Aggregation induced emission based active conjugated imidazole luminogens for visualization of latent fingerprints and multiple anticounterfeiting applications

Abstract

Aggregation-induced emission based organic heterocyclic luminogens bearing conjugated electronic structures showed much attention due to its excellent fluorescence in aggregation state. In this communication, a novel conjugated blue light emitting imidazole molecule is synthesized by one pot multicomponent reaction route is reported for the first time. The prepared molecule exhibits a strong fluorescence in aggregation state with exceptional properties, such as high purity, inexpensive, eco-friendly, large scale production, high photostability, etc. By considering these advantages, a new fluorescence based platform has been setup for in-situ visualization of latent fingerprints and its preservation by spray method followed by Poly(vinyl alcohol) masking. A clear and well defined fluorescence fingerprint images are noticed on variety of surfaces by revealing level 1–3 ridge features upon ultraviolet 365 nm light exposure. The dual nature of binding specificity as well as excellent fluorescence properties permits the visualization of latent fingerprints for longer durations (up to 365 days) with superior contrast, high sensitivity, efficiency, selectivity and minimal background hindrance. We further fabricated unclonable invisible security ink for various printing modes on valuable goods for protection against forging. The developed labels are displaying uniform distribution of ink and exceptional stability under various atmospheric environments. The development of long preservative information using aggregation-induced emission based luminogen opens up a new avenue in advanced forensic and data security applications.

Chiroptical Nanocellulose Bio‐Labels for Independent Multi‐Channel Optical Encryption

“…Adding 3D patterns to labels using microprinting and gravure printing can greatly increase the security level of anti-counterfeit encryption, but the feature size of the physical patterns in currently reported multi-channel integrated encryption labels rarely reaches microscopic scale, especially closer to the nm level. [55,63,64] In contrast, our bio-labels could further enrich the encryption channels through extending data encryption capability from single flat 2D planes to complex 3D surface geometries. By self-assembling the bio-inks on pre-designed molds, physical patterns with diverse feature sizes ranging from cmto nm-level could be perfectly replicated onto the bio-labels surface (Figure 5a).…”

Interpol review of fingermarks and other body impressions (2019 – 2022)

“…Preliminary/Pilot studies – Several compounds to be applied in solution were proposed to detect fingermarks on various substrates, mostly non-porous: AIE-active molecules or complexes [ 230 , 245 , [379] , [380] , [381] , [382] , [383] , [384] , [385] , [386] , [387] , [388] ], benzothiazole derivatives [ 389 ], conjugated cationic polymers in solution [ 390 ], di-aqua tris(thenoyltrifluoroacetonate) europium III complex [ 391 ], dye-doped amphiphilic conjugated polymer micelles [ 392 ], dye-doped octasilsesquioxane hybrids [ 393 , 394 ], phenolic ligands chelated with metal ions [ 395 ], sequential processing involving the lifting of fingermarks by a cellulose membrane followed by immersion in water or chemical imaging [ 218 ], tetraphene derivatives [ 396 ]. Other reagents or mechanisms were also proposed: deposition of metallic films (i.e., copper, chromium, and aluminium) using magnetron sputtering [ 397 ], soot from camphor [ 398 ], sublimation of 9-fluorenone under vacuum [ 399 ].…”

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

“…The chemical residues present in the LFPs were normally very minimal (less than 10 μg) with an average thickness of about 0.1 μm. The LFPs were impressed on the surfaces, nearly 99% of the LFPs contain water 101 . As this water begins to evaporate quickly from the LFPs, subsequently the FPs dry.…”