Study of Host Materials for Phosphorescent Organic Light-emitting Devices
Date Issued
2005
Date
2005
Author(s)
Tsai, Hsin-Hung
DOI
en-US
Abstract
In this thesis, we demonstrated phosphorescent organic light-emitting devices (PHOLEDs) by using a novel host material and two transporting materials as the host of PHOLED. We used an n-type transporting material as the host of green PHOLED. Due to the better energy alignment with adjacent transporting materials, our device exhibits a lower turn-on voltage by about 2.5 volts with the current density of 100 mA/cm2 as compared to the conventional carbazole OLED. The power efficiency is increased from 8 to 10 lm/W at the luminance of 1000 cd/m2.However, the current efficiency at 10000 cd/m2 is slightly decreased from 24 to 21 cd/A.
Besides, we used two conventional transporting materials as the host of the red PHOLED and evaluate the necessity of the hole blocking layer (HBL) by using two Ir (iridium) based red emitter. Device with electron transporting material as the host with HBL structure exhibited the highest current efficiency of 16.1 cd/A at the luminance of 50 cd/m2. Besides, devices showed limited triplet-triplet annihilation.
Subjects
磷光
有機
phosphorescent
organic
Type
thesis
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