Blue and white organic light-emitting devices using 2,5-diphenyl -1, 4-distyrylbenzene with two trans-double bonds as a blue emitting layer

Abstract

A novel derivative of oligo(phenylenvinylene) (OPV), 2,5-diphenyl -1,4-distyrylbenzene with two trans-double bonds (trans-DPDSB), is used as a blue emitting material in blue and white organic light-emitting devices (OLEDs). Blue devices with a configuration of indium-tin oxide (ITO)/N,N′ -diphenyl-N,N′ -bis(l-naphthyl)-(1,1′-biphenyl)-4,4′ -diamine (NPB)/ frww-DPDSB / tris (8-hydroxyquinoline) aluminum (Alq3)/LiF/Al are constructed, where NPB, Alq3 and frons-DPDSB are used as hole-transporting, electron-transporting and light-emitting layers, respectively. The color of emission is changed from blue-green to pure blue when the frans-DPDSB layer is thicker. By inserting an ultrathin 5,6,11,12-tetraphenylnaphthacene (rubrene) yellow light-emitting layer between the Alq3 and trans-DPDSB layers, white OLEDs are obtained. The maximum efficiency and luminance of the blue and white devices are 1.2,3.0 cd/A, and 1400,7000 cd/m2, respectively. © 2005 Trans Tech Publications, Switzerland.