Wonder solar cells to produce cheap laser too!

In a revolutionary find, British researchers have discovered that a new type of solar cells excel not just at absorbing light but also at emitting it.

It means that these 'wonder' solar cells can produce cheap lasers - opening a new field for using this material in telecommunications and light-emitting devices.

"This first demonstration of lasing in these cheap solution-processed semiconductors opens up a range of new applications," said lead author Felix Deschler of the Cavendish Laboratory at Cambridge University.

This new type of solar cell based on a perovskite material - named for scientist Lev Perovski - was recently pioneered by an Oxford research team led by Professor Henry Snaith.

Perovskite solar cells already lie just a fraction behind commercial silicon - having reached a remarkable 17 percent efficiency after a mere two years of research.

This holds promise towards generating cheap solar energy for better use at homes in a larger area, scientists say.

By sandwiching a thin layer of the lead halide perovskite between two mirrors, the team produced an optically-driven laser which proves these cells "show very efficient luminescence" with up to 70 percent of absorbed light re-emitted.

"It is thrilling to find that perovskite cells can overtake commercial silicon-based solar cells - such as those seen on the roofs of houses across the country - in terms of efficiency after just two years of development," Sam Stranks, co-author from the Oxford University team, added.

Most commercial solar cell materials need expensive processing to achieve a very low level of impurities before they show good luminescence and performance.

Surprisingly, these new materials work well even when very simply prepared as thin films using cheap scalable solution processing.

"We were surprised to find such high luminescence efficiency in such easily prepared materials. This has great implications for improvements in solar cell efficiency," Michael Price, co-author from the group in Cambridge, noted.

Commercial silicon-based solar cells operate at about 20 percent efficiency for converting sun rays into electrical energy.

It took over 20 years to achieve that rate of efficiency.

The new findings were recently published in the Journal of Physical Chemistry Letters.