Extinction Coefficient of single-chirality metallic and semiconducting carbon nanotubes
Xiaomin Tu, Constantine Khripin, John Howarter, Ming Zheng
The extinction coefficients of metallic and semiconducting single-wall carbon nanotubes (SWCNT) were measured on HPLC purified single-chirality DNASWCNT. Based on absorption spectroscopy and a fluorescence dye assay, the concentration of DNA on the nanotubes was obtained. X-ray photoelectron spectroscopy (XPS) provided additional information on DNA-to-nanotube ratio. The resulting extinction coefficients of semiconducting nanotubes were found to be consistent with values reported in the literature. Single-chirality metallic armchair nanotubes were recently purified by DNA-based anion-exchange chromatography and were used to measure extinction coefficient. It was the first time extinction coefficients of metallic nanotubes were experimentally determined.