Role of host excimer formation in the degradation of organic light-emitting devices

Abstract

Host-guest structures are used in most state-of-the-art organic light-emitting devices (OLEDs), where host molecules serve to dilute guest molecules, transport charge, and confine excitons on the guest. Hosts are often critical to achieving high efficiency and stability, yet predicting and understanding the effect of host properties on device stability is a persistent design challenge which slows the discovery of new OLED materials. Studying closely related carbazole hosts, we find that hosts which form an intermolecular triplet excimer state show faster degradation. Screening for excimer formation could accelerate discovery of stable host materials.