White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers

Tim Schaefer; Tobias Schwab; Simone Lenk; Malte Christian Gather

doi:10.1063/1.4937004

White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers

Tim Schaefer, Tobias Schwab, Simone Lenk, Malte Christian Gather

Research output: Contribution to journal › Letter › peer-review

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-particlescattering 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.

Original language	English
Article number	233301
Number of pages	5
Journal	Applied Physics Letters
Volume	107
DOIs	https://doi.org/10.1063/1.4937004
Publication status	Published - 7 Dec 2015

Keywords

Organic light emitting diodes
Solvent
Nanoparticles
Visible spectra
Light scattering

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Cite this

@article{9ad50cb3f2314e8c85ded76f8dbd6828,

title = "White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers",

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-particlescattering 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.",

keywords = "Organic light emitting diodes, Solvent, Nanoparticles, Visible spectra, Light scattering",

author = "Tim Schaefer and Tobias Schwab and Simone Lenk and Gather, {Malte Christian}",

note = "The authors are grateful to Novaled GmbH (Dresden) for financial support and material supply. M. C. Gather acknowledges financial support from the Scottish Founding Council through SUPA.",

year = "2015",

month = dec,

day = "7",

doi = "10.1063/1.4937004",

language = "English",

volume = "107",

journal = "Applied Physics Letters",

issn = "0003-6951",

publisher = "American Institute of Physics",

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TY - JOUR

T1 - White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers

AU - Schaefer, Tim

AU - Schwab, Tobias

AU - Lenk, Simone

AU - Gather, Malte Christian

N1 - The authors are grateful to Novaled GmbH (Dresden) for financial support and material supply. M. C. Gather acknowledges financial support from the Scottish Founding Council through SUPA.

PY - 2015/12/7

Y1 - 2015/12/7

N2 - 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-particlescattering 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.

AB - 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-particlescattering 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.

KW - Organic light emitting diodes

KW - Solvent

KW - Nanoparticles

KW - Visible spectra

KW - Light scattering

U2 - 10.1063/1.4937004

DO - 10.1063/1.4937004

M3 - Letter

SN - 0003-6951

VL - 107

JO - Applied Physics Letters

JF - Applied Physics Letters

M1 - 233301

ER -

White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers

Abstract

Keywords

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