We’ve been hearing about cellulose as an energy producer in biofuels, but new research suggests the plant material could play a role in producing solar cells that would be a whole lot more green than conventional substrates materials – for one thing, you might be able to recycle them in water.

As usual, the challenge in turning this research into a reality will likely be in ratcheting up the efficiency of the solar cells.

solar power cellulose
image via Canek Fuentes-Hernandez, Georgia Tech

This work, out of Georgia Tech and Purdue University, is focused on fabricating solar cells on cellulose nanocrystal substrates instead of on the usual glass or plastic, both of which, the university noted, present a host of issues:

Neither is easily recyclable, and petroleum-based substrates are not very eco-friendly. For instance, if cells fabricated on glass were to break during manufacturing or installation, the useless materials would be difficult to dispose of. Paper substrates are better for the environment, but have shown limited performance because of high surface roughness or porosity.

So the goal here is to fashion substrates that aren’t just organic in the technical sense – made from carbon-based materials – but are organic in the sense that you and I think of the work: green.

“The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications,” Georgia Tech College of Engineering Professor Bernard Kippelen said. “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 the abstract of their paper, published in Scientific Reports, the researcher call cellulose nanomaterials “emerging high-value nanoparticles extracted from plants that are abundant, renewable, and sustainable.” (We’ve previously seen similar such materials

The polymer solar cells fabricated on optically transparent cellulose nanocrystal (CNC) substrates hit a power conversion efficiency of 2.7 percent. That’s a long way from, say, the 18.7 efficiency First Solar just achieved with ca admium-telluride cell.  (Mind you, panel efficiencies are lower, with the First Solar thin-film module at 14.4 percent.)

“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,” Kippelen said. The group plans to achieve this by optimizing the optical properties of the solar cell’s electrode.

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