When we hear “spinach power” we are more likely to think about Popeye the sailor, rather than clean energy. But researchers at the Vanderbilt University have developed a way to combine the photosynthetic protein that converts light into electrochemical energy in spinach with silicon, the material used in solar cells, in a fashion that produces substantially more electrical current than has been reported by previous “bio-hybrid” solar cells.
About 40 years ago, scientists discovered that one of the proteins involved in photosynthesis, called Photosystem 1 (PS1), continued to function when it was extracted from plants like spinach. Then they determined PS1 converts sunlight into electrical energy with nearly 100 percent efficiency, compared to conversion efficiencies of less than 40 percent achieved by man-made devices. This prompted various research groups around the world to begin trying to use PS1 to create more efficient solar cells.
Another potential advantage of these bio-hybrid cells is that they can be made from cheap and readily available materials, unlike many microelectronic devices that require rare and expensive materials like platinum or indium. Most plants use the same photosynthetic proteins as spinach.
“This combination produces current levels almost 1,000 times higher than we were able to achieve by depositing the protein on various types of metals. It also produces a modest increase in voltage,” said David Cliffel, associate professor of chemistry, who collaborated on the project with Kane Jennings, professor of chemical and bio molecular engineering.
Researchers say that if they could continue on the current trajectory of increasing voltage and current levels, they could reach the range of mature solar conversion technologies in three years.