A5026904770- Graphene research and applications
- Carbon Nanotubes in Composites
- Mechanical and Optical Resonators
- Boron and Carbon Nanomaterials Research
- Diamond and Carbon-based Materials Research
- Plasmonic and Surface Plasmon Research
- 2D Materials and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Corrosion Behavior and Inhibition
- Molecular Junctions and Nanostructures
- Quantum Dots Synthesis And Properties
- Force Microscopy Techniques and Applications
- Concrete Corrosion and Durability
- Fiber-reinforced polymer composites
- GaN-based semiconductor devices and materials
- Strong Light-Matter Interactions
- Catalytic Processes in Materials Science
- Ionic liquids properties and applications
- Fullerene Chemistry and Applications
- Catalysis and Oxidation Reactions
- Semiconductor materials and interfaces
- Thermal Radiation and Cooling Technologies
- Chalcogenide Semiconductor Thin Films
- Acoustic Wave Resonator Technologies
- ZnO doping and properties
Universidade Federal do Ceará
2015-2025
Technische Universität Berlin
2025
Universidad Nacional de Lanús
2024
Asociación por los Derechos Civiles
2024
Universität Hamburg
2018
Massachusetts Institute of Technology
2004-2014
Tohoku University
2007-2011
Universidade Franciscana
2008
Shinshu University
2008
Pontifícia Universidade Católica do Rio Grande do Sul
2008
Transition metal dichalcogenides (TMDCs) have emerged as a new two dimensional materials field since the monolayer and few-layer limits show different properties when compared to each other their respective bulk materials. For example, in some cases material is exfoliated down monolayer, an indirect-to-direct band gap visible range observed. The number of layers $N$ ($N$ even or odd) drives changes space group symmetry that are reflected optical properties. understanding function therefore...
This review focuses on the fundamental physical properties of low-dimensional carbon nanostructures (graphene, graphene nanoribbons, and nanotubes), with an emphasis understanding utilizing unique that make this class materials ideal building blocks for future nanoscience nanotechnology development. In depth discussions structural, electronic, vibrational, transport these from both theoretical experimental standpoints provide a coherent foundational overview researchers interested in broader...
The recently developed pitch-based graphitic foams have a very high thermal conductivity to weight ratio. This property allows be used in several management applications, especially the aeronautics and aerospace industries. Raman spectroscopy studies were performed on different structural regions of foam, yelding important information properties foams, as well physical graphite. foam was found composed two intermixed structures, one with stacked planes turbostratic structure. special...
The surface microchemical environment of graphene oxide (GO) has so far been oversimplified for understanding practical purposes. amount as well the accurate identification each possible oxygenated group on GO are difficult to describe not only due complex chemical nature oxidation reactions but also several intrinsic variables related production and processing GO-based materials. However, advance toward a more realistic description environment, it is necessary distinguish fragments with...
The vibrational properties of double-walled carbon nanotubes (DWNTs) is investigated by high-pressure resonance Raman scattering up to 30 GPa in two different pressure-transmitting media (PTM): paraffin oil and NaCl. protection effect on the outer tube during compression verified .The collapse DWNTs experimentally observed for first time, showing be two-step: onset 1.56 nm diameter at ∼21 followed inner 0.86 a higher pressure ∼25 GPa. This observation supported calculations. We show that...
We propose a third-order time-dependent perturbation theory approach to describe the chemical surface-enhanced Raman spectroscopy of molecules interacting with two-dimensional (2D) surfaces such as an ideal 2D metal and graphene, which are both metallic monolayers. A detailed analysis is performed for all possible scattering processes involving electrons holes considering different time orderings electron-photon electron-phonon interactions. show that metals surface enhancement if Fermi...
The inhibitory performance of three distinct protic ionic liquids (PILs), namely, 2-hydroxyethyl ammonium formate (PIL 01), propionate 02), and pentanoate 03), was evaluated to determine their suitability as eco-friendly corrosion inhibitors for carbon steel (ASTM A36) in a 3.5 wt. % NaCl aerated neutral electrolyte solution. Standard inhibitor assessment methods, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), weight loss measurements, microscopic...
The optical excitation of close-by molecules can couple into collective states giving rise to phenomena such as ultrafast radiative decay and superradiance. Particularly intriguing are one-dimensional molecular chains that form inside nanotube templates, where the tubes align single- multifile chains. resulting excitations have strong fluorescence shifted emission/absorption energies compared monomer. We study properties α-sexithiophene boron nitride nanotubes by combining with far-...
The electron-phonon coupling in two-dimensional graphite and metallic single-wall carbon nanotubes is analyzed. highest-frequency phonon mode at the $K$ point opens a dynamical band gap that induces Kohn anomaly. Similar effects take place undergo Peierls transitions driven by modes $\ensuremath{\Gamma}$ points. nonlinear dependence of frequencies on doping level gives rise to strong anharmonic nanotubes.
We use Kelvin probe force microscopy (KPFM) and capacitance coupling (dC/dz) to study the electrical properties of graphene oxide (GO). propose using dC/dz signal high frequency dielectric constant mono- few-layer GO. Our measurements suggest that dynamic GO is on order εGO ≅ 3.0 ε0, in limit, independent number layers. The are performed at a humidity controlled environment (5% humidity). effects increasing both KPFM analyzed.
Nanoindentation of soft materials is a growing research field, demanding sophisticated models to extract accurate information from these materials. In this work we investigate the nanoindentation thin films by sharp conical indenters using Finite Elements Modeling. Based on Dimitriadis et al. [Biophys. J. 82, 2798 (2002)], propose that load-displacement (F × δ) curves for can be described F = FHertz(δ)g[χ(δ,h)], where FHertz(δ) regular Hertz model, and g[χ(δ,h)] correction function includes...
We observe distinct interlayer shear mode Raman spectra for trilayer graphene with ABA and ABC stacking order. There are two rigid-plane shear-mode phonon branches in graphene. find that trilayers exhibit pronounced response from the high-frequency branch, without any noticeable low-frequency branch. In contrast, no but significant Such complementary behaviors of modes can be explained by symmetry allotropes. The strong stacking-order dependence is not found layer-breathing modes, thus...
We evaluated the antimicrobial activity and some mechanisms used by subinhibitory inhibitory concentrations of essential oil, obtained from leaves Plectranthus amboinicus, against a standard strain Klebsiella pneumoniae 5 multiresistant clinical isolates bacteria. The minimal concentration (MIC) bactericidal (MBC), rate kill pH sensitivity oil were determined microdilution tests performed in 96-well plates. Subinhibitory tested order to check its action on K. membrane permeability, capsule...
Recent optical absorption and emission experiments showed that the lower energy transitions in carbon nanotubes are excitonic nature, as predicted by theory. These were based on symmetry aspects of free electron-hole states bound states. The present work shows, however, group theory does not predict selection rules needed to explain two photon experiments. We obtain symmetries for excitons single-wall within approach wave vector, thus providing important information interpretation...