MIT researcher have made a self-healing solar cell that fixes its own UV damage.
According to the university, the chemical cell mimics nature where light-capturing molecules are constantly broken down and reassembled.
"I was really impressed by how plant cells have this extremely efficient repair mechanism," said chemical engineer Dr Michael Strano. In full summer sunlight, "a leaf on a tree is recycling its proteins about every 45 minutes, even though you might think of it as a static photocell."
That process has now been imitated by Strano's team with a set of self-assembling molecules that can turn sunlight into electricity.
"Strano says he believes this sets a record for the complexity of a self-assembling system," said the university.
He produced synthetic phospholipids molecules that provide structural support for proteins with reaction centres that release electrons when illuminated.
The phospholipids lipids are in a solution where they attach themselves spontaneously to carbon nanotubes which hold the phospholipids, and therefore the reaction centres, in uniform alignment and provide a conduction path for released electrons.
In total, there are seven compounds in the system, including the carbon nanotubes, phospholipids, and proteins.
When a surfactant is added to the mix, the seven components separate and form a soupy solution.
When the surfactant is removed by filtering, the compounds spontaneously assemble into a rejuvenated photocell.
Repeated cycles of assembly and disassembly over a 14 hour test showed no loss of efficiency, claimed MIT.
According to Strano, the individual reactions convert sunlight with about 40% efficiency and could theoretically approach 100%.
However, the concentration of the experimental structures in is low and the amount of electricity produced for a given surface area is "very low".
Photo: Strano's chemical mix is in the glass cylinder held in place by a metal clamp. The bare wire is a platinum electrode and the electrode in the glass tube is silver.