In order to investigate the pH dependence of the peroxide-mediated reaction, functionalization was performed on unwrapped SWCNTs in buffer solutions of varying pH. In contrast to DNA-wrapped nanotubes, which must be kept within a specific pH range to maintain good dispersion, the functionalization of unwrapped SWCNTs can be performed over a wide range of pH values. pH 7 was found to be optimal for achieving a high degree of functionalization (Figure ), likely as a compromise between facilitating Reaction 1 and inhibiting Side Reactions SR1 and SR2. As shown in The SG65i-NO2-CCNTs prepared at pH 7 were analyzed with regards to their two-dimensional excitation/emission spectrum (Figure ). The functionalization of other chiralities of SWCNTs was observed, including the appearance of a (6,4) E11 -emission at ~1060 nm, along with E11 -emission peaks that likely correspond to (7,3)-and (7,5)-CCNTs. This confirms that the peroxide mediated diazonium reduction reaction can introduce defects in each of the dominant chiralities of SG65i SWCNTs. The functionalization of unwrapped SWCNTs can potentially serve as a scalable approach for the synthesis of CCNTs in applications where high uniformity of defect density is not essential.