【作者】 丁勇；

【导师】 刘迪；

【作者基本信息】 大连理工大学 ， 有机化学， 2020， 硕士

【摘要】 有机电致发光材料在显示、照明和信息安全等领域展现出巨大的应用潜力。基于环金属铱（III）配合物的有机磷光材料可以同时利用三线态和单线态激子发光,从而实现100%的理论内量子效率。同时,磷光铱配合物还具有发光效率高、颜色易调节、寿命较短、良好的热稳定性及电化学稳定性等优点,近年来备受关注。目前绿光、黄光铱配合物的效率已经基本满足市场要求,而高性能的红光和近红外材料由于受能隙法则的限制（即波长越长,非辐射跃迁速率越大,辐射跃迁速率越小）,仍有待进一步开发。鉴于此,本论文设计、合成了一系列以2-苯基喹啉衍生物或2-芳基-6-三氟甲基苯并噻唑为主配体的新型橙红至深红色磷光铱配合物,对它们进行了光物理性质、电化学性质、理论计算及器件性能的研究,具体研究内容如下:1:文献报道的以2-芳基喹啉或其衍生物作为环金属配体的铱配合物通常发射橙红色磷光,发射波长低于600 nm。本文将三氟甲基（CF₃）或氟（F）引入喹啉环的6位,设计合成了主配体2-苯基-6-三氟甲基/氟基-喹啉（CF₃-phq或F-phq）,与acac或tmd等辅助配体混合配位得到铱配合物Ir（CF₃-phq）₂（acac）,Ir（CF₃-phq）₂（tmd）,Ir（F-phq）₂（acac）和Ir（F-phq）₂（tmd）。其中,含CF₃的铱配合物都能发射出饱和的红色磷光,发射峰位于627-630 nm。尤其是基于Ir（CF₃-phq）₂（tmd）的红色OLED实现了标准的红色电致发光,CIE坐标为（0.67,0.33）,最大亮度为12695 cd m^-2,最大外量子效率为14.96%。2:2-苯基苯并噻唑因其结构简单,易于修饰,配位能力强,配合物发光效率高等优点,一直作为铱配合物的配体骨架而受到广泛关注。但是以2-苯基苯并噻唑母体结构为主配体的配合物Ir（bt）₂（acac）发光波长在橙黄至橙红光波段,与标准红光甚至深红光波长还有一定的差距。本文在苯并噻唑环的2或6位上引入具有不同供电子能力和共轭程度的取代基,合成了四种主配体,并以acac和tmd为辅助配体与铱混合配位得到了七个新型铱配合物,这些新型配合物的发射波长都显示出30-100 nm的红移。修饰基团除了可以使发光光谱红移外,基团的空间位阻效应还能改善材料的发光效率和器件稳定性。以配合物M6为磷光发光体制备的橙色PhOLED器件D6,其EL谱最大发射波长为584 nm（母体为556nm）,最大亮度(L_max)为40252 cd m^-2,最大功率效率（η_p）为26.45 lm W^-1,最大外量子效率(η_ext)为15.97%。尤其值得注意的是,在10000 cd m^-2的高亮度下,该器件的外量子效率(?_ext)仍然高达12.50%,表明器件的效率稳定,效率滚降较小。更多还原

【Abstract】 Organic luminescent materials play a more and more important role in the fields of display,lighting and information security in recent years.Phosphorescent organic materials based on transition metal complexes as luminescent materials have drawn great interest since the strong spin-orbit coupling（SOC）and fast intersystem crossing could lead to a harvest of both singlet and triplet excitons in the emitting layer and achieve internal quantum efficiency as high as 100%theoretically.Among the reported heavy-metal complexes,Ir（III）complexes are considered as the most promising emitters in OLEDs based on their relatively high phosphorescence quantum yields,short triplet excited-state lifetimes,excellent color tunability from blue to deep-red and splendid thermal and electrochemical stability.Currently,great success has been acquired in green,yellow,and orange emitting complexes.Nevertheless,the highly efficient and stable saturated red to deep-red phosphorescent emitters remains an unresolved issue.According to the energy gap law,the nonradiative rates(k_nr)would increase,while the radiative rates（k_r）tend to decrease in the lower-energy regions of the visible spectrum（orange to red）.Meanwhile,the extension of the conjugated system would cause adjacent molecular packing,which lead to severe triplet-triplet annihilation（TTA）.In view of this,a series of novel orange-red to deep-red phosphorescent iridium complexes with 2-phenylquinoline derivatives or 2-aryl-6-trifluoromethylbenzothiazole as main ligands were designed and synthesized in this thesis.The photophysical properties,electrochemical properties,theoretical calculations and device performance were also studied.The specific research contents are as follows:1:Most of the reported iridium complexes with 2-arylquinoline or its derivatives as cyclometalating ligands are orange-red phosphorescent with peak wavelength below 600 nm.Herein,trifluoromethyl（CF₃）or Fluorine（F）is introduced into the 6-site of quinoline ring to design and synthesize the cyclometalated ligands 2-phenyl-6-CF₃/F-quinoline（CF₃-phq or F-phq）and heteroleptic iridium complexes Ir（CF₃-phq）₂（acac）,Ir（CF₃-phq）₂（tmd）,Ir（F-phq）₂（acac）and Ir（F-phq）₂（tmd）.Among them,the phosphorescence of CF₃–containing iridium complexes are saturated red with peaks at 627-630 nm.Especially the Ir（CF₃-phq）₂（tmd）based red OLED realized pure red electroluminescence with Commision Internationale de L’Eclairage（CIE）coordinates of（0.67,0.33）with a high brightness of 12695 cd m^-2 and a maximum external quantum efficiency of 14.96%,respectively.2:Because of the simple structure,easy modification,strong coordination ability,and high luminous efficiency and stability during device preparation,2-phenylbenzothiazole has been widely concerned as the ligand framework of iridium complexes.However,the luminescence wavelength of the complex Ir（bt）₂（acac）with 2-phenylbenzothiazole derivatives as the main ligand is in the range of orange to orange red,which is still a certain distance away from the wavelength of standard red light or even deep red light.Based on the above,we introduced substituents with different donor capabilities and different degrees of conjugation at the 2-or 6-position of the benzothiazole ring to synthesize four first ligands,and seven novel Iridium complexes were obtained using acac and tmd as auxiliary ligands.The emission wavelengths of these new complexes all show a red shift of 30-100 nm.In addition to the red-shift of the emission spectrum by the modified group,the steric effect of the group can also improve the luminous efficiency of the material and the stability of the device.The device D6 based on M6 showed a maximum emission of 584 nm（the parent is556 nm）,the maximum brightness(L_max)reached 40252 cd m^-2,the maximum power efficiency（?_P）was 26.45 lm W^-1 and the maximum external quantum efficiency(?_ext)was 15.97%with the CIE coordinate of（0.56,0.43）.It is worth noting that at a high brightness of 10000 cd m^-2,the external quantum efficiency(?_ext)is still as high as 12.50%,which is only a decrease of21.7%.This indicates that the efficiency of the device is stable and the roll-off is small.更多还原