Dramatic electrical conductivity improvement of carbon nanotube networks by simultaneous de-bundling and hole-doping with chlorosulfonic acid

An extremely high electrical conductivity, ∼1.7 × 106 S m−1, was obtained from the films that are made of de-bundled double-wall carbon nanotubes with chlorosulfonic acid (CSA). The influence of de-bundling four different carbon nanotubes with three different surfactants (CSA, N-methyl-2-pyrrolidone, and sodium dodecylbenzenesulfonate) on electrical conductivity and thermopower was compared and analyzed with electron micrographs and Raman spectra.