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A series of long-afterglow luminescent materials (SrAl2O4: Eu2+ (SAOE), SrAl2O4: Eu2+, Dy3+ (SAOED) and SrAl2O4: Eu2+, Dy3+, Gd3+ (SAOEDG)) was synthesized via the combustion method. Temperature and concentration control experiments were conducted on these materials to determine the optimal reaction temperature and ion doping concentration for each sample. The crystal structure and luminescent properties were analyzed via X-ray diffraction (XRD), photoluminescence (PL), and afterglow attenuation curves. The outcomes demonstrate that the kind of crystal structure and the location of the emission peak were unaffected by the addition of ions. The addition of Eu2+ to the matrix’s lattice caused a broad green emission with a central wavelength of 508 nm, which was attributed to the characteristic 4f65d1 to 4f7 electronic dipole, which allowed the transition of Eu2+ ions. While acting as sensitizers, Dy3+ and Gd3+ could produce holes to create a trap energy level, which served as an electron trap center to catch some of the electrons produced by the excitation of Eu2+ but did not itself emit light. After excitation ceased, this allowed them to gently transition to the ground state to produce long-afterglow luminescence. It was observed that with the addition of sensitizer ions, the luminous intensity of the sample increased, and the afterglow duration lengthened. The elemental structure and valence states of the doped ions were determined with an X-ray photoelectron spectrometer (XPS). Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to characterize the samples. The results show that the sample was synthesized successfully, and the type and content of ions in the fluorescent powder could be determined. The fluorescence lifetime, quantum yield, bandgap value, afterglow decay time, and coordinate position in the coherent infrared energy (CIE) diagram of the three best sample groups were then analyzed and compared. Combining the prepared phosphor with ink provides a new idea and method for the field of anti-counterfeiting through screen printing.

Stimuli-responsive luminescent materials have received great attention for their potential application in anti-counterfeiting and information encryption. Manganese halide hybrids have been considered an efficient stimuli-responsive luminescent material due to their low price and adjustable photoluminescence (PL). However, the photoluminescence quantum yield (PLQY) of PEA2MnBr4 is relatively low. Herein, Zn2+- and Pb2+-doped PEA2MnBr4 samples are synthesized, and show an intense green emission and orange emission, respectively. After doping with Zn2+, the PLQY of PEA2MnBr4 is elevated from 9% to 40%. We have found that green emitting Zn2+-doped PEA2MnBr4 could transform to a pink color after being exposed to air for several seconds and the reversible transformation from pink to green was achieved by using heating treatment. Benefiting from this property, an anti-counterfeiting label is fabricated, which exhibits excellent “pink-green-pink” cycle capability. Pb2+-doped PEA2Mn0.88Zn0.12Br4 is acquired by cation exchange reaction, which shows intense orange emission with a high QY of 85%. The PL of Pb2+-doped PEA2Mn0.88Zn0.12Br4 decreases with increasing temperature. Hence, the encrypted multilayer composite film is fabricated relying on the different thermal responses of Zn2+- and Pb2+-doped PEA2MnBr4, whereby the encrypted information can be read out by thermal treatment.

Here, a simple one-step hydrothermal-assisted carbonization process was adopted for the preparation of nitrogen/phosphorous-doped carbon dots from a water-soluble polymer, poly 2-(methacryloyloxy)ethyl phosphorylcholine (PMPC). By the free-radical polymerization method, PMPC was synthesized using 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and 4,4′-azobis (4-cyanovaleric acid). The water-soluble polymers, PMPC, that have nitrogen/phosphorus moieties are used to prepare carbon dots (P-CDs). The resulting P-CDs were thoroughly characterized by various analytical techniques such as field emission-scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDS), high-resolution transmittance electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) spectroscopy and fluorescence spectroscopy to determine their structural and optical properties. The synthesized P-CDs displayed bright/durable fluorescence, were stable for long periods, and confirmed the enrichment of functionalities including oxygen, phosphorus, and nitrogen heteroatoms in the carbon matrix. Since the synthesized P-CDs showed bright fluorescence with excellent photostability, excitation-dependent fluorescence emission, and excellent quantum yield (23%), it has been explored as a fluorescent (security) ink for drawing and writing (anti-counterfeiting). Further, cytotoxicity study results advised for biocompatibility and thus were used for cellular multicolor imaging in nematodes. This work not only demonstrated the preparation of CDs from polymers that can be used as advanced fluorescence ink, a bioimaging agent for anti-counterfeiting, and cellular multicolor imaging candidate, but additionally prominently opened a new perspective on the bulk preparation of CDs simply and efficiently for various applications.

The property of persistent luminescence shows great potential for anti-counterfeiting technology and imaging by taking advantage of a background-free signal. Current anti-counterfeiting technologies face the challenge of low security and the inconvenience of being limited to visible light emission, as emitters in the NIR optical windows are required for such applications. Here, we report the preparation of a series of Zn1+xGa2−2xSnxO4 nanoparticles (ZGSO NPs) with persistent luminescence in the first and second near-infrared window to overcome these challenges. ZGSO NPs, doped with transition-metal (Cr3+ and/or Ni2+) and in some cases co-doped with rare-earth (Er3+) ions, were successfully prepared using an improved solid-state method with a subsequent milling process to reach sub-200 nm size particles. X-ray diffraction and absorption spectroscopy were used for the analysis of the structure and local crystal field around the dopant ions at different Sn4+/Ga3+ ratios. The size of the NPs was ~150 nm, measured by DLS. Doped ZGSO NPs exhibited intense photoluminescence in the range from red, NIR-I to NIR-II, and even NIR-III, under UV radiation, and showed persistent luminescence at 700 nm (NIR-I) and 1300 nm (NIR-II) after excitation removal. Hence, these NPs were evaluated for multi-level anti-counterfeiting technology.

Binder jetting (BJT) is a powder bed based additive manufacturing (AM) process where the interaction of inkjetted droplets of a binder and particles in the powder bed create 3D geometries in a layerwise fashion. The fabricated green parts are usually thermally post-processed for densification and strengthening. BJT holds distinct advantages over other AM processes as it can fabricate parts with virtually any materials (metals, ceramics, and polymers) in a fast and cost-effective way, while achieving isotropic material properties in the parts. However, broad adoption of this process for production is still lagging, partially due to the lack of repeatable part quality, which largely stems from the limited understanding of the process physics, namely binder-powder (B/P) interaction. To bridge this knowledge gap, it is necessary to understand the implications of B/P interaction on process-structure-property relationships and discover ways to achieve new functionalities for enhanced properties. Thus, this research is broadly focused in establishing understanding in (i) binder-powder interaction and (ii) the impact of binder on part densification. Prior studies have focused on the effects of powder interaction with micro/meso-scale binder droplets, despite commercial BJT systems featuring picoliter-scale droplets. These studies have explored the effects of B/P interaction on printed primitive formation, but it's implication on final part properties have not been studied. In this work, the effects of particle size distribution and droplet size variation on final part properties are explored. Additionally, the effects of B/P interaction on accuracy and the resolution of the printed parts are investigated. Densification of parts is a primary focus of many BJT studies as it dictates the final part properties and is influenced by factors from both the printing process and post-processing treatments. Binder plays an integral role in the shaping of parts and maintaining part integrity until densification through sintering. Prior studies on the effects of binder content on densification are inclusive. In this work, a new approach termed as "shell printing" is introduced to vary the binder content in the parts. The process-structure-properties influenced by this approach are investigated. It was found that binder hinders densification, and through the selective variation of binder content throughout the part volume, this new approach is introduced as a means for enhancing part properties. Finally, the insights from the impact of binder on densification are leveraged to create an anti-counterfeiting tagging strategy by controlling the pores and grain microstructures inside a part. In this novel approach, binder concentration is controlled in a manner that the stochastically formed pores are clustered to create a designed domain that represents a secret 'tag' within the part volume. The created tagging domains, and the feature resolvability of this approach are investigated through metallographic characterization and non-destructively evaluated through micro-computed tomography. Doctor of Philosophy Binder jetting (BJT) is an additive manufacturing (AM) process to create 3D geometries from powder particles. Liquid droplets of binder from an inkjet printhead are jetted on a bed of packed powders, binding the particles. The as-printed parts, known as green parts, are generally fragile and require thermal post-processing (through sintering) for densification and strengthening. BJT holds distinct advantages over other AM processes as it can fabricate parts with virtually any powdered materials (metals, ceramics, and polymers) in a fast and cost-effective way. However, broad adoption of this process for production is still lagging, partially due to the lack of repeatable part quality, which largely stems from the limited understanding of the process physics, namely binder-powder (B/P) interaction. In this study the implications of B/P interaction on part quality (e.g., density, strength) and dimensional accuracy are studied. Additionally, the impact of binder on sintering densification is studied. Specifically, the effects of varying amount of binder on sintered part density, strength and internal pore and grain microstructures are empirically investigated. Finally, a novel anti-counterfeiting method for BJT printed parts is introduced based on the insights gained from the study of the impact of binder on densification. Through control over binder placement throughout the part, porous regions can be generated selectively throughout the part volume, which can be detected through x-ray computed tomography. Overall, an improved understanding of BJT processing conditions is achieved through this research, which can guide future designers to fabricate BJT parts with enhanced part properties and functionality.

Developing a secure anti-counterfeiting technology with more dimensional encryptions is urgently demanded. The lead-free double perovskite (DP) family represented by A2BIBIIIX6 hold great potential for applications in advanced fluorescence anti-counterfeiting owing to of large-bandgap engineering via BI/BIII site transmutation or exotic dopants. Herein, Ln3+ (Ln3+ = Eu3+, Ho3+, and Yb3+)-doped Cs2Ag0.3Na0.7InCl6 DP microcrystals (MCs) were firstly successfully synthesized by a hydrothermal method. By selective excitation of different luminescence centrals through precise control of excitation wavelength, we demonstrate dynamic color tuning in the Ln3+-doped Cs2Ag0.3Na0.7InCl6 DPMCs. Specifically, under various excitations of UV 300, 394, and NIR 980 nm, the as-synthesized DPMCs display triple emissions of warm yellow, red, and green, respectively. The warm yellow light stems from the self-trapped exciton (STE) downconversion (DC) luminescence of the DP matrix, while the red and green lights can be attributed to the strong Eu3+ 5D0→7FJ (J = 1, 2, 3, 4) DC luminescence and Ho3+ (5F4→5I8) upconversion (UC) luminescence sensitized by Yb3+. Thus, the as-synthesized Ln3+-doped Cs2Ag0.3Na0.7InCl6 DPMCs, which possess tunable combined DC/UC luminescence, show great potential to be an anti-counterfeiting material with a high security level.

Developing radical emission at ambient conditions is a challenging task since radical species are unstable in air. In the present work, we overcome this challenge by coassembling a series of tricarbonyl-substituted benzene molecules with polyvinyl alcohol (PVA). The strong hydrogen bonds between the guest dopants and the PVA host matrix protect the free radicals of carbonyl compounds after light irradiation, leading to strong solid state free radical emission. Changing temperature and peripheral functional groups of the tricarbonyl-substituted benzenes can influence the intensity of the radical emission. Quantum-chemical calculations predict that such free radical fluorescence originates from anti-Kasha D2 →D0 vertical emission by the anion radicals. The photoinduced radical emission by the tricarbonyl-substituted benzenes was successfully utilized for information encryption application. Ministry of Education (MOE) This research was sponsored by the Shanghai Pujiang Program of China (No.20PJ1400500) and the Singapore Academic Research Fund (No.RT12/19 and MOE-T2EP10120-0003). G.B. thanks the support by the Swedish Research Council (No.2020-04600). The computations were enabled by the Swedish National Infrastructure for Computing (SNIC)at the High Performance Computing Center North (HPC2N) partially funded by the Swedish Research Council through grant agreement no. 2018-05973

Security inks are used in areas such as money, expensive products, identity cards, passports. Generally, they are more expensive than conventional inks. A good security ink is expected to be fairly inexpensive and non-replicable. Pigments used in security ink are usually produced from rare earth elements. It is very difficult to produce ink from rare earth elements and high performance ink carrier systems are needed. There is no need for special carrier systems to produce ink from organic fluorescent pigments, and they allow cheaper ink production while reducing reproducibility. In this study, it is aimed to produce ink using organic-based fluorescent pigment. For this purpose, solvent-based ink formulations containing commercial solvent based organic fluorescent blue pigment in different ratios were prepared with polyurethane resin. The prepared inks were printed on the paper surface with the inkjet printing system. The colour properties of the prints obtained were determined under daylight and UV light. In addition, the gloss, adhesion, abrasion resistance, light fastness and drying times of the prints were determined. As a result, it has been determined that the ink produced is transparent in daylight, has a blue glow in UV light and can be used as a security ink in valuable documents.

A microfluidic platform for continuous synthesis of hydrogel microparticles with superparamagnetic colloids (SPCs) embedded at prescribed positions is described. The shape of the cross-linked microparticle is independently controlled by stop-flow lithography, whereas the position of trapped SPCs are dictated by virtual magnetic moulds made of 2D nickel patches facilitating magnetic trapping. The spatial positions of trapped SPCs collectively function as a binary code matrix for product authentication. Analytical and finite element methods are combined to optimize the trapping efficiency of SPCs by systematically investigating magnetic field microgradients produced by nickel patches. It is envisioned that the proposed magnetic microparticles will contribute to the development of soft matter inspired product quality control, tracking and anti-counterfeiting technologies., Advanced Materials Interfaces, 9 (29), ISSN:2196-7350

The development of high-level anti-counterfeiting techniques is of great significance in economics and security issues. However, intricate reading methods are required to obtain multi-level information stored in different colors, which greatly limits the application of anti-counterfeiting technology on solving real world problems. Herein, we realize multicolor information anti-counterfeiting under simply external stimulation by utilizing the functional groups and multiple emission centers of lanthanide metal organic framework (Ln-MOFs) to tune luminescence color. Water responsive multicolor luminescence represented by both the tunable color from red to blue within the visible region and high sensitive responsivity has been achieved, owing to the increased nonradiative decay pathways and enhanced Eu3+-to-ligand energy back transfer. Remarkably, information hidden in different colors needs to be read with a specific water content, which can be used as an encryption key to ensure the security of the information for high-level anti-counterfeiting.

Herein, we first designed a one‐step strategy to achieve matrix‐free room temperature phosphorescence (RTP) materials by low temperature solid phase synthesis, using sodium citrate as carbon source and urea as nitrogen source. The NaF, NaCl, NaBr, and NaI were chosen as the inducer source of halogens to effective trigger the RTP emission from graphitic carbon nitride quantum dots (CNQDs) denoted F‐CNQDs, Cl‐CNQDs, Br‐CNQDs and I‐CNQDs. All the doped‐CNQDs emitted bright fluorescence upon 365 nm irradiation. After the 365 nm UV lamp is off, only the Br‐CNQDs showed green phosphorescence which can be observed by naked eye. The phosphorescence emission of Br‐CNQDs is excitation‐dependent from 510 to 610 nm with the average RTP lifetime of 70 milliseconds, which indicated Br‐CNQDs could exhibit color‐tunable phosphorescence. When 365 nm UV is off, Br‐CNQDs emitted green afterglow for about 3 seconds observed naked eye, while the Br‐CNQDs presented visible yellow afterglow for about 3 seconds with ceasing off 395 nm irradiation. The absolute phosphorescence quantum yield (PQY) of the Br‐CNQDs powder reaches up to 3.64%. Thus, the color change and long lifetime of phosphorescence from the excitation‐dependent feature could provide a security application for counterfeiting and information protection systems.

Orange-red emitting praseodymium (Pr3+) activated yttrium molybdenum oxide (Y2MoO6) nanophosphors (NPs) were synthesized via low-temperature solution combustion method using Aloe vera gel as a surfactant and fuel. The synthesized NPs were subjected to structural, morphological, optical, and electrical studies. The powder X-ray diffraction (PXRD) study reveals that the Y2MoO6 composite consists of a monoclinic crystal phase. Peak shift to the left side was observed with increase in the doping concentration of Pr3+ ions into the crystal system, which is attributed to the strain. Foamy type morphology was revealed from scanning electron microscope studies, whereas the nanostructural features of the samples were confirmed by both transmission electron microscope and PXRD. From the diffused reflectance spectroscopy study, the optical band gap was estimated to be in the range of 3.36–3.48 eV. Fourier transforms infrared spectroscopy was used to identify the metal oxygen bonds along with the other types of bonds if any. The AC conductivity and dielectric properties were measured in the frequency range of 100 Hz–5 MHz. The photoluminescence (PL) studies revealed the characteristic of emission peaks of Pr3+ ions. The Commission International de l'Eclairage (CIE) coordinates were located in orange-red color. The average correlated color temperature analysis indicates that the Y2MoO6:Pr3+ NPs can be useful for use in warm light sources. The Y2MoO6: Pr3+ (5 mol%) NPs were used for the design of anti-counterfeiting ink in security applications. The tunable properties of the prepared Y2MoO6:Pr3+ NPs make them suitable for multifunctional applications.

© 2022 Wiley-VCH GmbH.The demand for encoded surfaces has increased significantly over the past decade driven by the rapid digitalization of the world. Surface-enhanced Raman scattering (SERS) offers unique capabilities in generation of encoded surfaces. The challenge is the limited versatility of SERS-based encoding systems in terms of the applicable surfaces. This study addresses this challenge by using a temporary tattoo approach together with simplified fabrication of SERS-active patterns by ink-jet printing of a particle-free reactive silver ink. Plasmonic silver nanostructures form on the tattoo paper upon ink-jet printing and a brief thermal annealing. The SERS activity is sufficient to detect taggant molecules of rhodamine 6G, methylene blue, and rhodamine B with a nanomolar level sensitivity. Raman-active taggants can be incorporated into the ink, for drop-on-demand patterning of multiple molecules in 1D and 2D barcode geometries. The SERS barcodes can be effectively transferred to a range of different substrates retaining high plasmonic activity and geometric integrity. The presented approach decouples the SERS-active pattern preparation from the final substrate and greatly improves the versatility of the barcodes.

The turn-off fluorescent photoswitches for information encryption are constantly being developed. However, there are no reports about time-switchable (fluorescence lifetime-switchable) encryption to overcome the limitations of tunable encoding numbers in spectrally and temporally encoded libraries. Based on the double-exponential fitting of fluorescence lifetime, we propose, a fatigue-free and highly flexible switch between the amplitude-weighted average fluorescence lifetime (τm) and the intensity-weighted average fluorescence lifetime (τi), which will realize the supermultiplexed fluorescence lifetime switchable encryption. The potentially enormous library of different fluorescent lifetime combinations would facilitate the development of information security.

In this study, we utilized a simple and efficient microwave heating method with polyethyleneimine (PEI) and phosphate as raw materials to synthesize room temperature persistent luminescence (RTPL) materials that emit phosphorescent light for up to 10 s. Our investigation revealed that the optimal synthesis conditions were a microwave radiation power of 560 W and a heating time of 5 min. The synthesized RTPL materials had an average particle size of 2 nm and exhibited excellent RTPL performance, with optimal excitation and emission wavelengths of 360 nm and 544 nm, respectively. Additionally, these materials displayed good water solubility. We conducted mapping experiments and in situ phosphorescent imaging of plants to showcase the potential applications of RTPL materials in the fields of biological imaging and anti-counterfeiting. Overall, our findings demonstrate the promising potential of these RTPL materials as versatile tools for various practical applications.

This paper describes the opportunities that blockchain technology applied to product traceability might offer to firms of Made in Italy against counterfeiting of their products, and the challenges to the adoption of blockchain technology in these firms, especially SMEs. The focus is on the Italian Region Marche which is characterised by a prevalence of firms specialised in the Made in Italy. The paper proposes a triple helix approach to facilitate the diffusion of blockchain technology in the Marche Region and individuates policies and non-academic actors at the regional level that could help SMEs to know and adopt this innovative technology.

Sometimes fingerprint-like features are found in a material. The exciting discovery poses new challenges on how to use the features to build an object authentication protocol that could tell customers and retailers equipped with a mobile device whether a good is authentic or fake. We are exactly in this situation with Cholesteric Spherical Reflectors (CSRs), tiny spheres of liquid crystals with which we can tag or coat objects. They are being proposed as a potential game-changer material in anti-counterfeiting due to their unique optical properties. In addition to the problem of processing images and extracting the minutiæ embedded in a CSR, one major challenge is designing cryptographically secure authentication protocols. The authentication procedure has to handle unstable input data; it has to measure the distance between some reference data stored at enrollment and noisy input provided at authentication. We propose a cryptographic authentication protocol that solves the problem, and that is secure against semi-honest and malicious adversaries. We prove that our design ensures data privacy even if enrolled data are leaked and even if servers and provers are actively curious. We implement and benchmark the protocol in Python using the Microsoft SEAL library through its Python wrapper PySEAL.

International audience; Smart emissive materials that can react to external stimuli in a reversible way are challenging to develop and have been the subject of considerable interest. Here, we present a printable hybrid material that can withstand numerous writing-erasing cycles. This material is based on a poly(methyl methacrylate) host matrix embedding by copolymerization of a red NIR phosphorescent metal cluster and a blue green 3-oxindole emitter. Irradiation of the homogeneous and stable hybrid films changes the emission color from white to deep red because of the oxygen perturbed energy transfer from the organic dye to the metal cluster. Because of the low PMMA gas permeability, encrypted data lifetime can be tuned from minutes to days, can be self-erased, and be rewritten at will. This material represents a key stepping stone for anticounterfeiting, optoelectronic, data recording, and many other technologies © 2019 Elsevier Ltd

To prevent counterfeiting, a lot of advanced security technologies have been developed, including luminescent printing. Therefore, the pigments with advanced security features are urgently pursued for luminescence printing-based anti-counterfeiting technology. Here, micron-sized spheres of hexagonal-structured and color-tunable emitting (Y, Tb, Eu, Bi)BO3 have been rapidly synthesized by microwave processing, followed by a proper annealing. Incorporation of Bi3+ greatly enhances the emission intensity of Eu3+ and of Tb3+. Under the excitation at 260 nm, the spheres exhibit UV emission at 330 nm (3P1→1S0 transition of Bi3+), green emission at 546 nm (5D4→7F5 transition of Tb3+) and orange-red emission at 592 nm (5D0→7F1 transition of Eu3+), mainly due to the three energy transfer processes of Bi3+→Tb3+, Bi3+→Eu3+, and Tb3+→Eu3+. However, under the excitation at 230 nm, the Tb3+→Eu3+ energy transfer contributes to the orange-red emission of Eu3+ and the green emission of Tb3+, in the absence of Bi3+ emission. The maximum energy transfer efficiency of Bi3+→ “Eu3+ and Tb3+” and Tb3+→ Eu3+ is 63% and 50% for (Y0.883Tb0.02Eu0.09Bi0.007)BO3. The (Y0.963Tb0.02Eu0.01Bi0.007)BO3 spheres exhibit a distinct excitation-dependent luminescence behavior. Facile switching the excitation wavelength from 260 nm to 230 nm yields emission color changing from orange to green yellow, which possesses the advanced security feature.

With the rapid development of the social economy, our lives are flooded with all kinds of counterfeit products. The public’s attitude of greedy for petty and cheap has encouraged unscrupulous manufacturers to take advantage of the opportunity to provide low-cost counterfeit products, suppress the profits of legitimate manufacturers, and also make the public lose confidence in the quality of the products. At present, the most widely used anti-counterfeiting system based on QR codes on the market. However, existing traceability systems are still mostly built in a centralized manner, and the central agency provides trust guarantees, but the public still has great doubts about the credibility of the central agency. The introduction of blockchain technology can perfectly solve the lack of existing architecture and the environment. In this research, we propose an IoT-based traceable drug anti-counterfeiting management system, a comprehensive plan from drug research and development, certification, production to sales. The framework we propose meets the requirements of information security for data integrity, resistance to replay attacks, irreversible information, and non-repudiation.

Counterfeit medications are known as the medications that were manufactured for the purpose of deceptively representing as authentic, effective and original in the market. Such medications cause severe health issues for patients. Counterfeited drugs have an inimical effect on the human health. The legal manufacturing companies also face threats to their revenue loss due to these counterfeited medicines. In this paper, we introduce a novel authentication protocol for anti-counterfeited drugs systems based on Internet of Things (IoT) to help checking the validity of drugs “unit dosage”. Our protocol uses the near-field communication (NFC) as it is convenient for mobile environment. The protocol also offers reliable update phase for NFC. Furthermore, our scheme is complemented with performance evaluation along with the use of random oracle model for formal security analysis. We also evaluate our protocol broadly using Py-Charm tool. Results show that proposed protocol resists most of common related flaws almost in equal computing cost with more added security features.

Product counterfeiting and theft are on-going problems in supply chains and retail environments, but not a lot of work has been done to address these problems through the cost-effective use of auto-identification technologies such as bar-codes, near-field communication (NFC), or radio-frequency identification (RFID). In this paper, we propose an RFID-based anti-counterfeiting and anti-theft scheme that can be used to detect counterfeit items at the point of purchase by a consumer. The proposed system is lightweight and suited for deployment in large-scale retail environments using low-cost passive tags. We also undertake an analysis of a recent scheme proposed by Tran and Hong to highlight some of the weaknesses of their scheme. A detailed security analysis of the proposed scheme shows that it satisfies the formal requirements of security correctness and is resistant to compromise through security attacks.

Falsified medicines are a major issue and a threat around the world. Various approaches are currently being investigated to mitigate the threat. In this study, a concept is tested that encodes binary digits (bits) on the surface of Fused Deposition Modelling (FDM) 3D printed geometries. All that is needed is a computer, a FDM 3D printer and a paper scanner for detection. For the experiments, eleven different formulations were tested, covering the most used polymers for 3D printing in pharma: Ethylene-vinyl acetate (EVA), polyvinyl alcohol (PVA), polylactic acid (PLA), Hypromellose (HPMC), ethyl cellulose (EC), basic butylated-methacrylate-copolymer (EPO), and ammonio-methacrylate-copolymer type A (ERL). In addition, the scanning process and printing process were evaluated. It was possible to print up to 32 bits per side on oblong shaped tablets corresponding to the dimensions of market preparations of oblong tablets and capsules. Not all polymers or polymer blends were suitable for this method. Only PVA, PLA, EC, EC+HPMC, and EPO allowed the detection of bits with the scanner. EVA and ERL had too much surface roughness, too low viscosity, and cooled down too slowly preventing the detection of bits. It was observed that the addition of a colorant or active pharmaceutical ingredient (API) could facilitate the detection process. Thus, the process could be transferred for 3D printed pharmaceuticals, but further improvement is necessary to increase robustness and allow use for more materials.

Luminescent lanthanide metal-organic frameworks (Ln-MOFs) have been shown to exhibit relevant optical properties of interest for practical applications, though their implementation still remains a challenge. To be suitable for practical applications, Ln-MOFs must be not only water stable but also printable, easy to prepare, and produced in high yields. Herein, we design and synthesize a series of m CB-Eu y Tb 1-y (y = 0-1) MOFs using a highly hydrophobic ligand mCBL1: 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane. The new materials are stable in water and at high temperature. Tunable emission from green to red, energy transfer (ET) from Tb3+ to Eu3+, and time-dependent emission of the series of mixed-metal m CB-Eu y Tb 1-y MOFs are reported. An outstanding increase in the quantum yield (QY) of 239% of mCB-Eu (20.5%) in the mixed mCB-Eu0.1Tb0.9 (69.2%) is achieved, along with an increased and tunable lifetime luminescence (from about 0.5 to 10 000 μs), all of these promoted by a highly effective ET process. The observed time-dependent emission (and color), in addition to the high QY, provides a simple method for designing high-security anticounterfeiting materials. We report a convenient method to prepare mixed-metal Eu/Tb coordination polymers (CPs) that are printable from water inks for potential applications, among which anticounterfeiting and bar-coding have been selected as a proof-of-concept., This work was financially supported by the MINECO (PID2019-106832RB-I00), MICINN through the Severo Ochoa Program for Centers of Excellence for the FUNFUTURE (CEX2019-000917-S, MDM-2017-0767, and SEV-2017-0706 projects), grant RTI2018-098027-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by ERDF A way of making Europe and the Generalitat de Catalunya (2017/SGR/1720 and SGR2017-1289). Z.L. is enrolled in the UAB Ph.D. program and acknowledges the China Scholarship Council (CSC) for his Ph.D. grant (201808310071)., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Structural colors can be induced on metals not only to fabricate logos or decorative motives but also to embed anti-counterfeit features for product protection. In this study, stainless steel (EN 1.4301) plates are colorized by growing a thin oxide layer using direct laser writing (DLW) and hidden anti-counterfeit measures are included on their surfaces by direct laser interference patterning (DLIP) processing. The periodic microstructures resulting from the DLIP treatment have a spatial period of 1 µm and act as relief diffraction gratings, featuring a characteristic diffraction pattern. These microstructures are not visible to the human eye but are easily detectable upon shining a coherent beam on the surface. Furthermore, the reflectance over the visible spectrum of the colorized surfaces with and without the DLIP microtexture is measured, giving low differences in the color perception following the so-called “CIE L*a*b*” color space. Finally, a demonstrator is fabricated, in which colorized fields with and without the security features are shown.

Leuchtstoffe anhaltender Lumineszenz im sichtbaren Spektrum eröffnen neue Möglichkeiten für Smartphone-basierte Anwendungen. Videoaufnahmen mit dem Smartphone mit 30 Bildern pro Sekunde können persistente Lumineszenzlebenszeiten einer Größenordnung von 100 ms und länger bestimmen. Die mit dem Smartphone aufgezeichneten Daten können benutzt werden um Anwendungen zu realisieren, die ansonsten nur für kurze Lebenszeiten möglich sind. Diese Alternative umgeht den Bedarf an teuren und relativ komplizierten Messinstrumenten, die für die Detektion von kurzen Lebenszeiten eingesetzt werden, wie zum Beispiel Multichannel scaling, Hochgeschwindigkeitskameras und Mikroskope zur Messung der Fluoreszenzlebenszeit. Diese Arbeit konzentriert sich auf die Detektion anhaltender Lumineszenz für Temperaturmessung und Anwendungen zur Fälschungssicherung mit dem Smartphone. Für die Smartphone-basierte Temperaturmessung wurde ein optimierter Gd2O2S: Eu3+ als Leuchtstoff verwendet, der mithilfe einer UV-Quelle angeregt werden kann. Der Leuchtstoff zeigte eine temperaturabhängige Lumineszenz, die hell und lange anhaltend genug war, um mit einer Smartphone-Kamera mit 30 Bildern pro Sekunde aufgezeichnet zu werden. Der Leuchtstoff hat eine Photolumineszenz-Quantenausbeute von 65 % und seine Lebenszeit nimmt mit steigender Temperatur ab. Dies wurde beobachtet über einen Temperaturbereich von 270 K bis 338 K, in dem die Lebenszeit von 1107 ms bis auf 100 ms abfiel. Die Analyse der zeitintegrierten Emission mit dem Smartphone nach einer Anregung mit 375 nm zeigte, dass die Temperaturen im Bereich von 270 K bis 338 K präzise gemessen werden konnten mit einer Messungenauigkeit unter 2 K. Darüber hinaus wurde die Lebenszeitmessung nicht durch Hintergrundstrahlung beeinträchtigt und ermöglichte somit eine genaue Temperaturmessung auch bei einer Hintergrundbeleuchtungsstärke von bis zu 1500 lx. Um eine Smartphone-basierte Fälschungssicherung zu realisieren wurden anhaltende Leuchtstoffe mit einstellbarer Lebenszeit bei Raumtemperatur benutzt, um dynamische, lumineszierende Etiketten zu entwickeln. Dynamische Fälschungssicherung wurde mithilfe von Ti4+-dotierten Gd2O2S: Eu3+ realisiert, wobei die Ti4+-Dotierung eine Kontrolle der Lebenszeit bei Raumtemperatur ermöglicht. Durch eine Veränderung der Kodotierung von 0 bis 0.09 mol% konnte die Lebenszeit von 1.17 ± 0.02 bis 5.95 ± 0.07 s durchgestimmt werden mit einer Anregung bei 375 nm. Durch eine Kombination von Leuchtstoffen mit verschiedenen Lebenszeiten konnten somit dynamische Etiketten zur Fälschungssicherung entwickelt werden. Die Lebenszeit der Leuchtstoffe für diese dynamischen Muster bestimmte dabei die Komplexität der Fälschungssicherung. Solche Muster, die aus einer Kombination von Leuchtstoffen mit großen Unterschieden in der Lumineszenzlebenszeit entwickelt wurden, konnten mit bloßem Auge beobachtet werden. Im Gegensatz dazu sind zeitliche Änderungen in Etiketten mit viel kürzerer Lebenszeit im Bereich von 0.2 s nur schwer mit bloßem Auge nachzuvollziehen. Mithilfe der Smartphone-Kamera mit einer Aufzeichnungsrate von 30 Bildern pro Sekunde können die versteckten Merkmale jedoch leicht entschlüsselt werden. In Hinblick auf die tatsächliche Anwendung am Verkaufsort, ist eine UV-Quelle einerseits normalerweise nicht vorhanden in einem Smartphone und andererseits stellt der Einsatz von UV-Strahlung für die Anregung der Leuchtstoffe eine Gesundheitsrisiko dar. Um die Nutzung einer UV-Quelle gänzlich zu vermeiden, wurden zweifarbige dynamische Etiketten zur Fälschungssicherung entwickelt. Diese erlauben eine Anregung mithilfe eines herkömmlichen Smartphone-Blitzlichtes während die Emission einfach mit der Kamera aufgezeichnet werden kann. Zu diesem Zweck wurden grün emittierende (SrAl2O4: Eu2+, Dy3+ (SAED)) und rot emittierende (CaS: Eu2+ und SrS: Eu2+) Leuchtstoffe entwickelt. Die Lebenszeit von SAED konnte variiert werden von 0.5 s bis 11.7 s durch Glühen des kommerziell erhältlichen Stoffes, was eine Verringerung der Störstellendichte im Material zur Folge hat. Die Lumineszenzlebenszeit von CaS: Eu2+ und SrS: Eu2+ konnte dagegen zwischen 0.1 bis 0.6 s und 150 bis 377 ms eingestellt werden mithilfe der Eu2+-Dotierdichte. Die Nutzung eines Smartphones ermöglicht nicht nur lebenszeit-basierte Temperaturmessungen ohne teure Messinstrumente, sondern eröffnet darüber hinaus eine kostengünstige Methode zur Authentifizierung von lumineszenzbasierten, dynamischen Markierungen zur Fälschungssicherung.

A method was developed to obtain YPO4:Eu dispersions of PVA as a luminescent inks. YPO4:Eu nanoparticles were prepared by precipitation followed by hydrothermal treatment. The dispersion preparation included systematic studies to prepare a stable colloidal system and to investigate the role of parameters affecting its stability and UV-excited YPO4:Eu emission intensity. The effect of PVA concentration was studied in detail for two different PVAs to determine the optimal parameters for its use as ink with specific luminescent properties. The type of interactions responsible for the dispersion stability was also investigated.

Microscale laser emissions have emerged as a promising approach for information encoding and anti-counterfeiting for their feature-rich spectra and high sensitivity to the surrounding environment. Compared with artificial materials, natural responsive biomaterials enable a higher level of complexity and versatile ways for tailoring optical responses. However, precise control of lasing wavelengths and spatial locations with biomolecules remains a huge challenge. Here, a biologically programmable laser, in which the lasing can be manipulated by biomolecular activities at the nanoscale, is developed. Tunable lasing wavelengths are achieved by exploiting the swelling properties of enzyme-responsive hydrogel droplets in a Fabry-Pérot microcavity. Both experimental and theoretical means demonstrate that inner 3D network structures and external curvature of the hydrogel droplets lead to different lasing thresholds and resonance wavelengths. Finally, inkjet-printed multiwavelength laser encoding and anti-counterfeiting are showcased under different scalabilities and environments. Hyperspectral laser images are utilized as an advanced feature for a higher level of security. The biologically encoded laser will provide a new insight into the development of biosynthetic and bioprogrammable laser devices, offering new opportunities for secure communication and smart sensing. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) This research was supported by A*STAR under its AME IRG Grant (Project No. A20E5c0085). This research was also supported by Ministry of Education, Singapore, under grant AcRF TIER 1-2021-T1-001-040 RG46/21.

Робота виконана на 93 сторінках, містить 40 ілюстрацій, 22 таблиці. При підготовці використовувалась література з 25 джерел. Актуальність теми Соціальні медіа змінили спосіб взаємодії людей та продовження повсякденного життя. Поширена практика обміну зображеннями в Інтернеті за допомогою таких соціальних мереж, як Instagram. Люди щодня завантажують і діляться мільярдами фотографій у соціальних мережах. Instagram дозволяє користувачам робити фотографії, застосовувати цифрові фотографічні фільтри та завантажувати фотографії на веб-сайт для соціальних мереж разом з короткими підписами. Величезна кількість людей стали жертвами підробки фотографій у цей технологічний вік. Деякі злочинці використовують програмне забезпечення для використання зображень як доказів, щоб заплутати суди. Щоб покінчити з цим, усі фотографії, мають бути позначені як правдиві чи підроблені. Соціальні медіа - це чудова платформа для обміну знаннями та їх поширення, але якщо немає обережності, люди можуть бути введені в оману і навіть спонукані до дій даними, що не відповідають дійсності. Дуже мало робіт було завершено навколо виявлення аудіо, зображень та відео підробок. Тим не менш, кілька досліджень тривають, щоб визначити, що можна зробити з неймовірним розповсюдженням підроблених фотографій. Згідно з дослідженнями, ідентифікувати фейкові новини та зображення дуже важко, оскільки пошук фактів новин на чистій основі залишається відкритою проблемою, і для вирішення проблеми можна використовувати лише декілька існуючих моделей. У словах та зображеннях, які використовуються у фейкових новинах, є деякі приховані характеристики, які можна ідентифікувати за допомогою набору прихованих властивостей. Мета та задачі дослідження Метою даної роботи є створення можливостей Розпізнавання підроблених зображень методами машинного навчання Рішення поставлених завдань та досягнуті результати В ході виконання роботи були досліджені такі поняття як машинне навчання, його види та методи. Було спроектовано та реалізовано застосунок для перевірки зображень на наявність в них підробок різними методами. У застосунку було навчено три моделі, які можна використовувати для, власне, перевірки даних. Реалізацію було перевірено на відповідність вимогам, зроблено висновки щодо обраних підходів, переваг подальшого розвитку. Виявлені шляхи покращення застосунку у майбутньому та способи його використання. Об’єкт досліджень Механізм розпізнавання підроблених зображень методами машинного навчання Предмет досліджень Процес розпізнавання підроблених зображень методами машинного навчання Наукова новизна Машинне навчання (Machine Learning) - це відносно молодий напрямок розвитку технологій у тому вигляді, в якому є зараз. Наукова новизна роботи полягає у дослідженні можливостей використання засобів машинного навчання для пошуку підроблених зображень, а також у збільшенні точності результатів, що отримуються на прикладі використання декількох обраних методів та моделей Практичне значення одержаних результатів Отримані результати можуть використовуватись для подальшого розвитку застосунку, з метою спрощення користування даними можливостями користувачами. Спектр де людям знадобиться даний застосунок дуже широкий, починаючи з журналістики, правоохороних органів, закінчуючи багатьма варіантами в приватних цілях. Work carried out on 93 pages containing 40 figures, 22 tables. The paper was written with references to 25 different sources. Topicality. Social media has changed the way people interact and continue their daily lives. It is common practice to share images on the Internet through social networks such as Instagram. People upload and share billions of photos on social networks every day. Instagram allows users to take photos, apply digital photo filters, and upload photos to a social networking website with short captions. A huge number of people have fallen victim to photo forgery in this technological age. Some criminals use software to use images as evidence to confuse courts. To end this, all photos must be marked as true or fake. Social media is a great platform for sharing and disseminating knowledge, but if you are not careful, people can be misled and even motivated to act with inaccurate data. Very little work has been completed on detecting audio, images and video forgeries. However, several studies are underway to determine what can be done with the incredible proliferation of fake photos. According to research, it is very difficult to identify fake news and images, because finding the facts of the news on a pure basis remains an open problem, and only a few existing models can be used to solve the problem. The words and images used in fake news have some hidden characteristics that can be identified by a set of hidden properties. Purpose. The purpose of this work is to create opportunities for the recognition of forged images by machine learning methods. Solution. In the course of the work such concepts as machine learning, types and methods were studied. An application was designed and implemented to check images for counterfeits using various methods. The application taught three models that can be used to validate data. Implementation was checked for compliance with the requirements, conclusions were made on the chosen approaches, the benefits of further development. Ways to improve the application in the future and ways to use it are identified. The object of research. The mechanism of recognition of forged images by machine learning methods. The subject of research. The process of recognizing fake images by machine learning methods. Scientific novelty. Machine Learning is a relatively young field of technology development as it is today. The scientific novelty of the work is to study the possibilities of using machine learning tools to search for fake images, as well as to increase the accuracy of the results obtained by using several selected methods and models. The practical value of research. The obtained results can be used for further development of the application, in order to simplify the use of these features for users. The range where people will need this application is very wide, from journalism, law enforcement, to many options for private purposes.

A precursor was prepared using a co-precipitation method to synthesize crystalline calcium tungstate. The prepared precursor was dried in an oven at 80 °C for 18 h. The dried powders, prepared without a heat treatment process, were observed in XRD analysis to be a crystalline CaWO4 phase, confirming that the synthesis of crystalline CaWO4 is possible even at low temperature. To use this crystalline CaWO4 as a light emitting material, rare earth ions were added when preparing the precursor. The CaWO4 powders doped with terbium (Tb3+) and europium (Eu3+) ions, respectively, were also observed to be crystalline in XRD analysis. The luminescence of the undoped CaWO4 sample exhibited a wide range of 300~600 nm and blue emission with a central peak of 420 nm. The Tb3+-doped sample showed green light emission at 488, 545, 585, and 620 nm, and the Eu3+-doped sample showed red light emission at 592, 614, 651, and 699 nm. Blue, green, and red CaWO4 powders with various luminescence properties were mixed with glass powder and heat-treated at 600 °C to fabricate a blue luminescent PiG disk. In addition, a flexible green and red light-emitting composite was prepared by mixing it with a silicone-based polymer. An anti-counterfeiting application was prepared by using the phosphor in an ink, which could not be identified with the naked eye but can be identified under UV light.

Cholesteric Spherical Reflectors (CSRs) are made of droplets of cholesteric liquid crystals (the same material under the screen of our mobile phones) but molded in a spherical shape and hardened into a solid. CSRs have a peculiar behavior when illuminated: they reflect light and produce unique optical patterns whose full display is hardly predictable. They have been argued to behave like an optical Physical Unclonable Function (PUF), therefore finding application in anti-counterfeiting, in particular for object authentication. However, a fundamental challenge remains open: to understand what makes each optical response unique and how to extract this identifying information reliably and repeatedly. We study the problem, and we design and discuss two pivotal procedures to build authentication protocols for objects coated with CSRs. We test the quality of our procedures against large data sets of pattern images: images from CSRs are used to calculate inter- and intra-distance; simulated patterns created artificially are used to measure security in terms of false positive ratio. Our procedures successfully cluster images coming from the same CSR, distinguishing them from images of different CSRs and decoys. Our work is one of the few that has studied procedures of information extraction for materials derived from CSRs. It advances the state of the art in this area, closing the gap between the research on optical PUFs and practical applications.

Invisible photonic crystal prints (IPCPs) are appealing for anti‐counterfeiting and information protection due to their capability in hiding and showing the encrypted information under specific conditions. Herein, the dual‐modal IPCPs based on responsive photonic crystals (PCs) with tunable photoluminescent (PL) and structural colors are reported. The responsive PCs are prepared by the self‐assembly of dyes doped silica particles into non/swellable polymers. The independent design and control over the optical response of the PL of the particles and structural colors of PCs enable the successful encryption of dual‐modal patterns. Under normal conditions, the as‐fabricated IPCP shows a fake pattern with uniform structural colors and thus hides the encrypted pattern due to the similar particles size, lattice constant, and refractive index of each region. In striking contrast, PL and structural colors‐based new patterns can be instantly and reversibly revealed when the IPCP is exposed to UV illumination or soaked in water. This work provides a new concept in designing and fabricating dual‐modal IPCPs, and facilitates their applications in the fields of color display, antifake package, and multilevel anti‐counterfeiting.

Counterfeiting of consumer goods is a critical problem which causes various negative impacts for consumers, enterprises and the whole economic ecosystem. Anti-counterfeit labels and packaging is one of the main solutions to help enterprises protect their brand against this concern. In this paper, we introduced a novel watermarking technique, which embeds a particular random micro-texture into a matrix barcode and transforms this one into a security layer for making packaging anti-counterfeited. The secured matrix barcode is hard to be reproduced by counterfeiters. In fact, any degradations caused by the counterfeiting process will change the statistical behaviors of the embedded micro-texture. Statistical detectors based on the hypothesis testing framework are also introduced to classify authentic and counterfeited printed barcodes. Experimental results confirm the usability and the effectiveness of the proposed anti-counterfeiting solution.

As the popularity of Internet of Things (IoT) increases, there is a considerable demand for the improvement of physical security, owing to the increase in edge devices. However, fabrication and measurement techniques used by attackers are also improving continuously, and hence, it is becoming increasingly difficult to ensure the security of each device using conventional approaches. To counter variable attacks in this context, the concept of nano-photonic metrics has been proposed, which is based on a functional collaboration between existing physical security and near-field optical techniques. In this approach, the optical signals obtained from optical near-field interactions, which are induced between the target with nano-scale structures and the tip of the scanning probe as the reader, are defined as the unique features of each device to be authenticated. When attackers attempt spoofing, they must fabricate not only clones of original nano-scale structures but also the scanning probe; otherwise, they cannot impersonate regular users. Moreover, the estimation of the nano-scale structures of the target and the characteristics of the probe is typically a complex, inverse problem. Therefore, a novel authentication is expected to be performed. In this paper, we report the results of the quantitative evaluations of the performance from the viewpoint of physical security and the experimental verification of the practicality of the proposed approach.

The synthesis of room temperature phosphorescent carbon dots (RTP-CDs) without any matrix is important in various applications. In particular, RTP-CDs with dual modes of excitation are more interesting. Here, we successfully synthesized matrix-free carbonized polymer dots (CPDs) that can generate green RTP under visible and ultraviolet light dual-mode excitation. Using acrylic acid (AA) and ammonium oxalate as precursors, a simple one-pot hydrothermal method was selected to prepare AA-CPDs. Here, acrylic acid is easy to polymerize under high temperature and high pressure, which makes AA-CPDs form a dense cross-linked internal structure. Ammonium oxalate as a nitrogen source can form amino groups during the reaction, which reacts with a large number of pendant carboxyl groups on the polymer chains to further form a cross-linked structure. The carboxyl and amino groups on the surface of AA-CPDs are connected by intermolecular hydrogen bonds. These hydrogen bonds can provide space protection (isolation of oxygen) around the AA-CPDs phosphor, which can stably excite the triplet state. This self-matrix structure effectively inhibits the non-radiative transition by blocking the intramolecular motion of CPDs. Under the excitation of WLED and 365 nm ultraviolet light, AA-CPDs exhibit the phosphorescence emission at 464 nm and 476 nm, respectively. The naked-eye observation exceeds 5 s and 10 s, respectively, and the average lifetime at 365 nm excitation wavelength is as long as 412.03 ms. In addition, it successfully proved the potential application of AA-CPDs in image anti-counterfeiting.

There is a strong request expressed by industrial manufacturers and governmental agencies for the development of technologies allowing both authentication of sensitive products and storage of traceability data on them. In this context, this thesis’ purpose is to elaborate a new generation of photoluminescent nano-object-based “graphic” markers (e.g. QR code). Nanometric InP@ZnS and PbS colloidal quantum dots were synthesized to exhibit two non-coupled photoluminescence emissions in the visible and in the short-wave infrared ranges. In order to elaborate markers from these quantum dots, two complementary processes were developed: (i) directed assembly of quantum dots by nanoxerography combined with electrical microcontact printing and (ii) micropatterning of a quantum dot-embedded nanocomposite by UV curing nanoimprint lithography. The first process involves injecting electrostatic charges into an electret material to form the wanted marker’s patterns which then serve as electrostatic traps to assemble the quantum dots. The resulting marker is then integrated to the product via a transfer step. The second process involves embedding the quantum dots into a light-activated adhesive epoxy matrix then micropatterning the nanocomposite directly onto the product with the wanted marker’s patterns. Precise tuning of each process’ step parameters allowed to finely monitor the markers’ lateral size (from centimeter down to a few micrometers) and photoluminescence properties. Studies revealed that UV curing nanoimprint lithography allows a much larger range of photoluminescence intensity than nanoxerography, while the latter allows smaller marker lateral sizes. Conducted developments have finally been used to integrate markers on diverse sensitive products related to national security: official documents, textiles, electronic components and ammunition for firearms.; Une forte demande des fabricants industriels et des agences gouvernementales concerne le développement de technologies permettant d’authentifier les produits sensibles tout en y inscrivant des informations de traçabilité. Dans ce contexte, l’objectif de cette thèse est d’élaborer une nouvelle génération de marqueurs « graphiques » de type QR code à base de nano-objets photoluminescents. Des quantum dots colloïdaux d’InP@ZnS et de PbS de quelques nanomètres de diamètre ont été synthétisés pour générer deux émissions de photoluminescence non couplées dans les domaines du visible et de l’infrarouge proche. Afin d’élaborer les marqueurs à partir de ces quantum dots, deux procédés complémentaires ont été développés : (i) l’assemblage dirigé des quantums dots par nanoxérographie via la technique de microcontact printing électrique et (ii) la microstructuration d’un nanocomposite à base des quantum dots par nanoimpression assistée par UV. Le premier procédé consiste à injecter des charges électrostatiques dans un matériau électret sous la forme du marqueur souhaitée, puis à piéger électrostatiquement les quantum dots sur ces motifs de charges. Le marqueur formé est alors intégré au produit via une étape de transfert. Le deuxième procédé consiste à incorporer les quantum dots dans une matrice de colle époxy photosensible, puis à microstructurer le nanocomposite à même le produit sous la forme du marqueur souhaitée. L’ajustement précis des paramètres de chacune des étapes de ces deux procédés a permis de finement contrôler la taille latérale (de quelques micromètres à un centimètre) et les propriétés de photoluminescence des marqueurs. L’étude réalisée a révélé que la nanoimpression assistée par UV permet d’accéder à une plage d’intensité de photoluminescence nettement plus importante que la nanoxérographie, mais que cette dernière offre des tailles latérales de marqueurs plus réduites. Les développements menés ont finalement été mis à profit pour intégrer des marqueurs sur des produits sensibles variés et liés en particulier au domaine de la Défense, tels que des documents officiels, matériaux textiles, composants électroniques ou encore munitions pour armes à feu.

Rare-earth doped nanoparticles (RENPs) have been widely used for anti-counterfeiting and security applications due to their light frequency conversion features: they are excited at one wavelength, and they display spectrally narrow and distinguished luminescence peaks either at shorter wavelengths (i.e., frequency/energy upconversion) or at longer wavelengths (frequency/energy downconversion). RENPs with a downconversion (DC) photoluminescence (PL) in short-wave infrared (SWIR) spectral range (~1,000–1,700 nm) have recently been introduced to anti-counterfeiting applications, allowing for multilevel protection based on PL imaging through opaque layers, due to a lesser scattering of SWIR PL emission. However, as the number and spectral positions of the discrete PL bands exhibited by rare-earth ions are well-known, it is feasible to replicate luminescence spectra from RENPs, which results in a limited anti-counterfeiting security. Alternatively, lifetime of PL from RENPs can be used for encoding, as it can be finely tuned in broad temporal range (i.e., from microseconds to milliseconds) by varying type of dopants and their content in RENPs, along with the nanoparticle morphology and size. Nevertheless, the current approach to decoding and imaging the RENP luminescence lifetimes requires multiple steps and is highly time-consuming, precluding practical applications of PL lifetime encoding for anti-counterfeiting. Herein, we report the use of a rapid lifetime determination (RLD) technique to overcome this issue and introduce real-time imaging of SWIR PL lifetime for anti-counterfeiting applications. NaYF4:20% Yb, x% Er (x = 0, 2, 20, 80)@NaYF4 core@shell RENPs were synthesized and characterized, revealing DC PL in SWIR region, with maximum at ~1,530 nm and PL lifetimes ranging from 3.2 to 6 ms. Imaging of the nanoparticles with different lifetimes was performed by the developed time-gated imaging system engaging RLD method and the precise manipulation of the delay between the excitation pulses and camera gating windows. Moreover, it is shown that imaging and decrypting can be performed at a high rate (3–4 fps) in a cyclic manner, thus allowing for real-time temporal decoding. We believe that the demonstrated RLD-based fast PL lifetime imaging approach can be employed in other applications of photoluminescent RENPs.

Cork stoppers were shown to have unique characteristics that allow their use for authentication purposes in an anti-counterfeiting effort. This authentication process relies on the comparison between a user’s cork image and all registered cork images in the database of genuine items. With the growth of the database, this one-to-many comparison method becomes lengthier and therefore usefulness decreases. To tackle this problem, the present work designs and compares hashing-assisted image matching methods that can be used in cork stopper authentication. The analyzed approaches are the discrete cosine transform, wavelet transform, Radon transform, and other methods such as difference hash and average hash. The most successful approach uses a 1024-bit hash length and difference hash method providing a 98% accuracy rate. By transforming the image matching into a hash matching problem, the approach presented becomes almost 40 times faster when compared to the literature.

Innovative solutions addressing product anti-counterfeiting and record provenance have been deployed across today's internationally spanning supply chain networks. These product anti-counterfeiting solutions are developed and implemented with centralized system architecture relying on centralized authorities or any form of intermediaries. Vulnerabilities of centralized product anti-counterfeiting solutions could possibly lead to system failure or susceptibility of malicious modifications performed on product records or various potential attacks to the system components by dishonest participant nodes traversing along the supply chain. Blockchain technology has progressed from merely with a use case of immutable ledger for cryptocurrency transactions to a programmable interactive environment of developing decentralized and reliable applications addressing different use cases globally. In this research, so as to facilitate trustworthy data provenance retrieval, verification and management, as well as strengthening capability of product anti-counterfeiting, key areas of decentralization and feasible mechanisms of developing decentralized and distributed product anti-counterfeiting and traceability ecosystems utilizing blockchain technology, are identified via a series of security and threat analyses performed mainly against NFC-Enabled Anti-Counterfeiting System (NAS) which is one of the solutions currently implemented in the industry with centralized architecture. A set of fundamental system requirements are set out for developing a blockchain-enabled autonomous and decentralized solution for supply chain anti-counterfeiting and traceability, as a secure and immutable scientific data provenance tracking and management platform in which provenance records, providing compelling properties on data integrity of luxurious goods, are recorded and verified automatically, for supply chain industry., 20 pages

Hexagonal boron nitride was synthesized by pyrolysis using boric acid and melamine. At this time, to impart luminescence, rare earth cerium ions were added to synthesize hexagonal boron nitride nanophosphor particles exhibiting deep blue emission. To investigate the changes in crystallinity and luminescence according to the re-heating temperature, samples which had been subjected to pyrolysis at 900 °C were subjected to re-heating from 1100 °C to 1400 °C. Crystallinity and luminescence were enhanced according to changes in the reheating temperature. The synthesized cerium ion-doped hexagonal boron nitride nanoparticle phosphor was applied to the anti-counterfeiting field to prepare an ink that can only be identified under UV light.

Sustainability in electronics has a growing importance due to, e.g. increasing electronic waste, and global and European sustainability goals. Printing technologies and use of paper as a substrate enable manufacturing of sustainable electronic devices for emerging applications, such as the multi-layer anti-counterfeit label presented in this paper. This device consisted of electrochromic display (ECD) element, NFC (near field communication) tag and circuitry, all fully roll-to-roll (R2R) printed and assembled on plastic-free paper substrate, thus leading to a sustainable and recyclable device. Our setup uses harvested energy from HF field of a smartphone or reader, to switch an electrochromic display after rectification to prove authenticity of a product. Our novelty is in upscaling the manufacturing process to be fully printable and R2R processable in high-throughput conditions simulating industrial environment, i.e. in pilot scale. The printing workflow consisted of 11 R2R printed layers, all done in sufficient quality and registration. The printed antennas showed sheet resistance values of 32.9±1.9 mΩ/sq. The final yield was almost 1500 fully printed devices, and in R2R assembly over 1400 labels were integrated with 96.5% yield. All the assembled tags were readable with mobile phone NFC reader. The optical contrast (ΔE*) measured for the ECDs was over 15 for all the printed displays, a progressive switching time with a colour change visible in less than 5 s. The smart tag is ITO-free, plastic-free, fully printed in R2R and has a good stability over 50 cycles and reversible colour change from light to dark blue.

Ultralong room temperature phosphorescence is employed in information encryption, chemical sensing, lighting, and imaging on account of its long lifetime and high signal-to-noise ratio. As the triplet excitons can be easily quenched and interfered by nonradiative transition process, it is difficult to obtain long-lived phosphorescence through conventional methods. Herein, a general design strategy to form cross-linked networks by click chemistry is presented for efficiently promoting the phosphorescence performance. Using the hydrogen bonding interactions formed between C-O···H-N units and covalently cross-linked network by the B-O bond, the rigidity of the entire system is greatly enhanced, so the radiative transition process is well strengthened. Interestingly, under the influence of water molecule, the afterglow colors of the system change from blue (488 nm) to green (510 nm). Because of the presence of cross-linked network, the emission is not directly quenched when the system is intervened by water. Having long phosphorescence lifetime (841.06 ms) and high quantum yield (10.48%), the obtained system is utilized for anti-counterfeiting demonstration. This strategy paves a new way for the design of amorphous ultralong room temperature phosphorescence materials by efficient and user-friendly click chemistry. Ministry of Education (MOE) This work was financially supported by the National Natural Science Foundation of China (Grant No. 21875025), the Special Program of Chongqing Science and Technology Commission (Grant No. cstc2018jcyjAX0296), the Innovation Research Group at Institutions of Higher Education in Chongqing (Grant No. CXQT19027), the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No. KJZD-K201801101), the Chongqing Talent Program, Science and Technology Project of Banan District, the Innovation Support Plan for the Returned Overseas of Chongqing (Grant No. cx2020052), and the Graduate Student Innovation Program of Chongqing University of Technology (Grant No. clgycx20203012). The research was also supported by the Ministry of Education Singapore under the Academic Research Funds (Grant Nos. RT12/19 and MOET2EP10120-0003).

International audience; Lanthanide-doped up-conversion (UC) materials with color tunable property show promising application in many fields, such as biological imaging, optical multiplexing, and information security. Although great efforts have been devoted to regulate UC emission color via modifying chemical composition, crystal structure, or external stimuli condition, it is remain a daunting challenge to develop a general strategy that probably suitable for various lanthanide-doped nano-systems. Herein, we verify the cross-relaxation possibility between sensitizer Yb3+ and activator Er3+ as well as Er3+- Er3+ pairs can be well modified by engineering the crystal lattice distortion of matrix, leading to the evident UC emission color variations. Specifically, with incorporating Al3+ or Ca2+ ions into the Yb/Er co-doped BaF2 nanocrystals (NCs) contained glass ceramics (GCs), the contraction of the crystal lattice lead to the change of UC emission color from green to red. On the contrary, the high laser excitation power results in the lattice expansion of the Al3+-doped BaF2:Yb/Er GCs at different Yb3+ concentration as well as Al3+ doped CaF2 GCs, which leads to the greatly increased green-to-red ratio. These multi-color UC GCs show potential application in anti-counterfeiting filed. Our results open up a general avenue for the control of UC emission color via engineering crystal lattice distortion.

Personalized drug delivery systems (PDDS), implying the patient-tailored dose, dosage form, frequency of administration and drug release kinetics, and digital health platforms for diagnosis and treatment monitoring, patient adherence, and traceability of drug products, are emerging scientific areas. Both fields are advancing at a fast pace. However, despite the strong complementary nature of these disciplines, there are only a few successful examples of merging these areas. Therefore, it is important and timely to combine PDDS with an increasing number of high-end digital health solutions to create an interactive feedback loop between the actual needs of each patient and the drug products. This review provides an overview of advanced design solutions for new products such as interactive personalized treatment that would interconnect the pharmaceutical and digital worlds. Furthermore, we discuss the recent advancements in the pharmaceutical supply chain (PSC) management and related limitations of the current mass production model. We summarize the current state of the art and envision future directions and potential development areas.

Room-temperature phosphorescent (RTP) carbon dots (CDs) have promising applications in bioimaging, anticounterfeiting, and information encryption owing to their long lifetimes and wide Stokes shifts. Numerous researchers are interested in developing highly bright RTP CDs using environmentally friendly and safe synthesis processes (e.g., natural raw materials and zero-pollution production pathways). In this study, we successfully synthesized RTP CDs using a hydrothermal process employing natural vitamins as a raw material, ethylenediamine as a passivator, and boric acid as a phosphorescent enhancer, which is referred to as phosphorescent CD (PCD). The PCDs exhibit both bright blue fluorescence emission and green RTP emission, with a phosphorescence lifetime as long as 293 ms and an excellent green afterglow visible to the naked eye for up to 7.0 s. The total quantum yield is 12.69%. The phosphorescence quantum yield (PQY) is up to 5.15%. Based on the RTP performance, PCDs have been successfully employed for anticounterfeiting and information protection applications. The results of this study provide a green strategy for the scalable synthesis of RTP materials, which is a practical method for the fabrication of RTP materials with high efficiency and long afterglow lifetimes.

The anti-counterfeiting is an ongoing problem whose solution requires significant human and financial resources. Eventual additional expenses are reflected in the final price of a protected product that means the customers pay for anti-counterfeiting. Simple and inexpensive method for document authenticity verification development and implementation, aimed to discourage documents counterfeiting in general and as a consequence guarantee authenticity of accompanying documents, bring the customer confidence in a product quality, reducing the product price. The article represents a novel method of paper document validation using modern smartphones. The proposed paper document validation method is based on paper surface structure comparison of the registered reference document and the candidate document under validation. The method allows regular owner of a smartphone to quickly validate the paper document without having any knowledge about the validation process itself. The proposed solution is characterized by high availability and scalability, which are dictated by wide popularity of smartphones and high demand for tools from this category. To achieve stable and effective work of such system the special technical design approach is required. The usage of microservice based approach for system design and implementation allows to solve mentioned problem and to allocate the hardware resources efficiently to make the system work under high load stable.

Owing to their superior fluorescence performance, inexpensive synthesis and nontoxic nature, carbon dots (C-dots) are systematically explored in a variety of applications; in this review, we outline and critically discuss recent trends with respect to their potential exploitation in criminal investigation, forensic toxicology and anti-counterfeit interventions. Capitalising on their colour-tuneable behaviour (in the sense that they adopt different colours with respect to the incident radiation), C-dot-based compositions are ideal for the visual enhancement of latent fingerprints, affording improved contrast against multicoloured and patterned backgrounds. As highly sensitive and highly selective optical nanoprobes, C-dots show excellent analytical performance in detecting biological compounds, drugs, explosives, heavy metals and poisonous reactants. In addition, benefiting from their versatile structural and chemical composition, C-dots can be incorporated into ink and polymeric formulations capable of functioning as a new generation of cost-effective barcodes and security nanotags for object authentication and anti-counterfeit applications. Translating these encouraging research outcomes into real-life innovations with significant social and economic impact requires an open, multidisciplinary approach and a close synergy between materials scientists, biologists, forensic investigators and digital engineers.

With the development of commodity economy, the emergence of fake and shoddy products has seriously harmed the interests of consumers and enterprises. To tackle this challenge, customized 2D barcode is proposed to satisfy the requirements of the enterprise anti-counterfeiting certification. Based on information hiding technology, the proposed approach can solve these challenging problems and provide a low-cost, difficult to forge, and easy to identify solution, while achieving the function of conventional 2D barcodes. By weighting between the perceptual quality and decoding robustness in sensing recognition, the customized 2D barcode can maintain a better aesthetic appearance for anti-counterfeiting and achieve fast encoding. A new picture-embedding scheme was designed to consider 2D barcode, within a unit image block as a basic encoding unit, where the 2D barcode finder patterns were embedded after encoding. Experimental results demonstrated that the proposed customized barcode could provide better encoding characteristics, while maintaining better decoding robustness than several state-of-the-art methods. Additionally, as a closed source 2D barcode that could be visually anti-counterfeit, the customized 2D barcode could effectively prevent counterfeiting that replicate physical labels. Benefitting from the high-security, high information capacity, and low-cost, the proposed customized 2D barcode with sensing recognition scheme provide a highly practical, valuable in terms of marketing, and anti-counterfeiting traceable solution for future smart IoT applications.

Barium tungstate (BaWO4) powders with various sintering temperatures, and BaWO4:Dy3+ phosphor samples with concentrations of different rare-earth (RE) activator ions (Dy3+, Sm3+, Tb3+) were prepared through co-precipitation. The structural, morphological, and photoluminescent characteristics of barium tungstate phosphors depend on the concentration of RE ions. The crystallographic characteristics of the synthesized BaWO4 were analyzed using X-ray diffraction (XRD) patterns. The size and shape of the crystalline particles were estimated based on images measured with a field emission scanning electron microscope (FE-SEM). As the sintering temperature of the BaWO4 particles increased from 400 °C to 1000 °C, the size of the particles gradually increased and showed a tendency to clump together. In the sample doped with 7 mol % Dy3+ ions, the intensity of all emission bands reached their maximum. The emission spectra of the RE3+-doped BaWO4 powders by excitation at 325 nm were composed of yellow (Dy3+), red (Sm3+), and green (Tb3+) band at 572, 640, and 544 nm. This indicates that most of the RE3+ ions absorbed the position without reversal symmetry in the BaWO4 lattice. These results propose that strong emission intensity and tunable color for the phosphors can be accomplished by rare-earth doped host with an suitable quantity. In addition, the phosphor thin films, having high transparency from aqueous colloidal solutions, were deposited on banknotes, and it is considered whether it is suitable for anti-counterfeiting applications.

Simple, low-cost, robust, and scalable fabrication of microscopic linear barcodes with high levels of complexity and multiple authentication layers is critical for emerging applications in information security and anti-counterfeiting. This manuscript presents a novel approach for fabrication of microscopic linear barcodes that can be visualized under Raman microscopy. Microfluidic channels are used as molds to generate linear patterns of end-grafted polymers on a substrate. These patterns serve as templates for area-selective binding of colloidal gold nanoparticles resulting in plasmonic arrays. The deposition of multiple taggant molecules on the plasmonic arrays via a second microfluidic mold results in a linear barcode with unique Raman fingerprints that are enhanced by the underlying plasmonic nanoparticles. The width of the bars is as small as 10 mu m, with a total barcode length on the order of 100 mu m. The simultaneous use of geometric and chemical security layers provides a high level of complexity challenging the counterfeiting of the barcodes. The additive, scalable, and inexpensive nature of the presented approach can be easily adapted to different colloidal nanomaterials and applications. (C) 2020 Elsevier Inc. All rights reserved.