Comparison of two methods of improving the characteristics of a double-color white organic light-emitting diode

Abstract

White organic light-emitting diode was realized by co-doping a blue dye p-di(p-N,N-diphenyl-amino-styryl)benzene(DSA-ph) and a red dye 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran(DCJTB) into a blue host 2-(t-butyl)-9,10-di(2-naphthyl)anthracene(TBADN), achieving a brightness of 11580 cd/m2 at 200 mA/cm2, and a maximum current efficiency of 7.53 cd/A. The improvement was due to efficiency energy transfer from host to guest by the aid of assistant energy transfer mechanism. The device introduced a (4,4'-N,N'-dicarbazole)biphenyl/4,4'-bis(N-carbazolyl)biphenyl(CBP) interlayer between separate double emissive layers with the same materials showed improved color stability, due to the blocking effect of the CBP layer, which contributed to stable and even exciton distribution in both blue and red emission layer.