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Document Type |
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Article In Journal |
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Document Title |
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Theoretical investigation of triscarbazole derivatives as host materials for blue electrophosphorescence: Effects of topology Theoretical investigation of triscarbazole derivatives as host materials for blue electrophosphorescence: Effects of topology |
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Subject |
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Chemistry |
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Document Language |
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English |
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Abstract |
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We have investigated the electronic structure of triscarbazole derivatives used as host materials in blue phosphorescent organic light-emitting diodes. The results of density functional theory calculations show that, in the case of triscarbazole derivatives where the carbazole units are linked via C-C bonds, the frontier molecular orbital energies are modulated by strong molecular orbital interactions between the central and side carbazole units. On the other hand, in the case of triscarbazoles linked via C-N bonds, the combination of inductive effects and molecular orbital interactions tunes the frontier level energies and, interestingly, gives rise to an ambipolar character. In the C-N linked systems, the lowest triplet states are characterized mainly by an electronic transition localized within the central carbazole, while in the C-C linked compounds it is the longest oligo-para-phenyl segment to be found in the chemical structure that defines the lowest triplet transition. When the N-H group of the central carbazole unit is replaced by other groups [O, S, CH 2, C(CH3)2, C(CH3)(CF3), and C(CF3)2], the HOMO/LUMO energies fluctuate substantially in the absence of the side carbazoles, but these variations are significantly reduced in their presence; also, the singlet-triplet energy differences decrease substantially when going from the isolated central unit to the triscarbazole-like derivatives. |
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ISSN |
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0897-4756 |
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Journal Name |
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Chemistry of Materials |
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Volume |
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23 |
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Issue Number |
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23 |
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Publishing Year |
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1432 AH
2011 AD |
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Article Type |
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Article |
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Added Date |
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Sunday, March 11, 2012 |
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Researchers
| Seyhan Salman | Salman, Seyhan | Researcher | Doctorate | |
| DongWook Kim | Kim, DongWook | Researcher | Doctorate | dongwook-kim@kyonggi.ac.kr |
| Veaceslav P Coropceanu | Coropceanu, Veaceslav P | Researcher | Doctorate | |
| Jean Luc Brédas | Brédas, Jean Luc | Researcher | Doctorate | jean-luc.bredas@chemistry.gatech.edu |
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