These carbon nanotube films exhibit high porosity and surface area to create 3D electrical contact interfaces for electrodes, improving the performance of a range of electrical devices and processes. Electrodes, which send current through non-metal materials, are integral to a wide variety of applications including welding, grounding, medical testing, and chemical processing. The electrochemical instrument market alone will reach a value of $2.2 billion in 2019. Electrodes largely rely on planar 2D interfaces between the electrode and contact material. 3D electrical contacts between electrodes and materials could benefit numerous applications by increasing conductivity through greater surface area. While some available carbon nanotube films achieve this to a certain extent, the area increase is not significant enough due to the low porosity of the films.
Researchers at the University of Florida have developed a process to fabricate highly porous, electrically conductive, single-wall carbon nanotube (SWNT) films for use as electrodes that establish high surface area 3D contact. This type of contact improves the performance of a range of electrical devices and processes such as electrochemical hydrogen production, solar cells, and electroluminescent devices.
Electrodes with carbon nanotube electrical contacts that improve device and process performance
These fabricated carbon nanotube films feature high porosity and increased electrical contact surface area. During the fabrication process, a porous membrane filters out carbon nanotubes and sacrificial nanoparticles from a surfactant suspension. These nanotubes and nanoparticles accumulate on the surface of the membrane, forming a film. Next, the membrane undergoes washing to remove the surfactant and drying to consolidate the film. Dissolution, evaporation, oxidation, pyrolysis or etching removes the sacrificial particles from the film to increase its porosity. After transferring the film to the final substrate, a solvent dissolves the membrane, leaving only the carbon nanotube film behind. The film created from this process is highly porous because of the use and removal of the sacrificial nanoparticles. These pores create a much greater surface contact area, increasing the local field strength of the electrode while keeping the resistivity low. This improved field strength can increase electron gathering for solar cells, as well as improve local conductivity and reactivity for more-efficient electroluminescent devices and electrochemical processing respectively.