Purity Evaluation of As-Prepared Single-Walled Carbon Nanotube Soot by Use of Solution-Phase Near-IR Spectroscopy

Abstract

We report a rapid, quantitative procedure for the evaluation of the carbonaceous purity of bulk quantities of as-prepared single-walled carbon nanotube (SWNT) soot by the utilization of solution-phase near-IR spectroscopy. The procedure starts with two steps of homogenization followed by solution/dispersion spectroscopy of a representative part of the bulk sample. The purity is evaluated against a reference sample by utilizing the region of the second interband transition (S 22 ) for semiconducting SWNTs. The procedure is found to be capable of reliably analyzing the carbonaceous purity of a 10-g batch of SWNTs produced by the electric arc discharge method to within 3%.

Optimizing sonication parameters for dispersion of single-walled carbon nanotubes

“…For a given absorption spectrum of SWCNTs, it has been shown that well-resolved features mean the fraction of individual SWCNTs is higher [29]. The I MAX -to-FWHM ratio has been proven to be related to the degree of SWCNT debundling and aggregation, which is used to evaluate the purity of SWCNT samples [31][32]. As shown in Fig.…”

Targeted removal of bioavailable metal as a detoxification strategy for carbon nanotubes

“…Following the initial release of a trace amount of Ni, there is no detectable release and thus no indication of significant oxidative attack on the covering carbon shells for two months. ** Carbonaceous purity is defined in the literature as the mass ratio of pure SWCNT to the total carbonaceous material and it is evaluated by near-IR spectroscopy against a reference sample [31].…”

Centrifugal purification of chemically modified single-walled carbon nanotubes

“…Very recently, Haddon et al [29] proposed a spectroscopic approach to quantitatively evaluate the purity of SWNTs. We attempt to apply this method to estimate the purity of the shortened SWNTs.…”

“…Though a 100% pure SWNT sample is unavailable, we could estimate the purity of our functionalized full-length SWNTs with respect to the reference sample R2 in Ref. [29], which is an 'impurity-free' fragment of soot directly from the arc chamber. By referencing to the documented datum A(S 22 ,R2)/A(T,R2)Z0.141, we could conclude that the relative purity of our functionalized shortened SWNTs is 129% (0.1818/0.141).…”

“…The relative purity of SWNTs to reference R2 [29] in a dispersion is obtained by comparing the relative ratio of the aerial absorption after baseline subtraction and the total aerial absorption in the S 22 interband transition. Table 1 4-6) are of the highest purity.…”