Turning Light Into Energy, With Plant Leaves as a Guide

“It's always exciting to be a scientist,” said Michael Therien, William R. Kenan, Jr. Distinguished Professor of Chemistry. “The pace of discovery over my career has been remarkable. It's been fun to watch, and equally enjoyable to have made small contributions from my laboratory.”

But Therien’s and his research group’s contributions to Duke and the scientific community have been anything but small. For more than three decades, his lab’s investigations in solar photochemistry — the study of the chemical effects of light — have been funded continually by the United States Department of Energy. For several years, he has also received funding from the National Science Foundation to design biology-inspired structures that could lead to better, more efficient solar cells.

“This is a basic science lab,” Therien stressed. His group designs, builds and explores function in new molecular and nanoscale materials — substances so small they can only be viewed through high-powered microscopes — that harvest light energy from the sun and convert it into electrical charges.

Thanks to a long-standing collaboration with David Beratan, with whom he shares funding from the Keck Foundation, many of the studies Therien carries out have benefited from theoretical analyses and predictions made by Beratan and his students.

One of the lab's recent accomplishments involves gaining a fundamental understanding of the diverse optical and electrical functions of carbon nanotubes, microscopically small tubes made from carbon atoms. These tubes can possess high electrical conductivity, meaning that they allow electric currents to flow easily through them.

“Carbon nanotubes are a component for several classes of solar cells and, despite the fact that they have some commercial markets, there are still fundamental questions regarding how light is harvested and how light energy migrates and drives other reactions in them,” Therien said.

Therien looks to biology — specifically, photosynthesis in green plants — to understand how charged particles move when they interact with light. “One of the classic structures that converts solar energy into biological fuels is the green plant chloroplast,” he said. “There are many light-triggered reactions carried out in the leaves of green plants, and understanding how these reactions are controlled can help us build bio-inspired structures that harvest light and produce energy with great efficiency.”

Therien’s interest in light — light harvesting, light-triggered reactions in biology and how electrons move through proteins — began in graduate school, but really came into focus when he was a post-doctoral scholar.

Today, he shares his enthusiasm with all researchers in his lab, from post-docs to undergraduates. There are a number of pathways by which undergraduates start their research journeys, and Therien welcomes all who are curious to learn more about his work.

“There are students working with me who met me through my classes, and students who wandered into the lab because they saw a research description on the Duke website and wanted to chat,” he said.  

“One thing I encourage undergraduates to do is this: If you find something you love to do, explore that interest at Duke because there’s a huge range of potential research opportunities that will allow you to build upon these passions.”