Physicists, Chemists, and Engineers Collaborate on New Electronic Technology

Electronic devices are all around us. We depend on them daily — stop lights organize our traffic patterns, our televisions entertain us, and our computers assist us at work. For the past seven years, Suchi Guha, associate professor of physics, has been researching a different form of technology called plastic electronics that could change the face of the industry. Plastic electronics, or organic electronics, consist of conductive polymers that are carbon-based like living things, whereas traditional electronics rely on inorganic semiconductors such as silicon. The conductive polymers are lighter, more flexible and less expensive than inorganic semiconductors, which make them a desirable alternative in many applications. They also create the possibility of new applications that would be impossible if using traditional electronics.

Guha oversees four graduate and two undergraduate students who work to discover what makes a good material for the use of electronics. They test to see what characteristics the materials possess, how they emit light, and what their optimal electronic and optical properties look like. The team uses simple solution processing techniques to fabricate devices and optical techniques such as light scattering. Light scattering is a process in which a laser shines on material, and the researchers study the scattered light to learn the structure of the material, and thus helping them understand structural and electronic disorder in polymers, which dictate their emission and other device aspects. Over the past four years, the group has made progress in deciphering structure-property relationships in blue-emitting polymers at the nanoscale level using the light-scattering techniques.

“Our current research activities involve fabrication and characterization of light-emitting displays, field- effect transistors, and solar cells using organic polymers and molecules,” says Guha.
For her work, Guha has received several grants from the National Science Foundation (NSF) from the engineering and materials research division because this area of research is a collaboration with physicists, chemists, and engineers. She receives raw materials from synthetic chemists in Germany and the Indian Institute of Science. The current NSF grant is also based on a strong partnership with theoretical physicists and chemists from various parts of the world.

Although organic electronics have their benefits, they are not perfect. Organic solar cells are not ideal for solar-cell applications because of their large band gap. Typically, a band gap of less than 1.5 eV is ideal for the donor material, but this is difficult to achieve with many organic molecules and polymers.
In the next year, Guha will embark upon a research leave where she will explore hybrid electronics — the combination of plastic electronics and traditional electronics. She will begin her leave at the College of Nanoscale Science and Engineering in Albany, N.Y., where she first will fabricate the device. Then she will travel to the International Institute for Materials Science in India to put the resources to the test.

“Plastic electronics are inexpensive and flexible but are slow and unorganized,” says Guha. “Traditional electronics are expensive and bulky, but fast. In the next year, I will look for the possibilities of combining the best qualities of both.”

“I have fun working with my students,” says Guha. “The nature of our research project is that it lets me work with different disciplines, so it keeps me challenged and it keeps the field going.”

Written by Laura Lindsey
Director of Communications and Marketing
The College of Arts and Science
University of Missouri Columbia

Suchi Guha