Photovoltaic cells, the devices that make up solar panels, are made out of silicon. This semiconductor converts the light that strikes it into electricity. Scientists at the Massachusetts Institute of Technology(MIT) have isolated proteins from plant leaves that do just the same thing.
Plants turn light into energy to survive, that’s what they do, and it’s called photosynthesis. The parts of leaves involved in this process are called photosynthetic proteins. They have been known for a long time, but it was impossible to isolate them and make them work in an artificial environment. The team at the MIT managed to grow photosynthetic proteins from spinach leaves on a glass surface immersed in a conducting fluid. When light was shone on the proteins, they released electrons and created an electric current.
This is very exciting as it means that protein-based solar cells and electronic devices can be developed. This will reduce the amount of silicon and other artificial conductors, which are polluting to produce and need to be replaced every 20 years. Photosynthetic proteins are 100% natural, biodegradable and there’s no need to replace them since they regenerate by themselves.
HowStuffWorks on solar cells