A5100334102- Luminescence Properties of Advanced Materials
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Advanced Photocatalysis Techniques
- Perovskite Materials and Applications
- Gas Sensing Nanomaterials and Sensors
- Lanthanide and Transition Metal Complexes
- Crystal Structures and Properties
- Polyoxometalates: Synthesis and Applications
- Inorganic Chemistry and Materials
- Ammonia Synthesis and Nitrogen Reduction
- Luminescence and Fluorescent Materials
- Ga2O3 and related materials
- Copper-based nanomaterials and applications
- Crystallography and molecular interactions
- Radical Photochemical Reactions
- Catalytic Processes in Materials Science
- Microwave Dielectric Ceramics Synthesis
- Molecular Sensors and Ion Detection
- Nanocluster Synthesis and Applications
- Nuclear materials and radiation effects
- Solid-state spectroscopy and crystallography
- Glass properties and applications
Ajou University
2016-2025
Government of the Republic of Korea
2015-2018
Suwon Research Institute
2018
Silla University
2014-2017
A blue-emitting SiO<sub>2</sub>:Eu<sup>2+</sup> compound has been successfully synthesized and characterized.
Novel LiCe9(SiO4)6O2 and LiTb9(SiO4)6O2 compounds have been successfully synthesized, the site selectivity occupancy of activator ions estimated including LiEu9(SiO4)6O2 compound. The rare earth (RE) fully occupied compounds, as well RE partially congeners are required for assessment (activator) in apatite-type compounds. splitting energies 6H 4F Wycoff positions LiRE9(SiO4)6O2 (RE = Ce, Eu, Tb) calculated based on crystal field theory: ΔECe(6H) 3849.3 cm–1, ΔECe(4F) 4228.1 ΔEEu(6H) 3870.0...
Eu2+-activated M5(PO4)3X (M = Ca, Sr, Ba; X F, Cl, Br) compounds providing different alkaline-earth metal and halide ions were successfully synthesized characterized. The emission peak maxima of the M5(PO4)3Cl:Eu2+ Ba) blue-shifted from Ca to Ba (454 nm for 444 434 Ba), those Sr5(PO4)3X:Eu2+ (X red-shifted along series halides, F → Cl Br (437 448 Br). site selectivity occupancy activator (Eu2+) in M5(PO4)3X:Eu2+ crystal lattices estimated based on theoretical calculation 5d 4f transition...
Novel blue-emitting LaOBr:Eu2+ and LaOI:Eu2+ phosphors have been successfully synthesized compared to LaOCl:Eu2+. The emission spectra of LaOX:Eu2+ (X = Cl, Br, I) show that the peak maxima change somewhat red-shift region; 425 nm for LaOCl:Eu2+, 427 LaOBr:Eu2+, 431 LaOI:Eu2+, which is quite opposite one based on spectrochemical series (I– < Br– Cl–). From diffuse reflectance spectra, band gap energies LaOCl, LaOBr, LaOI host lattice are estimated as 5.53 eV (44 594 cm–1), 5.35 (43 142 4.82...
A novel blue-emitting LaOCl:Eu2+ phosphor has been successfully synthesized using the solid-state reaction. In addition, Ce3+ and Tb3+ activated LaOCl phosphors have prepared compared with phosphor. FE-SEM images clearly indicate that a lamellar structure. XRD results PL measurements for preferred orientation along [001] direction, which in blue-emission associated spectral characteristics of Eu2+. contrast, red-emission due to formation Eu3+ appears non-oriented one. These reveal Eu2+ ions...
In the search for well-defined phosphor materials white NUV-LEDs, highly enhanced luminous efficacy by N(3-) doping as well color tunability via Ca substitution has been successfully obtained in Ba2-xCaxSiO4-δN2/3δ:Eu(2+) (x = 0.0, 0.5, 0.8, 1.0) phosphors. With increasing Ca-substitution rate, crystal structures of are changed from primitive orthorhombic structure to hexagonal one, so that CIE coordinates move bluish-green (at 0.0), blue 0.5), and finally near region 0.8 these materials....
Blue-emitting Ca2–xMgxSiO4:Ce (0.0 ≤ x 1.0) phosphors were successfully synthesized and characterized. Rietveld refinement revealed that four main phases exist within the solid-solution range of CaO-MgO-SiO2, namely, β-Ca2SiO4 (Mg (x) = 0.0), Ca14Mg2(SiO4)8 0.25), Ca3Mg(SiO4)2 0.5), CaMgSiO4 1.0). The variation IR modes was more prominent with increasing Mg2+ content in Ca2–xMgxSiO4 materials. sharing O atoms SiO4-tetrahedra by MgO6-octahedra induced weakening Si–O bonds, which resulted red...
Abstract Organic–inorganic copper(I) halide complexes have attracted attention due to their optoelectronic properties and non‐toxic nature. In this study, we systematically synthesized melamine as single crystals, (CuBr(melamine) CuI(melamine)) polycrystalline powders, CuBr x I 1‐ (melamine) (0 ≤ 1). The crystal structures of CuBr(melamine) CuI(melamine) are isotypic with a triclinic space group P , where is connected three adjacent halides along the ‐axis ligand c ‐axis, forming an infinite...
Self-emitting blue and red EuOX (X = F, Cl, Br, I) were successfully synthesized characterized. Far-infrared Raman measurements revealed that the vibration modes prominently reflected Eu-O Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) red-emitting compounds showed Eu exclusively existed as Eu3+, while in blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For Br), maximum wavelengths charge-transfer (CT) bands red-shifted: F → Cl Br (282, 320, 330 nm...
The PL intensity of Li-doped Ba<sub>2</sub>SiO<sub>4</sub>:Eu<sup>2+</sup> (Li = 200% excess) is found to be 470% higher than that (no-Li). excess Li<sub>2</sub>CO<sub>3</sub> autonomously removes the impurities contained in low-purity precursors, particular SiO<sub>2</sub>.
The N3–-substituted Li2MSiO4:Eu2+ (M = Ca, Sr, and Ba) phosphors were systematically prepared analyzed. Secondary-ion mass spectroscopy measurements revealed that the average N3– contents are 0.003 for 0.009 0.032 Ba. Furthermore, incorporation in host lattices was corroborated by infrared X-ray photoelectron spectroscopies. From photoluminescence spectra of before after doping, it verified enhanced emission intensity is most likely due to doping. In phosphors, maximum wavelengths band...
Ba2SiO4−δN2/3δ:Eu2+ (BSON:Eu2+) materials with different N3− contents were successfully prepared and characterized. Rietveld refinements showed that ions partially substituted for the O2− in SiO4-tetrahedra because bond lengths of Si‒(O,N) (average value = 1.689 Å) slightly elongated compared those Si‒O 1.659 Å), which resulted minute compression Ba(2)‒O from 2.832 to 2.810 Å. The average BSON:Eu2+ phosphors determined 100 nm 2000 depth grain using a secondary ion mass spectrometry (SIMS):...
Eu(Phen)<sub>2</sub><sup>3+</sup> complexes are successfully intercalated into smectite minerals. The red-emitting : hybrids is dramatically converted the blue-emission by hydrazine-reduction.
Abstract The title compounds are prepared from stoichiometric mixtures of MCO 3 (M: Sr, Ca, Ba), Eu 2 O , NH 4 X (X: F, Cl, Br), and (NH )H PO (4% H /Ar, 1100 °C, h) characterized by powder XRD, XPS, photoluminescence, IR, UV/VIS spectroscopy.