Recyclable, Efficient Solar Cells Created Using Trees
March 27, 2013

Recyclable, Efficient Solar Cells Created Using Trees

Lee Rannals for — Your Universe Online

Researchers have developed recyclable, efficient solar cells using natural substrates from plants like trees.

Georgia Institute of Technology and Purdue University researchers wrote in the journal Scientific Reports about how the solar cells can be quickly recycled in water at the end of their lifecycle. The team's solar cells are capable of reaching a power conversion efficiency of 2.7 percent.

During the recycling process, the solar cells are immersed in water at room temperature, and within minutes, the CNC substrates on which the solar cells are fabricated can be separated easily into its major components.

Georgia Tech College of Engineering Professor Bernard Kippelen, who led the study, said the method opens up 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,” Kippelen, who is also the director of Georgia Tech´s Center for Organic Photonics and Electronics (COPE), said in a statement. “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.”

Current organic solar cells are fabricated on glass or plastic, but neither is easily recyclable or very eco-friendly. If cells fabricated on glass were to break during the manufacturing process, the material would be difficult to dispose of. The team's cells are made from wood and are green, renewable and sustainable.

“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 US forest product industry projects that tens of millions of tons of cellulose nanomaterials from wood could be produced once large-scale production begins in the next five years.

Another new manufacturing method for producing solar cells was unveiled in the journal Advanced Materials in February. MIT researchers described a new process that allows scientists to passivate silicon at room temperatures, which helps with the high price of manufacturing computer chips and solar cells.

In the MIT team's process, they decompose organic vapors over wires heated to 572 degrees Fahrenheit. Heating these wires requires less power than illuminating an ordinary light bulb. This process not only opens the door for cheaper solar panels, but also new applications for computer chips.