Organic solar substrate that literally grows on trees

The field of organic solar cells has shown in recent times, for short lifetime, low cost applications. New research from Georgia Tech’s Center for Organic Photonics and Electronics (COPE) and Purdue University that utilizes a cellulose-based natural substrate. The cells only have an efficiency of 2.7%, but it does represent an improvement on previous attempts at using paper-based or natural substrates.

The advantages of the new solar cells, claim the researchers, is the substrate can be easily recycled, is not petroleum-based and is inexpensive.

"The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications," said Professor Bernard Kippelen, project leader and director of COPE, to Forbes. "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."

In laboratory tests, the organic solar cell developed by the COPE researchers dissolves in 30 minutes when immersed in water. The CNC substrate is then left as a solid residue as the water evaporates and can then be recycled.

The CNC substrate is transparent, which allows light pass through onto the organic semiconductor layer.

The researchers now intend to increase the conversion efficiency of the solar cells, which they hope can be raised to the level of organic photovoltaics that utilize glass or petroleum-based substrates. The paper delivering the results concludes: "Efficient and easily recyclable polymer solar cells on cellulose nanocrystal substrates could be an ideal technology for sustainable, scalable and environmentally-friendly energy production and could have an overreaching impact for the sustainability of printed electronics."

German company Heliatek has claimed the current orgnaic photovoltaic efficiency record of 12%.