Blue and white organic light-emitting devices based on 2,5,2′ ,5′-tetrakis(4′-biphenylenevinyl)-biphenyl

Abstract

Blue and white organic light-emitting devices using a novel dimerie trimeric phenylenvinylene (TPV) derivative , 2,5,2′,5′- tetraMs(4′-biphenylenevinyl)-biphenyl (TBVB) containing a biphenyl center are fabricated. Structures of these devices are simple, where tris (8-hydroxyquinoline) aluminum (Alq) and N,N′-diphenyl-N,N′-bis(1- naphthyl)-(1,1 -biphenyl)-4,4′ -diamine (NPB) are used as electron-transporting and hole-transporting layers, respectively. In blue device, TBVB is used as light-emitting layer. The peak of electroluminescent (EL) spectra of the device with TBVB is at 468 nm, and its maximum efficiency is greatly higher than that of the reported oligomer poly(phenylenvinylene) (PPV) devices. By inserting an ultra thin layer of rubrene between TBVB and Alq layers, a fairy pure white OLED with CIE coordinates of (0.33, 0.34) is realized. Its maximum luminances and efficiencies are 4025 cd/m 2 and 3.2 cd/A, respectively.