A rather accidental discovery was recently made that honey can serve as an effective, non-toxic substitute for the manipulation of the current and voltage characteristics of graphene. Researchers at the Space and Naval Warfare Systems Center Pacific (SSC Pacific) were investigating various dielectric materials they could use to fabricate a graphene transistor; First, the team tried to utilize water as a top-gate dielectric to manipulate graphene’s electrical conductivity, but this approach was unsuccessful, so they proceeded with various compositions of sugar and deionized water, which still resulted in negligible performance. When testing honey, however, an unexpected scientific discovery was made.
The team describes how honey produces a nanometer-sized electric double layer at the interface with graphene that can be used to gate the ambipolar transport of graphene. “As a top-gate dielectric, water is much too conductive, so we moved to sugar and de-ionized water to control the ionic composition in hopes we could reduce conductivity,” the team explained. “However, sugar water didn’t work for us either because, as a gate-dielectric, there was still too much leakage current….. We decided to drop-cast honey on graphene to act as top-gate dielectric— I thought maybe the honey would mimic dielectric gels I read about in literature. To our surprise—everyone said it’s not going to work—we tried and it did”.
The team from SSC Pacific, in collaboration with the University of Hawai?i at M?noa, have been developing novel graphene devices as part of a Navy Innovative Science and Engineering (NISE)-funded effort to imbue the Navy with inexpensive, lightweight, flexible graphene-based devices that can be used as next-generation sensors and wearable devices.
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