Synthesis and Optical Characterization of M-α-Sialon (M=Ca, Ba, Sr) Doped by Europium

2014 ◽  
Vol 90 ◽  
pp. 141-148
Author(s):  
Daniel Michalik ◽  
Tomasz Pawlik ◽  
Malgorzata Sopicka-Lizer ◽  
Radosław Lisiecki
Keyword(s):  
Chemical Resistance ◽  
Solid State Reaction Method ◽  
Rare Earth Ions ◽  
Color Temperature ◽  
Broad Emission Band ◽  
White Led ◽  
Photoluminescence Properties ◽  
Synthesis Parameters ◽  
Broad Emission

Oxynitrides compounds are interesting for white LED industry because more covalent matrix's bonds in comparison to oxides enable to obtain higher color temperature of wLED. The Sialon's luminescence material doped by rare earth ions with high mechanical and chemical resistance and a broad emission band may become an alternative for garnet phosphors. The goal of the study was to investigate influence of divalent stabilizing cations on luminescence properties of M-α-Sialon doped with Eu2+in order to estimate its potential for YAG:Ce replacement in WLEDs. The compound of general formula EuxM1-xSi9,6Al2,4O0,8N15,2, where M=Ca, Ba, Sr, was prepared by the solid state reaction method from the mixture of the relevant oxides, nitrides and carbonates. Synthesis was carried out at the temperature of 1650°C for 4 h in a reduction atmosphere (N2+CO). The structure and morphology of obtained powders were analyzed by XRD and SEM/EDS methods, respectively. Optical properties were investigated by excitation, emission and reflection spectra and compared to photoluminescence properties of standard YAG:Ce. The obtained specimens show the significant effect of synthesis parameters on the phase composition and intensity of emission of M-α-Sialon:Eu2+powder.

Synthesis and Luminescent Properties of Violet-Ultraviolet Long Afterglow Phosphors

2010 ◽  
Vol 663-665 ◽  
pp. 170-176
Author(s):  
Hao Yi Wu ◽  
Yi Hua Hu ◽  
Yin Hai Wang ◽  
Chu Jun Fu ◽  
Feng Wen Kang ◽  
...  
Keyword(s):  
Solid State ◽  
Oxygen Vacancies ◽  
Trap Depth ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Broad Emission Band ◽  
Suitable Model ◽  
Reaction Method ◽  
Long Afterglow ◽  
Broad Emission

The M1.99MgSi2O7: Ce3+0.01 (M: Ba, Sr, Ca) phosphors were prepared by the solid-state reaction method. All the samples emit the violet-ultraviolet light with a broad emission band from about 330 nm to 500 nm. All the phosphors samples show a long afterglow. The strongest afterglow intensity and the longest decay duration of the afterglow come from the Ca1.99MgSi2O7: Ce3+0.01 sample. It is attributed to the suitable trap depth and the high trap concentration of this sample. The traps of these phosphors are induced by the lattice defects. A suitable model involving the cation vacancies and the oxygen vacancies, which act as the hole traps and the electron traps respectively, is proposed.

scholarly journals Yellow Emission Obtained by Combination of Broadband Emission and Multi-Peak Emission in Garnet Structure Na2YMg2V3O12: Dy3+ Phosphor

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 542 ◽  
Author(s):  
Weiyi Zhang ◽  
Can He ◽  
Xiaowen Wu ◽  
Ximing Huang ◽  
Fankai Lin ◽  
...  
Keyword(s):  
Solid State ◽  
White Light ◽  
Emission Band ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Color Temperature ◽  
Broad Emission Band ◽  
Yellow Emission ◽  
Conventional Solid State Reaction ◽  
Broad Emission

The fabrication and luminescent performance of novel phosphors Na2YMg2V3O12:Dy3+ were investigated by a conventional solid-state reaction method. Under near-UV light, the Na2YMg2V3O12 host self-activated and released a broad emission band (400–700 nm, with a peak at 524 nm) ascribable to charge transfer in the (VO4)3− groups. Meanwhile, the Na2YMg2V3O12:Dy3+ phosphors emitted bright yellow light within both the broad emission band of the (VO4)3- groups and the sharp peaks of the Dy3+ ions at 490, 582, and 663 nm at a quenching concentration of 0.03 mol. The emission of the as-prepared Na2YMg2V3O12:Dy3+ phosphors remained stable at high temperatures. The obtained phosphors, commercial Y2O3:Eu3+ red phosphors, and BaMgAl10O17:Eu2+ blue phosphors were packed into a white light-emitting diode (WLED) device with a near-UV chip. The designed WLED emitted bright white light with good chromaticity coordinates (0.331, 0.361), satisfactory color rendering index (80.2), and proper correlation to a color temperature (7364 K). These results indicate the potential utility of Na2YMg2V3O12:Dy3+ phosphor as a yellow-emitting phosphor in solid-state illumination.

SYNTHESIS AND CHARACTERIZATION OF FLUORESCENT Cu2S NANOPARTICLES EMBEDDED IN AMORPHOUS POLYSTYRENE

2010 ◽  
Vol 09 (05) ◽  
pp. 385-389 ◽  
Author(s):  
G. CAROTENUTO ◽  
F. CAPEZZUTO ◽  
M. PALOMBA ◽  
F. NICOLAIS
Keyword(s):  
Thermal Decomposition ◽  
Synthesis And Characterization ◽  
Broad Emission Band ◽  
Trap State ◽  
Broad Emission ◽  
Time Period ◽  
Polystyrene Matrix ◽  
Red Luminescence ◽  
Quenching Phenomenon

Very small Cu2S nanoparticles have been generated inside an amorphous polystyrene matrix by thermal decomposition of Cu(I) mercaptide molecules dissolved in the polymer. The resulting nanocomposite material was transparent, yellow colored, and characterized by a quite strong red luminescence. In particular, the sample photoluminescence (PL) spectrum showed three excitation wavelengths and a quite broad emission band resulting from the combination of band-edge and trap-state emission. However, luminescence was not stable over the time and a quenching phenomenon was observed after a time period of ca. three months.

Photoluminescence properties of Pr3+, Sm3+ and Tb3+ doped SrAlSi4N7 and energy level locations of rare-earth ions in SrAlSi4N7

2014 ◽  
Vol 2 (37) ◽  
pp. 7952-7959 ◽  
Author(s):  
Zhi-Jun Zhang ◽  
Otmar M. ten Kate ◽  
Anneke Delsing ◽  
Pieter Dorenbos ◽  
Jing-Tai Zhao ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Solid State ◽  
Energy Level ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Rare Earth Ions ◽  
Photoluminescence Properties ◽  
Reaction Method

RE3+ (RE = Pr, Sm, and Tb)-doped SrAlSi4N7 samples were synthesized by a solid-state reaction method at high temperature, and their photoluminescence properties were investigated.

scholarly journals Developments of crystal structures and photoluminescence properties of Sr0.85Eu0.15Al12O19 green phosphors using different synthesis parameters

2021 ◽  
Author(s):  
Jie Li ◽  
Qing-Hao Yang ◽  
Hsin-Hua Li ◽  
Cheng-Fu Yang ◽  
David Jui-Yang Feng
Keyword(s):  
Crystal Structures ◽  
Solid State Reaction Method ◽  
Synthesis Temperature ◽  
Emission Peak ◽  
Photoluminescence Excitation ◽  
Photoluminescence Properties ◽  
Apparent Effect ◽  
Reaction Method ◽  
Pl Spectra ◽  
Synthesis Parameters

First, a solid-state reaction method was used to synthesize a [Formula: see text] phosphor at 1250[Formula: see text]C–1400[Formula: see text]C for 1 h, and its crystal structures and photoluminescence properties were investigated as a function of synthesis temperature. When the furnace reached the synthesis temperature, the 5% [Formula: see text] reduction atmosphere was infused and the reduction atmosphere was removed as the temperature was dropped to 800[Formula: see text]C. When 1200[Formula: see text]C was used as the synthesis temperature, the [Formula: see text], [Formula: see text], and [Formula: see text] phases co-existed; only one weak emission peak was observed in the photoluminescence excitation (PLE) spectra, and two weak emission peaks were observed in the photoluminescence emission (PL) spectra. When the [Formula: see text] phosphors were synthesized at a temperature higher than 1200[Formula: see text]C, the diffraction intensities of [Formula: see text], [Formula: see text], and [Formula: see text] phases were almost unchanged, but the crystal sizes of [Formula: see text] powders increased. For [Formula: see text] phosphors, PLE spectra had one broad exciting band with two centered wavelengths of 317 and 365 nm, and PL spectra had one emission band with one centered wavelength of 513 nm. As the synthesis temperature rose, the emission intensities of PLE and PL spectra increased. Second, we show that the removed temperature of reduction atmosphere of [Formula: see text] phosphors had an apparent effect on their emission properties of PLE and PL spectra.

Compatibility of Photoluminescence Properties in ScPO4:Eu3+, Tb3+ Phosphor for White Light Emitting Diodes

2021 ◽  
Vol 21 (12) ◽  
pp. 5890-5895
Author(s):  
Jian Zhou ◽  
Jian-Wen Zhao ◽  
Si-Li Ren ◽  
Jun Dong
Keyword(s):  
The Body ◽  
Color Temperature ◽  
White Led ◽  
Photoluminescence Properties ◽  
Light Emitting ◽  
Co Doping ◽  
Emission Color ◽  
Single Matrix ◽  
White Light Emitting Diodes ◽  
Color Rendering

ScPO4:Eu3+, Tb3+ phosphors with tuned emission color were prepared through high temperature solid-state reaction. The structure, morphology and photoluminescence properties of the title samples were collected by XRD, SEM and fluorescence spectrophotometer, respectively. Co-doping Eu3+ and Tb3+ in ScPO4 does not change the body-centered tetragonal structure of the host. And the morphology remains essentially unchanged except for slight agglomeration. Changing the ratio of Tb3+/Eu3+, the tuned emission can be achieved, the color could be adjusted from green through yellow to orange-red. The ScPO4:0.03Tb3+, 0.03Eu3+ phosphor with high thermal stability as the single matrix phosphor can be suitable for the NUV-pumped white LED. The white LED with a color rendering index of 86.5 and a correlated color temperature of 3470 K has been generated by packaging BAM:Eu2+ with ScPO4:0.03Tb3+, 0.03Eu3+ on an NUV-InGaN chip.

Characterization of B-Implanted 3C-SiC for Intermediate Band Solar Cells

2017 ◽  
Vol 897 ◽  
pp. 299-302
Author(s):  
Quan Bao Ma ◽  
Patricia Almeida Carvalho ◽  
Augustinas Galeckas ◽  
Alexander Azarov ◽  
Sigurd Hovden ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Broad Emission Band ◽  
Plateau Region ◽  
Emission Pattern ◽  
Intermediate Band ◽  
Intermediate Band Solar Cells ◽  
Broad Emission ◽  
Sims Analysis ◽  
Pl Emission

Sublimation-grown 3C-SiC crystals were implanted with B ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 1.3×1017 atoms/cm2 in order to form intermediate band (IB) in 3C-SiC. The samples were then annealed at 1400 °C for 60 min. An anomalous area in the center was observed in the PL emission pattern. The SIMS analysis indicated that the B concentration was the same both within and outside the anomalous area. The buried boron box-like concentration profile can reach ~3×1021 cm-3 in the plateau region. In the anomalous area a broad emission band (possible IB) emerges at around ~1.7-1.8 eV, which may be associated with B-precipitates having a sufficiently high density.

scholarly journals MoS2@ZnO Nanoheterostructures Prepared by Electrospark Erosion for Photocatalytic Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 157
Author(s):  
Vladimir An ◽  
Herman Potgieter ◽  
Natalia Usoltseva ◽  
Damir Valiev ◽  
Sergei Stepanov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Broad Emission Band ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broad Emission ◽  
Transmission Electron ◽  
Photocatalytic Applications

MoS2@ZnO nanoheterostructures were synthesized by electrospark erosion of zinc granules in a hydrogen peroxide solution and simultaneous addition of MoS2 nanostructured powder into the reaction zone. The morphology, size of the crystallites, as well as elemental and phase composition of the prepared structures, were examined using transmission electron microscopy and X-ray diffraction analysis. It was found that the synthesized products represent heterostructures containing MoS2 nanoparticles formed on ZnO nanoparticles. Raman spectroscopy and photoluminescence analysis were also used for characterization of the prepared heterostructures. The obtained MoS2@ZnO nanostructures revealed an intense broad emission band ranging from 425 to 625 nm for samples with different fractions of MoS2. Photocatalytic measurements showed that the maximal hydrogen evolution rate of the prepared nanoheterostructures was about 906.6 μmolg−1h−1.The potential of their application in photocatalytic water splitting was also estimated.

Simulation of Temperature Induced Colorimetric Shift of YAG:Ce0.06,GDx Phosphor

2011 ◽  
Vol 55-57 ◽  
pp. 675-679
Author(s):  
Ting Ji ◽  
Xiao Song Zhang ◽  
Qun Xi
Keyword(s):  
Color Temperature ◽  
Broad Emission Band ◽  
Concentration Increase ◽  
Solid State Method ◽  
Clear Trend ◽  
Chromaticity Coordinate ◽  
Broad Emission ◽  
Chromaticity Coordinates ◽  
State Method ◽  
Increasing Temperature

YAG:Ce0.06,Gdxphosphors were prepared by solid-state method, and temperature dependence of chromaticity coordinate and correlated color temperature of YAG:Ce0.06,Gdxare investigated. Three PL spectra all have broad emission band between 500 nm and 620 nm is assigned to the combination of the lowest energy of 5d bands and the2F5/2and2F7/2states respectively. With increasing temperature, the x values of chromaticity coordinates of YAG:Ce0.06,Gdxwith Gd concentration increase all increase, but y values all decrease. Differently, z values do not show a clear trend. Moreover, correlated color temperature of YAG:Ce0.06,Gdxwith Gd concentration increase all decrease with the temperature increase.

LUMINESCENT PROPERTIES OF Sr3B2O6: Eu2+ YELLOW-EMITTING PHOSPHOR FOR WHITE LIGHT-EMITTING DIODES

2013 ◽  
Vol 06 (01) ◽  
pp. 1350009 ◽  
Author(s):  
QUAN-SHENG LIU ◽  
TIAN CUI ◽  
XI-YAN ZHANG ◽  
YUE SONG
Keyword(s):  
Wide Band ◽  
Luminescent Properties ◽  
Color Temperature ◽  
Broad Emission Band ◽  
Band Spectrum ◽  
White Led ◽  
Solid State Method ◽  
Light Emitting ◽  
Yellow Phosphor ◽  
Cie Chromaticity

Eu2+ doped Sr3B2O6 yellow phosphor for warm white LED was synthesized by high temperature solid-state method. The structure and optical properties of Sr3B2O6 : Eu2+ were studied. Results indicate that Sr3B2O6 : Eu2+ has a rhombohedral crystalline structure. The excitation spectrum of phosphor is a wide-band spectrum mainly peaking at 469 nm, which is suitable for GaN -based blue light LED excitation. The luminescent spectrum of phosphor exhibits a broad emission band centered at 566 nm, corresponding to the typical 4f65d1–4f7 transition of Eu2+ . Guass fitting shows the main emission peak is at 575 nm, which is identical with the dominant wavelength of the yellow phosphor. The CIE chromaticity coordinate of white LED is (x = 0.389, y = 0.419). The LED reveals warm tone and the relevant color temperature of that is 4044 K. The luminescent efficiency of White LED reaches 18l m/W, which is higher than reported.

Sign in / Sign up

Export Citation Format

Share Document