Quantifying (n,m) species in single-wall carbon nanotubes dispersions by combining Raman and optical absorption spectroscopies

Abstract

Optical absorption in combination with resonant Raman spectroscopies were used for the determination of (n,m) distribution and the absolute concentration of single-wall carbon nanotubes (SWCNT) species in few chiralities enriched dispersions. Relative (n,m) content was obtained from Raman excitation profiles of the radial breathing modes corrected by the respective Raman cross sections. Absolute concentrations were obtained from the analysis of the optical absorption spectra. The combination of Raman and optical absorption results allowed us to quantify the concentration of each individual species present in the samples and to calculate the oscillator strength for five semiconducting single-wall nanotube species. The oscillator strength is related to the diameter and chiral angle, and their values for E11 and E22 optical transitions present opposite behavior if 2n+m mod 3 = 1 or 2. The proposed protocol can be used as a reliable metrological method for measuring the concentration of SWCNT species in a sample.