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International Journal of Photoenergy
Volume 2013, Article ID 173289, 6 pages
http://dx.doi.org/10.1155/2013/173289
Research Article

Optimal Color Stability for White Organic Light-Emitting Diode (WOLED) by Using Multiple-Ultra-Thin Layers (MUTL)

1Department of Electronic Engineering, Fortune Institute of Technology, Kaohsiung 83160, Taiwan
2Department of Applied Physics, National University of Kaohsiung, Kaohsiung 81148, Taiwan
3Department of Electronic Engineering, National Formosa University, Hu-Wei, Yunlin 63201, Taiwan
4Department of Electro-Optical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan

Received 15 September 2013; Accepted 3 October 2013

Academic Editor: Liang-Wen Ji

Copyright © 2013 Kan-Lin Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The work demonstrates the improvement of color stability for white organic light-emitting diode (WOLED). The devices were prepared by vacuum deposition on ITO-glass substrates. These guest materials of 5,6,11,12-tetraphenylnaphthacene (Rubrene) were deposited in 4,4′-bis(2,2-diphenyl vinyl)-1,1′-biphenyl (DPVBi), resulting in an emitting layer. Experimental results reveal that the properties in the multiple-ultra-thin layer (MUTL) are better than those of the emitting layer with a single guest material, reaching the commercial white-light wavelength requirement of 400–700 nm. The function of the MUTL is as the light-emitting and trapping layer. The results show that the MUTL has excellent carrier capture effect, leading to high color stability of the device at various applied voltages. The Commissions Internationale De L’Eclairage (CIE) coordinate of this device at 3~7 V is few displacement and shows a very slight variation of (0.016, 0.009). The CIE coordinates at a maximal luminance of 9980 cd/m2 are (0.34, 0.33).