Rensselaer Polytechnic Institute researchers have identified
the mechanism behind a plague of LED light bulbs: a flaw called “efficiency
droop” that causes LEDs to lose up to 20 percent of their efficiency as they
are subjected to greater electrical currents. Efficiency droop, first reported
in 1999, has been a key obstacle in the development of LED lighting for
situations, like household lighting, that call for economical sources of
versatile and bright light.