A scientist at Detroit’s Wayne State University was granted $450,000 over the course of three years from the U.S. Air Force Office of Scientific Research to study how sunlight can be used as a source of fuel.
“You have to put aircraft into the air, and that takes a tremendous amount of energy,” says Aaron Rury, the assistant professor in WSU’s Department of Chemistry who was granted the funding. “For the most part, all of that energy comes from fossil fuels. And while there’s an abundance of fossil fuels in the United States, it’s not an infinite amount.”
The history of photovoltaic devices such as solar cells dates back to 1876, when British researcher William Grylls Adams discovered that when selenium is exposed to light, it produces electricity.
“We all know about solar cells today, but we don’t think about the 50 years or more of fundamental scientific research that went into the silicon production — understanding the properties of silicon — so that you could actually formulate it into the crystalline structure and scale you need to make a solar panel,” Rury says. “What we are doing is extremely fundamental scientific research. We are studying something at a very basic level, and we have no idea where it will go.”
In September 2018, Rury and 30 other scientists and engineers from 24 research institutions and businesses received the awards after each submitted winning proposals to the Air Force’s Young Investigator Research Program. Rury’s project on Coherent Vibrational Spectroscopy of Charge Transfer Cavity Polaritons focuses on moving away from what he calls traditional synthetic methods to form the chemical fuels used every day.
“We’re forming new states of energy called polaritons,” he says. “A polariton is the sharing of energy between light particles — which are called photons — and the electrons of a molecule.”
Rury is studying how forming these polaritons changes the structure of the molecule, which is key to controlling its ability to make fuels through photochemistry. Rury compares it to photosynthesis, in which plants and bacteria create a chemical fuel for themselves from sunlight and other molecules such as water and carbon dioxide.
“To break this down, the basic premise of chemistry is to form molecules that have a particular function,” he says. “The way they’re connected in space is what dictates what kinds of properties the molecule has. Can it absorb sunlight? Can it then take that sunlight and turn it into a charged particle that can be used to do more chemistry? Those are the fundamental properties of molecules that plants use to make energy, and it’s the basis for all of life on earth.”
Plants’ photosynthesis is dependent on the structure of molecular subunits in their leaves. Rury is working to control molecular structure to find one that enables efficient fuel production through light.
The Air Force’s Young Investigator Research Award is designed to foster basic research in science and engineering to enhance early career development of young investigators, as well as increase opportunities for young investigators to recognize the Air Force mission and the related challenges in science and engineering. Rury is using the award to train graduate and undergraduate students.