Printing, Recycling and Scaling Transistors with Nanomaterial Inks

Additive printing of electronics directly onto any surface has been sought for decades. Despite significant progress, reports on fully direct-write printed electronics continue to rely on excessive thermal treatments and/or fabrication processes external from the printer. What’s more, the dimensional scalability of these printed devices remains limited to the micron regime and typically >10s microns for fully printed transistors. In this talk, recent progress towards recyclable and scalable print-in-place electronics will be discussed; print-in-place involves loading a substrate into a printer, printing all needed layers, then removing the substrate with electronic devices immediately ready to test. Inks from various nanomaterials make this possible, including semiconducting carbon nanotubes (CNTs), conducting graphene, and insulating crystalline nanocellulose. Using an aerosol jet printer, these nanomaterial-based inks are printed into thin-film transistors (TFTs) using a maximum process temperature of 70 C. Complete recyclability of these print-in-place transistors has been achieved, demonstrating the environmental sustainability of this additive manufacturing approach. The same set of carbon-based inks is shown for use in all-aqueous (completely water-based) printed CNT-TFTs, eliminating dependence on processing with hazardous chemicals. Finally, the use of a capillary flow printer will be shown to enable the direct-write printing of submicron transistors having performance competitive with commercial TFT technologies that rely on cleanroom-based fabrication.