Effect of a multiple quantum well structure as an emissive layer based on blue phosphorescent organic light-emitting diodes

We demonstrate a multiple quantum well (MQW) structure with charge control layers (CCLs) to produce highly efficient blue phosphorescent organic light-emitting diodes (OLEDs). Three types of devices (A, B, and C) were fabricated with the following emitting layer structures while maintaining the thickness of the EMLs: host-emitter doping layers, nondoping layers, and CCLs. Triplet energies in such MQW devices were confined at the EMLs. The properties of a device with an MQW demonstrated a maximum luminous efficiency and external quantum efficiency of 18.33 cd/A and 9.47%, respectively. The device also showed a reduction in the turn-on voltage from 3.5 V to 2.5 V and an enhancement of the power efficiency. The described MQW device concept is considered to be useful for future OLED displays and light applications.