Nano-structure enhanced organic light emitting diodes made with CdSe(ZnS) quantum dots and a semiconducting polymer

In this study, we report experimental results on the bilayer light emitting diodes made with organic capped CdSe(ZnS) core/shell type semiconductor nanocrystals and an electroluminescent semiconducting polymer, poly[2-phenyl-3-(9,9-dihexyl-fluoren-2-yl)phenylene vinylene]-co-[5-methoxy-2-((2´-ethylhexyl)oxy)phenylenevin ylene]. The device with the configuration ITO/PEDOT/CdSe(ZnS) and polymer blend/Ca/Al was fabricated. The pure polymer device emits yellow light with maximum brightness of 3949 cd/m² and maximum external quantum efficiency of 0.27 cd/a at 10 V, after blending with the CdSe(ZnS) quantum dots, the pled device shows much high brightness and external quantum efficiency and lower driving voltage. The maximum brightness is as high as 8192 cd/m² with maximum external quantum efficiency of 1.27 cd/a at 7 V.