Temperature dependence of electroluminescence degradation in organic light emitting devices without and with a copper phthalocyanine buffer layer
✍ Scribed by Paulo N.M dos Anjos; Hany Aziz; Nan-Xing Hu; Zoran D Popovic
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 103 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1566-1199
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✦ Synopsis
Temperature dependence of electroluminescence degradation was investigated in two types of organic light emitting devices (OLEDs) based on tris(8-hydroxyquinoline) aluminum (AlQ 3 ) emitter molecule, one without and another with copper phthalocyanine (CuPc) buffer layer at the hole-injecting contact interface. Electroluminescence degradation in time was measured for devices operated at 22 and 70 °C. Results unexpectedly showed that devices without the CuPc buffer layer demonstrated negligible change in half-life when operated at 22 or 70 °C, while devices with the CuPc layer showed the expected decrease in half-life when the temperature was increased. The results are explained within the framework of recently proposed OLED degradation mechanism, which identifies AlQ 3 cations as unstable, leading to device degradation.