Design of multilayer structure for UV organic light-emitting diodes based on 2-(2-naphthyl)-9,9′-spirobifluorene

With the goal of obtaining UV organic light-emitting diodes (UV OLEDs), the device architecture of OLEDs containing a novel UV-emitting material, 2-(2-naphthyl)-9,9′-spirobifiuorene (2SBFN), has been studied. UV emission from the 2SBFN layer was attained by employing the multilayer structure where poly(3,4-ethylene dioxythiophene) doped with poly-(styrene sulfonate) (PEDOT:PSS) was used as a hole-injection layer (HIL), while using conventional materials such as 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino] triphenylamine (mMTDATA) and copper phthalocyanine (CuPc) as HIL resulted in the emission from a material other than 2SBFN. These results suggest that the appropriate choice of HIL material is of critical importance in obtaining UV OLEDs.