A5014799989- Glass properties and applications
- Advanced NMR Techniques and Applications
- High-pressure geophysics and materials
- Advanced Condensed Matter Physics
- Solid-state spectroscopy and crystallography
- Clay minerals and soil interactions
- Geological and Geochemical Analysis
- Crystal Structures and Properties
- NMR spectroscopy and applications
- Material Dynamics and Properties
- Microstructure and Mechanical Properties of Steels
- Perovskite Materials and Applications
- Mineralogy and Gemology Studies
- X-ray Diffraction in Crystallography
- Hydrocarbon exploration and reservoir analysis
- Pain Management and Treatment
- Anesthesia and Sedative Agents
- Anesthesia and Pain Management
- Pain Mechanisms and Treatments
- Fatigue and fracture mechanics
- Luminescence Properties of Advanced Materials
- Conducting polymers and applications
- earthquake and tectonic studies
- Nuclear materials and radiation effects
- Paleontology and Evolutionary Biology
Seoul National University
2016-2025
Inha University
1998-2020
Dong-A University
1993-2010
Electronics and Telecommunications Research Institute
2010
Materials Science & Engineering
2010
Université d'Orléans
2009
Conditions Extrêmes et Matériaux Haute Température et Irradiation
2009
Centre National de la Recherche Scientifique
2009
Carnegie Institution for Science
2003-2008
Geophysical Laboratory
2003-2008
Abstract Perovskite light-emitting diodes (PeLEDs) based on three-dimensional (3D) polycrystalline perovskites suffer from ion migration, which causes overshoot of luminance over time during operation and reduces its operational lifetime. Here, we demonstrate 3D/2D hybrid PeLEDs with extremely reduced 21 times longer lifetime than 3D PeLEDs. The ratio PeLED is only 7.4% greatly lower that (150.4%). perovskite obtained by adding a small amount neutral benzylamine to methylammonium lead...
Synthetic epidotes were produced using a Tuttle type hydrothermal vessel in the temperature range from 500 to 700 ℃ and at 4.5 5.0 kbars pressure. Single-crystal X-ray diffraction structure refinements yielded intracrystalline cation distributions for two crystals grown 600 (0.68 0.73 Fe apfu) five (0.88 1.08 apfu). The resulting occupancies compared with those calculated according thermodynamic model: samples formed display distribution between M3 Ml sites that match calculation;...
Whereas prototypical Al(2)O(3) is not a glass former, amorphous can be formed as thin films through vapor deposition and serve structural model for the glass. The first two-dimensional solid-state NMR experiments film reveal that four- five-coordinated species are predominant (95%), while six-coordinated minor. Such distribution remarkably similar to what has been predicted theoretically melts. Upon annealing 800 degrees C becomes negligible, indicating onset of crystallization Al(2)O(3).
We investigate short-range order and local atomic configuration in charge-balanced aluminosilicate glasses as functions of composition, using 17O 27Al MAS triple-quantum magic angle spinning (3QMAS) NMR spectroscopy. Enhanced resolution 3QMAS spectra, compared to NMR, allows the quantification spectra extent disorder a semiempirical function relating efficiency quadrupolar coupling constant (Cq). The variations with Si/Al ratio (R) peak positions widths isotropic dimension both Na-...
The fraction of O atoms as non-bridging (NBO) can be well approximated based on composition alone in many silicate glasses, but the NBO preference for specific network forming cations is much less known. Using oxygen-17 (17O) NMR low-silica calcium aluminosilicate (CAS) this study shows that Al-NBO (155 ppm) readily distinguished from Si-NBO (110-120 ppm), and there a strong latter. This also presents consistent equilibrium constant formulation indicates thermodynamic modeling most CAS melts...
Soda-lime silicate glass is the fundamental base for many technologically important oxide glasses, and it has been used as window since Roman Empire. Mixed-cation silicates also are useful models of structure dynamics basaltic magmas mantle melts. The diffusivity Na+ in melts its variation with composition play key roles melting behavior. This property depends strongly on framework structures glasses presence other types nearby cations that often impede Na motion; this known a mixed cation...
Silicate melts at the top of transition zone and core-mantle boundary have significant influences on dynamics properties Earth's interior. MgSiO3-rich silicate were among primary components magma ocean thus played essential roles in chemical differentiation early Earth. Diverse macroscopic interior, such as density, viscosity, crystal-melt partitioning, depend their electronic short-range local structures high pressures temperatures. Despite many geophysical geodynamic problems, little is...
Revealing the extent of disorder in amorphous oxides is one remaining puzzles physical chemistry, glass sciences, and geochemistry. Here, we report 27Al NMR results for Al2O3 thin films obtained from two different deposition methods (i.e., vapor-deposition atomic layer-deposition), revealing distinct states defined by a fraction five-coordinated Al ([5]Al). The fractions [4]Al [5]Al are dominant (∼92−95%) both films. While overall similarity between these suggests narrow stability available...
The quantification of the intrinsic disorder in archetypal noncrystalline magnesium aluminosilicates remains unsolved. This lack knowledge is because increased structural perturbation caused by Mg2+, a high field strength cation, resulting substantial broadening both spectral and scattering responses. Most progress regarding amorphous aluminosilicate has thus been made with relatively low cations (e.g., Na+ Ca2+). Here, we quantified nature Mg-aluminosilicate glasses enstatite...
Application of two-dimensional (2D) organic–inorganic hybrid halide perovskites in optoelectronic devices requires a detailed understanding the local structural features including Pb–I bonding 2D layers and interaction between organic spacer molecules perovskite layer. In this study, we show that 1H 207Pb solid-state nuclear magnetic resonance (NMR) spectroscopy can serve as noninvasive complementary technique to probe Ruddlesden–Popper phase BA2MAn–1PbnI3n+1 (n = 1–4) with butylammonium...
We report paragenesis and chemistry of a new occurrence the rare trioctahedral Al-rich sodium mica preiswerkite. The preiswerkite occurs in tourmaline-biotite-scapolite rock contact zone gabbroic boudin surrounded by Proterozoic metasediments near Blengsvatn, Bamble sector, southern Norway. as subhedral crystals or is intergrown with biotite polygonal fabric together Cl-rich scapolite + tourmaline ± ilmenite ±plagioclase ±corundum. Accessory minerals are hematite, högbomite, spinel,...
Despite their strong implications for magmatic processes in the earth's interior and pressure-induced structural changes other amorphous, covalent oxide materials, little is known, beyond coordination numbers of framework cations, about structures silicate melts glasses at high pressure. Here, we use multinuclear (27Al 17O) solid-state NMR quantum chemical calculations to study quenched from pressures up 10 GPa a multianvil apparatus. The atomic configurations include formation highly...
We report spectroscopic evidence for the pressure-induced structural changes in ${\mathrm{B}}_{2}{\mathrm{O}}_{3}$ glass quenched from melts at pressures up to 6 GPa using solid-state NMR. While all borons are tri-coordinated 1 atm, fraction of tetra-coordinated boron increases with pressure, being about 5% and 27% 2 GPa, respectively. The boroxol ring species pressure apparently decreases further compression GPa. Two densification mechanisms proposed explain variation pressure.
Pressure-induced changes in properties of multicomponent silicate melts magma oceans controlled chemical differentiation the earth and composition partial that might have formed hidden reservoirs. Although melt show complex pressure dependences, structures at high atomistic origins these are largely unknown because their pressure–composition dependence, intrinsic to magmatic melts. Chemical constraints such as nonbridging oxygen (NBO) content 1 atm, rather than structural parameters for...
Lithium-rich layered oxides (LLOs) have attracted tremendous attention as promising next generation cathode materials thanks to their superb capacity through additional anionic oxygen redox and lower cost by less use of expensive transition metals.