Highly concentrated colloidal suspensions of nanocarbon (NC) materials are of great interest for a variety of applications ranging from flexible electronics and flexible conducting fibers to electrochemical catalysts for energy harvesting or storage devices. Prior to this, it is very contingent to fabricate the highly conductive and chemically compatible pastes. However, until now, NC pastes were fabricated by conventional severe oxidation process and stabilization techniques with organic dispersant, which are not optimal for high performance NC pastes. Dispersant-free fabrication of highly conductive and chemically compatible NC pastes has never been tried and still a big challenge for scientist and engineer.
Here, we report a new method for fabricating printable, spinnable, and chemically compatible conducting pastes containing high quality carbon nanotubes (CNTs) and graphene nanoplatelets in organic solvents without the need for additional dispersion agents. Our approach is based on the self-assembly of donor-donor-acceptor-acceptor arrays of hydrogen bonding sites introduced onto the NC materials. We found that the printed CNT/graphene hybrid coating showed a high electrical conductivity (>20,000 S m) that could be dramatically improved to ~500,000 S m by hybridization with a small amount of silver nanowires. Importantly, the defect formation within the NC materials was minimized even after attachment of the quadruple hydrogen bonding motifs, which contributes to the high electrical conductivity of the CNT/graphene film. In addition, we found that screen-printed NC pastes could be used as high performance electrochemical electrodes in dye-sensitized solar cells and electrochemical capacitors.