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Phenothiazine-phenylquinoline donor-acceptor molecules: Effects of structural isomerism on charge transfer photophysics and electroluminescence
被引:109
作者:
Kulkarni, AP
Wu, PT
Kwon, TW
Jenekhe, SA
[1
]
机构:
[1] Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA
[2] Univ Washington, Dept Chem, Seattle, WA 98195 USA
[3] Kyungsung Univ, Dept Chem, Pusan 608736, South Korea
[4] Kyungsung Univ, Ctr Organ Devices & Adv Mat, Pusan 608736, South Korea
关键词:
D O I:
10.1021/jp0529772
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
Large differences in the intramolecular charge-transfer fluorescence quantum yields and electroluminescence efficiencies were observed among the isomeric donor-acceptor molecules 2-(4-phenyl-2-quinolyl)-10-methylphenothiazine (2PQMPT) and 3-(4-phenyl-2-quinolyl)-10-methylphenothiazine (3PQMPT). In solution, the 2PQMPT isomer had a larger positive solvatochromism and thus a greater degree of charge transfer, whereas 3PQMPT had a larger fluorescence quantum yield (71%) compared to 2PQMPT (46%). High brightness (23750 cd/m(2)) and high efficiency (8.18 cd/A, 4.45 lm/W, 2.42% external quantum efficiency at 1015 cd/m(2)) green electroluminescence was achieved from 3PQMPT diodes. In contrast, green light-emitting diodes with lower brightness (8900 cd/m(2)) and efficiencies (4.79 cd/A, 2.36 lm/W, 1.41% external quantum efficiency at 690 cd/m(2)) were obtained from 2PQMPT. The two isomeric donor-acceptor molecules had identical HOMO (5.1 eV) and LUMO (2.4 eV) energy levels derived from electrochemistry. Density functional theory (DFT) calculations provided insights into the molecular geometry, electronic structures, and properties of the donor-acceptor isomers. These results demonstrate the pronounced influence of the donor/acceptor connection on the charge-transfer emission efficiency of donor-acceptor molecules and the performance of solid-state light-emitting devices based on them.
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页码:19584 / 19594
页数:11
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