Study on luminescence characteristics of blue OLED with phosphor-doped host-guest structure

In this study,we design and fabricate phosphor-doped host-guest structure organic light-emitting diodes(OLEDs),where the blue-ray iridium complex electrophosphorescent material FIrpic acts as object material.Properties of the device can be accommodated by changing the host materials,dopant concentration and thickness of the light-emitting layer.The study shows that the host material N,N'-dicarbazolyl-3,5-benzene(mC P)has a higher triplet excited state energy level,which can effectively prevent FIrpic triplet excited state energy backtracking to host material,thus the luminous efficiency is improved.When mC P is selected as the host material,the thickness of the light-emitting layer is30 nm and the dopant concentration is 8 wt%,the excitons can be effectively confined in the light-emitting region.As a result,the maximum current efficiency and the maximum brightness of the blue device can reach 15.5 cd/A and7 196.3 cd/m^2,respectively.