In general, heat is the enemy of most technologies; engines and motors can fail when they overheat and computer components tend to fritz out when they get too hot. But for Eric Tervo, an assistant professor in electrical and computer engineering and mechanical engineering at the University of Wisconsin-Madison, all that excess heat is an opportunity.
Tervo, who joined the faculty in August 2022, specializes in developing semiconductor materials for energy conversion and thermal management. In practical terms, that means researching thermophotovoltaics, or devices that convert heat into electricity; thermoradiative cells, which convert infrared heat into electricity at night; and other technologies that harness and control heat.
For Tervo, joining UW-Madison is a homecoming. Raised in Plymouth, Wisconsin, he attended UW-Madison as an undergraduate studying mechanical engineering. He then spent two years at the Southwest Research Institute in San Antonio, Texas, researching fluid dynamics, subsea leak detection and other projects related to the oil and gas industry. “After a couple of years, I decided I wanted to do something more fundamental and impactful,” he says. “I wanted to move into other energy applications, which led me to Georgia Tech for my PhD.”
For the last three years, Tervo has worked at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, as the Nozik Postdoctoral Fellow, which has given him wide latitude to pursue his own research.
One of his major focuses is thermophotovoltaics. While photovoltaics produce electricity when bombarded by photons of light from the sun (that’s the technology behind solar panels), thermophotovoltaic semiconductors produce electricity when exposed to light emitted by nearby hot objects. These devices have many potential applications, like making electricity from waste heat produced in steel or glass making, or in industrial engines or automobiles. The technology could also complement solar and wind by storing energy for use at night. Excess renewable energy could be used to heat up a block of carbon or to melt silicon or metal, then that heat could be harvested for electricity by the thermophotovoltaic cells.
At NREL, Tervo was part of a group that improved the efficiency of thermophotovoltaic cells from 30% to 40%, making the technology commercially feasible. In fact, he is currently advising several companies hoping to bring the technology to market.
At UW-Madison, Tervo, who is both a theorist and experimentalist, will continue his work on thermophotovoltaics and also plans to push forward thermoradiative cells, which have not yet been demonstrated at the device scale.
But he also hopes to explore new avenues, including electroluminescent refrigeration, in which solid-state semiconductor devices provide cooling. He would also like to investigate ways to actively control heat transport using semiconductor materials. “We can create nanostructured materials to be used as thermal diodes and switches instead of traditional electric diodes and switches, making a material turn on and off a heat flow,” he says. “This has many applications in thermal building management and in a variety of industrial processes. Essentially, it will allow heat to be controlled the same way we control electricity.”
While he is happy to return to Madison and to be closer to his relatives, family ties aren’t the only reason Tervo returned to the Badger State. The facilities at UW-Madison, including the Nanoscale Fabrication Center, the Nanoscale Imaging and Analysis Center and metalorganic chemical vapor deposition labs, will allow him to design semiconductors, fabricate them, integrate them into devices and analyze them—all on campus. “UW-Madison has really phenomenal capabilities that are not common on other campuses,” he says. “It’s all vertically integrated, and we can perform all our research in this one place.”