Congratulations to Katherine Woo and Shannon Lee, graduate students in chemistry, who received NASA fellowship grants from
the NASA Iowa Space Grant Consortium (ISGC) for their research into
thermoelectric materials, which can convert a heat gradient into
Katherine Woo and Shannon Lee, both graduate students in chemistry,
synthesize solid state materials useful for thermoelectrics in the lab
group of Kirill Kovnir, an associate professor of chemistry.
“Katherine and Shannon are hard-working students who are interested
in learning new ideas and creating new compounds,” Kovnir said. “With
their dedication and creativity, it is a pleasure to have such students
in the group. They also excel in attracting younger generations into the
science of chemistry via outreach activities.”
The thermoelectric materials Woo and Lee work with operate much like
batteries. In a battery, the flow of charge across a chemical gradient
creates electricity. In a thermoelectric material, the flow of charge
across a thermal gradient creates electricity. Thermoelectrics are
especially useful for powering devices on space missions where batteries
may run out and spacecraft or extraterrestrial rover may be too far
from the sun to use solar energy. In these scenarios heat generated by
the decay of a radioactive isotope can be harnessed by thermoelectric
generators to create electricity.
The main obstacle for using thermoelectric materials, especially on
Earth where other electricity sources are prevalent, is their
efficiency. Thermoelectric materials are currently not as efficient as
other electricity sources. In addition to being efficient,
thermoelectric materials must be stable, nonhazardous and reasonably low
Woo and Lee synthesize, test and tweak materials searching for
optimal thermoelectric properties. They may synthesize a material, test
its properties, then add another element into the material or change the
crystal structure of the material and test for how the properties
“By changing the structure, you can actually affect the properties,” Lee said.
As gains in efficiency of materials are made, thermoelectrics become
more practical for more uses. One way thermoelectrics can be used with
existing technology is to pair them with current machines which produce
heat as a way to harness some of the lost heat.
“I love chemistry that has a foreseeable application,” Woo said.
“Anything that has waste heat: big machines in factories, cars, even
computers, we can take this heat and actually turn it to electricity.”
Receiving the NASA grant was inspiring to both Woo and Lee.
“It’s motivational,” Woo said. “It reaffirms that the research I do has future applications.”