铱-芴主链型共聚物的合成与光致发光性能

Synthesis and Photoluminescence Properties of Iridium-Fluorene Main-Chain Copolymers

合成以2-(4-溴苯基)苯并咪唑为环金属配体、乙酰丙酮为辅助配体的铱配合物客体单元,并通过Suzuki缩聚方法将客体引入聚芴(PFO)主体中,合成了主链型共聚物。通过元素分析、红外光谱、1 H-NMR等分析手段对产物进行了结构表征,通过紫外吸收光谱、稳态和瞬态荧光光谱对铱配合物、共聚物的光物理性能进行了研究。结果表明:铱配合物最大发射峰位于505nm和535nm,为绿光发射;共聚物同时呈现蓝光主体PFO和绿光客体铱配合物的发射,且随铱配合物含量提高,绿光强度明显增强,显示了主客体能量的部分转移,通过调节共聚物中铱配合物单元的含量,使共聚物的发光颜色从蓝光向绿光转移;当铱配合物的物质的量分数为2%时,蓝色荧光强度大于绿色磷光,共聚物色坐标刚好处于蓝绿交界处,当铱配合物物质的量分数大于2%时,共聚物呈现绿色发光;与铱配合物的荧光量子效率(2.7%)相比,共聚物的荧光量子效率均有显著增加;共聚物热稳定性良好。

The cyclometalated iridium complex based on 2-（4-bromophenyl）-benzimidazole as main ligand and acetylacetonate as ancillary ligand was prepared and then introduced in polyfluorene（PFO）subject through Suzuki polycondensation to obtain the main-chain copolymers.The iridium complex and copolymers were characterized by elemental analysis,FT-IR,1 H-NMR,UV and fluorescence spectroscopy.Results showed that the iridium complex emitted green-light with maximum peaks at 505 nm and 535 nm and the copolymers exhibited blue emission of PFO subject and green emission of iridium complex.The green light intensity was enhanced with the increasing of iridium complex content,which indicated that there existed partial transfer of energy between the subject and object and the emission color of copolymers shifted from blue to green by adjusting the proportion of the iridium complex.When the iridium complex mole fraction reached 2%,the color coordinates of copolymer just appeared at the junction of blue and green area and the blue fluorescence intensity was greater than the green phosphor,but the copolymer exhibited green-light emission when the mole fraction of iridium complex was greater than 2%.The copolymer fluorescence quantum efficiency was significantly improved compared with the phosphorescent iridium complex（2.7%）and the copolymer had good thermal stability.