Figure 3: Optical analysis of the separated fractions.
(a) Normalized UV-Vis-NIR spectra after pH-neutral separation of HiPco SWCNTs (blue), acidic conditions (pH 1.8, black) and the freestanding sheet (pH 2.5, red). (b) The Kataura plot was reproduced from calculations following48 shown in the diameter range of HiPco SWCNTs. E22 transitions were taken from49. Red dots indicate metallic SWCNTs, green dots show semiconducting SWCNTs. The dashed lines in (b) indicate the laser wavelengths used for Raman spectroscopy. (c,d) Normalized Raman signals of SWCNTs obtained at neutral (blue), acidic conditions (pH 1.8, black) and the freestanding sheets (pH 2.5, red) were recorded at 633 nm excitation and 514 nm, respectively. All spectra were offset into the y-direction for clarity.
