Phosphorescence from iridium complexes doped into polymer blends
Phosphorescence from iridium complexes doped into polymer blends
复制标题
DOI：
10.1063/1.1635976
复制
发表时间：
2004-02-01
影响因子：
3.2
通讯作者：
Bazan, GC
中科院分区：
文献类型：
--
作者：
Gong, X;Lim, SH;Bazan, GC
用稳态和时间分辨光致发光（PL）光谱研究了聚乙烯基咔唑（PVK）与2-叔丁基苯基-5-联苯-1，3，4-恶二唑（PBD）共混物与有机金属发光体三[9，9-二己基-2-（苯基-4（'）-（-吡啶-2（'）-基）芴]铱（III）[Ir（DPPF）（3）]之间的能量转移。在PVK-PBD共混物中形成了激基复合物，导致了PL的红移和缓慢的荧光衰减。随着Ir（DPPF）（3）浓度的增加，在425 nm处观察到的聚合物共混物中的强度降低，并且在200 ns时间尺度内在578至615 nm范围内在具有1 wt % Ir（DPPF）（3）的膜中观察到的明显上升特征表明发生了从激基复合物到Ir（DPPF）（3）的有效Forster能量转移。用掺杂有Ir（DPPF）（3）的PVK-PBD制备的电致磷光发光二极管在lwt % Ir（DPPF）（3）时具有8%ph/el的外量子效率、29 cd/A的发光效率和大于3500 cd/m2的亮度。即使在低浓度的Ir（DPPF）（3）（0.1wt%）下，器件也没有表现出来自PVK或PBD的电致发光（EL）发射，这表明EL中的主导机制是电荷捕获而不是能量转移。(C)2004年，美国物理学会。
Energy transfer from the polymer blends, poly(vinylcarbazole) (PVK) with 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazol (PBD), to an organometallic emitter, tris[9,9-dihexyl-2-(phenyl-4(')-(-pyridin-2(')-yl))fluorene] iridium (III) [Ir(DPPF)(3)], is investigated by steady-state and time-resolved photoluminescence (PL) spectroscopy. A redshifted PL and slow fluorescence decay are due to the formation of an exciplex in PVK-PBD blends. A decrease in intensity in polymer blends observed at 425 nm with increasing concentrations of Ir(DPPF)(3) and an evident rising feature observed in films with 1 wt % Ir(DPPF)(3) in the range of 578 to 615 nm within a 200 ns timescale indicate that efficient Forster energy transfer from exciplex to Ir(DPPF)(3) occurs. The electrophosphorescent light-emitting diodes fabricated with PVK-PBD doped with Ir(DPPF)(3) have external quantum efficiency of 8% ph/el, luminous efficiency of 29 cd/A and brightness greater than 3500 cd/m2 at 1 wt % Ir(DPPF)(3). The devices exhibited no electroluminescence (EL) emission from PVK or PBD even at a low concentration of Ir(DPPF)(3) (0.1 wt %), which indicates that the dominant mechanism in EL is charge trapping rather than energy transfer. (C) 2004 American Institute of Physics.