聚合物掺杂的高亮度磷光有机电致发光器件

采用新型贵金属铱的配合物(pbi)2Ir(acac)作为客体磷光发光材料, 分别以4%和5%(w)的浓度掺杂于聚合物主体材料poly(N-vinylcarbazole) (PVK)中, 利用旋涂工艺制备了结构为indium-tin oxide (ITO)/PVK:(pbi)2Ir(acac)/2,9-二甲基-4,7-二苯基-1,10-菲咯啉(BCP)/Mg:Ag的有机电致发光器件, 对磷光材料(pbi)2Ir(acac)的紫外-可见吸收光谱﹑光致发光光谱以及聚合物掺杂的磷光器件的电致发光特性进行了研究. 结果表明, 两种掺杂浓度的器件均具有8 V左右的启亮电压, 器件在启亮后的最大流明效率分别为1.53和1.31 lm·W-1, 最大亮度分别为11210和9174 cd·m-2; 同时, 器件的电致发光光谱与色坐标均不随偏置电压和客体掺杂浓度的变化而改变, 具有稳定的色纯度. 分析了主体材料PVK到磷光客体(pbi)2Ir(acac)的能量转移机制, 并探讨了随着器件电流密度和客体掺杂浓度的逐渐增加, 器件流明效率的变化趋势.

Polymer Doped High Brightness Phosphorescent Organic Light-Emitting Diodes

Polymer doped organic light-emitting diodes (OLEDs) with the structure of indium-tin oxide (ITO)/poly(N-vinylcarbazole) (PVK):(pbi)2Ir(acac)/2,9-dimethyl-4,7-diphenyl-1,10-phenan throline (BCP)/Mg:Ag were fabricated. The light-emitting layer was processed by doping noble metal iridiumcomplex (pbi)2Ir(acac) into a PVKmatrix with the concentrations of 4%and 5%(w), using spin coating method. Through characterizing the UV-Vis absorption spectrum, photoluminescence (PL) spectrum of the (pbi)2Ir(acac) and the electroluminescence (EL) properties of the devices, the main energy transfer mechanisms from phosphorescent material (pbi)2Ir(acac) to PVK were discussed. The device performance was investigated at different current densities and doping concentrations. The results showed that the devices with above two different doping concentrations have the maximum brightness of 11210 and 9174 cd·m-2 and maximum luminance efficiency of 1.53 and 1.31 lm·W-1, respectively. The EL spectrum and the Commissions Internationale de 1’Eclairage (CIE) coordinates were independent on the variation of bias voltage and the doping concentration, indicating a stable color purity.