This electrochemical transistor was made from cotton with nanoparticle-based coatings.
Credit: Cornell University
A growing trend in portable diagnostic devices allows for sensing and reporting of glucose levels, heart rate, or blood pressure, but advances made in creating transistors from cotton may lead to the creation of clothing acting as medical devices. A collaborative effort between scientists and engineers from Cornell University (Ithaca, NY), Ecole Nationale Supérieure des Mines de Saint-Étienne in France. and Italy's University of Bologna and the University of Cagliari, has resulted in an organic electrochemical transistor made from cotton fibers.
The researchers chose cotton due to its comfort, mechanical properties, widespread use, and cheapness, and they started by creating a conformal layer of nanoparticles over the rough topography of the cotton fibers. These conformal coatings included gold nanoparticles and layers of either conductive or semiconductive coatings, applied so thin that the cotton was still flexible.
After the fibers were coated, the researchers built the devices, with the gate, drain, and source all made from the coated cotton threads. Both organic electrochemical transistors and organic field transistors were demonstrated, which are both widely used components of integrated circuits.
The cotton transistor is a step toward creating more complex devices like cotton-based circuits, and eventually fabrics that could sense body temperature and heat up or cool down, or monitor blood pressure or heart rate. The research was published in Organic Electronics.