Optical material for security label, method for preparing the same, and security label

Abstract

The present application relates to an optical material and a preparation method thereof and a security label. The optical material provided by the present application comprises noble metal nanoparticles having a first ligand and a rare earth complex, wherein the noble metal nanoparticles are connected with the rare earth complex through the first ligand, wherein the first ligand comprises a first functional group selected from a sulfonic acid group and / or a carboxyl functional group, and one or more second functional groups selected from a mercapto group, a carboxyl group and an amino group. The present application utilizes the random characteristics of the optical material generation process to generate completely different PUF labels through the same production process. Using a laboratory-level confocal fluorescence and confocal Raman system, the optical signal intensity of the label in different areas is read at different resolutions, and digital processing is performed to form an encoding for rapid reading.

Description

Technical Field

[0001] This invention relates to the field of anti-counterfeiting ink technology, specifically to an optical material that can be used in anti-counterfeiting labels, its preparation method, and a multi-dimensional detection physically unclonable anti-counterfeiting label containing the optical material. Background Technology

[0002] Counterfeiting is a growing global problem. With the rapid development of the world economy, counterfeit currency, pharmaceuticals, food, luxury goods, and electronic products have caused incalculable losses to countries, companies, and individuals. The increasing demand for identity security and anti-counterfeiting measures is driving the application of advanced anti-counterfeiting technologies worldwide. Anti-counterfeiting labels, as the most common and convenient carrier, have seen the development of various materials for optical anti-counterfeiting labels over the past few decades, such as rare earth metal complexes, organic dyes, polymer dots, quantum dots, and supramolecular structures. Furthermore, surface-enhanced Raman scattering (SERS) labels based on heterogeneous metal nanostructures are also used as an extension of optical anti-counterfeiting due to their high signal-to-noise ratio. Traditional graphic and spectral-coded labels are typically prepared by handwriting, brushing, inkjet printing, photolithography, etc. However, due to their predictable coding patterns, these labels are easily damaged and copied. An ideal method would be universal, efficient, time- and resource-efficient, and require no expert skills or expensive reagents and equipment.

[0003] Recently, Physically Unclonable Functions (PUFs) have been explored for anti-counterfeiting due to their non-repeatable encoding methods and inherently non-deterministic code outputs generated by random processes. Their advantage lies in the fact that completely different PUF tags can be produced using identical manufacturing processes by leveraging the random characteristics of the generation process. In principle, the feasibility of a PUF tag is positively correlated with its maximum encoding capacity; that is, a PUF with a larger encoding capacity is less likely to be counterfeited, and less likely to generate two tags representing the same information in a random process. Optical PUF tags, utilizing physical processes such as chemical processes or changes of state, have a completely random generation process and excellent distinguishability at both macroscopic and microscopic levels, fully meeting the requirements for PUF manufacturing. Furthermore, their readout method is based on optical response, which is non-contact and reproducible, significantly increasing the PUF's lifespan. Secondly, their fabrication often does not require large equipment, allowing for large-scale production using the simplest methods.

[0004] Currently, most optical tags rely on various methods to form physically unclonable luminescent patterns, such as solvent evaporation, inkjet printing, spin coating annealing, and brush coating. To improve information security, fluorescent PUFs based on various material systems have been gradually proposed, including multi-level anti-counterfeiting fluorescent anti-counterfeiting tags produced using patterns generated by perovskite phase segregation and in-situ crystallization. These methods are then combined with other measurements, such as fluorescence spectroscopy, attenuation kinetics, Raman spectroscopy, and UV-Vis absorption spectroscopy. However, the production of most tags is complex in terms of manufacturing or materials. Traditional fluorescent materials suffer from drawbacks such as easy photobleaching, broad emission spectra, and difficulty in differentiation. In addition, in optical technology, surface-enhanced Raman spectroscopy (SERS) is promising in PUF systems. It originates from the surface plasmon resonance (SPR) of metal nanoparticles: the resonant coupling of electromagnetic waves with the collective oscillation of free electrons in the metal. Under the excitation of a laser of a certain wavelength, SERS can provide the chemical fingerprint spectrum of molecules adsorbed on the surface of metal nanoparticles. Compared with scattering PUF tags, SERS PUF tags have a more accurate response in each region of the reading pattern. This ability to enhance the spectrum can effectively increase the complexity of optical signals, thereby increasing coding capacity and improving anti-counterfeiting effectiveness. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes an optical material that can be used for anti-counterfeiting labels, a method for preparing the same, and a multidimensional detection physically unclonable anti-counterfeiting label containing the optical material, thereby solving the problems of complex preparation processes and low anti-counterfeiting levels in existing physically unclonable anti-counterfeiting labels.

[0006] To address the aforementioned problems, a first aspect of the present invention provides an optical material that can be used in anti-counterfeiting labels, comprising noble metal nanoparticles having a first ligand and a rare earth complex, wherein the noble metal nanoparticles are connected to the rare earth complex via the first ligand, wherein the first ligand comprises a first functional group selected from sulfonic acid groups and / or carboxyl groups and one or more second functional groups selected from mercapto, carboxyl, and amino groups.

[0007] In some embodiments, the first ligand is selected from one or more compounds of Formula I.

[0008]

[0009] In Formula I, R1 is selected from mercapto, carboxyl, or amino groups, M1 is selected from hydrogen or alkali metals, and L is selected from... L1 is selected from straight-chain alkylene groups of C1-C20 or branched alkylene groups of C3-C20, preferably from straight-chain alkylene groups of C3-C15, and more preferably from straight-chain alkylene groups of C6-C15.

[0010] In some embodiments, the first ligand is selected from one or more compounds of formula I-1 or formula I-2.

[0011]

[0012] In the formula, R1 is selected from mercapto, carboxyl or amino, M1 is selected from hydrogen or alkali metal, and L1 is selected from C1-C20 straight-chain alkylene or C3-C20 branched alkylene, preferably from C3-C15 straight-chain alkylene, more preferably from C6-C15 straight-chain alkylene.

[0013] In some embodiments, M1 in the above formula is selected from hydrogen, lithium, sodium, or potassium.

[0014] In some embodiments, L1 is selected from straight-chain alkylene groups of C1-C6, straight-chain alkylene groups of C7-C15, straight-chain alkylene groups of C16-C20, branched alkylene groups of C3-C6, branched alkylene groups of C7-C15, and branched alkylene groups of C16-C20.

[0015] In some embodiments, L1 is selected from n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, or n-pentadecanylene.

[0016] In some embodiments, the first ligand is selected from one or more of sodium 9-mercaptononanesulfonate, sodium 10-mercaptodecanesulfonate, sodium 11-mercaptoundecanesulfonate, sodium 12-mercaptododecanesulfonate, sodium 13-mercaptotridecanesulfonate, sodium 9-mercaptononane acid, sodium 10-mercaptodecane acid, sodium 11-mercaptoundecane acid, sodium 12-mercaptododecane acid, or sodium 13-mercaptotridecane acid.

[0017] In some embodiments, the noble metal nanoparticles are selected from one or more of gold nanoparticles, silver nanoparticles, and platinum nanoparticles.

[0018] In some embodiments, the particle size of the noble metal nanoparticles is 5nm-200nm, for example, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 60nm, 60nm, 70nm, 80nm, 90nm, 100nm, 100nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or any value between them.

[0019] In some embodiments, the particle size of the noble metal nanoparticles is 20nm-50nm.

[0020] In some embodiments, the rare earth complex is selected from one or more europium complexes and terbium complexes.

[0021] In some embodiments, the rare earth complex is selected from rare earth metal salts and second ligands to form a complex, wherein the rare earth metal salt is selected from europium salts and / or terbium salts, and the second ligand is selected from β-diketone ligands with cationic groups.

[0022] In some embodiments, the second ligand is selected from one or more compounds of formula II:

[0023]

[0024] In Formula II, L2 is selected from C1-C20 straight-chain alkylene, C3-C20 branched alkylene, C6-C20 aryl, C1-C20 straight-chain alkoxy-substituted phenylene, C3-C20 branched alkoxy-substituted phenylene, C1-C20 straight-chain alkyl-substituted carbazolyl, and C3-C20 branched alkyl-substituted carbazolyl.

[0025] M2 is selected from hydroxyl or halogen;

[0026] R2 is selected from C1-C6 straight-chain alkyl, C3-C6 branched alkyl, halogenated C1-C6 straight-chain alkyl, halogenated C3-C6 branched alkyl, and C6-C12 aryl.

[0027] R3, R4, and R5 may be the same or different, and each is independently selected from C1-C6 straight-chain alkyl or C3-C6 branched-chain alkyl.

[0028] In some embodiments, L2 is selected from C3-C15 linear alkylene groups, C3-C15 linear alkoxy-substituted phenyl groups, and C3-C15 linear alkyl-substituted carbazolyl groups.

[0029] In some embodiments, L2 is selected from C1-C6 straight-chain alkylene, C7-C15 straight-chain alkylene, and C16-C20 straight-chain alkylene, such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, or n-pentadecanylene.

[0030] In some embodiments, L2 is selected from the following groups:

[0031]

[0032] Preferably, L2 is selected from the following groups:

[0033]

[0034] in, Connected to the diketone end, -* connects to the ammonium end;

[0035] a is an integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19;

[0036] a is an integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19.

[0037] In some embodiments, M2 is selected from hydroxyl, fluorine, chlorine, bromine or iodine.

[0038] In some embodiments, R2 is selected from fluoromethyl, fluoroethyl, fluoron-propyl, fluoroisopropyl, fluoron-butyl, fluoroisobutyl, fluorotert-butyl, phenyl, or naphthyl.

[0039] In some embodiments, R2 is selected from trifluoromethyl, phenyl, or naphthyl.

[0040] In some embodiments, R3, R4, and R5 may be the same or different, and each may be independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl.

[0041] In some implementations... Selected from the following structures:

[0042]

[0043] In some embodiments, the second ligand is selected from N,N,N-trimethyl-2-(3-(4,4,4-trifluoro-3-oxobutyryl)-9H-carbazole-9-yl)ethyl-1-ammonium and / or N,N,N-trimethyl-3-(4-(3-oxo-3-phenylpropionyl)phenoxy)propaneammonium.

[0044] In some embodiments, the rare earth metal salt is selected from one or more of europium nitrate, europium hydrochloride, europium sulfate, terbium nitrate, terbium hydrochloride, or terbium sulfate.

[0045] In this invention, the end groups of the first ligand connected to the surface of the noble metal nanoparticle include thiol, carboxyl and amino groups, that is, the connection between the ligand and the noble metal nanoparticle is achieved through the interaction forces between the noble metal and sulfur, oxygen and nitrogen.

[0046] The end groups of the first ligand connected to the rare earth complex include sulfonic acid groups and / or carboxyl groups, that is, they are connected to the rare earth complex through electrostatic interaction.

[0047] In a second aspect, the present invention provides an optical material that can be used in anti-counterfeiting labels, the optical material comprising a reaction product of noble metal nanoparticles, rare earth complexes, and a first ligand.

[0048] In some embodiments, the first ligand is selected from one or more compounds of Formula I.

[0049]

[0050] In Formula I, R1 is selected from mercapto, carboxyl, or amino groups, M1 is selected from hydrogen or alkali metals, and L is selected from... L1 is selected from straight-chain alkylene groups of C1-C20 or branched alkylene groups of C3-C20, preferably from straight-chain alkylene groups of C3-C15, and more preferably from straight-chain alkylene groups of C6-C15.

[0051] In some embodiments, the first ligand is selected from one or more compounds of formula I-1 or formula I-2.

[0052]

[0053] In the formula, R1 is selected from mercapto, carboxyl or amino, M1 is selected from hydrogen or alkali metal, and L1 is selected from C1-C20 straight-chain alkylene or C3-C20 branched alkylene, preferably from C3-C15 straight-chain alkylene, more preferably from C6-C15 straight-chain alkylene.

[0054] In some embodiments, M1 in the above formula is selected from hydrogen, lithium, sodium, or potassium.

[0055] In some embodiments, L1 is selected from straight-chain alkylene groups of C1-C6, straight-chain alkylene groups of C7-C15, straight-chain alkylene groups of C16-C20, branched alkylene groups of C3-C6, branched alkylene groups of C7-C15, and branched alkylene groups of C16-C20.

[0056] In some embodiments, L1 is selected from n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, or n-pentadecanylene.

[0057] In some embodiments, the first ligand is selected from one or more of sodium 9-mercaptononanesulfonate, sodium 10-mercaptodecanesulfonate, sodium 11-mercaptoundecanesulfonate, sodium 12-mercaptododecanesulfonate, sodium 13-mercaptotridecanesulfonate, sodium 9-mercaptononane acid, sodium 10-mercaptodecane acid, sodium 11-mercaptoundecane acid, sodium 12-mercaptododecane acid, or sodium 13-mercaptotridecane acid.

[0058] In some embodiments, the noble metal nanoparticles are selected from one or more of gold nanoparticles, silver nanoparticles, and platinum nanoparticles.

[0059] In some embodiments, the particle size of the noble metal nanoparticles is 5nm-200nm, for example, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 60nm, 60nm, 70nm, 80nm, 90nm, 100nm, 100nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or any value between them.

[0060] In some embodiments, the particle size of the noble metal nanoparticles is 20nm-50nm.

[0061] In some embodiments, the rare earth complex is selected from one or more europium complexes and terbium complexes.

[0062] In some embodiments, the rare earth complex is selected from rare earth metal salts and second ligands to form a complex, wherein the rare earth metal salt is selected from europium salts and / or terbium salts, and the second ligand is selected from β-diketone ligands with cationic groups.

[0063] In some embodiments, the second ligand is selected from one or more compounds of formula II:

[0064]

[0065] In Formula II, L2 is selected from C1-C20 straight-chain alkylene, C3-C20 branched alkylene, C6-C20 aryl, C1-C20 straight-chain alkoxy-substituted phenylene, C3-C20 branched alkoxy-substituted phenylene, C1-C20 straight-chain alkyl-substituted carbazolyl, and C3-C20 branched alkyl-substituted carbazolyl.

[0066] M2 is selected from hydroxyl or halogen;

[0067] R2 is selected from C1-C6 straight-chain alkyl, C3-C6 branched alkyl, halogenated C1-C6 straight-chain alkyl, halogenated C3-C6 branched alkyl, and C6-C12 aryl.

[0068] R3, R4, and R5 may be the same or different, and each is independently selected from C1-C6 straight-chain alkyl or C3-C6 branched-chain alkyl.

[0069] In some embodiments, L2 is selected from C3-C15 linear alkylene groups, C3-C15 linear alkoxy-substituted phenyl groups, and C3-C15 linear alkyl-substituted carbazolyl groups.

[0070] In some embodiments, L2 is selected from C1-C6 straight-chain alkylene, C7-C15 straight-chain alkylene, and C16-C20 straight-chain alkylene, such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, or n-pentadecanylene.

[0071] In some embodiments, L2 is selected from the following groups:

[0072]

[0073] Preferably, L2 is selected from the following groups:

[0074]

[0075] in, Connected to the diketone end, -* connects to the ammonium end;

[0076] a is an integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19;

[0077] a is an integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19.

[0078] In some embodiments, M2 is selected from hydroxyl, fluorine, chlorine, bromine or iodine.

[0079] In some embodiments, R2 is selected from fluoromethyl, fluoroethyl, fluoron-propyl, fluoroisopropyl, fluoron-butyl, fluoroisobutyl, fluorotert-butyl, phenyl, or naphthyl.

[0080] In some embodiments, R2 is selected from trifluoromethyl, phenyl, or naphthyl.

[0081] In some embodiments, R3, R4, and R5 may be the same or different, and each may be independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl.

[0082] In some implementations... Selected from the following structures:

[0083]

[0084] In some embodiments, the second ligand is selected from N,N,N-trimethyl-2-(3-(4,4,4-trifluoro-3-oxobutyryl)-9H-carbazole-9-yl)ethyl-1-ammonium and / or N,N,N-trimethyl-3-(4-(3-oxo-3-phenylpropionyl)phenoxy)propaneammonium.

[0085] In some embodiments, the rare earth metal salt is selected from one or more of europium nitrate, europium hydrochloride, europium sulfate, terbium nitrate, terbium hydrochloride, or terbium sulfate.

[0086] A third aspect of the present invention provides an anti-counterfeiting ink, which includes the optical material and solvent described in the first or second aspect.

[0087] In some embodiments, the solvent is selected from water and C1-C6 monohydric alcohols, such as methanol and / or ethanol.

[0088] In some embodiments, the solvent consists of methanol and water.

[0089] A fourth aspect of the present invention provides a method for preparing an optical material or anti-counterfeiting ink that can be used in anti-counterfeiting labels, comprising:

[0090] S1: A first solution containing a noble metal salt is reacted with a second solution containing a first ligand to obtain a first reaction product containing the first ligand;

[0091] S2: The first reaction product containing the first ligand is reacted with a third solution including a reducing agent to obtain noble metal nanoparticles containing the first ligand.

[0092] S3: Mix noble metal nanoparticles with the first ligand and rare earth complexes in a solvent.

[0093] In some embodiments, the first ligand is selected from one or more compounds of Formula I.

[0094]

[0095] In Formula I, R1 is selected from mercapto, carboxyl, or amino groups, M1 is selected from hydrogen or alkali metals, and L is selected from... L1 is selected from straight-chain alkylene groups of C1-C20 or branched alkylene groups of C3-C20, preferably from straight-chain alkylene groups of C3-C15, and more preferably from straight-chain alkylene groups of C6-C15.

[0096] In some embodiments, the first ligand is selected from one or more compounds of formula I-1 or formula I-2.

[0097]

[0098] In the formula, R1 is selected from mercapto, carboxyl or amino, M1 is selected from hydrogen or alkali metal, and L1 is selected from C1-C20 straight-chain alkylene or C3-C20 branched alkylene, preferably from C3-C15 straight-chain alkylene, more preferably from C6-C15 straight-chain alkylene.

[0099] In some embodiments, M1 in the above formula is selected from hydrogen, lithium, sodium, or potassium.

[0100] In some embodiments, L1 is selected from straight-chain alkylene groups of C1-C6, straight-chain alkylene groups of C7-C15, straight-chain alkylene groups of C16-C20, branched alkylene groups of C3-C6, branched alkylene groups of C7-C15, and branched alkylene groups of C16-C20.

[0101] In some embodiments, L1 is selected from n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, or n-pentadecanylene.

[0102] In some embodiments, the first ligand is selected from one or more of sodium 9-mercaptononanesulfonate, sodium 10-mercaptodecanesulfonate, sodium 11-mercaptoundecanesulfonate, sodium 12-mercaptododecanesulfonate, sodium 13-mercaptotridecanesulfonate, sodium 9-mercaptononane acid, sodium 10-mercaptodecane acid, sodium 11-mercaptoundecane acid, sodium 12-mercaptododecane acid, or sodium 13-mercaptotridecane acid.

[0103] In some embodiments, the noble metal nanoparticles are selected from one or more of gold nanoparticles, silver nanoparticles, and platinum nanoparticles.

[0104] In some embodiments, the particle size of the noble metal nanoparticles is 5nm-200nm, for example, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 60nm, 60nm, 70nm, 80nm, 90nm, 100nm, 100nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or any value between them.

[0105] In some embodiments, the particle size of the noble metal nanoparticles is 20nm-50nm.

[0106] In some embodiments, the rare earth complex is selected from one or more europium complexes and terbium complexes.

[0107] In some embodiments, the rare earth complex is selected from rare earth metal salts and second ligands to form a complex, wherein the rare earth metal salt is selected from europium salts and / or terbium salts, and the second ligand is selected from β-diketone ligands with cationic groups.

[0108] In some embodiments, the second ligand is selected from one or more compounds of formula II:

[0109]

[0110] In Formula II, L2 is selected from C1-C20 straight-chain alkylene, C3-C20 branched alkylene, C6-C20 aryl, C1-C20 straight-chain alkoxy-substituted phenylene, C3-C20 branched alkoxy-substituted phenylene, C1-C20 straight-chain alkyl-substituted carbazolyl, and C3-C20 branched alkyl-substituted carbazolyl.

[0111] M2 is selected from hydroxyl or halogen;

[0112] R2 is selected from C1-C6 straight-chain alkyl, C3-C6 branched alkyl, halogenated C1-C6 straight-chain alkyl, halogenated C3-C6 branched alkyl, and C6-C12 aryl.

[0113] R3, R4, and R5 may be the same or different, and each is independently selected from C1-C6 straight-chain alkyl or C3-C6 branched-chain alkyl.

[0114] In some embodiments, L2 is selected from C3-C15 linear alkylene groups, C3-C15 linear alkoxy-substituted phenyl groups, and C3-C15 linear alkyl-substituted carbazolyl groups.

[0115] In some embodiments, L2 is selected from C1-C6 straight-chain alkylene, C7-C15 straight-chain alkylene, and C16-C20 straight-chain alkylene, such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, or n-pentadecanylene.

[0116] In some embodiments, L2 is selected from the following groups:

[0117]

[0118] Preferably, L2 is selected from the following groups:

[0119]

[0120] in, Connected to the diketone end, -* connects to the ammonium end;

[0121] a is an integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19;

[0122] a is an integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19.

[0123] In some embodiments, M2 is selected from hydroxyl, fluorine, chlorine, bromine or iodine.

[0124] In some embodiments, R2 is selected from fluoromethyl, fluoroethyl, fluoron-propyl, fluoroisopropyl, fluoron-butyl, fluoroisobutyl, fluorotert-butyl, phenyl, or naphthyl.

[0125] In some embodiments, R2 is selected from trifluoromethyl, phenyl, or naphthyl.

[0126] In some embodiments, R3, R4, and R5 may be the same or different, and each may be independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl.

[0127] In some implementations... Selected from the following structures:

[0128]

[0129] In some embodiments, the second ligand is selected from N,N,N-trimethyl-2-(3-(4,4,4-trifluoro-3-oxobutyryl)-9H-carbazole-9-yl)ethyl-1-ammonium and / or N,N,N-trimethyl-3-(4-(3-oxo-3-phenylpropionyl)phenoxy)propaneammonium.

[0130] In some embodiments, the rare earth metal salt is selected from one or more of europium nitrate, europium hydrochloride, europium sulfate, terbium nitrate, terbium hydrochloride, or terbium sulfate.

[0131] In some embodiments, in step S1, the solvent of the first solution is selected from C1-C6 monohydric alcohols, preferably one or more of methanol, ethanol and isopropanol.

[0132] In some embodiments, in step S1, the noble metal salt is selected from one or more of gold chloride trihydrate, silver trifluoromethanesulfonate, silver nitrate, and hexachloroplatinic acid.

[0133] In some embodiments, in step S1, the solvent of the second solution is selected from C1-C6 monohydric alcohols, preferably one or more of methanol, ethanol and isopropanol.

[0134] In some embodiments, in step S2, the solvent of the third solution is selected from C1-C6 monohydric alcohols, preferably one or more of methanol, ethanol and isopropanol.

[0135] In some embodiments, in step S2, the reducing agent is selected from sodium borohydride or borane-tert-butylamine.

[0136] In some embodiments, in step S2, the first reaction product and the third solution are mixed by adding a third solution dropwise to the first reaction product before the reaction proceeds. In some embodiments, the dropwise addition time is 0.5-2 hours, for example, 1 hour or 1.5 hours.

[0137] In some embodiments, step S3, the preparation of the rare earth complex includes: reacting a fourth solution including the second ligand with a rare earth metal salt to obtain a reaction product, and then performing solid-liquid separation on the reaction product to obtain the rare earth complex.

[0138] In some embodiments, the solvent of the fourth solution is selected from C1-C6 monohydric alcohols, preferably one or more of methanol, ethanol, and isopropanol.

[0139] In some embodiments, in step S1, the molar ratio of the noble metal salt to the first ligand, calculated as a noble metal, is from 1:0.5 to 1:5, for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, or 1:4.5. In some embodiments, the molar ratio of the noble metal salt to the first ligand is from 1:1 to 1:3.

[0140] In some embodiments, in step S1, the time for the first reaction is 5 min to 90 min, for example, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, or 80 min. In some embodiments, in step S1, the time for the first reaction is 15 min to 60 min.

[0141] In some embodiments, in step S1, the temperature of the first reaction is 5°C-30°C, for example, 10°C, 15°C, 20°C, or 25°C. In some embodiments, in step S1, the temperature of the first reaction is room temperature.

[0142] In some embodiments, in step S2, the molar ratio of the precious metal salt to the reducing agent, calculated as a precious metal, is from 1:3 to 1:50, for example, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, or 1:45. In some embodiments, the molar ratio of the precious metal salt to the reducing agent is from 1:10 to 1:30.

[0143] In some embodiments, in step S2, the time for the second reaction is 0.5h-5h, for example, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, or 1.5h. In some embodiments, the time for the second reaction is 1h-3h.

[0144] In some embodiments, in step S2, the temperature of the second reaction is 5°C-30°C, for example, 10°C, 15°C, 20°C, or 25°C. In some embodiments, in step S2, the temperature of the second reaction is room temperature.

[0145] In some embodiments, in step S3, the molar ratio of the noble metal nanoparticles to the rare earth complex is 1 mg:(0.001-0.01) mmol, for example, 1 mg:0.002 mmol, 1 mg:0.003 mmol, 1 mg:0.004 mmol, 1 mg:0.005 mmol, 1 mg:0.006 mmol, 1 mg:0.007 mmol, 1 mg:0.008 mmol, or 1 mg:0.009 mmol. In some embodiments, the molar ratio of the noble metal nanoparticles to the rare earth complex is 1 mg:(0.003-0.08) mmol.

[0146] In some embodiments, in step S3, the mass-to-solvent volume ratio of the noble metal nanoparticles is 1-5 mg / mL, for example, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4 mg / mL, or 4.5 mg / mL. In some embodiments, the mass-to-solvent volume ratio of the noble metal nanoparticles is 2-3 mg / mL.

[0147] In some embodiments, in step S3, the volume ratio of the rare earth complex to the solvent is 1-5 mg / mL, for example, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4 mg / mL, or 4.5 mg / mL. In some embodiments, the volume ratio of the rare earth complex to the solvent is 2-3 mg / mL.

[0148] In some embodiments, the mixing in step S3 is performed under ultrasonic conditions. In some embodiments, the ultrasonic treatment lasts for 10-30 minutes.

[0149] In some embodiments, the molar ratio of the rare earth metal salt to the second ligand is from 1:0.1 to 1:3, for example, 1:0.5, 1:1, 1:1.5, 1:2 or 1:2.5.

[0150] In some embodiments, the fourth reaction takes place over a period of 3 to 24 hours, for example, 6 hours, 9 hours, 12 hours, 15 hours, or 20 hours. In some embodiments, the fourth reaction takes place over a period of 30°C to 70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, or 65°C.

[0151] In some embodiments, the preparation of the anti-counterfeiting ink includes the following specific steps:

[0152] Step 1: In a 500 mL round-bottom flask, dissolve 0.2–0.8 mmol of silver trifluoromethanesulfonate in 100 mL of ethanol, then stir with a magnetic rod at 800 rpm on a stirring plate. Ensure the gold salt is completely dissolved. Weigh or measure an amount of surfactant equal to the silver salt and dissolve in 10 mL of methanol. Weigh 2–8 mmol of sodium borohydride and add it to 100–300 mL of ethanol, stirring vigorously with a magnetic stirrer (600–800 rpm) until dissolved. Once NaBH4 is dissolved in ethanol, begin filtering the solution through filter paper into a adding funnel. Add the ligand solution to the reaction mixture. Wait 15 minutes for the silver-sulfur complex to form. Begin adding the filtered NaBH4 solution dropwise from the adding funnel. Adjust the dropping interval so that the addition of NaBH4 takes approximately 1 hour. After all NaBH4 has been added, remove the funnel. Continue stirring the reaction for one hour. At the end of the reaction, remove the magnetic stir bar using a magnet placed outside the flask. Close the flask with a septum and insert a needle into the septum to release the H2 gas produced after the reaction. Store the reaction mixture in a laboratory refrigerator (4°C) overnight to allow the nanoparticles to precipitate.

[0153] Step 2: Dissolve 3 mmol of N,N,N-trimethyl-2-(3-(4,4,4-trifluoro-3-oxobutyryl)-9H-carbazole-9-yl)ethyl-1-ammonium in 5 ml of methanol. Adjust the pH of the solution to 8.0 with 3 ml of 1 M NaOH to obtain a clear solution. Then add 1 mmol (0.446 g) of Eu(NO3)3·6H2O to the above solution to form a pale yellow turbid solution. Stir at 60 °C for 12 h. After filtration, wash repeatedly with water and ethanol, and dry under vacuum to obtain Eu(THB)3.

[0154] Step 3: Dissolve 10 mg of silver nanoparticles in 5 mL of methanol solution and add a certain amount of Eu(THB)3. Immediately after adding Eu(THB)3, begin the assembly process, centrifuge at 3000 rpm-10000 rpm for 5 minutes, pour into the solution, and then wash with methanol until the solution shows no red light under ultraviolet light.

[0155] The fifth aspect of this invention provides the application of the optical materials or anti-counterfeiting inks prepared by the first or second aspect, the third aspect, or the fourth aspect in anti-counterfeiting, such as in the anti-counterfeiting of product packaging or tickets.

[0156] The sixth aspect of the present invention provides an unclonable anti-counterfeiting label, which includes a substrate layer, a protective layer, and an anti-counterfeiting layer located between the substrate layer and the protective layer, wherein the anti-counterfeiting layer is formed from the optical material described in the first or second aspect or from the anti-counterfeiting ink described in the third aspect or the preparation method described in the third aspect.

[0157] In some embodiments, the method for preparing the non-cloneable anti-counterfeiting label includes: dropping the anti-counterfeiting ink onto the substrate layer, allowing the anti-counterfeiting ink to evaporate and dry to obtain an anti-counterfeiting layer, and then covering the anti-counterfeiting layer with the protective layer.

[0158] In some embodiments, the substrate layer is selected from glass and / or plastic.

[0159] In some embodiments, the area of ​​the substrate layer is 1 mm. 2 -25mm 2 Preferably 4mm 2 -9mm 2 .

[0160] The seventh aspect of the present invention provides a method for identifying anti-counterfeiting labels, which includes placing the non-clonable anti-counterfeiting label described in the sixth aspect in a confocal system to obtain an intensity mapping image, acquiring data in the image and performing digital processing to form anti-counterfeiting coding information, wherein the confocal system includes confocal fluorescence, confocal lifetime and confocal Raman.

[0161] In some embodiments, the method includes irradiating the non-clonable anti-counterfeiting label under confocal fluorescence, confocal lifetime, and confocal Raman lasers respectively to obtain intensity mapping images.

[0162] In some implementations, the data is pixel location information, where each pixel represents fluorescence intensity, fluorescence wavelength, fluorescence lifetime, Raman wavelength, and Raman intensity at the same location on the substrate.

[0163] In some implementations, when using a confocal system to analyze information on anti-counterfeiting labels, intensity information is obtained from appropriate peaks in fluorescence spectroscopy, Raman spectroscopy, and lifetime spectroscopy; when using two or more detection methods, different information contained in the same orthogonal pixel is selected.

[0164] In some implementations, the digitization process includes data preprocessing and digitization of the data obtained from the image.

[0165] In some implementations, the data preprocessing involves filtering out some noise from the Raman signal information and removing background signals.

[0166] In some implementations, the digitization involves normalizing and segmenting the fluorescence intensity, Raman intensity, and fluorescence lifetime using testing software to form relative signal intensities; and combining the position information of each pixel with the signal intensity information to form anti-counterfeiting coding information.

[0167] In some implementations, the digitization includes the following steps:

[0168] a. Normalize the intensity values ​​of each fluorescence intensity, Raman signal, and lifetime signal, and quantize the signal intensity value of each pixel;

[0169] b. Combining the position information of each pixel, the different signal intensities after segmentation are used to form anti-counterfeiting coding information;

[0170] c. Conduct repeatability tests to obtain more accurate labeling results. Compare the data obtained from the repeat tests to verify the reliability of the label test. If the test is successful, transfer the data to the database.

[0171] In some embodiments, the anti-counterfeiting label identification method further includes verification, which involves using other confocal devices to collect anti-counterfeiting pattern information and comparing it with data in the database. If a single confocal device is used for collection, the information is compared with the corresponding database information. If two or more confocal devices are used for collection, the information is compared with relevant or all database information.

[0172] In some embodiments, the identification method includes:

[0173] 1) Irradiate the non-clonable anti-counterfeiting label under a 400nm laser for testing fluorescence intensity and fluorescence lifetime;

[0174] 2) Irradiate the non-clonable anti-counterfeiting label under a 532nm or 785nm laser for Raman intensity testing;

[0175] For the confocal fluorescence system, a 400nm laser and a 100x objective lens are used to test the light in the 590nm-650nm channel. The image is segmented, and signals at different pixel resolutions are read. The average luminous intensity signal of each region is read to form the PUF tag signal.

[0176] For the confocal Raman system, a 785nm laser and a 100× objective lens were used to test the Raman signal, and the Raman mapping intensity of different pixels was obtained by surface scanning at different pixel resolutions.

[0177] For the confocal lifetime system, a 400nm laser and a 100x objective lens were used to test the material lifetime in this region, and then an overall fit was performed. The fitted image was segmented according to different pixel resolutions to read the signals, and the average lifetime signal of each region was read separately to form the PUF tag signal.

[0178] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0179] 1) This invention presents a physically non-clonable anti-counterfeiting label based on the electrostatic self-assembly of negatively charged metal nanoparticles, such as silver nanoparticles, and positively charged rare earth complexes. The label is loaded with hydrophilic ligands with sulfonate groups and / or carboxyl groups at the end through noble metal-thiol chemical reaction. The use of sulfonate groups compared to carboxylate groups can ensure the maximum degree of deprotonation.

[0180] 2) Because rare earth ions have a high coordination number, they can coordinate with multiple quaternary ammonium salt ligands, making it easy to synthesize multi-positively charged rare earth complexes.

[0181] 3) During the assembly process, the rare earth complex itself acts as the luminescent center, and also as the "glue" for noble metals such as AgNPs to achieve assembly; AgNPs, on the other hand, act as "hot spots" to enhance the light field intensity near its surface, including the luminescence and Raman spectrum of the rare earth complex.

[0182] 4) The anti-counterfeiting label of this invention is made by mixing two materials and then dripping them onto the substrate surface. After the solvent evaporates, the disordered distribution of the assembly at the nanoscale and the randomness of the resulting pattern make the label impossible to counterfeit. Using a laboratory-grade confocal fluorescence and confocal Raman system, the optical signal intensity of the label in different areas is read at different resolutions, and digital processing is performed to form an encoding for rapid reading.

[0183] 5) The anti-counterfeiting label of the present invention carries fluorescence, Raman spectrum, fluorescence lifetime and graphic information at the same time, which increases the information capacity, improves the security level, and can also realize corresponding specific detection in specific scenarios, thus broadening the application channels. Attached Figure Description

[0184] Figure 1 The fluorescence spectra of the rare earth complex (Eu(THB)3) and physically unclonable ink (Ag-aggregation) prepared in Example 1 of this invention are shown.

[0185] Figure 2 The lifetime spectra of the rare earth complex and physically unclonable ink prepared in Example 1 of this invention are shown.

[0186] Figure 3 Raman spectra of the rare earth complex and physically unclonable ink prepared in Example 1 of this invention.

[0187] Figure 4 The manufacturing and readout steps of the physically unclonable ink on the substrate prepared in Embodiment 1 of the present invention are shown.

[0188] Figure 5 The image shows the binary code, quaternary code, and quaternary code three-dimensional diagram of the tag prepared in Embodiment 1 of the present invention. Detailed Implementation

[0189] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0190] Preparation of sodium 11-thiol sulfonate

[0191] 11-Bromo-1-Undecene (25 mL, 111.975 mmol), sodium sulfite (28.75 g, 227.92 mmol), and benzyltriethylammonium bromide (10 mg) were added to a mixture of 200 mL methanol (MeOH) and 450 mL deionized water (4:9 v / v MeOH:H2O), and the mixture was placed in a 1 L round-bottom flask. The reaction mixture was refluxed at 102 °C for 48 hours.

[0192] Connect the reaction mixture to a rotary evaporator to evaporate the MeOH, reducing the volume to approximately 300 mL. Transfer the remaining solution to a 1 L separatory funnel. Using an addition funnel, extract the remaining aqueous solution five times with diethyl ether. Separate the unreacted 11-bromo-1-undecene remaining in the ether phase and the sulfonated product in H₂O.

[0193] Collect the final extracted aqueous solution into a 1 L single-necked round-bottom flask. Connect the reaction flask to a rotary evaporator to evaporate the aqueous phase. Connect the flask to a high vacuum chamber to directly dry the white powder. Keep the flask in a vacuum bath at 60 °C and leave it overnight.

[0194] Suspend the white powder in 400 mL of methanol in a flask. Sonicate to dissolve the product to maximize solubility. To further increase solubility, the methanol can be gently heated to near its boiling point (~64°C).

[0195] Filter the solution to remove methanol-insoluble inorganic byproducts. Transfer the filtered solution from the filter flask to a 1L round-bottom flask. Connect the flask to a rotary evaporator and evaporate the methanol solution at 45°C, redissolving the white powder in methanol and filtering the solution. Repeat this process at least twice to reduce the inorganic salt content. Sodium 11-en-undecanesulfonate is obtained.

[0196] Dissolve 30 g of sodium 11-en-undecanesulfonate and an initiator dose of azobisisobutyronitrile in 500 ml of methanol and place the solution in a 1 L round-bottom flask. Under anhydrous and oxygen-free conditions, add 2.6 equivalents of thioacetic acid to the solution and initiate the reaction at 55 °C for 12 h.

[0197] Evaporate all MeOH in a rotary evaporator until the solid residue turns orange-red. Using a filter flask, wash the product with petroleum ether to remove any excess thioacetic acid until no colored (orange-yellow) substance appears in the petroleum ether supernatant. Dry the solid under high vacuum and then dissolve it in methanol to produce a yellow to orange solution. Add 3 grams of carbon black to the solution, mix vigorously, and filter to obtain a clear solution. Completely evaporate the solvent in a rotary evaporator, collecting approximately 35 grams of white powder to give sodium 11-acetylthioundecanesulfonate.

[0198] Sodium 11-acetylthioundecanesulfonate was refluxed in 400 mL of 1M HCl at 102 °C for 12 hours to cleave the thioacetic acid group, yielding mercaptool. The reaction flask was connected to a rotary evaporator to evaporate the aqueous phase. When less than 100 mL of solution had evaporated, the mixture was cooled to allow the product to crystallize. Centrifugation yielded the final product, sodium 11-thiol sulfonate (sodium 11-mercaptoundecanesulfonate).

[0199] Preparation of ligand N,N,N-trimethyl-2-(3-(4,4,4-trifluoro-3-oxobutyryl)-9H-carbazole-9-yl)ethyl-1-ammonium (compound 4)

[0200]

[0201] Synthesis of Compound 1:

[0202] Carbazole (0.1M, 16.72g), 2-chloro-N,N-dimethylethylenediamine hydrochloride (0.15M, 21.45g), sodium hydride (0.2M, 8g), and 100mL of DMF were added to a 250mL round-bottom flask, and the mixture was stirred in an oil bath at 100°C for 24 hours. After the reaction was complete, the solvent was removed by rotary evaporation, the organic phase was extracted with dichloromethane, and washed three times with saturated brine. The product was dried over anhydrous magnesium sulfate and then rotary evaporated to give a brown oily substance. The crude product was subjected to column chromatography using dichloromethane and methanol (20:1-10:1) as eluents to give purified product 1. Yield: 80%. Rf value: 0.27 (ethyl acetate:methanol = 7 / 1, v / v).

[0203] 1 H NMR(400MHz,Chloroform-d)δ8.14(d,J=7.8Hz,2H),7.55–7.48(m,2H),7.45(s,2H ),7.29(dd,J=11.5,4.6Hz,2H),4.51–4.34(m,2H),2.79–2.69(m,2H),2.40(s,6H).

[0204] Synthesis of compound 2:

[0205] Compound 1 (10 mmol, 2.38 g) was dissolved in 30 mL of anhydrous dichloromethane, and then anhydrous aluminum trichloride (15 mmol, 2.0 g) was slowly added under ice bath conditions (0 °C). Chloroacetyl (10 mmol, 0.785 g), already dissolved in 20 mL of dry dichloromethane, was slowly added dropwise to the reaction system using a constant pressure funnel. The ice bath was removed and the mixture was stirred at room temperature. The reaction progress was monitored using thin-layer chromatography (eluent: dichloromethane / methanol, v / v = 10:1). After the reactants had completely reacted, the reaction was quenched with 1.0 M dilute hydrochloric acid. The product was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, and rotary evaporated to obtain an oily substance. The crude product was subjected to column chromatography using dichloromethane as the eluent. Yield: 48%. Rf value: 0.27 (dichloromethane:methanol = 7 / 1, v / v).

[0206] 1 H NMR (400MHz, CDCl3) δ8.49(s,1H),7.98(t,J=7.4Hz,2H),7.62(t,J=9.5Hz,2H),7.47(d,J=7.4Hz ,1H),7.25(t,J=7.4Hz,1H),4.90(s,2H),3.45(dd,J=8.0,4.0Hz,2H),2.91(s,6H),2.57(s,3H).

[0207] Synthesis of compound 3:

[0208] Compound 2 (3.2 mmol, 0.894 g) was dissolved in 20 mL of a mixed solvent of tert-butanol and tetrahydrofuran (v / v = 1:1). Potassium tert-butoxide (18.75 mmol, 2.1 g) was then slowly added in an ice bath, and the mixture was stirred at 0 °C for 15 min. Subsequently, ethyl trifluoroacetate (3.7 mL, 30 mmol, 4.4 g) was added, and the mixture was stirred at room temperature for 24 h. The product was extracted with dichloromethane, washed with saturated brine, dried over anhydrous magnesium sulfate, and then rotary evaporated to form a white solid. The crude product was subjected to column chromatography using dichloromethane and methanol (v / v, 20:1) as eluents. Yield: 46%. Rf value: 0.31 (dichloromethane / methanol = 10 / 1, v / v).

[0209] 1 H NMR(400MHz,)δ8.59(d,J=1.5Hz,1H),8.23(d,J=7.8Hz,1H),7.95(dd,J=8.6,1.6Hz,1H),7.58(dd,J=18.4,8.4Hz,2 H),7.50–7.42(m,1H),7.22(t,J=7.4Hz,1H),6.06(s,1H),4.48(t,J=6.8Hz,2H),2.62(t,J=6.8Hz,2H),2.21(s,6H).

[0210] Synthesis of compound 4:

[0211] Compound 3 (10 mmol, 3.76 g) was dissolved in 30 mL of acetone. Then, 0.5 mL of iodomethane was slowly added to the solution, and the mixture was refluxed for 3 h, forming a yellow precipitate. The precipitate was filtered to obtain the pure product. Yield: 94%.

[0212] 1 H NMR(400MHz,)δ8.59(d,J=1.5Hz,1H),8.23(d,J=7.8Hz,1H),7.95(dd,J=8.6,1.6Hz,1H),7.58(dd,J=18.4,8.4Hz,2 H),7.50–7.42(m,1H),7.22(t,J=7.4Hz,1H),6.06(s,1H),4.48(t,J=6.8Hz,2H),2.62(t,J=6.8Hz,2H),2.21(s,6H).

[0213] Example 1

[0214] Step 1: Preparation of noble metal nanoparticles

[0215] In a 500 mL round-bottom flask, dissolve 0.3 mmol of silver trifluoromethanesulfonate in 100 mL of ethanol, and then stir with a magnetic rod at 800 rpm on a stirring plate. Ensure the silver salt is completely dissolved to obtain a silver salt solution.

[0216] Weigh or measure the amount of the surfactant sodium 11-thiol sulfonate, which is similar to that of silver salts or other substances. Dissolve in 10 mL of methanol to obtain the ligand solution.

[0217] Weigh 8 mmol of sodium borohydride and add it to 150 mL of ethanol. Stir magnetically (800 rpm) until dissolved. Once NaBH4 has dissolved in the ethanol, begin filtering the solution through filter paper in a funnel into an addition funnel.

[0218] The ligand solution was added to the silver salt solution, and the silver-sulfur complex was formed after 15 minutes. Then, filtered NaBH4 solution was added dropwise through a funnel. The dropping interval was adjusted so that the NaBH4 was added over approximately one hour. After all the NaBH4 had been added, the funnel was removed. The reaction was stirred for another hour. At the end of the reaction, the magnetic stir bar was removed using a magnet placed outside the flask. The flask was closed with a septum, and a needle was inserted into the septum to release the H2 gas produced after the reaction. The reaction mixture was stored in a laboratory refrigerator (4°C) overnight to allow the nanoparticles to precipitate, yielding silver nanoparticles.

[0219] Step 2: Add N,N,N-trimethyl-2-(3-(4,4,4-trifluoro-3-oxobutyryl)-9H-carbazole-9-yl)ethyl-1-ammonium (3 mmol) was dissolved in 5 mL of methanol. The pH of the solution was adjusted to 8.0 with 1 M NaOH (3 mL), resulting in a clear solution. Then, a solution of Eu(NO3)3·6H2O (1 mmol, 0.446 g) was added to the above solution, forming a pale yellow turbid solution, which was stirred at 60 °C for 12 h. After filtration, the solution was washed several times with water and ethanol, and dried under vacuum to obtain Eu(THB)3.

[0220] Step 3: Dissolve 10 mg of silver nanoparticles in 5 mL of methanol solution and add 0.05 mmol of Eu(THB)3. Immediately after adding Eu(THB)3, begin the assembly process, centrifuge at 8000 rpm for 5 minutes, pour the solution into the container, and wash with methanol until the solution shows no red light under UV light. After ultrasonic dispersion, a physically non-clonable ink is obtained from the mixed solution. Drop 10 μL of the prepared mixed solution onto a glass slide substrate and allow it to air dry to prepare PUF tags.

[0221] in, Figure 1This is the fluorescence spectrum of the physically non-clonable ink prepared in this embodiment. Under 400 nm excitation light, the rare earth complex (Eu(THB)3) emits a europium ion characteristic peak. The assembled anti-counterfeiting ink (Ag-aggregation) also emits a europium ion characteristic peak, and through the surface-enhanced fluorescence effect of noble metal nanoparticles, the ink has a higher emission intensity.

[0222] Figure 2 This is the lifetime spectrum of the physically non-clonable ink prepared in this embodiment. The fluorescence lifetimes of the rare earth complex and the anti-counterfeiting ink at 614 nm were tested; the anti-counterfeiting ink exhibited a lower fluorescence lifetime compared to the rare earth complex.

[0223] Figure 3 This is the Raman spectrum of the physically non-clonable ink prepared in this embodiment. The Raman spectra of the rare-earth complex and the dry anti-counterfeiting ink were tested using a 785nm laser. The anti-counterfeiting ink exhibited a Raman spectrum similar to that of the rare-earth complex, and the dry ink showed higher Raman intensity due to the surface-enhanced Raman effect of the noble metal nanoparticles.

[0224] Figure 4 The manufacturing and readout steps of the physically unclonable PUF in this embodiment are as follows: The material is dissolved in methanol and dropped onto a substrate, then dried to form a random pattern. Areas are selected using a microscope as PUF tags (scale bar: 20 μm), and the corresponding response signals are obtained using a confocal system, uniformly divided into signal response units of equal area. The average intensity measured for each response unit is normalized and mapped into an encoding.

[0225] Figure 5 The tags prepared for the embodiments of the present invention are read out by fluorescence mapping with PUF tags of resolutions of 2×2, 10×10 and 40×40, and the fluorescence intensity level of each pixel is encoded, resulting in binary encoding, quaternary encoding and quaternary encoding three-dimensional maps.

[0226] Example 2

[0227] Step 1: Preparation of noble metal nanoparticles

[0228] In a 500 mL round-bottom flask, dissolve 0.45 mmol of gold chloride trihydrate in 100 mL of ethanol, then stir with a magnetic rod at 800 rpm on a stirring plate. Ensure the gold salt is completely dissolved to obtain a gold salt solution.

[0229] Weigh or measure the amount of surfactant 11-mercaptoundecanoic acid, which is similar to that of silver salts or other substances. Dissolve in 10 mL of methanol to obtain the ligand solution.

[0230] Weigh 12 mmol of sodium borohydride and add it to 200 mL of ethanol. Stir magnetically (800 rpm) until dissolved. Once NaBH4 has dissolved in the ethanol, begin filtering the solution through filter paper in a funnel into an addition funnel.

[0231] The ligand solution was added to the gold salt solution, and the gold-sulfur complex was formed after 15 minutes. Then, filtered NaBH4 solution was added dropwise through a funnel. The dropwise interval was adjusted so that the NaBH4 addition time was approximately 1.5 hours. After all NaBH4 had been added, the funnel was removed. The reaction was stirred for another hour. At the end of the reaction, the magnetic stir bar was removed using a magnet placed outside the flask. The flask was closed with a septum, and a needle was inserted into the septum to release the H2 gas generated after the reaction. The reaction mixture was stored in a laboratory refrigerator (4°C) overnight to allow the nanoparticles to precipitate, yielding gold nanoparticles.

[0232] Step 2: Add N,N,N-trimethyl-3-(4-(3-oxo-3-phenylpropionyl)phenoxy)propaneammonium (HTPP) (3 mmol) was dissolved in 7 mL of methanol. The pH of the solution was adjusted to 8.0 with 1 M NaOH (3 mL), resulting in a clear solution. Then, 0.12 mmol of Eu(NO3)3·6H2O solution was added to the above solution, forming a pale yellow turbid solution, which was stirred at 60 °C for 10 h. After filtration, the solution was washed several times with water and ethanol, and dried under vacuum to obtain Eu(TPP)3.

[0233] Step 3: Dissolve 8 mg of gold nanoparticles in 6 mL of methanol solution and add 0.05 mmol Eu(TPP)3. Immediately after adding Eu(TPP)3, begin the assembly process, centrifuge at 8000 rpm for 5 minutes, pour the solution into the container, and wash with methanol until the solution shows no red light under ultraviolet light. After ultrasonic dispersion, drop 10 μL of the mixture onto a glass slide substrate and allow it to air dry to prepare the PUF tag.

[0234] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An optical material for use in anti-counterfeiting labels, comprising noble metal nanoparticles having a first ligand and a rare earth complex, wherein the noble metal nanoparticles are linked to the rare earth complex via the first ligand, or the optical material comprises a reaction product of the noble metal nanoparticles, the rare earth complex, and the first ligand. in, The first ligand is selected from one or more of the following: sodium 9-mercaptononanesulfonate, sodium 10-mercaptodecanesulfonate, sodium 11-mercaptoundecanesulfonate, sodium 12-mercaptododecanesulfonate, sodium 13-mercaptotridecanesulfonate, 9-mercaptononaneic acid, 10-mercaptodecaneic acid, 11-mercaptoundecaneic acid, 12-mercaptododecaneic acid, and 13-mercaptotridecaneic acid. The rare earth complex is selected from complexes formed by rare earth metal salts and second ligands, wherein the rare earth metal salt is selected from europium salts and / or terbium salts, and the second ligand is selected from: or ; The precious metal nanoparticles are selected from gold nanoparticles or silver nanoparticles. The method for preparing the optical material that can be used in anti-counterfeiting labels includes: S1: A first solution containing a noble metal salt is reacted with a second solution containing a first ligand to obtain a first reaction product having the first ligand; the solvent of the first solution is selected from a C1-C6 monohydric alcohol; the solvent of the second solution is selected from a C1-C6 monohydric alcohol. S2: The first reaction product having the first ligand is reacted with a third solution including a reducing agent to obtain noble metal nanoparticles having the first ligand; the solvent of the third solution is selected from a C1-C6 monohydric alcohol; the reducing agent is selected from sodium borohydride or borane-tert-butylamine. S3: The noble metal nanoparticles with the first ligand are mixed with the rare earth complex in methanol solvent.

2. The optical material according to claim 1, characterized in that, The particle size of the noble metal nanoparticles is 5nm-200nm.

3. The optical material according to claim 1, characterized in that, The particle size of the noble metal nanoparticles is 10nm-50nm.

4. The optical material according to any one of claims 1-3, characterized in that, In step S1, the noble metal salt is selected from one or more of gold chloride trihydrate, silver trifluoromethanesulfonate, silver nitrate, and hexachloroplatinic acid; and / or In step S3, the preparation of the rare earth complex includes: reacting a fourth solution containing the second ligand with a rare earth metal salt to obtain a reaction product, and then performing solid-liquid separation on the reaction product to obtain the rare earth complex.

5. The optical material according to any one of claims 1-3, characterized in that, In step S1, the solvent of the first solution is selected from one or more of methanol, ethanol, and isopropanol; and / or the solvent of the second solution is selected from one or more of methanol, ethanol, and isopropanol; and / or In step S2, the solvent of the third solution is selected from one or more of methanol, ethanol and isopropanol.

6. The optical material according to claim 4, characterized in that, In step S3, the solvent of the fourth solution is selected from monohydric alcohols of C1-C6.

7. The optical material according to claim 6, characterized in that, The solvent of the fourth solution is selected from one or more of methanol, ethanol and isopropanol.

8. The optical material according to any one of claims 1-3, characterized in that, In step S1, the molar ratio of the noble metal salt to the first ligand, calculated as a noble metal, is 1:0.5 to 1:5, and / or the reaction time is 5 min to 90 min, and / or the reaction temperature is 5℃ to 30℃; and / or In step S2, the molar ratio of the noble metal salt to the reducing agent is 1:3 to 1:50 (based on precious metal); and / or the second reaction time is 0.5 h to 5 h; and / or the second reaction temperature is 5 °C to 30 °C; and / or In step S3, the molar ratio of the noble metal nanoparticles to the rare earth complex is 1 mg:(0.001-0.01) mmol; and / or the ratio of the noble metal nanoparticles to the solvent volume is (1-5) mg:1 mL; the ratio of the rare earth complex to the solvent volume is (1-5) mg:1 mL.

9. The optical material according to claim 4, characterized in that, The molar ratio of the rare earth metal salt to the second ligand is 1:0.1 to 1:3, and / or the time of the fourth reaction is 3h-24h, and / or the temperature of the fourth reaction is 30℃-70℃.

10. The optical material according to any one of claims 1-3, characterized in that, In step S1, the molar ratio of the noble metal salt to the first ligand, calculated as a noble metal, is 1:1 to 1:3, and / or the time of the first reaction is 15 min to 60 min, and / or In step S2, the molar ratio of the noble metal salt to the reducing agent is 1:10 to 1:30 (based on precious metal); and / or the second reaction time is 1-3 hours; and / or In step S3, the molar ratio of the noble metal nanoparticles to the rare earth complex is 1 mg:(0.003-0.008) mmol; and / or the ratio of the noble metal nanoparticles to the solvent volume is (2-3) mg:1 mL; the ratio of the rare earth complex to the solvent volume is (2-3) mg:1 mL.

11. An anti-counterfeiting ink comprising the optical material and solvent as described in any one of claims 1-10.

12. The anti-counterfeiting ink according to claim 11, characterized in that, The solvent is selected from water and C1-C6 monohydric alcohols.

13. The anti-counterfeiting ink according to claim 12, characterized in that, The solvent is selected from methanol and / or ethanol.

14. A method for preparing anti-counterfeiting ink according to any one of claims 11-13, comprising: S1: A first solution containing a noble metal salt is reacted with a second solution containing a first ligand to obtain a first reaction product containing the first ligand; S2: The first reaction product containing the first ligand is reacted with a third solution including a reducing agent to obtain noble metal nanoparticles containing the first ligand. S3: Mix the noble metal nanoparticles with the first ligand and the rare earth complex in a solvent.

15. The preparation method according to claim 14, characterized in that, In step S1, the solvent of the first solution is selected from C1-C6 monohydric alcohols; and / or the noble metal salt is selected from one or more of gold chloride trihydrate, silver trifluoromethanesulfonate, silver nitrate, and hexachloroplatinic acid; and / or the solvent of the second solution is selected from C1-C6 monohydric alcohols; and / or In step S2, the solvent of the third solution is selected from C1-C6 monohydric alcohols; and / or the reducing agent is selected from sodium borohydride or borane-tert-butylamine; and / or In step S3, the preparation of the rare earth complex includes: reacting a fourth solution containing the second ligand with a rare earth metal salt to obtain a reaction product, and then performing solid-liquid separation on the reaction product to obtain the rare earth complex.

16. The preparation method according to claim 15, characterized in that, In step S1, the solvent of the first solution is selected from one or more of methanol, ethanol, and isopropanol; and / or the solvent of the second solution is selected from one or more of methanol, ethanol, and isopropanol; and / or In step S2, the solvent of the third solution is selected from one or more of methanol, ethanol, and isopropanol; and / or In step S3, the solvent of the fourth solution is selected from monohydric alcohols of C1-C6.

17. The preparation method according to claim 16, characterized in that, The solvent of the fourth solution is selected from one or more of methanol, ethanol and isopropanol.

18. The preparation method according to claim 15, characterized in that, In step S1, the molar ratio of the noble metal salt to the first ligand, calculated as a noble metal, is 1:0.5 to 1:5, and / or the reaction time is 5 min to 90 min, and / or the reaction temperature is 5℃ to 30℃; and / or In step S2, the molar ratio of the noble metal salt to the reducing agent is 1:3 to 1:50 (based on precious metal); and / or the second reaction time is 0.5 h to 5 h; and / or the second reaction temperature is 5 °C to 30 °C; and / or In step S3, the molar ratio of the noble metal nanoparticles to the rare earth complex is 1 mg:(0.001-0.01) mmol; and / or the ratio of the noble metal nanoparticles to the solvent volume is (1-5) mg:1 mL; the ratio of the rare earth complex to the solvent volume is (1-5) mg:1 mL; and / or The molar ratio of the rare earth metal salt to the second ligand is 1:0.1 to 1:3, and / or the time of the fourth reaction is 3h-24h, and / or the temperature of the fourth reaction is 30℃-70℃.

19. The preparation method according to claim 18, characterized in that, In step S1, the molar ratio of the noble metal salt to the first ligand, calculated as a noble metal, is 1:1 to 1:3, and / or the time of the first reaction is 15 min to 60 min, and / or In step S2, the molar ratio of the noble metal salt to the reducing agent is 1:10 to 1:30 (based on precious metal); and / or the second reaction time is 1-3 hours; and / or In step S3, the molar ratio of the noble metal nanoparticles to the rare earth complex is 1 mg:(0.003-0.008) mmol; and / or the ratio of the noble metal nanoparticles to the solvent volume is (2-3) mg:1 mL; the ratio of the rare earth complex to the solvent volume is (2-3) mg:1 mL.

20. A non-cloning anti-counterfeiting label, comprising a substrate layer, a protective layer, and an anti-counterfeiting layer located between the substrate layer and the protective layer, wherein, The anti-counterfeiting layer is formed from the optical material described in any one of claims 1-10, or from the anti-counterfeiting ink prepared by any one of claims 11-13 or the preparation method described in any one of claims 14-19.

21. The non-cloning anti-counterfeiting label according to claim 20, characterized in that, The method for preparing the non-cloneable anti-counterfeiting label includes dropping the anti-counterfeiting ink onto the substrate layer, allowing the anti-counterfeiting ink to evaporate and dry to obtain an anti-counterfeiting layer, and then covering the anti-counterfeiting layer with the protective layer.

22. The non-cloning anti-counterfeiting label according to claim 20 or 21, characterized in that, The substrate layer is selected from glass and / or plastic; the area of ​​the substrate layer is 1 mm². 2 -25mm 2 .

23. The non-cloning anti-counterfeiting label according to claim 20 or 21, characterized in that, The area of ​​the substrate layer is 4 mm. 2 -9mm 2 .

24. A method for identifying anti-counterfeiting labels, comprising placing an unclonable anti-counterfeiting label as described in any one of claims 20-23 in a confocal system to obtain an intensity mapping image, acquiring data from the image and performing digital processing to form anti-counterfeiting coding information, wherein the confocal system includes confocal fluorescence, confocal lifetime, and confocal Raman.

25. The method for identifying anti-counterfeiting labels according to claim 24, characterized in that, The data is pixel location information, and the pixel information includes fluorescence intensity, fluorescence wavelength, fluorescence lifetime, Raman wavelength, and Raman intensity at the same location on the substrate.

26. The method for identifying anti-counterfeiting labels according to claim 24, characterized in that, When using a confocal system to analyze information on anti-counterfeiting labels, intensity information is obtained from peaks in fluorescence spectroscopy, Raman spectroscopy, and lifetime spectroscopy. When using two or more detection methods, different information contained in the same orthogonal pixel is selected.

27. The method for identifying anti-counterfeiting labels according to claim 24, characterized in that, The digitization process includes data preprocessing and digitization of the data obtained from the image.

28. The method for identifying anti-counterfeiting labels according to claim 27, characterized in that, The data preprocessing involves filtering out some noise from the Raman signal information and removing background signals. and / or The digitization process involves normalizing and segmenting the fluorescence intensity, Raman intensity, and fluorescence lifetime using testing software to form relative signal intensities; combining the position information of each pixel with the signal intensity information to form anti-counterfeiting coding information.

29. The method for identifying anti-counterfeiting labels according to claim 28, characterized in that, The digitization includes the following steps: a. Normalize the intensity values ​​of each fluorescence intensity, Raman signal, and lifetime signal, and quantize the signal intensity value of each pixel; b. Combining the position information of each pixel, the different signal intensities after segmentation are used to form anti-counterfeiting coding information; c. Conduct repeatability tests to obtain more accurate labeling results. Compare the data obtained from the repeat tests to verify the reliability of the label tests. If the tests pass, input the data into the database; and / or The anti-counterfeiting label identification method also includes verification, which involves using other confocal devices to collect anti-counterfeiting pattern information and comparing it with data in the database. If a single confocal device is used for collection, the information is compared with the corresponding database information. If two or more confocal devices are used for collection, the information is compared with relevant or all database information.

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