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Carbon Thin Films (carbon + thin_film)
Selected AbstractsEffect of Platinum and Ruthenium Incorporation on Voltammetric Behavior of Nitrogen Doped Diamond-Like Carbon Thin FilmsELECTROANALYSIS, Issue 23 2009W. Khun Abstract Nitrogen doped diamond-like carbon thin films with or without platinum and ruthenium incorporation (N-DLC or PtRuN-DLC) were deposited on highly conductive p-Si substrates by DC magnetron sputtering to study the effect of Pt and Ru doping on the voltammetric performance of the N-DLC films. The potential windows of these film electrodes were measured in different electrolytic solutions, such as H2SO4, HCl and KCl. The cyclic voltammograms obtained from the N-DLC film electrodes in these solutions showed wide potential windows while the introduction of Pt and Ru into the film electrodes apparently narrowed down the potential windows due to their catalytic activities. [source] Aqueous Lithium-ion Battery LiTi2(PO4)3/LiMn2O4 with High Power and Energy Densities as well as Superior Cycling Stability**,ADVANCED FUNCTIONAL MATERIALS, Issue 18 2007J.-Y. Luo Abstract Porous, highly crystalline Nasicon-type phase LiTi2(PO4)3 has been prepared by a novel poly(vinyl alcohol)-assisted sol,gel route and coated by a uniform and continuous nanometers-thick carbon thin film using chemical vapor deposition technology. The as-prepared LiTi2(PO4)3 exhibits excellent electrochemical performance both in organic and aqueous electrolytes, and especially shows good cycling stability in aqueous electrolytes. An aqueous lithium-ion battery consisting of a combination of LiMn2O4 cathode, LiTi2(PO4)3 anode, and a 1 M Li2SO4 electrolyte has been constructed. The cell delivers a capacity of 40 mA,h,g,1 and a specific energy of 60 W,h,kg,1 with an output voltage of 1.5 V based on the total weight of the active electrode materials. It also exhibits an excellent cycling stability with a capacity retention of 82,% over 200 charge/discharge cycles, which is much better than any aqueous lithium-ion battery reported. [source] Effect of Platinum and Ruthenium Incorporation on Voltammetric Behavior of Nitrogen Doped Diamond-Like Carbon Thin FilmsELECTROANALYSIS, Issue 23 2009W. Khun Abstract Nitrogen doped diamond-like carbon thin films with or without platinum and ruthenium incorporation (N-DLC or PtRuN-DLC) were deposited on highly conductive p-Si substrates by DC magnetron sputtering to study the effect of Pt and Ru doping on the voltammetric performance of the N-DLC films. The potential windows of these film electrodes were measured in different electrolytic solutions, such as H2SO4, HCl and KCl. The cyclic voltammograms obtained from the N-DLC film electrodes in these solutions showed wide potential windows while the introduction of Pt and Ru into the film electrodes apparently narrowed down the potential windows due to their catalytic activities. [source] Silica-Templated Continuous Mesoporous Carbon Films by a Spin-Coating Technique ,ADVANCED MATERIALS, Issue 11 2004J. Pang Continuous mesoporous carbon thin films (see Figure) have been synthesized through direct carbonization of sucrose/silica nanocomposite films and subsequent removal of the silica to create a mesoporous carbon network. This method provides a simple and efficient method to synthesize continuous, high surface area and pore volume mesoporous carbon thin films with uniform-sized and interconnected pore channels. [source] Endothelial cell growth on silicon modified hydrogenated amorphous carbon thin filmsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008A. A. Ogwu Abstract The biological response of human microvascular endothelial cells (HMEC-1) seeded on Si-DLC films and on control surfaces was evaluated in terms of initial cell enhancement, growth, and cytotoxicity. The microstructure of the films was characterised by Raman spectroscopy and X-ray photoelectron spectroscopy. The effect of changes in microstructure, surface energy, surface electronic state, and electronic conduction, on the biological response of the films to endothelial cells was investigated. Endothelial cell adhesion and growth was found to be affected by changes in the microstructure of the films induced by silicon doping and thermal annealing. We observed a significant statistical difference in endothelial cell count between the as-deposited DLC and Si-DLC films using the one sample t -test at a p -value of 0.05. We also found a statistically significant difference between the adhesion of HMEC films on DLC and Si-DLC films at various annealing temperatures using the one-way ANOVA F statistic test at p < 0.05 and the post-hoc Tukey test. One sample t -test at p < 0.05 of MTT-assay results showed the endothelial cells to be viable when seeded on DLC/Si-DLC films. We suspect that the increased adhesion of endothelial cells induced by increasing the amount of silicon in the Si-DLC films is associated with the development of a suitable surface energy due to silicon addition, which neither favored cell denaturing nor preferential water spreading before cellular attachment on the film surface. The presence of an external positively charged dipole on the Si-DLC films confirmed by our Kelvin probe measurements is also expected to enhance the adhesion of endothelial cells that are well known to carry a negative charge. The Si-DLC films investigated hold potential promise as coatings for haemocompatible artificial implants. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Ultraviolet and visible Raman spectroscopic investigations of nanocrystalline carbon thin films grown by bias-assisted hot-filament chemical vapor depositionJOURNAL OF RAMAN SPECTROSCOPY, Issue 3 2003S. Gupta Abstract The structural bonding in a series of nanocrystalline carbon thin films grown under different substrate biasing conditions was analyzed using Raman spectroscopy in both the visible and ultraviolet (uv) regimes of the spectrum. The nanocrystalline carbon thin films studied were deposited by the hot-filament chemical vapor deposition (HFCVD) technique using a 2% concentration of methane in hydrogen. The films were deposited on molybdenum substrates under various substrate biasing conditions. A positive bias (forward) produced a continuous flow of electrons from the filament on to the substrate, whereas a negative bias (negative) caused the substrate to be bombarded with positive ions. Films were also grown under no bias, for comparison. Differences in the Raman spectra obtained with visible (,L = 514.5 nm) and uv (,L = 244.0 nm) excitation sources were investigated. Apart from the basic features consisting of D and G bands at around 1360 and 1580 cm,1 in the case of visible Raman spectra, an extra feature at around 1060 cm,1, denoted a T band, appeared in the uv Raman spectra only. Hence, uv Raman scattering measurements clearly revealed the presence of sp3 -bonded carbon atoms. The position and its intensity ratio with respect to the G peak [(I(T)/I(G)] were used to provide a reliable means to measure the sp3 C bonding fraction, which is both semi-quantitative and non-destructive. The sp3 content estimated within the microstructure of n-C thin films was found to be around 60,80%. Further, probing the samples with two different photons (visible and uv) allowed us to estimate qualitatively the amount and clustering of sp2 sites. This technique provided a fast and reliable microstructural characterization of disordered carbons. The dispersion in the Raman features is specific to each carbon system and, therefore, can be used as a fingerprint. These findings point at the similarities of bias-assisted HFCVD nanocrystalline carbon (n-C) materials and the tetrahedrally bonded amorphous carbon (ta -C) materials grown by ion-beam assisted deposition (IBAD). Copyright © 2003 John Wiley & Sons, Ltd. [source] | |||||||||||||