Efficient Spectrofluorimetric Analysis of Single-Walled Carbon Nanotube Samples

Abstract

A new method and instrumentation are described for rapid compositional analysis of single-walled carbon nanotube (SWCNT) samples. The customized optical system uses multiple fixed-wavelength lasers to excite NIR fluorescence from SWCNTs individualized in aqueous suspensions. The emission spectra are efficiently captured by a NIR spectrometer with InGaAs multichannel detector and then analyzed by a computer program that consults a database of SWCNT spectral parameters. The identities and relative abundances of semiconducting SWCNTs species are quickly deduced and displayed in graphs and tables. Results are found to be consistent with those based on manual interpretation of full excitation-emission scans from a conventional spectrofluorometer. The new instrument also measures absorption spectra using a broadband lamp and multichannel spectrometers, allowing samples to be automatically characterized by their emission efficiencies. The system provides rapid data acquisition and is sensitive enough to detect the fluorescence of a few picograms of SWCNTs in ~50 μL sample volumes.

Influence of cysteine doping on photoluminescence intensity from semiconducting single-walled carbon nanotubes

“…This assumption is based on the effective deprotonation of the thiol group and also supported by the fact that such thiol-containing compound as dithiothreitol (DTT) is the strong reducing agent which increases essentially the nanotube PL QY [9,11,12]. PL spectra of SWNT:ssDNA at every cysteine concentration were fitted with a sum of curves described by a function similar to the Voigt function [17]. The area of each curve was matched with the PL integral intensity of appropriate nanotube species.…”

The Effect of DNA and Sodium Cholate Dispersed Single-Walled Carbon Nanotubes on the Green Algae Chlamydomonas reinhardtii

“…Additionally, fluorescence efficiency of DNA:SWCNT was greater than that of SC:SWCNT, suggesting DNA is more effective at dispersing individual SWCNTs than SC, which was expected [12,24,26]. Fluorescence efficiency is a relative measure of dispersion with the principle being that more well-dispersed SWCNTs have greater fluorescence output for a given concentration, which is measured by absorbance [31,32]. By virtue of photoluminescence from both DNA:SWCNT and SC:SWCNT, fluorescence efficiency measurements suggest that the SWCNTs are well-dispersed in solution as expected.…”

“…This software also calculated the SWCNT diameter distribution from the absorbance and integrated fluorescence measurements. Fluorescence efficiency measurements, which are fluorescence power collected across the emission spectrum for a single excitation wavelength divided by the absorbance spectrum, are reported as a relative measure of SWCNT dispersion in solution [31,32].…”

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: A review

“…However, these authors indicated that the local environment of the CNTs and reabsorption at high concentrations affect the overall photoluminescence intensity. Recently, Rocha et al [104] described a new characterization method for SWCNTs based on a customized NIR fluorescence instrument that employed multiple fixedwavelength lasers for nanotube excitation. The emission spectra obtained were analyzed using a SWCNT spectral database and the type and relative distribution of the bulk sample were rapidly displayed.…”