This work was supported by the NSFC (Nos. 50633050, 20721061, 50503020, and 20773156).
Binaphthyl-Containing Green- and Red-Emitting Molecules for Solution-Processable Organic Light-Emitting Diodes†
Article first published online: 22 OCT 2008
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 18, Issue 20, pages 3299–3306, October 23, 2008
How to Cite
Zhou, Y., He, Q., Yang, Y., Zhong, H., He, C., Sang, G., Liu, W., Yang, C., Bai, F. and Li, Y. (2008), Binaphthyl-Containing Green- and Red-Emitting Molecules for Solution-Processable Organic Light-Emitting Diodes. Adv. Funct. Mater., 18: 3299–3306. doi: 10.1002/adfm.200800375
- Issue published online: 22 OCT 2008
- Article first published online: 22 OCT 2008
- Manuscript Revised: 17 JUN 2008
- Manuscript Received: 16 MAR 2008
- amorphous materials;
- organic light-emitting diodes;
- solution processing
Strong intermolecular interactions usually result in decreases in solubility and fluorescence efficiency of organic molecules. Therefore, amorphous materials are highly pursued when designing solution-processable, electroluminescent organic molecules. In this paper, a non-planar binaphthyl moiety is presented as a way of reducing intermolecular interactions and four binaphthyl-containing molecules (BNCMs): green-emitting BBB and TBT as well as red-emitting BTBTB and TBBBT, are designed and synthesized. The photophysical and electrochemical properties of the molecules are systematically investigated and it is found that TBT, TBBBT, and BTBTB solutions show high photoluminescence (PL) quantum efficiencies of 0.41, 0.54, and 0.48, respectively. Based on the good solubility and amorphous film-forming ability of the synthesized BNCMs, double-layer structured organic light-emitting diodes (OLEDs) with BNCMs as emitting layer and poly(N-vinylcarbazole) (PVK) or a blend of poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] and PVK as hole-transporting layer are fabricated by a simple solution spin-coating procedure. Amongst those, the BTBTB based OLED, for example, reaches a high maximum luminance of 8315 cd · m−2 and a maximum luminous efficiency of 1.95 cd · A−1 at a low turn-on voltage of 2.2 V. This is one of the best performances of a spin-coated OLED reported so far. In addition, by doping the green and red BNCMs into a blue-emitting host material poly(9,9-dioctylfluorene-2,7-diyl) high performance white light-emitting diodes with pure white light emission and a maximum luminance of 4000 cd · m−2 are realized.