(98g) Impact of Chemical Dopants and Passivation Schemes on Carbon Nanotube Sheet Conductivity

Carbon nanotubes (CNTs) are being investigated as an alternative to conventional metallic conductors.  Improving the electrical performance of bulk CNT materials through the use of chemical dopants is an active area of research.  The present work focuses on doping efficacy and dopant stability under various environmental conditions.  CNT sheet material was doped with a series of compounds of varying structure, and a 3 to 8-fold increase in electrical conductivity was observed after doping with potassium tetrabromoaurate, iodine, or iodine monobromide.  The general trend for the doped samples in ambient conditions was a steady decrease in electrical conductivity over several months.  These experiments served as an initial assessment of doped CNT sheet stability for conventional conductor applications and demonstrate the necessity towards passivation schemes for this emerging technology.  Different encapsulation strategies are currently being explored to retain the conductivity of the films when doped.  The conductivity of these samples is being systematically measured while storing them under ambient conditions.  Consideration for the encapsulant type, deposition technique, and solvent effects (which may dissolve the dopants from the CNT network) will be characterized.  A summary detailing the progress to date will provide an overview of both the best methods to enhance electrical conductivity in CNT sheets as well as the suitable passivation schemes for practical operation.