Strong upconverting and downshifting emission of Mn2+ ions in a Yb,Tm:NaYF4@NaLuF4/Mn:CsPbCl3 core/shell heterostructure towards dual-model anti-counterfeiting.

Herein, a Yb,Tm:NaYF4@NaLuF4/Mn:CsPbCl3 quasi-core/shell heterostructure is synthesized with the assistance of silica. The strong upconverting and downshifting emission of Mn2+ ions was observed in the nanocomposite with a quasi-core/shell structure. The FRET process further improves the energy utilization efficiency of PQDs for UCNPs, which depends on the quasi-core/shell heterostructure. Considering the dual-model fluorescence emission behavior of Mn2+ ions, the stable Yb,Tm:NaYF4@NaLuF4/Mn:CsPbCl3 nanocomposite is used in anti-counterfeiting applications.