System uses photosynthesis to produce efficient solar energy

Researchers from Tennessee University collaborated with the Massachusetts Institute of Technology and École Polytechnique Fédérale in Switzerland to develop a process that improves the efficiency of generating electric power using molecular structures extracted from plants.

Prof Barry Bruce, project leader from Tennessee University, said: ‘As opposed to conventional photovoltaic solar power systems, we are using renewable biological materials rather than toxic chemicals to generate energy. Likewise, our system will require less time, land, water and input of fossil fuels to produce energy than most biofuels.’

To produce the energy, the scientists harnessed the power of a key component of photosynthesis known as photosystem-I (PSI) from blue-green algae.

This complex was then bioengineered to specifically interact with a semiconductor so that, when illuminated, the process of photosynthesis produced electricity.

The green solar cell consists of small tubes made of zinc oxide that are bioengineered to attract PSI particles and quickly become coated with them.

Done correctly, the two materials intermingle on the metal oxide interface, which, when illuminated by sunlight, excites PSI to produce an electron that ‘jumps’ into the zinc oxide semiconductor — producing an electric current.

The mechanism needs to be further developed in order to become useful. However, the approach is simple enough that it can be replicated in most labs, allowing others around the world to work towards further optimisation.

The results were published in Nature: Scientific Reports.