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Electroluminescent Cu-doped CdS Quantum Dots by Jan W. Stouwdam; René A. J. Janssen is a Engineering article available to read on EtoBox.

Semiconductor quantum dot light-emitting diodes (QD-LEDs) allow easy color tuning by changing the QD size. [1] Similar to organic LEDs (OLEDs) based on phosphorescent molecules, QD-LEDs do not suffer from the spin statistics that limit the internal quantum efficiency of fluorescent OLEDs. Nevertheless, the efficiency of current QD-LEDs is far less compared to state-of-the-art phosphorescent OLEDs, like those based on iridium emitters. [2] Early QD-LEDs used CdSe as the emitter in a poly(N-vinylcarbazole)/2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3, 4-oxadiazole (PVK/PBD) matrix, but these devices showed very low external quantum efficiency (h ext % 0.0005%). A somewhat higher efficiency (h ext % 0.001-0.01%) was obtained in a layered device, where a layer of CdSe QDs was spin cast on a layer of poly( p-phenylene vinylene) (PPV). The efficiency of these layered devices was further enhanced to h ext 1⁄4 0.22%, by using QDs with a CdSe core and a CdS shell. Additional progress in the efficiency of QD-LEDs was achieved by changing the polymer layer, introducing an electron injection layer, and optimizing the thickness of the QD layer, resulting in efficiencies of h ext 1⁄4 2%. Rece

Author

Jan W. Stouwdam; René A. J. Janssen

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); Wiley-Blackwell; Wiley; Research Square (ISSN 0935-9648)

Published

2009

Language

EN

Field

Engineering (Physical Sciences)