富勒烯掺杂NPB空穴传输层的有机电致发光器件

Fullerene-doped hole transport NPB layer in organic light-emitting devices

报道了不同掺杂浓度NPB:C60(富勒烯)作为空穴传输层对有机电致发光器件性能的影响.采用真空热蒸镀方法,制作了ITO/NPB:C60(x%)/Alq3/LiF/Mg:Ag结构的四种有机电致发光器件.当NPB:C60的掺杂浓度是15%时,器件的启亮电压是4 V,最大亮度是11000 cd/m2.然而,当NPB:C60的掺杂浓度是20%时,器件的最大亮度降低到6500 cd/m2,启亮电压升高到6 V.通过对器件发光机理的分析,掺杂浓度不同,空穴传输层的空穴迁移率不同.迁移率的不同是造成四种器件性能不同的主要原因.

The effect of C60 doping in the hole transport NPB layer on the performance of the device was investigated by changing the C6o content from 0 to 20 wt%. The OLEDs had a structure of ITO/NPB： C60 （0, 10, 15, and 20 wt % ）/Alq3/LiF/Mg： Ag. The doping led to higher hole mobility in C60-doped NPB layer from 5 wt% to 15wt%. Moreover, the hole mobility decreased when the doping content is 20%. The higher hole mobility resulted in efficient hole injection and low driving voltage at high luminance. For example, the driving voltage is about 4V and the maximum luminance of the OLEDs is 11000 cd/m^2 when the doping content is 15 %. However, the driving voltage is about 6V and the maximum luminance of the OLEDs is 6500 cd/m^2 when the doping content is 15 %. The hole mobility change resulted in the different performance in the devices.