Highly crystalline persistent luminescent glass-ceramic for optical anti-counterfeiting

In-situ glass crystallization provides a unique platform to create hybrid materials with improved performances for emerging photonics applications. Here we report the design of a glass ceramic embedded with Ca2MgSi2O7: Eu2+ akermanite under the guideline of CaO-MgO-SiO2 phase equilibrium. The growth of the akermanite from ultrasmall spherical nanoparticles to highly orientated dendrites is experimentally controlled. Notably, the resulting orientated dendritic glass ceramic achieves high crystalline up to 90.1 % due to the homogeneous congruent crystallization, and transparency as result of the reduced light scattering. Thanks to metastable electric carriers trapping center with ideal trap depth of 0.52-0.70 eV, and sunlight excitable properties of the crystallized akermanite, as revealed by thermoluminescence technique, the developed glass ceramic exhibits impressive optical storage capability. This highly crystalline glass ceramic coupling with excellent optical properties and chemical/physical stability is of particular interests for a wide range of applications in the safety field and high security fluorescent anti-counterfeiting.