The graphene sensor developed for plants. Image: Liang Dong/Iowa State University
Crops in the near future could be hybridised with graphene technology to provide even more accurate readings for farmers and cultivators.
In a little more than a decade, the agriculture sector has been transformed by internet of things (IoT) technologies, with many of the largest farms now covered in sensors, measuring everything from soil to dairy production.
A team of researchers is looking to take this a step further with low-cost, graphene-based sensors on tape that can be attached to plants and provide new kinds of data to researchers and farmers.
The Iowa State University research team recently published a paper in Advanced Materials Technologies describing its breakthrough of fabricating intricate graphene patterns on tape. The atom-thin wonder material appears to have many future applications, from wearables to conductors, and now agritech is its latest calling.
The team began its sensor development by creating indented patterns on the surface of a polymer block, which can be done either with a moulding process or with 3D printing.
The blocks are then filled with a liquid graphene solution, with tape used to remove excess graphene. Another strip of tape was used to pull away the graphene patterns, creating a sensor on the tape.
Breeding water-efficient plants
The process can produce precise patterns as small as five-millionths of a metre wide, or just one-twentieth of the diameter of the average human hair.
Because it is manufactured using standard tape, it costs just a few cents to make.
So, in the case of a “plant tattoo sensor”, as the team calls it, the sensors would be made with graphene oxide, a material very sensitive to water vapour. The presence of water vapour changes the conductivity of the material, and this can be quantified to accurately measure the release of water vapour from a leaf.
“With a tool like this, we can begin to breed plants that are more efficient in using water,” said Patrick Schnable, who led the research. “That’s exciting. We couldn’t do this before. But, once we can measure something, we can begin to understand it.”
In addition, the technology could have a wide variety of applications, the team wrote in its paper, including sensors for biomedical diagnostics, for checking the structural integrity of buildings, for monitoring the environment, and for testing crops for diseases or pesticides.
