Persistent Luminescence Materials at Various Sizes and their Applications

Abstract

Persistent luminescence is a singular property of some materials capable of storing excitation energy on traps or intrinsic defects of materials (see Fig. 1a). This energy is, once the excitation stopped, released by an emission of light that can spread out over several hours. If this property has been known for a very long time, the mechanisms involved are still controversial and new applications are envisaged. The current applications of these materials consist mainly in the signaling of emergency exits, needles and dials of watches and toys, but we have proposed these materials for new applications according to their form (nanomaterials, ceramics and even crystals) and their emission wavelengths (from visible to near infrared). These applications include at first bioimaging, a field that requires more sensitive tools and theranostic applications [1–3]. Thus, persistent near-infrared luminescence nanoparticles have recently been introduced to enable highly sensitive in-vivo optical detection and completely avoid tissue autofluorescence. Furthermore these persistent luminescence can be activated in vivo through living tissue or reactivated by photostimulation using highly penetrating low-energy photons from the red region of the visible spectrum [4–6] (see fig. 1b).