An organic light-emitting devices of highly efficient white phosphor using an electron/exciton blocker

Highly efficient white phosphorescent organic light-emitting devices (WOLEDs) was fabricated using an electron/exciton blocker. The device structure is ITO/2T-NATA(25 nm)/ NPBX(25-dnm)/CBP:5%Ir(ppy)3:0.5%Rubrene(8 nm)/NPBX(dnm)/ DPVBi(30 nm)/TPBi(20 nm)/Alq(10nm)/LiF(1nm)/Al, in which N,N ’-bis- (1-naphthyl)- N,N ’-diphenyl -1, 1 ’- bi- phenyl-4,4 ’-diamine (NPBX) functions as a hole transport layer and electron/exciton blocker, 4,4,N,N ’- dicarbazolebiphenyl (CBP) is host, 4,4’-bis(2,2 -diphenyl vinyl)-1,1 ’-biphenyl (DPVBi) is blue fluorescent dye, 5,6,11, 12,-tetraphenylnaphthacene (rubrene) is fluorescent dye, factris (2-phenylpyridine) iridium (Ir(ppy)3) is phosphorescent sensitizer and tris(8-hydroxyquinoline) aluminum (Alq3) is an electron transport layer. The WOLEDs have obtained white light emission by adjusting the thickness of NPBX , when the concentration of Ir(ppy)3 is 5-wt% and rubrene is 0.5-wt%, respectively, the thickness of the doped emissive layer is 8 nm, the WOLEDs show a maximum luminous efficiency is 11.2 cd/ A with d of 10 nm at 7 V and a maximum luminance of 28170 cd/m2 at 17 V, the CIE coordinates is (0.37.0.42), which is in white region.