Solar Cells Taking A Leaf From Plants

There can be no doubt that solar energy is one of the cleanest, most efficient forms of renewable energy available to humans. It’s all natural – no burning, no dirty by-products, just pure energy streaming constantly from our solar system’s very own fusion reactor: the Sun. 
Plants have been harvesting this free energy for billions of years using photosynthesis to convert sunlight into food. Now a team from North Carolina State University have developed a type of solar photovoltaic "leaf" cell that mimics this process.
In a paper published in the online in the Journal of Materials Chemistry, NC State’s Dr. Orlin Velev, Invista Professor of Chemical and Biomolecular Engineering describes this new generation of solar cells as proving the concept of making solar photovoltaic cells that are more akin to plant than machine.
The bendable devices are composed of water-based gel infused with light-sensitive molecules – the researchers used plant chlorophyll in one of the experiments – coupled with electrodes coated by carbon materials, such as carbon nanotubes or graphite. The light-sensitive molecules are excited by the sun’s rays and produce electricity, similar to plant molecules that get excited to synthesize sugars in order to grow.
They also have the potential to be less expensive and more environmentally friendly than the current silicon-based solar cells.
Now that they’ve proven the concept, Velev says the researchers will work to fine-tune the water-based photovoltaic devices, making them even more like real leaves.
”The next step is to mimic the self-regenerating mechanisms found in plants," Velev says. "The other challenge is to change the water-based gel and light-sensitive molecules to improve the efficiency of the solar cells."