Biogenic solar cells: working in dim conditions

Almost 8,000km from Beijing, Canadian researchers at the University of British Columbia (UBC) have designed ‘biogenic’ solar cells – using E.coli bacteria to transfer light to energy – which are said to work efficiently even in dim light conditions.

UBC scientists led by Vikramaditya Yadav, Professor at the Department of Chemical and Biological Engineering, discovered the cheap and sustainable method using bacteria. The team genetically engineered E.coli to produce considerable amounts of lycopene, a dye found in tomatoes that gives them their red colour, and makes them particularly effective at harvesting light.

The team coated E.coli bacteria with a semiconducting mineral and applied it to a glass surface, which acted as an anode at one end of their cell. Using this, they managed to generate a current of 0.686 milliamps per square centimetre (mA/cm2). This is an 89.5% increase on the previous record of 0.362mA/cm2 achieved by comparable designs in the field, according to Yadav.

They found that their version of the cell created a stronger electrical current than any previously recorded, noting that it worked just as efficiently in dim light as in bright light. Rolling out these organic PVs in places like Canada or Northern Europe could provide power during long periods of overcast skies.

Yadav said in a press release: “We recorded the highest current density for a biogenic solar cell. These hybrid materials that we are developing can be manufactured economically and sustainably, and, with sufficient optimisation, could perform at comparable efficiencies as conventional solar cells.”

He added that his team have optimised a process that was previously costly and complex. The UBC method of producing lycopene could reduce costs by up to 90%. He added that in the future, the team would aim to develop a process that does not inevitably kill the bacteria, enabling the production of lycopene indefinitely.