Universität zu Köln

Schaefer, Tim, Schwab, Tobias, Lenk, Simone and Gather, Malte C. ORCID: 0000-0002-4857-5562 (2015). White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers. Appl. Phys. Lett., 107 (23). MELVILLE: AMER INST PHYSICS. ISSN 1077-3118

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Abstract

A random scattering approach to enhance light extraction in white top-emitting organic light-emitting diodes (OLEDs) is reported. Through solution processing from fluorinated solvents, a nano-particle scattering layer (NPSL) can be deposited directly on top of small molecule OLEDs without affecting their electrical performance. The scattering length for light inside the NPSL is determined from transmission measurements and found to be in agreement with Mie scattering theory. Furthermore, the dependence of the light outcoupling enhancement on electron transport layer thickness is studied. Depending on the electron transport layer thickness, the NPSL enhances the external quantum efficiency of the investigated white OLEDs by between 1.5 and 2.3-fold. For a device structure that has been optimized prior to application of the NPSL, the maximum external quantum efficiency is improved from 4.7% to 7.4% (1.6-fold improvement). In addition, the scattering layer strongly reduces the undesired shift in emission color with viewing angle. (C) 2015 AIP Publishing LLC.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schaefer, Tim UNSPECIFIED UNSPECIFIED UNSPECIFIED Schwab, Tobias UNSPECIFIED UNSPECIFIED UNSPECIFIED Lenk, Simone UNSPECIFIED UNSPECIFIED UNSPECIFIED Gather, Malte C. UNSPECIFIED orcid.org/0000-0002-4857-5562 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-383859
DOI:	10.1063/1.4937004
Journal or Publication Title:	Appl. Phys. Lett.
Volume:	107
Number:	23
Date:	2015
Publisher:	AMER INST PHYSICS
Place of Publication:	MELVILLE
ISSN:	1077-3118
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Physical Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EFFICIENCY; OLEDS; ELECTRODES; DEVICES; HYDROFLUOROETHERS; EMISSION Multiple languages Physics, Applied Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/38385