Oregon Researchers Use Nano-shells of Algae to Trap Photons and Improve Solar Cell Efficiency

The Future of Energy will be based on our ability to elegantly control the interactions of light, carbon, hydrogen, oxygen and metals.  And for all our engineering prowress of extracting and blowing up ancient bio-energy reserves (coal/oil), there is still so much to learn about basic energy systems from Mother Nature.

Laying Down Algae Shells for Solar Panels
Researchers from Oregon State University and Portland State University have developed a new way to make “dye-sensitized” solar cells using a 'bottom up' biological assembly processes over traditional silicon chemical engineering.

The teams are working with a type of solar cell that generates energy when 'photons bounce around like they were in a pinball machine, striking these dyes and producing electricity.'

Rather than build the solar cells using traditional technqiues, the team is tapping the outer shells of single-celled algae, known as diatoms, to improve the electrical output. (Diatoms are believed to be the ancient bio-source of petroleum.)

The team placed the algae on a transparent conductive glass surface, and then (removed) the living organic material, leaving behind the tiny skeletons of the diatoms to form a template that is integrated with nanoparticles of titanium dioxide to complete the solar cell design.

Biology's Nanostructured Shells & Bouncing Photons?
“Conventional thin-film, photo-synthesizing dyes also take photons from sunlight and transfer it to titanium dioxide, creating electricity,” said Greg Rorrer, an OSU professor of chemical engineering “But in this system the photons bounce around more inside the pores of the diatom shell, making it more efficient.”

The research team is still not clear how the process works, but 'the tiny holes in diatom shells appear to increase the interaction between photons and the dye to promote the conversion of light to electricity... potentially with a triple output of electricity.' 

According to the team, this is the 'first reported study of using a living organism to controllably fabricate semiconductor TiO₂ nanostructures by a bottom-up self-assembly process.'  So, chalk up another early win for advanced bio-energy manufacturing strategies!