Review of Organic Persistent Phosphors: Classifications by Material Forms, Applications, and Mechanisms

Abstract Persistent luminescence (PersL) is the phenomenon of light emission that continues long after the excitation source is removed. This property holds high potential across diverse applications, from emergency signage to bioimaging and sensing. The history of persistent luminescence materials have progressed from ancient inorganic materials to modern organic systems. The organic PersL developed later are gaining momentum with discoveries in long‐lifetime organic phosphorescence and the advent of thermally activated delayed fluorescence (TADF), crucial for efficient OLEDs. This review systematically covers the major material forms of organic PersL materials, detailing their operating principles and typical applications. The fundamental theoretical principles governing long‐lasting emission are discussed, including mechanisms such as spin‐forbidden transitions, charge‐separated states, trap‐induced PersL, and chemiluminescence in organics. Finally, five diverse stimulation methods—thermal, optical, mechanical, electrical, and magnetic—that activate trap‐induced PersL are also explored. This review would help the understanding of organic persistent materials and open the versatility of these fascinating materials.