All Non-Dopant RGB Composing White Organic Light-Emitting Diodes

摘要

All non-dopant white organic light-emitting diodes(WOLEDs) have been realized by using solid statehighly fluorescent red bis(4-(N-(1-naphthyl)phenylamino)phenyl)fumaronitrile (NPAFN)and amorphous bipolar blue light-emitting 2-(4-diphenylamino)phenyl-5-(4-triphenylsilyl)phenyl-1,3,4-oxadiazole (TPAOXD), together with wellknown green fluorophore tris(8-hydroxyquinolinato)aluminum (Alq3). The fabricationof multilayer WOLEDs did not involve the hard-tocontroldoping process. Two WOLEDs, Device I andII, different in layer thickness of Alq3, 30 and 15 nm,respectively, emitted strong electroluminescence (EL)as intense as 25,000 cd/m2. For practical solid statelighting application, EL intensity exceeding 1,000cd/m2 was achieved at current density of 18-19mA/cm2 or driving voltage of 6.5-8 V and the devicesexhibited external quantum efficiency (ηext) of2.6～2.9% corresponding to power efficiency (ηP) of2.1～2.3 lm/W at the required brightness.