Auburn chemist's NSF CAREER award advances flexible electronics research, STEM outreach

Inside Dr. Chris Grieco’s laboratory in the College of Sciences and Mathematics, short bursts of laser light are helping researchers answer a question with long-term implications: How can scientists design softer, more flexible electronic materials for the technologies of the future?

The answer may begin with conducting polymers, materials that behave like plastics but can move electrical charge.

“They are essentially conducting plastics,” said Grieco, assistant professor in Auburn University’s Department of Chemistry and Biochemistry. “If we can develop conducting polymer materials, that can open up doors in many applications.”

One year into a five-year National Science Foundation CAREER award, Grieco’s research group is working to better understand how those materials move electrical charges and ions, a fundamental step toward designing new materials for flexible electronics.

The work could help advance flexible bioelectronics, including wearable and implantable biomedical devices that interface with the human body. Many electronic devices rely on metals and semiconductors such as silicon. Those materials are powerful, but they can be rigid, difficult to conform to curved surfaces and limited in how they can be chemically tuned.

Fifth-year graduate student Abdul Rashid Umar said that distinction is especially important for technologies designed to interact with biological systems over long periods of time. Compared with more traditional implant materials, conducting polymers may offer greater flexibility and compatibility with the body.

“That is why people are now looking at polymers,” Umar said. “They can be more compatible with biological systems than traditional devices.”

The Grieco Lab is not building biomedical devices directly. Instead, the group is working on the fundamental science that could make those devices possible, using laser spectroscopy to study how charge moves through conducting polymers at the molecular level.

“One of the biggest challenges in the field right now is that we are really limited in the number of available materials for applications like these,” Grieco said. “If we can learn more about how these polymers fundamentally operate, then we can guide the design of new materials.”

The lab uses a technique called ultrafast transient absorption spectroscopy, which Grieco compares to high-speed photography. Instead of capturing images, researchers use extremely short pulses of light to capture optical signals that reveal how charges move at the molecular scale.

“If we can understand that, we can learn how to better design their chemical structure so we can make better conducting materials,” Grieco said.

The possible applications extend beyond biomedical devices. Conducting polymers can also be used in electrochromic devices, where color changes in response to electricity. Graduate student Caitlyn Clark points to technologies such as electronically tinted windows or rearview mirrors that adjust to light.

“It is not just medical devices,” Clark said. “It is also electrochromic devices.”

The NSF CAREER award has also accelerated the growth of the lab itself. In its first year, the project has supported graduate students, conference travel and several scientific publications. Grieco said the award has helped expand student training, research output and the lab’s broader educational and outreach missions.

Through COSAM Outreach programs, the lab also connects its research to students across Alabama. In the Summer Science Institute, rising high school juniors and seniors build rudimentary electrochromic displays by growing polymer films and using a battery to control color changes.

“They electropolymerize the polymer themselves,” Clark said. “They put together the circuitry, connect it to the battery and then they can control the voltage to change its color.”

The group also participates in Destination STEM, an annual COSAM Outreach event that brings close to 1000 middle school students to campus. For that program, the lab built an interactive homemade spectrometer using a webcam and a DVD fragment to show students how light can be separated and measured.

“We want to get science on their mind because it might be something they are not used to seeing in middle school,” Grieco said.

The project also reaches Auburn undergraduates through a new one-credit professional development course on careers in chemistry. Clark serves as a co-instructor for the discussion-based course, which introduces students to chemistry subdisciplines, graduate school, undergraduate research and career paths in Alabama and beyond.

“A lot of times students don’t realize that they can even do research until they get to their junior or senior year,” Clark said. “It is so much easier when you give them all these options early.”

For Grieco, the research and outreach share the same long-term aim: building new possibilities, whether that means designing better materials for emerging technologies or helping more students see themselves in science.

“We are trying to better excite students, better motivate them to pursue science-related careers and help with retention in these areas,” Grieco said. “There is a lot of missing talent in chemistry, and part of that is a lack of awareness of what a chemistry career can do for you and how chemists can help to change the world.”