Crystals of photosynthetic protein complexes extracted from plant cells can generate extraordinarily high voltages when placed on a conducting surface and stimulated by light.

Each of the light-transducing complexes known as photosystem I can generate about 1 volt during photosynthesis in the plant. Nathan Nelson and his colleagues at Tel Aviv University measured the electrical potential produced in crystals containing hundreds of layers of photosystem I placed on gold, silicon carbide, or indium tin oxide surfaces. The complexes lined up head to toe, like batteries connected in series. The material produced up to 45 volts when illuminated with laser light, and also generated internal electric fields of up to 100 kilovolts per centimetre — among the strongest ever reported in a crystalline material, even among inorganic semiconductors.

The researchers say that the material could be used to make more efficient high-voltage optoelectronic devices.

Adv. Mater. http://dx.doi.org/10.1002/adma.201200039 (2012)