Epitaxial\nGrowth\nof Multicolor Lanthanide MOFs by\nUltrasound for Photonic Barcodes

Epitaxially\ngrown lanthanide metal–organic frameworks\n(Ln\nMOFs) exhibit multicolor and characteristic Ln emission with sharp\nemission bands, which are of great value in the field of information\nsecurity and anti-counterfeiting. Epitaxial growth of Ln MOFs is generally\nachieved by solvothermal or hydrothermal methods, which suffer from\nchallenges such as high reaction temperature and long growth time.\nHere, we report the fast epitaxial growth of multicolor lanthanide\nMOFs by an ultrasonic method at room temperature. The TbSmSQ shows\na core–shell type structure with the Tb ion in the core and\nSm in the shell within one crystal and exhibits the characteristic\nemission lines of Tb and Sm, respectively. The nonporous structure\nand large distance between lanthanide ions effectively avoid the influence\nof solvent vapor on the intensity and color of luminescence emission.\nIts application as photonic barcodes has been studied. This work demonstrates\nthe feasibility of epitaxial growth of multicolor Ln MOFs by the ultrasonic\nmethod and its value for anti-counterfeiting and information security\napplications.