Photoluminescent Composites of Lanthanide-Based Nanocrystal-Functionalized Cellulose Fibers for Anticounterfeiting Applications

Abstract

Photoluminescent materials have been applied worldwide in anticounterfeiting and security fields due to their unique performance of better security, easy identification, and difficulty of duplication. Herein, a facile, green, and low-cost strategy to fabricate biomass-based composites composed of lanthanide rare earth ions-doped nanocrystals and cellulose fibers for anticounterfeiting application was presented. The photoluminescent materials were prepared via in situ chemical deposition of rare earth ions onto bleached hardwood pulp cellulose fibers (bhp­Fibers) surface using polyvinyl­pyrrolidone (PVP) as coupling agent, forming bhpFibers-PVP@­LaF3:Eu3+ composites. The bhp­Fibers-PVP@­LaF3:Eu3+ composites showed excellent luminescence, and their fluorescence intensity can be simply controlled by varying the addition of the right amount of lanthanum (La3+) and europium (Eu3+) ions in aqueous medium. Furthermore, the composites have been used as blocks to form photoluminescence paper via a suction filtration procedure. The as-prepared paper possessed excellent luminescence, high flexibility, well writable and printable properties. Moreover, the whole procedure was carried out in a mild environment without toxic reagents. This simple, green, and low-cost technology presented has advantages of wholesale production of biomass-based photoluminescent materials for anticounterfeiting applications.

Stimuli‐Responsive Naphthalene Diimide as Invisible Ink: A Rewritable Fluorescent Platform for Anti‐Counterfeiting

“…Variety of paper materials were collected from IASST-Guwahati. 1 H and 13 C spectra were recorded on a Bruker Ultrashield 300 MHz spectrometer. FT-IR spectra were obtained from a Perkin Elmer, Spectrum two-102083 spectrophotometer.…”

“…After completion of reaction, the mixture was allowed to cool, dried under vacuum to obtain the product as beige colour solid. ISO_NDI: Yield: (0.66 g, 70%), 1…”

“…Counterfeiting of items especially banknotes, legal documents, certificates, electronics component, branded and pharmaceuticals products have become an important issue for industry as well as for governments. [1][2][3] Illegal counterfeiting activities particularly for currency notes has lead to the economic fallout. [4,5] Furthermore counterfeited pharmaceutical products put the patient's health in jeopardy as they may contain unidentified contents with incorrect specifications.…”

“…Counterfeiting/forging is a worldwide concern that originates negative impacts on the socio‐economic as well as posing serious security threats to the whole nation. Counterfeiting of items especially banknotes, legal documents, certificates, electronics component, branded and pharmaceuticals products have become an important issue for industry as well as for governments . Illegal counterfeiting activities particularly for currency notes has lead to the economic fallout .…”

Luminescent Cellulose Fibers Modified with Poly((9-Carbazolyl)Methylthiirane)

“…The luminescent fibers obtained with this method can find an application as an anti-counterfeiting agent. There is a wide range such fibers that have been developed and used as luminescent additives to the paper products [ 20 , 21 ]. Security fibers can be obtained by melt spinning, diffusion or direct dying [ 22 ].…”