Effects of Various Fluxes on Synthesis of Deep Red Emitting CaAl12O19:Mn4+ Phosphors

2016 ◽  
Vol 852 ◽  
pp. 454-460 ◽  
Author(s):  
Qiu Hong Zhang ◽  
Hai Yong Ni ◽  
Ling Li Wang ◽  
Fang Ming Xiao
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Luminescent Intensity ◽  
Reaction Method ◽  
Structure Morphology ◽  
Forming Temperature

Deep red emitting CaAl12-xO19:xMn4+ phosphors were synthesized by solid state reaction method. Various fluxes (BaF2, H3BO3, Na2CO3 and NH4Cl) were added in preparation of the phosphors. The influences of the various fluxes on the crystal structure, morphology and luminescent properties of CaAl12O19:Mn4+ phosphors were studied. The results show that the obtained phosphors with fluxes possessed better luminescent intensity than that of the phosphors without fluxes. The maximum luminescent intensities were found with the following order: H3BO3 (2.0 wt%) > Na2CO3 (0.5 wt%) > NH4Cl (0.3 wt%) > BaF2 (0.1 wt%) > no flux. The H3BO3 flux can decrease the single phase forming temperature of CaAl12O19:Mn4+ phosphors by about 150°C.

scholarly journals Thermoelectric Study of La2Ti2-xNbxO7 (0≤x≤0.25) Ceramic Materials

2020 ◽  
pp. 38-47
Author(s):  
A. C. Iyasara ◽  
F. U. Idu ◽  
E. O. Nwabineli ◽  
T. C. Azubuike ◽  
C. V. Arinze
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Solid State ◽  
Single Phase ◽  
Ceramic Materials ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Reducing Atmosphere ◽  
High Seebeck Coefficient ◽  
Porous Microstructures

La2Ti2-xNbxO7 (x = 0.00, 0.05, 0.10, 0.15, 0.20, 0.25) powders were synthesised via solid state reaction method, followed by sintering at 1673 K in a reducing atmosphere of 5% H2/N2 gas. The crystal structure, microstructure and thermoelectric (TE) properties of the pure and Nb-doped La2Ti2O7 ceramics were investigated. All compositions were single phase with porous microstructures consistent with their low experimental densities. Thermoelectric results of Nb-doped compositions showed improved properties in comparison to pure La2Ti2O7, suggesting that cation doping has the potential to improve the thermoelectric properties. Generally, the TE results obtained are not suitable for thermoelectric applications. However, the high Seebeck coefficient (≥190 μV/K) and glass-like thermal conductivity ( ≤2.26 w / m.k )  values achieved have opened a new window for exploring the thermoelectric potentials of La2Ti2O7 and other related oxides.

Thermal enhancement of 2H11/2→4I15/2 up-conversion luminescence of Er3+ doped K2Yb(PO4)(MoO4) phosphors

2021 ◽  
Author(s):  
Hongqiang Cui ◽  
Yongze Cao ◽  
Lei Zhang ◽  
Yuhang Zhang ◽  
Siying Ran ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Reaction Method ◽  
X Ray ◽  
Thermal Enhancement

Er3+ with different concentrations doped K2Yb(PO4)(MoO4) phosphors were prepared by a solid-state reaction method, and the layered orthorhombic crystal structure of the samples was confirmed by X-ray diffraction (XRD). Under...

scholarly journals Phonon characteristics, crystal structure, and intrinsic properties of a Y(Mg1/2Sn1/2)O3 ceramic

RSC Advances ◽  
2017 ◽  
Vol 7 (56) ◽  
pp. 35305-35310 ◽  
Author(s):  
Chao Xing ◽  
Jianzhu Li ◽  
Huiling Chen ◽  
Hengyang Qiao ◽  
Jun Yang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Intrinsic Properties ◽  
Conventional Solid State Reaction ◽  
Reaction Method

Herein, a Y(Mg1/2Sn1/2)O3 (YMS) ceramic was synthesized using a conventional solid-state reaction method.

Effects of Sm3+ Doping on the Photoluminescence Properties of Ca9Eu1-xSmx(VO4)7 Red-Emitting Phosphors

2012 ◽  
Vol 512-515 ◽  
pp. 1488-1493 ◽  
Author(s):  
Li Hong Liu ◽  
Rong Jun Xie ◽  
Xu Dong Sun ◽  
Qing Huang ◽  
Naoto Hirosaki
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Excitation Energy ◽  
Solid State Reaction ◽  
Emission Intensity ◽  
Solid State Reaction Method ◽  
Photoluminescence Properties ◽  
Reaction Method ◽  
White Leds ◽  
Uv Led

This paper reports the photoluminescence properties of Ca9Eu1-xSmx(VO4)7 (x=0.2-0.4) synthesized at 1250 oC in air for 12 h using traditional solid-state reaction method. With the increase of Sm3+ substitution amount, purity Ca9Eu1-xSmx(VO4)7 phase was obtained even when the Eu3+ ions were totally substituted by Sm3+. The experimental results showed that when Sm3+ was codoped with Eu3+ into Ca9Eu1-xSmx(VO4)7 crystal structure, Sm3+ would act as a sensitizer and transfer the excitation energy to Eu3+ ions and finally enhance the emission intensity of Ca9Eu1-xSmx(VO4)7 under 405 nm excitation, which leads to more favorite of this kind of phosphor used in UV LED based white LEDs.

Luminescence Properties of Self-Activated M3(VO4)2 (M = Mg, Ca, Sr, and Ba) Phosphors Synthesized by Solid-State Reaction Method

2016 ◽  
Vol 16 (4) ◽  
pp. 3684-3689 ◽  
Author(s):  
Xin Min ◽  
Zhaohui Huang ◽  
Minghao Fang ◽  
Yan’gai Liu ◽  
Chao Tang ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Uv Light ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Reaction Method ◽  
X Ray ◽  
Yield Decrease

In this paper, M3(VO4)2 (M = Mg, Ca, Sr, and Ba) self-activated phosphors were prepared by a solid-state reaction method at 1,000 °C for 5 h. The phase formation and micrographs were analyzed by X-ray diffraction and scanning electron microscopy. The Ca3(VO4)2 phosphor does not show any emission peaks under excitation with ultraviolet (UV) light. However, the M3(VO4)2 (M = Mg, Sr, and Ba) samples are effectively excited by UV light chips ranging from 200 nm to 400 nm and exhibit broad emission bands due to the charge transfer from the oxygen 2p orbital to the vacant 3d orbital of the vanadium in the VO4. The color of these phosphors changes from yellow to light blue via blue-green with increasing ionic radius from Mg to Sr to Ba. The luminescence lifetimes and quantum yield decrease with the increasing unit cell volume and V–V distance, in the order of Mg3(VO4)2 to Sr3(VO4)2 to Ba3(VO4)2. The emission intensity decreases with the increase of temperatures, but presents no color shift. This confirms that these self-activated M3(VO4)2 phosphors can be suggested as candidates of the single-phase phosphors for light using UV light emitting diodes (LEDs).

scholarly journals Synthesis and luminescent properties of novel red-emitting M7Sn(PO4)6:Eu3+(M= Sr,Ba) phosphors

2018 ◽  
Vol 12 (1) ◽  
pp. 8-12
Author(s):  
Guo Feng ◽  
Weihui Jiang ◽  
Jianmin Liu ◽  
Cong Li ◽  
Quan Zhang
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Red Light ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Formula Unit ◽  
Conventional Solid State Reaction ◽  
Light Emitting ◽  
Reaction Method ◽  
Uv Leds

Novel Eu3+-activated M7Sn(PO4)6 (where M = Sr, Ba) red-emitting phosphors were synthesized via conventional solid-state reaction method at 1200 ?C for 2 h. The luminescence properties of the prepared samples and quenching concentration of Sr7-xSn(PO4)6 :xEu3+ and Ba7-xSn(PO4)6 :xEu3+ were investigated. These phosphors can be efficiently excited by UV (395 nm) and visible blue (465 nm) light nicely matching the output wavelengths of the near-UV LEDs and InGaN blue LED chips and emit the red light. The critical concentrations of the Eu3+ activator were found to be 0.175mol and 0.21mol per formula unit for Sr7-xSn(PO4)6 :xEu3+ and Ba7-xSn(PO4)6 :xEu3+, respectively. The M7-xSn(PO4)6 :xEu3+ (M = Sr, Ba) phosphor may be a good candidate for light-emitting diodes application.

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