London, May 8 (IANS): A student from the University of Copenhagen has researched his way to a breakthrough that may prove pivotal for technologies trying to capture the energy of the sun and saving it for a rainy day.

Anders Bo Skov worked with special molecules capable of harvesting and holding substantial amounts of solar energy, storing it for significant amounts of time and releasing it on demand.

Earlier, regardless of what scientists did to prevent it, the molecules would change their shape back and release the stored energy after just an hour or two.

"Skov's achievement was that he managed to double the energy density in a molecule that can hold its shape for a hundred years," said professor Mogens Brondsted, Skov's supervisor.

"Our only problem now is how we get it to release the energy again. The molecule does not seem to want to change its shape back again," Brondsted grinned.

The group is working with molecules known as the Dihydroazulene-Vinylheptafulvene system.

Put simply, this stores energy by changing shape.

"My chemical 'recipe' demanded four synthesis steps in order to work. The first three were a piece of cake. I had them working in just a month. Getting the last step in order took me three months," Skov added.

His molecules are sustainable on more levels than just the obvious one.

Not only do they harvest sustainable solar energy, they are also completely non-toxic.

When it comes to storing solar power, the biggest competition comes from lithium ion batteries and lithium is a poisonous metal.

"My molecule releases neither CO2 nor any other chemical compounds while working. It is 'sunlight in-power out,'" he pointed out.

The paper is forthcoming in the journal Chemistry - A European Journal.