Towards Commercial Viability of Flexible Transparent Conductive Films: New Single Walled Carbon Nanotubes Ink

S. Fogden, C. Ma, K-C Kim, K. Ligsay, A. Catheline, A. Ostfeld, A.C. Arias, G. McFarlane
Linde, US

Keywords: single walled carbon nanotube, TCF, display, PV

Summary:

Commercial interest is growing in alternatives to Indium Tin Oxide (ITO) for transparent conductive films (TCFs) to decrease cost and increase functionality, of the emerging ITO alternatives, Single Walled Carbon Nanotubes (SWNTs) show the most promise due to their outstanding electrical, optical and mechanical properties. Commercial uptake however, has been slow because bulk quantities of material with purity levels that do not compromise optical and electrical properties are not available. In addition to purity, the length and bundle size of SWNTs have been shown to affect the conductivity scaling of SWNT films. We have investigated how nanotubide inks, produced from SWNTs reduced in liquid ammonia can impact the conductivity scaling factors. Reduced SWNTs spontaneously dissolve in aprotic organic solvents without the need for additional mechanical energy. This mild dissolution technique results in solutions of long, undamaged, individualized SWNTs. Using spin and spray coating deposition techniques these nanotubide inks can be deposited onto glass or PET substrates giving low resistivity at high transparency. At the lab scale, photovoltaic devices made using these TCFs have been successfully produced. The developments presented here, may pave the way for the mainstream use of SWNT based TCFs in both the touch and display markets.