MIT scientists have created what they say is the world's first practical 'artificial leaf', a solar cell the size of a playing card that mimics photosynthesis.
"A practical artificial leaf has been one of the Holy Grails of science for decades. We believe we have done it," says team leader Daniel Nocera.
"The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station."
Placed in a single gallon of water in bright sunlight, the device could produce enough electricity to supply a house in a developing country with electricity for a day, Nocera said.
It wrks by splitting water into hydrogen and oxygen, which are stored in a fuel celland used to produce electricity.
Artificial leaves have been around for a while - indeed, the first was created more than ten years ago. But existing versions tend to be expensive and have a short lifespan.
Nocera's new leaf is made of inexpensive materials that are widely available, works under simple conditions and is highly stable, he says. In laboratory studies, a prototype operated continuously for more than 45 hours without a drop in performance.
It's based on several newly-discovered catalysts, made of nickel and cobalt, that can efficiently split water into hydrogen and oxygen, under normal conditions. Right now, Nocera says his leaf is about 10 times more efficient at carrying out photosynthesis than a natural leaf - but says he's optimistic that he can boost efficiency much further.
"Nature is powered by photosynthesis, and I think that the future world will be powered by photosynthesis as well, in the form of this artificial leaf," he says.