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Proceedings Paper

Molecular orientation, thermal behavior and density of electron and hole transport layers and the implication on device performance for OLEDs
Author(s): Kenneth L. Kearns; Hong-Yeop Na; Robert D. Froese; Sukrit Mukhopadhyay; Hunter Woodward; Dean Welsh; Timothy De Vries; David Devore; Peter Trefonas; Liang Hong
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Paper Abstract

Recent progress has shown that molecular orientation in vapor-deposited glasses can affect device performance. The deposition process can result in films where the molecular axis of the glass material is preferentially ordered to lie parallel to the plane of the substrate. Here, materials made within Dow’s Electronic Materials business showed enhanced performance when the orientation of the molecules, as measured by variable angle spectroscopic ellipsometry, was oriented in a more parallel fashion as compared to other materials. For one material, the anisotropic packing was observed in the as-deposited glass and was isotropic for solution-cast and annealed films. In addition, the density of an as-deposited N,N′-bis(naphthalene-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine (NPD) film was 0.8% greater than what was realized from slowly cooling the supercooled liquid. This enhanced density indicated that vapor-deposited molecules were packing more closely in addition to being anisotropic. Finally, upon heating the NPD film into the supercooled liquid state, both the density and anisotropic packing of the as-deposited glass was lost.

Paper Details

Date Published: 8 October 2014
PDF: 12 pages
Proc. SPIE 9183, Organic Light Emitting Materials and Devices XVIII, 91830F (8 October 2014); doi: 10.1117/12.2062991
Show Author Affiliations
Kenneth L. Kearns, The Dow Chemical Co. (United States)
Hong-Yeop Na, The Dow Seoul Technology Ctr. (Korea, Republic of)
Robert D. Froese, The Dow Chemical Co. (United States)
Sukrit Mukhopadhyay, The Dow Chemical Co. (United States)
Hunter Woodward, The Dow Chemical Co. (United States)
Dean Welsh, The Dow Chemical Co. (United States)
Timothy De Vries, The Dow Chemical Co. (United States)
David Devore, The Dow Chemical Co. (United States)
Peter Trefonas, Dow Electronic Materials (United States)
Liang Hong, Dow Elastomers, Electrical and Telecommunications (United States)

Published in SPIE Proceedings Vol. 9183:
Organic Light Emitting Materials and Devices XVIII
Franky So; Chihaya Adachi, Editor(s)

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