一步法合成螺双芴及螺氧杂蒽衍生物及其在有机发光二极管中的应用:性能增强及相关的光学现象（英文）

One-Step Synthesis of Spirobi [fluorene] and Spiro [fluorene-9,9′-xanthene] Derivatives and Their Applications in Organic Light-Emitting Devices:Performance Enhancement and Related Optical Phenomena

以芴为原料,以钯为催化剂一步合成了2-(9-苯基芴基)-9,9′螺二芴(PF-SBF)。以PF-SBF作为有机发光二极管的发光及主体材料(FIrpic为磷光客体)时,观察到了不同于PF-SBF及FIrpic发光的红光带。这分别源于PF-SBF分子间的聚集和发光层/传输层诱导的激基复合物。通过选择合适的空穴和电子传输层,有效抑制了激基复合物的发光。同时,PF-SBF和TAPC双主体的结构不仅实现了纯FIrpic和Ir(ppy)_3蓝光和绿光,还大幅提升了器件性能。蓝光、绿光器件的最大电流效率和最大亮度分达到16.7、50.5 cd?A^(-1)和7857 cd?m^(-2)(11 V)、23390 cd?m^(-2)(8 V)。另外,除了PF-SBF,利用相似的合成方法,我们也合成了2-(9-苯基芴基)-9,9′螺芴氧杂蒽(PF-SFX),其较大的三线态能级(2.8 eV)较PF-SBF更适合做蓝光主体。以TAPC和PFSFX为双主体的器件最大电流效率提升到了22.6 cd?A^(-1)。所有实验结果均表明,PF-SBF和PF-SFX是构建高效绿光/蓝光磷光主体材料的有效结构单元。

Employing fluorene as substrate,we synthesized a new spirobifluorene derivative,2′-（9-phenylfluoren-9-yl）-9,9′-spirobi[fluorene]（PF-SBF）,through a one-step palladium-catalyzed cross-coupling reaction.Utilizing PF-SBF as an emitter and as a host of the blue phosphor bis（3,5-difluoro-2-（2-pyridyl）phenyl-（2-carboxypyri-dyl））iridium（III）（FIrpic） in organic light-emitting devices（OLEDs）,we observed a red light band different from the intrinsic blue emission of PF-SBF and FIrpic.This was attributed to the intermolecular aggregation of PF-SBF and to exciplexes generated at the interfaces of the emitting layer and the electron transport layer.The exciplex emission was then restrained through a suitable selection of hole and electron transport layer.Employing PF-SBF with di-[4-（N,N-ditolyl-amino）-phenyl]cyclohexane（TAPC） as a cohost,we obtained high-performance blue and green emissions from FIrpic and tris（2-phenylpyridine）iridium（III）（Ir（ppy）3）.The maximum current efficiencies and luminances of the blue and green OLEDs were as high as 16.7 and 50.5cd？A^（-1） and 7857（at 11 V） and 23390 cd？m^（-2）（at 8 V）,respectively.As an alternative to PF-SBF,we also synthesized a new xanthene derivative,2-（9-phenyl-fluoren-9-yl）spiro[fluorene-9,9′-xanthene]（PF-SFX）,with a large triplet energy level of 2.8 e V.Using PF-SFX similarly as a host of FIrpic,the current efficiency and luminance were significantly improved to 22.6 cd？A^（-1） and 6421 cd？m^（-2）（at 10 V）.These results demonstrate the potential of PF-SBF and PF-SFX as new building blocks for high-efficiency green/blue phosphorescent host materials.