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Electrical and optical simulations of a polymer-based phosphorescent organic light-emitting diode with high efficiency

  • A comprehensive numerical device simulation of the electrical and optical characteristics accompanied with experimental measurements of a new highly efficient system for polymer-based light-emitting diodes doped with phosphorescent dyes is presented. The system under investigation comprises an electron transporter attached to a polymer backbone blended with an electronically inert small molecule and an iridium-based green phosphorescent dye which serves as both emitter and hole transporter. The device simulation combines an electrical and an optical model. Based on the known highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of all components as well as the measured electrical and optical characteristics of the devices, we model the emissive layer as an effective medium using the dye's HOMO as hole transport level and the polymer LUMO as electron transport level. By fine-tuning the injection barriers at the electron and hole-injecting contact, respectively, in simulated devices, unipolarA comprehensive numerical device simulation of the electrical and optical characteristics accompanied with experimental measurements of a new highly efficient system for polymer-based light-emitting diodes doped with phosphorescent dyes is presented. The system under investigation comprises an electron transporter attached to a polymer backbone blended with an electronically inert small molecule and an iridium-based green phosphorescent dye which serves as both emitter and hole transporter. The device simulation combines an electrical and an optical model. Based on the known highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of all components as well as the measured electrical and optical characteristics of the devices, we model the emissive layer as an effective medium using the dye's HOMO as hole transport level and the polymer LUMO as electron transport level. By fine-tuning the injection barriers at the electron and hole-injecting contact, respectively, in simulated devices, unipolar device characteristics were fitted to the experimental data. Simulations using the so-obtained set of parameters yielded very good agreement to the measured currentvoltage, luminancevoltage characteristics, and the emission profile of entire bipolar light-emitting diodes, without additional fitting parameters. The simulation was used to gain insight into the physical processes and the mechanisms governing the efficiency of the organic light-emitting diode, including the position and extent of the recombination zone, carrier concentration profiles, and field distribution inside the device. The simulations show that the device is severely limited by hole injection, and that a reduction of the hole-injection barrier would improve the device efficiency by almost 50%.show moreshow less

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Metadaten
Author:Mahmoud Al-Sa'di, Frank Jaiser, Sergey Bagnich, Thomas Unger, James Blakesley, Andreas Wilke, Dieter NeherORCiDGND
DOI:https://doi.org/10.1002/polb.23158
ISSN:0887-6266 (print)
Parent Title (English):Journal of polymer science : B, Polymer physics
Publisher:Wiley-Blackwell
Place of publication:Hoboken
Document Type:Article
Language:English
Year of first Publication:2012
Year of Completion:2012
Release Date:2017/03/26
Tag:TCAD; conjugated polymers; high performance polymers; organic electronics; organic light-emitting diode; simulations
Volume:50
Issue:22
Pagenumber:10
First Page:1567
Last Page:1576
Funder:Bundesministerium fur Bildung und Forschung (BMBF) [FKZ 13N10622]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
Peer Review:Referiert