scholarly journals In Situ Synthesis of β-Na1.5Y1.5F6: Er3+ Crystals in Oxyfluoride Silicate Glass for Temperature Sensors and Their Spectral Conversion and Optical Thermometry Analysis

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6901
Author(s):  
Rajesh Dagupati ◽  
Robert Klement ◽  
Ramaraghavulu Rajavaram ◽  
José J. Velázquez ◽  
Dušan Galusek
Keyword(s):  
Energy Levels ◽  
Glass Ceramics ◽  
Relative Sensitivity ◽  
Spectroscopic Techniques ◽  
Temperature Dependent ◽  
Optical Thermometry ◽  
Bright Green ◽  
Quenching Method ◽  
Doped Glass

Transparent oxyfluoride glass-ceramics (GCs) with embedded β-Na1.5Y1.5F6 crystals doped with Er3+ ions were fabricated by a melt-quenching method with subsequent heat-treatment. The structural characterizations and spectroscopic techniques were performed to verify the precipitation of β-Na1.5Y1.5F6 crystals and partition of the Er3+ dopant into the crystals. Bright green up-conversion (UC) emission was achieved in Er3+-doped glass-ceramic (Er-GC). Furthermore, the temperature-dependent visible UC behavior based on thermally coupled energy levels (TCLs) and non-thermally coupled energy levels (NTCLs) was also examined in the temperature range 298 k to 823 K with maximum relative sensitivity (Sr) of 1.1% K−1 at 298 K for TCLs in Er-G and Er-GC samples.

Temperature-dependent broadband near-infrared luminescence in silicate glass ceramics containing Li2MgSiO4: Cr4+ nanocrystals

2010 ◽  
Vol 25 (9) ◽  
pp. 1833-1837 ◽  
Author(s):  
Yixi Zhuang ◽  
Jiajia Zhou ◽  
Junhua Xie ◽  
Yu Teng ◽  
Jianrong Qiu
Keyword(s):  
Fluorescence Lifetime ◽  
Near Infrared ◽  
Glass Ceramics ◽  
Infrared Emission ◽  
Temperature Dependent ◽  
Energy Level Scheme ◽  
Mixed Effect ◽  
Infrared Luminescence ◽  
Doped Glass ◽  
Near Infrared Emission

Transparent glass ceramics containing Li2MgSiO4: Cr4+ nanocrystallites were prepared. Intense broadband near-infrared emission with full width at half-maximum larger than 200 nm and long fluorescence lifetime (τ > 100 μs) were observed. The temperature-dependent optical characteristics of the glass ceramics containing Li2MgSiO4: Cr4+ crystallites were compared to those of Li2MgSiO4: Cr4+ single crystals. The reason for extra-long near-infrared fluorescence lifetime was illuminated by the mixed effect between 3T2 and 1E levels. The crystal-filed-induced particular energy-level scheme makes the fluorescence lifetime of the glass ceramics containing Li2MgSiO4: Cr4+ crystallites one order longer than those of other Cr4+-doped glass ceramics.

Eu3+-Doped glass ceramics containing NaTbF4 nanocrystals: controllable glass crystallization, Tb3+-bridged energy transfer and tunable luminescence

2017 ◽  
Vol 5 (39) ◽  
pp. 10201-10210 ◽  
Author(s):  
Xinyue Li ◽  
Xiao Chen ◽  
Shuo Yuan ◽  
Shen Liu ◽  
Chao Wang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Wavelength Range ◽  
Energy Levels ◽  
Glass Ceramics ◽  
Glass Crystallization ◽  
Visible Wavelength ◽  
Radiative Transitions ◽  
Visible Wavelength Range ◽  
Doped Glass

The ET chains of (a) Tb3+ → (Tb3+)n → Q and (b) Tb3+ → (Tb3+)n → Eu3+. (c) The energy levels of Tb3+ and Eu3+ ions, the related radiative transitions and the possible ET routes. (d) Main luminescent transitions of Tb3+ and Eu3+ in the visible wavelength range.

scholarly journals LiYF4-nanocrystal-embedded glass ceramics for upconversion: glass crystallization, optical thermometry and spectral conversion

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2066-2073
Author(s):  
Xinyue Li ◽  
Liting Qiu ◽  
Youli Chen ◽  
Yiwen Zhu ◽  
Hua Yu ◽  
...  
Keyword(s):  
Glass Ceramics ◽  
Glass Crystallization ◽  
Melt Quenching ◽  
Optical Thermometry ◽  
Quenching Method ◽  
Spectral Conversion

LiYF4 NCs embedded GCs were fabricated via melt-quenching method and subsequent glass crystallization. It is evidenced that it is favorable of UC, which is promising in optical thermometry and spectral conversion.

Synthesis of sandwich type acyclic tetra-nuclear silver(I)-N-heterocyclic carbene complexes for wound healing applications

2020 ◽  
Vol 75 (9-10) ◽  
pp. 369-376
Author(s):  
Ayesha Riaz ◽  
Muhammad Adnan Iqbal ◽  
Haq Nawaz Bhatti ◽  
Muhammad Shahid
Keyword(s):  
Alkyl Halides ◽  
Wound Contraction ◽  
Spectroscopic Techniques ◽  
Open Chain ◽  
Standard Drug ◽  
Sandwich Type ◽  
Benzimidazolium Salts ◽  
Multistep Reaction

AbstractTwo meta-xylyl linked tetrakis-benzimidazolium salts (L1-L2) as multidentate ligands and two respective silver complexes (C1 and C2) were synthesized. A multistep reaction was done at room temperature, starting with simple benzimidazole and alkyl halides, going through precursors and salt formation by reflux and finally in situ deprotonation of tetrabenzimidazolium salts with Ag2O to yield respective tetra-nuclear Ag(I)-N-heterocyclic Carbene (NHC) complexes. Propyl and butyl groups were bonded at the terminal positions of tetra-azolium open chain salts. Characterization of compounds was done by analytical and spectroscopic techniques. On the basis of spectroscopic data, a chemical structure with open chains having four Ag(I) ions sandwiched between NHC layers was established. Potential of synthesized complexes (C1 & C2) for wound contraction was evaluated and compared with standard wound contraction gel. Percentage wound contraction of both complexes was found very close to that of standard drug used in parallel.

Crystal structure and temperature-dependent properties of Na2H4Ga2GeO8 – a novel gallogermanate

2020 ◽  
Vol 75 (9-10) ◽  
pp. 805-813
Author(s):  
Irma Peschke ◽  
Lars Robben ◽  
Christof Köhler ◽  
Thomas Frauenheim ◽  
Josef-Christian Buhl ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Decomposition Temperature ◽  
Spectroscopic Techniques ◽  
Charge Balance ◽  
Temperature Dependent ◽  
Raman Spectroscopic ◽  
Debye Temperatures ◽  
Diffraction Lattice ◽  
Temperature Dependent Properties ◽  
Balance Structure

AbstractSynthesis, crystal structure and temperature-dependent behavior of Na2H4Ga2GeO8 are reported. This novel gallogermanate crystallizes in space group I41/acd with room-temperature powder diffraction lattice parameters of a = 1298.05(1) pm and c = 870.66(1) pm. The structure consists of MO4 (M = Ga, Ge) tetrahedra in four-ring chains, which are connected by two different (left- and right-handed) helical chains of NaO6 octahedra. Protons coordinating the oxygen atoms of the GaO4 tetrahedra not linked to germanium atoms ensure the charge balance. Structure solution and refinement are based on single crystal X-ray diffraction measurements. Proton positions are estimated using a combined approach of DFT calculations and NMR, FTIR and Raman spectroscopic techniques. The thermal expansion was examined in the range between T = 20(2) K and the compound’s decomposition temperature at 568(5) K, in which no phase transition could be observed, and Debye temperatures of 266(11) and 1566(65) K were determined for the volume expansion.

In Situ Analysis of Surface Contaminant Desorption during Low-Temperature Silicon Substrate Cleaning using Reflection Electron Energy Loss Spectrometry

1992 ◽  
Vol 259 ◽  
Author(s):  
Selmer S. Wong ◽  
Shouleh Nikzad ◽  
Channing C. Ahn ◽  
Aimee L. Smith ◽  
Harry A. Atwater
Keyword(s):  
Low Temperature ◽  
Energy Loss ◽  
Electron Energy ◽  
Core Loss ◽  
Temperature Dependent ◽  
Electron Energy Loss Spectrometry ◽  
Analysis Technique ◽  
Chemical Analysis Technique ◽  
Electron Energy Loss

ABSTRACTWe have employed reflection electron energy loss spectrometry (REELS), a surface chemical analysis technique, in order to analyze contaminant coverages at the submonolayer level during low-temperature in situ cleaning of hydrogen-terminated Si(100). The chemical composition of the surface was analyzed by measurements of the C K, O K and Si L2,3 core loss intensities at various stages of the cleaning. These results were quantified using SiC(100) and SiO2 as reference standards for C and O coverage. Room temperature REELS core loss intensity analysis after sample insertion reveals carbon at fractional monolayer coverage. We have established the REELS detection limit for carbon coverage to be 5±2% of a monolayer. A study of temperature-dependent hydrocarbon desorption from hydrogen-terminated Si(100) reveals the absence of carbon on the surface at temperatures greater than 200°C. This indicates the feasibility of epitaxial growth following an in situ low-temperature cleaning and also indicates the power of REELS as an in situ technique for assessment of surface cleanliness.

Molecular modulation of calcium oxalate crystallization

2006 ◽  
Vol 291 (6) ◽  
pp. F1123-F1132 ◽  
Author(s):  
James J. De Yoreo ◽  
S. Roger Qiu ◽  
John R. Hoyer
Keyword(s):  
Molecular Modeling ◽  
Calcium Oxalate ◽  
Stone Formation ◽  
Energy Levels ◽  
Critical Role ◽  
Specific Interactions ◽  
Crystal Surfaces ◽  
Site Specific

Calcium oxalate monohydrate (COM) is the primary constituent of the majority of renal stones. Osteopontin (OPN), an aspartic acid-rich urinary protein, and citrate, a much smaller molecule, are potent inhibitors of COM crystallization at levels present in normal urine. Current concepts of the role of site-specific interactions in crystallization derived from studies of biomineralization are reviewed to provide a context for understanding modulation of COM growth at a molecular level. Results from in situ atomic force microscopy (AFM) analyses of the effects of citrate and OPN on growth verified the critical role of site-specific interactions between these growth modulators and individual steps on COM crystal surfaces. Molecular modeling investigations of interactions of citrate with steps and faces on COM crystal surfaces provided links between the stereochemistry of interaction and the binding energy levels that underlie mechanisms of growth modification and changes in overall crystal morphology. The combination of in situ AFM and molecular modeling provides new knowledge that will aid rationale design of therapeutic agents for inhibition of stone formation.

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