Constructing perovskite-like oxide CsCa2Ta3O10: Yb, Er@Cs(PbxMn1-x) (ClyBr1-y)3 perovskite halide composites for five-dimensional anti-counterfeiting barcodes applications

Developing a secure and unclonable anti-counterfeiting technology with more dimensional encryptions is urgently demanded. All-inorganic halide perovskites hold great potential for applications in advanced fluorescence anti-counterfeiting owing to their superior optical properties, such as tunable emission colors, narrow emission peaks, etc. By further utilizing the feasibility of anion exchange for perovskite halides, this research successfully designs five-dimensional (5D) anti-counterfeiting barcodes with core-shell-like structured perovskite-like oxide and perovskite halide composites. The composites are prepared by a facile synthesis method, which includes adhesive growth of Cs(PbxMn1-x)(ClyBr1-y)(3) on the surface of CsCa2Ta3O10: Yb, Er (abbreviated as CCTO: Yb, Er@CsMX3) via sharing Cs+ at the interface. The unique structure makes it possess sensitivity to some additive decrypted inks, offering one more intriguing anti-counterfeiting dimension beyond the common dual-mode fluorescence and time-gating technique. The CCTO: Yb, Er@CsMX3 composites exhibit typical green upconversion (UC) luminescence under a 980 nm laser, red or green or blue (RGB) emission under ultraviolet (UV) light irradiation, ns-ms emission decay time, and changeable emission color when treated with decrypted inks. The fluorescent inks and barcodes are simple for fabrication, efficient for coding, easy for viewing and difficult for cloning, making them promising for anti-counterfeiting applications.