Thieno[3,4‐c][1,2,5]Thiadiazole‐Based Organic Conjugated Molecules with Visible and Near‐Infrared Dual Emissions for Luminescent Anti‐Counterfeiting Applications

Abstract

Luminescence materials have gained extensive attention in anti-counterfeiting owing to their unique superiorities. Visible-near infrared (vis-NIR) dual emission that combines naked-eye visible light and concealed NIR light would provide a promising strategy for improving the covertness and secure anti-counterfeiting effect. Here, two organic conjugated materials 4,4′-(thieno[3,4-c][1,2,5] thiadiazole-4,6 diyl)bis(N,N-bis(4-(aldehyde)phenyl)aniline) (TTD-TPA-CHO) and 4,4′-(thieno[3,4-c][1,2,5]thiadiazole-4,6 diyl)bis(N,N-bis(phenyl)aniline) (TTD-TPA) based on thieno[3,4-c][1,2,5]thiadiazole (TT) have been developed, exhibiting vis-NIR dual emissions by manipulating the charge transfer states. With the aid of self-healing technique, stretchable and highly transparent TTD-TPA-CHO and TTD-TPA containing self-healing PDMS films are efficiently prepared to fabricate dual-mode anti-counterfeiting patterns for demonstrating the anti-counterfeiting applications. Under UV light, the luminescent patterns in visible region can be read out by the naked eye, while the concealed information could be accessed by NIR detection devices. These results evidently suggest the important role of vis-NIR dual emission in enhancing the stealth of encrypted information and the security level of anti-counterfeiting. Hopefully, this work would promote the further development of vis-NIR dual-emission organic conjugated materials in anti-counterfeiting techniques.

Recent Development of Photochromic Polymer Systems: Mechanism, Materials, and Applications

“…(D) Photoisomerization of DTEDBA and Cu-DTEDB. Reproduced with permission from [ 105 ]. Copyright 2016, John Wiley & Sons Inc. (E) Reversible bending of a crystalline rod.…”

“…Li et al. [ 105 ] doped diphenyl ethylene into an infinite coordination polymer, Cu-DTEDBA, to obtain a photochromic polymer. The light green Cu-DTEDBA powder turned dark blue within 5 min of UV irradiation and recovered within 30 min of visible light irradiation, and this behavior was attributed to the reversible photoisomerization of diphenyl ethylene.…”

Functional PDMS Elastomers: Bulk Composites, Surface Engineering, and Precision Fabrication

“…PDMS is optically transparent at 240–1100 nm and can serve as a flexible substrate or carrier for various light‐absorbing and luminescent materials, allowing the fillers to define the optical properties of the composite. These composites have demonstrated practical applications within the areas of smart displays, [ 79 ] camouflage, [ 80 ] anti‐counterfeiting, [ 81 ] wearable light‐emitting devices, [ 82 ] and various sensors. [ 83 ] For example, the surface plasmonic resonance of metal nanoparticles with controllable size can generate precisely tunable absorption characteristics.…”

Electron‐Withdrawing Substituents Allow Boosted NIR‐II Fluorescence in J‐Type Aggregates for Bioimaging and Information Encryption

“…[20] Smart luminescent materials with visible-NIR dual emissions are promising for improving secure anti-counterfeiting effect due to the combination of naked-eye visible light and concealed NIR ligh. [21] Because NOBDP-NO 2 features visible and NIR-II dual emissions by controlling molecular self-assembly, we further investigated its potential applications in information encryption and storage. As depicted in Figure 6A, NOBDP-NO 2 in THF showed intense visible emission at 675 nm when excited with 365 nm light.…”