Absorbance spectra were measured with a JASCO V-670 device from 400 to 1350 nm in 0.2 nm steps in a 10 mm path length polystyrol/polystyrene cuvette (SARSTEDT, Germany). 1D-NIR fluorescence spectra were obtained with a Shamrock 193i spectrometer (Andor Technology Ltd., Belfast, Northern Ireland) connected to an IX73 Microscope (Olympus, Tokyo, Japan). Excitation was performed with a gem 561 laser (Laser Quantum, Stockport, UK). 2D excitation-emission spectra were collected with a Monochromator MSH150 instrument, equipped with a LSE341 light source (LOT-Quantum Design GmbH, Darmstadt, Germany) as the excitation source in the setup described above. The concentration of SWCNTs was calculated with the equation developed by Weisman´s and Hertel´s group . It is based on the full width at half maximum (FWHM) and absorbance maximum.