Novel method for synthesis of engineered particulates with thin coatings

1997 ◽  
Vol 501 ◽  
Author(s):  
J. Fitz-Gerald ◽  
R. K. Singh
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
New Technologies ◽  
Laser Wavelength ◽  
Rechargeable Batteries ◽  
Laser Plume ◽  
X Ray ◽  
The Core ◽  
Particulate Coatings ◽  
Core Particles

ABSTRACTParticulate coatings have wide ranging applications in several new technologies such as flatpanel displays, sintering of advanced ceramics, rechargeable batteries, etc. In this paper, we show the feasibility of the pulsed laser ablation technique to make very thin, uniformly distributed and discrete coatings in particulate systems so that the properties of the core particles can be suitably modified. Presently, laser ablation techniques have been primarily applied to deposit thin films on flat substrate materials. To deposit discontinuous particulate coatings, the laser induced plume from the target comes in contact with an agitated bed of core particles (size 1–800μm). The pressure and nature of the background gas (inert or active) controls the cluster size of the particles in the laser plume. Experiments were conducted for laser deposition of silver particles on alumina core particles by excimer laser (wavelength = 248 nm and pulse duration = 25 nanosecond) irradiation of silver targets. The surface coverage and the coating of the film wasf found to depend on the laser parameters (energy density and number of laser pulses) as well as the residence time of the core particles in the plume regime. The films were characterized by wavelength and energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy techniques.

Novel Method for Controlling Nano Thin Coatings on Particulate Materials

1998 ◽  
Vol 526 ◽  
Author(s):  
J. Fitz-Gerald ◽  
S. Pennycook ◽  
H. Gao ◽  
V. Krishnamoorthy ◽  
J. Marcinka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Ablation ◽  
New Technologies ◽  
Nano Particles ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Particulate Coatings ◽  
Core Particles

AbstractParticulate coatings have wide ranging applications in several new technologies such as flat-panel displays, sintering of advanced ceramics, rechargeable batteries, etc. In this paper, we show the feasibility of the pulsed laser ablation technique to make very thin, uniformly distributed and discrete coatings in particulate systems so that the properties of the core particles can be suitably modified. Presently, laser ablation techniques have been primarily applied to deposit thin films on flat substrate materials. To deposit discontinuous particulate coatings, the laser induced plume from the target comes in contact with an agitated bed of core particles. The pressure and nature of the background gas (inert or active) controls the cluster size of the nano particles in the laser plume. Experiments were conducted for laser deposition of Ag nano particles on Al2O3 and SiO2 core particles by pulsed excimer laser (wavelength = 248 nm and pulse duration = 25 nanosecond) irradiation of a Ag sputtering target The surface coverage and coating uniformities of the film were found to depend on the synthesis parameters (energy density, # laser pulses, gas pressure backfill gas, molecular weight) as well as the residence time of the core particles in the plume regime. The films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), wavelength dispersive x-ray analysis (WDX), scanning transmission electron microscopy (STEM), and x-ray photoelectron spectroscopy (XPS).

Studies of Carbon Nitride Thin Films Synthesized by KrF Excimer Ablation of Graphite in Nitrogen Atmosphere

1998 ◽  
Vol 526 ◽  
Author(s):  
Z.M. Ren ◽  
Y.F. Lu ◽  
W.D. Song ◽  
D.S.H. Chan ◽  
T.S. Low ◽  
...  
Keyword(s):  
Thin Films ◽  
Excimer Laser ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Nitrogen Pressure ◽  
Laser Wavelength ◽  
Nitrogen Atmosphere ◽  
Amorphous Semiconductor ◽  
X Ray ◽  
Krf Excimer Laser

AbstractCarbon nitride thin films were deposited on silicon wafers by pulsed KrF excimer laser (wavelength 248 nm, duration 23 ns) ablation of graphite in nitrogen atmosphere. Different fluences of the excimer laser and pressures of the nitrogen atmosphere were used in order to achieve a high nitrogen content in the deposited thin films. Fourier Transform Infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to identify the binding structure and the content of the nitrogen species in the deposited thin films. The highest N/C ratio 0.42 was achieved at an excimer laser fluence of 0.8 Jcm -2with a repetition rate of 10 Hz under the nitrogen pressure of PN=100 mTorr. A high content of C=N double bond instead of C-N triple bond was indicated in the deposited thin films. Ellipsometry was used to analyze the optical properties of the deposited thin films. The carbon nitride thin films have amorphous-semiconductor-like characteristics with the optical band gap Eop, as high as 0.42 eV.

Laser Induced Decomposition of Triethylgallium and Trimethylgallium Adsorbed on GaAs(100)

1988 ◽  
Vol 129 ◽  
Author(s):  
J. A. Mccaulley ◽  
V. R. Mccrary ◽  
V. M. Donnelly
Keyword(s):  
Excimer Laser ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Electronic Excitation ◽  
Removal Rate ◽  
Laser Wavelength ◽  
High Fluence ◽  
X Ray ◽  
Two Photon ◽  
Induced Decomposition

ABSTRACTWe report X-ray photoelectron spectroscopy (XPS) studies of excimer laser stimulated decomposition of triethylgallium (TEGa) and trimethylgallium (TMGa) adsorbed on Gastabilized GaAs(100) surfaces in ultrahigh vacuum. TEGa and TMGa dissociatively chemisorb on GaAs at room temperature, whereupon irradiation by an excimer laser (at 193 or 351 nm) leads to further dissociation and desorption of carbon-containing species. The carbon removal rate (per laser pulse) decreases as carbon is removed suggesting multiple reaction sites, coverage dependent Arrhenius parameters, or second-order reactions. Based on the dependence of the rate on laser wavelength and fluence, we conclude that at low fluence, a two-photon electronic excitation of the adsorbate occurs, while at high fluence, laser induced pyrolysis dominates.

Chemical structure of films grown by AlN laser ablation: an X-ray photoelectron spectroscopy study

1999 ◽  
Vol 122 (2-3) ◽  
pp. 242-246 ◽  
Author(s):  
N. Laidani ◽  
L. Vanzetti ◽  
M. Anderle ◽  
A. Basillais ◽  
C. Boulmer-Leborgne ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Spectroscopy Study ◽  
X Ray

X‐ray photoelectron spectroscopy of carbon nitride films deposited by graphite laser ablation in a nitrogen postdischarge

1996 ◽  
Vol 69 (12) ◽  
pp. 1698-1700 ◽  
Author(s):  
Malek Tabbal ◽  
Philippe Mérel ◽  
Simona Moisa ◽  
Mohamed Chaker ◽  
André Ricard ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
X Ray

An X-Ray Photoelectron Spectroscopic Study of the Free Surface Segregation of Impurities in Platinum and Palladium

1987 ◽  
Vol 41 (3) ◽  
pp. 516-522
Author(s):  
Alan J. Paul ◽  
Peter M. A. Sherwood
Keyword(s):  
Free Surface ◽  
Spectroscopic Study ◽  
Photoelectron Spectroscopy ◽  
Surface Segregation ◽  
Pure Metal ◽  
Binding Energies ◽  
X Ray ◽  
The Core ◽  
Segregation Of Impurities ◽  
Elemental Form

X-ray photoelectron spectroscopy has been used to observe the free surface segregation of impurities in samples of platinum and palladium. Heating in vacuo to 600°C promoted the surface segregation of silver, gold, and carbon in platinum and the surface segregation of silver and sulfur in palladium. All species segregated in their elemental form. The core level binding energies of the silver and gold segregants were lower than those measured for the corresponding pure metal states.

scholarly journals Polyether-Based Supramolecular Electrolytes With Two-Dimensional Boroxine Skeleton

2021 ◽  
Vol 9 ◽  
Author(s):  
Masahiro Yoshizawa-Fujita ◽  
Shunsuke Horiuchi ◽  
Tamao Uemiya ◽  
Jun Ishii ◽  
Yuko Takeoka ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Linear Sweep Voltammetry ◽  
Transference Number ◽  
Rechargeable Batteries ◽  
Solid Polymer Electrolytes ◽  
Solid Polymer ◽  
Two Dimensional ◽  
X Ray ◽  
Number Of Cycles

Solid polymer electrolytes mainly based on polyethers have been actively investigated for over 40 years to develop safe, light, and flexible rechargeable batteries. Here, we report novel supramolecular electrolytes (SMEs) composed of polyether derivatives and a two-dimensional boroxine skeleton synthesized by the dehydration condensation of 1,4-benzenediboronic acid in the presence of a polyether with amines on both chain ends. The formation of SMEs based on polyether derivatives and boroxine skeleton was confirmed by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were performed to evaluate the electrochemical stability and lithium conductive properties of SMEs with given amounts of lithium bis(trifluoromethylsulfonyl)amide (LiTFSA). The ionic conductivity of SME/LiTFSA composites increased with increasing lithium-salt concentration and reached a maximum value at a higher concentration than those of simple polyether systems. The lithium-ion transference number (tLi+) of SME/LiTFSA was higher than those of polyether electrolytes. This tendency is unusual for a polyether matrix. SME/LiTFSA composite electrolytes exhibited a stable lithium plating/striping process even after 100 cycles. The current density increased with an increasing number of cycles. The combination of ion conductive polymers and a two-dimensional boroxine skeleton will be an interesting concept for developing solid electrolytes with good electrochemical properties.

scholarly journals Structure and Ferromagnetism in Carbon Nanofibers from PAN/PVP

2021 ◽  
Author(s):  
Suminya - Teeta ◽  
Somchai - Sonsupap ◽  
Ratchaneekorn - Wanchanthuek ◽  
Santi - Maensiri ◽  
Narong - Chanlek ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Carbon Nanofibers ◽  
Chemical Bonding ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
New Technologies ◽  
Room Temperature Ferromagnetism ◽  
Weight Ratio ◽  
Average Diameter ◽  
X Ray

Abstract We report on the room-temperature ferromagnetism in carbon nanofibers. Carbon nanofibers were fabricated using sequential electrospinning of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP). The morphologies, crystal structures, chemical bonding states and magnetic properties were characterized for three different polyacrylonitrile (PAN) to polyvinylpyrrolidone (PVP) weight ratios (10:0, 7:3 and 6:4) of PAN/PVP. The as-spun PAN/PVP were carbonized in three steps; stabilization, carbonization and activation at 800 ºC to obtain carbon nanofibers. The morphology and structure of the carbon nanofibers (CNFs) were completely characterized by field emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD) and Raman spectroscopy. The elemental composition and the chemical bonding of CNFs were analyzed by x-ray photoelectron spectroscopy (XPS), the magnetic properties of CNFs were measured by vibrating sample magnetometer (VSM) at room-temperature. XRD patterns showed the phase of amorphous carbon structure. The average diameter sizes of the carbon nanofibers ranged from 340 to 484 nm. Raman analysis was used to determine the carbon qualities in the samples by the numbers of sp3/sp2 hybridized atoms. Chemical analysis with XPS indicated that there were no magnetic contaminants in the samples. The PAN/PVP weight ratio of 6:4 showed ferromagnetic carbon nanofibers with the highest specific magnetization as ~144.2 memu/g at 300 K. These results inspire us to further research the potential of carbon materials, as a completely new class of magnetic devices. This will aid the development of new technologies in the near future.

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