A multi-mode fluorescent anti-counterfeiting material and anti-counterfeiting demonstration device

Abstract

The present invention belongs to the technical field of luminescence and display, and particularly relates to a multi-mode fluorescent anti-counterfeiting material and an anti-counterfeiting demonstration device. The molecular formula of the multi-mode fluorescent anti-counterfeiting material is Re2O2S:0.08Yb,0.02Er@Re2O2S:0.05Tb (Re = Y, Gd, La). The Re2O2S:0.08Yb,0.02Er@Re2O2S:0.05Tb (Re = Y, Gd, La) anti-counterfeiting material provided by the present invention exhibits different luminescent colors at 1530 nm, 980 nm, 254 nm (or X-ray) and different temperatures. Compared with the single / double-mode materials that can produce one or two luminescent colors under excitation at one or two specific wavelengths in the past, it has a higher anti-counterfeiting level, is difficult to be replaced and forged, and greatly improves the security of anti-counterfeiting.

Description

Technical Field

[0001] The invention relates to a multi-mode fluorescent anti-counterfeiting material and an anti-counterfeiting demonstration device, belonging to the technical field of luminescence and display. Background Art

[0002] Counterfeit and shoddy products have seriously affected the normal development of social economy and people's lives, and have become an increasingly serious global problem, causing huge economic losses every year. They are regarded as "the second largest public hazard in the world after drug trafficking" internationally. In order to protect the legitimate rights and interests of consumers and enterprises, anti-counterfeiting technology research has become an international frontier hotspot in recent years, and a large number of related reports have appeared. Among them, fluorescent anti-counterfeiting technology has attracted widespread attention due to its advantages such as high concealment, easy observation, difficult to copy, and large-scale production.

[0003] The luminescent materials used in fluorescent anti-counterfeiting technology mainly include rare earth luminescent materials [(1)WU Youfusheng,WU Wei.Combinations of superior inorganic phosphors for level-tunable information hiding and encoding.Advanced Optical Materials,2021,9(17):2100281;(2)TSANG Mingkiu,BAI Gongxun,HAO Jianhua.Stimuli-responsive up conversion luminescence nanomaterials and films for various applications.Chemical Society Reviews,2015,44(6):1585-1607;(3)LIU Xiaowang,JI Qiang,HU Qiyan,et al.Dual-mode long-lived luminescence of Mn 2+-doped nanoparticles for multilevel anti-counterfeiting. ACS Applied Materials & Interface, 2019, 11(33): 30146-30153.], semiconductor quantum dots [(4) XU Leimeng, CHEN Jiawei, SONG Jizhong, et al. Double protected all-inorganic perovskite nanocrystals by crystalline matrix and silica for triple-moddal anti-counterfeiting codes. ACS Applied Materials & Interface, 2017, 9(31): 26556-26564; (5) CHEN Xi, WANG Qi, WANG Xiaojun, et al. Synthesis and performance of ZnO quantum dots water-based fluorescent ink for anti-counterfeiting applications. Scientific Reports, 2021, 11: 5841], luminescent carbon materials [(6) JIANG Kai, WANG Yuhui, LI Zhongjun, et al. Afterglow of carbon dots: mechanism, strategy and applications. Materials Chemistry Frontiers, 2019, 4(2): 386-399; (7) BAKER S N, BAKER G A. Luminescent carbon nanodots: emergent nanolights. Angewandte Chemie International Edition, 2010, 49: 6726-6744], organic light-emitting materials, etc. [(8) AHANGER F A, NAZIR N, LONE M S, et al.Emission color tuning and white light generation from a trimolecular cocktail incationic micellar system with promising applicability in the anticounterfeiting technology. Langmuir, 2021, 37: 7730-7740; (9) HAN Jiangli, FENG Wenhui, MULETA Yadeta, et al. Small-molecule-doped organic crystals with long-persistent luminescence. Advanced Functional Materials, 2019, 29 (30): 1902503]. Among them, rare earth luminescent materials have stable physical and chemical properties, wide emission wavelength coverage, and narrow emission spectrum, making them the most ideal fluorescent anti-counterfeiting materials. Most of the rare earth luminescent materials currently used in fluorescent anti-counterfeiting technology are single / dual-color or single / dual-mode materials that can produce one or two luminescent colors under one or two specific wavelengths of excitation. The technical barriers of this type of luminescent material are not high, and there is a possibility of being replaced by substances with the same emission, so there is still a risk of being imitated and counterfeited. . Summary of the invention

[0004] The purpose of the present invention is to provide a multi-mode fluorescent anti-counterfeiting material and an anti-counterfeiting demonstration device. Compared with the above-mentioned single / dual mode, the multi-mode anti-counterfeiting material can greatly increase the difficulty of imitation, thereby greatly improving the anti-counterfeiting level.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] In one aspect, the present invention provides a multi-mode fluorescent anti-counterfeiting material, the molecular formula of which is Re 2 O 2 S:0.08Yb,0.02Er@Re 2 O 2 S: 0.05Tb, where Re = Y, Gd, La.

[0007] Furthermore, the material emits red light under 1530nm wavelength excitation. 3+ Ions do not emit light, Er in the nuclear layer 3+ The ions exhibit two sets of emission bands, red and green. Since the red band is much stronger than the green light, the overall light emission of the material is red.

[0008] Furthermore, the material emits green light under 254nm wavelength or X-ray excitation. 3+ The ions show strong green luminescence, and the Er in the nuclear layer 3+ The ion emission is very weak and is completely blocked by Tb 3+ The green emission of the ions is masked, so the overall emission color is green.

[0009] Furthermore, the material emits yellow light at 303K and 980nm wavelength. 3+ Ions do not emit light, Er in the nuclear layer 3+ The ions exhibit two sets of emission bands, red and green, but compared with the excitation at a wavelength of 1530nm, the green light emission is significantly enhanced and the ratio of red to green luminescence intensities decreases, resulting in an overall yellow luminescence color.

[0010] Furthermore, the material emits orange-red light under 980nm wavelength excitation at 513K. As the temperature increases from 303K to 513K, the green light intensity drops sharply, while the red light intensity changes only slightly, causing the overall luminescent color to change from yellow to orange-red.

[0011] Another aspect of the present invention provides a use of the multi-mode fluorescent anti-counterfeiting material in preparing anti-counterfeiting materials.

[0012] Using Re 2 O 2 S:0.08Yb,0.02Er@Re 2 O 2 Er in the core-shell structure of S:0.05Tb (Re=Y,Gd,La) material 3+ and Tb 3+ Ions exhibit different luminescent colors when excited by different wavelengths, and their luminescent colors also change with changes in temperature, achieving fluorescent anti-counterfeiting through different luminescent colors.

[0013] The present invention also provides an application of the multi-mode fluorescent anti-counterfeiting material in an anti-counterfeiting demonstration device.

[0014] The display device comprises a light-emitting layer and a substrate, wherein the light-emitting layer is prepared by dispersing the multi-mode fluorescent anti-counterfeiting material in a transparent medium containing an additive; the transparent medium is one or more of epoxy resin, acrylic resin, polyester resin, polyethylene resin, polyamide resin, perchlorethylene resin, polyvinyl chloride resin, ethylene-vinyl acetate copolymer resin, alkyd resin, and polymethyl methacrylate;

[0015] The additive is one or more of a curing agent, a stabilizer, a leveling agent, a defoaming agent, a plasticizer, a surfactant, a flame retardant, a pigment, and a surface modifier; the substrate is glass, ceramic, aluminum foil, tin foil, tin-plated plate, aluminum plate, stainless steel plate, polyester plate, polypropylene plate, polyvinyl chloride plate or polyethylene plate.

[0016] The beneficial effects of the present invention are:

[0017] The Re provided by the present invention 2 O 2 S:0.08Yb,0.02Er@Re 2 O 2 S:0.05Tb (Re = Y, Gd, La) anti-counterfeiting material presents different luminescent colors at 1530nm, 980nm, 254nm (or X-ray) and at different temperatures. Compared with the single / dual mode materials that can produce one or two luminescent colors under one or two specific wavelengths, it has a higher anti-counterfeiting level and is difficult to be replaced and forged, greatly improving the security of anti-counterfeiting. At the same time, the present invention uses rare earth sulfur oxides with excellent luminescent properties as the matrix, has the characteristics of stable physical and chemical properties, non-toxicity, excellent optical properties, etc., and is suitable for anti-counterfeiting applications of daily necessities.

[0018] The anti-counterfeiting demonstration device provided by the present invention can display two-dimensional luminous images of different colors under the excitation of 1530nm, 980nm and 254nm (or X-rays), and can be applied to experimental teaching in colleges and universities. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: emission spectrum of 0.05Tb under 980nm excitation;

[0020] Figure 2 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: Emission spectrum of 0.05Tb under 1530nm excitation;

[0021] Figure 3 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: Emission spectrum of 0.05Tb under 254nm excitation;

[0022] Figure 4 Y2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: Emission spectrum of 0.05Tb under X-ray excitation;

[0023] Figure 5 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: luminescence color coordinates of 0.05Tb under different wavelength excitation;

[0024] Figure 6 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: Emission spectrum of 0.05Tb as it changes with temperature (excitation wavelength is 980nm);

[0025] Figure 7 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S:0.05Tb luminescence color coordinates changing with temperature (excitation wavelength is 980nm). DETAILED DESCRIPTION

[0026] The following are embodiments of the present invention. It should be noted that the present invention is not limited to these embodiments.

[0027] Example 1

[0028] A multi-mode fluorescent anti-counterfeiting material with the molecular formula Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: 0.05Tb, the preparation method is as follows:

[0029] (1) Take 90 ml of Y(NO 3 ) 3 (0.1mol / L), 8ml Yb(NO 3 ) 3 (0.1 mol / L) and 2 ml Er(NO 3 ) 3(0.1mol / L) solution was mixed with deionized water to obtain 200ml rare earth nitrate mixed solution, and 1mol urea was dissolved in deionized water to prepare 800ml urea solution. The above two solutions were heated to 60°C respectively, and then mixed to prepare a mixed solution with a volume of 1000ml, and then continued to heat to 85°C. When the mixed solution was observed to be turbid, it was continued to mature for 1.5h to obtain a precursor precipitate 1. After that, the precipitate was centrifuged and ultrasonically washed with deionized water and anhydrous ethanol respectively, and then dried at 40°C for 12h. The dried precursor powder was placed in a resistance furnace and calcined at 600°C for 1h to obtain Y 2 O 3 :0.08Yb,0.02Er powder;

[0030] (2) Take 95 ml of Y(NO 3 ) 3 (0.1 mol / L) and 5 ml Tb(NO 3 ) 3 (0.1 mol / L) solution was mixed with deionized water to obtain 200 ml of rare earth nitrate mixed solution. 1 mol of urea was dissolved in deionized water to obtain 800 ml of urea solution. The above two solutions were heated to 60° C. respectively and then mixed to obtain a mixed solution with a volume of 1000 ml. Y prepared in step (1) was added to the mixture. 2 O 3 :0.08Yb, 0.02Er powders were ultrasonically dispersed in the mixed solution, and then the mixed solution was heated to 85°C and aged for 30 minutes to obtain a precursor precipitate 2. The precipitate was centrifuged, washed, dried, and annealed at 600°C for 1 hour to obtain a core-shell structured Y 2 O 3 :0.08Yb,0.02Er@Y 2 O 3 :0.05Tb powder;

[0031] (3) Spread the core-shell structure powder obtained in step (2) in a quartz boat and place it at the bottom of the quartz tube. Take another quartz boat and place an appropriate amount of sulfur powder in the quartz tube. Place it at an appropriate position in the quartz tube. Pass argon gas through the quartz tube for 40 minutes to exhaust the air. Then place the quartz tube in a resistance furnace at 800°C. Control the sulfur vapor by controlling the argon flow rate. After sulfurization for 1 hour, take out the quartz tube and cool it to room temperature to finally obtain Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: 0.05Tb powder.

[0032] An application of the multi-mode fluorescent anti-counterfeiting material in an anti-counterfeiting demonstration device, the anti-counterfeiting demonstration device includes a light-emitting layer and a substrate, and the preparation method thereof is as follows:

[0033] The above Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: 0.05Tb powder, epoxy resin, leveling agent and defoaming agent are added to a high-speed mixer for mechanical mixing. After all materials are mixed evenly, they are coated on an aluminum plate and heat-treated to form a luminescent layer. The luminescent layer is assembled on a substrate to obtain an anti-counterfeiting demonstration device. Since the substrate is made of a material with excellent thermal conductivity, the luminescent layer can withstand high excitation power irradiation.

[0034] Figure 1 , Figure 2 , Figure 3 and Figure 4 Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: Emission spectra of 0.05Tb sample under 980nm, 1530nm, 254nm and X-ray excitation, Figure 5 is the corresponding luminous color coordinate.

[0035] Under 980nm and 1530nm wavelength excitation, the sample only shows Er in the nucleus. 3+ The red and green light of the ions are emitted, but the relative intensities of the red and green lights are different, resulting in the overall luminescence colors of the samples being yellow and red, respectively. Under 254nm wavelength or X-ray excitation, the Er in the nucleus 3+ The ion light emission is very weak and is completely covered by the outer layer of Tb 3+ The green emission of the ions is masked, so the overall emission color is green.

[0036] Figure 6 Under the excitation of 980nm wavelength, Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S: The emission spectrum of 0.05Tb sample changes with temperature, Figure 7 The luminescent color coordinates at different temperatures are given.

[0037] It can be seen that as the temperature increases from 303K to 513K, the green light emission intensity of the sample drops sharply, while the red light intensity changes only slightly, causing the overall luminescent color to change from yellow to orange-red.

[0038] In this embodiment, the rare earth element in the matrix can be one or more combinations of Y, Gd, and La, which has no effect on the final product.

[0039] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the implementation methods. The protection scope of the present invention shall be subject to the scope defined by the claims. Other different forms of changes or modifications may be made based on the above description. Obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A multi-mode fluorescent anti-counterfeiting material, It is characterized in that The molecular formula of the material is Y 2 O 2 S:0.08Yb,0.02Er@Y 2 O 2 S:0.05Tb.

2. The multi-mode fluorescent anti-counterfeiting material according to claim 1, It is characterized in that The material emits red light when excited at a wavelength of 1530 nm.

3. The multi-mode fluorescent anti-counterfeiting material according to claim 1, It is characterized in that The material emits green light under 254 nm wavelength or X-ray excitation.

4. The multi-mode fluorescent anti-counterfeiting material according to claim 1, It is characterized in that The material emits yellow light at a temperature of 303K and under excitation at a wavelength of 980nm.

5. The multi-mode fluorescent anti-counterfeiting material according to claim 1, It is characterized in that The material emits orange-red light at a temperature of 513K and under excitation at a wavelength of 980nm.

6. Use of the multi-mode fluorescent anti-counterfeiting material according to any one of claims 1 to 5 in an anti-counterfeiting demonstration device.

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