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'-spirobifluorene (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.