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Title: Study on MoO{sub 3-x} films deposited by reactive sputtering for organic light-emitting diodes

Journal Article · · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films
DOI:https://doi.org/10.1116/1.3328822· OSTI ID:22051136
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  1. Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 229-8558 (Japan)

The authors investigate the role of reduced molybdenum trioxide [MoO{sub 3-x} (x{<=}1)] films in organic light-emitting diodes, particularly from the viewpoint of the oxidation state of Mo. MoO{sub 3-x} films were deposited by reactive sputtering under a mixture of argon (Ar) and oxygen (O{sub 2}). The O{sub 2} gas-flow ratio (GFR) [O{sub 2}/(Ar+O{sub 2})] was adjusted between 10% and 100%. Mo with six, five, and four valence electrons was detected in MoO{sub 3-x} film deposited with an O{sub 2} GFR of 10% and 12.5%, whereas, under higher O{sub 2} GFRs, only six valence electrons for Mo in the MoO{sub 3-x} film were detected. N,N{sup '}-di(1-naphthyl)-N,N{sup '}-diphenylbenzidine ({alpha}-NPD) layer, hole-transport material, were deposited over the MoO{sub 3-x} layer by subsequent vacuum evaporation. At the {alpha}-NPD/MoO{sub 3-x} interface, it was found that {alpha}-NPD cations were generated and that MoO{sub 3-x} was reduced, which provided evidence of charge transfer across the interface by Raman spectroscopy and x-ray photoelectron spectroscopy.

OSTI ID:
22051136
Journal Information:
Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 28, Issue 4; Other Information: (c) 2010 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
Country of Publication:
United States
Language:
English