Investigation of the light emission efficiency of single-wall carbon nanotubes wrapped with different surfactants

Single-wall carbon nanotubes dispersed in aqueous solutions of different surfactants are investigated by optical absorption and photoluminescence spectroscopies. The role played by the type of surfactant, surfactant concentration, and nanotube concentration on the efficiency of absorption and emission of light by the individualized nanotubes of different chiralities is discussed. By comparing the intensities of absorption and emission is possible to obtain the best nanotube and surfactant concentrations that optimize the light emission efficiency. Changes in the absorption and emission energies are observed and interpreted in terms of the variation of the environments screening on the exciton binding energies.