The origin of the hole injection improvements at indium tin oxide/molybdenum trioxide/N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl- 4,4′-diamine interfaces
2008; American Institute of Physics; Volume: 93; Issue: 4 Linguagem: Inglês
10.1063/1.2965120
ISSN1520-8842
AutoresHyunbok Lee, Sang Wan Cho, Kyul Han, Pyung Eun Jeon, Chung-Nam Whang, Kwangho Jeong, Kwanghee Cho, Yeonjin Yi,
Tópico(s)Organic Electronics and Photovoltaics
ResumoWe investigated the interfacial electronic structures of indium tin oxide (ITO)/molybdenum trioxide (MoO3)/N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) using in situ ultraviolet and x-ray photoemission spectroscopy to understand the origin of hole injection improvements in organic light-emitting devices (OLEDs). Inserting a MoO3 layer between ITO and NPB, the hole injection barrier was remarkably reduced. Moreover, a gap state in the band gap of NPB was found which assisted the Ohmic hole injection at the interface. The hole injection barrier lowering and Ohmic injection explain why the OLED in combination with MoO3 showed improved performance.
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