White organic light-emitting devices based on fac tris(2-phenylpyridine) iridium sensitized 5,6,11,12-tetraphenylnap-hthacene

We have fabricated the white organic light-emitting devices(WOLEDs) based on 4,4′-bis(2,2 -diphenyl vinyl) -1,1′-biphenyl(DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene(rubrene) . The device structure is ITO/2T-NATA(20 nm) /NPBX(20 nm) /CBP:x%Ir(ppy) 3:0.5% rubrene(8 nm) /NPBX(5 nm) /DPVBi(30 nm) /Alq(30 nm) /LiF(0.5 nm) /Al. In the devices,DPVBi acts as a blue light-emitting layer,the rubrene is sensitized by a phosphorescent material,fac tris(2-phenylpyridine) iridium [Ir(ppy) 3],acts as a yellow light-emitting layer,and N,N′-bis-(1-naphthyl) -N,N′iphenyl -1,1′-biphenyl-4,4′-diamine(NPBX) acts as a hole transporting and exciton blocker layer,respectively. When the concentration of Ir(ppy) 3 is 6wt%,the maximum luminance is 24960 cd/m2 at an applied voltage of 15 V,and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.