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Publications (281)
The ability to have predictive behavior of nanoparticles during bottom-up fabrication requires a fundamental understanding of their mechanical properties, often differing from their bulk counterparts because of the dramatic difference in grain size and free surfaces. Here, a series of in situ nanocompression experiments is performed on cerium oxide...
Correlating the microstructure of an energy conversion device to its performance is often a complex exercise, notably in solid oxide fuel cell research. Solid oxide fuel cells combine multiple materials and interfaces that evolve in time due to high operating temperatures and reactive atmospheres. We demonstrate here that operando environmental tra...
Correlating the microstructure of an energy conversion device to its performance is often a complex exercise, notably in solid oxide fuel cell (SOFC) research. SOFCs combine multiple materials and interfaces that evolve in time due to high operating temperatures and reactive atmospheres. We demonstrate here that operando environmental transmission...
Multiple-step nucleation pathways have been observed during mineral formation in both inorganic and biomineral systems. These pathways can involve precursor aqueous species, amorphous intermediates, or metastable phases. Despite the widespread occurrence of these processes, elucidating the precise nucleation steps and the transformation mechanisms...
In situ transmission electron microscopy (TEM) studies of dynamic events produce large quantities of data especially under the form of images. In the important case of heterogeneous catalysis, environmental TEM (ETEM) under gas and temperature allows to follow a large population of supported nanoparticles (NPs) evolving under reactive conditions. I...
Using a prototypical family of hierarchical zeolites, we show how adsorption-based characterization can be extended to provide morphological and topological assessment beyond state-of-the-art tools. The well-controlled materials under study consist...
This work was focused on the characterization of plasmonic thin films composed of Au–Ag nanoparticles dispersed in a TiO2 dielectric matrix in comparison with the monometallic Au/TiO2 plasmonic system. The thin films were prepared by reactive DC magnetron sputtering, followed by thermal annealing at different temperatures to promote nanoparticles'...
Drifts in the three directions (X, Y, Z) during the FIB-SEM slice-and-view tomography is an important issue in 3D-FIB experiments which may induce significant inaccuracies in the subsequent volume reconstruction and further quantification of morphological volume parameters of the sample microstructure. Cross-correlation is frequently applied direct...
3D analysis of an arsenic-doped silicon fin sample is performed in a transmission electron microscope (TEM). High angle annular dark-field scanning TEM (STEM-HAADF) and energy-dispersive x-ray spectroscopy (STEM-EDX) modes are used simultaneously to extract 3D complementary multi-resolution information about the sample. The small pixel size and ang...
Xenon and caesium are among the most impacting fission products when studying the nuclear fuel: xenon for its role on the fuel rod thermomechanical behaviour during reactor operation and caesium in the case of atmospheric radioactive release during an accident in a nuclear power plant. This paper focuses on the comparison of caesium and xenon therm...
Hard magnetic nanocomposites are attractive materials for integration in various microsystems and for building of next-generation permanent magnets. However, exploiting their full potential requires control of their microstructure at the nanometer scale. Studying these materials in model systems synthesized by nanofabrication routes provides intere...
This study explores the dynamic properties of Pt/CeO2 catalysts to develop active catalytic converters for Diesel exhausts. It is now well established that single Pt atoms can be stabilised on ceria surface defects in oxidising conditions. However, their catalytic activity is rather poor. A reducing treatment is required to build more active Pt nan...
A glass that won't break
Oxide glasses are important for applications ranging from smartphone screens to window panes. One familiar feature of glass is that it fractures and shatters when rapidly deformed, limiting the number of potential uses. However, Frankberg et al. found that they could deform thin films of glassy alumina (Al 2 O 3 ) with high...
Silver metal nanoparticles are among the most widely studied nanoparticles. They are widely used heterogeneous catalysts used for many purposes such as antisepsis, hydrogenation and carboxylation, but also for trapping xenon in nuclear test and detection facilities. The catalytic activity and adsorption capacity of silver nanoparticles, which depen...
The quality of metallic nanoparticles (NPs) used in heterogeneous catalysis relies through many aspects on their small size, on the homogeneity of their spatial distribution on their supports and on their ability to resist to sintering or coalescence. It is thus very important to quantify these parameters and understand the mechanisms controlling t...
Can the environmental TEM confirm atomistic models of adsorbed molecules at surfaces of solids? - Volume 25 Supplement - Matthieu Bugnet, Ihor Pershukov, Olivier Matz, Monica Calatayud, Thierry Epicier
Investigation of the Oxidation Reaction of LiFePO4 Cathode Material using Environmental TEM - Volume 25 Supplement - Matthieu Bugnet, Thierry Epicier, Martial Duchamp, Nadir Recham, Tristan Lombard, Christian Masquelier, Arnaud Demortière
Electron Tomography (ET) is of greatest interest in studying nano- and biological materials since it gives access to 3D morphological, chemical and physical features. Even though ET techniques have been continuously improved in the last decades, they are still limited: lengthy time scales (tens of minutes) are generally needed for the tilt series a...
Plasmonic Au nanoparticles embedded into a TiO2 dielectric matrix were analyzed by combining 2D and 3D electron microscopy techniques. The preparation method was reactive magnetron sputtering, followed by thermal annealing treatments at 400 and 600 ºC. The goal was to assess the nanostructural characteristics and correlate it with their optical pro...
Gasoline soot nanoparticles (SNPs) were studied by performing in situ compression tests on individual nanoparticles inside a transmission electron microscope. After consecutive compressions, the SNPs exhibited an elasto-plastic behavior, and an increasing trend in Young's modulus and hardness values. Molecular dynamics were used to simulate compres...
Atom Probe Tomography (APT), Transmission Electron Microscopy (TEM), and 3D mechanical calculations in complex geometry and anisotropic strain fields were employed to study the role of minor elements in the precipitation process of silicon and chromium nitrides in nitrided Fe–Si and Fe–Cr alloys, respectively. In nitrided Fe–Si alloys, an original...
Visualizing and Quantifying the Cationic Mobility at {100} Surfaces of Ceria: Application to CO2 Adsorption/Desorption Phenomena in the Environmental Transmission Electron Microscope - Volume 24 Supplement - M. Bugnet, S. H. Overbury, Z. Wu, F. J. C. S. Aires, F. Meunier, T. Epicier
Very Fast Tomography in the (E)TEM to Probe Dynamics in Materials during Operando and In Situ Experiments - Volume 24 Supplement - Thierry Epicier, Hussein Banjak, Anne-Sophie Gay, Thomas Grenier, Sid Koneti, Voichita Maxim, Lucian Roiban
Correlative HAADF-STEM and EDX-STEM Tomography for the 3D Morphological and Elemental Analysis of FinFET Semiconductor Devices - Volume 24 Supplement - Julien Sorel, Martin Jacob, Toby Sanders, Adeline Grenier, Rafael Bortolin Pinheiro, Frederic Mazen, Thierry Epicier, Zineb Saghi
Elastic Properties of Cerium Oxide Nanocubes from In Situ TEM Compression Tests and DFT+U Simulations - Volume 24 Supplement - Lucile Joly-Pottuz, Thierry Epicier, Tristan Albaret, Manuel Cobian, Douglas D. Stauffer, Karine Masenelli-Varlot
Experimental Evidence for the Existence of an Iridium Sesquioxide Metastable Phase during ETEM Studies of Methane Steam Reforming on an Ir/Ce0.9Gd0.9O2-x Catalyst - Volume 24 Supplement - Thierry Epicier, Mimoun Aouine, Francisco J. Cadete Santos Aires, Laurence Massin, Patrick Gélin
The nucleation and lateral growth are more and more important steps for the thin film growth of a phase (silicide, intermetallic…) when the thin film thickness is in the range or below 10 nm. It might become crucial for contact in microelectronics that are in this range of thickness for actual devices and affect the properties of contacts in differ...
Fast tomography in Environmental Transmission Electron Microscopy (ETEM) is of a great interest for in situ experiments where it allows to observe 3D real-time evolution of nanomaterials under operating conditions. In this context, we are working on speeding up the acquisition step to a few seconds mainly with applications on nanocatalysts. In orde...
Incomplete fuel burning inside an internal combustion engine results in creation of soot in the form of nanoparticles. Some of these soot nanoparticles (SNP) get adsorbed into the lubricating oil film present on the cylinder walls, which adversely affects the tribological performance of the lubricant. In order to better understand the mechanisms un...
We present a Pt@Beta catalyst with a unique, well-controlled location of metal nanoparticles that allows more efficient use of this rare, expensive metal in catalysis. The zeolite crystal has an inner cavity, leaving a thin zeolite shell where the metal nanoparticles are encapsulated, thereby ensuring a relatively small diffusional path length and...
Pt nanoparticles in a Al<sub>2</sub>O<sub>3</sub> dielectric matrix thin films are elaborated by means of atomic layer deposition. These nanostructured thin films are integrated in vertical and planar test structures in order to assess both their in-plane and out-of-plane electrical properties. A shadow edge evaporation process is used to develop p...
Yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) with different microstructures were elaborated. The isothermal tetragonal to monoclinic transformation was investigated at 134 {\deg}C in steam by X-ray diffraction, Atomic Force Microscopy (AFM) and optical interferometry. The aging kinetics were analyzed in terms of nucleation and growth...
STEM-HAADF has been used to characterize a light alkanes mild oxidation catalysts corresponding to two different MoVTe(Nb)O M1 phases. For that purpose a semi-automatic integration routine allowing the analysis of several hundreds atomic columns with a normalization procedure has been developed to determine quantitatively the vanadium content of mi...
Due to its unique redox properties, ceria is an oxide of paramount importance for a range of applications, including automotive catalytic converters, which consist of platinum-group metal nanoparticles on ceria-containing supports. In this work, the three-dimensional architecture of a ceria-based material synthesized by the widely employed glycine-...
A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (< 500 °C) and exploited to enhance the catalytic activity of Pt/CeO2-based exhaust gas catalysts. Re-dispersion of platinum in an oxidizing atmosphere already occurred at 400 °C. A protocol with reducing pul...
A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (< 500 °C) and exploited to enhance the catalytic activity of Pt/CeO2-based exhaust gas catalysts. Re-dispersion of platinum in an oxidizing atmosphere already occurred at 400 °C. A protocol with reducing pul...
Multimetallic nano-alloys display a structure and consequently physicochemical properties evolving under reactive environment. Following and understanding this evolution is therefore crucial for future applications in gas sensing and heterogeneous catalysis. In view hereof, the structural evolution of oxidized Ag25In75 bimetallic nanoparticles unde...
The influence of vanadium additions on transformation kinetics has been investigated in a medium carbon forging steel. Using dilatometry to track transformation during continuous cooling or isothermal transformation, the impact of vanadium on both ferrite-pearlite and bainite has been quantified. Transmission electron microscopy and atom probe tomo...
Atomic scale environmental transmission electron microscopy study of the surface mobility of ceria nanocubes - Volume 23 Issue S1 - M. Bugnet, S. H. Overbury, Z. Wu, F. J. C. S. Aires, T. Epicier
Nanoparticles in The ETEM: From Gas-Surface Interactions of Single Objects to Collective Behavior of Nanocatalysts - Volume 23 Issue S1 - Thierry Epicier
Oral communication at symposium Q: Nano-engineering coatings and thin films (organizers: José Filipe VAZ, Martin FENKER, Philippe STEYER, Tomas POLCAR
Controlling plasmonic systems with nanometre resolution in transparent films and their colors over large non-planar areas is a key issue for spreading their use in various industrial fields. Using light to direct self-organization mechanisms provides high-speed and flexible processes to meet this challenge. Here, we describe a route for the laser-i...
Electron tomography in transmission electron microscopy provides valuable three-dimensional structural, morphological and chemical information of condensed matter at nanoscale. Current image acquisitions require at least tens of minutes, which prohibits the analysis of nano-objects evolving rapidly such as under dynamic environmental conditions. Re...
The main goal of this research is the localization of Yb3+ and Er3+ rare earth ions and Co2+ transition metal ion as dopants in a glass ceramics composed of MgAl2O4 spinel nano-crystals of 10–20 nm size embedded in SiO2 glass. This is the first step of a compact self-Q-switched microchip laser. We conjugate, that is rather rare, both TEM-EDX and op...
Measuring with a high accuracy the size distribution of small metallic nanoparticles loaded in a mesoporous metal oxide matrix is of particular interest for many studies related to new generations of interesting metamaterials. Transmission electron microscopy (TEM) is a powerful tool to determine the nature and morphology of very small particles, b...
It is known that Fischer‐Tropsch synthesis [1] is one of the best processes to convert syngas emitted from combusted of fossil fuels like coal and natural gas into liquid gas/ liquid fuels and other petro chemicals. Moreover, iron based catalysts are known to be efficient and active components of Fischer‐Tropsch catalyst. Encapsulating iron nanopar...
The development of environmental transmission electron microscopes (ETEM) as well as the environmental cells opens the way towards operando electron microscopy. In this respect, following the genesis of a catalyst or a chemical reaction in real time under gaseous environment and at high temperature becomes a possibly achievable goal. Performing suc...
Self‐organization of metallic nanoparticles (NPs) has recently been reported upon visible continuous‐wave (cw) laser exposure [1]. The self‐organized structures are Ag NP gratings embedded in a thin TiO 2 film deposited on glass. Such composite structures exhibit singular visual effects that can find applications in secured traceability. The relate...
Modern environmental Transmission Electron Microscopes (ETEM) enables chemical reactions to be directly observed with new perspectives in the operando characterization of nano‐materials. However, morphological features are essentially missing in 2‐dimensional observations, thus nano‐tomography under environmental conditions is a new promising chall...
Sustainable chemistry, reduction of pollution, greenhouse gases control, oil refinery, liquid and solid waste management, are essential societal topics related to what is called Environmental catalysis [1], a sector which is booming rapidly for the past 10 years. So, developing innovative catalysts is a very important aspect ahead of us. To develop...
Degenerate metal oxide nanocrystals (NCs) are promising systems to expand the significant achievements of plasmonics into the infrared (IR) range1. We report on the tunable mid IR Plasmon induced in degenerate Al and Ga doped ZnO (AZO and GZO) nanocrystals. The NCs were obtained by Low Energy Cluster Beam Deposition (LECBD). By varying the Al and G...
Thin films synthesized by Physical Vapor Deposition (PVD) are currently studied to be used in different types of sensors [1,2]. Among these, sensors and electrodes used for biomedical devices are particularly important since they allow converting one or more measured signals of any living tissue into other quantities, usually an electrical signal....
Cu(In,Ga)Se 2 –based (CIGS) solar cells are thin film devices achieving nowadays the highest conversion efficiency (22.3% at the laboratory scale [1]), surpassing any other thin‐film or multi‐crystalline silicon technology. A heterojunction is obtained in these solar cells by depositing a cadmium sulfide (CdS) buffer layer (n‐type semiconductor) on...
Characterization of nanomaterials or materials at the nanoscale has drastically increased during the last decades. This increase can be explained by (i) the necessity to obtain materials with nanometer‐size grains, for instance nanocomposites, and by (ii) the use of nanoparticles in different fields, for instance lubrication applications. A challen...
The kinetic behavior of a Fe–24 Ni–0.4 C (weight percent) martensitic steel during aging at room temperature has been investigated by transmission electron microscopy. Electron diffraction, coupled with imaging techniques in a transmission electron microscope, including high resolution studies, have been used at various stages during the aging proc...
Gasification of carbon can be achieved, in the presence of metal catalysts supported on solid carbon materials, at high temperature in oxidative environments. Indeed, oxygen adsorbs and dissociates on the metal surface then interacts with the carbon at the interface with the metal leading to the formation of carbon dioxide; concurrently carbon is c...
A knowledge‐based design of catalysts requires the determination of so‐called structure‐activity‐relationships. Such correlations between the catalytic activity and its properties on the microscopic and macroscopic scales help to identify new routes for improving state‐of‐the‐art and to develop new generations of catalytic systems. However, in part...
Surface termination of solids varies according to the environment to which they are submitted. This is very important in catalysis since surface modifications have a strong influence in the way thatadsorption at the surface followed by eventual dissociation, diffusion and recombination of the molecular occur. Gaining information at atomic level on...
Bulk nanoporous silicon prepared by top-down method form Li-ion batteries was investigated combining different conventional technique such as nitrogen physisorption and high resolution electron microscopy with electron tomography. It was found that the Si nanorods are forming porous aggregates with a half of the volume of the particle occupied by p...
div class="title">Rapid Tomography in Environmental TEM: How Fast Can We Go to Follow the 3D Evolution of Nanomaterials in situ?
- Volume 22 Issue S5 - Lucian Roiban, Sid Koneti, Khan Tran, Yue-Meng Feng, Thomas Grenier, Voichita Maxim, Thierry Epicier
div class="title">Size and Environment Effect on the Room Temperature Plastic Deformation of Ceramic Nanoparticles
- Volume 22 Issue S5 - I. Issa, L. Joly-Pottuz, J. Amodéo, J. Réthoré, D. J. Dunstan, T. Epicier, I. Jenei, D. Stauffer, C. Esnouf, V. Garnier, K. Masenelli-Varlot
Calcination of Pd Nanoparticles on Delta Alumina : Ex-situ Analysis versus In-situ Environmental TEM - Volume 22 Issue S5 - Siddardha Koneti, Lucian Roiban, Anne-Sophie Gay, Priscilla Avenier, Florent Dalmas, Thierry Epicier
In situ environmental STEM-(HA)ADF has been used to characterize a light alkanes mild oxidation catalyst corresponding to a MoVTeO M1 phase. The results obtained show that there is almost no structure disordering under reaction conditions closed to ethane oxidative dehydrogenation catalytic reaction i.e. 350°C under 1 mbar of 30/15/55= O2/C2H6/N2 g...
This paper describes a fast and one-step technique to grow single gold filaments at the apex of commercial conductive AFM tips. It is implemented with an atomic force microscope in air with a high relative humidity at room temperature and is based on a bias-assisted electro-reduction of gold ions directly at the tip apex. The technique requires onl...
MICROSCOPIE+ATARI:CARE+ASR:MAO:FCA:PVE
MICROSCOPIE+ATARI:ECI2D:ING+FCA:MAO:SLO:ATU
MICROSCOPIE+ATARI:ING+FCA:MAO:CDA:FRM:DFA
The first stages of NiSi phase formation at the expense of θ-Ni2Si and a Si substrate are investigated by transmission electron microscopy (TEM). These measurements show the presence of a low density of NiSi particles at the θ-Ni2Si/Si(1 0 0) interface and allow their complete shape to be determined. This stage corresponds to the lateral growth of...
We show our approach in the structural and spectroscopic analysis of Yb3+-doped YAG nano-ceramics prepared by the low temperature-high pressure sintering technique (LTHP) by conjugation of both TEM-EDX and optical techniques. Pressure sintering dependences of absorption, emission and decays are analyzed and interpreted. The sample pressurized at 8G...
National @ CARE+ASR:MAO:FCA:PVE
Mesoporous thin films of TiO2 doped with silver can undergo spectacular microstructural modifications upon laser scanning at visible wavelengths through the excitation of a localized surface plasmon resonance in Ag nanoparticles (NPs). The latter can result in competitive physicochemical mechanisms leading either to the shrinkage or to the growth o...
The direct nucleation and growth of ferrite and cementite has been investigated in an Fe–C metallic glass using X-ray diffraction, transmission electron microscopy and atom probe tomography. The nucleation and growth proceeds via primary crystallization of ferrite, without the formation of austenite. There is no carbon gradient at ferrite/amorphous...
