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.