Ordered assembly of sorted single-walled carbon nanotubes by drying an aqueous droplet on a meshed substrate

We report on the ordered assembly of sorted single-walled carbon nanotubes (SWCNTs) (95% semiconducting tubes) by drying aqueous droplets on meshed grids with an enhanced evaporation rate. Besides the commonly observed "coffee ring" deposit of aligned SWCNTs on the droplet contact line after water evaporation, tubes self-organized in the central area of a grid and covered up to -1/3 of the whole surface area of a grid. In addition, parallel-aligned and straightened SWCNTs were seen to span across cracks in the SWCNT-surfactant film. The evaporation-driven assembly of sorted SWCNTs has the potential to produce ordered SWCNT structures that are attractive for the fabrication of electronic devices comprising mostly semiconducting or metallic tubes.