Energy level alignment in N

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• 作者：Sang Wan Cho ; Yeonjin Yi ; Myungkeun Noh ; Mann-Ho Cho ; Kyung-Hwa Yoo ; Kwangho Jeong ; Chung-Nam Whang
• 关键词：NPB ; CuPc ; F₁₆CuPc ; Photoemission ; Interface dipole ; Band diagram
• 刊名：Synthetic Metals
• 出版年：2008
• 出版时间：August 2008
• 年：2008
• 卷：158
• 期：13
• 页码：539-543
• 全文大小：837 K

文摘

The interfacial electronic structures of N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB)/hexadecafluoro copper phthalocyanine (F₁₆CuPc)/Au and NPB/copper phthalocyanine (CuPc)/Au were investigated by in situ X-ray and ultraviolet photoelectron spectroscopy to study the hole-injection barrier depending on the ionization energy of hole-injection layer materials. Although the measured ionization energy of F₁₆CuPc (6.30 eV) was much higher than that of CuPc (5.15 eV), the difference in the barrier heights of the two different films was relatively marginal (0.27 eV) due to the formation of interface dipole caused by the charge redistribution. We confirmed that the interface dipole of the buffer layer (CuPc and F₁₆CuPc) pushed down the core levels as well as the valence levels of the top organic layer (NPB) in the NPB/F₁₆CuPc/Au and NPB/CuPc/Au heterojunction.