A5022861879- Carbon Nanotubes in Composites
- Graphene research and applications
- Diamond and Carbon-based Materials Research
- Boron and Carbon Nanomaterials Research
- Mechanical and Optical Resonators
- Ferroelectric and Piezoelectric Materials
- Microwave Dielectric Ceramics Synthesis
- Fullerene Chemistry and Applications
- Nanoparticles: synthesis and applications
- Solid-state spectroscopy and crystallography
- Molecular Junctions and Nanostructures
- Thermal Expansion and Ionic Conductivity
- 2D Materials and Applications
- Transition Metal Oxide Nanomaterials
- Graphene and Nanomaterials Applications
- Crystal Structures and Properties
- Quantum and electron transport phenomena
- Gas Sensing Nanomaterials and Sensors
- Thermal properties of materials
- Force Microscopy Techniques and Applications
- Supercapacitor Materials and Fabrication
- Luminescence Properties of Advanced Materials
- Advancements in Battery Materials
- Gold and Silver Nanoparticles Synthesis and Applications
- Nanotechnology research and applications
Universidade Federal do Ceará
2015-2024
Pontifical Catholic University of Rio de Janeiro
2022
Universidade de Fortaleza
2020
Hospital São Rafael
2008-2018
Hospital Geral de Fortaleza
2018
Universidade Estadual de Campinas (UNICAMP)
2004-2014
Universidade Estadual do Ceará
2010
Universidade Federal do Pampa
2010
Massachusetts Institute of Technology
2001-2010
Shinshu University
2008-2010
The basic concepts and characteristics of Raman spectra from carbon nanotubes (both isolated bundled) are presented. general the radial breathing mode, tangential mode (G band), disorder-induced (D-band) other features presented, with focus directed toward their use for nanotube characterization. Polarization analysis, surface enhanced spectroscopy complementary optical techniques also discussed in terms advantages limitations.
This review discusses advances that have been made in the study of defect-induced double-resonance processes nanographite, graphene and carbon nanotubes, mostly coming from combining Raman spectroscopic experiments with microscopy studies development new theoretical models. The disorder-induced peak frequencies intensities are discussed, particular emphasis given to how features evolve increasing amounts disorder. We address here two systems, ion-bombarded where disorder is represented by...
The phonon dispersion relations of graphite can be probed over a wide range the Brillouin zone by double resonance Raman spectroscopy. process provides us with new assignments for dispersive and nondispersive features observed in spectra disordered carbon nanotubes, some having been incorrectly assigned previously, or not at all.
We report G-band resonance Raman spectra of single-wall carbon nanotubes (SWNTs) at the single-nanotube level. By measuring 62 different isolated SWNTs resonant with incident laser, and having diameters ${d}_{t}$ ranging between 0.95 nm 2.62 nm, we have conclusively determined dependence two most intense features on nanotube structure. The higher-frequency peak is not diameter dependent $({\ensuremath{\omega}}_{G}^{+}=1591 {\mathrm{cm}}^{\ensuremath{-}1}),$ while lower-frequency given by...
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 optical absorption spectra of \ensuremath{\pi} electrons are calculated for graphite and carbon nanotubes. Particular attention is paid to the processes contributing as a function electron wave vector k light polarization direction. amplitude around K point in Brillouin zone has node two-dimensional graphite. formula scattering matrix given analytically by expanding element into Taylor series. chirality dependence single-wall nanotube presented.
A review of double resonance Raman spectroscopy is presented. Non-zone centre phonon modes in solids can be observed the spectra, which weak signals appear a wide frequency region and their combination or overtone assigned. By changing excitation laser energy, we derive dispersion relations single nanotube.
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In this work we analyze the room-temperature linewidth for several Raman features (i.e., radial breathing mode, G band, D and ${G}^{\ensuremath{'}}$ band) observed individual isolated single-wall carbon nanotubes (SWNTs). Temperature-dependent measurements on SWNT bundles SWNTs show that anharmonic effects are not important broadening at room temperature. Measurements a large number of samples (170 SWNTs) allow us to filter out effect from extrinsic properties (e.g., defects, tube...
Despite the advanced stage of diamond thin-film technology, with applications ranging from superconductivity to biosensing, realization a stable and atomically thick two-dimensional material, named here as diamondene, is still forthcoming. Adding outstanding properties its bulk counterparts, diamondene predicted be ferromagnetic semiconductor spin polarized bands. Here, we provide spectroscopic evidence for formation by performing Raman spectroscopy double-layer graphene under high pressure....
In this work, a study of resonance effects in the Raman spectra twisted bilayer graphene (tBLG) is presented. The analysis takes into account effect mismatch angle $\ensuremath{\theta}$ between two layers, and also excitation laser energy on frequency, linewidth, intensity main features, namely rotationally induced $R$ band, $G$ second-order ${G}^{\ensuremath{'}}$ (or $2D$) band. are explained based dependence tBLG electronic structure, as calculated by ab initio methodologies. twist defines...
The structural and electronic properties of $\mathrm{Cr}{\mathrm{O}}_{3}$ interacting with graphene layer are calculated using ab initio methods based on the density functional theory. acts as an electron acceptor modifying original magnetic surface through adsorption process. changes induced in strongly dependent site, for some sites, it is possible to open a gap band structure. Spin polarization effects also predicted configurations which binding energy lower charge transfer higher.
This article reviews recent advances on the use of Raman spectroscopy to study and characterize carbon nanostructures. It starts with a brief survey graphene nanotubes, followed by developments in field. Various novel topics, including Stokes–anti-Stokes correlation, tip-enhanced two dimensions, phonon coherence, high-pressure shielding effects, are presented. Some consequences for other fields—quantum optics, near-field electromagnetism, archeology, materials soil sciences—are discussed....
Carbon functional materials (CFMs) such as biochar and hydrochar can be obtained from hundreds of biomass precursors varying urban sludge to agriculture wastes. They produced through tens synthesis methods postsynthesis processing steps tuned at specific conditions (e.g., temperature, time, chemical concentrations). To achieve a "rational design" platform for system with high dimensional parameter space CFMs, we processed 10,975 scientific articles (from years 2000 2020) related the subject...
In this work, we discuss all possible double resonance processes which explain the observed features of disorder-induced D band and its overtone, ${G}^{\ensuremath{'}}$-band, in Stokes (S) anti-Stokes (AS) Raman spectra two-dimensional graphite. It is shown that composed by two peaks,which are not associated with resonances incident scattered photons, but rather related to whether first scattering an electron a phonon or defect. The model explains experimental results concerning frequency...