Solar power has much to recommend it, not least that it’s clean and carbon-free. It also draws on an inexhaustible natural resources in the form of sun rays. It does have a significant drawback, though. It only works when the sun shines and in many places where solar energy can make a difference the sun often does not shine.
But some bacteria can come to the rescue. Researchers at the University of British Columbia, Canada, have co-opted genetically engineered E. coli bacteria that use dye to convert light into energy in order to create a so-called “biogenic” solar cell (a cell made of living organisms).
Their aim was to ensure that these new solar cells could continue to operate not only in bright but also in dim light. Better yet: it’s a cheap and sustainable solution to a vexing problem. Thanks to their invention, solar powers of the near future could operate at far higher efficiency in cloudy regions of the world such as British Columbia.
Solar cells serve the function of converting light into electrical current in solar panels. Earlier attempts to create biogenic solar cells have revolved around extracting certain natural dyes that bacteria use for photosynthesis. That dye is very good at gathering sunrays and converting them into energy. Extracting the dye, however, requires a complex and costly process that involves toxic solvents. There is also a risk that the dye itself might degrade during the extraction process.
Instead, what the Canadian researchers did was not to extract the dye from E. coli bacteria but leave it in them. The researchers coated the bacteria with a mineral to act as a semiconductor and applied the mixture to a glass surface. Presto: a biogenic solar cell. “With the coated glass acting as an anode at one end of their cell, [the bacteria] generated a current density of 0.686 milliamps per square centimeter [which was] an improvement on the 0.362 achieved by others in the field,” the university explains in a press release.
“We recorded the highest current density for a biogenic solar cell,” said Vikramaditya Yadav, a professor of chemical and biological engineering who led the project. “These hybrid materials that we are developing can be manufactured economically and sustainably, and, with sufficient optimization, could perform at comparable efficiencies as conventional solar cells.”
If applied to solar panels on an industrial scale, this invention could help make solar energy more economical, the scientists say.