Facile Synthesis of a Color-Tunable Microcrystal Phosphor for Anti-Counterfeit Applications.

Developing luminescent materials with tunable emission colors provides exciting opportunities for application in the display, anti-counterfeiting, and optical sensors. Here, we report a convenient, versatile approach to synthesize color-tunable, up/down-conversion luminescence in an inorganic host material. The emission color can be tuned by varying the excitation wavelength, allowing dynamic color tuning in the visible spectrum. We demonstrate that an unprecedented luminescence tunability from these phosphors can be achieved by tailoring the intensity ratio of different emission peaks. These findings provide valuable insights into controlling multiple emission color processes while offering the possibility for dynamic anti-counterfeiting and visual sensing of ultraviolet light in the range from 250 to 320 nm. These results open the opportunity for developing next-generation stimuli-responsive luminescent materials and smart devices.