Search results for "luminescence."
showing 10 items of 1568 documents
ChemInform Abstract: Facile Synthesis and Characterization of Monocrystalline Cubic ZrO2Nanoparticles.
2008
Abstract Crystalline ZrO2 nanoparticles were prepared from zirconium isopropoxide by slow hydrolysis and subsequent hydrothermal treatment of solutions containing various amounts of sodium hydroxide at 180 °C. Whereas moderately basic solutions lead to the formation of nanoparticles of monoclinic ZrO2 with plate-like morphology, and nanoparticles of the cubic ZrO2 high-temperature polymorph with diameters of approx. 5 nm were obtained from strongly basic solutions. The morphology, structure and properties of as-synthesized nanoparticles were characterized using HRTEM, XRD, Raman spectroscopy, UV–vis, PL spectroscopy and BET measurements. The formation of both, the monoclinic and the cubic p…
Chemical Bath Deposition as a Simple Way to Grow Isolated and Coalesced ZnO Nanorods for Light-Emitting Diodes Fabrication
2018
A way to grow and characterize isolated and coalesced ZnO nanorods on $p$ -GaN/sapphire structure is presented. Chemical bath deposition can be used to grow ZnO nanorods of device-quality, simply controlling the duration time of the growth process and the concentration of the nutrient solution in the bath. Increasing the duration of the process, as well as the concentration of the solution, leads to compact and sound layers instead of separated nanorods. However, too high concentrations stop the growth process. Light-emitting diodes fabricated on these ZnO-p-GaN heterostructure have a peak of electroluminescence at 400 nm and exhibit interesting electrical and optical properties. Optical po…
Amine functionalized ZrO2 nanoparticles as biocompatible and luminescent probes for ligand specific cellular imaging
2015
Surface functionalized ZrO2 nanoparticles show strong photoluminescence and are a versatile tool for cellular targeting due to their chemical functionality. They are highly photostable, biocompatible and amenable to coupling with bioligands (e.g. secondary goat anti-rabbit antibody (GAR) and tri-phenyl phosphine (TPP)) via carbodiimide chemistry. Antibody (GAR) functionalized ZrO2 nanoparticles were used to image the nuclear protein Sirt6, whereas triphenyl phosphonium ion (TPP) functionalized ZrO2 nanoparticles specifically targeted the mitochondria. The versatility and easiness of the ZrO2 surface modification opens up new possibilities for designing non-toxic water dispersible and photos…
Photophysical Investigation of Iron(II) Complexes Bearing Bidentate Annulated Isomeric Pyridine-NHC Ligands
2020
The possibility of achieving luminescent and photophysically active metal-organic compounds relies on the stabilization of charge transfer states and kinetically and thermodynamically blocking non-...
Polyamines and applications. A look at the first workshop in linear and cyclic polyamines chemistry
2008
Given their versatile coordination properties, cyclic and linear polyamines are the subject of numerous worksin many research groups. This great interest is mainly related to their use in diverse fields such as removalof metals from liquids, purification of gases, application in catalysis, in sensors, as well as in various probesfor medical applications. This paper summarizes recent results obtained by the French research groupswhich attended the first ìworkshop in linear and cyclic polyamines chemistryî.
Near-field observation of subwavelength confinement of photoluminescence by a photonic crystal microcavity
2006
We present a direct, room-temperature near-field optical study of light confinement by a subwavelength defect microcavity in a photonic crystal slab containing quantum-well sources. The observations are compared with three-dimensional finite-difference time-domain calculations, and excellent agreement is found. Moreover, we use a subwavelength cavity to study the influence of a near-field probe on the imaging of localized optical modes. © 2006 Optical Society of America.
Single-mode room-temperature emission with a silicon rod lattice
2006
The authors experimentally evidence an increase of light emission efficiency at room temperature in a silicon-on-insulator photonic crystal. The photonic crystal is made of a triangular lattice of silicon rods and operates as a single-mode light extractor. It exhibits a luminescence intensity two orders of magnitude higher than silicon-on-insulator substrate. In light of photoluminescence experiments, emission diagram measurements, and finite difference time domain calculations, they identify the different optical properties of the photonic crystal and they demonstrate the existence of at least a fivefold emission efficiency enhancement per surface unit.
Nanobox array for silicon-on-insulator luminescence enhancement at room temperature
2006
We report the light extraction enhancement obtained at room temperature from a square lattice of crystalline silicon nanoboxes etched in a silicon-on-insulator substrate. Luminescence spectra recorded under optical pumping show a 125 times emission enhancement as compared with the reference unpatterned silicon-on-insulator emission. In light of band diagram calculations, it is demonstrated that the emission enhancement partially results from the coupling between electron-hole recombination inside the silicon boxes and low group velocity optical modes of the array. Moreover, it is observed that these modes present different decoupling lengths and that a complete extraction of luminescence ca…
X-ray irradiation influence on prototype Er3+-optical fibers: confocal luminescence study
2010
International audience; The integration of rare-earth doped optical fibers as part of fiber-based systems in space implies the development of waveguides tolerant to the radiation levels associated with the space missions. We report the spatial distribution, the photoluminescence (PL) properties of color centers and the related changes induced by X-rays radiation at different doses (50, 500 and 1000 krad) for two different prototypes of Er-doped optical fibers. Each sample (in the version pristine, X-irradiated and H2 loaded prior to radiation exposure) was characterized by confocal microscopy luminescence (CML) measurements in Visible range with Visible (488 nm) or UV (325 nm) laser light e…
γ-ray induced GeODC(II) centers in germanium doped α-quartz crystal
2011
International audience; Main luminescence of α-quartz crystal doped with germanium results from the luminescence of a self-trapped exciton (STE) near germanium. In as grown Ge-doped α-quartz crystal, the luminescence associated with the twofold coordinated Ge center (GeODC) in amorphous silica glass doped with germanium, was never observed. In this work, we performed experiments to investigate if a GeODC like luminescence could appear after a γ-irradiation of a Ge-doped α-quartz crystal. The answer is positive: under excitation with pulsed light of an ArF laser (193 nm): a new luminescence with two bands -- a blue one associated to a time constant of about 100 μs appears and another one wit…