Search results for "doping"
showing 10 items of 801 documents
Supramolecular control of liquid crystals by doping with halogen-bonding dyes
2017
Introducing photochromic or polymeric dopants into nematic liquid crystals is a well-established method to create stimuli-responsive photonic materials with the ability to "control light with light". Herein, we demonstrate a new material design concept by showing that specific supramolecular interactions between the host liquid crystal and the guest dopants enhance the optical performance of the doped liquid crystals. By varying the type and strength of the dopant-host interaction, the phase-transition temperature, the order parameter of the guest molecules, and the diffraction signal in response to interference irradiation, can be accurately engineered. Our concept points out the potential…
Influence of Nitrogen Doping on Device Operation for TiO 2 -Based Solid-State Dye-Sensitized Solar Cells: Photo-Physics from Materials to Devices
2016
International audience; Solid-state dye-sensitized solar cells (ssDSSC) constitute a major approach to photovoltaic energy conversion with efficiencies over 8% reported thanks to the rational design of efficient porous metal oxide electrodes, organic chromophores, and hole transporters. Among the various strategies used to push the performance ahead, doping of the nanocrystalline titanium dioxide (TiO 2) electrode is regularly proposed to extend the photo-activity of the materials into the visible range. However, although various beneficial effects for device performance have been observed in the literature, they remain strongly dependent on the method used for the production of the metal o…
Ultrafast luminescence of Ga- and In-doped ZnO ceramics
2021
The work of authors (a-c) was financially supported by Russian Foundation for Basic Research (RFBR, Russia) and the work of the last author (d) had financial support from State Education Development Agency (VIAA, Latvia) . All of that was approved as a result of ERA.Net RUS PLUS 2017 joint call for proposals. Here is the link for the joint call for reference: https://www.eranet-rus.eu/en/196.php .
Upconversion luminescence of Er3 +/Yb3 + and their role in the stabilization of cubic NaLaF4 nanocrystals in transparent oxyfluoride glass ceramics
2018
CC BY-NC-ND
First principles calculations on CeO2 doped with Tb3+ ions
2019
This research was funded by the Latvian Council of Science (under the grant project lzp-2018/1-0147). Authors thank W. Chueh, J. Serra, R. Merkle, A. Popov for fruitful discussions.
Atomic Layer Deposition of Localized Boron- and Hydrogen-Doped Aluminum Oxide Using Trimethyl Borate as a Dopant Precursor
2020
Atomic layer deposition (ALD) of boron-containing films has been mainly studied for use in two-dimensional materials and for B doping of Si. Furthermore, lithium-containing borates show great promi...
Hydrogen-doped cubic diamond and the crystal structure of n-diamond
2011
To understand the crystal structure of n-diamond, a hydrogen-doped (H-doped) diamond model has been investigated using first principles calculations. In particular, hydrogen concentration dependent elastic constants and lattice parameters for the H-doped diamond have been analyzed. Our results indicate that when the hydrogen concentration is less than 19 at.%, the H-doped diamond is mechanically stable. When the hydrogen concentration is about 4 at.%, the optimized lattice parameter, simulated XRD pattern and electronic properties for the H-doped diamond all agree well with the corresponding experimental values of n-diamond. The results imply that the n-diamond is likely to be an H-doped di…
Dopant radial inhomogeneity in Mg-doped GaN nanowires
2018
International audience; Using atom probe tomography, it is demonstrated that Mg doping of GaN nanowires grown by Molecular Beam Epitaxy results in a marked radial inhomogeneity, namely a higher Mg content in the periphery of the nanowires. This spatial inhomogeneity is attributed to a preferential incorporation of Mg through the m-plane sidewalls of nanowires and is related to the formation of a Mg-rich surface which is stabilized by hydrogen. This is further supported by Raman spectroscopy experiments which give evidence of Mg-H complexes in the doped nanowires. A Mg doping mechanism such as this, specific to nanowires, may lead to higher levels of Mg doping than in layers, boosting the po…
Permanent photodoping of plasmonic gallium-ZnO nanocrystals
2020
This work was supported by the Latvian Council of Science in the framework of FLPP (Plasmonic oxide quantum dots for energy saving smart windows, lzp-2018/1-0187). Tanel Käämbre acknowledges financial support for the XPS instrumentation maintenance from the Estonian Centre of Excellence in Research project “Advanced materials and high- technology devices for sustainable energetics, sensorics and nanoelectronics” (TK141).
Synthesis of cubic and hexagonal NaYF4:Er3+
2012
Up-conversion luminescence process, which is related to absorption of several light photons (usually infrared) followed by emission of light in the visible or even ultraviolet spectral regions, has attracted interest of scientists due to its potential practical use in various applications including biolabels, temperature sensors, light sources etc. Although observable in d- and f-ions doped materials, the highest efficiency of up-conversion luminescence is usually attained in lanthanides doped hosts. Among huge variety of materials suitable as up-conversion hosts the most prominent is considered to be NaYF4, both due to its low phonon energy and multisite nature of the crystalline lattice. …