Using microscopic creatures as our friends is not a new idea, not it has been used recently. Nowadays, pushed by our green energy needs, we have to find solutions by using and probably killing some of our little friends to make us energy. This phrase sounded like the madhouse, now let’s get to the real subject.
Solar cells are commonly manufactured from silica, but they are expensive and inefficient. Dye-sensitized solar cells, on the other hand, are much cheaper, but they lack in efficiency more than silicon-based ones. As I vaguely suggested above, scientists from the Oregon State University have discovered a way of using mono-cellular living creatures to create more efficient dye-sensitized solar cells.
They used diatoms, an ancient form of marine life dating back to the age of dinosaurs, at least 100 million years. They are the basis of the oceans’ food chain, also having an important role in the ecosystem by sequestrating CO2 from the air. Although they are single-celled, diatoms have rigid shells, made of silica dioxide. Their shells have a unique nanostructure that can be used to better capture the light and trap it inside, giving the inefficient dye cells three times more power.
The scientists’ technological process is as follows:
1. the diatoms are allowed to settle on a transparent glass surface
2. the living organisms are removed, leaving behind tiny skeletons of the diatoms to form a template
3. a biological agent is used to precipitate liquid titanium into very tiny nanoparticles of titanium dioxide, creating a thin film that acts as the semiconductor for the dye-sensitized solar cell device. Steps that had been difficult to accomplish with conventional methods have been made easy through the use of these natural biological systems, using simple and inexpensive materials.
The scientists don’t yet understand the physics behind this process, as they discovered the phenomena experimentally, but it works.
Greg Rorrer, OSU professor of chemical engineering, says: “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.”
We’ll have to see if this technology will be kept updated in the next few and the tiny nano-shells will help us. Until then, we’re happy with another brilliant idea towards a more independent energy.
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