The Green Technocrat

The new world of solar technology is looming near.  Over the last few years researchers have started to have some limited of success building what are known as dye-sensitized solar cells. Solar cells that function by basically imitating the process of natural solar collection by plants and light-sensitive bacteria.

The cells are comprised of a semi-conductor (the most common of which is titanium dioxide), which is then coated with a dye that absorbs the sunlight.  When a photon of light with a specific quantity of energy is absorbed by the dye it causes what is called electron excitation (or simply excitation).  An electron absorbs the energy of the photon and moves to a higher energy state.  The excited electron travels towards the semi-conductor generating electricity when it arrives there.

Now a new breakthrough by researchers at Oregon State University might be bringing dye-sensitized PV cells to the forefront of solar technology.  Researchers at OSU have spent the last 5 years working on how to make dye-sensitized PV cells more affordable. and more efficient.  Their not so simple answer;  take advantage of the existence of an ancient single celled life form, whose exoskeleton happens to have the perfect nanostructure necessary to build the cells, thus eliminating the use of expensive silicon (which is used to construct most conventional types of solar cells), and tripling the electrical output (in comparison to other dye-sensitized cells).

The single celled organism in question are known as diatoms, microscopic organisms that are found in the fossil record as far back as the time of the dinosaurs. They are a key part of the marine food chain and help cycle carbon dioxide from the atmosphere.

The diatoms are allowed to from on a thin, conductive glass surface, and once they have covered the surface the living organic material (i.e. the organism itself) is removed leaving behind the exoskeleton.  Researchers then coat the exoskeleton with a thin film of titanium dioxide which acts as the semiconductor.

“Most existing solar cell technology is based on silicon and is nearing the limits of what we may be able to accomplish with that,” said Greg Rorrer, an OSU professor of chemical engineering working on the project.  Adding that, “Conventional thin-film, photo-synthesizing dyes also take photons from sunlight and transfer it to titanium dioxide, creating electricity, but in this system the photons bounce around more inside the pores of the diatom shell, making it more efficient.”

Once again nature proves to be a far better engineer than man.

Via ScienceDaily