L. Erades

Bio: L. Erades is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Tin oxide & Extended X-ray absorption fine structure. The author has an hindex of 6, co-authored 10 publications receiving 466 citations.

Synthesis of Indium and Indium Oxide Nanoparticles from Indium Cyclopentadienyl Precursor and Their Application for Gas Sensing

Abstract: Decomposition of the organometallic precursor [In(η5-C5H5)] in toluene in the presence of methanol (8 vol.-%) at room temperature leads to the immediate formation of aggregates of indium nanoparticles of 15 ± 2 nm mean diameter. The aggregates are roughly spherical with a mean size of 400 ± 40 nm. The particles were characterized by means of transmission electron and high-resolution transmission electron microscopies (TEM and HRTEM), and X-ray diffraction (XRD) studies indicate that the powder consists of the tetragonal phase of indium. The thermal oxidation in air of these nanoparticles yields well-crystallized nanoparticles of In2O3 with unchanged morphology (aggregates of nanoparticles of 16.6 ± 2 nm mean diameter with aggregate mean size of 400 ± 40 nm) and without any sign of coalescence. XRD pattern shows that the powder consists of the cubic phase of In2O3. The electrical conductivity measurements demonstrate that this material is highly sensitive to an oxidizing gas such as nitrogen dioxide and barely sensitive to a reducing gas such as carbon monoxide. Its association with SnO2-based sensors allows the selective detection of carbon monoxide (30 ppm) and sub-ppm amounts of nitrogen dioxide (400 ppb) in a mixture at 21 °C and at a relative humidity of 60 %.

Shape Control of Platinum Nanoparticles

Abstract: The synthesis of shape controlled platinum nanoparticles has been investigated through an organometallic approach starting from the complex Pt 2 (dba) 3 and using a long alkyl chain amine, hexadecylamine (HDA), as stabilizer The influence of the experimental parameters (reactive gas and solvent nature, stabilizer/metal ratio, reactants concentration, temperature) on the shape of the Pt nanoparticles has been studied Various shaped platinum nanostructures such as isolated nanoparticles, dendrites or crystalline nanowires were obtained, depending on the reaction conditions This method takes profit of the mild conditions of chemistry in solution and allows obtaining regular nanostructures, most of them being homogeneous in shape as well as in size (isolated nanoparticles) or diameter/length (nanowires) Transmission electron microscopy and wide-angle X-ray scattering were used as characterization techniques Beside the Knight-shift effect of platinum, NMR solution investigations clearly evidenced the coordination of the amine at the Pt particles surface and its mobility This mobility, increased when H 2 is used as reactive gas for the precursor decomposition, favors the particles coalescence into nanowires This phenomenon is also favored by the "soft" template character of the amine in particular in toluene solution

CO response of a nanostructured SnO2 gas sensor doped with palladium and platinum

Abstract: In this paper, we show the influence of humidity on the sensitivity for CO sensing of the nanoparticular SnO 2 sensors at an operating temperature of 450 ◦ C. Three different sensors have been studied: un-doped sensors and doped sensors with two doping agents palladium and platinum. It is well known that the resistance of the sensitive layer is largely modified by doping. This study demonstrates that un-doped sensors show under CO a sensitivity less important in humid air than in dry air. Doped sensors display a very different behavior. Indeed, in dry air, a high sensitivity is observed, characterized by an increase in the resistance of the sensitive layer whereas in humid air (>10% RH) a high sensitivity is also observed but characterized by a decrease in the resistance of the sensitive layer. In between, a point of zero sensitivity is found. These results carry out the presence of unexpectedly different electrochemical operating mode for CO sensing according to the humidity content. © 2004 Elsevier B.V. All rights reserved.

Nanosized tin oxide sensitive layer on a silicon platform for domestic gas applications

Abstract: Micromachined silicon platforms have been specially created to be coated with a drop of tin oxide sensitive layer. Design of the silicon substrate includes a thin dielectric membrane for mechanical and thermal insulation purpose. A passivation layer covers the silicon front side structures except bonding pads and sensitive layer contacts and allows an easy drop deposition (no short circuit risk with heater electrode). The deposition material is a suspension of tin dioxide nanoparticles mixed in a solvent. A novel drop deposition technique is used and first characterizations under CO and CH4 gases are related and show high sensitivity and reliability level.

Recent advances in the liquid-phase syntheses of inorganic nanoparticles.

Abstract: The development of novel materials is a fundamental focal point of chemical research; and this interest is mandated by advancements in all areas of industry and technology. A good example of the synergism between scientific discovery and technological development is the electronics industry, where discoveries of new semiconducting materials resulted in the evolution from vacuum tubes to diodes and transistors, and eventually to miniature chips. The progression of this technology led to the development * To whom correspondence should be addressed. B.L.C.: (504) 2801385 (phone); (504) 280-3185 (fax); bcushing@uno.edu (e-mail). C.J.O.: (504)280-6846(phone);(504)280-3185(fax);coconnor@uno.edu (e-mail). 3893 Chem. Rev. 2004, 104, 3893−3946

Gas sensors using hierarchical and hollow oxide nanostructures: Overview

Abstract: Hierarchical and hollow oxide nanostructures are very promising gas sensor materials due to their high surface area and well-aligned nanoporous structures with a less agglomerated configurations. Various synthetic strategies to prepare such hierarchical and hollow structures for gas sensor applications are reviewed and the principle parameters and mechanisms to enhance the gas sensing characteristics are investigated. The literature data clearly show that hierarchical and hollow nanostructures increase both the gas response and response speed simultaneously and substantially. This can be explained by the rapid and effective gas diffusion toward the entire sensing surfaces via the porous structures. Finally, the impact of highly sensitive and fast responding gas sensors using hierarchical and hollow nanostructures on future research directions is discussed.

Method for making electronic devices using metal oxide nanoparticles

Abstract: A method of making a thin film transistor comprises (a) solution depositing a dispersion comprising semiconducting metal oxide nanoparticles onto a substrate, (b) sintering the nanoparticles to form a semiconductor layer, and (c) optionally subjecting the resulting semiconductor layer to post-deposition processing.