Lanthanide and Heavy Metal Free Long White Persistent Luminescence from Ti Doped Li-Hackmanite: A Versatile, Low-Cost Material

Persistent luminescence (PeL) materials are used in everyday glow-in-the-dark applications and they show high potential for, e.g., medical imaging, night-vision surveillance, and enhancement of solar cells. However, the best performing materials contain rare earths and/or other heavy metal and expensive elements such as Ga and Ge, increasing the production costs. Here, (Li,Na)(8)Al6Si6O24(Cl,S)(2):Ti, a heavy-metal-and rare-earth-free low-cost material is presented. It can give white PeL that stays 7 h above the 0.3 mcd m(-2) limit and is observable for more than 100 h with a spectrometer. This is a record-long duration for white PeL and visible PeL without rare earths. The material has great potential to be applied in white light emitting devices (LEDs) combined with self-sustained night vision using only a single phosphor. The material also exhibits PeL in aqueous suspensions and is capable of showing easily detectable photoluminescence even in nanomolar concentrations, indicating potential for use as a diagnostic marker. Because it is excitable with sunlight, this material is expected to additionally be well-suited for outdoor applications.