Decoration Of Single-walled Carbon Nanotubes Research Articles

Charge Modulation Spectroscopy of Pristine and sp3-Functionalized Single-Walled Carbon Nanotube Networks

The controlled decoration of single-walled carbon nanotubes (SWCNTs) with luminescent sp3 defects has emerged as a powerful approach to enhance their usually low photoluminescence (PL) quantum yields and achieve tuneable emission across the near-infrared even for polymer-wrapped nanotubes [ACS Nano 2019, 13, 9259]. However, their application in optoelectronic devices requires a detailed understanding of the impact of sp3 functionalization on their electrical performance. While isolated sp3 defects on single SWCNTs increase the resistance by a few kΩ, the effect of functionalization on charge transport in networks of semiconducting SWCNTs remains unexplored. Charge modulation spectroscopy is ideally suited to probe the mobile charge carriers in SWCNT networks and has previously corroborated the notion that charge accumulation and transport in mixed SWCNT networks is highly chirality- and gate voltage-dependent. Here, we use charge-modulated PL (CMPL) spectroscopy to study the current pathways in field-effect transistors based on networks of pristine and functionalized (6,5) SWCNTs. We find that the defects are very efficiently sampled by mobile carriers and consequently, sp3-functionalized SWCNTs actively participate in the charge transport in these networks. In combination with voltage-dependent PL and electroluminescence measurements, our CMPL method provides fundamental insights into the interaction of charge carriers with sp3 defects in SWCNT thin film devices.Fig. 1: Schematic of the charge modulation PL spectroscopy setup (left) and CMPL spectra of pristine and functionalized (6,5) SWCNT network field-effect transistors (right). Figure 1

Single-Walled Carbon Nanotubes Decorated with Dendrimer-Encapsulated Platinum Nanoparticles as Catalytic Immobilization Matrix for Amperometric Sensing of Glutamate.

Herein, we report the functional decoration of single-walled carbon nanotubes (swCNTs) with Pt dendrimer-encapsulated nanoparticles (Pt DENs) (dia. (1.78 ± 0.18) nm) for the amperometric sensing of glutamate. The functional decoration of swCNTs was carried out via electrochemical grafting of Pt DENs onto swCNTs, and subsequent cross-linking of glutamate oxidase (GluOx) enzymes to the grafted Pt DENs on swCNT surfaces. The critical role of Pt DENs as catalytic immobilization matrix allowed both the immobilization of GluOx enzymes while maintaining the enzymatic activity of GluOx, and the electrocatalytic oxidation of H₂O₂ generated enzymatically in the presence of glutamate. Taking advantage of Pt DENs as catalytic immobilization matrix, the resulting swCNTs films, denoted as GluOx/Pt DEN/swCNTs, were applied as amperometric sensing platforms that display superior analytical characteristics, including sensitivity, selectivity, stability, and reproducibility, to the non-catalytic counterpart (i.e., GluOx/swCNTs), which led to the promising application of GluOx/Pt DEN/swCNTs to the practical analysis of glutamate in real samples.

Epoxidation of Carbon Nanocapsules: Decoration of Single-Walled Carbon Nanotubes Filled with Metal Halides.

Methyl(trifluoromethyl)dioxirane (TFDO) can be used for the oxyfunctionalization of SWCNTs filled with NaI and LuCl3 under mild conditions. The chosen metal halides are of interest for theranostics, both for imaging and therapy when in their radioactive form. The applied functionalization methodology does not require metal catalyst, preserves the integrity of the nanotubes during treatment, avoiding the release of the filling material. In this way, epoxidation can be considered as an efficient methodology for the functionalization of carbon nanocapsules, where the traditional harsh oxidation conditions by acids are not applicable.

DNA-assisted decoration of single-walled carbon nanotubes with gold nanoparticles for applications in surface-enhanced Raman scattering imaging of cells

Single-walled carbon nanotubes (SWNTs) are 1D nanostructures with distinct physical and chemical properties that have shown great promise for applications in many fields, including biomedicine. Since for biomedical application the water solubility is crucial and SWNTs have low solubility, various methods (including polymer and biopolymer wrapping, chemical modifications) have been developed to solubilize and disperse them in water. Due to their unique optical properties such as photoluminescence in the NIR and strong resonant Raman signatures, they can be used as nanoprobes in biomedical imaging and phototherapies. Furthermore, decoration of SWNTs with noble metal nanoparticles will induce an excellent surface-enhanced Raman scattering (SERS) effect of the nanoparticles-SWNTs composites, with applications in cell imaging. Herein, we present a new and facile strategy for the DNA-assisted decoration of SWNTs with gold nanoparticles (AuNPs) and their application in SERS imaging. By ultrasonication at room temperature of SWNTs with AuNPs functionalized with synthetic DNA, SWNT-AuNPs nanocomposites with enhanced Raman signal were obtained. Among the important advantages of the proposed method are the presence of the free DNA overhangs around the SWNT-AuNPs suitable for post-synthetic modification of nanocomposite through hybridization of complementary DNA strands containing molecules of interest attached by well-developed bio-conjugation chemistry.

Preparation and Characterization of Ternary Composite Composed by Chitosan, Porphyrin Derivative and Single-Walled Carbon Nanotubes (SWCNTs)

The functionalization of single-walled carbon nanotubes (SWCNTs) by noncovalent approach turned to be an effect strategy. Porphyrin and its derivatives are ideal materials for the decoration of SWCNTs. In this work, 5-(4-carboxypheny1)-10,15,20-triphenylporphyrin (H2CPTPP) was synthesized and covalently combined to the chitosan. The prepared chitosan/H2CPTPP composite was further conjugated with the oxidized SWCNTs to form chitosan/H2CPTPP/SWCNTs ternary composite. The results indicated that the carboxyl group of H2CPTPP was successfully introduced into the chitosan, which was confirmed by Fourier Transform infrared (FT/IR) spectroscopy, Raman shift and X-ray photoelectron spectroscopy (XPS). The solution of chitosan/ H2CPTPP/SWCNTs composite displays fluorescence quenching effect compared with that of chitosan/H2CPTPP composite at 615 nm and 654 nm upon excitation at 425nm.

Decoration of single-walled carbon nanotubes with Pt nanoparticles from an organometallic precursor

Carbon nanotubes (CNTs) are nanomaterials of high interest due to their unique structural, electrical, and mechanical properties. Carbon materials have been widely employed to support metallic nanoparticles for catalysis and electrochemical applications. In this work, we investigated the synthesis of platinum nanoparticles generated from the complex Pt2(dba)3 (tris(dibenzylideneacetone) diplatinum) and stabilized with a long alkyl chain amine, hexadecylamine (HDA) and supported on functionalized single-walled carbon nanotubes (SWCNTs). High resolution transmission electron microscopy (HRTEM) studies revealed isolated Pt nanoparticles (2–3 nm) on SWCNTs. Powder X-ray diffraction (XRD) was used to assess the structure of Pt nanoparticles dispersed on SWCNTs assigned to Pt face-centered cubic (fcc). Additionally, infrared Fourier transform spectroscopy confirmed the presence of the stabilizer at the surface of the Pt nanoparticles even after the purification step and functional groups at the surface of pre-treated SWCNTs. This synthetic method may be an alternative route to prepare small size Pt nanoparticles supported on functionalized SWCNTs.

Controlled Decoration of Single-Walled Carbon Nanotubes with Pd Nanocubes

Although there have been many reports of nanoparticle-decorated single-walled carbon nanotubes (SWCNTs), the morphology of the resulting nanoparticles has lacked consistency and control. The present work demonstrates a process for decorating SWCNTs with Pd nanoparticles that have a tendency toward a selective and distinct cubic shape. SWCNTs were synthesized from an embedded catalyst in a porous anodic alumina (PAA) template. A single galvanostatic electrodeposition created Pd nanowires that contacted the SWCNTs within the pores and Pd nanoparticles that decorated the SWCNTs above the surface of the PAA. A distinct change in potential was observed as nanoparticles nucleated on the SWCNTs. The effects of current density and deposition time on the morphology of the nanoparticles were studied. Optimal deposition parameters yielded Pd nanocubes with smooth and flat facets. The electrochemical response and resulting nanocubic deposits provide insights into the difference in electrochemistry between metallic an...

Selectable functionalization of single-walled carbon nanotubes resulting fromCHn(n=1–3)adsorption

Chemical functionalization of single-walled carbon nanotubes with different hydrocarbon radicals through collisional reaction between energetic methane molecule and single-walled carbon nanotubes in the energy range from 5 to 100 eV has been studied by using classical molecular dynamics simulations combined with ab initio calculations. We find that through controlling the incident energy of the methane molecule, chemical decoration of single-walled carbon nanotubes with different hydrocarbon radicals ${\mathrm{CH}}_{n}$ $(n=1--3)$ can be achieved. Various stable adsorption configurations and the corresponding electronic structures are studied based on ab initio calculations. It indicates that for the ${\mathrm{CH}}_{3}$ and CH radicals decorated (5,5) single-walled carbon nanotube, the density of states of the electrons is substantially modified.