TY  - JOUR
A1  - Al-Sa'di, Mahmoud
A1  - Jaiser, Frank
A1  - Bagnich, Sergey A.
A1  - Unger, Thomas
A1  - Blakesley, James C.
A1  - Wilke, Andreas
A1  - Neher, Dieter
T1  - Electrical and optical simulations of a polymer-based phosphorescent organic light-emitting diode with high efficiency
T2  - Journal of polymer science : B, Polymer physics
N2  - 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, 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%.
KW  - conjugated polymers
KW  - high performance polymers
KW  - organic electronics
KW  - organic light-emitting diode
KW  - simulations
KW  - TCAD
Y1  - 2012
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/35520
SN  - 0887-6266
VL  - 50
IS  - 22
SP  - 1567
EP  - 1576
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -