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有机电致磷光掺杂和主体材料的合成及性能研究

Synthesis and Properties Characterization of Phosphorescent Dopants and Host Materials in Phosphorescent Organic Light-Emitting Devices

【作者】 何鉴

【导师】 张晓宏;

【作者基本信息】 中国科学院研究生院(理化技术研究所) , 有机化学, 2007, 博士

【摘要】 本论文设计并合成了一系列具有高三重态能级的咔唑衍生物类主体材料和以苯基蒎烯吡啶为配体的铱配合物磷光掺杂材料,对它们的光物理性质及能级结构进行了较详细的研究。具体研究成果如下:1.设计并合成了一组咔唑衍生物类主体材料。它们的三重态能级比CBP提高了0.1-0.3eV,高于一般蓝光磷光材料,是可应用于蓝光磷光器件的主体材料。以CPBCH和CBPE为主体材料的蓝光PHOLED器件结果表明,这些化合物是与CBP相当或性能更好的蓝光主体材料。2.设计并合成了一组带烷氧基团的苯基蒎烯吡啶铱(III)配合物Ir(RO-pppy)3。光物理性质研究表明,分子中带有的一定长度的直链可以减弱分子间的相互作用。掺杂于聚合物的器件结果表明,带有16碳烷氧基链的铱(Ⅲ)配合物表现出更好的器件行为,优化器件的掺杂浓度达到3.2 wt.-%,器件的最高发光效率为19.9 cd/A (7.8 lm/W,9.1V) ,得到的器件最大亮度为15700 cd/m2 ( 8.4V)。3.设计并合成了一组带苯基蒎烯吡啶配体的双环铱(III)配合物FpIrpic,FpIr(acac)和FpIrN4。它们的最高发射峰分别在469nm,479nm和460nm;量子产率依次为0.68,0.52和0.064,是一类新型的蓝光磷光掺杂材料。4.设计并合成了两个同时带有电子传输性能(噁二唑基团)和空穴传输性能(咔唑基团)的化合物C1PBD和C5PBD。研究结果表明,它们的HOMO、LUMO能级结构与我们设计合成的新型蓝光/绿光铱(III)配合物匹配,它们的三重态能级达到2.68eV,是可用于蓝光/绿光磷光器件的主体材料。5.以合成的5个主体材料及蓝光磷光材料FIrpic为研究对象(CBP作为对比),对其构建的主体-客体体系能量转移机制进行了研究。结果表明,在相同条件下,CBP和o-CBP具有相对较低的能量转移效率。通过激发光谱的研究证明能量转移的存在;通过发光衰减曲线表明了CBP与FIrpic之间存在着三重态能量回传,这可能是其能量转移效率偏低的原因。

【Abstract】 The thesis mainly described the design and synthesis of a series of carbazole derivatives with high triplet energy as host materials and a series of Ir-complex featuring pinene-2-phenylpyridine ligands as phosphorescent dopants in Phosphorescent Organic Light-Emitting Devices (PHOLED). Their photophysical properties and energy level structures were intensively investigated.The main results of the thesis are summarized as follows:(1) A new series of carbazole derivatives as host materials have been designed and synthesized. Their triplet energy is 0.1-0.3eV higher than that of CBP, and the other typical blue phosphorescent dopants. They can be employed in blue PHOLED as host materials. The results of PHOLED fabricated using these derivatives as the host materials indicated that the properties of them are equal to or better than those of CBP.(2) The new series of Ir-complexes(Ir(RO-pppy)3)featuring pinene group and various alkoxy side chains have been designed and synthesized. The results of the photophysical properties indicated that the complex with long side chains could reduce the interaction between molecules. The Ir(C16H33O-pppy)3-based devices exhibit better EL performance, the maximum luminance efficiency, 19.9 cd/A (7.8 lm/W) at 9.1V, was obtained with doping concentration of 3.4wt.-%, and the maximum luminance of the devices was 15700 cd/m2 at 8.4V.(3) A new family of cyclometalated Ir-complexes, FpIrpic, FpIr(acac) and FpIrN4 ,featuring 2-phenyl-pinenepyridine ligands have been synthesized. Their main emitting peaks are located at 469nm, 479nm and 460nm, respectively. Their phosphorescence quantum yields were 0.68, 0.52 and 0.064, respectively. The results indicated that they are novel blue phosphorescent dopants. (4) Two host materials, C1PBD and C5PBD, with ambipolar carrier transport properties have been synthesized and investigated. The results indicated that their HOMO and LUMO energy levels match well with those of blue/green Ir-complex dopants developed by us. Their triplet energy is 2.68eV, which indicates that they can be employed as blue/green host materials in PHOLED.(5) The energy transfer mechanism of host-guest system composed of each of 5 the novel blue host materials (using CBP as a reference) and FIrpic have been investigated. The results indicated that there were relatively poor energy transfer efficiencies between CBP or o-CBP and FIrpic. The results of the excitation spectroscopy proved the existence of the energy transfer in the system. Transit photoluminescence decays indicated the triplet-triplet energy transfer from FIrpic back to CBP, which is the possible reason for the poor energy transfer efficiency.

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