将DPVBi薄层插入结构为ITO/2T-NATA/NPB/DPVBi:DSA-ph/Alq3/LiF/Al有机荧光电致发光器件的发光层中,通过控制DPVBi插层的层数和位置,制备了高效率的蓝光器件.DPVBi薄层的引入增强了器件的电子注入,平衡了载流子在发光区的分布,同时DPVBi薄层的空穴阻挡作用,增大了发光层中激子的形成区域.当发光层中插入2层DPVBi薄层时,器件性能最佳,最大亮度为22790cd/m2,最大效率为6.77cd/A.与不含插层的器件相比效率提高了67.6%.该器件在亮度为1000cd/m2时效率为6.49cd/A,对应色坐标为(0.179,0.317).
We have fabricated high-efficiency blue fluorescence organic light-emitting diodes(OLEDs) with DPVBi inserted in the doping emmision layer(EML).The OLEDs with a configuration of ITO/2T-NATA/NPB/DPVBi:DSA-ph(inserted with DPVBi thin layer)/Alq3/LiF/Al are fabricated,using 2T-NATA as hole injection layer,NPB as hole transport layer,DPVBi:DSA-ph as emission layer and Alq3 as electron transport layer,respectively.The DPVBi thin layer inserted in EML leads to an increase in device efficiency as a results of an improvement of the balanced carrier injection,which results in an efficient radiative recombination in the emission zone.In addition,DPVBi ability of hole blocking can also be another reason for the improvement on the luminous gain.Hence,high radiative recombination is expected to take place in DPVBi:DSA-ph emission layer.This high efficient recombination results in high brightness and enhanced efficiency in our OLEDs.By optimizing the location and the number of layers of DPVBi thin layer,a maximum current efficiency of 6.77 cd/A is achieved at a current density 6.84 mA/cm2,which is nearly 67.6% more than that of non-inserted device.At a luminance of 1000 cd/m2,the current efficiency of the optimizing device is 6.49 cd/A at 6.7 V with a CIE(0.179,0.317).