Influence of microcavity structure on the properties of red phosphorescent organic light emitting devices

The microcavity organic light-emitting device(OLED) was fabricated with highly reflective Al cathode and the semitransparent Al anode.The device structure is as follows:Al(10 nm)/MoOx(Y nm)/NPB(40 nm)/TCTA(10 nm)/CBP:R-4B(4%)(30 nm)/BCP(10 nm)/AlQ(40 nm)/LiF(1 nm)/Al(100 nm),where R-4B is employed as red phosphor emitting layer.The effect of cavity length on OLED property is discussed in this paper.It′s indicated that the spectrum is narrowed and the color purity is increased.With the increase of MoOx thickness,the light-emitting peak changes from 600 nm to 668 nm.The optimal electroluminescent performance is observed in the sample with the MoOx thickness of 40 nm:the emitting peak wavelength is 608 nm,the full width at half maximum is 50 nm,the maximum brightness reaches 35 300 cd/cm2,and the maximum current efficiency is 23.5 cd/A.Red organic phosphor electroluminescent devices with stable luminescent properties are obtained.