Low-Cost Catalyst Ink for Simple Patterning and Growth of High-Quality Single- and Double-Walled Carbon Nanotubes.

Research into carbon nanotubes (CNTs) has been a hot topic for almost 3 decades, and it is now that we are beginning to observe the impact of advanced applictions of this nanomaterial in areas such as electronics. Currently, in order to mass produce CNT devices, either large-scale synthesis, followed by numerous energy-intensive processing steps or photolithography processes, including several sputter-deposition steps, are required to pattern this material to fabricate functional devices. In the work reported here, through the utilization of a universal catalyst precursor (cyclopentadienyl iron dicarbonyl dimer) and the optimization of solution parameters, patterned high-quality vertically aligned arrays of single- and few-walled CNTs have been synthesized via various inexpensive, commercially scalable methods such as inkjet printing, stamp printing, spray painting, and even handwriting. The two-step process of precursor printing, followed immediately by CNT growth, results in CNTs with a Raman ID/IG ratio of 0.073, demonstrating very high-quality nanotubes. This process eliminates time-consuming and costly CNT post processing techniques or the deposition of numerous substrate barrier and catalyst layers to achieve device manufacturing. As a result, this method has the potential to provide a route for the large-scale synthesis of high-quality single- and few-walled CNTs that can be applied in industrial settings.