Synthesis of Nanophase Noble Metal Systems Utilizing Porous Silicon

1996 ◽  
Vol 457 ◽  
Author(s):  
I. Coulthard ◽  
T. K. Sham
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Porous Silicon ◽  
Noble Metal ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Visible Range ◽  
X Ray ◽  
Metallic Salt ◽  
Scanning Electron

ABSTRACTApart from its well known ability to luminesce very intensely at room temperature in the visible range, porous silicon is also an effective reducing agent. We report the formation of several noble metal (Pd, Ag, Au, Pt) nanostructures by reductive dispersion of metal ions from aqueous solutions onto the surface of porous silicon. The nanophase systems produced by reductive deposition vary with the element deposited and the metallic salt utilized in the process. The resulting nanophase systems were studied using a variety of techniques including: scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and spectroscopie methods using synchrotron radiation.

scholarly journals Получение нанокомпозитов МУНТ/MnO-=SUB=-2-x-=/SUB=-, МУНТ/MnO-=SUB=-2-x-=/SUB=-/CuO и исследования их газочувствительных свойств

2019 ◽  
Vol 61 (11) ◽  
pp. 2240
Author(s):  
Ю.А. Стенькин ◽  
В.В. Болотов ◽  
Д.В. Соколов ◽  
В.Е. Росликов ◽  
К.Е. Ивлев
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Gas Sensing ◽  
Multiwalled Carbon ◽  
X Ray ◽  
P Type ◽  
Scanning Electron

Nanocomposites based on multiwalled carbon nanotubes (MWCNT) with manganese dioxide (MnO2-x) and copper oxide (CuO) were obtained and investigated. The morphology and elemental composition of MWCNT-layer and nanocomposites MWCNT/MnO2-х, MWCNT/MnO2-х/CuO were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing response of MWCNT-layer and nanocomposites upon exposure to hydrogen sulfide (H2S) and nitrogen dioxide (NO2) was demonstrated at room temperature. Effect of increasing the conductivity of MWCNT-layer and nanocomposites upon exposure to NO2 indicates these nanomaterials have conductive of p-type. Copper oxide in nanocomposite significantly enhances the gas sensing response to H2S.

scholarly journals Investigation of Spin Coating Cerium-Doped Hydroxyapatite Thin Films with Antifungal Properties

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 464
Author(s):  
Simona Liliana Iconaru ◽  
Mihai Valentin Predoi ◽  
Patrick Chapon ◽  
Sofia Gaiaschi ◽  
Krzysztof Rokosz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Spin Coating ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
X Ray ◽  
Antifungal Properties ◽  
Scanning Electron

In this study, the cerium-doped hydroxyapatite (Ca10−xCex(PO4)6(OH)2 with xCe = 0.1, 10Ce-HAp) coatings obtained by the spin coating method were presented for the first time. The stability of the 10Ce-HAp suspension particles used in the preparation of coatings was evaluated by ultrasonic studies, transmission electron microscopy (TEM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The surface morphology of the 10Ce-HAp coating was studied by SEM and atomic force microscopy (AFM) techniques. The obtained 10Ce-HAp coatings were uniform and without cracks or unevenness. Glow discharge optical emission spectroscopy (GDOES) and X-ray photoelectron spectroscopy (XPS) were used for the investigation of fine chemical depth profiling. The antifungal properties of the HAp and 10Ce-HAp suspensions and coatings were assessed using Candida albicans ATCC 10231 (C. albicans) fungal strain. The quantitative antifungal assays demonstrated that both 10Ce-HAp suspensions and coatings exhibited strong antifungal properties and that they successfully inhibited the development and adherence of C. albicans fungal cells for all the tested time intervals. The scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) visualization of the C. albicans fungal cells adherence to the 10Ce-HAp surface also demonstrated their strong inhibitory effects. In addition, the qualitative assays also suggested that the 10Ce-HAp coatings successfully stopped the biofilm formation.

ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Uv Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition And Structure ◽  
Light Excitation ◽  
Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Spontaneous Formation ◽  
The Stability ◽  
Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

N-type Ba0.2Co4Sb11.5Te0.5: Optimization of thermoelectric properties by different pressures

2019 ◽  
Vol 33 (03) ◽  
pp. 1950027 ◽  
Author(s):  
Jiaxiang Chen ◽  
Xiaopeng Jia ◽  
Yuewen Zhang ◽  
Haiqiang Liu ◽  
Baomin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Absolute Value ◽  
X Ray ◽  
Coefficient Increase ◽  
Maximum Power Factor ◽  
Scanning Electron

The polycrystalline skutterudite [Formula: see text] were successfully synthesized from 1.5 GPa to 3.5 GPa by the high pressure and high temperature (HPHT) method. Negative Seebeck coefficient confirmed the n-type conductivity of all samples. The phase compositions of samples were investigated by X-ray diffraction (XRD) and the microstructures were observed by scanning electron microscopy (SEM). It was found that the grains appeared smaller and the grain boundaries became more abundant when pressures were higher. We measured the electrical properties from room temperature to 723 K. Both the electrical resistivity and absolute value of Seebeck coefficient increase with the increasing synthetic pressure. At 723 K, the maximum power factor of [Formula: see text] was obtained for the sample synthesized under 3 GPa. The maximum ZT value of 0.61 was reached by [Formula: see text] synthesized under 3 GPa and measured at 723 K.

scholarly journals Improvement of the Space Charge Suppression and Hydrophobicity Property of Cellulose Insulation Pressboard by Surface Sputtering a ZnO/PTFE Functional Film

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1610 ◽  
Author(s):  
Li ◽  
Hao ◽  
Zhang ◽  
Hou ◽  
Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Space Charge ◽  
Photoelectron Spectroscopy ◽  
Power Transformers ◽  
Nano Structure ◽  
X Ray ◽  
Ptfe Composite ◽  
Cellulose Insulation ◽  
Scanning Electron

Oil-impregnated cellulose insulation polymer (oil-paper/pressboard insulation) has been widely used in power transformers. Establishing effective ways of improving the physical and chemical properties of the cellulose insulation polymer is currently a popular research topic. In order to improve the charge injection inhibition and hydrophobic properties of the cellulose insulation polymer used in power transformers, nano-structure zinc oxide (ZnO) and polytetrafluoroethylene (PTFE) films were fabricated on a cellulose insulation pressboard surface via reactive radio frequency (RF) magnetron sputtering. Before the fabrication of their composite film, Accelrys Materials Studio (MS) software was applied to simulate the interaction between the nanoparticles and cellulose molecules to determine the depositing sequence. Simulation results show that the ZnO nanoparticle has a better adhesion strength with cellulose molecules than the PTFE nanoparticle, so ZnO film should be sputtered at first to fabricate the ZnO/PTFE composite film for better film quality. The sputtered, thin films were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The space charge injection behavior and the hydrophobicity performance of the untreated pressboard; and the cellulose insulation pressboard with sputtered nano-structure ZnO, PTFE, and the ZnO/PTFE functional films were compared with each other. X-ray photoelectron spectroscopy results showed that ZnO, PTFE, and ZnO/PTFE functional films were all successfully fabricated on the cellulose insulation pressboard surface. Scanning electron microscopy and XRD results present the nano-structure of the sputtered ZnO, PTFE, and ZnO/PTFE functional films and their amorphous states, respectively. The ZnO/PTFE composite functional film shows an apparent space charge suppression effect and hydrophobicity. The amount of the accumulated space charge in the pressboard sputtered ZnO/PTFE composite functional film decreased by about 40% compared with that in untreated cellulose insulation pressboard, and the water contact angle (WCA) increased from 0° to 116°.

Characterization of Multiple Functional Solid Line of Graphite Ink Surface Printed by Micro-Flexographic

2015 ◽  
Vol 752-753 ◽  
pp. 1379-1383
Author(s):  
M.I. Maksud ◽  
Mohd Sallehuddin Yusof ◽  
Zaidi Embong
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Printing Plate ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Flexographic Printing ◽  
Scanning Electron

The purpose of this paper is to study a ink surface morphology, quantify the chemical composition involved in processing of graphite ink printed by flexographic printing. The methodology is to use surface sensitive technique, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). As a finding we successfully achieved 25 micron lines array using PDMS printing plate. The Originality and value of this work is surface sensitive techniques like XPS, AFM and FESEM were exclusively used in order to characterize graphite inks printed by flexographic method, using PDMS printing plate.

scholarly journals Preparation of Cerium Dioxide Layers on Titanium by Electrodeposition with Organic Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Vaijayanti Namdeo Nande ◽  
Diana Kostyukova ◽  
Jeonghee Choi ◽  
Yong Hee Chung
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Cerium Dioxide ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Organic Solution ◽  
X Ray ◽  
Titanium Foils ◽  
Scanning Electron

Layers of cerium dioxide nanoparticles were prepared on titanium by electrodeposition with organic solution. Three concentrations of cerium ions were used at 31.6 V. The organic solution was isobutanol and titanium foils were used as anodes and cathodes. Currents were monitored during the electrodeposition. Deposition times ranged from 0.5 to 8 h. Deposited Deposited layers were calcined at 700 K for 30 min. The morphology and composition of the deposited layers were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). As-prepared and calcined deposition layers were assayed to be cerium dioxide. The average crystallite size increased from 4 to 7 nm through calcination at 700 K. Sizes of calcined cerium oxide agglomerates were ranging from 73 to 146 nm for 30 min deposition and 209 to 262 nm for 8 h deposition. The electrodeposition efficiencies of 0.5 h deposition at three concentrations were measured to be highest.

scholarly journals Preparation and Phase Relations in the CuSbSe2 – CuInSe2 System

2016 ◽  
Vol 1735 ◽  
Author(s):  
Barys V. Korzun ◽  
Valery R. Sobol ◽  
Marin Rusu ◽  
Ruben M. Savizky ◽  
Alena A. Fadzeyeva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Mole Fraction ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Phase Relations ◽  
X Ray ◽  
Ternary Compounds ◽  
Scanning Electron

ABSTRACTThe CuInSe2 and CuSbSe2 ternary compounds and alloys of the (CuSbSe2)1-x·(CuInSe2)x system with the mole fraction of CuInSe2 (x) equal to 0.05, 0.15, 0.25, 0.375, 0.50, 0.625, 0.75, 0.85, and 0.95 were prepared and the phase relations in this system were investigated by X-ray powder diffraction, optical microscopy, and scanning electron microscopy. It was shown that the alloys of the CuSbSe2-CuInSe2 system are biphasic at room temperature in the whole range of compositions, and the limits of solubility for CuSbSe2 in CuInSe2 and for CuInSe2 in CuSbSe2 do not exceed 0.001 mole fraction.

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Analytical Techniques ◽  
Heating Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

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