Photoresponsive Luminescence Switching of Metal‐Free Organic Phosphors Doped Polymer Matrices

Abstract A new type of luminescence switching behavior based on phosphorescence enhancement from a series of metal‐free organic phosphors doped polymers by UV‐irradiation is investigated. This phenomenon is observed only from pairs of organic phosphors and polymer matrices having a combination of appropriate triplet exciton lifetime and oxygen permeability. Systematic investigation reveals that the luminescence switching behavior of organic phosphors embedded in a specific polymeric matrix stems from the conversion of triplet oxygens to singlet oxygens by UV‐irradiation, leading to the unique phosphorescence enhancement of organic phosphors. Visualization of latent information by UV‐irradiation is demonstrated toward novel secure information communication applications.