Engineers put transistors in a spin with nanocrystal inks

The study from the University of Pennsylvania, which is published in Science, reportedly opens the door for electrical components to be built into flexible or wearable applications, as the lower-temperature process is said to be compatible with an array of materials and can be applied to larger areas.

The researchers' nanocrystal-based field effect transistors were patterned onto flexible plastic backings using spin coating but could eventually be constructed by additive manufacturing systems.

The study was lead by Cherie Kagan, the Stephen J. Angello Professor in the School of Engineering and Applied Science, and Ji-Hyuk Choi, formerly a member of her lab and now a senior researcher at the Korea Institute of Geoscience and Mineral Resources.

The researchers began by taking nanocrystals, or roughly spherical nanoscale particles, with the electrical qualities necessary for a transistor and dispersing these particles in a liquid, making nanocrystal inks.

Kagan's group developed a library of four of these inks: a conductor (silver), an insulator (aluminium oxide), a semiconductor (cadmium selenide) and a conductor combined with a dopant (a mixture of silver and indium).