A5018921059- Advanced Chemical Physics Studies
- nanoparticles nucleation surface interactions
- Surface and Thin Film Phenomena
- Graphene research and applications
- Molecular Junctions and Nanostructures
- 2D Materials and Applications
- Catalytic Processes in Materials Science
- Machine Learning in Materials Science
- Topological Materials and Phenomena
- Theoretical and Computational Physics
- MXene and MAX Phase Materials
- Electron and X-Ray Spectroscopy Techniques
- Quantum and electron transport phenomena
- Surface Chemistry and Catalysis
- Advanced Materials Characterization Techniques
- Magnetic properties of thin films
- Boron and Carbon Nanomaterials Research
- Quantum, superfluid, helium dynamics
- Advanced Physical and Chemical Molecular Interactions
- Chalcogenide Semiconductor Thin Films
- Metal and Thin Film Mechanics
- Semiconductor materials and interfaces
- Spectroscopy and Quantum Chemical Studies
- Electrocatalysts for Energy Conversion
- Force Microscopy Techniques and Applications
University of Central Florida
2015-2024
Imam Abdulrahman Bin Faisal University
2023
CY Cergy Paris Université
2010-2020
Institut des Sciences Moléculaires d'Orsay
2020
Synchrotron soleil
2020
Service de Physique de l'État Condensé
2020
Centre National de la Recherche Scientifique
2020
CEA Paris-Saclay
2020
Université Paris-Saclay
2020
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
1985-2020
Using atomic resolved scanning tunneling microscopy, we present here the experimental evidence of a silicene sheet (graphenelike structure) epitaxially grown on close-packed silver surface [Ag(111)]. This has been achieved via direct condensation silicon flux onto single-crystal substrate in ultrahigh vacuum conditions. A highly ordered structure, arranged within honeycomb lattice, is synthesized and two sublattices occupying positions at different heights (0.02 nm) indicating possible...
Scanning tunneling microscopy (STM) and ab initio calculations based on density functional theory (DFT) were used to study the self-aligned silicon nanoribbons Ag(110) with honeycomb, graphene-like structure. The honeycombs structure top of silver substrate is clearly observed by STM, while DFT confirm that Si atoms adopt spontaneously this new
We report on the electronic properties of straight, 1.6 nm wide, silicene nanoribbons Ag(110), arranged in a one-dimensional grating with pitch 2 nm, whose high-resolution scanning tunneling microscopy images reveal honeycomb geometry. Angle-resolved photoemission shows quantum confined states character. The silicon band dispersion along direction suggests behavior analogous to Dirac cones graphene different substrates.
Promoting C–C bond cleavage of ethanol by a complete 12-electron (12e) oxidation reaction (EOR) is grand challenge for the development highly efficient direct fuel cells (DEFCs). Most state-of-the-art catalysts only implement EOR in an incomplete 4e or 2e pathway because poisoning strongly adsorbed CO, leading to poor output performance and low cell efficiency DEFCs. Herein, septenary PtPdFeCoNiSnMn high-entropy alloy (PtPd HEA) with PtPd-rich surface but super-low platinum group metals...
In this paper we report on several structures of silicene, the analog graphene for silicon, silver surfaces Ag(100), Ag(110) and Ag(111). Deposition Si produces honeycomb these surfaces. particular, present an extensive theoretical study silicene Ag(111) which recent experimental studies have been published. Different were obtained only by varying silicon coverage and/or its atomic arrangement. All studied show that is buckled, with a Si-Si nearest neighbor distance between 2.28 2.5 Å. Due...
The accurate description of interface characteristics between organic molecules and metal surfaces has long been debated in theoretical studies. A well-founded geometry adsorption energy is highly desirable for these hybrid inorganic/organic interfaces. Using first principles calculations with the inclusion five van der Waals functionals (vdW-DF family), benzene (C6H6) on seven transition studied to explore performance vdW under varying surface chemistry. Our results reveal that interactions...
A novel strategy is designed to stabilize atomic Pt catalysts in alloyed platinum cobalt nanosheets with trapped interstitial fluorine (SA-PtCoF) for zinc-air batteries.
The physisorption of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) on graphene is studied using several variants density functional theory (DFT): generalized gradient approximation with inclusion van der Waals interaction (vdW) based TS approach (Tkatchenko Scheffer 2009 Phys. Rev. Lett. 102 073005) our simplified version this (here called sTS), vdW-DF (Dion et al 2004 92 246401) vdW-DF2 (Lee 2010 B 82 081101), DFT-D2 (Grimme 2006 J. Comput. Chem. 27...
The alkaline hydrogen evolution reaction (A-HER) holds great promise for clean fuel generation but its practical utilization is severely hindered by the sluggish kinetics water dissociation in solutions.
Abstract 2D materials beyond graphene and in particular semiconductors have raised interest due to their unprecedented electronic properties, such as high carrier mobility or tunable bandgap. Blue phosphorene is an allotrope of black that resembles it presents a honeycomb structure. However, known semiconductor character the crucial point determine whether this hexagonal phase Dirac fermions graphene. Here, first compelling experimental evidence blue layer grown on Cu(111) surface presented....
Our calculated vibrational properties of Ag nanocrystals show three novel, size dependent features which have broad implications for their thermodynamic and stability. There is an enhancement in the density states at low frequencies overall shift high frequency band beyond top bulk phonons. Additionally, projected surface atoms scales linearly with frequency, frequencies. The generality these results systems bond-order--bond-length correlation, average coordination, large ratio to helps...
We present a method of performing kinetic Monte Carlo simulations that does not require an priori list diffusion processes and their associated energetics reaction rates. Rather, at any time during the simulation, for all possible (single- or multiatom) processes, within specific interaction range, are either computed accurately using saddle-point search procedure, retrieved from database in which previously encountered stored. This self-learning procedure enhances speed along with...
Abstract Phosphorene is a new 2D material composed of single or few atomic layers black phosphorus. has both an intrinsic tunable direct bandgap and high carrier mobility values, which make it suitable for large variety optical electronic devices. However, the synthesis single‐layer phosphorene major challenge. The standard procedure to obtain by exfoliation. More recently, epitaxial growth on Au(111) was investigated molecular beam epitaxy obtained structure described as blue sheet. In...
The self‐assembly of cyano‐substituted triarylamine derivatives on Au(111) is studied with scanning tunneling microscopy and density functional theory calculations. Two different phases, each stabilized by at least two cyano bonding motifs are observed. In the first phase, molecule involved in dipolar coupling hydrogen bonding, while second coupling, metal‐ligand interactions present. Interestingly, metal–ligand bond already observed for deposition molecules sample kept room temperature...
In this paper, we present the first non-contact atomic force microscopy (nc-AFM) of a silicene on silver (Ag) surface, obtained by combining and scanning tunneling (STM). STM images over large areas grown Ag(111) surface show both (√13 × √13)R13.9° (4 4) superstructures. For widely observed structure, nc-AFM image is very similar to one recorded STM. The structure resolved compatible with only out two silicon atoms being visible. This indicates unambiguously strong buckling honeycomb layer.
We report results of a computational investigation, based on density functional theory, silicon self-assembled nano-ribbons (Si NRs) Ag(110). These NRs present honeycomb-like structure arched the substrate and forming closed-packed structure. The calculated STM images match experimental ones, hinting to possible new Si structure, mediated by Ag substrate. observed electronic states near Fermi level were reproduced calculations attributed confinement/hybridization tandem.
Abstract The emergence of peculiar phenomena in 1D phosphorene chains (P chains) has been proposed theoretical studies, notably the Stark and Seebeck effects, room temperature magnetism, topological phase transitions. Attempts so far to fabricate P chains, using top-down approach starting from a few layers bulk black phosphorus, have failed produce reliably precise control chains. We show that molecular beam epitaxy gives controllable bottom-up grow atomically thin, crystalline flat on...
We have examined the impact of vibrational free energy on self-diffusion Cu(100) and Ag(100) within framework transition state theory. The local thermodynamic functions are calculated from density states extracted using interaction potentials based embedded atom method. find that, as temperature rises to 600 K, contributions lead a decrease preexponential factor about 2 orders magnitude, lowering barriers by 10%, an increase in activation 20%. net effect diffusion constant is significant.
We report the results of Olympicene radical (C19H11) adsorption characteristics on Cu(111) obtained within density functional framework with and without inclusion self-consistent van der Waals (vdW) interactions to evaluate their effects. Our calculations suggest that vdW enhance energies, degree enhancement strongly depends implementation. Among considered configurations, highest energy calculated using PBE is found be 0.24 eV, while those are 1.32 eV (rPW86), 1.91 (optPBE), 2.29 (optB88),...