Jinsong Huang sees a future where everyday items like clothing, laptop bags and windows are covered with inexpensive, pliable solar cells.
The National Science Foundation liked the idea so much it gave the University of Nebraska-Lincoln assistant engineering professor a $400,000 grant to continue researching solar cell development.
"People really want to convert solar energy into electricity, but it's too expensive now compared to fossil or nuclear energy,” Huang said. “So we want to make solar competitive with other types of energy."
Today's solar cells use a semiconductor, usually silicon, sandwiched between two metal electrodes that create an electric field. One electrode is transparent to allow light to pass. The photons in sunlight knock loose the semiconductor's negatively charged electrons, which migrate within the system's electric field to form a current.
That current is harnessed as electricity. Although silicon-based solar cells are efficient, they are expensive to produce and limited in their applications, Huang said.
Scientists are working to replace silicon with organic polymers, or plastics, which are cheaper and more flexible, but also less energy efficient.
Huang and his colleagues are working to improve organic polymers' efficiency as semiconductors. They discovered that placing a layer of ultrathin ferroelectric polymer between each electrode and the organic polymer increases the device's energy efficiency.
Ferroelectric polymers are inexpensive materials that hold large permanent electrical polarizations on each side. This increases a solar cell's internal electric field and, in turn, generates more electrical current.
One of the biggest challenges for polymer solar cells is to make them as efficient as silicon solar cells. That requires taking the energy conversion efficiency of polymer solar cells up to 15 or 20 percent, and Huang is about halfway to that threshold.
Used in spray paints and ink jets, organic polymers may allow solar cells to be made as quickly and easily as printing the daily newspaper, Huang said.