Sato Shuri, Takata Masashi, Takada Makoto, Naito Hiroyoshi
J Nanosci Nanotechnol. 2016 Apr;16(4):3368-72. doi: 10.1166/jnn.2016.12306.
The degradation of bilayer organic light-emitting diodes (OLEDs) with a device structure of N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (α-NPD) (hole transport layer) and tris-(8-hydroxyquinolate)aluminum (Alq3) (emissive layer and electron transport layer) has been studied by impedance spectroscopy and device simulation. Two modulus peaks are found in the modulus spectra of the OLEDs below the electroluminescence threshold. After aging of the OLEDs, the intensity of electroluminescence is degraded and the modulus peak due to the Alq3 layer is shifted to lower frequency, indicating that the resistance of the Alq3 layer is increased. Device simulation reveals that the increase in the resistance of the Alq3 layer is due to the decrease in the electron mobility in the Alq3 layer.
采用阻抗谱和器件模拟研究了具有N，N'-二（1-萘基）-N，N'-二苯基联苯胺（α-NPD）（空穴传输层）和三（8-羟基喹啉）铝（Alq3）（发光层和电子传输层）器件结构的双层有机发光二极管（OLED）的退化情况。在低于电致发光阈值的OLED模量谱中发现了两个模量峰。OLED老化后，电致发光强度降低，并且由于Alq3层导致的模量峰向低频移动，这表明Alq3层的电阻增加。器件模拟表明，Alq3层电阻的增加是由于Alq3层中电子迁移率的降低。
