Search results for "Dopant"
showing 10 items of 162 documents
Polymer-Functionalised Nanograins of Mg-Doped Amorphous Calcium Carbonate via a Flow-Chemistry Approach
2019
Calcareous biominerals typically feature a hybrid nanogranular structure consisting of calcium carbonate nanograins coated with organic matrices. This nanogranular organisation has a beneficial effect on the functionality of these bioceramics. In this feasibility study, we successfully employed a flow-chemistry approach to precipitate Mg-doped amorphous calcium carbonate particles functionalized by negatively charged polyelectrolytes&mdash
Certain doping concentrations caused half-metallic graphene
2017
This work is supported by National Natural Science Foundation of China (Grant No. 21173096).
Magnetic phase diagrams in heavy-fermion compounds
1990
Magnetic phase diagrams have been explored in heavy-fermion (HF) compounds by controlled changes of the stoichiometry (UCu4+xAl8−x), dopant concentration (Ce(Cu1−xNix)2Ge2) and magnetic field (CeCu2Si2). The results demonstr competition (i) between Kondo and RKKY interactions in the former two compounds and (ii) between HF superconductivity and some cooperative state, presumably HF band magnetism, in the latter.
NanoMORALs: Metal Nanoparticles Doped with Organic Molecules
2009
A new class of nanosized metal–organic alloys (MORALs) has been synthesized for the first time. Silver nanoparticles doped with Cu(II) and Fe(III) phthalocyanines were thus synthesized in the presence of sodium dodecyl sulfate (SDS). The resulting materials were characterized by means of XRD, SEM, TEM coupled to energy dispersive X-ray analysis, and thermogravimetric analysis. No leaching of the photoactive dopant species was observed in water or in common organic solvents.
An inconvenient influence of iridium(III) isomer on OLED efficiency.
2010
The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact pe…
First Principles Calculations of Atomic and Electronic Structure of TiAl3+- and TiAl2+-Doped YAlO3
2021
In this paper, the density functional theory accompanied with linear combination of atomic orbitals (LCAO) method is applied to study the atomic and electronic structure of the Ti3+ and Ti2+ ions substituted for the host Al atom in orthorhombic Pbnm bulk YAlO3 crystals. The disordered crystalline structure of YAlO3 was modelled in a large supercell containing 160 atoms, allowing simulation of a substitutional dopant with a concentration of about 3%. In the case of the Ti2+-doped YAlO3, compensated F-center (oxygen vacancy with two trapped electrons) is inserted close to the Ti to make the unit cell neutral. Changes of the interatomic distances and angles between the chemical bonds in the de…
UV light induced processes in pure and doped AlN ceramics
2021
The present research has been sponsored by the Latvian Council of Science , Grant No. lzp-2018/1-0361 “Research of luminescence mechanisms and dosimeter properties in prospective nitrides and oxides using TL and OSL methods “; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 73950 , project CAMART 2
The effect of Mo and Ge reactive elements on high-temperature oxidation of higher manganese silicide
2021
Abstract Higher manganese silicide (HMS) alloys (Mnx-αMoαSiy-βGeβ (x = 0.99–1.011, α = 0.005–0.02, y = 1.75, β = 0.005–0.01)) were studied to elucidate the effect of Mo and Ge pertaining to oxidation. Oxidation experiments were conducted using thermogravimetry and characterized using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Isoconversion experiments below 450 °C, shows that doping (up to 2 at%) raises the oxidation potential of HMS. Isothermally, the oxidation rate reduces buy one order of magnitude by doping on Mn and/or Si sites from 0.5 to 2 at%, revealing that the dopants-based oxides do not lessen the robustness of SiO2 oxide.
Local Environment of Yttrium in Y-Doped Barium Cerate Compounds
2006
The local structure of yttrium in Y-doped BaCeO3 compounds was studied using X-ray absorption spectroscopy (XAS) at the Y K-edge. Data analysis shows that the local environment of Y3+ changes, resulting in a distorted octahedron. The structural distortion found does not depend on the dopant amount at the investigated compositions, but on the level of hydration, as clearly demonstrated by the distortion increase in the BaCe0.9Y0.1O3-ä sample after the treatment in O2/H2O. In situ measurements performed in O2/H2O flux, which show that the distortion is retained at 753 K, are also reported. The observed significative structural changes seem to point out a preferential insertion of the hydroxyl…
Luminescence properties of zirconia nanocrystals prepared by solar physical vapor deposition
2014
Abstract Zirconia nanocrystals have attracted considerable interest as biolabels, which can be used as probes for medical imaging and biosensor applications. However, zirconia particle agglomeration forms a major limitation to its use for biolabeling. In this backdrop, for the first time, well-separated zirconia nanocrystals were obtained in a Heliotron reactor (PROMES CNRS, France) via the solar physical vapor deposition (SPVD) method. As the raw material target for solar evaporation, zirconia nanopowders obtained via the sol–gel process were used. The luminescence and upconversion luminescence properties of the Sol Gel nanopowders were compared with those of the SPVD nanocrystals. Erbium …