Joining carbon nanotubes to enhance their properties

What is it about?

Single-walled carbon nanotube (SWCNT) membranes combine high electrical conductivity with exceptional mechanical stability and optical transparency; these membranes are promising for bolometers, thermophones, filters, etc. Here, we improve the performance of SWCNT membranes by engineering the intersections between the building blocks forming and defining the mechanical properties and conductivity of the material – nanotube bundles. For this, we propose a rapid and scalable technology for the tailorable treatment of SWCNT membranes with ethylene (C2H4) under resistive heating. The technology comprises the high-temperature Joule heating of an SWCNT membrane (700-1200 °C) combined with an exposition to ethylene flow at a pressure below 0.3 mPa, with an energy consumption as low as ca. 10 W/cm2. Using a set of methods (UV-vis-NIR and Raman spectroscopies, scanning and transmission electron microscopies, four-probe sheet resistance and ultimate tensile strength measurements) combined with molecular dynamics simulations, we observe the deposition of sp2 carbon coating that leads to increased conductivity and mechanical strength. We show the welded membranes to enhance the performance of the filters and transparent electrodes (after doping with HAuCl4), strengthening the material up to an order of magnitude (ultimate tensile strength ~ 22 MPa) and reaching one of the state-of-the-art performance values of 30 Ohm/sq at a transmittance of 90 % at 550 nm.

Featured Image

Photo by T.H. Chia on Unsplash

Photo by T.H. Chia on Unsplash

Why is it important?

The work showcases how to improve the electrical and optical performance of carbon nanotube thin films