Multimode Anticounterfeiting Labels Based on a Flexible and Water-Resistant NaGdF₄Yb³⁺,Er³⁺@Carbon Dots Chiral Fluorescent Cellulose Film

Abstract

Advanced fluorescent anticounterfeiting technology has attracted a great deal of attention and inspired researchers to develop reliable fluorescent materials with multimodal luminescence. Herein, hydrophobic NaGdF4:Yb3+,Er3+ nanoparticles with dual-mode luminescence were prepared through a one-step solvothermal method using oleic acid as a chelating agent and octadecene as a solvent. The as-synthesized sample was found to provide both green upconversion luminescence and blue downconversion luminescence at excitation wavelengths of 365 and 980 nm. The structure and composition analysis showed that the as-obtained samples were spherical NaGdF4:Yb3+,Er3+@carbon dots (CDs) with a 14.5 ± 0.2 nm particle size and good dispersity in nonpolar solvents. Subsequently, NaGdF4:Yb3+,Er3+@CDs were coated on a cholesteric nanocellulose film with structural color to prepare multimode circularly polarized fluorescent materials. The prepared composite film is flexible and water-resistant, meaning that it is very suitable for anticounterfeiting labels, not only providing a simple and rapid synthesis method with which to prepare multimode fluorescent materials but also presenting a novel anticounterfeiting technology.

Circularly polarized organic room temperature phosphorescence activated by liquid crystalline polymer networks

“…Circularly polarized luminescent (CPL) materials with outstanding optical sensitivity and spatial resolution have promising applications in asymmetric catalysis, 1,2 data storage, 3,4 3D displays, 5,6 and optical encryption. [7][8][9] The performance of CPL materials is evaluated using dissymmetry (g lum ) values and photoluminescence quantum efficiency (PLQY). 4,[10][11][12][13] In recent years, different systems of CPL materials have been developed, such as organic crystals, 14,15 self-assembled systems, 16 metal complexes, 17 and polymers.…”

Polymer‐Based Circularly Polarized Luminescent Materials

“…Cellulose nanocrystals (CNCs), due to their intriguing hierarchical chirality, especially that derived from self-assembled cholesteric structures, are considered as powerful chiral nanomaterials to manufacture CPL-active platform. [43,[147][148][149][150][151][152][153] The hydroxyl and charged groups on the CNCs surface can form non-covalent bonds with achiral luminophores, such as organic luminophores, [16,149,[154][155][156][157] quantum dots, [158][159][160] carbon dots (CDs), [161][162][163][164][165] upconverting nanoparticles, [166] and so on. [167,168] The CPL performance of CNCs-based materials is summarized in Table 3.…”

“…[176] This strategy could achieve the generation of CPLactive polyfluorene aggregate by completely removing dialkylpolysilane. The authors found that the resulting heteroaggregates might be composed of one polyfluorene chain and two Fluorescent organic dyes Solid film -0.68 [16] Fluorescent organic dyes Solid film -0.28 [157] Polyacetylene Solid film -0.65 [155] Quinine sulfate Solid film 38% 0.58 [149] Quinine sulfate dihydrate Solid film -0.51 [154] PEI Solid film -0.025 [156] CdSe/CdS quantum rods Solid film -0.45 [148] ZnS/CdSe quantum dots Solid film -0.48 [158] ZnS/CdSe quantum dots Solid film -0.84 [159] Silicon quantum dots Solid film -0.25 [160] Carbon dots Solid film 30.22% 0.74 [161] Carbon dots Aqueous dispersions -0.2 [162] Carbon dots Solid film 5.2% 0.27 [163] Carbon dots Solid film 2.8% 0.66 [164] Carbon dots Solid film -1.47 [165] Upconverting nanoparticles Solid film -0.156 [166] Lanthanide complexes Solid film 66.7% 0.36 [167] Perovskite nanocrystals Solid film 43.1% 0.057 [168] Gold nanoclusters Solid film -0.287 [172] Silver nanoclusters Solid film 15.96% 0.12 [173] NaGdF4Yb 3+ , Er 3+ @ Carbon dots Solid film -0.84 [152] polysilanes chains. Wei et al described the preparation of polyether-based cholesteric liquid crystalline copolymers containing chiral cholesteryl, cross-linkable allyl, as well as, cyano-biphenyl mesogenic groups moieties by anionic ring-opening polymerization.…”

Upcycling waste expanded polystyrene into UV-excited dual-mode multicolor luminescent electrospun fiber membranes for advanced anti-counterfeiting

“…Growing efforts have been devoted to developing dual-mode luminescent materials to satisfy high-level anti-counterfeiting requirements. [53][54][55][56][57][58][59][60] Although these dual-mode luminescent materials reported in the literature have better anti-counterfeiting security than traditional single-mode luminescent materials, most of them need NIR light sources as excitation sources. [53][54][55][56][57] Relative to NIR light sources, UV light sources are cost-effective, commercially readily available and easy to operate (especially hand-held 254 nm and 365 nm UV lamps).…”

“…[53][54][55][56][57][58][59][60] Although these dual-mode luminescent materials reported in the literature have better anti-counterfeiting security than traditional single-mode luminescent materials, most of them need NIR light sources as excitation sources. [53][54][55][56][57] Relative to NIR light sources, UV light sources are cost-effective, commercially readily available and easy to operate (especially hand-held 254 nm and 365 nm UV lamps). 58,59 Accordingly, designing UV-excited dual-mode luminescent materials that only need UV excitation light sources would be more promising in practical anti-counterfeiting applications.…”