Interfacial electronic structure of N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine/copper phthalocyanine:C60 composite/Au studied by ultraviolet photoemission spectroscopy

The interfacial electronic structures of N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB)/copper phthalocyanine (CuPc)∕Au, NPB∕C60∕Au, and NPB∕CuPc:C60 composite/Au were investigated by in situ ultraviolet photoelectron spectroscopy to understand the highly efficient hole injectio...

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Veröffentlicht in:Applied physics letters 2007-07, Vol.91 (5)
Hauptverfasser: Cho, Sang Wan, Yoo, Kyung-Hwa, Jeong, Kwangho, Whang, Chung-Nam, Yi, Yeonjin, Noh, Myungkeun
Format: Artikel
Sprache:eng
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Zusammenfassung:The interfacial electronic structures of N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB)/copper phthalocyanine (CuPc)∕Au, NPB∕C60∕Au, and NPB∕CuPc:C60 composite/Au were investigated by in situ ultraviolet photoelectron spectroscopy to understand the highly efficient hole injection in organic light-emitting diode. The hole-injection barrier of CuPc:C60∕Au was 0.52eV, while those of CuPc∕Au and C60∕Au were 0.96 and 1.62eV, respectively. The lowered injection barrier is attributed to the smaller interface dipole of CuPc:C60 compared to that of pristine CuPc. This small interface dipole pulled up the highest occupied molecular orbital of CuPc in composite, which results in the decreased hole-injection barrier.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.2761211