September 27th, 2012 by Mathias
Algae have been on the Earth for almost 2 billion years. This is how long evolution has shaped these simple organisms to improve at what they do best: absorb sunlight. Algae derives most of it’s energy through a process called photosynthesis. One of the few critical components required is sunshine. Oxygen is one of the byproducts – in fact, marine algae produce about 75% of all the oxygen we breathe.
Scientists have long been fascinated by algae’s extreme capability to harness solar energy. In the last couple of years, research teams on various institutions across the globe have been looking at how we can boost the efficiency of solar cells by learning from algae.
If we looked at algae through the lens of an electron microscope, their shell or “skeleton” would reveal what characteristics makes them good at harnessing sunlight.
The orange “box” in the photograph above is actually a unicellular type of algae called a diatom. If you look at it’s upper surface you can see the shell is covered in small holes. This is only one of many similar layers that are stacked on top of each other making cylindrical holes into the organisms. These are large enough for nutrients to flow through, but stop dirt and filth to enter. This is also where photons are let through and bounce around much in the same way a pinball would do.
How on earth can this be applied to solar cells? It turns out that by putting these tiny algae skeletons on top of dye-sensitized solar cells, the photons are allowed more proximity to the photovoltaics, converting more sunlight into electricity.
A small research collaboration between Oregon State University and Portland State University announced that they were able to boost the output of solar cells enhanced with algae by as much as three times! Although very exciting news, these are laboratory conditions and whether similar experiments in real conditions will yield similar results is not clear at this point.
We can learn a lot by studying nature and applying mechanisms that are already put in place by natural selection to our own inventions. This has been done many times before scientists started working on algae-inspired solar cells. For two cool examples, check out how new solar trackers mimic sunflowers and spinach-based solar cells.
It will be interesting to see where the research is a couple of years from now, and if solar cells based on algae will eventually help bring solar panels’ cost down.
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