Anomalous hole injection deterioration of organic light-emitting diodes with a manganese phthalocyanine layer
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
- Institute of Physics and Applied Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of)
- Department of Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 220-710 (Korea, Republic of)
- Korea Research Institute of Standards and Science, 267 Gajeong-ro, Daejeon 305-340 (Korea, Republic of)
Metal phthalocyanines (MPcs) are well known as an efficient hole injection layer (HIL) in organic devices. They possess a low ionization energy, and so the low-lying highest occupied molecular orbital (HOMO) gives a small hole injection barrier from an anode in organic light-emitting diodes. However, in this study, we show that the hole injection characteristics of MPc are not only determined by the HOMO position but also significantly affected by the wave function distribution of the HOMO. We show that even with the HOMO level of a manganese phthalocyanine (MnPc) HIL located between the Fermi level of an indium tin oxide anode and the HOMO level of a N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine hole transport layer the device performance with the MnPc HIL is rather deteriorated. This anomalous hole injection deterioration is due to the contracted HOMO wave function, which leads to small intermolecular electronic coupling. The origin of this contraction is the significant contribution of the Mn d-orbital to the MnPc HOMO.
- OSTI ID:
- 22412976
- Journal Information:
- Journal of Applied Physics, Vol. 117, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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