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Near-infrared Laser Triggered Full-Color Tuning Photon Upconversion and Intense White Emission in Single Gd2O3 Microparticle
摘要： Full-color emission fluorescence materials are of imperious demands in information storage, graphics imaging and anti-counterfeiting fields. However, it is still a formidable challenge to develop a single material with full-color emission and high purity white output under a NIR-light excitation. Herein, we design a novel and convenient strategy to tune the upconversion luminescence color with full color range in lanthanide ions doped Gd2O3 microspheres via a single NIR laser sensitization. Different from the typical ion-dependent tuning of color, the bright and flexible full-color emission tuning from blue to cyan, green, yellow, pink, and red can be controllable implementation in a single microparticle. Particularity, benefiting from the laser sensitive color adjustment, highly intense white color emission can be simultaneously achieved in diverse doped ion concentration particles. In addition, the upconversion emission intensity has been evidently improved if using a NIR laser sensitization, leading to significantly enhanced upconversion red luminescence signal (44-fold) at the power 446 mW. The mechanistic investigations and dynamics analysis reveal that the unprecedented color tunability from these microcrystals is attributed to dynamic control of multi-energy transfer and multi-cross relaxation process. Furthermore, owning to their excellent upconversion luminescence properties, Gd2O3 microparticles could be used to the anticounterfeiting application in different colors. These findings not only open a way to fabricate a single material to fine tuning upconversion emission in a full color gamut, but also give the possibility to construction of the multicolor imaging for anti-counterfeiting applications.
关键词： upconversion luminescence,anti-counterfeiting,full color emission,lanthanide ions doped Gd2O3 microspheres,white color emission,laser sensitization
更新于2025-09-16 10:30:52
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Ethylene glycol-assisted ultrafast synthesis and luminescent properties of novel multifunctional EuSr2F7 and TbSr2F7 nanostructures for WLEDs, displays and anti-counterfeiting
摘要： In this paper, novel EuSr2F7 and TbSr2F7 nanostructures were successfully prepared via an ultrafast wet-chemical route at room temperature. The elemental compositions, morphology, luminescent behaviors, thermal stability, decay curves and quantum yield of the as-prepared samples were investigated. The fabricated white light-emitting diodes (WLEDs) devices exhibited excellent CRI and CCT values. The security inks and soft polydimethylsiloxane films were prepared for potential anti-counterfeiting and flexible display applications. Eventually, under low accelerating voltage and filament current, the as-prepared samples showed strong cathodoluminescence emission intensity. The above results suggest that the novel EuSr2F7 and TbSr2F7 nanostructures with outstanding luminescent performances could be promising for field-emission displays (FEDs), WLEDs, flexible display films, and anti-counterfeiting applications.
关键词： nanostructures,FEDs,anti-counterfeiting,WLEDs,flexible display films
更新于2025-09-12 10:27:22
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Self-assembly of coordination polymers on plasmonic surfaces for computer vision decodable, unclonable and colorful security labels
摘要： Incorporating security labels with physical unclonable functions (PUFs) into products is considered as the most effective anti-counterfeiting measure. Here we reported a PUF-based security label composed of random colorful patterns. The security label was fabricated through self-assembly of coordination polymers – a cupric bromide complex of pyrazine 1,4-dioxide – on lithographically defined plasmonic surfaces. The coordination polymer exhibits excitation wavelength dependent fluorescence fingerprints, which enables encoding spectral information in the polymer. The fluorescence peaks of each spectrum can be easily converted to a unique anti-counterfeiting barcode. The developed security label also carries 2D graphical information, which can be visualized under bright-field, dark-field and fluorescence multifunctional microscopy. It is multi-colored with high contrast under the bright/dark-field modes and single color under fluorescence mode. The multicolors originate from polymer-thickness dependent optical interference. The encryption with colors on a 50 lm square produces a minimum of 3739 PUF codes for the realized authentication system. Moreover, we developed a convenient and reliable authentication strategy based on the computer vision technique to verify the colorful PUF patterns with different definition, rotation angles, brightness, magnification and a mixture of these factors. A high correct validation rate of 100% is achieved using a match threshold of 0.3.
关键词： anti-counterfeiting,coordination polymers,plasmonic surfaces,security labels,physical unclonable functions,computer vision
更新于2025-09-12 10:27:22
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Sonochemical Synthesis of Carbon Dots/Lanthanoid MOFs Hybrids for White Light-Emitting Diodes with High Color Rendering
摘要： Although lanthanoid metal-organic frameworks (Ln-MOFs) have been widely developed for white light-emitting diodes (WLEDs), the color rendering index (CRI) values are still lower than 80. To overcome this limitation, a series of carbon dots/Ln-MOFs hybrids namely CDs-2@Ln-MOF, CDs-3@Ln-MOF and CDs-4@Ln-MOF containing blue emitting CDs and yellow emitting bimetallic [(Eu1.22Tb0.78(1,4-phda)3(H2O)](H2O)2 were prepared via sonication at room temperature to restrict the self-quenching of CDs in composite materials. The as-synthesized composite materials were investigated by FT-IR, PXRD, TEM, SEM and photoluminescence. The luminescent color of the materials can be adjusted by varying the amount of CDs and excitation wavelengths. The resulting CDs-3@Ln-MOF achieved excellent CRI up to 93 with the ideal CIE coordinate (0.334, 0.334) and appropriate correlated color temperature, CCT (5443 K). In addition, the tunable multi-colored luminescence based on single and bimetallic EuxTb2-x(1,4-phda)3(H2O)](H2O)2; x = 0, 0.73, 1.22, 1.57, 1.94 and 2 were applied as the luminescent security inks for anti-counterfeiting application through encoding/decoding and rewritable data.
关键词： anti-counterfeiting,luminescence material,white light-emitting diodes,metal-organic frameworks,carbon dots
更新于2025-09-11 14:15:04
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[ASME ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - Quebec City, Quebec, Canada (Sunday 26 August 2018)] Volume 1B: 38th Computers and Information in Engineering Conference - Optical PUF Design for Anti-Counterfeiting in Manufacturing of Metallic Goods
摘要： In the context of globalized supply chains, counterfeiting of manufactured goods is a growing problem. The financial, legal, and reputational costs that counterfeit goods impose on legitimate enterprises have spurred investigation into efficient and robust anti-counterfeiting methodologies. In particular, physically unclonable functions (PUFs) have been applied effectively in several manufacturing areas, especially electronics. However, anti-counterfeiting solutions for generic manufactured goods are often expensive to make and implement, or not robust to minor damage that the goods may sustain during transport and use. In this paper, a framework for developing robust, efficient, and cost-effective optical PUFs for anti-counterfeiting of manufactured metallic goods is proposed, along with an example implementation for 4140-steel parts according to standard ASTM A29. For an input library of 50 steel micrographs, the proposed example PUF is shown to have good robustness to simulated part damage and an estimated classification error rate of less than 1%.
关键词： optical PUFs,physically unclonable functions,anti-counterfeiting,counterfeiting,manufactured goods,ASTM A29,4140-steel
更新于2025-09-09 09:28:46
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Facile Synthesis and Controllable Emission of Tm <sup>3+</sup> /Er <sup>3+</sup> -Doped and -Co-doped α-NaYbF <sub/>4</sub> Upconversion Nanocrystals
摘要： Tm3+, Er3+-doped and -co-doped α-NaYbF4 nanoparticles were synthesized via a facile hydrothermal route with oleic acid as the capping agent. Experimental results showed that the doped NaYbF4 nanoparticles possessed a cubic phase with the average size of ～13 nm. Upon excitation by a 980 nm laser, the as-synthesized nanoparticles exhibited blue and red upconversion emissions corresponding to the monodoped Tm3+, Er3+ in the cubic-phase NaYbF4, respectively, and intense green and red emissions in the Tm3+/Er3+-co-doped NaYbF4 nanoparticles. Furthermore, the possible energy transfer mechanism among Yb3+/Tm3+/Er3+ in α-NaYbF4 nanoparticles was also proposed. The cell toxicity test revealed that the as-synthesized upconversion nanoparticles possessed remarkably low cytotoxicity. All of the advantageous features including facile synthesis, controllable emission, and low cytotoxicity make the upconversion nanoparticles promising for multicolor bioimaging and anti-counterfeiting applications.
关键词： anti-counterfeiting applications,multicolor bioimaging,upconversion nanocrystals,hydrothermal synthesis,energy transfer mechanism,α-NaYbF4,low cytotoxicity,Tm3+/Er3+-doped
更新于2025-09-04 15:30:14