It looks like Popeye is not the only one that gets a boost from spinach – an interdisciplinary team of researchers at Vanderbilt University have successfully extracted a protein called PS-1 from spinach (the green leafy vegetable), and combined it with silicon, to improve the power output of a solar cell.
The new discovery is reported to generate more power than what any other biohybrid solar cell has been shown to be capable of before, which indicates a new world record has just been set.
“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 biomolecular engineering. “If we can continue on our current trajectory of increasing voltage and current levels, we could reach the range of mature solar conversion technologies in three years.”
By extracting PS-1 from spinach into an aqueous solution, they could pour it onto a p-doped silicon wafer. The wafer was then put in vacuum, a process that evaporates all liquid from the material, leaving only PS-1 spread evenly across the surface left.
By exposing PS-1 to light, the energy absorbed “frees” electrons and sends them to the opposite side of the protein – much in the same way a traditional solar cell generates electricity.
The researcher has stated that their PS-1/silicon combo is generating 850 microamps for every square centimeter at 0.3 volts, which is over double what has been reported from biohybrid solar cells before. There is still a lot of research that has to be done before their idea is anywhere near market-competitiveness. The next step is to build a prototype based on their “spinach-wafer”-concept, which is exactly what some of the undergraduate students at Vanderbilt University will start working on.