To date, organic solar cells have been typically fabricated on glass or plastic. Neither is easily recyclable, and petroleum-based substrates are not very eco-friendly.
We have reported about a lot of innovations surrounding solar cells but this one will surely take you by surprise. Georgia Institute of Technology and Purdue University researchers have developed efficient solar cells using natural substrates derived from plants such as trees. What makes the news even more exciting is that the researchers have managed to recycle them in water by fabricating them on cellulose nanocrystal (CNC) substrates. To date, organic solar cells have been typically fabricated on glass or plastic. Neither is easily recyclable, and petroleum-based substrates are not very eco-friendly.
The researchers report that the organic solar cells reach a power conversion efficiency of 2.7 per cent, an unprecedented figure for cells on substrates derived from renewable raw materials. The CNC substrates on which the solar cells are fabricated are optically transparent, enabling light to pass through them before being absorbed by a very thin layer of an organic semiconductor. During the recycling process, the solar cells are simply immersed in water at room temperature. Within only minutes, the CNC substrate dissolves and the solar cell can be separated easily into its major components, the press release on Georgia Tech states.
The study was led by Engineering Professor Bernard Kippelen who says that his team’s project opens the door for a truly recyclable, sustainable and renewable solar cell technology. “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.”
“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,” said Kippelen. The group plans to achieve this by optimising the optical properties of the solar cell’s electrode.
A provisional patent on the technology has been filed with the U.S. Patent Office.