The new cell converts 22.4% of the incoming energy from the sun, a record in power conversion efficiency for a perovskite–CIGS tandem solar cell. The performance was confirmed in independent tests at the U.S. Department of Energy's National Renewable Energy Laboratory.
The cell's CIGS base layer, which is about 2 microns (or two-thousandths of a millimeter) thick, absorbs sunlight and generates energy at a rate of 18.7 percent efficiency on its own, but adding the 1 micron-thick perovskite layer improves its efficiency — much like how adding a turbocharger to a car engine can improve its performance. The two layers are joined by a nanoscale interface that the UCLA researchers designed; the interface helps give the device higher voltage, which increases the amount of power it can export.
And the entire assembly sits on a glass substrate that's about 2 millimeters thick.