Perovskite Top Layer Could Boost Solar To Over 30 Efficiency And Cut Overall Costs In Half

The power conversion efficiency of silicon photovoltaics has been stuck at 25 percent for 15 years but cheap tandem solar cells could affordably boost efficiency.

One cost-effective way to improve efficiency is to build a tandem device made of silicon and another inexpensive photovoltaic material, he said.

"Making low-cost tandems is very desirable," McGehee said. "You simply put one solar cell on top of the other, and you get more efficiency than either could do by itself. From a commercial standpoint, it makes a lot of sense to use silicon for the bottom cell. Until recently, we didn't have a good material for the top cell, then pervoskites came along."

Perovskite is a crystalline material that is inexpensive and easy to produce in the lab. In 2009, scientists showed that perovskites made of lead, iodide and methylammonium could convert sunlight into electricity with an efficiency of 3.8 percent. Since then, researchers have achieved perovskite efficiencies above 20 percent, rivaling commercially available silicon solar cells and spawning widespread interest among silicon manufacturers.

When the Stanford group added perovskite to silicon solar cells whose efficiency was already 17 percent, for example, they measured a much smaller increase in power output, to 17.9 percent.

Even so, perovskites could be a boon for the solar industry. The researchers believe that perovskite-silicon cells will convert over 30 percent of the energy in sunlight into electricity. SUCH A BOOST WOULD CUT THE NUMBER OF SOLAR PANELS FOR SOME INSTALLATIONS ALMOST IN HALF, GREATLY LOWERING INSTALLATION COSTS.

Read more >>

Origin: clean-energy-technologies.blogspot.com