Origin of efficiency roll-off in colloidal quantum-dot light-emitting diodes

Phys Rev Lett. 2013 May 24;110(21):217403. doi: 10.1103/PhysRevLett.110.217403. Epub 2013 May 21.


We study the origin of efficiency roll-off (also called "efficiency droop") in colloidal quantum-dot light-emitting diodes through the comparison of quantum-dot (QD) electroluminescence and photoluminescence. We find that an electric-field-induced decrease in QD luminescence efficiency-and not charge leakage or QD charging (Auger recombination)-is responsible for the roll-off behavior, and use the quantum confined Stark effect to accurately predict the external quantum efficiency roll-off of QD light-emitting diodes.