Efficient photovoltaic cells use biological healing process

Efficient photovoltaic cells use biological healing process

Researchers at MIT are working on a way to mimic the biological healing process employed by plants to naturally regenerate their cells after converting sunlight to energy. Over time, harvesting sunlight will gradually degrade many materials. However, plants are constantly breaking down their light-capturing molecules and reassembling them so that they are always new.

Michael Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering, and his team of graduate students and researchers, have worked to imitate the natural principles behind this process using nanocomponents. Specifically, these components are nanotubes that hold phospholipid disks. During photosynthesis, the proteins inside a plant’s chloroplasts react to the oxygen produced by sunlight, and fail in a very precise way. The same proteins are then quickly reassembled to restart the process.

Strano’s team imitated this natural process by producing synthetic molecules called phospholipids that form disks; the disks provide structural support for other molecules that actually respond to light in structures called reaction centers, which release electrons when struck by particles of light. The phospholipid disks carry the reaction centers, and are kept in a solution where they can spontaneously attach themselves to carbon nanotubes, which hold the disks in a uniform alignment so that the reaction centers can be exposed to sunlight all at the same time. The nanotubes also act as wires to collect and channel the flow of electrons knocked loose by the reactive molecules. Initial testing of the new molecular structures found that they are about 40% efficient in converting sunlight. The team continues to work on increasing the concentration. The team’s research was published on Sept. 5 in Nature Chemistry.

Christina D’Airo