Decoupled algae-powered solar cell has promise for rural communities

While most research into photovoltaic technology focuses on mineral-based mechanisms, from crystalline silicon to the promising perovskite materials, there are other possibilities. One of these exploits the most successful type of solar energy generation, photosynthesis, which has been powering the planet’s plants for aeons.

Biological solar cells generally use single-celled plants — algae — to harvest solar energy. The Cambridge team, comprising chemists, biochemists and physicists, now claims to have overcome one of the biggest obstacles to developing this technology: the conflicting demands of generating electrons and converting them into useful electric current.

Previous biophotovoltaics (BPVs) have co-located these two functions in the same chamber; algae absorb sunlight, generate electrons, some of which are secreted outside the algae’s cell walls, and immediately inject these electrons into an electrical circuit. But this is not an efficient method, explained Kadi Liis Saar, of the Department of Chemistry. “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.”