Chirality-dependent reactivity of individual single-walled carbon nanotubes.

Electronic characteristics of a single-walled carbon nanotube (SWCNT) strongly depend on minor variations in its atomic arrangement, specifically chirality. Therefore, precise control over nanotube chirality is highly desired for their application. Theoretically, SWCNTs with different structures have different chemical reactivities, which can be further used for their chirality selection. Here, an approach is developed to examine the relationship between the chirality of SWCNTs and their intrinsic chemical reactivity. By oxidizing individual, high-quality, suspended SWCNTs and using the nanobeam electron diffraction technique, it is shown that the reactivity of SWCNTs to O2 is intricately related to their diameters, metallicity, and chiral angles. In particular, even minor differences in chiral angles lead to big differences in their reactivity, which concords with first-principles calculations. Based on the experimental observations, a chirality-dependent reactivity sequence is constructed for SWCNTs. These findings shed light on effective chiral separation of SWCNTs for their practical application in many fields.