Energy transfer-driven multicolor long persistent luminescence nanocomposites Sr2MgSi2O7:Eu2+,Dy3+@CsPbI3-SiO2: Green preparation and advanced anti-counterfeiting

Achieving diverse persistent colors is an important strategy for the application of long persistent phosphors in anti-counterfeiting. Utilizing the light conversion of perovskite quantum dots is an important approach. However, achieving rapid, in-situ, and green fabrication of perovskite quantum dots (QDs) on the surface of long persistent phosphors remains a key challenge. This work proposes a strategy: adsorbing an aqueous CsPbI 3 solution into the porous silica layer on the surface of Sr 2 MgSi 2 O 7 :Eu 2+ ,Dy 3+ (SMS), followed by rapid drying to generate CsPbI 3 QDs in situ. This approach enables efficient fabrication of the nanocomposite Sr 2 MgSi 2 O 7 :Eu 2+ ,Dy 3+ @CsPbI 3 -SiO 2 (MISNs) while preserving the crystallinity of CsPbI 3 QDs. Interestingly, MISNs exhibit differential luminescence under excitation with light of varying wavelengths, even after removal of the excitation source, CsPbI 3 QDs can absorb long persistent luminescence (LPL) energy from SMS and convert it into their own fluorescent (FL) emission, thereby enhancing the concealment capability for advanced anti-counterfeiting. MISN-based luminescent inks can be deposited on common substrates (e.g., glass, aluminum foil, rubber) to form stable multicolor anti-counterfeiting marks. This study offers novel insights into the multicolor development of long persistent phosphors and the advancement of anti-counterfeiting technologies.