“Plant” Solar Cells Have Chlorophyll-Like Compound To Capture Sunlight

Inspired by nature’s successful strategy, researchers have used materials similar to chlorophyll in leaves to develop low-cost and high-efficiency solar cells for the next generation of clean energy technologies.

AsianScientist (Nov. 22, 2011) – Plants have been using dyes to absorb sunlight and turn it into energy since their first appearance on earth. The dye molecules release electrons when sunlight hits, generating an energy flow which is stored in chemical bonds.

Inspired by nature’s successful strategy, researchers have turned their focus to materials that are similar to chlorophyll in leaves to develop low-cost and high-efficiency solar cells for the next generation of clean energy technologies.

Although dye-sensitized solar cells (DSC) have received great attention due to their simpler fabrication procedures and lower cost compared to silicon-based ones, their efficiency is lower by a factor of two.

Previously, scientists and manufacturers included the expensive and rare element ruthenium in their DSCs but the energy yield was low.

In a new report in the journal Science, the research team lead by Dr. Michael Grätzel of the Swiss Federal Institute of Technology in Lausanne, in collaboration with Dr. Chen-Yu Yeh of National Chung Hsing University and Dr. Wei-Guang Diau of National Chiao Tung University in Taiwan, has made a breakthrough by bring the efficiency of sunlight conversion to about 13 percent, closer to the 20 percent achieved by silicon-based solar cells.

The team discovered that by incorporating a zinc-bearing compound from the group of porphyrins, known for hemes in the blood that catches oxygen and chlorophyll in plants, the device absorbs light better and more cost-effectively.

This patented technology may potentially be available for commercial use someday, and may bring down the costs of solar energy by replacing silicon-based solar cells.

The article can be found at: Yella A et al. (2011) Porphyrin-Sensitized Solar Cells with Cobalt (II/III)–Based Redox Electrolyte Exceed 12 Percent Efficiency.

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Copyright: Asian Scientist Magazine.
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Hsin-Jung Sophia Li is a Ph.D. student at Princeton University. She received a S.B. degree with double majors in Chemical Engineering and Biology from MIT. She is a first dan black belt in Taekwondo and loves traveling around the world. Her research interests are systems biology and molecular cell biology.

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