Investigation of optical properties of pristine and functionalized single-walled carbon nanotubes

Abstract

Single-walled carbon nanotubes have been synthesized by chemical vapor deposition technique followed by hydroxyl addent functionalization. Crystallographic, topographic and morphological analyses of pristine and functionalized single walled carbon nanotubes (SWCNTs) have been studied via powder X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscope and atomic force microscope respectively. UV-Vis absorption, Raman spectroscopy, thermogravemetric analysis, X-ray photo electron spectroscopy and Fourier transform infra-red spectroscopic studies have been carried out for confirmation of functionalization. Optical, quantitative and qualitative analysis of the pristine and functionalized SWCNTs have been completed via energy resolved and time resolved photoluminescence and energy dispersive X-ray spectroscopic studies respectively. Spectroscopic studies confirm the formation of good quality pristine and functionalized SWCNTs with hydroxyl addent. Recorded electron micrographs reveal the formation of fragmented functionalized SWCNTs with high aspect ratio whereas recorded diffraction patterns show the good crystallinity of synthesized nanostructures. Structural analyses of pristine and functionalized SWCNTs have been studied using Brunauer-Emmett-Teller surface area analysis, BarrettJoyner-Halenda pore size and volume analysis technique. Improved CVD method used in present studies is an ecofriendly method, which gives good yield of high quality SWCNTs.

Tip Functionalization of Finite Single-Walled Carbon Nanotubes and Its Impact on the Ground and Excited State Electronic Structure

“…Covalent functionalization occurs at the sidewalls and/or open ends or tips of the SWCNTs through chemical synthesis, oxidation, and acid treatments. − However, due to the large strain of sp 3 -hybridized groups introduced in to the nanotube lattice and the corresponding low chemical reactivity of sp 2 -hybridized carbons in the sidewalls, SWCNTs are more susceptible of being functionalized on the tips or edges . Unfortunately, a precise control over positions and concentrations of functional groups at the nanotube surface is a challenge. , A great deal of information on position and bonding modes of functional groups at SWCNTs can be obtained from experimental methods including transmission electron microscopy (TEM) , and tunneling spectroscopy (STS) , as well as infrared and Raman spectroscopy , and UV–vis absorption and emission. , However, these methods typically do not provide enough resolution needed for precise understanding of mechanisms of adsorptions of functional groups on SWCNTs.…”

Microwave assisted synthesis and characterization of graphene nanoplatelets

“…The oscillator strength, the integrated cross section of the transition, the corresponding dipole moment and Einstein's stimulated coefficient has been calculated using well known relations. (Kumar et al 2014d, e, f)…”

“…Figure 12 show time resolved decay curves recorded for microwave synthesized GNPs. Method of Kumar et al 2014b, c was used to peel off the decay curves into three exponential components (s 1, s 2 , s 3 ). Trap-depth values 'E' had been calculated using Boltzmann equation.…”

Differentiation of Bone Mesenchymal Stem Cells Into Vascular Endothelial Cell-Like Cells Using Functionalized Single-Walled Carbon Nanotubes

“…Noteworthy is that even though SWNT structures lack hydroxyl groups, a small signal is observed at 3437 cm −1 , which can be explained by OH stretching tension induced by moisture adsorbed at the interface. After treatment with EDC, the SWNT spectra show peaks at 3429 and 1632 cm −1 , which correspond to the stretching vibrations of hydroxyl groups (-NH) and inplane bending vibrations (-NH) of EDC adsorbates, respectively ( Kumar et al, 2015 ). Hence, the presence of these peaks indicates the formation of SWNTs/EDC composite coatings on the slide surface.…”