Dual-Mode Luminous Lead-Free Cs₃Cu₂Cl₅ Perovskite Embedded in UiO-66-NDC Nanoparticles for Multilevel Anti-Counterfeiting

Optical anti-counterfeiting technology has been considerably developing in the field of information security and confidentiality. Hence, the growing demand for optical anti-counterfeiting technology requires eco-friendly and stable materials with multimodal fluorescence to improve the difficulties in information decryption. Herein, a dual-mode-emission Cs 3 Cu 2 Cl 5 /UiO-66-NDC (CCL/UiO) nanocomposite has been fabricated by growing lead-free Cs 3 Cu 2 Cl 5 nanocrystals (5–7 nm) in the pores (5–8 nm) of UiO-66-NDC (1,4-naphthalenedicarboxylic acid) via a nanoconfinement strategy. The as-obtained nanocomposite exhibited distinctly luminous green (530 nm) and blue (418 nm) colors from the emission of Cs 3 Cu 2 Cl 5 and UiO-66-NDC under 254 and 365 nm excitation, respectively, implying that the nanocomposites displayed excitation-wavelength-dependent emission. We evaluated the possibility of associating the as-achieved CCL/UiO ink with other devices, such as printer and pen, to improve the efficiency of anti-counterfeiting pattern preparation. Moreover, a multilayered anti-counterfeiting structure was constructed by combining CCL/UiO and UiO-66-NDC layers to improve the difficulties of information decipherment. This work provides a valuable research inspiration for the design and preparation of multimodal anti-counterfeiting materials.