CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Cathode Formed by Thermal Evaporation of Ba:Al Alloy and Estimations of Barrier Height in an Organic LED |
DING Lei1**, ZHANG Fang-Hui1,2
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1School of Electrical and Information Engineering, Shaanxi University of Science and Technology, Xi'an 710021
2Shaanxi Panel Display Engineering Center, Xi'an 710021
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Cite this article: |
DING Lei, ZHANG Fang-Hui 2011 Chin. Phys. Lett. 28 067801 |
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Abstract It is demonstrated that barium and aluminum alloy synthesized by melting in a glass tube under low vacuum is applicable for organic laser emitting diodes (LEDs) as a thin film cathode. The alloy film obtained by the thermal evaporation of pre-synthesized alloy is used in a single-boat organic LED device with the structure: indium tin oxide (ITO)/4,4'-bis[N−(1-naphthyl)-N−phenylamino]biphenyl(NPB)/tris-(8-hydroxyquinoline) aluminum(Alq3)/barium:aluminum alloy. The experimental results show that devices with this alloy film cathode exhibit better current density-voltage-luminance characteristics than those with a conventional pure Al cathode, and more weight of barium in aluminum leads to better performance of the devices. Characteristics of current density versus voltage for the electron-only devices are fitted by the Richardson–Schottky emission model, indicating that the electron injection barrier has a decrease of about 0.3 eV by this alloy cathode.
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Keywords:
78.30.Fs
78.30.Jw
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Received: 12 April 2011
Published: 29 May 2011
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PACS: |
78.30.Fs
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(III-V and II-VI semiconductors)
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78.30.Jw
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(Organic compounds, polymers)
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