Many systems designed to capture sunlight also suffer from sunlight-induced degradation. Plants are the exception to this as they constantly break down their light-capturing molecules and reassemble them. A leaf recycles its proteins about every 45 minutes.

Michael Strano and colleagues, MIT, USA, have created a set of self-assembling phospholipids that display photoelectrochemical activity and can be repeatedly broken down and reassembled. These molecules form an array of lipid bilayers on the surface of carbon nanotubes. The nanotubes hold the phospholipids in a uniform alignment so that the protein-based reaction centers are exposed to sunlight simultaneously. The nanotubes also act as wires to collect and channel the electric current.

The self-assembled system disperses on addition of a surfactant. Removal of the surfactant reassembled the components into a photocell.

• Photoelectrochemical complexes for solar energy conversion that chemically and autonomously regenerate
  M.-H. Ham, J. H. Choi, A. A. Boghossian, E. S. Jeng, R. A. Graff et al.,
  Nat. Chem. 2010, 2.
  DOI: 10.1038/nchem.822