A5085250834- Carbon Nanotubes in Composites
- Graphene research and applications
- Chemical and Physical Properties of Materials
- Advancements in Battery Materials
- nanoparticles nucleation surface interactions
- Molecular Junctions and Nanostructures
- 2D Materials and Applications
- Gas Sensing Nanomaterials and Sensors
- Supercapacitor Materials and Fabrication
- Spectroscopy and Quantum Chemical Studies
- Advanced Battery Materials and Technologies
- Electrocatalysts for Energy Conversion
- Nanopore and Nanochannel Transport Studies
- Porphyrin and Phthalocyanine Chemistry
- Physics of Superconductivity and Magnetism
- Magnetism in coordination complexes
- Fullerene Chemistry and Applications
- Advanced Battery Technologies Research
- Advanced Chemical Physics Studies
- Perovskite Materials and Applications
- Fuel Cells and Related Materials
- Organic Electronics and Photovoltaics
- Mechanical and Optical Resonators
- Catalytic Processes in Materials Science
- Conducting polymers and applications
Honda (United States)
2016-2025
Massachusetts Institute of Technology
2022-2023
Pennsylvania State University
2002-2017
Honda (Japan)
2007-2015
Northwestern University
2009
University of Oklahoma
2009
Rice University
2008-2009
Park University
2001
Russian Academy of Sciences
1995-1999
Semenov Institute of Chemical Physics
1994-1996
Monolayer MoS2 is a direct-gap two-dimensional semiconductor that exhibits strong electron–hole interactions, leading to the formation of stable excitons and trions. Here we report existence efficient exciton–exciton annihilation, four-body interaction, in this material. Exciton–exciton annihilation was identified experimentally ultrafast transient absorption measurements through emergence decay channel varying quadratically with exciton density. The rate determined be (4.3 ± 1.1) × 10–2...
Nanotubes to Order To exploit carbon nanotubes fully in electronic applications, one needs be able separate or synthesize either all semiconducting metallic tubes. However, unbiased synthesis conditions produce a mixture containing two-thirds tubes and one-third Harutyunyan et al. (p. 116 ) show that altering the carrier gas temperature, combination with oxidative reductive species during process modifies catalyst particles synthesis, which leads selective growth of single-walled nanotubes....
The periodic makeup of carbon nanotubes suggests that their formation should obey the principles established for crystals. Nevertheless, this important connection remained elusive decades and no theoretical regularities in rates product type distribution have been found. Here we contend any nanotube can be viewed as having a screw dislocation along axis. Consequently, its growth rate is shown to proportional Burgers vector such therefore chiral angle tube. This corroborated by ab initio...
Nanomaterials are anticipated to be promising storage media, owing their high surface-to-mass ratio. The hydrogen capacity achieved by using graphene has reinforced this opinion and motivated investigations of the possibility use it store another important energy carrier – lithium (Li). While first-principles computations show that Li pristine graphene, limited clustering phase separation, is lower than offered intercalation in graphite, we explore feasibility modifying for better storage....
The advance of nanomaterials has opened new opportunities to develop ever more sensitive sensors owing their high surface-to-volume ratio. However, it is challenging achieve intrinsic sensitivities for ultra-low level detections due vulnerability against contaminations. Here we show that despite considerable achievements in the last decade, continuous situ cleaning carbon nanotubes with ultraviolet light during gas sensing can still dramatically enhance performance. For instance nitric oxide...
Significance The gas-sensing performance of graphene could be remarkably enhanced by incorporating dopants into its lattice based on theoretical calculations. However, to date, experimental progress boron-doped (BG) is still very scarce. Here, we achieved the controlled growth large-area, high-crystallinity BG sheets and shed light their electronic features associated with boron at atomic scale. As a proof-of-concept, it demonstrated that doping in lead much sensitivity when detecting toxic...
Abstract Mixed transition‐metals (TM) based catalysts have shown huge promise for water splitting. Conventional synthesis of nanomaterials is strongly constrained by room‐temperature equilibria and Ostwald ripening. Ultra‐fast temperature cycling enables the metastable metallic phases high entropy alloy nanoparticles, which later transform to oxide/hydroxide nanoparticles upon use in aqueous electrolytes. Herein, an situ non‐noble metal oxide (HEO) on carbon fibers rapid Joule heating...
A sulfonamide-based electrolyte can greatly improve the cycling stability of commercial LiCoO 2 cathode at high cut-off voltages in Li metal||LCO batteries by stabilizing electrode–electrolyte interfaces on both anode and cathode.
A new scalable method for purification of single-wall carbon nanotubes (SWNTs) by using microwave heating in air is developed. The microwaves couple to the residual metal catalyst, raising significantly local temperature leading both oxidation and rupturing passivation layer over catalyst particles. With this protective coating weakened or removed, a mild acid treatment then sufficient remove most sample, leaving tact. Using processing 4 M HCl reflux 6 h we were able (Ni, Y) arc-discharge...
Graphene is widely regarded as one of the most promising materials for sensor applications. Here, we demonstrate that a pristine graphene can detect gas molecules at extremely low concentrations with detection limits 158 parts-per-quadrillion (ppq) range room temperature. The unprecedented sensitivity was achieved by applying our recently developed concept continuous in situ cleaning sensing material ultraviolet light. simplicity concept, together graphene's flexibility to be used on various...
The polarized absorption spectra of crystalline pentacene are obtained for excitation normal to the ab herringbone plane by measuring transmitted light in ultrathin crystals. spectral line shapes along b and orthogonal analyzed theoretically using a Holstein-like Hamiltonian which includes both Frenkel charge transfer (CT) excitons represented multiparticle basis set. model agrees with prior estimates regarding strong CT contribution (≈45%) exciton responsible b-polarized lower Davydov...
All-solid-state batteries with metallic lithium (LiBCC ) anode and solid electrolyte (SE) are under active development. However, an unstable SE/LiBCC interface due to electrochemical mechanical instabilities hinders their operation. Herein, ultra-thin nanoporous mixed ionic electronic conductor (MIEC) interlayer (≈3.25 µm), which regulates LiBCC deposition stripping, serving as a 3D scaffold for Li0 ad-atom formation, nucleation, long-range transport of ions electrons at is demonstrated....
A series of Fe and Fe/Mo catalysts, supported on alumina, were examined for Single-Walled Nanotube (SWNT) growth by Chemical Vapor Deposition (CVD) in methane. Molybdenum (20 wt %) was found to provide a clear synergistic benefit, lowering the temperature eliminating need catalyst activation hydrogen. The dependence carbon mass yield sample quality CVD conditions is discussed. Catalyst activity both oxide reduced (metallic) form investigated under low methane flow (40 cm3/min) range 600 < T...
Formation of ripples on a supported graphene sheet involves interfacial interaction with the substrate. In this work, was grown copper foil by chemical vapor deposition from methane. On thermal quenching elevated temperatures, we observed formation in graphene, developing peculiar topographic pattern form wavy grooves and single/double rolls, roughly honeycomb cells, or their combinations. Studies pure under corresponding conditions but without presence hydrocarbon revealed appearance...
The ability to synthesize compositionally complex nanostructures rapidly is a key high-throughput functional materials discovery. In addition being time-consuming, majority of conventional synthesis processes closely follow thermodynamics equilibria, which limit the discovery new classes metastable phases such as high entropy oxides (HEO). Herein, photonic flash HEO nanoparticles at timescales milliseconds demonstrated. By leveraging abrupt heating and cooling cycles induced by...
The evolution of the iron catalyst during carbon single-walled nanotube growth is studied using calorimetry, temperature-programmed oxidation and Raman measurements. Carbon-induced solid-liquid, solid-liquid-solid phase transitions nanocatalyst synthesis were observed. We found that liquid favored for nanotubes, while solidification nearly terminates growth. No was observed below eutectic point, when in solid phase. Our results support a mechanism nanotubes on particles.
Fe nanoclusters are becoming the standard catalysts for growing single-walled carbon nanotubes via chemical vapor decomposition. Contrary to Gibbs-Thompson model, we find that reduction of catalyst size requires an increase minimum temperature necessary growth. We address this phenomenon in terms solubility C and, by using first-principles calculations, devise a simple model predict behavior phases competing stability Fe-C at low temperature. show that, as function particle size, there three...
The thermal behavior of free and alumina-supported iron-carbon nanoparticles is investigated via molecular dynamics simulations, in which the effect substrate treated with a simple Morse potential fitted to ab initio data. We observe that presence raises melting temperature medium large $Fe_{1-x}C_x$ ($x$ = 0-0.16, $N$ 80-1000, non- magic numbers) by 40-60 K; it also plays an important role defining ground state smaller Fe ($N$ 50-80). main focus our study investigation Fe-C phase diagrams...
The physical state of the catalyst and its impact on growth single-walled carbon nanotubes (SWNTs) is subject a long-standing debate. We addressed it here using in situ Raman spectroscopy to measure Fe Ni lifetimes during individual SWNTs across wide range temperatures (500-1400 °C). temperature dependence underwent sharp increase around 1100 °C due solid-to-liquid phase transition. By comparing experimental results with metal-carbon diagrams, we prove that can grow from solid liquid...
In situ observation of the carbon nanotube nucleation process accompanied by dynamic reconstruction catalyst particle morphology is considered within a thermodynamic approach. It reveals driving force for detachment sp(2)-carbon cap, so-called lift-off-a crucial event in growth. A continuum model and detailed atomistic calculations identify critical factors lift-off process: (i) surface energy, affected chemisorbed atoms at exterior catalyst, exposed to feedstock; (ii) emergence pristine,...
Growth of vertically aligned carbon nanotube (CNT) forests is highly sensitive to the nature substrate. This constraint narrows range available materials just a few oxide-based dielectrics and presents major obstacle for applications. Using suspended monolayer, we show here that graphene an excellent conductive substrate CNT forest growth. Furthermore, shown intermediate growth on key substrates, such as Cu, Pt, diamond, which had not previously been compatible with We find depends degree...
The role of additives in facilitating the growth conventional semiconducting thin films is well-established. Apparently, their presence also decisive two-dimensional transition metal dichalcogenides (TMDs), yet remains ambiguous. In this work, we show that use sodium bromide enables synthesis TMD monolayers via a surfactant-mediated mechanism, without introducing liquefaction oxide precursors. We discovered ions provided by chemically passivate edges growing molybdenum disulfide crystals,...