Controlling singlet–triplet splitting in carbazole–oxadiazole based bipolar phosphorescent host materials

Kautny, Paul; Wu, Zhongbin; Stöger, Berthold; Tissot, Antoine Michel; Horkel, Ernst; Chen, Jiangshan; Ma, Dongge; Hagemann, Hans-Rudolf; Fröhlich, Johannes; Lumpi, Daniel

doi:10.1016/j.orgel.2014.11.027

Scientific article

English

Controlling singlet–triplet splitting in carbazole–oxadiazole based bipolar phosphorescent host materials

Contributors

Kautny, Paul; Wu, Zhongbin; Stöger, Berthold; Tissot, Antoine Michel; Horkel, Ernst; Chen, Jiangshan; Ma, Dongge; Hagemann, Hans-Rudolf; Fröhlich, Johannes; Lumpi, Daniel

Published in

Organic electronics, vol. 17, p. 216-228

Publication date

2015

Abstract

A rational molecular design strategy for carbazole–oxadiazole based bipolar host materials was developed to improve the device efficiency of blue phosphorescent organic light-emitting diodes (PHOLED). Steric effects of strategically placed methyl groups led to an increase of triplet energies (o-2MPCzPOXD: 2.66 eV and o-3MPCzPOXD: 2.73 eV versus the initial host material o-PczPOXD: 2.62 eV) while less pronouncedly affecting singlet energies and, therefore, retaining low driving voltages, high power efficiencies and remarkably low efficiency roll-offs in PHOLEDs. The maximum quantum efficiencies (EQE) for blue devices (FIrpic) were significantly raised for o-2MPCzPOXD (13.6%) and o-3MPCzPOXD (11.5%) versus o-PCzPOXD (9.0%) although yielding comparable values for green devices (Ir(ppy)3; 12.9% and 15.4% versus 13.2%). Supported by theoretical calculations a structure–property relationship was established from photo-physical properties, PHOLED performance measurements and structural characterization from single crystal data.

UNIGE affiliation entities

Faculté des sciences / Section de chimie et biochimie / Département de chimie physique

UNIGE research groups

Groupe Hagemann

Citation (ISO format)

KAUTNY, Paul et al. Controlling singlet–triplet splitting in carbazole–oxadiazole based bipolar phosphorescent host materials. In: Organic electronics, 2015, vol. 17, p. 216–228. doi: 10.1016/j.orgel.2014.11.027

Article (Published version)

Identifiers

PID : unige:44949
DOI : 10.1016/j.orgel.2014.11.027

Additional URL for this publication

http://linkinghub.elsevier.com/retrieve/pii/S1566119914005497

Journal ISSN

1566-1199

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08/01/2015 09:06:00

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Controlling singlet–triplet splitting in carbazole–oxadiazole based bipolar phosphorescent host materials

Contributors

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Abstract

UNIGE affiliation entities

UNIGE research groups

Citation (ISO format)

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First validation

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