New research has shown that wrinkles on the surface of an organic solar cell can not only help boost performance considerably but can also be straightforward to implement, perhaps bringing organic solar cells one step closer to wider-scale commercial development.

The recent article in Nature Photonics states that the researchers took their inspiration from the natural world where some of the most basic light-harvesting structures rely on the small-scale variation in the morphology of surfaces.  A wide variety of light absorption enhancing surface structures are possible but many of those examined so far in the research literature require complex laboratory techniques. In some cases, this limits the potential for future commercialization.

In contrast to this research are surface structures like wrinkles and folds. They are something that occurs naturally as a material responds to stresses and strains and they may therefore be a cheap but useful way for improving the light-harvesting capabilities of certain types of solar cells.

The wrinkles on the surface of an organic solar cell bends light into the solar cell, forcing it to travel a longer distance inside the cell and enhancing absorption (Picture credit: Ref. at bottom).

The technique is conceptually straightforward.  Stresses and strains are applied to a substrate such that it develops wrinkles and folds on its surface. The organic solar cell is then deposited on top of this substrate and the surface pattern is imprinted into the solar cell. This allowed the Princeton researchers to create a solar cell that produced 47% more electric current than a comparably flat surface.

So next time somebody tells you that wrinkles are a bad thing; you can make sure to correct them.

-Erik Janssen

(Engineering Physics, MASc, Year 2 at McMaster University)

Article:

Wrinkles and deep folds as photonic structures in photovoltaics. Nature photonics, Vol 6. May 2012.

http://www.nature.com/nphoton/journal/v6/n5/full/nphoton.2012.70.html

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