Auger effect identified as main cause of efficiency droop in LEDs

High-kinetic-energy electrons emitted from an LED clearly indicate that the Auger effect is the dominant cause of efficiency droop. Much of the cost of an LED lamp results from so-called efficiency droop: a decrease in the conversion efficiency of LEDs at high current densities. To maintain a high efficiency (lumens per watt), LED chips are operated at low current densities, which increases the number of LED chips needed for a given lumen output. Understanding the cause of efficiency droop is therefore of great interest, so that appropriate remedies can be developed.