Biophotovoltaics (BPVs) biological solar cells use the photosynthetic properties of microorganisms such as algae and microfluidics to convert light into electric current that can be used to provide electricity. During photosynthesis, algae produce electrons, some of which are exported outside the cell where they can provide electric current to power devices. So far, all the BPVs demonstrated have located charging (light harvesting and electron generation) and power delivery (transfer to the electrical circuit) in a single compartment.
These differ from microbial fuel cells (MFCs) that use bateria to generate power from waste water.
The team from the departments of Biochemistry, Chemistry and Physics developed a two-chamber BPV system where the two core processes involved in the operation of a solar cell - generation of electrons and their conversion to power - are separated.
"Charging and power delivery often have conflicting requirements," said Kadi Liis Saar from the Department of Chemistry. "For example, the charging unit needs to be exposed to sunlight to allow efficient charging, whereas the power delivery part does not require exposure to light but should be effective at converting the electrons to current with minimal losses."
The two-chamber architecture allowed the researchers to design the two units independently and so optimise the performance of both processes simultaneously.