Science & Engineering

Federal Grants Aim To Improve Efficiencies in Solar Energy

• By Dian Schaffhauser
• 10/27/14

Researchers around the country are experimenting with improving the energy efficiency of solar cells through a number of initiatives, and the United States Department of Energy has just announced that it's funding a number of projects that offer the promise of creating the next generation of photovoltaic technologies. The federal agency recently awarded $14 million to 10 research institutions as part of its "SunShot" program, which aims to make solar energy as cost-competitive as traditional energy sources before the end of this decade. Among the recipients are the Universities of Nebraska-Lincoln, Houston, Washington and Michigan, as well as Duke University and Stanford.

This is the third round of funding for this particular program. Projects in phase 3 will research new high-performance materials such as perovskites and new techniques for creating solar cells that have high efficiency and low manufacturing costs.

U Nebraska-Lincoln, for example, won a four-year, $1.2 million award to work on refining solar cells that use perovskite, a chemical composition that has gained attention in research labs all over the world. Perovskite exists in organic form — it was first discovered in Russia in 1839 — but has since been synthesized and now refers to a specific crystalline structure as well.

Jinsong Huang, an associate professor of mechanical and materials engineering, is manipulating standard silicon-based cells with a perovskite overlay to increase the composition's capacity for converting solar energy into usable electricity. Whereas the current industry is about 20 percent, Huang hopes to increase that to 30 percent, a 50 percent improvement.

The two materials capture different wavelengths of light; the pairing of silicon with perovskite could allow the new cell to "harvest a broader spectrum of solar energy than either material could alone," the university said in a statement. Huang also is looking to make perovskite itself more efficient through a new low-temperature fabrication process that will produce perovskite in the form of a liquid solution.

"You could use the solution like you would ink in a printer or copy machine," he noted. "Think about how quickly you can print out a newspaper. With this solution, we can hopefully use existing technology to print out solar cells in the future."

David Mitzi, a professor of mechanical engineering and materials science at Duke, has been awarded a four-year, $1.3 million award also to explore improvements in the power conversion efficiency of perovskites. The project, undertaken in collaboration with Yanfa Yan, a professor of physics at the University of Toledo, will also research how to replace "heavy metal lead" currently used in the materials with less dangerous alternatives and improve how the materials respond to moisture, air and temperatures in the field.

The SunShot initiative has funded 350 projects with the goal of bringing the cost of solar down to about $0.06 per kilowatt hour. Once that's accomplished, the agency reported in a "vision study," solar-generated power could grow from less than a 200th of the current electricity supply to roughly 14 percent by 2030 and 27 percent by 2050.