摘要/Abstract
以聚（9，9-二己烷芴）（1）和聚（9，9-二（1-（4-己氧）苯）芴）（2）作为参照物，通过Suzuki偶联反应合成了侧链9位碳含有4-己氧基苯和2，4，6-三苯基-1，3，5-三嗪单元的芴共聚物3.聚合物1，2和3固体粉末的5%质量热损失温度分别是274，318和401℃，玻璃化转变温度分别是91，120和139℃.聚合物1，2和3在甲苯溶液中的最大吸收峰和荧光发射峰分别在380和435 nm.从聚合物1到聚合物3，薄膜的荧光发射最大半峰宽逐渐降低.大体积刚性吸电子2，4，6-三苯基-1，3，5-三嗪基团的引入，使聚合物1，2和3的热稳定性、蓝光发射的色纯度和光谱稳定性逐渐提高，不同工作电压驱动下聚合物3稳定的电致发光光谱进一步证明了这一点.聚合物1，2和3的最高占有轨道能级分别为－5.72，－5.95和－5.96 eV，最低未占有轨道能级分别为－2.70，－2.39和－2.43 eV.聚合物1，2和3的三线态能级分别为2.82，2.81和2.97 eV.聚合物1，2和3的单线态-三线态能级差分别是0.32，0.32和0.15 eV.4-己氧基苯的引入使聚合物的能隙变宽，而吸电子的2，4，6-三苯基-1，3，5-三嗪的引入使聚合物单线态-三线态能级差依次减少.聚合物1，2和3粉末均易于形成非晶薄膜.聚合物3粉末的有序性介于聚合物1和2之间，聚合物2侧链的烷氧基苯有助于提高固体粉末有序形态的多样化.综合结果表明，侧链含有刚性4-己氧基苯和2，4，6-三苯基-1，3，5-三嗪基团的无规共聚物3具有更佳的综合光电性质.
关键词: 聚芴, 蓝光, 侧基, 2,4,6-三苯基-1,3,5-三嗪, 光物理, 热稳定性
Polymer 3 based on 1-(4-hexyloxy)-benzene and 2,4,6-triphenyl-1,3,5-triazine functionalized fluorene units was synthesized and characterized, whose optoelectronic properties were further compared with those of poly(9,9-dihexyl-fluorene) (1) and poly(9,9-di(1-(4-hexyloxy)-phenyl)-fluorene) (2). The 5% weight loss temperatures of polymers 1, 2 and 3 thin solid powders are 274, 318 and 401℃, and their glass transition temperatures in the same state are 91, 120 and 139℃, respectively. The maximum absorption and photoluminescent emission peaks of polymers 1, 2 and 3 in toluene solution are 380 and 435 nm, and their optical band gaps in toluene solution are 2.95, 2.95 and 2.91 eV. The triplet energy levels of polymers 1, 2 and 3 are 2.82, 2.81 and 2.97 eV, while their singlet energy levels are 3.14, 3.13 and 3.12 eV, which makes the singlet-triplet energy splitting gaps for polymers 1, 2 and 3 to be 0.32, 0.32 and 0.15 eV. The highest occupied molecular orbital energy levels of polymers 1, 2 and 3 are -5.72, -5.95 and -5.96 eV and the lowest unoccupied molecular orbital energy levels are -2.70, -2.39 and -2.34 eV. The introduction of 4-hexoxybenzene widened the energy band gaps of the polymers, while the electron deficient 2,4,6-triphenyl-1,3,5-triazine made the single-triplet energy splitting gaps of the polymers successively decreased, but it did not endow polymer 3 with thermally activated delayed fluorescence characteristic. With the introduction of rigid and electron deficient 2,4,6-triphenyl-1,3,5-triazine into the 9-carbon of the fluorene units in the polymer, the thermal stability, color purity and photostability of blue light emitting solid were improved in the turn of polymers 1, 2 and 3, which were further validated by the stable electroluminescent spectra of polymer 3. The wide-angle X-ray diffraction results of the polymers 1, 2 and 3 powders show that all polymers have excellent amorphous properties in nature. The phase diversity of polymer 3 powder locates between those of polymers 1 and 2, and the alkoxyl phenyl substituted group on the polymer 2 side chain is helpful to improve the diversity of ordered morphology in solid powder. The random copolymer 3 exhibits much better photoelectric properties than those of polymers 1 and 2.
Key words: polyfluorene, blue light, pendant group, 2,4,6-triphenyl-1,3,5-triazine, photo physics, thermal stability
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