Effect of Molten Salts on Synthesis and Upconversion Luminescence of Ytterbium and Thulium-Doped Alkaline Yttrium Fluorides

2018 ◽  
Vol 766 ◽  
pp. 34-39 ◽  
Author(s):  
Thanataon Pornpatdetaudom ◽  
Karn Serivalsatit
Keyword(s):  
Visible Light ◽  
Molten Salt ◽  
Ultraviolet Light ◽  
Laser Diode ◽  
Molten Salts ◽  
Upconversion Luminescence ◽  
The Other ◽  
Ultraviolet Region ◽  
Molten Salt Method ◽  
Lower Intensity

Upconversion luminescence materials have recently received attentions because of theirs light conversion ability from infrared into visible and ultraviolet light. In this work, alkaline yttrium fluoride doped by ytterbium and thulium (AYF4: 20%Yb3+, 0.5%Tm3+) were synthesized by molten salt method at 400 °C for 2 hours with different eutectic molten salts, i.e. NaNO3-KNO3, NaNO3-LiNO3, KNO3-LiNO3, and NaNO3-KNO3-LiNO3. Pure hexagonal NaYF4 microrods were successfully synthesized using eutectic NaNO3-KNO3 molten salt. Under 980 nm laser diode excitation, upconversion luminescence in both visible and ultraviolet region was clearly observed. On the other hand, for the use of other eutectic molten salts containing LiNO3, the mixed phases of tetragonal LiYF4 and orthorhombic Y6O5F8 were obtained. These powders emitted only visible light with 10 times lower intensity than the hexagonal NaYF4 microrods synthesized using NaNO3-KNO3.

MOLTEN SALT SYNTHESIS OF YF3:Yb3+/Ln3+(Ln = Er3+, Tm3+) MICROSHEETS WITH MULTICOLOR UPCONVERSION LUMINESCENCE

2013 ◽  
Vol 06 (06) ◽  
pp. 1350061 ◽  
Author(s):  
MINGYE DING ◽  
CHUNHUA LU ◽  
LINHAI CAO ◽  
YARU NI ◽  
ZHONGZI XU
Keyword(s):  
Molten Salt ◽  
Laser Diode ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Upconversion Emission ◽  
Molten Salt Synthesis ◽  
Molten Salt Method ◽  
Orthorhombic System ◽  
Co Doping ◽  
First Time

In this paper, highly crystalline YF 3: Yb 3+/ Ln 3+( Ln = Er 3+, Tm 3+) microsheets were successfully synthesized by a surfactant-free molten salt method for the first time. The results indicated that the as-obtained samples belonged to orthorhombic system and exhibited microsheets morphology with side lengths of 30 to 80 μm and wall thickness from 1 to 1.5 μm. By changing the dopant's species ( Ln 3+), multicolor (yellow and blue) upconversion emission can be observed in YF 3: Yb 3+/ Ln 3+ microsheets under 980 nm laser diode (LD) excitation. The upconversion mechanisms in co-doping YF 3 samples were analyzed in detail based on the emission spectra. Importantly, this approach not only proposes a new alternative in synthesizing such materials, but also opens the possibility to meet the increasing commercial demand.

scholarly journals Facile preparation of ZrO2 whiskers by LiF-KCl molten salts synthesis

2021 ◽  
Vol 15 (3) ◽  
pp. 219-225
Author(s):  
Quan Zhang ◽  
Guo Feng ◽  
Feng Jiang ◽  
Jianmin Liu ◽  
Lifeng Miao ◽  
...  
Keyword(s):  
Molten Salt ◽  
Lithium Fluoride ◽  
Slow Rate ◽  
Molten Salts ◽  
Treatment Temperature ◽  
Molten Salt Method ◽  
Monoclinic Zirconia ◽  
Zirconyl Chloride ◽  
Aspect Ratios ◽  
Dissolution And Precipitation

Monoclinic zirconia (ZrO2) whiskers were made via the molten salt method using zirconyl chloride octahydrate (ZrOCl2 ? 8H2O) as zirconium source, potassium chloride (KCl) as molten salt and lithium fluoride (LiF) as a mineraliser. DSC-TG, XRD, FE-SEM, Raman and TEM were performed to study the effects of heat treatment temperature, holding time and heating rate on the synthesis of zirconia whiskers. The results indicate that zirconia whiskers with diameters of 50-80 nm and aspect ratios of 10-30 can be obtained by heating the precursor at slow rate (3?C/min) to 718?C for 1 h and then at faster rate (7?C/min) to 950?C for 3 h. The whiskers have a smooth surface and grow in [001] direction. The key to the ZrO2 whiskers growth is the controlled dissolution and precipitation of the ZrO2 in a LiF-KCl molten salt solution environment.

Synthesis of Pure Bi12SiO20 Powder by Molten Salt Method

2012 ◽  
Vol 182-183 ◽  
pp. 52-56
Author(s):  
Jun Que Lu ◽  
Xiu Feng Wang ◽  
Hong Tao Jiang
Keyword(s):  
Particle Size ◽  
Molten Salt ◽  
Molten Salts ◽  
Raw Materials ◽  
Reaction Medium ◽  
Processing Parameters ◽  
Molten Salt Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pure Phase

Pure Bi12SiO20powder was successfully prepared by a molten salt method using Bi2O3and SiO2as raw materials and using KCl-K2CO3as flux at 635°C with the heating rate of 5°Cmin-1. The phase composition and microstructure of these products were analyzed by X-ray diffraction and scanning electron microscopy, and the effects of the processing parameters, such as the ratio of Bi2O3/SiO2, calciniation temperature, isothermal time and relative amount of salt, on the composition and particle size were investigated. The results indicated that regardless of changing the ratio of Bi2O3/SiO2, calciniation temperature, isothermal time or relative amount of salt the reaction only yielded Bi12SiO20without Bi2SiO5and Bi4Si3O12. Henceforth, KCl-K2CO3molten salts may be considered as an ideal reaction medium to synthesize pure phase of Bi12SiO20. The particle size of Bi12SiO20phase can be determined by changing the temperature, isothermal time and relative amount of salt.

Development of Porous Materials Using Sewage Sludge by Molten-Salt Method

2008 ◽  
Vol 569 ◽  
pp. 325-328
Author(s):  
Yeong Seok Yoo ◽  
Kyeong Ho Cheon ◽  
Jae Ik Lee ◽  
Beom Suk Kim ◽  
Woo Seob Shin ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Porous Material ◽  
Molten Salt ◽  
Surface Area ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
The Other ◽  
Artificial Soil ◽  
Molten Salt Method ◽  
Area Distribution

This study is about the development of porous material which shapes Ø3~8mm bead with sewage sludge by molten-salt method. The development of porous material was conducted by 2 different processes. One is made by molding sewage sludge into beads with pelletizer and then coating the beads with molten-salt and lastly sintered at 1050°C, and the other is mixing sewage sludge with molten-salt which is using synthesized zeolite, and then molding the mixture into beads with pelletizer. The molded mixture is finally sintered at 1050°C. We evaluated the value of developed material as sorbent and artificial soil for tree-planning by analyzing surface area, distribution of pore size, and cation exchange capacity(CEC). According to the results, surface coated porous material have 92.8m2/g of surface area and CEC 98.9meq/100g and the mixture sewage sludge with molten-salt have 104.1m2/g of surface area and CEC 140.8meq/100g. Thus, developed porous material can be applied to various uses as sorbent and artificial soil.

Sintering of Ba1-XSrXTiO3 Powders Prepared Using KOH-KNO3 Molten Salt Method

2009 ◽  
Vol 421-422 ◽  
pp. 235-238 ◽  
Author(s):  
Tomohiko Kishiki ◽  
Masashi Higuchi ◽  
Takashi Asaka ◽  
Yasuo Azuma ◽  
Keiichi Katayama
Keyword(s):  
Electrical Properties ◽  
Molten Salt ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Molten Salts ◽  
Sintering Behavior ◽  
Molten Salt Method ◽  
Barium Strontium ◽  
Perovskite Type ◽  
Perovskite Type Structure

Barium strontium titanate (BST), which has a typical perovskite-type structure, shows excellent electrical properties. BST powders were synthesized by heating mixtures of commercial reagents with an excess of TiO2 in molten salts of KOH and KNO3, and the sintering behavior of the resulting powders was evaluated. The sample with the highest density of 95% was obtained by sintering of the BST powders.

Effect of Frit Material on External Transport Numbers in Molten Salts

1982 ◽  
Vol 37 (7) ◽  
pp. 706-709 ◽  
Author(s):  
Carl-Axel Sjöblom ◽  
Richard W. Laity
Keyword(s):  
Boron Nitride ◽  
Temperature Dependence ◽  
Molten Salt ◽  
Porous Glass ◽  
Interfacial Layer ◽  
Experimental Error ◽  
Molten Salts ◽  
The Other ◽  
Transport Numbers ◽  
Measuring Techniques

Abstract Molten salt external transport numbers have been examined with respect to the possible in-fluence of the frit material. Improved measuring techniques revealed a slight temperature dependence for the transference of PbCl2 in Pyrex frits over the range 529 to 610°C, but generally con-firmed the values obtained by most of the earlier workers who used porous glass or related mate-rials. Within experimental error the figures were found to be identical in Pyrex frits of two different pore sizes. On the other hand, significant deviations were detected when a boron nitride frit was used. These experiments confirm that the transport properties of the interfacial layer between the melt and the solid depend on the nature of the solid.

scholarly journals Fabrication and Evaluation of Visible Light Active TiO2 Photocatalyst by Molten Salt Method

2013 ◽  
Vol 77 (7) ◽  
pp. 287-293 ◽  
Author(s):  
Yutaka Hirakawa ◽  
Yun Lu ◽  
Hiroyuki Yoshida ◽  
Koh Matsuzaka ◽  
Liang Hao ◽  
...  
Keyword(s):  
Visible Light ◽  
Molten Salt ◽  
Molten Salt Method ◽  
Tio2 Photocatalyst ◽  
Visible Light Active

Visible-Light-Mediated Organoboron-Catalysed Metal-Free Dehydrogenation of N-Heterocycles Using Molecular Oxygen

2021 ◽  
Author(s):  
Lanfeng Wei ◽  
Yu Wei ◽  
Jinli Zhang ◽  
Liang Xu
Keyword(s):  
Visible Light ◽  
Molecular Oxygen ◽  
The Other ◽  
Metal Free ◽  
Other Hand

The surge of photocatalytic transformation not only provides unprecedented synthetical methods, but also triggers the enthusiasm for more sustainable photocatalysts. On the other hand, oxygen is an ideal oxidant in...

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