A5091591123- Carbon Nanotubes in Composites
- Graphene research and applications
- Diamond and Carbon-based Materials Research
- Mechanical and Optical Resonators
- Ion-surface interactions and analysis
- 2D Materials and Applications
- Nanopore and Nanochannel Transport Studies
- Molecular Junctions and Nanostructures
- Advanced Sensor and Energy Harvesting Materials
- Quantum Dots Synthesis And Properties
- MXene and MAX Phase Materials
- Nanotechnology research and applications
- Advanced Cellulose Research Studies
- Electrospun Nanofibers in Biomedical Applications
- Nanocomposite Films for Food Packaging
- Organic Electronics and Photovoltaics
- ZnO doping and properties
- Conducting polymers and applications
- Gas Sensing Nanomaterials and Sensors
- Fullerene Chemistry and Applications
- Smart Materials for Construction
- Semiconductor materials and interfaces
- Organic Light-Emitting Diodes Research
- biodegradable polymer synthesis and properties
- Chemical and Physical Properties of Materials
Universidade Federal de Juiz de Fora
2012-2024
Instituto Nacional de Metrologia, Qualidade e Tecnologia
2009-2019
Universidade Estadual Paulista (Unesp)
2017
Universidade Federal de Minas Gerais
2006-2011
Oak Ridge National Laboratory
2009
Institute for Scientific and Technological Research
2009
Hospital das Clínicas da Universidade Federal de Minas Gerais
2005
Resonance Raman scattering is used to determine the radial breathing mode (RBM) frequency $({\ensuremath{\omega}}_{\text{RBM}})$ dependence on tube diameter $({d}_{t})$ for single-wall carbon nanotubes (SWNTs). We establish experimentally ${\ensuremath{\omega}}_{\text{RBM}}=227.0/{d}_{t}$ as fundamental relation pristine SWNTs. All other RBM values found in literature can be explained by an upshift due mostly van der Waals interaction between SWNTs and environment.
Substitutional phosphorus doping in single-wall carbon nanotubes (SWNTs) is investigated by density functional theory and resonance Raman spectroscopy. Electronic structure calculations predict charge localization on the atom, generating nondispersive valence conduction bands close to Fermi level. Besides confirming sustitutional doping, accurate analysis of electron phonon renormalization effects double-resonance process elucidates different nature donor (localized) when compared nitrogen...
Here we report the synthesis of single-walled carbon nanotube bundles by chemical vapor deposition in presence electron donor elements (N, P, and Si). In order to introduce each dopant into graphitic lattice, different precursors containing doping (benzylamine, pyrazine, triphenylphosphine, methoxytrimethylsilane) were added at various concentrations ethanol/ferrocene solutions. The synthesized nanotubes byproduct characterized microscopy Raman spectroscopy. Our results reveal intrinsic...
Bamboo, like wood, is a promising natural template for biobased devices that takes advantage of its hierarchical architecture, microarray channels, anisotropic mechanical and electrical properties. Herein we report low heat thermal treatment (HTT, 700-1000 °C) bamboo specimens to obtain bamboo-based graphitic with thermoelectric electrochemical The preservation the highly architecture three-dimensional carbon material (3D-CM) allowed adding specific properties depending on HTT pristine...
In this work, we clarify the features of lateral damage line defects in single layer graphene. The were produced through well-controlled etching graphene using a Ga+ focused ion beam. length was obtained from both integrated intensity disorder induced Raman D band and minimum fluence. Also, characterized by polarized spectroscopy. It found that is resilient under conditions since defect peak exhibits dependence on direction lines relative to crystalline lattice also laser polarization lines....
We use the Coronene (C24H12), a simple and finite molecule, to make model study spectroscopic structural alterations generated by oxygenated groups in graphene oxide (GO). Based on Lerf–Klinowski model, we chose hydroxyl [OH−], carboxyl [COOH−] epoxy [the ring C2O inside molecule] as our radicals of interest their collective isolated effects. perform geometry optimization, vibrational IR (via AM1 DFT-B3LYP) Raman spectra series functionalized coronene molecules. As results, obtain some...
Abstract Aluminum-doped zinc oxide thin films, known by the acronym AZO, were grown radio-frequency magnetron sputtering method (rf-magnetron sputtering) onto glass substrate at room temperature and without posterior heat treatment. The impact on structural, electrical, optical properties of AZO films was studied as a function following deposition parameters: working pressure, rf-power thickness. Our showed low electrical resistivity high transmittance in visible region comparable to...
The investigation of defects in transition-metal dichalcogenides (TMDs) are capital interest for future applications because they strongly change the optical, electronic, or vibrational properties such materials. In this sense, spectroscopic techniques, as Raman and photoluminescence, powerful tools to investigate optoelectronic crystal two-dimensional TMDs. work, we observed that defect-activated modes bound exciton emissions can be correlated. Specifically, investigated impact sulfur...
Abstract In this work we discuss the nature of extra peak that appears in low frequency side G′ band Raman spectra single wall and double carbon nanotubes. This has been reported many articles assigned as either from small diameter nanotubes or response for fulfilment resonance conditions with incident scattered light. Here show is present independently on distribution sample disappears after heat treatment. We believe lower component two‐peaks related to presence defects nanotube structure....
Abstract Substitutional doping on single‐wall an multi‐wall carbon nanotubes is possible by adding new atoms during the growing process. In this work we analyze changes in Raman spectra of SWNT samples substitutionaly doped with boron, nitrogen, and phosphorous. We find that small amounts dopants are not enough to change frequency tangential G mode, but there a doping‐dependent shift ω when P‐doped SWNTs measured at high laser power, indicating can thermal properties bundles. This result...
In this work, we investigate the influence of three novel 14-aril-14H-dibenzo[a,j]xanthene derivatives (XDs) modified with different functional groups as very promising hole-transporting materials for organic optoelectronic devices. Optical, electronic, and structural properties were analyzed by UV–vis absorption spectrum, cyclic voltammetry, powder X-ray diffraction (XRPD). We investigated these XD layers (HTL) on performance a simple stack bilayer OLED built commercial aluminum...
A new biopolymer obtained from onion pulp (Allium cepa L.) was employed to produce a sustainable substrate for flexible organic light-emitting diodes (FOLEDs). Indium tin oxide (ITO) and SiO2 thin films were deposited by rf-magnetron sputtering onto these biosubstrates obtain flexible, transparent, conductive anodes, on top of which FOLEDs produced. This biomaterial exhibits an optical transparency 63% at 550 nm. ITO optimized varying rf power during deposition the biopolymers, their...
Bacterial nanocellulose (BNC) is a natural biopolymer obtained by gram-negative bacteria means of green and inexhaustible biotechnological process using glucose as producing source. BCN hydrogels formed cellulose nanofibrils that maintain an open network structure, ideal matrix to produce new class organic-inorganic nanocomposites (OIN) for multifunctional applications. The polyoxometalates (POMs) are complex molecules with several metallic ions sharing oxide ions, forming highly symmetrical...
Arc discharge is the most practical method for synthesis of single wall carbon nanotubes (SWCNT). However, production SWCNT by this technique has low selectivity and yield, requiring further purification steps. This work a study heat treatment in an inert atmosphere followed supercritical fluid extraction. The raw arc material was first heat-treated at 1250 °C under argon. were submitted to extraction process using CO2 as solvent. A surfactant (tributylphosphate, TBP) chelating agent...
In the last decade, transition metal dichalcogenides (TMDs) have been intensively synthesized/studied thus linking their morphological aspect to physical properties, and consequently leading understanding of possible benefits defects in such materials. Nevertheless, for future applications, quantifying identifying TMDs is still a milestone reach order better employ these materials optoelectronic devices. Raman Spectroscopy has successfully employed graphene quantify punctual or line defects....
Nowadays, flexible organic electronics are under intense investigation for environmentally friendly and biocompatible applications. One of the main components electronic devices is substrate, which gives support building devices. There great interest in scientific community development biodegradable substrates manufacture these kinds devices, aiming at technological medical In this work, we produced a transparent biosubstrate based on gellan gum polymer by solvent casting method to...