Phosphorescent Organic Light-emitting Devices: Triplet Energy Management

Abstract

This review paper describes the device performance and light-emission mechanism for phosphorescent organic light-emitting devices (OLEDs), as well as energy transfer processes in phosphorescent host-guest systems. The characteristics of a green phosphorescent OLED, with representative guest and host materials, are presented and its working mechanism is discussed. To improve the emission efficiency, the confinement of triplet energy in the guest molecules is demonstrated for a blue phosphorescent OLED. Photoluminescence phenomena in phosphorescent host-guest systems are presented, and the energy transfers between the host and guest molecules are also discussed.