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

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.