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Proceedings Paper

High-efficiency solution processed electrophosphorescent organic light emitting diodes based on a simple bi-layer device architecture
Author(s): Mathew Mathai; Vi-En Choong; Stelios A. Choulis; Franky So
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Paper Abstract

In this study molecular doping in non-conjugated polymeric systems is utilized in order to obtain high efficiency electrophosphorescent light emitting devices (PHOLEDs). The device consists of a light emitting thin film layer composed of hole and electron transporting moieties dispersed in a polymer matrix of polyvinylcarbazole (PVK). Light emission is obtained by harvesting singlet as well as triplet excitons by means of a phosphorescent dye, Iridium (III) tris(2-(4-tolyl)pyridinato-N,C2) (Ir(m-ppy)3), also dispersed in the polymer matrix. By incorporating a low conductivity polyethylene dioxythiophene-polystyrene-sulfonate (PEDOT) hole injection layer between the indium tin oxide transparent anode and the light emitting molecularly doped layer, the efficiency of these devices reaches values as high as 41 cd/A with a peak luminous efficacy of 28 lm/W. At the same time, triplet quenching by the hole transporting moiety as well as the electrodes are expected to be limiting the efficiency of these devices. In this paper we discuss several alternative device architectures studied in order to understand the factors affecting the device performance. In particular the effect of incorporating alternative hole transporting moieties and hole blocking layers are addressed.

Paper Details

Date Published: 9 October 2005
PDF: 7 pages
Proc. SPIE 5937, Organic Light-Emitting Materials and Devices IX, 59370C (9 October 2005); doi: 10.1117/12.617458
Show Author Affiliations
Mathew Mathai, OSRAM Opto Semiconductors Inc. (United States)
Vi-En Choong, OSRAM Opto Semiconductors Inc. (United States)
Stelios A. Choulis, OSRAM Opto Semiconductors Inc. (United States)
Franky So, OSRAM Opto Semiconductors Inc. (United States)

Published in SPIE Proceedings Vol. 5937:
Organic Light-Emitting Materials and Devices IX
Zakya H. Kafafi; Paul A. Lane, Editor(s)

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