Abstract: Green organic light-emitting devices with the structure of indium-tin-oxide (ITO)/polystyrene(PS)∶N,N’-bis-(3-naphthyl)-N,N’-biphenyl-(1,1’-biphenyl)-4,4’-diamine (NPB)/tris-(8-hydroxyquinoline)-aluminum (Alq3)/Mg∶Ag were fabricated.A doping system consisting of small-molecular hole transporting material NPB and polymeric matrix polystyrene (PS) was employed as the compound hole transporting layer (HTL),and the thin film preparation was simplified via the spin-coating technique.By adjusting the component ratio of the system,we constructed several devices with different concentration proportions of PS∶NPB.The electroluminescent characteristics of the devices were investigated and discussed.The results demonstrate that the doping concentration of NPB has a remarkable impact on the optoelectric performance of both the HTL and the device.Optimum device performance could be obtained by choosing the best concentration proportion of PS∶NPB to be 1∶1.This contributes to the construction of compound functional layers of OLED devices and to the technical improvement.

Key words: organic light-emitting device, polystyrene, compound hole transporting layer, device performance