Evaluation of the individualization state in single-walled carbon nanotube solutions using absorption, Raman and photoluminescence spectroscopy

We report a method for characterizing the individualization of single-walled carbon nanotubes (SWCNTs) in a solution based on absorption, Raman and photoluminescence spectroscopy. In the first van Hope transition interband (S11), we selected two distinct peaks and introduced kurtosis as a quantitative value for representing the sharpness and magnitude of the peaks. Three samples of individualized SWCNTs prepared using our condition and two published conditions were analyzed using kurtosis. In addition, we used the radial breathing mode peaks and photoluminescence map to estimate the individualization qualitatively. As the result, we found that three methods to characterize the individualization state showed consistent results with each other and could be effectively utilized for making a well-individualized sample.