CHIH-I WUChang, J.-H.J.-H.ChangLiu, S.-Y.S.-Y.LiuWu, I.-W.I.-W.WuChen, T.-C.T.-C.ChenLiu, C.-W.C.-W.LiuCHIH-I WU2018-09-102018-09-102014http://www.scopus.com/inward/record.url?eid=2-s2.0-84898021093&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/387682The 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. © 2014 AIP Publishing LLC.[SDGs]SDG6journal article10.1063/1.4869183