Perovskite LEDs begin to shine

As the key light-absorbing layer in solar cells, the cheap, easy to make materials called perovskites are adept at turning photons into electricity. Now, perovskites are turning the tables, converting electrons into light. Over the past 5 years, the efficiency at which perovskites convert electricity into light has surged from less than 1% to more than 21%. That now puts them on par with the efficiency of the commercial organic light-emitting diodes found in cellphones and flat screen TVs. And in a glimpse of how they might one day be harnessed, researchers reported last week in Science Advances that they've used a 3D printer to pattern perovskites for use in full-color displays.