基于2,4,6-三苯基-1,3,5-三嗪和芴单元的激基缔合物主体材料的制备与应用（英文）

Synthesis and Applications of Excimer Host Materials Based on 2,4,6-Triphenyl-1,3,5-triazine and Fluorene Moieties

设计合成了三种基于2,4,6-三苯基-1,3,5-三嗪和芴单元的双极性主体材料FTRZ,pTFTRZ和mTFTRZ.分别研究了它们的热稳定性、光物理性能、电化学性质和电致发光器件性能与分子的拓扑结构之间的关系.FTRZ,pTFTRZ和mTFTRZ的热分解温度均在400℃以上,pTFTRZ和mTFTRZ的玻璃化转变温度分别是103和120℃.化合物FTRZ,pTFTRZ和mTFTRZ在甲苯溶液中的光学带隙分别为3.24,3.29和3.24eV,它们的三重态能级分别为3.04,3.11和3.05eV.由于2,4,6-三苯基-1,3,5-三嗪平面间的π-π作用,化合物FTRZ,pTFTRZ和mTFTRZ在薄膜状态下形成激基缔合物,荧光发射光谱明显红移.最后研究了FTRZ,pTFTRZ和mTFTRZ作为客体发光分子2,4,5,6-四(9-咔唑基)-间苯二腈的主体材料在绿色热活化延迟荧光电致发光器件中的应用.以化合物FTRZ作为主体材料的绿色有机电致发光器件(OLED)表现出更好的电致发光性能,最大电流效率为6.7cd/A,最大外量子效率为2.07%,最大亮度为35718cd/m2,远优于以pTFTRZ和mTFTRZ作为主体材料的绿光器件.

Three new bipolar derivatives based on 2,4,6-triphenyl-1,3,5-triazine and fluorene moieties, namely FTRZ, pTFTRZ and mTFTRZ were designed and synthesized by using 9-(4-(hexyloxy)phenyl)-9H-fluorene, 2-bromo-4,6-diphenyl- 1,3,5-triazine, 2,4,6-tris(4-bromophenyl)-1,3,5-triazine, and 2,4,6-tris(3-bromophenyl)-1,3,5-triazine through palladium-catalyzed cross-coupling reaction, which were reported as hosts for thermally activated delayed fluorescence organic light-emitting diodes (OLEDs). The 1 H NMR, 13C NMR and MALDI-TOF-MS spectra were used to characterize the chemical structure of compounds FTRZ, pTFTRZ and mTFTRZ. Their thermal, photophysical and electrochemical properties as well as electroluminescent device performance were thoroughly investigated to correlate the optoelectronic properties with the topology-varied molecular structure. The thermal decomposition temperatures of compounds FTRZ, pTFTRZ and mTFTRZ are 427, 446 and 424 ℃ and their glass transition temperatures of compounds pFTRZ and mTFTRZ are 120 and 103 ℃, respectively. The optical band gaps of compounds FTRZ, pTFTRZ and mTFTRZ in toluene solution are 3.24, 3.29 and 3.24 eV, and their triplet energy levels are 3.04, 3.11 and 3.05 eV, respectively. Due to the π-π interaction between 2,4,6-triphenyl-1,3,5-triazine planes, compounds FTRZ, pTFTRZ and mTFTRZ form excimer in the thin film state. The electroluminescent properties of OLEDs using compounds FTRZ, pTFTRZ and mTFTRZ as the hosts and 2,4,5,6- tetrakis(carbazol-9-yl)-1,3-dicyanobenzene as the guest emitter were investigated. The green OLED of compound FTRZ as host material shows a peak emission at 510 nm with a maximum current efficiency of 6.7 cd/A, a maximum external quantum efficiency of 2.07% and a maximum brightness of 35718 cd/m2 . The efficiency roll-offs of the OLEDs hosted by compounds FTRZ and pTFTRZ at 20000 cd/m2 are 3% and 2%, which are much better than the same device hosted by compound mTFTRZ.