http://repository.iitr.ac.in/handle/123456789/3395
Title: | Green and yellow electroluminescent dipolar carbazole derivatives: Features and benefits of electron-withdrawing segments |
Authors: | Justin Thomas, K. R. Lin J.T. Tao Y.-T. Chuen C.-H. |
Published in: | Chemistry of Materials |
Abstract: | New multiply substituted carbazole derivatives containing fluorene or phenylene conjugated oxadiazole segments and quinoxaline units were obtained by palladium-catalyzed C-N coupling reactions. They are amorphous with the glass transition temperature (Tg) in the range 104-176°C. The emission color of the materials varies from blue to yellow and is dependent on the nature of the electron-withdrawing segments and solvents. Two reversible one-electron oxidations were observed for these molecules in cyclic voltammograms, which originate from the peripheral 3,6-diarylamino units in the 3,6,9-trisubstituted derivatives and diarylamine and carbazole segments in the 3,9-disubstituted compounds. Reductions originating from quinoxaline segments were also located for the molecules incorporating quinoxaline moieties. The double-layer organic light-emitting diodes fabricated using these compounds as hole-transporting/emitting layers and TPBI or Alq3 as an electron-transporting layer emit bluish green to yellow colors. The recombination zone is restricted in the HTL layer for the quinoxaline-containing molecules irrespective of the electron-transporting layer used and emission occurs from them. However, for the oxadiazole derivatives emission in the Alq3-based devices is either red-shifted or resembles that of Alq3-Cyclic voltammetric and spectroscopic data support more pronounced electron affinity for the quinoxaline-incorporated carbazole derivatives than for the oxadiazole-tethered carbazole materials. |
Citation: | Chemistry of Materials (2002), 14(9): 3852-3859 |
URI: | https://doi.org/10.1021/cm0202512 http://repository.iitr.ac.in/handle/123456789/3395 |
Issue Date: | 2002 |
ISSN: | 8974756 |
Author Scopus IDs: | 57203389297 7501725859 7402420315 6701637461 |
Author Affiliations: | Thomas, K.R.J., Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan Lin, J.T., Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan, Department of Chemistry, National Central University, 320 Chungli, Taiwan Tao, Y.-T., Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan Chuen, C.-H., Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan |
Corresponding Author: | Lin, J.T.; Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan; email: jtlin@chem.sinica.edu.tw |
Appears in Collections: | Journal Publications [CY] |
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