Diameter selective doping of single wall carbon nanotubes

Abstract

Single wall carbon nanotubes (SWCNTs) synthesized by the recently developed HiPco® method differ from those obtained by other techniques because their diameter distribution is broader and is centered at a smaller value. Therefore, HiPco® samples contain an unusual wide selection of different nanotubes. Combining this feature with different dopant molecule sizes makes it possible to study a special, diameter selective intercalation phenomenon. Here we present a comparative resonant Raman spectroscopic study on the n-type (K) and p-type (FeCl₃) doping of a HiPco® and a laser ablation grown SWCNT sample. Diameter selectivity is observed in the former but not in the latter case. We suggest that the solvability of dopands is diameter dependent with a minimum in the range d = 0.9–1.2 nm.