Anti-counterfeiting Labels Research Articles

Robust and Versatile Biodegradable Unclonable Anti-Counterfeiting Labels with Multi-Mode Optical Encoding Using Protein-Mediated Luminescent Calcite Signatures.

Physical unclonable functions (PUFs) are emerging as a cutting-edge technology for enhancing information security by providing robust security authentication and non-reproducible cryptographic keys. Incorporating renewable and biocompatible materials into PUFs ensures safety for handling, compatibility with biological systems, and reduced environmental impact. However, existing PUF platforms struggle to balance high encoding capacity, diversified encryption signatures, and versatile functionalities with sustainability and biocompatibility. Here, all-biomaterial-based unclonable anti-counterfeiting labels featuring multi-mode encoding, multi-level cryptographic keys, and multiple authentication operations are developed by imprinting biomimetic-grown calcites on versatile silk protein films. In this label, the inherent non-clonability comes from the randomized characteristics of calcites, mediated by silk protein during crystal growth. The successful embedding of photoluminescent molecules into calcite lattices, assisted by silk protein, allows the resulting platform to utilize fluorescence patterns alongside birefringence for high-capacity encoding. This design facilitates easy and rapid authentication through Hamming distance and convolutional neural networks using standard cameras and portable microscopes. Moreover, angle-dependent polarization patterns enable multi-level key generation, while multi-spectral fluorescence signals offer multi-channel keys. The developed anti-counterfeiting labels combine biodegradability, green manufacture, easy authentication, high-level complexity, low cost, robustness, patternability, and versatility, offering a practical and high-security solution to combat counterfeiting across various applications.

Differentiated Intra-Ligand Charge Transfer Boosting Multicolor Responsive MOF Heterostructures as Robust Anti-Counterfeiting Labels.

Metal-organic framework (MOF) heterostructures with hybrid architectures and abundant functional sites possess great potential applications in advanced information security, yet still suffer from the harsh stimuli mechanisms with restrained emission control. Herein, the differentiated design strategy on intra-ligand charge transfer is first reported to realize smart-responsive multicolor MOF heterostructures as robust anticounterfeiting labels. Designed similar MOF blocks with the differentiated intra-ligand charge transfer are integrated via time-dependent epitaxial growth to form multicolor MOF heterostructures. Different numbers of electron-donating groups in MOF blocks offer distinct space regulation on the torsion of charge transfer ligands, which trigger the diverse responsive emissions under the same mild stimuli, thus generating multiple tunable color patterns in heterostructures. These spatial-resolved MOF heterostructures with stable multicolor responsive modes permit the encoding of fingerprint information, which further functions as robust anti-counterfeiting labels with high-security convert states. These results offer a promising route for the function-oriented exploitation of smart-responsive MOF heterosystems for advanced information anticounterfeiting.

Automated production of batched unclonable micro-patterns anti-counterfeiting labels with strong robustness and rapid recognition speed

Anti-counterfeiting technologies are indeed crucial for information security and protecting product authenticity. Traditional anti-counterfeiting methods have their limitations due to their clonable nature. Exploring new technologies, particularly those based on pixel-level textures, is a promising avenue to address the clonable issue due to high encoding capacity. However, research in this field is still in its early stages. This work introduces a new fluorescent anti-counterfeiting label technology with four key characteristics: efficient laser etching, high-throughput fabrication and segmentation, robustness aided by data augmentation, and an exceptionally high recognition speed. Specifically, the etching achieves a speed of 1,200 labels/3s, the high-throughput procedures yield a rate of 2,400 labels/4 min, and the total count is about 5.2 × 104 labels. The number of labels is further augmented to about 5.2 × 106 by implementing arbitrary rotation and brightness variation to enhance the robustness in the recognition procedure. We divide these labels into 44 categories based on differences in patterns. Utilizing machine learning methods, we have achieved a total recognition (including extraction and search process) time per label averaging 421.96 ms without classification, and 40.13 ms with classification. Specifically, the search process with classification is nearly fiftieth times shorter than the non-classification method, reaching 8.52 ms in average. The overall recognition time is much faster than previous works, and achieves an accuracy of over 98.7%. This work significantly increases the practical significance of pixel-level anti-counterfeiting labels.

Multilevel Stimuli-Responsive Smart "Sandwich" Label with Physical Unclonable Functions Bionic Wrinkles and Space-Selective Fluorescence Patterns.

With the increasing popularity of the internet, it brings convenience to lives while also increases security risks. Physical Unclonable Functions (PUFs) can generate random, unclonable, and unique identifiers using their inherent physical characteristics, which have broad prospects in anti-counterfeiting. Herein, inspired by the irregular tree bark fissures and random skin wrinkles found in nature, a method for creating complex micro-wrinkles with unclonable random patterns is proposed by simply stretching hydrogels. The random texture information contained in the micro-wrinkles is digitized into binary codes using an adaptive threshold algorithm. Additionally, a novel "sandwich" label with a multilevel intelligent anti-counterfeiting system is proposed. The first-level involves photoluminescence encryption with adjustable luminescence within visible light range and modulated luminescence at different excitation wavelengths; the second-level includes strain-related mechanical encryption, and the third-level consists of highly random and unclonable micro-wrinkles. The certification difficulty increases as the anti-counterfeiting grade increases, thereby enhancing label security. Furthermore, space-selective doping of rare earth metal-organic framework (RE-MOF) fluorescent materials in hydrogels is achieved through the use of screen-printing technology. The concept of novel multilevel smart anti-counterfeiting PUF labels will further enhance current levels of counterfeiting prevention.

Hydrogen-Bonded Organic Frameworks for Antibiotic Fluorescent Sensing Artificial Intelligence-Enhanced Anticounterfeiting.

The paramount importance of anticounterfeiting measures in safeguarding consumers from counterfeit products lies in their ability to ensure product safety and reliability. Advanced luminescent anticounterfeiting materials, particularly those responsive to multiple stimuli, afford a dynamic and multilayered security assurance. This study presents the synthesis of a novel material, Eu/Tb@GC-3, via postsynthetic modification, which exhibits notable photoluminescent properties with emission at 544 and 614 nm. The material demonstrates high selectivity and sensitivity in detecting Nitrofural and Enrofloxacin, with limits of detection at 0.0122 and 0.0280 μM, respectively. Furthermore, multistimulus responsive luminescent fibers and inks were developed, facilitating intelligent anticounterfeiting labels. The integration of these labels with back-propagation neural networks (BPNNs) significantly enhances pattern recognition and authentication capabilities, providing an efficacious strategy to combat counterfeit products and ensure consumer safety.

Polymer-stabilized cholesteric liquid crystals with multi-state reversibility for applications in advanced smart adjustable anti-counterfeiting and energy-saving displays

The creation of an anti-counterfeiting material with reflection color, fluorescence, infrared imaging, and electrical property information will increase the level of anti-counterfeiting. However, the creation of such a material has proved to be extremely challenging. In this study, twin anti-counterfeiting labels with intelligently tunable patterns were obtained through a strategy of PMMA loaded chiral molecules via diffusing on the micrometer scale. In order to enhance anti-counterfeiting ability, the multi-mode intelligently modulated advanced anti-counterfeiting material was obtained through the strategy of introducing photo-isomerizing dithienylethene and infrared-shielding Cs0.33WO3 nanoparticles. This material can be reversibly converted into fluorescent, reflected colors, infrared, and electrical characteristic signals. The encrypted information is displayed with red fluorescence under UV light irradiation. Furthermore, the encrypted information can be reversibly displayed and erased under repeated stimulation by voltage and pressure, heating and cooling, UV, visible and near infrared (NIR) light. The aim of our work is to create a simple method to prepare complex patterns of structural and fluorescent color anti-counterfeiting films with the improved anti-counterfeiting capability. Based on this, the strategy of co-doping fluorescent molecules and photochromic molecules in liquid crystals combined with etching technology has realized a multiple anti-counterfeiting mode with a higher level of security. The advanced multiple anti-counterfeiting mode can output encrypted information of multiple states which will greatly improve the level of anti-counterfeiting. In terms of display, we obtained billboards with complex patterns, price intelligently tunable and full-color display by diffusion S5011 in liquid crystals, thus extending their application in the field of electronic shelf labels.

Study on luminescence properties and anti-counterfeiting application of Sr3Y2Ge3O12 doped Mn2+ long afterglow materials

Traditional anti-counterfeiting materials have the characteristics of static display of anti-counterfeiting patterns and are easy to be disturbed by background patterns. Consequently, the development of novel luminous materials represents an imperative objective. As a novel class of matrix material, Sr3Y2Ge3O12 has demonstrated considerable potential for application in the field of anti-counterfeiting. In this study, strontium yttrium germanate doped manganese ion long afterglow material was prepared by the high temperature solid phase method, and its afterglow performance and dynamic anti-counterfeiting application were studied. The experimental results show that the sample exhibits excellent luminescence characteristics. It is observed that the sample excited at 260 nm shows an emission band centred at 634 nm and a high-energy turning point at 578 nm. Using screen printing technology, design a variety of anti-counterfeiting labels. The prepared samples after ultraviolet excitation can maintain the pattern for a long time, and with the passage of time, the pattern shows dynamic attenuation, which is important in enhancing the anti-counterfeiting effect and improving product safety.

IR Hidden Patterns for Security Labels.

Authentication of a product's originality by anticounterfeiting labels represents a crucial point toward protection against forgery. Fast and scalable fabrication methods of original labels with a high degree of protection are in high demand for the protection of valuable goods. Here, we propose a simple strategy for fabrication of hidden security tags with IR luminescent readout by the direct femtosecond laser patterning of silicon-erbium-silicon sandwiched thin films. The choice of laser processing parameters makes possible the creation of random or quasi-regular self-organized surface nanotextures. The controlled laser-driven oxidation accompanying this process provides simultaneous regulation of the film's optical properties and spontaneous emission yield of the embedded Er atoms. The regimes are detected when optically similar patterned areas demonstrate different Er emission intensities, allowing us to create hidden security tags with facile readout at the C-band telecommunication wavelengths. The obtained results take another step toward the application of IR-luminescent erbium-based anticounterfeiting labels for covert and/or forensic security levels.

Enhanced electro-optical properties of polymer dispersed liquid crystals doped with functional nanofibers for applications of efficient smart windows and advanced anti-counterfeiting

The development of polymer-dispersed liquid crystal (PDLC) capable of infrared smart tuning and displaying distinct information under ultraviolet, visible, and infrared light presents significant challenges. These challenges include the tuning of electro-optical properties and IR reflectivity, the preparation of complex patterns, and the display of different display states under various stimuli. In this work, nanofibers doped with alumina-zinc oxide nanoparticles (AZO NPs) and loaded with cesium tungstate nanoparticles (Cs0.33WO3 NPs) into PDLC not only enhanced their electro-optical properties but also added infrared shielding. Temperature regulation tests demonstrate that PDLC films can intelligently modulate infrared light reflection, offering superior shading and temperature regulation capabilities. PDLC smart windows integrated with nanofibers achieve a temperature coordination function, maintaining a temperature differential of 12.1 °C compared to standard PDLC. This significant enhancement underscores their potential for applications in thermally regulated smart windows. In addition, a full-wavelength anti-counterfeiting mode for PDLC was developed using a screen-printing strategy to display different information under various wavelengths of light. Noteworthily, the anti-counterfeiting system exhibits a bright fluorescent pattern under UV light, a scattering pattern under visible light, and an infrared-modulated pattern when viewed with an infrared detector. Furthermore, an advanced dynamic anti-counterfeiting mode with time response was created using nanofibers loaded with different concentrations of Cs0.33WO3 NPs. This advanced anti-counterfeiting material can be used as multimodal and dynamic anti-counterfeiting label, which greatly facilitates the development of novel anti-counterfeiting and optical sensing materials.

Anti-counterfeiting labels with controllable and anti-interference coding information based on core–shell Ag@SiO2 nanomaterials for ink printing

The core–shell structured Ag@SiO2 nanomaterial integrated with surface-enhanced Raman scattering (SERS) spectroscopy promises a critical application in anti-counterfeiting. Security labels have been fabricated based on Ag@SiO2 embedded with Raman reporters. The Ag@SiO2 nanomaterial shows good stability and excellent anti-interference property for anti-counterfeiting. Multiple kinds of Raman probe molecules have been anchored in the Ag@SiO2 labels to provide specific and abundant encoding information. The flexible encoding security information could be controlled conveniently by adjusting probe molecules, which not only enrich the SERS information but also improve the level of anti-counterfeiting. Furthermore, the Ag@SiO2 shown excellent stability in organic solvent, and successfully used in ink for the anti-counterfeiting application.

Photochromic Spiropyran-Based Dual-Emitting Luminescent Hybrid Films for Dynamic Information Anticounterfeiting.

Photoluminescent materials are widely used for information storage and anticounterfeiting, while most of them have the disadvantages of static information performance and weak processability, which is still a challenging task in developing dynamic anticounterfeiting materials with high security levels. Herein, we fabricated a novel photostimuli-responsive dual-emitting luminescent material UPTES-SPn-Tb-hfa, which was obtained by introducing the photochromic molecule spiropyran (SP) and lanthanide complex (Tb-hfa) into a siloxane-polyether matrix using the sol-gel process. Due to the conformation-dependent photochromic fluorescence resonance energy transfer between the Tb-hfa donor and SP acceptor, the ring-closing (SP)/ring-opening (MC) isomerization of the SP unit leads to a reversible luminescence switching in UPTES-SPn-Tb-hfa. This composite material has great potential for advanced anticounterfeiting because of the advantage of rapidly repeatable encryption/decryption for at least 8 times and dynamic luminescent colors within 15 s. In addition, due to its two luminescent centers (Tb3+ and MC), the luminescent color of this material can be regulated by 254 and 365 nm UV-light irradiation, which facilitates the design of multicolored anticounterfeiting labels. Our work presents a novel design methodology to fabricate dynamic anticounterfeiting materials, significantly enhancing the security of anticounterfeiting applications.

Laser Fabrication of Multi-Dimensional Perovskite Patterns with Intelligent Anti-Counterfeiting Applications.

Perovskites have gained widespread attention across various fields such as photovoltaics, displays, and imaging. Despite their promising applications, achieving precise and high-quality patterning of perovskite films remains a challenge. In this study, femtosecond laser direct writing technology is utilized to achieve rapid and highly precise micro/nanofabrication on perovskites. The study successfully fabricates multiple structured and emission-tunable perovskite patterns composed of A2(FA)n-1PbnX3n+1 (A represents a series of long-chain amine cations, and X = Cl, Br, I), encompassing 2D, quasi-2D, and 3D structures. The study delves into the intricate interplay between fabrication technology and the growth of multi-dimensional perovskites: higher repetition rates, coupled with appropriate laser power, prove more conducive to perovskite growth. By employing precise halogen element design, the simultaneous generation of two distinct color quick-response (QR) code patterns is achieved through one-step laser processing. These mirrored QR codes offer a novel approach to anti-counterfeiting. To further enhance anti-counterfeiting capabilities, artificial intelligence (AI)-based methods are introduced for recognizing patterned perovskite anti-counterfeiting labels. The combination of deep learning algorithms and a non-deterministic manufacturing process provides a convenient means of identification and creates unclonable features. This integration of materials science, laser fabrication, and AI offers innovative solutions for the future of security features.

Dynamic fluorescent patterns inspired by cuttlefish for anti-counterfeiting applications

Dynamic fluorescent patterns that convert external stimulation into intuitive color changes have drawn significant interest in various fields. However, the complex synthesis of materials with multiple emissions and technical barriers in the flexible fabrication of full-color fluorescent patterns hinder their applicability in diverse scenarios. Here, we present a bioinspired dynamic fluorescent pattern fabricated by femtosecond laser-induced forward transfer (FsLIFT), inspired by cuttlefish. The elastomeric substrate can contract and expand as muscle fibers of cuttlefish, and the patterned red, green, and blue quantum dot (QD) films can be regarded as pigment cells, achieving bionic preparation of function and morphology similar to cuttlefish. Notably, the fluorescent patterns can be modulated by manipulating strains and excitations. Using this bioinspired strategy, we successfully produced an advanced fluorescent anti-counterfeiting label via FsLIFT, which can only be recognized under specific strain and excitation light conditions. These dynamic fluorescent patterns show broad application potential in anti-counterfeiting, wearable devices, and information encryption.

Rapid Construction of PVA@CDs/SiO2 Fluorescent/Structural Color Dual-Mode Anti-Counterfeiting Labels via Spray-Coating Method.

A method of sequential spraying of polyvinyl alcohol with carbon quantum dots (PVA@CDs) aqueous suspension and SiO2 aqueous suspension is proposed to rapidly prepare multicolor dual-mode anti-counterfeiting labels. With the optimization of the concentration (15%) of colloidal microspheres in the SiO2 aqueous suspension as well as the spraying process parameters (spray distance of 10 cm, spray duration of 3 s, and assembly temperature of 20 °C), different-sized SiO2 microspheres (168 nm, 228 nm, and 263 nm) were utilized to rapidly assemble red, green, and blue photonic crystals. Furthermore, the tunable fluorescence emission of carbon quantum dots endows the labels with yellow, green, and blue fluorescence. The constructed dual-mode labeling was used to develop an anti-counterfeiting code with dual-channel information storage capabilities and also to create dual-mode multicolor anti-counterfeiting labels on various packaging substrates. This work provides a novel solution for anti-counterfeiting packaging and information storage.

Upconversion photoluminescence of the lanthanide-doped core–shell luminescent material for anti-counterfeiting recognition

Three different NaErF4:Tm@NaREF4:Er (RE = Y, Lu, Yb) core-shell luminescent material were successfully synthesized. XRD, XPS and other characterization techniques were used to analyze the composed material, morphology, and luminous characteristics of the produced microparticles. Especially, compared with the uncoated NaErF4:Tm, the luminescence intensity of the materials with active-shell structure were increased by 2.44 times, 3.46 times, and 4.01 times respectively under 980 nm laser excitation. Moreover, the generated UCMPs were reliably employed for anti-counterfeiting recognition labels when they were used as screen-printing materials for anti-counterfeiting ink.

Fast and Accurate Recognition of Perovskite Fluorescent Anti-counterfeiting Labels Based on Lightweight Convolutional Neural Networks.

Anti-counterfeiting technology has always been a key issue in the field of information security. Physical Unclonable Function (PUF) labels, which are random patterns produced by a stochastic process, emerge as an effective anti-counterfeiting strategy due to the inherent randomness of their physical patterns. In this study, we developed a high-throughput droplet array generation technique based on surface tension confinement to prepare perovskite crystal films with controllable shapes and sizes. We utilized the random distribution of perovskite nanocrystal particles to construct the PUF textures of the labels. Compared to other anti-counterfeiting labels, our labels not only possess fluorescent properties but also feature microscale dimensions (less than 5.3 × 10-2mm2), low cost (less than 3 × 10-4 USD), and high encoding capacity (1.7 × 101956), providing support for multilevel anti-counterfeiting protection. Additionally, we introduce an innovative PUF recognition method based on a Partial Convolutional Network (PaCoNet), effectively addressing the limitations of previous methods, in terms of recognition accuracy and speed. Experimental validation on a data set of perovskite nanocrystal films with up to 60 different macroscopic shapes and unique microscopic textures demonstrates that our method achieves a recognition accuracy of up to 99.65% and significantly reduces the recognition time per image to just 0.177 s, highlighting the potential application of these labels in the field of anti-counterfeiting.

Light-responsive multimode luminescence in photochromism transparent wood for anti-counterfeiting application

With the rapid development of information technology, people’s security awareness of information protection is enhanced, and the requirements for anti-counterfeiting technology have become higher and higher on different occasions. Smart materials with light stimulus response have attracted extensive attention in the development of anti-counterfeiting materials, especially next-generation intelligent transparent wood. Inspired by the color-changing behavior of plants and animals in nature, a photochromic transparent wood (PTW) composite with light-stimulated response was prepared by compounding rare earth luminescent complexes with transparent wood (TW). PTW exhibits high transmittance (85.5 %). Moreover, PTW exhibits different optical states under different light conditions, namely, colorless under sunlight and bright red fluorescence under 365-nm UV light, and the process is reversible. Additionally, PTW patterned by laser etching offered greater flexibility and personalization in terms of stimulus-response, and its information security under different light stimuli is demonstrated. Meanwhile, the PTW prepared can be applied to different products and their packaging as an invisible anti-counterfeiting label, and the storage and protection of information is realized under visible light, and the decoding of information is implemented in UV light, so as to achieve the invisible anti-counterfeiting of information. More importantly, invisible information can be clearly identified even in black packaging. The design concepts and techniques of this study provide an inspiration to combine smart responsive materials with wood-based materials to develop intelligent responsive materials, and also provides support for the subsequent design and preparation of invisible anti-counterfeiting materials.

Rare-Earth-Metal-Free Solid-State Fluorescent Carbonized-Polymer Microspheres for Unclonable Anti-Counterfeit Whispering-Gallery Emissions from Red to Near-Infrared Wavelengths.

Colloidal carbon dots (CDs) have garnered much attention as metal-free photoluminescent nanomaterials, yet creation of solid-state fluorescent (SSF) materials emitting in the deep red (DR) to near-infrared (NIR) range poses a significant challenge with practical implications. To address this challenge and to engineer photonic functionalities, a micro-resonator architecture is developed using carbonized polymer microspheres (CPMs), evolved from conventional colloidal nanodots. Gram-scale production of CPMs utilizes controlled microscopic phase separation facilitated by natural peptide cross-linking during hydrothermal processing. The resulting microstructure effectively suppresses aggregation-induced quenching (AIQ), enabling strong solid-state light emission. Both experimental and theoretical analysis support a role for extended π-conjugated polycyclic aromatic hydrocarbons (PAHs) trapped within these microstructures, which exhibit a progressive red shift in light absorption/emission toward the NIR range. Moreover, the highly spherical shape of CPMs endows them with innate photonic functionalities in combination with their intrinsic CD-based attributes. Harnessing their excitation wavelength-dependent photoluminescent (PL) property, a single CPM exhibits whispering-gallery modes (WGMs) that are emission-tunable from the DR to the NIR. This type of newly developed microresonator can serve as, for example, unclonable anti-counterfeiting labels. This innovative cross-cutting approach, combining photonics and chemistry, offers robust, bottom-up, built-in photonic functionality with diverse NIR applications.

Enhanced upconversion photoluminescence of LiYF4:Yb3+/Tb3+ crystals by introducing Mn2+ ions for efficient anti-counterfeiting recognition based on convolution neural network

A series of LiYF4:Yb3+/Tb3+ upconversion micro-particles (UCMPs) with varying Mn2+ doping concentration were prepared and examined. The composition, morphology and luminescent properties of the synthesized micro-particles was analysed by XRD, SEM, EDS and other characterization methods. Notably the significant increase of UC photoluminescence UCMPs by introducing Mn2+ ions was obtained by 980 nm laser excitation and reached the highest value as the Mn2+ ions doping concentration was 5 mol%. Furthermore, the produced UCMPs used as screen-printing materials of anti-counterfeiting ink were used for anti-counterfeiting recognition labels reliably. Moreover, based on Convolutional Neural Network (CNN), an anti-counterfeiting image recognition system was designed. The relevant research results indicate that the accuracy of the designed anti-counterfeiting image recognition system has reached 94 %, which also provides important reference significance for the application of CNN in the field of anti-counterfeiting recognition.

Lysine-mediated surface modification of cellulose nanocrystal films for multi-channel anti-counterfeiting

Utilizing advanced multiple channels for information encryption offers a powerful strategy to achieve high-capacity and highly secure data protection. Cellulose nanocrystals (CNCs) offer a sustainable resource for developing information protection materials. In this study, we present an approach that is easy to implement and adapt for the covalent attachment of various fluorescence molecules onto the surface of CNCs using the Mannich reaction in aqueous-based medium. Through the use of the Mannich reaction-based surface modification technique, we successfully achieved multi-color fluorescence in the resulting CNCs. The resulting CNC derivatives were thoroughly characterized by two dimensional heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron (XPS) spectroscopy. Notably, the optical properties of CNCs were well maintained after modification, resulting in films exhibiting blue and red structural colors. This enables the engineering of highly programmable and securely encoded anti-counterfeit labels. Moreover, subsequent coating of the modified CNCs with MXene yielded a highly secure encrypted matrix, offering advanced security and encryption capabilities under ultraviolet, visible, and near-infrared wavelengths. This CNC surface-modification enables the development of multimodal security labels with potential applications across various practical scenarios.