Full Paper
Origins of Low Quantum Efficiencies in Quantum Dot LEDs
Article first published online: 22 JAN 2013
DOI: 10.1002/adfm.201203191
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Issue

Advanced Functional Materials
Early View (Online Version of Record published before inclusion in an issue)
Additional Information
How to Cite
Bozyigit, D., Yarema, O. and Wood, V. (2013), Origins of Low Quantum Efficiencies in Quantum Dot LEDs. Adv. Funct. Mater.. doi: 10.1002/adfm.201203191
Publication History
- Article first published online: 22 JAN 2013
- Manuscript Revised: 4 DEC 2012
- Manuscript Received: 30 OCT 2012
Funded by
- Swiss National Science Foundation (SNSF)
- Electron Microscopy ETH Zurich
Keywords:
- light-emitting devices;
- quantum dots;
- core/shell nanoparticles;
- luminescence
Abstract
The promise for next generation light-emitting device (LED) technologies is a major driver for research on nanocrystal quantum dots (QDs). The low efficiencies of current QD-LEDs are often attributed to luminescence quenching of charged QDs through Auger-processes. Although new QD chemistries successfully suppress Auger recombination, high performance QD-LEDs with these materials have yet to be demonstrated. Here, QD-LED performance is shown to be significantly limited by the electric field. Experimental field-dependent photoluminescence decay studies and tight-binding simulations are used to show that independent of charging, the electric field can strongly quench the luminescence of QD solids by reducing the electron and hole wavefunction overlap, thereby lowering the radiative recombination rate. Quantifying this effect for a series of CdSe/CdS QD solids reveals a strong dependence on the QD band structure, which enables the outline of clear design strategies for QD materials and device architectures to improve QD-LED performance.

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