Multichannel Control of PersL/Upconversion/Down-Shifting Luminescence in a Single Core-Shell Nanoparticle for Information Encryption.

ABSTRACT

Persistent luminescence (PersL) has been attracting substantial attention in diverse frontier applications such as optical information security and in vivo bioimaging. However, most of the reported PersL emissions are based on the dopants instead of the host matrix, which also plays an important role. In addition, there are few works on the PersL-based multifunctional nanoplatform in nanosized materials. Here, we report a class of novel nanostructure designs with PersL, upconversion, and down-shifting luminescence to realize the fine-tuning of emission colors under different excitation modes including steady-state irradiation, time-gating, and PersL generation. Blue, orange, and green emissions were easily achieved in such a single nanoparticle under suitable excitation modes. Moreover, the physical origin of the PersL of the CaF2 matrix was discussed by simulating the energy band structure with CaxFy defects. Our results provide new opportunities for the design of a new class of multifunctional materials, showing great promise in the field of information encryption security and multilevel anticounterfeiting.