Polymer blend improves solar cell efficiency by 200 percent

March 04, 2015 // By Paul Buckley
A University of Cincinnati research partnership has developed a blend of polymers which could make solar cells stronger, lighter, more flexible and less expensive when compared with the current silicon or germanium technology on the market.

The researchers are claiming a three-fold increase in the efficiency of the cell technology compared with traditional solutions.

Yan Jin, a UC doctoral student in the materials science and engineering program, Department of Biomedical, Chemical, and Environmental Engineering, presented the research results this week at the American Physical Society Meeting in San Antonio, Texas, USA.

Jin will present on how a blend of conjugated polymers resulted in structural and electronic changes that increased efficiency three-fold, by incorporating pristine graphene into the active layer of the carbon-based materials. The technique resulted in better charge transport, short-circuit current and a more than 200-percent improvement in the efficiency of the devices.

“We investigated the morphological changes underlying this effect by using small-angle neutron scattering (SANS) studies of the deuterated-P3HT/F8BT with and without graphene,” explained Jin.

The partnership with the Oak Ridge National Laboratory, U.S. Department of Energy, is exploring how to improve the performance of carbon-based synthetic polymers, with the ultimate goal of making them commercially competitive.

Unlike the silicon-or germanium-powered solar cells on the market, polymer substances are less expensive and more malleable. “It would be the sort of cell that you could roll up like a sheet, put it in your backpack and take it with you,” explained Vikram Kuppa, Jin’s advisor and a UC assistant professor of chemical engineering and materials science.

One of the main challenges involving polymer-semiconductors is that they have lower charge transport coefficients than traditional, inorganic semiconductors, which are used in the current solar technology. Although polymer cells are thinner and lighter than inorganic devices, these films also capture a smaller portion of the incoming light wavelengths and are much less efficient in converting light energy to electricity.

UC doctoral student researcher Yan Jin is photographed with her advisor, Assistant Professor Vikram Kuppa. UC Assistant Professor Vikram Kuppa and Yan Jin.

“Our approach is significant because we have now shown peak improvement of over 200 percent