吡啶-芴类电荧光聚合物的光谱特性

用Suzuiki聚合反应将二溴代吡啶 (2 ,5 、2 ,6 、3,5 取代 )与芴共聚 ,合成了不同主链结构的吡啶 芴共聚物 .研究结果表明 ,将吡啶基引人聚芴主链可以调节共聚物的发光颜色 .间位吡啶基引入聚芴主链 ,使聚合物的能级加宽 ,PL、EL光谱发生蓝移 ;对位吡啶基则使光谱红移 .间位吡啶基 (3,5 Py、2 ,6 Py)引入聚芴主链 ,可提高聚合物的色纯度 .共聚物中 3,5 Py含量为 4 0mol%时 ,可得到较纯的蓝光 .     

Green-Yellow Electrophosphorescence from di [2,5-diphenyl- 1,3,4-oxadiazole C2′ , N^3] Platinum（Ⅱ） Doped PVK Devices

Employing a blend of poly (N-vinylcarbazole) (PVK) and 5-biphenyl-2-(4-tert-butyl)phenyl-1,3,4-oxadiazole) (PBD) as host matrix and a novel bicyclometalated Pt-complex containing 1,3,4-oxadiazole moiety as guest matrix with 2 wt. % doping concentration, we have demonstrated efficient phosphorescence-based polymer lightemitting devices (PLEDs). The devices emitted intense green yellow electrophosphorescence. No emission from either PVK or PBD was observed for the devices. The electroluminescence spectrum exhibited three primary peaks at 525nm, 568nm and 608nm. A maximum external quantum efficiency of 2.3% ph/el and a luminous efficiency of 3.Scd/A were achieved at a current density of 3.4mA/cm^2. The results demonstrate that highly efficient electrophosphorescence can be achieved from platinum complex-based polymer light-emitting devices.     

芴-噁二唑类聚合物的合成及光谱特性

通过缩聚反应,制得了高分子量的线型和超支化的芴-噁二唑类聚合物．它们均可溶于常用的有机溶剂。在固态薄膜时,它们的紫外-可见光吸收光谱在大约398nm和376nm处有两个强的吸收峰。它们的薄膜PL光谱在蓝光波长范围内有强发射峰,薄膜PL效率约为16％。电化学测试显示它们的的LUMO能级比芴的均聚物高,而与钙、镁这样典型的阴极材料的功函数较接近．这表明此类聚合物具有较好的电子注入和传输性能。     

芴-alt-咔唑类电磷光共聚物的发光性能

用共聚合方法将金属配合物引入共轭大分子链,使配合物之间的相互作用减少,有利于磷光体的均匀分散,增加在聚合物基体中的稳定性。将配合物引入共轭聚合物主链,在发光过程中主体链段既能将能量传递到客体,同时和配合物相邻的主体单元又能与配合物形成新的配体结构。共聚单元与配合物配体连接点的位置和键角的不同,影响聚合物的发光波长和发光效率。本文利用苯基异喹啉苯环上间位的溴将二(苯基异喹啉)乙酰丙酮合铱,通过Suzuki缩聚反应引入芴-咔唑交替共聚物主链,得到一种新型电磷光红光聚合物。聚合物器件的EL光谱发光波长为623nm,最大外量子效率为2.8%。     

三苯胺-芴类共聚物的合成及发光性能

在主链上嵌入三苯胺基团来改善聚芴的空穴传输能力、平衡载流子的注入是目前改善聚芴材料发光效率的一种好方法。本文用Suzuki缩聚法合成了芴-三苯胺类共聚物。实验结果表明．在聚芴主链上引入少量的TPA(10％～20％)时．不仅提高了EL效率．而且可以改善光谱的色纯度。TPA含量为20％时,共聚物的EL效率为1．28％。     

Highly Efficient Electrophosphorescence from a Grafted Biscyclometalated Iridium Complex with Triarylamine Unit in Polymer Light-Emitting Devices

The electroluminescence performance from a novel grafted cyclometalated iridium complex (BuPhNPPy)2Ir(acac)with triarylmine unit, where BuPhNPPy is N,N-di(4-tert-butylphenyl)-4-(2-pyridyl) phenylamine and Hacac is acetylacetone, is demonstrated in the double-layered polymer light-emitting devices (PLEDs). The PLEDs emit intense green phosphorescence at 533 nm with a shoulder peak of 566 nm employing 4 wt. % (BuPhNPPy)2Ir(acac)doped a blend of poly(vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-l,3,4-oxadiazole (PBD) as the emitting layer. A maximum luminance of 14610cd/m^2 at voltage of 24 V and a maximum external quantum efficiency Eext of 10.4% photons per electron (ph/el) at current density of 32mA/cm^2 are achieved. When the current density is raised to 100mA/cm^2, Eext of the device still remained to 8.3% ph/el. This indicates that the triplet-triplet annihilation is restrained more effectively at high current density. The improvement of electrophosphorescence performances of the iridium complex may be contributed to an ortho-substituent effect of grafted triarylmine unit.     

高效磷光聚合物发光二极管的实现

在有机及聚合物电致发光器件中 ,三重态发光 (磷光 )可以获得较高的量子效率 ,已在有机发光二极管平板显示中得到了广泛的应用。从能量传输的角度分析了提高磷光聚合物发光二极管器件发光效率的主要方法 ,综述了高效磷光聚合物发光二极管的实现途径与进展。