Search results for "substrate"
showing 10 items of 1018 documents
Luminescence of phosphorus doped silica glass
2017
This work is supported by Material Science program IMIS2 of Latvia.
Energy scales and dynamics of electronic excitations in functionalized gold nanoparticles measured at the single particle level.
2019
The knowledge of the electronic structure and dynamics of nanoparticles is a prerequisite to develop miniaturized single-electron devices based on nanoparticles. Low-temperature transport measurements of individual stable metallic nanoparticles enable unravelling the system specific electronic structure while ultrafast optical spectroscopy gives access to the electron dynamics. In this work, we investigate bare and thiol-functionalized gold nanoparticles. For the latter, we employ a fast and low-cost fabrication technique which yields nanoparticles with narrow size distribution. Using relatively long thiol-ended alkane chains for the functionalization modifies the electronic density of stat…
Blue-luminescent organic lead bromide perovskites: highly dispersible and photostable materials
2015
The preparation of a blue-luminescent and photostable organic–inorganic hybrid perovskite with an X-ray powder diffraction spectrum consistent with a two-dimensional inorganic framework is reported. This perovskite can be produced with a high reaction yield and valuable optical properties, such as luminescence quantum yield over 20%, radiative rate constant of up to 80 × 106 s−1, and high photostability under UV light. This material remains stable as a solid, is toluene-dispersible, and can be reverted reversibly into its precursors by using dimethylformamide (DMF). Moreover, the DMF dispersion can be injected into toluene to produce a nanomaterial or be used to prepare films by spin-coatin…
Valorisation of urban green areas for producing renewable energy and biochar as growing substrate of Sicilian aromatic and nutraceutical species in a…
2020
This work is aimed at evaluating the possible building up of a gasifier for the energy valorisation of residual biomass deriving from urban areas and their surroundings. The area and the volumes of supply and economic convenience have been determined by implementing a GIS-based geographic method to the localisation and quantification of non-uniform elements of plant biomass. The pyrolysis and gasification processes of the lignocellulosic biomass obtained from pruning and maintenance operations of the urban and ornamental green include the production of a residual amount of biochar. The biochar can be used in agriculture as a soil improver and a substrate alternative to peat in the sustainab…
Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition
2013
Different ZnO nanostructured films were electrochemically grown, using an aqueous solution based on ZnCl2, on three types of transparent conductive oxides grow on commercial ITO (In2O3:Sn)-covered glass substrates: (1) ZnO prepared by spin coating, (2) ZnO prepared by direct current magnetron sputtering, and (3) commercial ITO-covered glass substrates. Although thin, these primary oxide layers play an important role on the properties of the nanostructured films grown on top of them. Additionally, these primary oxide layers prevent direct hole combination when used in optoelectronic devices. Structural and optical characterizations were carried out by scanning electron microscopy, atomic for…
Growth, structural and optical properties of AlGaN nanowires in the whole composition range.
2013
International audience; We report on the growth of AlxGa1-xN nanowires by plasma-assisted molecular beam epitaxy for x in the 0.3-0.8 range. Based on a combination of macro- and micro-photoluminescence, Raman spectroscopy, x-ray diffraction and scanning electron microscopy experiments, it is shown that the structural and optical properties of AlGaN NWs are governed by the presence of compositional fluctuations associated with strongly localized electronic states. A growth model is proposed, which suggests that, depending on growth temperature and metal adatom density, macroscopic composition fluctuations are mostly of kinetic origin and are directly related to the nucleation of the AlGaN na…
Smart polymeric coatings for damage visualization in substrate materials
2012
For damage indication needs in polymer composites, three smart acrylic coatings based on microencapsulated crystal violet lactone leuco dye with embedded developer silica gel and methyl 4-hydroxybenzoate were elaborated. Damage visualization ability upon duralumin substrates was tested. Indentation tests were conducted in the interval of 0.0005–0.55 J of mechanical work. Digital image analysis was used for evaluation of the visual response in the form of “bruise” spots. The measure of response intensity was relative excess of blue color above achromatic gray in the scanned images of the “bruise” spots. This technique allowed detecting influence of the coating formulations onto the substrat…
Influence of Substrate Hydrophilicity on Structural Properties of Supported Lipid Systems on Graphene, Graphene Oxides, and Silica
2021
Pristine graphene, a range of graphene oxides, and silica substrates were used to investigate the effect of surface hydrophilicity on supported lipid bilayers by means of all-atom molecular dynamics simulations. Supported 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers were found in close-contact conformations with hydrophilic substrates with as low as 5% oxidation level, while self-assembled monolayers occur on pure hydrophobic graphene only. Lipids and water at the surface undergo large redistribution to maintain the stability of the supported bilayers. Deposition of bicelles on increasingly hydrophilic substrates shows the continuous process of reshaping of the supported system a…
Chemical characterization of gallium droplets grown by LP-MOCVD.
2006
International audience; This study is concerned with the chemical characterization of metallic gallium droplets, obtained on silicon (1 0 0) substrates with a single growth step, by the LP-MOCVD technique with TMGa like precursor. These structures are characterized by SIMS, XPS and TEM. The analyses results lead to a structure proposition for the droplets. The core is composed of metastable metallic gallium with a non-negligible carbon quantity probably coming from incomplete precursor decomposition. The outer part, composed of gallium oxide maintains the structure stability. Covering of the substrate by a thin gallium layer of gallium compounds is observed.
Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO2 nanoparticles on a Si substrate
2017
Financial support from the Estonian Research Council (IUT2-25, PUT170, PUT1096, PUT748, PUTJD680), the Estonian Centre of Excellence in Research Projects “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” TK141 (2014-2020.4.01.15-0011), “Emerging orders in quantum and nanomaterials” TK134 and the Development Fund of the University of Tartu, are all gratefully acknowledged.