Sometimes significant innovations result just from aggregating a number of different innovations into one product. So it is with a multi-institution research effort to exploit recent developments in wireless health monitoring systems and couple them with thermoelectric and piezoelectric nanomaterials to power them.
The research is being led by the Nanosystems Engineering Research Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST) headquartered at North Carolina State University in collaboration with partner institutions Florida International University, Pennsylvania State University and the University of Virginia.
“Currently there are many devices out there that monitor health in different ways,” says Dr. Veena Misra, the center’s director and professor of electrical and computer engineering at NC State in the university press release covering the research. “What’s unique about our technologies is the fact that they are powered by the human body, so they don’t require battery charging.”
While Misra may be correct in her assertion that this combination is unique within health monitoring systems, both thermoelectric and piezoelectric nanomaterials for powering devices is an area being vigorously pursued.
In the area of thermoelectric nanomaterials, we have seen significant developments this year. One coming from Wake Forest University involved using multi-walled carbon nanotubes to fabricate a thin film that the researchers claim can convert differences in temperature into electrical energy. In that case, the researchers were targeting the powering of cell phones.
A month after the Wake Forest research was announced, an international team of researchers from the California Institute of Technology, the Chinese Academy of Science's Shanghai Institute of Ceramics, Brookhaven National Laboratory and the University of Michigan developed a liquid-like material in which selenium atoms make a crystal lattice and copper atoms flow through the crystal structure like a liquid. This unusual behavior of the copper ions around the selenium lattice resulted in very low thermal conductivity (bad at conducting heat) in what is otherwise a fairly simple semiconductor (good at conducting electricity), making it an excellent candidate as a thermoelectric material.
Piezoelectric nanomaterials have been dominated until late by the use of nanowires, and specifically the research of Professor Zhong Lin Wang, Director of the Center for Nanostructure Characterization at Georgia Tech, who has almost singlehandedly kept the somewhat obscure topic of piezoelectric qualities of zinc oxide nanowires in the news. But recently graphene has entered into the area of piezoelectric materials with research coming out of Stanford University. While the Stanford research was only conducted in modeling and simulation software, it did promise to open up the fairly new conceptual field of “straintronics”.
It is not clear from either the NC State press materials or even the video that they have produced (see below), what nanomaterials they intend to use to bring on either the thermoelectric or piezoelectric effects. It will be interesting to see which direction they go with their materials.