10 research outputs found
Excitonic Resonances in Coherent Anti-Stokes Raman Scattering from Single Wall Carbon Nanotubes
In this work we investigate the role of exciton resonances in coherent
anti-Stokes Raman scattering (er-CARS) in single walled carbon nanotubes
(SWCNTs). We drive the nanotube system in simultaneous phonon and excitonic
resonances, where we observe a superior enhancement by orders of magnitude
exceeding non-resonant cases. We investigated the resonant effects in five
chiralities and find that the er-CARS intensity varies drastically
between different nanotube species. The experimental results are compared with
a perturbation theory model. Finally, we show that such giant resonant
non-linear signals enable rapid mapping and local heating of individualized
CNTs, suggesting easy tracking of CNTs for future nanotoxology studies and
therapeutic application in biological tissues.Comment: 17 pages, 6 figure
High resolution chemical mapping of biomimetic membranes by force volume imaging
Melbourne, VIC
NearâIntrinsic Photoâ and Electroluminescence from SingleâWalled Carbon Nanotube Thin Films on BCBâPassivated Surfaces
Their outstanding electrical and optical properties make semiconducting single-walled carbon nanotubes (SWCNTs) highly suitable for charge transport and emissive layers in near-infrared optoelectronic devices. However, the luminescence spectra of SWCNT thin films on commonly used glass and Si/SiO2 substrates are often compromised by broadening of the main excitonic emission and unwanted low-energy sidebands. Surface passivation with a commercially available, low dielectric constant, cross-linked bis-benzocyclobutene-based polymer (BCB) enhances the emission properties of SWCNTs to the same level as hexagonal boron nitride (h-BN) flakes do. The presence of BCB suppresses sideband emission, especially from the Y1 band, which is attributed to defects introduced by the interaction of the nanotube lattice with oxygen-containing terminal groups of the substrate surface. The facile and reproducible deposition of homogeneous BCB films over large areas combined with their resistance against common solvents and chemicals employed during photolithography make them compatible with standard semiconductor device fabrication. Utilizing this approach, light-emitting (6,5) SWCNT network field-effect transistors are fabricated on BCB-treated glass substrates with excellent electrical characteristics and near-intrinsic electroluminescence. Hence, passivation with BCB is proposed as a standard treatment for substrates used for spectroscopic investigations of and optoelectronic devices with SWCNTs and other low-dimensional emitters
Optical and Electrochemical Properties of Single-Walled Carbon Nanotube Arrays to Silicon (100) Surfaces
Adhesion of chemically and electrostatically bound gold nanoparticles to a self-assembled silane monolayer investigated by atomic force volume spectroscopy
Ruthenium Porphyrin Functionalized Single-Walled Carbon Nanotube Arrays-A Step Toward Light Harvesting Antenna and Multibit Information Storage
Chemically immobilised carbon nanotubes on silicon : stable surfaces for aqueous electrochemistry
Diazonium ion chemistry has been used to electrochemically graft aminophenyl layers onto p-type silicon (1 0 0) substrates. A condensation reaction was used to immobilise single-walled carbon nanotubes with high carboxylic acid functionality directly to this layer. Electrochemical monitoring of the aminophenyl groups confirmed the formation of an amide linkage between the single-walled carbon nanotubes and the aminophenyl layer. The carbon nanotube electrode showed high stability and good electrochemical performance in aqueous solution. At moderate scan rates the Ru(NH3)6+3/+2 couple exhibited quasi-reversible electron transfer kinetics with a standard heterogenous rate constant of 1.2 Ă 10â3 cm sâ1 at the covalently-linked carbon nanotube surface. The electrode thus combines the advantages of a silicon substrate for easy integration into sophisticated electrical and electronic devices, carbon nanotubes for desirable electrochemical properties, and stability in aqueous medium for future applications in environmental sensing
Inner- and outer-wall sorting of double-walled carbon nanotubes
Double-walled carbon nanotubes (DWCNTs) consist of two coaxially aligned single-walled carbon nanotubes (SWCNTs), and previous sorting methods only achieved outer-wall electronic-type selectivity. Here, a separation technique capable of sorting DWCNTs by semiconducting (S) or metallic (M) inner- and outer-wall electronic type is presented. Electronic coupling between the inner and outer wall is used to alter the surfactant coating around each of the DWCNT types, and aqueous gel permeation is used to separate them. Aqueous methods are used to remove SWCNT species from the raw material and prepare enriched DWCNT fractions. The enriched DWCNT fractions are then transferred into either chlorobenzene or toluene using the copolymer PFOâBPy to yield the four inner@outer combinations of M@M, M@S, S@M and S@S. The high purity of the resulting fractions is verified by absorption measurements, transmission electron microscopy, atomic force microscopy, resonance Raman mapping and high-density field-effect transistor devices