An organic light-emitting device with ultrathin quantum-well structure as light emitting layer

Both phosphorescent materials and devices, which emit red and green light, already have great performance and breakthrough. The biggest challenge and bottleneck is the blue phosphorescent device, if we want to popularize phosphorescent organic light-emitting device (OLED) in the full-color panel. This paper brings a new quantum-well structure in light-emitting layer. We select the commonly used phosphor materials, N,N′-dicarbazoly-2,5-benzene (mCP) and bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III) (FIrpic). The structure of the device is indium-tin oxide (ITO)/N,N′-bis(naphthalene-1-y1)-N,N′-bis(phenyl)-benzidine (NPB)/di-[4-(N,N-ditolyl-amino)-phenyl]cyclohexane (TAPC)/mCP/FIrpic/mCP/4,7-dipheny1-1,10-phenanthroline (Bphen)/Mg:Ag. The blue OLED of good performance is achieved by adjusting the thickness of FIrpic. When the thickness of FIrpic is 0.2 nm and the Current density is 34.86 mA/cm2, the results show that the luminance of the device is 1000 cd/m2, then the luminous power efficiency of the device is 6.01 lm/W. Meanwhile, the light emitting mechanism of ultrathin quantum-well structure is well studied, the quantum confinement effect and the role of quantum well structure as the light-emitting layer in the blue phosphorescent devices are mainly analyzed.