Ambient light regulated up-conversion ultraviolet luminescent material and preparation method and application thereof in anti-counterfeiting
By using rare-earth ion-doped ambient light to modulate upconversion ultraviolet luminescent materials, and utilizing the synergistic excitation of infrared light and ambient light to achieve reversible switching control of ultraviolet emission, this technology solves the problems of low ultraviolet emission efficiency and regulation in existing technologies, and provides a highly secure and easily mass-producible anti-counterfeiting solution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-04-03
AI Technical Summary
Existing upconversion luminescent materials are difficult to achieve efficient ultraviolet emission and have poor stability. They also lack external control mechanisms. Traditional ultraviolet excitation anti-counterfeiting technologies are easy to imitate and cannot meet the requirements of high security and intelligence.
Upconversion ultraviolet luminescent materials with ambient light modulation are used. By doping with rare earth ions Tm3+ and Er3+, reversible switching control of ultraviolet emission is achieved by synergistic excitation of infrared light and ambient light. The preparation methods include solid-state method, hydrothermal method or sol-gel method.
It achieves real-time reversible switching control of upconversion ultraviolet luminescence, has good material cycle stability, high anti-counterfeiting level, is difficult to imitate, and is suitable for mass production.
Smart Images
Figure CN121780164A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of luminescent materials and anti-counterfeiting technology, specifically relating to an upconversion ultraviolet luminescent material with ambient light modulation, its preparation method, and its application in anti-counterfeiting. Background Technology
[0002] Upconversion luminescent materials, as a class of functional materials capable of converting low-energy photons into high-energy photons, have shown broad application prospects in various fields such as bioimaging, optoelectronic devices, and anti-counterfeiting due to their unique anti-Stokes luminescence properties. Among them, infrared-excited upconversion luminescent materials have become a current research hotspot due to the advantages of infrared light, such as strong penetration, minimal damage to organisms, and low environmental interference. In existing technologies, most upconversion luminescent materials use a single near-infrared light (such as 980nm or 808nm wavelength infrared light) as the excitation source, and rare earth ions (such as Yb) are used as the excitation source. 3+ Er 3+ Ho 3+ Visible light (400~760nm) emission is achieved through energy level transitions (e.g., energy transfer upconversion or excited state absorption processes). However, existing upconversion luminescent materials and related application technologies still face several challenges: Firstly, achieving ultraviolet emission is difficult. Ultraviolet light (conventional wavelength 200-400nm) possesses high photon energy, strong chemical activity, and good concealment, giving it irreplaceable advantages in high-precision anti-counterfeiting scenarios. However, because ultraviolet photon energy is higher than visible light, generating ultraviolet emission under single infrared excitation requires multiple energy accumulation steps or high-order multiphoton processes, resulting in typically extremely low luminous efficiency and stability that fails to meet practical application requirements. The few reported upconversion ultraviolet luminescent materials often require high-intensity infrared excitation and suffer from short luminescence lifetimes and poor stability, hindering large-scale applications. Secondly, there is a lack of effective external control mechanisms. Once the luminescence process of existing upconversion luminescent materials is initiated by the excitation source, key parameters such as luminescence intensity and emission wavelength are difficult to dynamically control using simple and convenient external means. To shut down luminescence, the excitation source must be cut off, a "one-size-fits-all" approach lacking flexibility. This lack of a control mechanism severely limits upconversion luminescent materials in scenarios requiring precise control of emission timing and switching states (such as dynamic anti-counterfeiting and intelligent sensing), making them unsuitable for the multifunctional needs of complex applications. Thirdly, traditional ultraviolet excitation anti-counterfeiting technology is widely used in tickets, certificates, and product packaging due to its intuitive and easily identifiable characteristics. However, most of these traditional anti-counterfeiting technologies rely on a static "single ultraviolet excitation-visible fluorescence emission" model, and their principles are readily available. Counterfeiters can replicate these technologies by imitating similar fluorescent materials or excitation sources, resulting in insufficient anti-counterfeiting security and making it difficult to curb counterfeiting. In summary, existing upconversion luminescent materials face significant bottlenecks in achieving efficient ultraviolet emission and dynamic external control, while traditional static fluorescence anti-counterfeiting technologies are easily counterfeited. These factors collectively restrict the development of highly secure and intelligent ultraviolet anti-counterfeiting technologies. Summary of the Invention
[0003] The purpose of this invention is to provide an ambient light-controlled upconversion ultraviolet luminescent material, its preparation method, and its application. The ambient light-controlled upconversion ultraviolet luminescent material provided by this invention can easily control the ultraviolet emission switch state through ambient light, realizing real-time and reversible switching control of upconversion ultraviolet luminescence; at the same time, it has the characteristics of good cycle stability and high anti-counterfeiting level, and can be mass-produced, with important practical application value and market prospects.
[0004] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an ambient light-modulated upconversion ultraviolet luminescent material, comprising an inorganic luminescent matrix and rare earth ions doped in the inorganic luminescent matrix; the rare earth ions include Tm 3+ or including Tm 3+ and Er 3+ .
[0005] Preferably, the rare earth ions also include Gd. 3+ and / or Bi 3+ .
[0006] Preferably, the Tm 3+ The doping concentration is 0.1~5 mol%; the Er 3+ The doping concentration is 0.1~10 mol.
[0007] Preferably, the Gd 3+ The doping concentration is 0.1~60 mol%; the Bi 3+ The doping concentration is 0.1~10 mol.
[0008] Preferably, the inorganic luminescent matrix comprises fluorides and / or oxides.
[0009] The present invention provides a method for preparing upconversion ultraviolet luminescent materials with ambient light modulation as described in the above technical solution, including solid-phase method, hydrothermal method or sol-gel method.
[0010] This invention provides the application of the ambient light-modulated upconversion ultraviolet luminescent material described above in anti-counterfeiting.
[0011] This invention provides an ultraviolet anti-counterfeiting method based on an ambient light switch. The anti-counterfeiting pattern is formed using an upconversion ultraviolet luminescent material with ambient light control as described in the above technical solution. When the ambient light is on, the anti-counterfeiting pattern is illuminated by an infrared light source, and the anti-counterfeiting pattern emits ultraviolet light and becomes visible. When the ambient light is off, the ultraviolet light emission of the anti-counterfeiting pattern disappears and becomes hidden.
[0012] The present invention provides an ultraviolet anti-counterfeiting product, including a substrate and an anti-counterfeiting pattern layer formed on the substrate, wherein the anti-counterfeiting pattern layer includes an upconversion ultraviolet luminescent material with ambient light modulation as described in the above technical solution.
[0013] The present invention provides a method for preparing the ultraviolet anti-counterfeiting product described in the above technical solution, wherein an anti-counterfeiting pattern layer is prepared on the substrate, and the method for preparing the anti-counterfeiting pattern layer includes one or more of printing, coating, transfer and embedding.
[0014] This invention provides an ambient light-modulated upconversion ultraviolet luminescent material, comprising an inorganic luminescent matrix and rare earth ions doped in the inorganic luminescent matrix; the rare earth ions include Tm 3+ or including Tm 3+ and Er 3+ The ambient light-modulated upconversion ultraviolet luminescent material provided by this invention utilizes Tm 3+ Single doping or Tm 3+ -Er 3+ Co-doping, under infrared light (800nm or 1530nm) irradiation, allows the visible light component of ambient light to serve as the second-step energy for the excited-state absorption process, co-exciting Tm. 3+ Ions produce ultraviolet emission. When ambient light is off, infrared light alone cannot excite ultraviolet emission using the ambient light-controlled upconversion ultraviolet luminescent material provided by this invention, thus forming a switching mechanism. The specific excitation path of the ambient light-controlled upconversion ultraviolet luminescent material provided by this invention is as follows: using 800nm to excite Tm 3+ of 3 H4 energy level, or Er excitation at 1530 nm. 3+ of 4 I 13 / 2 Energy level (energy transferred to Tm) 3+ Under the synergistic excitation of ambient visible light, Tm 3+ stimulated to 1 D2 or 1The I6 energy level generates ultraviolet emission. Based on this, the present invention provides an ultraviolet anti-counterfeiting pattern designed with an ambient light-controlled upconversion ultraviolet luminescent material: the ultraviolet luminescent pattern is detectable in the presence of infrared irradiation and ambient light; the ultraviolet anti-counterfeiting pattern is undetectable in the absence of ambient light. Compared with the prior art, the present invention has the following advantages: it achieves real-time, reversible switching control of upconversion ultraviolet luminescence; the material has good luminescence cycle stability; it has a high anti-counterfeiting level that cannot be counterfeited by ordinary banknote detectors; at the same time, the material preparation process is mature and easy to mass-produce.
[0015] In summary, the ambient light-controlled upconversion ultraviolet luminescent material provided by this invention has the advantages of not requiring complex equipment, simple operation, low cost, strong concealment, resistance to copying, and high anti-counterfeiting level when applied to ultraviolet anti-counterfeiting.
[0016] In this invention, the rare earth ions also include Gd. 3+ and / or Bi 3+ The present invention provides an upconversion ultraviolet luminescent material with ambient light modulation by further introducing Gd... 3+ Or Bi 3+ Ions can extend the ultraviolet emission wavelength of materials, making them more widely used in ultraviolet anti-counterfeiting. Attached Figure Description
[0017] Figure 1 A schematic diagram of the upconversion ultraviolet emission mechanism of the ambient light-controlled upconversion ultraviolet luminescent material provided by the present invention under different combinations of rare earth ions; Figure 2 The upconversion ultraviolet luminescent material for ambient light regulation provided by this invention exhibits an upconversion ultraviolet emission spectrum under synergistic excitation by infrared irradiation and ambient lighting. Detailed Implementation
[0018] This invention provides an ambient light-modulated upconversion ultraviolet luminescent material, comprising an inorganic luminescent matrix and rare earth ions doped in the inorganic luminescent matrix; the rare earth ions include Tm 3+ or including Tm 3+ and Er 3+ .
[0019] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.
[0020] The upconversion ultraviolet luminescent material provided by this invention, when excited by 800nm or 1530nm infrared light, has its ultraviolet emission intensity modulated by the ambient visible light component in the ambient light.
[0021] The ambient light-modulated upconversion ultraviolet luminescent material provided by this invention comprises an inorganic luminescent matrix. In this invention, the inorganic luminescent matrix preferably comprises fluorides and / or oxides. The fluorides preferably comprise NaYF4. The oxides preferably comprise Y3Al5O 12 .
[0022] The ambient light-modulated upconversion ultraviolet luminescent material provided by this invention comprises rare earth ions doped in the inorganic luminescent matrix. In this invention, the rare earth ions include Tm... 3+ (i.e., Tm) 3+ (Single-doped inorganic luminescent matrix). Alternatively, the rare earth ions include Tm. 3+ and Er 3+ (i.e., Tm) 3+ -Er 3+ (Co-doped inorganic luminescent matrix).
[0023] In this invention, the Tm 3+ The preferred doping concentration is 0.1~5 mol%, and in the examples it can be 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5 mol%. The Er 3+ The doping concentration is preferably 0.1~10 mol%, and in the examples it can be 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mol.
[0024] In this invention, the rare earth ions preferably also include Gd. 3+ and / or Bi 3+ In the example, Gd 3+ Or Bi 3+ The Gd 3+ The doping concentration is preferably 0.1~60 mol%, and in the examples it can be 0.1, 0.5, 1, 5, 10, 20, 30, 50 or 60 mol%. The Bi 3+ The doping concentration is preferably 0.1~10 mol%, and in the examples it can be 0.1, 0.5, 1, 2, 3, 4, 5 or 10 mol.
[0025] In specific embodiments of the present invention, examples of the ambient light-modulated upconversion ultraviolet luminescent material include: Y3Al5O 12 2%Tm 3+ NaYF4:2%Tm 3+ ,2%Er 3+ Y3Al5O 12 2%Tm 3+ 40%Gd 3+ and Y3Al5O 12 2%Tm 3+ 1%Bi3+ .
[0026] Figure 1 A schematic diagram of the upconversion ultraviolet emission mechanism of the ambient light-modulated upconversion ultraviolet luminescent material provided by the present invention under different ion combination conditions; Figure 1 Tm is shown from left to right. 3+ Single-doped systems, and Tm 3+ -Er 3+ Tm 3+ -Gd 3+ Tm 3+ -Bi 3+ Ion co-doped system. (From) Figure 1 It is known that, under the synergistic excitation of infrared irradiation and ambient visible light, the luminescent ions of the ambient light-controlled upconversion ultraviolet luminescent material provided by this invention generate multi-band ultraviolet emission.
[0027] Figure 2 The upconversion ultraviolet luminescent material for ambient light regulation provided by this invention exhibits an upconversion ultraviolet emission spectrum under synergistic excitation by infrared irradiation and ambient lighting. Figure 2 The solid line in the image represents the upconversion ultraviolet emission spectrum of the upconversion ultraviolet luminescent material under the synergistic excitation of infrared irradiation and ambient lighting. Figure 2 The dashed line in the figure represents the results of the control group, which is the upconversion ultraviolet emission spectrum of the upconversion ultraviolet luminescent material under infrared irradiation excitation. Figure 2 Ambient light (AL) in this context refers to indoor lighting with an illuminance of 1500 lux. Figure 2 The samples from top to bottom and their corresponding excitation conditions are: Y3Al5O 12 2%Tm 3+ (800nm + AL), NaYF4:2%Tm 3+ ,2%Er 3+ (1530nm + AL), Y3Al5O 12 2%Tm 3+ 40%Gd 3+ (800nm + AL) and Y3Al5O 12 2%Tm 3+ 1%Bi 3+ (800nm + AL). With Figure 2 The comparison with the control group showed that, under infrared excitation only and without ambient light, no ultraviolet emission was detected in any of the samples (e.g., Figure 2 (The dashed curve data in the image).
[0028] The excitation conditions of the ambient light-controlled upconversion ultraviolet luminescent material provided by the present invention are synergistic excitation of infrared light and ambient visible light; the ultraviolet emission wavelength of the ambient light-controlled upconversion luminescent material is preferably 365nm, 290nm, 345nm, 310nm or 305nm.
[0029] This invention provides a method for preparing ambient light-modulated upconversion ultraviolet luminescent materials as described in the above-mentioned technical solution, including a solid-state method, a hydrothermal method, or a sol-gel method. This invention does not impose special requirements on the specific implementation methods of the solid-state method, hydrothermal method, or sol-gel method.
[0030] This invention provides the application of the ambient light-modulated upconversion ultraviolet luminescent material described above in anti-counterfeiting.
[0031] The ambient light-controlled upconversion ultraviolet luminescent material provided by this invention uses ambient light as a "switch" for upconversion excitation (the principle is that the visible light component in ambient light serves as the second energy source for the excited state absorption process), thus distinguishing it from traditional single infrared-excited upconversion luminescent materials.
[0032] The ultraviolet anti-counterfeiting mechanism of the upconversion ultraviolet luminescent material with ambient light control provided by this invention is: infrared irradiation + ambient light switch, to realize the visibility of ultraviolet patterns.
[0033] This invention provides an ultraviolet anti-counterfeiting method based on an ambient light switch. The anti-counterfeiting pattern is formed using an upconversion ultraviolet luminescent material with ambient light control as described in the above technical solution. When the ambient light is on, the anti-counterfeiting pattern is illuminated by an infrared light source, and the anti-counterfeiting pattern emits ultraviolet light and becomes visible. When the ambient light is off, the ultraviolet light emission of the anti-counterfeiting pattern disappears and becomes hidden.
[0034] In this invention, the wavelength of the infrared light source is preferably 800 nm or 1530 nm. The power density of the infrared light source is preferably 0.2 W / cm². 2 .
[0035] In this invention, the ambient light is preferably visible light with a wavelength of 400-700 nm, and in the embodiments, it can be ordinary indoor lighting source. The intensity of the ambient light is preferably 50-5000 lux, more preferably 100-4500 lux, and in the embodiments, it can be 1500 lux.
[0036] This invention provides an ultraviolet anti-counterfeiting product, comprising a substrate and an anti-counterfeiting pattern layer formed on the substrate, wherein the anti-counterfeiting pattern layer comprises an ambient light-controlled upconversion ultraviolet luminescent material as described in the above-mentioned technical solution. The ultraviolet anti-counterfeiting product provided by this invention uses an infrared light source to excite the anti-counterfeiting pattern layer under ambient light conditions.
[0037] This invention provides a method for preparing the ultraviolet anti-counterfeiting product described in the above technical solution. An anti-counterfeiting pattern layer is prepared on the substrate, and the preparation method of the anti-counterfeiting pattern layer includes one or more of printing, coating, transfer, and embedding. This invention does not have specific requirements for the specific implementation of the printing, coating, transfer, or embedding methods. In this invention, the printing can be screen printing. The screen printing method preferably includes: mixing the ambient light-controlled upconversion ultraviolet luminescent material described in the above technical solution with ink and then performing screen printing. The ink can be a transparent ink.
[0038] This invention provides an ultraviolet anti-counterfeiting system, comprising an ultraviolet anti-counterfeiting product and an infrared light source; the ultraviolet anti-counterfeiting product includes a substrate and an anti-counterfeiting pattern layer formed on the substrate, the anti-counterfeiting pattern layer comprising an upconversion ultraviolet luminescent material regulated by ambient light as described in the above-mentioned technical solution. The infrared light source is used to excite the anti-counterfeiting pattern layer.
[0039] In this invention, the ultraviolet anti-counterfeiting system preferably further includes an ultraviolet detection module and an ambient light control module.
[0040] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0041] Example 1: Tm 3+ -Er 3+ Preparation of co-fluoride materials NaYF4:2%Tm was prepared by hydrothermal method 3+ ,2%Er 3+ Nanoparticles. The specific hydrothermal method involves dissolving rare earth nitrates and sodium fluoride in a stoichiometric ratio, transferring the solutions to a high-pressure reactor, and reacting at 180°C for 24 hours. The resulting product is resistant to infrared light at 1530 nm (power density 0.2 W / cm²). 2 When the ambient light (1500 lux ambient white light) is turned on, 365 nm ultraviolet emission can be observed; when the ambient light is turned off, the 365 nm emission intensity completely disappears.
[0042] Example 2: Tm 3+ -Gd 3+ Preparation of co-doped oxide materials Y3Al5O prepared by solid-state method 12 2%Tm 3+ 40%Gd 3+ In 800nm infrared light (0.2W / cm²), 2When the ambient light (1500 lux ambient white light) is turned on, dual-band ultraviolet emission of 310 nm and 365 nm can be observed; when the ambient light is turned off, the emission intensity of dual-band ultraviolet emission of 310 nm and 365 nm completely disappears.
[0043] Example 3: Production of Anti-counterfeiting Labels The material prepared in Example 1 was mixed with transparent ink, and a preset pattern was printed on a plastic substrate using screen printing technology to obtain an anti-counterfeiting label. When the anti-counterfeiting label is used, it is illuminated with a 1530nm infrared flashlight. Under ambient light (1500 lux ambient white light), the pattern shows ultraviolet fluorescence, and the pattern disappears when the indoor light is turned off.
[0044] As can be seen from the above embodiments, the ambient light-controlled upconversion ultraviolet luminescent material provided by the present invention utilizes the visible light component in ambient light as a "light switch" for the upconversion process, and controls the process through dual excitation conditions of "infrared light + ambient light" in rare earth Tm 3+ This invention enables controllable switching on / off of ultraviolet emission in a doped material system, creating a novel dynamic anti-counterfeiting method. Specifically, under ambient light conditions, the ambient light-controlled upconversion ultraviolet luminescent material provided by this invention produces ultraviolet emission (365nm or 290 / 345nm); under off-light conditions, infrared light alone cannot excite ultraviolet emission. The ambient light-controlled upconversion ultraviolet luminescent material provided by this invention is applied to ultraviolet anti-counterfeiting: under infrared irradiation, a preset ultraviolet luminescent pattern is visible when the light is on, but invisible when the light is off, achieving high-security ultraviolet anti-counterfeiting.
[0045] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. An upconversion ultraviolet luminescent material regulated by ambient light, characterized in that, It includes an inorganic light-emitting matrix and rare earth ions doped in the inorganic light-emitting matrix; the rare earth ions include Tm 3+ or including Tm 3+ and Er 3+ .
2. The upconversion ultraviolet luminescent material with ambient light modulation according to claim 1, characterized in that, The rare earth ions also include Gd. 3+ and / or Bi 3+ .
3. The upconversion ultraviolet luminescent material for ambient light modulation according to claim 1, characterized in that, The Tm 3+ The doping concentration is 0.1~5 mol%; the Er 3+ The doping concentration is 0.1~10 mol.
4. The ambient light-modulated upconversion ultraviolet luminescent material according to claim 2, characterized in that, The Gd 3+ The doping concentration is 0.1~60 mol%; the Bi 3+ The doping concentration is 0.1~10 mol.
5. The ambient light-modulated upconversion ultraviolet luminescent material according to any one of claims 1 to 4, characterized in that, The inorganic luminescent matrix includes fluorides and / or oxides.
6. The method for preparing the ambient light-modulated upconversion ultraviolet luminescent material according to any one of claims 1 to 5, characterized in that, This includes solid-phase methods, hydrothermal methods, or sol-gel methods.
7. The application of the ambient light-modulated upconversion ultraviolet luminescent material according to any one of claims 1 to 5 in anti-counterfeiting.
8. A UV anti-counterfeiting method based on an ambient light switch, characterized in that, An anti-counterfeiting pattern is formed using an upconversion ultraviolet luminescent material with ambient light control as described in any one of claims 1 to 5. When the ambient light is on, the anti-counterfeiting pattern emits ultraviolet light and becomes visible when irradiated with an infrared light source; when the ambient light is off, the ultraviolet light emission of the anti-counterfeiting pattern disappears and becomes hidden.
9. A UV anti-counterfeiting product, characterized in that, It includes a substrate and an anti-counterfeiting pattern layer formed on the substrate, wherein the anti-counterfeiting pattern layer includes an upconversion ultraviolet luminescent material regulated by ambient light as described in any one of claims 1 to 5.
10. The method for preparing the ultraviolet anti-counterfeiting product according to claim 9, characterized in that, An anti-counterfeiting pattern layer is prepared on the substrate, and the preparation method of the anti-counterfeiting pattern layer includes one or more of printing, coating, transfer and embedding.