Colloidal quantum-dot light-emitting diodes with metal-oxide charge transport layers

Publication Type:

Journal Article

Source:

Nat. Photonics, Nature Publishing Group, Volume 2, Issue 4, p.247-250 (2008)

ISBN:

1749-4885

Keywords:

2008, 2013 and earlier

Abstract:

Colloidal quantum dots, with their tunable luminescence properties, are uniquely suited for use as lumophores in light-emitting devices for
display technologies and large-area planar lighting1, 2, 3, 4, 5, 6, 7, 8,
9, 10. In contrast to epitaxially grown quantum dots, colloidal quantum
dots can be synthesized as highly monodisperse colloids and solution
deposited over large areas into densely packed, solid-state multilayers,
which have shown promise as efficient optical gain media11. To be a viable
platform for colour-tunable electrically pumped lasers, the
present-generation quantum-dot LEDs must be modified to withstand the
extended, high-current-density operation needed to achieve population
inversion. This requirement necessitates a quantum-dot LED design that
incorporates robust charge transport layers. Here we report the use of
sputtered, amorphous inorganic semiconductors as robust charge transport
layers and demonstrate devices capable of operating at current densities
exceeding 3.5 A cm- 2 with peak brightness of 1,950 Cd m- 2 and maximum
external electroluminescence efficiency of nearly 0.1% , which represents
a 100-fold improvement over previously reported structures8, 10.