NU 2013-089
Inventors
Mark Hersam*
Michael Geier
Pradyumna Prabhumirashi
Kanan Putambekar
Ethan Secor
Abstract
Northwestern researchers have developed a novel graphene ink that achieves stable printing features on a variety of substrates. Printed electronics provide an attractive alternative to conventional technologies by enabling manufacture of low cost, large area, flexible devices that can advance applications in health diagnostics, energy storage, electronic displays, and food security. In particular, inkjet printing fabrication is a promising manufacturing technique for rapid development and deployment of new material inks. Advantages of this technology include digital and additive patterning, reduced material waste, and compatibility with a variety of substrate properties and form-factors. Although solar cells, light-emitting diodes, and sensors have been inkjet printed, the ability to pattern low-resistance metallic electrodes with fine resolution remains an important challenge as the field evolves towards highly integrated systems. This Northwestern technology is a novel graphene-based ink. Graphene is a prominent candidate as a metallic component in printed electronics due to its high conductivity, chemical stability, and intrinsic flexibility. In particular, graphene inks provide an alternative to conventional carbon-based inks that have limited conductivity in formulations compatible with inkjet printing and large-area applications for complex device architectures. The formulation of this ink, which is based on a graphene-ethyl cellulose powder, can be carefully fine-tuned to achieve stable printing features on a variety of substrates with excellent morphology. In addition, the conductivity of printed features upon mild annealing is over two orders of magnitude better than previously reported for inkjet printed graphene. Further, low processing temperatures compatible with flexible substrates, allow high tolerance of printed graphene features to bending stresses. The ink is prepared using environmentally benign materials and conditions.
Applications
Advantages
Publication
Secor EB, Prabhumirashi PL, Puntambekar K, Geier ML, and Hersam MC (2013) Inkjet Printing of High Conductivity, Flexible Graphene Patterns. Journal of Physical Chemistry Letters. 4: 1347-1351.
IP Status
A patent application has been filed.