The University of Southampton
University of Southampton Institutional Repository

High performance organic light emitting diodes using substoichiometric tungsten oxide as efficient hole injection layer

High performance organic light emitting diodes using substoichiometric tungsten oxide as efficient hole injection layer
High performance organic light emitting diodes using substoichiometric tungsten oxide as efficient hole injection layer

In this work we demonstrate the unique hole injection and transport properties of a substoichiometric tungsten oxide with precise stoichiometry, in particular WO2.5, obtained after the controlled hydrogen reduction during growth of tungsten oxide, using a simple hot-wire vapor deposition technique. We present clear evidence that tungsten suboxide exhibits metallic character and that an almost zero hole injection barrier exists at the anode/polymer interface due to the formation/occupation of electronic gap states near the Fermi level after oxide's reduction. These states greatly facilitate hole injection and charge generation/electron extraction enabling the demonstration of extremely efficient hole only devices. WO2.5 films exhibit metallic-like conductivity and, thus, can also enhance charge transport at both anode and cathode interfaces. Electroluminescent devices using WO 2.5 as both, hole and electron injection layer, and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)] (F8BT) as the emissive layer exhibited high efficiencies up to 7 cd/A and 4.5 lm/W, while, stability studies revealed that these devices were extremely stable, since they were operating without encapsulation in air for more than 700 h.

Efficient hole injection, Metallic suboxides, Organic light emitting diodes, Reduced metal oxides, Transition metal oxides
1566-1199
796-806
Vasilopoulou, Maria
aad1381e-d091-4090-8c7c-b74bed22393d
Papadimitropoulos, George
b4f1ecba-cc8a-4882-99a5-a29354a9bca7
Palilis, Leonidas C.
b09e9554-54da-4be5-aa08-bda894e2b86f
Georgiadou, Dimitra G.
84977176-3678-4fb3-a3dd-2044a49c853b
Argitis, Panagiotis
ab9c4ea6-3dd2-4e34-935d-81bfb360f358
Kennou, Stella
7ca6a6bd-6a05-4110-b3da-c8807f798370
Kostis, Ioannis
681af9a6-5162-4f35-b6b1-365ea7ce7e47
Vourdas, Nikolaos
ec93034a-20d9-4d15-b691-084f29601a3e
Stathopoulos, Nikolaos A.
83a4653f-c4c8-464a-8ed1-a93c52cf3833
Davazoglou, Dimitris
a946cf5d-287a-4734-ba55-b180ab4525ed
Vasilopoulou, Maria
aad1381e-d091-4090-8c7c-b74bed22393d
Papadimitropoulos, George
b4f1ecba-cc8a-4882-99a5-a29354a9bca7
Palilis, Leonidas C.
b09e9554-54da-4be5-aa08-bda894e2b86f
Georgiadou, Dimitra G.
84977176-3678-4fb3-a3dd-2044a49c853b
Argitis, Panagiotis
ab9c4ea6-3dd2-4e34-935d-81bfb360f358
Kennou, Stella
7ca6a6bd-6a05-4110-b3da-c8807f798370
Kostis, Ioannis
681af9a6-5162-4f35-b6b1-365ea7ce7e47
Vourdas, Nikolaos
ec93034a-20d9-4d15-b691-084f29601a3e
Stathopoulos, Nikolaos A.
83a4653f-c4c8-464a-8ed1-a93c52cf3833
Davazoglou, Dimitris
a946cf5d-287a-4734-ba55-b180ab4525ed

Vasilopoulou, Maria, Papadimitropoulos, George, Palilis, Leonidas C., Georgiadou, Dimitra G., Argitis, Panagiotis, Kennou, Stella, Kostis, Ioannis, Vourdas, Nikolaos, Stathopoulos, Nikolaos A. and Davazoglou, Dimitris (2012) High performance organic light emitting diodes using substoichiometric tungsten oxide as efficient hole injection layer. Organic Electronics, 13 (5), 796-806. (doi:10.1016/j.orgel.2012.01.008).

Record type: Article

Abstract

In this work we demonstrate the unique hole injection and transport properties of a substoichiometric tungsten oxide with precise stoichiometry, in particular WO2.5, obtained after the controlled hydrogen reduction during growth of tungsten oxide, using a simple hot-wire vapor deposition technique. We present clear evidence that tungsten suboxide exhibits metallic character and that an almost zero hole injection barrier exists at the anode/polymer interface due to the formation/occupation of electronic gap states near the Fermi level after oxide's reduction. These states greatly facilitate hole injection and charge generation/electron extraction enabling the demonstration of extremely efficient hole only devices. WO2.5 films exhibit metallic-like conductivity and, thus, can also enhance charge transport at both anode and cathode interfaces. Electroluminescent devices using WO 2.5 as both, hole and electron injection layer, and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)] (F8BT) as the emissive layer exhibited high efficiencies up to 7 cd/A and 4.5 lm/W, while, stability studies revealed that these devices were extremely stable, since they were operating without encapsulation in air for more than 700 h.

Full text not available from this repository.

More information

Accepted/In Press date: 15 January 2012
e-pub ahead of print date: 31 January 2012
Keywords: Efficient hole injection, Metallic suboxides, Organic light emitting diodes, Reduced metal oxides, Transition metal oxides

Identifiers

Local EPrints ID: 440513
URI: http://eprints.soton.ac.uk/id/eprint/440513
ISSN: 1566-1199
PURE UUID: e70600f3-5f1c-40ae-b22b-755f2380adcc
ORCID for Dimitra G. Georgiadou: ORCID iD orcid.org/0000-0002-2620-3346

Catalogue record

Date deposited: 06 May 2020 16:30
Last modified: 07 Oct 2020 02:27

Export record

Altmetrics

Contributors

Author: Maria Vasilopoulou
Author: George Papadimitropoulos
Author: Leonidas C. Palilis
Author: Panagiotis Argitis
Author: Stella Kennou
Author: Ioannis Kostis
Author: Nikolaos Vourdas
Author: Nikolaos A. Stathopoulos
Author: Dimitris Davazoglou

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×