【作者】 何磊；

【导师】 邱勇；

【作者基本信息】 清华大学 ， 化学， 2011， 博士

【摘要】 基于离子型铱配合物的发光电化学池（light-emitting electrochemical cells,LECs）和有机发光二极管（organic light-emitting diodes, OLEDs）可以用作新型显示或固态照明器件。针对目前离子型铱配合物应用到LEC和OLED中的研究发展状况，本论文设计和合成了新型离子型铱配合物，特别是蓝光离子型铱配合物，研究了配合物的光物理和电化学等性质及其在LEC和OLED中的发光性质。传统的离子型铱配合物使用联吡啶（2,2’-bipyridine, bpy）类第二配体，很难实现色纯度优异的蓝光发射。本论文提出了一种新的获得蓝光离子型铱配合物的分子设计思想：在第二配体环中插入给电子原子，提升配合物的最低未占有分子轨道（lowest unoccupied molecular orbital, LUMO）的能级。设计并成功合成了含吡唑类第二配体的新型蓝绿光和蓝光配合物。相比于经典的bpy类第二配体，吡唑类第二配体使配合物的LUMO能级升高0.27-0.31eV，发光波长蓝移100多个nm。制备的蓝光LEC的发光波长位于460nm，色坐标为（0.20,0.28），发光色纯度显著优于文献报道的其它基于离子型铱配合物的蓝光LEC。设计合成了含咪唑类第二配体的离子型铱配合物。咪唑类第二配体也显著蓝移配合物的发光。通过调控咪唑类第二配体的共轭度，获得了从蓝绿光到红光发射的新型离子型铱配合物体系。制备了蓝绿光、绿光、黄光和橙红光LEC器件，最大电流效率分别达到8.4、18.6、12.7和13.2cd/A。由于在配合物分子内引入了枝状位阻基团，蓝绿光LEC的最大电流效率提高到了18.3cd/A，是目前报道效率最高的蓝绿光LEC。通过在蓝绿光LEC中掺杂少量的红光配合物，白光LEC的发光色坐标为（0.37,0.41），颜色指数为80，最大电流效率、外量子效率和功率效率分别达到11.4cd/A、5.6%和11.2lm/W，是目前报道效率最高的白光LEC。本论文还系统研究了离子型铱配合物作为磷光染料在湿法制备的OLED中的发光性能。蓝绿光、绿光、黄光和红光OLED的最大电流效率分别达到24.3、25.3、20.5和4.2cd/A。制备了基于离子型铱配合物的白光OLED，最大电流效率、外量子效率和功率效率分别达到20.7cd/A、9.6%和8.5lm/W。更多还原

【Abstract】 Light-emitting electrochemical cells (LECs) and organic light-emitting diodes(OLEDs) based on ionic iridium complexes can be used as new-type displays or lightingsources. On the basis of the research progress of ionic iridium complexes in LECs andOLEDs, the paper focuses mainly on the development of novel ionic iridium complexes,especially those blue-emitting ones, explores the photophysical and electrochemicalproperties of the complexes and the performances of the complexes in LECs andOLEDs.Conventional ionic iridium complexes adopt bpy (2,2’-bipyridine)-type ancillaryligands, which makes it difficult to achieve blue light emission with high color purity.In the paper, an effective molecular design strategy to achieve blue-emitting ioniciridium complexes has been proposed, which is to insert electron-donating atoms intothe ancillary ligands to increase the LUMO (lowest unoccupied molecular orbital) levelsof the complexes. With pyrazole-type ancillary ligands, blue-green and blue-emittingcomplexes have been achieved. Compared to conventional bpy-type ancillary ligands,pyrazole-type ancillary ligands increase the LUMO levels of the complexes by0.27-0.31eV and shift the emission spectra of the complexes toward blue by more than100nm. The LEC based on the blue-emitting complex shows an electroluminescencepeak at460nm and CIE (Commission Internationale de l’Eclairage) coordinates of (0.20,0.28), indicating much better color purity than that of other reported blue LECs basedon ionic iridium complexes.With imidazole-type ancillary ligands, new ionic iridium complexes have beendesigned and synthesized. Imidazole-type ancillary ligands also significantly shift theemission spectra of the complexes toward the blue region of the spectrum. Bycontrolling the conjugation-length of imidazole-type ancillary ligands, a new series ofblue-green to red-emitting ionic iridium complexes has been achieved. Blue-green,green, yellow and orange-red LECs show peak current efficiencies of8.4,18.6,12.7and13.2cd/A, respectively. Because of the bulky side group attached to the complex,the efficiency of the blue-green LEC has been dramatically enhanced to18.3cd/A,which is the highest among blue-green LECs reported so far. By doping a small amount of red-emitting complexes into blue-green LECs, white LECs have been fabricated,which show CIE coordinates around (0.37,0.41), CRI (color rendering index) valuesaround80, and a peak current efficiency, external quantum efficiency and powerefficiency of11.4cd/A,5.6%and11.2lm/W, respectively. The efficiencies are thehighest among white LECs reported so far.The performances of ionic iridium complexes as phosphorescent dopants insolution-processed OLEDs have been systematically investigated. The peak currentefficiencies of blue-green, green, yellow and red OLEDs reach24.3,25.3,20.5and4.2cd/A, respectively. With ionic iridium complexes as the dopants, white OLEDs havebeen fabricated, which show a peak current efficiency, external quantum efficiency andpower efficiency of20.7cd/A,9.6%and8.5lm/W, respectively.更多还原