You may consider yourself the greenest, most carbon-neutral person on your block, but get ready to take your ecological quest to a whole new level with recyclable solar cells made from trees.
Researchers from the Georgia Institute of Technology and Purdue University have fabricated efficient plant-based solar cells on cellulose nanocrystal substrates. Better yet, they can be dissolved in water and recycled.
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The organic solar cells have a power conversion efficiency of 2.7 percent, which researchers say is an unprecedented figure for cells created from renewable raw materials.
"Our next steps will be to work toward improving the power conversion efficiency over 10 percent, levels similar to solar cells fabricated on glass or petroleum-based substrates," Georgia Tech engineering professor Bernard Kippelen said in a university news release.
Organic solar cells are usually fabricated on glass or plastic, neither of which are easily recycled due to the manufacturing process. Petroleum-based substrates are even less eco-friendly. Substrates fabricated on paper are better for the environment, but because of high surface roughness or porosity, performance is limited. But cellulose nanomaterials have a low surface roughness and, because they're made from wood, they're green, renewable and sustainable.
Recycling these solar cells is as easy as immersing them in water at room temperature. It only takes a few minutes for the substrates to dissolve, then the solar cell can be separated into its major components.
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"The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications," said Kippelen, who is also the director of Georgia Tech's Center for Organic Photonics and Electronics (COPE). "But organic solar cells must be recyclable. Otherwise we are simply solving one problem, less dependence on fossil fuels, while creating another, a technology that produces energy from renewable sources but is not disposable at the end of its lifecycle."
Credit: Canek Fuentes-Hernandez/Georgia Tech