1. Stability improvement of organic light emitting diodes by the insertion of hole injection materials on the indium tin oxide substrate.
- Author
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Jung-Hung Chang, Shang-Yi Liu, I-Wen Wu, Tsung-Chin Chen, Chia-Wei Liu, and Chih-I Wu
- Subjects
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ORGANIC light emitting diodes , *INDIUM tin oxide , *SUBSTRATES (Materials science) , *DIFFUSION , *CHEMICAL reactions - Abstract
The degradation of organic light-emitting diodes (OLEDs) is a very complex issue, which might include interfacial charge accumulation, material diffusion, and electrical-induced chemical reaction during the operation. In this study, the origins of improvement in device stability from inserting a hole injection layer (HIL) at the indium tin oxide (ITO) anode are investigated. The results from aging single-layer devices show that leakage current increases in the case of ITO/hole transport layer contact, but this phenomenon can be prevented by inserting molybdenum oxide (MoO3) or 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN6) as an HIL. Moreover, X-ray photoemission spectroscopy suggests that the diffusion of indium atoms and active oxygen species can be impeded by introducing MoO3 or HAT-CN6 as an HIL. These results reveal that the degradation of OLEDs is related to indium and oxygen out-diffusion from the ITO substrates, and that the stability of OLEDs can be improved by impeding this diffusion with HILs. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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