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Solar cells get a boost from bouncing light

Date:
August 2, 2011
Source:
American Institute of Physics
Summary:
A new twist on an old solar cell design sends light ricocheting through layers of microscopic spheres, increasing its electricity-generating potential by 26 percent.
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A new twist on an old solar cell design sends light ricocheting through layers of microscopic spheres, increasing its electricity-generating potential by 26 percent.

By engineering alternating layers of nanometer and micrometer particles, a team of engineers from the University of Minnesota has improved the efficiency of a type of solar cell by as much as 26 percent. These cells, known as dye-sensitized solar cells (DSSC), are made of titanium dioxide (TiO2), a photosensitive material that is less expensive than the more traditional silicon solar cells, which are rapidly approaching the theoretical limit of their efficiency. Current DSSC designs, however, are only about 10 percent efficient.

One reason for this low efficiency is that light from the infrared portion of the spectrum is not easily absorbed in the solar cell. The new layered design, as described in the AIP's Journal of Renewable and Sustainable Energy, increases the path of the light through the solar cell and converts more of the electromagnetic spectrum into electricity. The cells consist of micrometer-scale spheres with nanometer pores sandwiched between layers of nanoscale particles. The spheres, which are made of TiO2, act like tightly packed bumpers on a pinball machine, causing photons to bounce around before eventually making their way through the cell.

Each time the photon interacts with one of the spheres, a small charge is produced. The interfaces between the layers also help enhance the efficiency by acting like mirrors and keeping the light inside the solar cell where it can be converted to electricity. This strategy to increase light-harvesting efficiency can be easily integrated into current commercial DSSCs.


Story Source:

The above post is reprinted from materials provided by American Institute of Physics. Note: Materials may be edited for content and length.


Journal Reference:

  1. Bin Liu, Eray S. Aydil. Layered mesoporous nanostructures for enhanced light harvesting in dye-sensitized solar cells. Journal of Renewable and Sustainable Energy, 2011; 3 (4): 043106 DOI: 10.1063/1.3615641

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American Institute of Physics. "Solar cells get a boost from bouncing light." ScienceDaily. ScienceDaily, 2 August 2011. <www.sciencedaily.com/releases/2011/07/110729175554.htm>.
American Institute of Physics. (2011, August 2). Solar cells get a boost from bouncing light. ScienceDaily. Retrieved August 28, 2015 from www.sciencedaily.com/releases/2011/07/110729175554.htm
American Institute of Physics. "Solar cells get a boost from bouncing light." ScienceDaily. www.sciencedaily.com/releases/2011/07/110729175554.htm (accessed August 28, 2015).

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