New Cyanobacteria Solar Cells are CO2-Free, Nontoxic
Blue-green may be the color of tomorrow’s solar cell — a solar cell made without toxic materials that converts solar energy directly into electricity without emitting a single molecule of carbon dioxide. It turns out that cyanobacteria is very good at channeling solar energy into the biosphere. And by intercepting some of that energy, researchers at the University of Maryland, Baltimore (UMB) believe they can create solar electricity in a self-sustaining manner.
Cyanobacteria, which you may hear referred to as blue-green algae or blue-green bacteria, has natural electrogenic tendencies. That is, blue-green bacteria are naturally light-dependent, meaning that they inherently generate and transfer high-energy electrons into their environment when exposed to light. The microscopic organisms collectively store an estimated 25 giga-tons of carbon dioxide per year and are responsible for 20 to 30 percent of all photosynthetic activity on Earth. In other words, we have some powerful carbon-eating solar cells growing all around us.
Cyanobacteria exist in all environments, from the very hospitable to the unimaginable, from the heat of the Sahara desert to frozen Antarctica. Many different species exist. The solar energy they harness globally is upwards of 25 times the energy consumed by humans.
They harness that solar energy to drive photosynthesis, using it to split water molecules into oxygen, protons and electrons. The cyanobacteria use most of the electrons they create for their own purposes, but a small amount is released to the external environment. UMB researchers managed to develop what they call a photosynthetic microbial fuel cell (PMFC), which is both a growth chamber for the cyanobacteria and an electron harvester that collects that excess electricity released during photosynthesis.
Inside the PMFC, the bacteria grow directly on top of an anode, or conductive surface. When exposed to light, they emit electrons directly onto the anode, which can be collected for use by researchers. The process is much like that of any solar cell in existence, but instead of light striking a semiconductor (typically made from some metallic element, such as silicon, cadmium, indium, etc.), it strikes the bacteria, which require no energy to mine, refine or process.
For years now, solar researchers and scientists have been working to mimic photosynthesis in solar cell production, studying everything from sea slugs to fruit dyes.
Ilia Baskakov, associate professor at UMB’s Center for Biomedical Engineering, predicted that “in the future, the newly discovered physiological activity of cyanobacteria could be utilized for generating green electricity in a fully self-sustainable, CO2-free manner in the absence of any additional organic material.”
Could the fourth generation of solar cells be living solar cells?
Source: sify news Image: Wikipedia
Posted on June 22nd in Solar Research by Dan.