu3+ when monitored at 610 nm, and a blue emission band around 406 nm is observed when excited at 324 nm, which could be associated with defects. Both the excitation and emission bands mentioned above disappear when the samples were prepared by the sol-gel method. SrY1.98O4:0.02Eu3+ phosphors synthesized by the sol-gel method exhibit a higher emission intensity under 147 nm excitation compared with solid-state reaction technology. The main reason could be that the samples prepared by the solution-based route have more regular and uniform morphologies.

Photoluminescence Properties and Energy Transfer in a Novel Yellow Emitting Phosphor GdTaO4:Dy3+

2016 ◽  
Vol 16 (4) ◽  
pp. 3994-3997 ◽  
Author(s):  
Huijuan Zhang ◽  
Xinyu Tan ◽  
Yuhua Wang
Keyword(s):  
Energy Transfer ◽  
Vacuum Ultraviolet ◽  
Emission Spectra ◽  
Host Lattice ◽  
Excitation Spectra ◽  
Light Emitting ◽  
Ultraviolet Excitation ◽  
Plasma Display Panels ◽  
Chromaticity Coordinates ◽  
Plasma Display

The phosphor Dy3+ doped M type gadolinium orthotantalate GdTaO4 was prepared successfully by traditional solid state reaction and the photoluminescence of GdTaO4: xDy3+ (0.01 ≤ x ≤ 0.10) has been investigated under ultraviolet and vacuum ultraviolet excitation. In the excitation spectra of GdTaO4:Dy3+, the overlap appears between the host lattice excitation, the excitation lines of Gd3+ and the f–f transitions of Dy3+, which indicates that the energy transfer could occur from the host to the Dy3+ ions. In the emission spectra of the samples, the intense emissions of Dy3+ have been expectably revealed both upon excitation at 365 nm and 147 nm. And the chromaticity coordinates of GdTaO4: xDy3+ have been correspondingly calculated. The results indicate that GdTaO4:Dy3+ would be a novel yellow emitting phosphor applied in light emitting diodes (LEDs), plasma display panels (PDPs) and mercury-free fluorescent tubes.

Zur Bildung und Umwandlung der „blauen“ und „grünen“ Zentren im goldaktivierten Zinksulfid / On the Formation and Conversion of “Blue” and “Green” Centres in Gold-Activated Zinc Sulphide

1979 ◽  
Vol 34 (2) ◽  
pp. 262-264 ◽  
Author(s):  
K. Kynev ◽  
V. Kuk
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Zinc Sulphide ◽  
Blue Emission Band ◽  
Gas Atmosphere

Abstract The phosphor ZnS-Au activated in the presence of zinc exhibits a blue emission band (Emax = 2,58 eV) which can be ascribed to associated Au′Zn-Vׄs-centres. A reversible interconversion of “blue” and “green” centres is achieved by retiring the phosphor samples in a suitable gas atmosphere

Effect of Microwave Irradiation Synthesis of ZnO Nanoparticles

2016 ◽  
Vol 19 (1) ◽  
pp. 021-026 ◽  
Author(s):  
Chelladurai Amutha ◽  
Balan Natarajan ◽  
Sethuramachandran Thanikaikarasan ◽  
Adaikalam Cyrac Peter ◽  
Thaiyan Mahalingam ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Emission Band ◽  
Blue Emission ◽  
Hexagonal Structure ◽  
X Rays ◽  
X Ray Diffraction ◽  
Ultraviolet Emission ◽  
Blue Emission Band ◽  
Diffraction Patterns ◽  
Bending Modes

Zinc Oxide nanoparticles were synthesized from zinc acetate by microwave irradiation method. X-ray diffraction patterns showed that the prepared samples found to exhibit hexagonal structure. Surface morphology and presence of elements have been analyzed using scanning electron microscopy and energy dispersive analysis by X-rays. The presence of stretching and bending modes in the prepared samples has been determined using Fourier transform infrared spectroscopy. Optical absorption analysis showed that the prepared samples possess band gap value around 3.02 eV. Photoluminescence spectroscopic analysis indicated a strong ultraviolet emission band at 390 nm and a weak blue - green band and weak blue emission band at 484 and 444 nm respectively.

Blue emission band in compensated GaN:Mg codoped with Si

2003 ◽  
Vol 68 (4) ◽  
Author(s):  
B. Han ◽  
J. M. Gregie ◽  
B. W. Wessels
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Blue Emission Band

A New Salt-Inclusion Single-Phased White Phosphor Ba7B3SiO13Br:Dy3+ for White Light-Emitting Diodes

2019 ◽  
Vol 803 ◽  
pp. 93-97
Author(s):  
Hai Dong Ju ◽  
Bao Ling Wang ◽  
Qi Mei Yang
Keyword(s):  
White Light ◽  
Emission Band ◽  
Light Emitting Diodes ◽  
Hexagonal Phase ◽  
Blue Emission ◽  
Yellow Emission ◽  
Conventional Solid State Reaction ◽  
Blue Emission Band ◽  
Light Emitting ◽  
White Light Emitting Diodes

A series of Ba7B3SiO13Br:Dy3+ phosphors were synthesized by a conventional solid-state reaction method for the first time. The X-ray diffraction patterns confirmed that the samples were pure phase and crystallized in a hexagonal phase with a space group of the P63mc (186). The luminescence spectrum exhibited a strong blue emission band peaked at 478 nm, a strong yellow emission band at 575 nm and a weak emission band at 665 nm, corresponding to the transitions from 4F9/2 to 6H15/2, 6H13/2 and 6H13/2 of Dy3+, respectively. According to the emission spectrum of Ba6.92B3SiO13Br:0.08Dy3+ excited at 349 nm, the chromaticity coordinate was calculated to be (0.317, 0.358) located on the white light region. The concentration quenching mechanism of Dy3+ in Ba7B3SiO13Br was ascribed to the multipolar-multipolar interaction. The current researches suggested that the phosphor can be used as a white phosphor suitable for white light-emitting diodes.

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