芴-alt-咔唑类电磷光共聚物的发光性能

用共聚合方法将金属配合物引入共轭大分子链,使配合物之间的相互作用减少,有利于磷光体的均匀分散,增加在聚合物基体中的稳定性。将配合物引入共轭聚合物主链,在发光过程中主体链段既能将能量传递到客体,同时和配合物相邻的主体单元又能与配合物形成新的配体结构。共聚单元与配合物配体连接点的位置和键角的不同,影响聚合物的发光波长和发光效率。本文利用苯基异喹啉苯环上间位的溴将二(苯基异喹啉)乙酰丙酮合铱,通过Suzuki缩聚反应引入芴-咔唑交替共聚物主链,得到一种新型电磷光红光聚合物。聚合物器件的EL光谱发光波长为623nm,最大外量子效率为2.8%。

Luminescent Performances of Electrophosphorescent Copolymers Based on Fluorene-alt-Carbazole

Electrophosphorescent light-emitting diodes,for which both singlet and triplet excitons contribute to the light emission,have attracted great scientific and commercial attention because of their high quantum efficiency.Iridium-based complexes are the popular selection as the efficient dopant due to a relatively short phosphorescent lifetime.The electrophosphorescent polymers with iridium complex as a repeat unit incorporated into a conjugated main chain were investigated.In this case,the conjugated segments play the roles:a polymer ligand and a host for the energy transfer system.In this kind of phosphorescent polymers,the position and angle will affect the light wavelength and light efficiency of the PLEDbased on them.We demonstrated the efficient synthesis of the copolymers with Ir complexes incorporated onto fluorene-alt-carbazole backbone by Suzuki polycondensation via brominated iridium (Ⅲ) bis (1-phenylisoquinolyl-N,C2’) acetylactonate.With the different feed ratio from 0.1% to 0.5%,four polymers,named by PFCzIrPiq 01,PFCzIrPiq 02,PFCzIrPiq 03,and PFCzIrPiq05,were synthesized respectively.The resultant copolymers are easily soluble in common solvents such as toluene,tetrahydrofuran and chloroform,which provides for the facility in preparation of the polymer films by spin coating.The maximum external quantum efficiency of 2.8% and luminescent efficiency of 1.3 cd/Awere obtained from the device fabricated with copolymer PFCzIrPiq05.It indicates that the introducing complexes onto polymer backbone may be a better way to improve the efficiency of phosphorescent polymers in light-emitting diodes.