Local “repristinization” of oxidized single-walled carbon nanotubes by laser treatment

Though having passed the second decade since their discovery, carbon nanotubes (CNTs) still hold promise in different fields, and many steps forward have been done. However, one major limit is given by their lack of solubility, which still represents a challenge, given the need to properly handle the material for many applications. The most efficient strategies to solve this problem often rely on a covalent chemical modification of CNT structure, in order to prevent inter-tube interactions. However, many applications, being based on CNT peculiar electronic properties, require structural integrity, and they are therefore incompatible with such strategies. We prepared strongly oxidized single-walled carbon nanotubes, with a dramatically improved dispersibility, and we performed a subsequent localized repristinization by means of laser-induced heating of the sample, during Raman analysis, consisting in both removal of the amorphous material and healing of structural defects. Our finding highlights an effect which all researchers in the field must be aware of, when using Raman spectroscopy for characterization purposes. Moreover, this local laser effect was systematically investigated in order to gain a deeper nderstanding of the phenomenon.