Blue photon discovery offers huge solar efficiency boost

Squabbling over solar subsidies could be a thing of the past if Cambridge researchers can successfully bring new high efficiency cells out from the lab and onto our roofs.

A significant jump in efficiency has been made that could see a 25 percent increase in energy transferred .

According to researchers at Cambridge University, the use of organic semiconductor materials in the production of solar cells has allowed more energy from the sun to be transferred into electricity than before.

By absorbing more of the light spectrum they believe the maximum possible efficiency rates could jump to 44 percent, up from 34 percent. In reality this could prove trickier as current solar cells are a long way from maximum efficiency levels.

But the method used by researchers has certainly opened up the door to significant increases in energy output.

This is because they have managed to harness the energy from blue photons that emanate as light from the sun.   Up until now, the blue photons have been lost to heat as sun rays hit solar panel rather than feeding in to lower your ‘leccy bill, with red photons more easily captured.

The addition of an organic semiconductor material called pentacene means that blue photons can be picked up, with two electrons produced for every blue photon that hits the solar cell.

Using the thin film, cells would have a number of advantages over bulky silicon based cells, though the main problem has been that they are unable to match efficiency levels.

But if it is possible to push up efficiency then it will mean that having to shell out for expensive silicon photovoltaic panels will not be necessary. Neither too would a feed in tariffs from DECC with the ability to save cash quickly increased.

One of the report authors, Dr. Akshay Rao, said the announcement was a “step towards a new generation of solar cells”.

Another of the scientists involved in the research, Bruno Ehrler, told TechEye that it will be a while still before the groundbreaking new cells are adorning our houses: “The hybrid solar cells we have made are in an early stage, in fact these are the first of their kind,” he told us. “So it is very difficult to estimate which way they take into commercialisation.”

Eight19, a production company spin off from Cambridge University, has agreed to manufacture the cells if they are found to be commercially viable.

“However,” Ehrler said, “in order to assess that we need to investigate the devices further. This might take 2-3 years.

“The route of commercialisation might also be a different one, e.g. augmenting conventional silicon solar cells with our organic material, pentacene, to harvest more of the energy of the blue photons.”

It is in thin film cells that the team are hoping to see development.

“Our materials can be dissolved and used as in ink in a roll-to-roll printing,” Ehrler says. “This allows for large scale production as well as for a variety of shapes and sizes and the production of flexible solar cells. The size and shape of a conventional silicon solar cell is pretty much fixed.”