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Title: Dual preparation of hydrophobic and hydrophilic BaWO{sub 4}:Eu phosphors

Abstract

Highlights: • Red-emitting BaWO{sub 4}:Eu phosphors were prepared in hexane-water bilayer system. • The hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors were obtained in hexane. • The hydrophilic micrometer-sized BaWO{sub 4}:Eu dendrites were obtained in water. - Abstract: BaWO{sub 4}:Eu phosphors were prepared by performing a solvothermal reaction in a water–hexane bilayer system. A barium oleate (and europium oleate) complex was obtained in hexane via a phase transfer reaction involving Ba{sup 2+} (and Eu{sup 3+}) ions in an aqueous solution of sodium oleate. The outer surfaces of the nanometer-sized BaWO{sub 4}:Eu phosphors were capped by the long alkyl chain of oleate; therefore, the hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors preferentially dissolved in the hexane layer. The micrometer-sized BaWO{sub 4}:Eu phosphors were obtained in the water layer. The BaWO{sub 4}:Eu phosphors prepared in hexane and water yielded sharp strong absorption and emission peaks at 464 and 615 nm, respectively, due to the {sup 7}F{sub 0} → {sup 5}D{sub 2} and the {sup 5}D{sub 0} →{sup 7} F{sub 2} transitions of the Eu{sup 3+} ions. The BaWO{sub 4}:Eu phosphors are good candidate red-emitting phosphors for use in InGaN blue-emitting diodes, which have an emission wavelength of 465 nm.

Authors:
;
Publication Date:
OSTI Identifier:
22581556
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 78; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTRA; AQUEOUS SOLUTIONS; BARIUM IONS; BARIUM TUNGSTATES; EMISSION SPECTRA; EUROPIUM COMPOUNDS; EUROPIUM IONS; GALLIUM NITRIDES; HEXANE; INDIUM COMPOUNDS; LAYERS; PHOSPHORS; SODIUM COMPOUNDS; WATER

Citation Formats

Cho, Young-Sik, and Huh, Young-Duk, E-mail: ydhuh@dankook.ac.kr. Dual preparation of hydrophobic and hydrophilic BaWO{sub 4}:Eu phosphors. United States: N. p., 2016. Web. doi:10.1016/J.MATERRESBULL.2016.02.020.
Cho, Young-Sik, & Huh, Young-Duk, E-mail: ydhuh@dankook.ac.kr. Dual preparation of hydrophobic and hydrophilic BaWO{sub 4}:Eu phosphors. United States. doi:10.1016/J.MATERRESBULL.2016.02.020.
Cho, Young-Sik, and Huh, Young-Duk, E-mail: ydhuh@dankook.ac.kr. 2016. "Dual preparation of hydrophobic and hydrophilic BaWO{sub 4}:Eu phosphors". United States. doi:10.1016/J.MATERRESBULL.2016.02.020.
@article{osti_22581556,
title = {Dual preparation of hydrophobic and hydrophilic BaWO{sub 4}:Eu phosphors},
author = {Cho, Young-Sik and Huh, Young-Duk, E-mail: ydhuh@dankook.ac.kr},
abstractNote = {Highlights: • Red-emitting BaWO{sub 4}:Eu phosphors were prepared in hexane-water bilayer system. • The hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors were obtained in hexane. • The hydrophilic micrometer-sized BaWO{sub 4}:Eu dendrites were obtained in water. - Abstract: BaWO{sub 4}:Eu phosphors were prepared by performing a solvothermal reaction in a water–hexane bilayer system. A barium oleate (and europium oleate) complex was obtained in hexane via a phase transfer reaction involving Ba{sup 2+} (and Eu{sup 3+}) ions in an aqueous solution of sodium oleate. The outer surfaces of the nanometer-sized BaWO{sub 4}:Eu phosphors were capped by the long alkyl chain of oleate; therefore, the hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors preferentially dissolved in the hexane layer. The micrometer-sized BaWO{sub 4}:Eu phosphors were obtained in the water layer. The BaWO{sub 4}:Eu phosphors prepared in hexane and water yielded sharp strong absorption and emission peaks at 464 and 615 nm, respectively, due to the {sup 7}F{sub 0} → {sup 5}D{sub 2} and the {sup 5}D{sub 0} →{sup 7} F{sub 2} transitions of the Eu{sup 3+} ions. The BaWO{sub 4}:Eu phosphors are good candidate red-emitting phosphors for use in InGaN blue-emitting diodes, which have an emission wavelength of 465 nm.},
doi = {10.1016/J.MATERRESBULL.2016.02.020},
journal = {Materials Research Bulletin},
number = ,
volume = 78,
place = {United States},
year = 2016,
month = 6
}
  • The extent and kinetics of adsorption of a peat-derived humic substance (HS) onto a hydrophobic surface (mercury electrode) and a polar mineral surface ([gamma]-Al[sub 2]O[sub 3] colloids) was studied. Adsorption on the Hg-electrode was assessed by directly measuring the change of the double layer capacitance caused by the adsorption of HS on the electrode surface through phase-selective a.c. polarography; the extent of adsorption of HS on the [gamma]-Al[sub 2]O[sub 3]-surface was monitored by determining the residual HS-concentration in solution. On both surfaces, HS is adsorbed strongly over a wide pH-range; hydrophobic interaction (i.e., expulsion from solution) prevails at the mercurymore » surface while coordinative adsorption (ligand exchange), enhanced by hydrophobic effects, is the predominant mechanism at the oxide surface. Adsorption kinetics are characterized by an initial fast process, where even in dilute solutions (<1 mg HS L[sup [minus]1]), a high surface coverage is attained initially. True adsorption equilibrium, however, cannot be reached within hours. The slow approach to equilibrium is though to be caused mainly by the polydispersity of HS resulting in fractionation processes, where presumably fast-adsorbing low-molecular weight compounds are successively displaced from the surface by slow-adsorbing compounds of higher molecular weight. Slow molecular rearrangements of HS-molecules at the interface cannot be ruled out, however. These results suggest that adsorption of humic substances on mineral as well as hydrophobic aquatic surfaces may lead to a progressive and selective immobilization of certain fractions of humic substances. This may have significant effects on the qualitative composition and reactivity of dissolved vs. particulate organic carbon and on the residence time of different fractions of humic substances in natural systems.« less
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  • No abstract prepared.