New Materials Boost Solar Energy Efficiency

12/01/2011 |

A titanium dioxide-based solar cell is expected to boost efficiency by up to 26%. A transparent semiconductor coating for dynamic windows is also on the way.

Two twists on traditional technologies dramatically improved the efficiency of solar cells and window coatings in recent tests, paving the way for better energy generation and savings.

Engineers at the University of Minnesota created a layered design for dye-sensitized solar cells, a titanium dioxide-based cell that is less expensive than traditional silicon cells andboosts efficiency by up to 26%.

Current designs for the dye-sensitized cells are only about 10% efficient because the materials don’t easily absorb infrared light. The researchers’ new design sends light ricocheting through multiple layers of microscopic spheres, increasing its path and allowing it to convert more of the electromagnetic spectrum into electricity. This strategy can easily be integrated into current commercial solar cell designs, the researchers say.

At the DOE’s Lawrence Berkeley National Laboratory, a research team has created a semiconductor coating material for windows that can control solar heat gain while remaining transparent. The coating is based on electrochromic materials, which use electric charges to tint clear windows.

Dynamic window coatings can translate into significant energy savings for commercial buildings by offsetting up to 49% of air conditioning needs and 51% of lighting, according to studies by the National Renewable Energy Laboratory.

“Traditional electrochromic windows cannot selectively control the amount of visible and near infrared light that transmit through the film. These windows can either block both regions of light or let them in simultaneously,” says Guillermo Garcia, a graduate student researcher at Berkeley Lab’s Molecular Foundry.

“This work represents a stepping stone to the ideal smart window, which would be able to selectively choose which region of sunlight is needed to optimize the temperature inside a building.”


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