Background: There is significant research interest in flexible electronics for their promise in wearable electronics, flexible displays, configurable and conformable photovoltaics, antennas, sensors and flexible medical devices. Traditional wafer-based devices are heavy, prone to breaking, and confined to their as-manufactured form-factor. Traditional strategies to impart flexibility can come at the cost of decreasing mechanical strength and a high incidence of delamination. A more reliable and scalable approach to the fabrication of flexible electronics that maintain mechanical strength and toughness is needed.
Technology: Ruilong Ma and Vladimir V. Tsukruk from the School of Materials Science and Engineering at Georgia Tech developed a novel screen printing approach for generating micron-scale conductive features (microcircuits) in flexible, but strong and tough biocomposite films. Here, a metal reductant paste is patterned via screen printing on the surface of a solution-cast graphene oxide biopaper. The biopaper in contact with the reductant paste is converted into highly conductive reduced graphene oxide by a patterned electrochemical reduction process. The residual reductant paste is simply rinsed away leaving a flexible, strong, and tough biocomposite film that is patterned with highly conductive reduced features. Here, the screen printing-based approach is the first to control the application of an agent for chemically converting graphene-based materials in a way that is scalable to semi-continuous roll-to-roll processing. The inventors have successfully fabricated thins films with features of 70 µm in the critical dimension across an area of 400 cm2 and have prepared fully-functional flexible humidity and proximity sensors.
Potential Commercial Applications: The microcircuits generated from this novel process maintain the mechanical and strength and flexibility of the graphene substrate while generating conductive pathways for flexible electronics. This approach provides a low-cost and scalable solution for fabricating mechanically robust and foldable conductive features on the size of single microns for emerging applications in flexible electronics. This technology has potential in industries ranging from consumer electronics, energy generation and storage and medicine. Thin film electronics are envisioned in the arena of wearable electronic textiles, photovoltaics and antennas, and human-interfaced sensors.
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