The circuits were inkjet printed with low-cost inks that include graphene, a two-dimensional form of carbon, and were directly printed on to fabric and shown to survive 20 cycles in a typical washing machine.
The work was conducted by researchers from the Cambridge Graphene Centre at Cambridge University and Politecnico di Milano and published in the Nature Communications. The technology is being commercialised by Cambridge Enterprise, the University's commercialisation arm.
The work was based on earlier formulation of graphene inks for printed electronics. The research team was able to develop low-boiling point inks, which were directly printed onto polyester fabric. In addition, the researchers found that smoothing the fabric with a planarization layer improved the performance of the printed devices. Hexagonal boron-nitride laid down in a similar manner was used as an insulator
Among the circuits used to test against washing and bending the researchers laid down complementary inverters a reprogrammable logic OR gate, a single transistor memory cell and p-type and n-type logic inverters using the all-printed coplanar graphene. The circuits were operated at Vdd up to about 1V and with up to about 4 percent strain and up to at least 20 wash cycles.
"Other inks for printed electronics normally require toxic solvents and are not suitable to be worn, whereas our inks are both cheap, safe and environmentally-friendly, and can be combined to create electronic circuits by simply printing different two-dimensional materials on the fabric,” said Dr Felice Torrisi of the Cambridge Graphene Centre, the paper's senior author.
The work opens up a number of commercial opportunities for smart textiles and interactive clothing that could include thermoelectric power generators, sensors, displays, antennas for application in wearable computing, medical and well-being applications and the Internet of Things.
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