阅读说明：本技术 氧化石墨烯诱导的Eu3+复合物及其制备方法和应用 (Graphene oxide induced Eu3+Composite and preparation method and application thereof ) 是由 朱保华 师睿 范建明 王哲旭 潘澄 于 2021-01-21 设计创作，主要内容包括：本发明公开了氧化石墨烯诱导的Eu～(3+)复合物及其制备方法和应用,氧化石墨烯诱导的Eu～(3+)复合物在扫描电子显微镜下,其形貌呈现出多层的六瓣花形形貌；其制备方法包括：(1)制备H-6CPB和Eu(NO-3)-3·6H-2O的DMF分散液；(2)制备氧化石墨烯诱导混合溶液；(3)制备得到氧化石墨烯诱导的Eu～(3+)复合物；其可用于制备荧光防伪印油、荧光防伪油漆或荧光防伪油墨。本发明氧化石墨烯诱导的Eu～(3+)复合物具有花瓣形的微观结构,只有在显微镜下才能观察到独特六瓣多层的立体微观形貌,且在荧光显微镜下还可观察到发出红色荧光的微观形貌,使防伪变得高级不易伪造。(The invention discloses a graphene oxide induced Eu 3+ Composite, preparation method and application thereof, and Eu induced by graphene oxide 3+ The appearance of the compound presents a multi-layer hexapetalous flower shape under a scanning electron microscope; the preparation method comprises the following steps: (1) preparation H 6 CPB and Eu (NO) 3 ) 3 ·6H 2 DMF dispersion of O; (2) preparing a graphene oxide induction mixed solution; (3) preparing to obtain the Eu induced by the graphene oxide 3+ A complex; it can be used for preparing fluorescent anti-counterfeiting stamp-pad ink, fluorescent anti-counterfeiting paint or fluorescent anti-counterfeiting ink. Eu induced by graphene oxide 3+ The compound has a petal-shaped microstructure, the unique three-dimensional microstructure of six-petal multilayer can be observed only under a microscope, and the compound can also be observed under a fluorescence microscopeThe microscopic appearance of the red fluorescence is observed, so that the anti-counterfeiting becomes high-grade and is not easy to forge.)

1. Graphene oxide induced Eu³⁺The compound is characterized by having an infrared absorption peak of 2980cm^-1，2850cm^-1，1612cm^-1，1403cm^-1，1087cm^-1(ii) a Under a scanning electron microscope, the appearance of the material presents a multi-layer hexapetalous flower shape; under the excitation of 275nm wavelength, emission peaks at 579nm, 591nm, 614nm, 652nm and 702nm respectively correspond to Eu³⁺Is/are as follows⁵D₀→⁷F₀、⁵D₀→⁷F₁、⁵D₀→⁷F₂、⁵D₀→⁷F₃And⁵D₀→⁷F₄wherein, the transition of⁵D₀→⁷F₂The strongest emission band.

2. Graphene oxide-induced Eu according to claim 1³⁺A method for preparing a composite, comprising the steps of: (1) preparation H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O; (2) preparing a graphene oxide induction mixed solution; (3) preparing to obtain the Eu induced by the graphene oxide³⁺A complex; wherein the content of the first and second substances,

(1) preparation H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O: taking H in proportion₆CPB and Eu (NO)₃)₃·6H₂Mixing O, adding into the mixed solution of water and DMF, adding acid to control pH value, heating and stirring, and ultrasonically dispersing the mixture uniformly to obtain H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O;

(2) preparing a graphene oxide induction mixed solution: subjecting said H to₆CPB and Eu (NO)₃)₃·6H₂Adding the DMF dispersion liquid of O into the single-layer graphene oxide aqueous dispersion liquid, and uniformly mixing by ultrasonic waves to prepare a graphene oxide induced mixed solution;

(3) preparing to obtain the Eu induced by the graphene oxide³⁺The compound is as follows: transferring the graphene oxide induced mixed solution into a high-pressure reaction kettle for solvothermal reaction, washing, filtering and drying a product after the reaction to obtain a gray powdery product, namely the Eu induced by the graphene oxide³⁺And (c) a complex.

3. Graphene oxide induced Eu according to claim 2³⁺The preparation method of the compound is characterized in that in the step (1), H₆CPB with Eu (NO)₃)₃·6H₂The molar ratio of O is 0.5:1-1: 1; the volume ratio of water to DMF is 3:5-5: 5; adding 0.15-0.2mmol of H into 8-10mL of mixed solution of water and DMF₆CPB and Eu (NO)₃)₃·6H₂And (3) a mixed solution of O.

4. Graphene oxide induced Eu according to claim 2³⁺The preparation method of the compound is characterized in that in the step (1), the added acid is concentrated nitric acid, and the pH value is controlled to be 5.5-6.5; the heating temperature is 50-60 ℃.

5. Graphene oxide induced Eu according to claim 2³⁺The preparation method of the composite is characterized in that in the step (2), the volume ratio of the mixed solution of water and DMF to the single-layer graphene oxide aqueous dispersion is 4:1-20: 1; wherein the concentration of the single-layer graphene oxide aqueous dispersion is 1 g/mL.

6. Graphene oxide induced Eu according to claim 2³⁺The preparation method of the compound is characterized in that in the step (3), the solvothermal reaction conditions are as follows: keeping the temperature at 60-80 ℃ for 24-72 hours, and then cooling to room temperature at the cooling rate of 0.3-0.8 ℃ per hour to complete the induction reaction.

7. Graphene oxide-induced Eu according to claim 1³⁺The compound is used for preparing fluorescent materials.

8. Graphene oxide-induced Eu according to claim 7³⁺The fluorescent material used for preparing the compound is any one of fluorescent anti-counterfeiting stamp-pad ink, fluorescent anti-counterfeiting paint or fluorescent anti-counterfeiting ink.

The technical field is as follows:

the invention relates to Eu³⁺A compound and a preparation method and anti-counterfeiting application thereof, in particular to Eu induced by graphene oxide³⁺A compound, a preparation method and anti-counterfeiting application thereof.

Background art:

the fluorescent anti-counterfeiting label is an effective means for identifying the authenticity of the commodity due to the characteristics of easy manufacture, difficult copying, easy characterization or detection and the like.

In recent years, trivalent rare earth complexes coordinated with conjugated organic ligands have attracted attention because of their characteristics of high luminous intensity, high fluorescence efficiency, long luminous life, good thermal stability, and the like. Therefore, these complexes have important applications in fluorescence immunoassay, pharmaceutical analysis, electroluminescent devices, anti-counterfeit labels and agricultural films.

The invention content is as follows:

the first purpose of the invention is to provide the graphene oxide-induced Eu, wherein the unique six-lobe multilayer three-dimensional micro-morphology can be observed only under a microscope, and the micro-morphology emitting red fluorescence can be observed under a fluorescence microscope³⁺And (c) a complex.

The second purpose of the invention is to provide the graphene oxide-induced Eu which has the advantages of simple synthesis, stable structure, good repeatability and obvious photoluminescence effect³⁺A method for preparing the compound.

The third purpose of the invention is to provide the Eu induced by the graphene oxide³⁺Use of a complex.

The first purpose of the invention is implemented by the following technical scheme: graphene oxide induced Eu³⁺The compound is characterized by having an infrared absorption peak of 2980cm^-1，2850cm^-1，1612cm^-1，1403cm^-1，1087cm^-1(ii) a Under a scanning electron microscope, the appearance of the material presents a multi-layer hexapetalous flower shape; under the excitation of 275nm wavelength, emission peaks at 579nm, 591nm, 614nm, 652nm and 702nm respectively correspond to Eu³⁺Is/are as follows⁵D₀→⁷F₀、⁵D₀→⁷F₁、⁵D₀→⁷F₂、⁵D₀→⁷F₃And⁵D₀→⁷F₄wherein, the transition of⁵D₀→⁷F₂The strongest emission band.

The second purpose of the invention is implemented by the following technical scheme: graphene oxide induced Eu³⁺A method of preparing a composite comprising the steps of: (1) preparation H₆CPB (1,1':2',1 '-tris-4, 4' -dicarboxylic acid) and Eu (NO)₃)₃·6H₂DMF (dimethylformamide) dispersion of O (hydrated rare earth europium nitrate); (2) preparing a graphene oxide induction mixed solution; (3) preparing to obtain the Eu induced by the graphene oxide³⁺A complex; wherein the content of the first and second substances,

(1) preparation H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O: taking H in proportion₆CPB and Eu (NO)₃)₃·6H₂Mixing O, adding into the mixed solution of water and DMF, adding acid to control pH value, heating and stirring, and ultrasonically dispersing the mixture uniformly to obtain H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O;

(2) preparing a graphene oxide induction mixed solution: subjecting said H to₆CPB and Eu (NO)₃)₃·6H₂Adding the DMF dispersion liquid of O into the single-layer graphene oxide aqueous dispersion liquid, and uniformly mixing by ultrasonic waves to prepare a graphene oxide induced mixed solution;

(3) preparing to obtain the Eu induced by the graphene oxide³⁺The compound is as follows: transferring the graphene oxide induced mixed solution into a high-pressure reaction kettle for solvothermal reaction, washing, filtering and drying a product after the reaction to obtain a gray powdery product, namely the Eu induced by the graphene oxide³⁺And (c) a complex. The high-pressure reaction kettle is a stainless steel reaction kettle lined with polytetrafluoroethylene; by utilizing oxygen-containing functional groups on the surface of graphene oxide, the graphene oxide and the complex are successfully compounded through coordination bonds, hydrogen bonds and electrostatic interaction, and under the induction of a graphene oxide matrix, the complex grows into a multilayer six-petal flower shapeAnd (5) appearance.

Further, in the step (1), H₆CPB with Eu (NO)₃)₃·6H₂The molar ratio of O is 0.5:1-1: 1; the volume ratio of water to DMF is 3:5-5: 5; adding 0.15-0.2mmol of H into 8-10mL of mixed solution of water and DMF₆CPB and Eu (NO)₃)₃·6H₂And (3) a mixed solution of O.

Further, in the step (1), the added acid is concentrated nitric acid, and the pH value is controlled to be 5.5-6.5; the heating temperature is 50-60 ℃.

Further, in the step (2), the volume ratio of the mixed solution of water and DMF to the single-layer graphene oxide aqueous dispersion is 4:1-20: 1; wherein the concentration of the single-layer graphene oxide aqueous dispersion is 1 g/mL.

Further, in the step (3), the conditions of the solvothermal reaction are as follows: keeping the temperature at 60-80 ℃ for 24-72 hours, and then cooling to room temperature at the cooling rate of 0.3-0.8 ℃ per hour to complete the induction reaction. The solvent thermal reaction is that in a stainless steel reaction kettle lined with polytetrafluoroethylene, water and DMF are used as reaction media, and a temperature-controlled oven is used for heating, so that autogenous pressure is generated inside a container, and substances which are difficult to dissolve or insoluble are dissolved and separated out under normal conditions.

The third object of the invention is implemented by the following technical scheme: graphene oxide induced Eu³⁺The compound is used for preparing fluorescent materials.

Further, the fluorescent material is any one of fluorescent anti-counterfeiting stamp-pad ink, fluorescent anti-counterfeiting paint or fluorescent anti-counterfeiting ink.

The invention has the advantages that:

1. eu induced by graphene oxide³⁺The compound is a high-grade fluorescent material which can stably exist under a common state (one atmosphere pressure and room temperature), has the advantages of simple synthesis, stable structure, good repeatability, obvious photoluminescence effect and the like, can be used as a photoluminescence material, can be used as a main active component of fluorescent anti-counterfeiting stamp-pad ink, fluorescent anti-counterfeiting paint or fluorescent anti-counterfeiting ink, and is expected to be applied to the technical field of fluorescent chemical materials.

2. Hair brushBright graphene oxide induced Eu³⁺The compound has a petal-shaped microstructure, the unique six-petal multilayer three-dimensional microstructure can be observed only under a microscope, and the microstructure emitting red fluorescence can be observed under a fluorescence microscope, so that the anti-counterfeiting effect is advanced and is not easy to counterfeit.

3. Eu induced by graphene oxide of the invention³⁺Compared with commercial common stamp-pad ink, the fluorescent anti-counterfeiting stamp-pad ink prepared from the compound can show red fluorescence under an ultraviolet lamp besides the visible appearance color on a stamping trace, so that the fluorescent anti-counterfeiting stamp-pad ink can be applied to the technical field of red fluorescent anti-counterfeiting stamp-pad ink.

Description of the drawings:

FIG. 1 shows the Eu induced by graphene oxide prepared in example 2³⁺An infrared spectrum of the complex;

FIG. 2 shows the Eu induced by graphene oxide prepared in example 2³⁺XRD spectrum of the compound;

FIG. 3 shows the Eu induced by graphene oxide prepared in example 2³⁺Scanning electron microscopy of the composite;

FIG. 4 shows the Eu induced by graphene oxide prepared in example 2³⁺A fluorescence spectrum of the complex;

FIG. 5 shows the Eu induced by graphene oxide prepared in example 2³⁺The effect graph of the specific application example of the compound observed under natural light;

FIG. 6 shows the Eu induced by graphene oxide prepared in example 2³⁺The effect graph of the specific application example of the compound is observed under 256nm ultraviolet light;

FIG. 7 shows the Eu induced by graphene oxide prepared in example 2³⁺The specific application example of the compound is observed under a fluorescence microscope;

FIG. 8 shows the Eu induced by graphene oxide prepared in example 2³⁺The composite specific application example was observed under a bright field microscope.

FIG. 9 shows the Eu induced by graphene oxide prepared in example 2³⁺The compound is respectively kept at 25 deg.C, 100 deg.C and 200 deg.C for 30min, and observed under 256nm ultraviolet light;

FIG. 10 shows the Eu induced by graphene oxide prepared by repeating the experiment in exactly the same manner as in example 2³⁺Scanning electron microscopy of the composite.

The specific implementation mode is as follows:

in order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

For the purposes of simplicity and clarity, descriptions of well-known technologies are omitted appropriately below so as not to obscure the description of the present technical solution with unnecessary details. Starting materials H for the preparation of the Compounds of the invention₆CPB (1':2',1 "-tris-4, 4" -dicarboxylic acid) was synthesized by published literature (Nguyen P T, Nguyen H T, Pham H Q, et al₂Capture Properties of a Series of Hexatopic Linker-Based Metal-Organic frameworks Inorganic Chemistry 2015,54: 10065). Graphene oxide and the hydrated rare earth europium nitrate are commercially available. Graphene oxide monolayers are prepared by a modified hummers method, see in particular literature Xiaoxiong Zhang, Wenjun Zhang, Yingjie Li, Cuiluo Li, Hybrid luminescence materials of graphene oxide and raw-earth complexes with strain luminescence center and beta thermal stability. dyes piezo, 2017,140, 150. ang. 156.

Example 1: graphene oxide induced Eu³⁺The compound is characterized by having an infrared absorption peak of 2980cm^-1，2850cm^-1，1625cm^-1，1403cm^-1，1186cm^-1(ii) a Under a scanning electron microscope, the appearance of the material presents a multi-layer hexapetalous flower shape; under the excitation of 275nm wavelength, emission peaks at 579nm, 591nm, 614nm, 652nm and 702nm are respectivelyCorresponding to Eu³⁺Is/are as follows⁵D₀→⁷F₀、⁵D₀→⁷F₁、⁵D₀→⁷F₂、⁵D₀→⁷F₃And⁵D₀→⁷F₄wherein, the transition of⁵D₀→⁷F₂The strongest emission band.

Example 2: graphene oxide-induced Eu in example 1³⁺The compound can be prepared by the following method: 0.1mmol of H is taken₆CPB (1,1':2',1 '-tris-4, 4' -dicarboxylic acid) and 0.1mmol Eu (NO)₃)₃·6H₂Mixing O (hydrated rare earth europium nitrate), adding the mixture into a mixed solution of 3mL of water and 5mL of DMF (dimethyl formamide), dropwise adding concentrated nitric acid, and controlling the pH value to be 6; then heating and stirring at the temperature of 60 ℃, and then ultrasonically dispersing the mixture uniformly to prepare H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O;

then, the prepared H₆CPB and Eu (NO)₃)₃·6H₂And adding the DMF dispersion liquid of O into 1mL of 1g/mL monolayer graphene oxide aqueous dispersion liquid, and uniformly mixing by ultrasonic treatment for 0.5 hour to prepare the graphene oxide induced mixed solution.

And transferring the prepared graphene oxide induction mixed solution into a 25mL high-pressure reaction kettle, keeping the temperature at 70 ℃ for 48 hours, and then cooling to room temperature at the cooling rate of 0.5 ℃ per hour to complete the induction reaction. Washing the product with absolute ethyl alcohol for multiple times, performing ultrasonic treatment in the absolute ethyl alcohol for 2 hours, filtering and drying to obtain a gray powder product, namely, Eu induced by graphene oxide³⁺And (c) a complex.

The grey powder product prepared in this example was characterized as follows:

(1) infrared spectrum determination:

the infrared spectrum is measured on an infrared spectrometer of Thermo Nicolet Avatar 370 by adopting a potassium sniffing tabletting method, and the scanning range is 500-4000cm^-1. As shown in FIG. 1, the gray powder product has a characteristic infrared absorption peak of 2980cm^-1，2850cm^-1，1612cm^-1，1403 cm^-1，1087cm^-1。

(2) Phase analysis

Phase analysis was determined on an X-ray powder diffractometer from Panalytical Empyre by thoroughly grinding the sample using an agate mortar. As shown in fig. 2, a diffraction peak having a maximum base surface distance d of 0.814nm and a large peak width appears at 2 θ of 10.587 °, which is a characteristic diffraction peak of graphene oxide. H₆CPB-Eu-GO (1,1':2',1 '-tris-4, 4' -dicarboxylic acid-europium-graphene oxide) vs. H₆The XRD data of CPB-Eu (1,1':2',1 '-tris-4, 4' -dicarboxylic acid-europium) is slightly shifted to the left, which is probably due to the introduction of graphene oxide, which causes the lattice constant of the composite to become large, and thus causes a left shift. At H₆A characteristic diffraction peak of GO (graphene oxide) appears in CPB-Eu-GO, which shows that the graphene oxide is successfully compounded.

(3) Characterization of microscopic features

The micro-morphology is observed on a Hitachi S-4800 scanning electron microscope by uniformly dispersing a sample in ethanol, dripping the ethanol on a silicon wafer, and compounding Eu on graphene oxide as shown in figure 3³⁺Complex (H)₆CPB-Eu) is flower-shaped, six petals, multi-layer, and is similar to a rose. Due to oxygen-containing functional groups on the surface of the graphene oxide, the graphene oxide and the complex are successfully compounded through coordination bonds, hydrogen bonds and electrostatic action, and under the induction of a graphene oxide matrix, the complex grows into a multilayer hexapetalous flower-shaped appearance.

(4) Optical Performance testing

The sample was further ground and tested for solid state fluorescence using an FLS920 fluorescence spectrometer, the results of which are shown in fig. 4. The test results show that H₆CPB-Eu and H₆The excitation wavelength of the CPB-Eu-GO is 275 nm. Emission peaks at 579nm, 591nm, 614nm, 652nm and 702nm respectively correspond to Eu³⁺Is/are as follows⁵D₀→⁷F₀、⁵D₀→⁷F₁、⁵D₀→⁷F₂、⁵D₀→⁷F₃And⁵D₀→⁷F₄wherein, the transition of⁵D₀→⁷F₂The strongest emission band.

(5) Stability test

Graphene oxide-induced Eu prepared in example 2³⁺The complex is respectively kept at 25 ℃, 100 ℃ and 200 ℃ for 30min, and after being cooled to room temperature, the complex still has the characteristic red light of the europium complex when being observed under 365nm ultraviolet light, and as shown in figure 9, the structure of the complex is stable.

(6) Repeatability test

A repetitive experiment was carried out by the method of example 2 to prepare the obtained graphene oxide-induced Eu³⁺The compound still has obvious multilayer hexapetalous flower-shaped morphology by observing the morphology of the compound by using a scanning electron microscope, as shown in fig. 10.

Example 3: graphene oxide-induced Eu in example 1³⁺The compound can be prepared by the following method: 0.05mmol of H is taken₆CPB (1,1':2',1 '-tris-4, 4' -dicarboxylic acid) and 0.1mmol Eu (NO)₃)₃·6H₂Mixing O (hydrated rare earth europium nitrate), adding the mixture into a mixed solution of 5mL of water and 5mL of DMF (dimethyl formamide), dropwise adding concentrated nitric acid, and controlling the pH value to be 6.5; then heating and stirring at the temperature of 50 ℃, and then ultrasonically dispersing the mixture uniformly to prepare H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O;

then, the prepared H₆CPB and Eu (NO)₃)₃·6H₂And adding the DMF dispersion liquid of O into 1mL of 1g/mL monolayer graphene oxide aqueous dispersion liquid, and uniformly mixing by ultrasonic treatment for 0.5 hour to prepare the graphene oxide induced mixed solution.

And transferring the prepared graphene oxide induction mixed solution into a 25mL high-pressure reaction kettle, keeping the temperature at 80 ℃ for 24 hours, and then cooling to room temperature at the cooling rate of 0.3 ℃ per hour to complete the induction reaction. Washing the product with anhydrous ethanol for several times, performing ultrasonic treatment in anhydrous ethanol for 2 hr, filtering, and drying to obtain gray powderThe product is graphene oxide-induced Eu³⁺And (c) a complex.

The graphene oxide-induced Eu prepared in the embodiment³⁺The compound is observed by a scanning electron microscope, and has obvious multilayer hexapetalous flower-shaped appearance.

Example 4: graphene oxide-induced Eu in example 1³⁺The compound can be prepared by the following method: 0.08mmol of H₆CPB (1,1':2',1 '-tris-4, 4' -dicarboxylic acid) and 0.1mmol Eu (NO)₃)₃·6H₂Mixing O (hydrated rare earth europium nitrate), adding the mixture into a mixed solution of 4mL of water and 5mL of DMF (dimethyl formamide), dropwise adding concentrated nitric acid, and controlling the pH value to be 5.5; then heating and stirring the mixture at the temperature of 55 ℃, and then ultrasonically dispersing the mixture uniformly to prepare H₆CPB and Eu (NO)₃)₃·6H₂DMF dispersion of O;

then, the prepared H₆CPB and Eu (NO)₃)₃·6H₂And adding the DMF dispersion liquid of O into 0.5mL of 1g/mL monolayer graphene oxide aqueous dispersion liquid, and uniformly mixing by ultrasonic treatment for 0.5 hour to prepare the graphene oxide induced mixed solution.

And transferring the prepared graphene oxide induction mixed solution into a 25mL high-pressure reaction kettle, keeping the temperature at 60 ℃ for 72 hours, and then cooling to room temperature at the cooling rate of 0.8 ℃ per hour to complete the induction reaction. Washing the product with absolute ethyl alcohol for multiple times, performing ultrasonic treatment in the absolute ethyl alcohol for 2 hours, filtering and drying to obtain a gray powder product, namely, Eu induced by graphene oxide³⁺And (c) a complex.

The graphene oxide-induced Eu prepared in the embodiment³⁺The compound is observed by a scanning electron microscope, and has obvious multilayer hexapetalous flower-shaped appearance.

Example 5: example 2 preparation of resultant graphene oxide-induced Eu³⁺Examples of applications of the composite. Graphene oxide-induced Eu prepared in example 2³⁺The composite sample was mixed with aloe vera gel to prepare an ink, and the ink was used to print a badge pattern of university of inner Mongolia as shown in FIG. 5 under natural lightThe pattern was observed as a white blot. As shown in FIG. 6, under 256nm ultraviolet light, the pattern emits bright red fluorescence, which can be used for macroscopic fluorescence anti-counterfeiting. As shown in FIG. 7, under a 40-fold fluorescence microscope, a multi-layered hexapetalous flower pattern can be observed, and Eu is shown³⁺The characteristic red color of the complex; FIG. 8 is a photograph of a sample under a bright field 40 times microscope, wherein a six-petal flower shape can be clearly observed; eu induced by graphene oxide³⁺The compound can realize microscopic anti-counterfeiting.

Eu induced by graphene oxide of the invention³⁺Compared with commercial common stamp-pad ink, the fluorescent anti-counterfeiting stamp-pad ink prepared from the compound can be applied to the technical field of red fluorescent anti-counterfeiting stamp-pad ink because the fluorescent anti-counterfeiting stamp-pad ink shows red fluorescence under an ultraviolet lamp besides the visible appearance color on a stamping trace. In addition, the obvious characteristic that the red microscopic morphology can be observed under a high-power fluorescence microscope provides possibility for realizing high-grade anti-counterfeiting, so that the anti-counterfeiting becomes high-grade and is not easy to forge.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.