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Charge-carrier injection and transport in organic light-emitting diodes: Single-particle versus mean-field approach

Melzer, Christian and Genenko, Yuri A. and Yampolskii, Sergey V. and Stegmaier, Katja and Ottinger, Oliver M. and Seggern, Heinz von (2011):
Charge-carrier injection and transport in organic light-emitting diodes: Single-particle versus mean-field approach.
In: Journal of Photonics for Energy, pp. 011014-1-011014-9, 1, (1), ISSN 19477988, [Online-Edition: http://dx.doi.org/10.1117/1.3534762],
[Article]

Abstract

In the framework of the one-dimensional mean-field (MF) drift-diffusion approach the well-defined boundary conditions far away from the metal/insulator contacts of a planar metal/insulator/metal system are used to determine the boundary condition at the interface itself. The novel self-consistent boundary condition linking the carrier density and the electric field at the interface enables a straightforward description of the current voltage (IV) characteristics in forward and reverse bias bridging space charge and injection-limited regimes and accounting for barrier lowering from the potential drop in the used contact materials. Yet, because of the low carrier density in the insulator under injection limitation, single-particle phenomena, such as the Schottky effect, must be considered. We reconsider the validity of the MF approach, depending on the external bias and the prevailing injection barriers. For the crucial parameter window where the MF approach fails and single-particle phenomena become important, a modification of the boundary conditions at the insulator/metal interface is proposed to account for the discrete nature of carriers. The difference between the thus modified MF and the unmodified MF approach is illustrated by several examples.

Item Type: Article
Erschienen: 2011
Creators: Melzer, Christian and Genenko, Yuri A. and Yampolskii, Sergey V. and Stegmaier, Katja and Ottinger, Oliver M. and Seggern, Heinz von
Title: Charge-carrier injection and transport in organic light-emitting diodes: Single-particle versus mean-field approach
Language: English
Abstract:

In the framework of the one-dimensional mean-field (MF) drift-diffusion approach the well-defined boundary conditions far away from the metal/insulator contacts of a planar metal/insulator/metal system are used to determine the boundary condition at the interface itself. The novel self-consistent boundary condition linking the carrier density and the electric field at the interface enables a straightforward description of the current voltage (IV) characteristics in forward and reverse bias bridging space charge and injection-limited regimes and accounting for barrier lowering from the potential drop in the used contact materials. Yet, because of the low carrier density in the insulator under injection limitation, single-particle phenomena, such as the Schottky effect, must be considered. We reconsider the validity of the MF approach, depending on the external bias and the prevailing injection barriers. For the crucial parameter window where the MF approach fails and single-particle phenomena become important, a modification of the boundary conditions at the insulator/metal interface is proposed to account for the discrete nature of carriers. The difference between the thus modified MF and the unmodified MF approach is illustrated by several examples.

Journal or Publication Title: Journal of Photonics for Energy
Volume: 1
Number: 1
Uncontrolled Keywords: carrier density, diffusion, metal-insulator boundaries, MIM structures, organic light emitting diodes, organic semiconductors, Schottky barriers
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > C - Modelling > Subproject C5: Phenomenological modelling of injection, transport and recombination in organic semiconducting devices as well as in inorganic ferroelectric materials
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > D - Component properties > Subproject D4: Fatigue of organic electronic devices
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > C - Modelling
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > D - Component properties
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 16 Sep 2011 08:03
Official URL: http://dx.doi.org/10.1117/1.3534762
Additional Information:

SFB 595 Cooperation C5,D4

Identification Number: doi:10.1117/1.3534762
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