High-performance organic light-emitting diodes based on intramolecular charge-transfer emission from donor-acceptor molecules: Significance of electron-donor strength and molecular geometry

被引:158
作者
Kulkarni, Abhishek P.
Kong, Xiangxing
Jenekhe, Samson A. [1 ]
机构
[1] Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA
[2] Univ Washington, Dept Chem, Seattle, WA 98195 USA
关键词
D O I
10.1002/adfm.200500722
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Organic light-emitting diodes based on intramolecular-charge-transfer emission from two related donor-acceptor (D-A) molecules, 3,7-[bis(4-phenyl-2-quinolyl)]-10-methylphenothiazine (BPQ-MPT) and 3,6-[bis(4-phenyl-2-quinolyl)]-9-methylcarbazole (BPQ-MCZ), were found to have electroluminescence (EL) efficiencies and device brightnesses that differ by orders of magnitude. High brightness (> 40 000 cd m(-2)) and high efficiency (21.9 cd A(-1), 10.8 lm W-1, 5.78 % external quantum efficiency (EQE) at 1140 cd m(-2)) green EL was achieved from the BPQ-MPT emitter, which has its highest occupied molecular orbital (HOMO) level at 5.09 eV and a nonplanar geometry. In contrast, diodes with much lower brightness (2290 cd m-2) and efficiency (1.4 cd A(-1), 0.66 Im W-1, 1.7 % EQE at 405 cd m(-2)) were obtained from the BPQ-MCZ emitter, which has its HOMO level at 5.75 eV and exhibits a planar geometry. Compared to BPQ-MCZ, the higher-lying HOMO level of BPQ-MPT facilitates more efficient hole injection/transport and a higher charge-recombination rate, while its nonplanar geometry ensures diode color purity. White EL was observed from BPQ-MCZ diodes owing to a blue intramolecular charge-transfer emission and a yellow-orange intermolecular excimer emission, enabled by the planar molecular geometry. These results demonstrate that high-performance light-emitting devices can be achieved from intramolecular charge-transfer emission, while highlighting the critical roles of the electron-donor strength and the molecular geometry of D-A molecules.
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收藏
页码:1057 / 1066
页数:10
相关论文
共 80 条
[1]   Electrochemical properties and electronic structures of conjugated polyquinolines and polyanthrazolines [J].
Agrawal, AK ;
Jenekhe, SA .
CHEMISTRY OF MATERIALS, 1996, 8 (02) :579-589
[2]   ELECTROCHEMICAL AND SPECTROSCOPIC PROPERTIES OF CATION RADICALS .3. REACTION PATHWAYS OF CARBAZOLIUM RADICAL IONS [J].
AMBROSE, JF ;
CARPENTER, LL ;
NELSON, RF .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1975, 122 (07) :876-894
[3]   Electrochemistry and electrogenerated chemiluminescence processes of the components of aluminum quinolate/triarylamine, and related organic light-emitting diodes [J].
Anderson, JD ;
McDonald, EM ;
Lee, PA ;
Anderson, ML ;
Ritchie, EL ;
Hall, HK ;
Hopkins, T ;
Mash, EA ;
Wang, J ;
Padias, A ;
Thayumanavan, S ;
Barlow, S ;
Marder, SR ;
Jabbour, GE ;
Shaheen, S ;
Kippelen, B ;
Peyghambarian, N ;
Wightman, RM ;
Armstrong, NR .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1998, 120 (37) :9646-9655
[4]   Blue-green organic light-emitting diodes based on fluorene-oxadiazole compounds [J].
Antoniadis, H ;
Inbasekaran, M ;
Woo, EP .
APPLIED PHYSICS LETTERS, 1998, 73 (21) :3055-3057
[5]   Light-emitting electrochemical processes [J].
Armstrong, NR ;
Wightman, RM ;
Gross, EM .
ANNUAL REVIEW OF PHYSICAL CHEMISTRY, 2001, 52 :391-422
[6]   ELECTRON-DONATING PROPERTIES OF PHENOTHIAZINE AND RELATED COMPOUNDS [J].
BLOOR, JE ;
GILSON, BR ;
HAAS, RJ ;
ZIRKLE, CL .
JOURNAL OF MEDICINAL CHEMISTRY, 1970, 13 (05) :922-&
[7]   Oxidation of carbazole, N-ethylcarbazole, fluorene, and dibenzothiophene by the laccase of Coriolopsis gallica [J].
Bressler, DC ;
Fedorak, PM ;
Pickard, MA .
BIOTECHNOLOGY LETTERS, 2000, 22 (14) :1119-1125
[8]  
Brown J., 2004, Journal of the Society for Information Display, V12, P329, DOI 10.1889/1.1821306
[9]   Carbazole compounds as host materials for triplet emitters in organic light-emitting diodes:: Tuning the HOMO level without influencing the triplet energy in small molecules [J].
Brunner, K ;
van Dijken, A ;
Börner, H ;
Bastiaansen, JJAM ;
Kiggen, NMM ;
Langeveld, BMW .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2004, 126 (19) :6035-6042
[10]   Efficient green organic light-emitting diodes with stericly hindered coumarin dopants [J].
Chen, CH ;
Tang, CW .
APPLIED PHYSICS LETTERS, 2001, 79 (22) :3711-3713