Encoding Multilayer Complexity in Anti‐Counterfeiting Heterometallic MOF‐Based Optical Tags

Abstract

Optical tags provide away to quickly and unambiguously identify valuable assets.C urrent tag fluorophore options lackt he tunability to allowc ombined methods of encoding in as ingle material. Herein we report ad esign strategy to encode multilayer complexity in af amily of heterometallic rare-earth metal-organic frameworks based on highly connected nonanuclear clusters.T oi mpart both intricacy and security,asynergistic approach was implemented resulting in both overt (visible) and covert (near-infrared, NIR) properties,w ith concomitant multi-emissive spectra and tunable luminescence lifetimes.T ag authentication is validated with av ariety of orthogonal detection methodologies.I mportantly, the effect induced by subtle compositional changes on intermetallic energy transfer,a nd thus on the resulting photophysical properties,i sd emonstrated. This strategy can be widely implemented to create alarge library of highly complex, difficult-to-counterfeit optical tags.

Dramatic Enhancement of Rare-Earth Metal–Organic Framework Stability Via Metal Cluster Fluorination

“…The basis for all hydroxyl and fluorine structures came from experiment; Zr-UiO-66­[REF], Eu-DOBDC, and Eu-TCPB. , Each structure underwent four calculations using the Vienna Ab initio Simulations Package (VASP) − code to optimize the structure, which allowed the atomic position to change while the volume was kept constant, to then optimize the atomic positions and the cell volume simultaneously, and to then, finally, optimize the atomic positions only. All calculations used large core potentials for the RE­(III) oxidation state and a 500 eV cutoff using the PBEsol exchange-correlation functional .…”

Laterally Engineering Lanthanide‐MOFs Epitaxial Heterostructures for Spatially Resolved Planar 2D Photonic Barcoding

“…As shown in the scanning electron microscopy (SEM) images in Figure 2a-c, the developed Ln-MOF MOFs microrods and microplates have smooth surfaces,w hich exhibit clear 1D morphology and regular rectangular or square shapes,r espectively.T he synthesized MOFs microparticles display almost the same Fourier-transform Infrared (FTIR) spectra with the initial microrods (Figure S9), suggesting that these MOFs have the similar chemical composition and coordination structures.T he as-prepared Ln-MOFs demonstrate excellent thermostability and high stability under various environments (Figure S10,11), which endow them with practical applications abilities for security labels. [16,17]…”

“…The synthesized MOFs microparticles display almost the same Fourier‐transform Infrared (FTIR) spectra with the initial microrods (Figure S9), suggesting that these MOFs have the similar chemical composition and coordination structures. The as‐prepared Ln‐MOFs demonstrate excellent thermostability and high stability under various environments (Figure S10,11), which endow them with practical applications abilities for security labels [16, 17] …”

Tunable fluorescence emission based on multi-layered MOF-on-MOF

“…Metal-organic frameworks (MOFs) as an emerging class of crystalline porous coordination materials constructed from metal ions or metal clusters and organic ligands have attracted tremendous attention. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] In particular, luminescent MOFs, a sub-category of MOFs, showed great potential in various applications such as bio-imaging, [16][17][18][19][20][21] sensing, [22][23][24][25][26][27][28] anti-counterfeiting/encryption [29][30][31][32][33][34] and white-light-emitting diodes [35][36][37][38] due to their diverse and easily tunable structures and physicochemical properties. To date, luminous sources of MOFs mainly cover three categories, including endogenous organic linkers, [39][40][41][42][43][44] metal ions or clusters, [45][46]…”