Origin of Efficiency Roll-Off in Colloidal Quantum-Dot Light-Emitting Diodes

Yasuhiro Shirasaki, Geoffrey J. Supran, William A. Tisdale, and Vladimir Bulović

Phys. Rev. Lett. 110, 217403 – Published 21 May 2013

Abstract

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.

Received 23 October 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.217403

Authors & Affiliations

Yasuhiro Shirasaki¹, Geoffrey J. Supran², William A. Tisdale³, and Vladimir Bulović¹

¹Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
²Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
³Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA