Adjustable dual-mode luminescent phosphor, preparation method thereof and anti-counterfeiting application

Abstract

This invention provides a tunable dual-mode luminescent phosphor, its preparation method, and its anti-counterfeiting application. The chemical formula of the tunable dual-mode luminescent phosphor is LiIn. 1‑x‑y+xy Sc x‑xy GeO 4 :yBi 3+ Where 0≤x≤0.5, 0.002≤y≤0.02. The tunable dual-mode luminescent phosphor provided by this invention has high stability and will not deliquesce even after being placed in air for a long time. Under ultraviolet light excitation, by adjusting the atomic ratio of Sc to In in the phosphor components, the emission color from orange-yellow light to blue light can be continuously adjusted. At the same time, the afterglow emission time is adjustable, and a visible afterglow time of 0-10s can be maintained after excitation stops.

Description

A tunable dual-mode luminescent phosphor, its preparation method and anti-counterfeiting application Technical Field

[0001] This invention belongs to the field of fluorescent materials technology, and relates to a fluorescent powder, particularly a tunable dual-mode luminescent fluorescent powder, its preparation method, and its anti-counterfeiting application. Background Technology

[0002] With the continuous development of technology, protecting products from counterfeiting and imitation has become increasingly important. The existence of counterfeit products disrupts market order, causes huge economic losses to both businesses and consumers, and can even threaten people's lives and health.

[0003] Fluorescent materials are special materials that emit visible light under an excitation light source. In anti-counterfeiting applications, fluorescent materials typically offer advantages such as simple synthesis processes, good visual visibility, convenient identification, and low cost, making them a common anti-counterfeiting method. However, some fluorescent powders currently used for anti-counterfeiting have fixed emission colors, a single emission mode, and are easy to crack.

[0004] CN102337130A discloses bismuth ion-doped germanium silicate luminescent materials and their preparation methods, with the general chemical formula AB. 1-x Bi x CO4, in which A is one of Na, K, or Li, B is one or two of Y, Gd, Lu, La, or Sc, and C is one or two of Ge or Si, emits blue-white light when excited at a wavelength of 350 nm. It has good luminescence stability and is suitable for use in UV-LEDs. However, its luminescence color is not adjustable and it only has a single luminescence mode, making it unsuitable for anti-counterfeiting purposes.

[0005] CN115926793A discloses a multi-response anti-counterfeiting germanate phosphor with adjustable luminescence color, its preparation method, and its application. The chemical formula of this phosphor is Ca3Y. 2-0.01-y Ge3O 12 1.0% Bi 3+ ,yEr 3+ This phosphor exhibits a dynamic process of color change based on ambient temperature variations. However, it requires excitation from both ultraviolet and 980nm light sources to achieve color adjustment, making the process complex and impractical. Furthermore, this phosphor lacks afterglow emission characteristics.

[0006] Therefore, there is an urgent need to develop new anti-counterfeiting fluorescent powders with multi-dimensional composite luminescence and adjustable luminescence characteristics to increase the complexity of cracking and improve the level of anti-counterfeiting security. Summary of the Invention

[0007] The purpose of this invention is to provide an adjustable dual-mode luminescent phosphor, its preparation method, and its anti-counterfeiting application. This phosphor has dual-mode luminescence characteristics, and its luminescence color and afterglow luminescence time are adjustable, solving the problems of fixed luminescence color and single luminescence mode of existing phosphors used for anti-counterfeiting.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a tunable dual-mode luminescent phosphor, wherein the chemical formula of the tunable dual-mode luminescent phosphor is LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , where 0≤x≤0.5, 0.002≤y≤0.02.

[0010] The tunable dual-mode luminescent phosphor provided by this invention uses Bi 3+ As the luminescent center, the phosphor matrix is ​​mainly composed of germanate. By replacing some of the In elements in the phosphor matrix with Sc elements, the electronic structure of the phosphor matrix is ​​changed, thereby reducing the optical band gap of the phosphor matrix and thus regulating the fluorescence luminescence characteristics.

[0011] Adjustable means that the emission color and afterglow time can be adjusted, and dual-mode emission means that it has two emission modes: steady-state emission and afterglow emission.

[0012] The tunable dual-mode luminescent phosphor provided by this invention has high stability and will not deliquesce even after being placed in air for a long time. Under ultraviolet light excitation, by adjusting the atomic ratio of Sc to In in the phosphor components, the emission color can be continuously adjusted from orange-yellow light to blue light, and the afterglow emission time can also be adjusted.

[0013] In the chemical formula of the tunable dual-mode luminescent phosphor, 0 ≤ x ≤ 0.5, for example, it can be 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] In the chemical formula of the tunable dual-mode luminescent phosphor, 0.002≤y≤0.02, for example, it can be 0.002, 0.004, 0.005, 0.006, 0.008, 0.01, 0.012, 0.014, 0.015, 0.016, 0.018 or 0.02, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Where 1-x-y+xy is 0.49-0.998, for example, it can be 0.49, 0.499, 0.5, 0.55, 0.588, 0.5988, 0.6, 0.65, 0.686, 0.6986, 0.7, 0.75, 0.784, 0.7984, 0.8, 0.85, 0.882, 0.8982, 0.9, 0.95, 0.98 or 0.998, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Where x-xy is 0-0.499, for example, it can be 0, 0.05, 0.098, 0.0998, 0.1, 0.15, 0.196, 0.1996, 0.2, 0.25, 0.294, 0.2994, 0.3, 0.35, 0.392, 0.3992, 0.4, 0.45, 0.49 or 0.499, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, in the tunable dual-mode luminescent phosphor, the atomic ratio of In to Sc, In / Sc, is (0.998-0.49):(0-0.499), for example, it can be 0.998:0, 0.98:0, 0.9:0.1, 0.8982:0.0998, 0.882:0.098, 0.8:0.2, 0.7984:0.1996, 0.784:0.196, 0.7:0.3, 0.6986:0.2994, 0.686:0.294, 0.6:0.4, 0.5988:0.3992, 0.588:0.392, 0.499:0.499, or 0.49:0.49, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the excitation wavelength of the tunable dual-mode phosphor is 240-322nm, for example, it can be 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm or 322nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the emission wavelength of the tunable dual-mode phosphor is 484nm-580nm, for example, it can be 484nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm or 580nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0020] Preferably, the afterglow emission time of the adjustable dual-mode phosphor is 0-10s, for example, it can be 0.1s, 0.5s, 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s or 10s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] In a second aspect, the present invention provides a method for preparing the tunable dual-mode luminescent phosphor described in the first aspect, the method comprising the following steps:

[0022] The raw materials, namely Li source, In source, Sc source, Ge source and Bi source, are mixed and then calcined.

[0023] Preferably, the Li source includes lithium carbonate.

[0024] Preferably, the In source comprises indium oxide.

[0025] Preferably, the Sc source comprises scandium oxide.

[0026] Preferably, the Ge source comprises germanium dioxide.

[0027] Preferably, the Bi source comprises bismuth trioxide.

[0028] Preferably, the mixing method includes: mixing and grinding the raw materials with anhydrous ethanol.

[0029] Preferably, the roasting temperature is 1100-1200℃, for example, it can be 1100℃, 1120℃, 1140℃, 1150℃, 1160℃, 1180℃ or 1200℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0030] Preferably, the roasting time is 4-8 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the roasting is followed by cooling and grinding.

[0032] Thirdly, the present invention provides an application of the tunable dual-mode luminescent phosphor described in the first aspect, wherein the tunable dual-mode luminescent phosphor is used for optical anti-counterfeiting.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The tunable dual-mode luminescent phosphor provided by this invention has high stability and will not deliquesce even after being placed in air for a long time. Under ultraviolet light excitation, by adjusting the atomic ratio of Sc to In in the phosphor components, the emission color can be continuously adjusted from orange-yellow light to blue light. At the same time, the afterglow emission time is adjustable, and a visible afterglow time of 0-10s can be maintained after excitation stops. Attached Figure Description

[0035] Figure 1 is the X-ray diffraction pattern of the tunable dual-mode luminescent phosphor provided in Examples 1-6;

[0036] Figure 2 shows the emission spectra of the tunable dual-mode luminescent phosphors provided in Examples 1-6;

[0037] Figure 3 is a CIE color coordinate diagram of the tunable dual-mode luminescent phosphors provided in Examples 1-6;

[0038] Figure 4 is a diagram of the afterglow time of the tunable dual-mode luminescent phosphors provided in Examples 1-6;

[0039] Figure 5 is an example of the anti-counterfeiting application of tunable dual-mode luminescent phosphor provided in Application Example 1. Detailed Implementation

[0040] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0041] Example 1

[0042] This embodiment provides a tunable dual-mode luminescent phosphor, the chemical formula of which is LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , where x = 0, y = 0.002.

[0043] The preparation method of the tunable dual-mode luminescent phosphor includes the following steps:

[0044] (1) Weigh lithium carbonate (Li2CO3), indium oxide (In2O3), scandium oxide (Sc2O3), germanium dioxide (GeO2), and bismuth trioxide (Bi2O3) according to the stoichiometric ratio and place them in an agate mortar. Add an appropriate amount of anhydrous ethanol (C2H6O) and grind thoroughly for 15 minutes.

[0045] (2) The mixed raw material powder is placed in a box furnace and calcined at 1150°C for 6 hours in an air atmosphere. The powder is then naturally cooled to room temperature and ground evenly to obtain the tunable dual-mode luminescent phosphor.

[0046] In this embodiment, the tunable dual-mode luminescent phosphor emits orange-yellow light at around 580nm under 322nm ultraviolet light excitation, as shown in Figure 2; its color coordinates are (0.4551, 0.4867), as shown in Figure 3; the afterglow time is shorter than that of Examples 2 to 6, as shown in Figure 4.

[0047] Example 2

[0048] This embodiment provides a tunable dual-mode luminescent phosphor, the chemical formula of which is LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , where x = 0.1 and y = 0.002.

[0049] The preparation method of the tunable dual-mode luminescent phosphor includes the following steps:

[0050] (1) Weigh lithium carbonate (Li2CO3), indium oxide (In2O3), scandium oxide (Sc2O3), germanium dioxide (GeO2), and bismuth trioxide (Bi2O3) according to the stoichiometric ratio and place them in an agate mortar. Add an appropriate amount of anhydrous ethanol (C2H6O) and grind thoroughly for 15 minutes.

[0051] (2) The mixed raw material powder is placed in a box furnace and calcined at 1150°C for 6 hours in an air atmosphere. The powder is then naturally cooled to room temperature and ground evenly to obtain the tunable dual-mode luminescent phosphor.

[0052] In this embodiment, the tunable dual-mode luminescent phosphor emits yellow light at around 550nm under 322nm ultraviolet light excitation, as shown in Figure 2; its color coordinates are (0.3883, 0.4844), as shown in Figure 3; the afterglow time is longer than that of Example 1, and shorter than that of Examples 3 to 6, as shown in Figure 4.

[0053] Example 3

[0054] This embodiment provides a tunable dual-mode luminescent phosphor, the chemical formula of which is LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , where x = 0.2 and y = 0.002.

[0055] The preparation method of the tunable dual-mode luminescent phosphor includes the following steps:

[0056] (1) Weigh lithium carbonate (Li2CO3), indium oxide (In2O3), scandium oxide (Sc2O3), germanium dioxide (GeO2), and bismuth trioxide (Bi2O3) according to the stoichiometric ratio and place them in an agate mortar. Add an appropriate amount of anhydrous ethanol (C2H6O) and grind thoroughly for 15 minutes.

[0057] (2) The mixed raw material powder is placed in a box furnace and calcined at 1150°C for 6 hours in an air atmosphere. The powder is then naturally cooled to room temperature and ground evenly to obtain the tunable dual-mode luminescent phosphor.

[0058] In this embodiment, the tunable dual-mode luminescent phosphor emits cyan light at around 535nm under 319nm ultraviolet light excitation, as shown in Figure 2; its color coordinates are (0.3512, 0.4641), as shown in Figure 3; the afterglow time is longer than that of Embodiments 1 and 2, and shorter than that of Embodiments 4 to 6, as shown in Figure 4.

[0059] Example 4

[0060] This embodiment provides a tunable dual-mode luminescent phosphor, the chemical formula of which is LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , where x = 0.3 and y = 0.002.

[0061] The preparation method of the tunable dual-mode luminescent phosphor includes the following steps:

[0062] (1) Weigh lithium carbonate (Li2CO3), indium oxide (In2O3), scandium oxide (Sc2O3), germanium dioxide (GeO2), and bismuth trioxide (Bi2O3) according to the stoichiometric ratio and place them in an agate mortar. Add an appropriate amount of anhydrous ethanol (C2H6O) and grind thoroughly for 15 minutes.

[0063] (2) The mixed raw material powder is placed in a box furnace and calcined at 1150°C for 6 hours in an air atmosphere. The powder is then naturally cooled to room temperature and ground evenly to obtain the tunable dual-mode luminescent phosphor.

[0064] In this embodiment, the tunable dual-mode luminescent phosphor emits cyan-blue light at around 515nm under 318nm ultraviolet light excitation, as shown in Figure 2; its color coordinates are (0.3016, 0.4230), as shown in Figure 3; the afterglow time is longer than that of Examples 1 to 3, and shorter than that of Examples 5 and 6, as shown in Figure 4.

[0065] Example 5

[0066] This embodiment provides a tunable dual-mode luminescent phosphor, the chemical formula of which is LiIn.1-x-y+xy Sc x-xy GeO4:yBi 3+ , where x = 0.4 and y = 0.002.

[0067] The preparation method of the tunable dual-mode luminescent phosphor includes the following steps:

[0068] (1) Weigh lithium carbonate (Li2CO3), indium oxide (In2O3), scandium oxide (Sc2O3), germanium dioxide (GeO2), and bismuth trioxide (Bi2O3) according to the stoichiometric ratio and place them in an agate mortar. Add an appropriate amount of anhydrous ethanol (C2H6O) and grind thoroughly for 15 minutes.

[0069] (2) The mixed raw material powder is placed in a box furnace and calcined at 1150°C for 6 hours in an air atmosphere. The powder is then naturally cooled to room temperature and ground evenly to obtain the tunable dual-mode luminescent phosphor.

[0070] In this embodiment, the tunable dual-mode luminescent phosphor emits cyan-blue light at around 497nm under 317nm ultraviolet light excitation, as shown in Figure 2; its color coordinates are (0.2527, 0.3551), as shown in Figure 3; the afterglow time is longer than that of Examples 1 to 4, and shorter than that of Example 6, as shown in Figure 4.

[0071] Example 6

[0072] This embodiment provides a tunable dual-mode luminescent phosphor, the chemical formula of which is LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , where x = 0.5 and y = 0.002.

[0073] The preparation method of the tunable dual-mode luminescent phosphor includes the following steps:

[0074] (1) Weigh lithium carbonate (Li2CO3), indium oxide (In2O3), scandium oxide (Sc2O3), germanium dioxide (GeO2), and bismuth trioxide (Bi2O3) according to the stoichiometric ratio and place them in an agate mortar. Add an appropriate amount of anhydrous ethanol (C2H6O) and grind thoroughly for 15 minutes.

[0075] (2) The mixed raw material powder is placed in a box furnace and calcined at 1150°C for 6 hours in an air atmosphere. The powder is then naturally cooled to room temperature and ground evenly to obtain the tunable dual-mode luminescent phosphor.

[0076] In this embodiment, the tunable dual-mode luminescent phosphor emits blue light at around 484nm under 316nm ultraviolet light excitation, as shown in Figure 2; its color coordinates are (0.2360, 0.3197), as shown in Figure 3; the afterglow time is longer than that of Examples 1 to 5, as shown in Figure 4.

[0077] Table 1

[0078]

[0079]

[0080] Application Example 1

[0081] This application example provides an anti-counterfeiting application of tunable dual-mode luminescent phosphor. Tunable dual-mode luminescent phosphors provided in Examples 1, 3, and 6 are selected and placed into molds engraved with the letters G, I, and A, respectively. After excitation with 302nm ultraviolet light for one minute, the excitation source is turned off, and photos are taken simultaneously using a digital camera at 0.1s intervals. As shown in Figure 5, Examples 1 (G), 3 (I), and 6 (A) appear grayish-white under sunlight. When irradiated with 302nm ultraviolet light, Example 1 (G) appears orange-yellow, Example 3 (I) appears cyan, and Example 6 (A) appears blue. This achievement of different colors of luminescence under the same excitation conditions is achieved by adjusting the atomic ratio of In and Sc in the phosphor matrix. After the excitation source is turned off, Example 1 (G) loses its luminescence immediately due to its extremely short afterglow time. Example 3 (I) has an afterglow time longer than Example 1 (G) but shorter than Example 6 (A), and the afterglow phenomenon lasts for approximately 0.2s after the excitation source is turned off. Example 6(A) exhibits the longest afterglow time among the three, maintaining a certain level of luminescence even 0.4 seconds after the excitation source is turned off. This difference in afterglow time after the excitation source is turned off is achieved by adjusting the atomic ratio of In and Sc in the phosphor matrix. Therefore, the phosphor described in this invention possesses both steady-state adjustable luminescence color and dynamic adjustable afterglow time, making it suitable for high-security anti-counterfeiting applications.

[0082] In summary, the tunable dual-mode luminescent phosphor provided by this invention has high stability and will not deliquesce even after being placed in air for a long time. Under ultraviolet light excitation, by adjusting the atomic ratio of Sc to In in the phosphor components, the emission color can be continuously adjusted from orange-yellow light to blue light. At the same time, the afterglow emission time is adjustable, and a visible afterglow time of 0-10s can be maintained after excitation stops.

[0083] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A tunable dual-mode luminescent phosphor, characterized in that, The tunable dual-mode luminescent phosphor has the chemical formula LiIn. 1-x-y+xy Sc x-xy GeO4:yBi 3+ , of which 0 <x≤0.5,0.002≤y≤0.02。 2. The tunable dual-mode luminescent phosphor according to claim 1, characterized in that, The excitation wavelength of the tunable dual-mode luminescent phosphor is 240nm-322nm.

3. The tunable dual-mode luminescent phosphor according to claim 1, characterized in that, The tunable dual-mode luminescent phosphor emits light at wavelengths of 484nm-580nm.

4. The tunable dual-mode luminescent phosphor according to claim 1, characterized in that, The afterglow emission time of the tunable dual-mode luminescent phosphor is 0-10s.

5. A method for preparing a tunable dual-mode luminescent phosphor as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: mixing raw materials Li source, In source, Sc source, Ge source and Bi source, and then calcining them.

6. The preparation method according to claim 5, characterized in that, The Li source includes lithium carbonate.

7. The preparation method according to claim 5, characterized in that, The In source includes indium oxide.

8. The preparation method according to claim 5, characterized in that, The Sc source includes scandium oxide.

9. The preparation method according to claim 5, characterized in that, The Ge source includes germanium dioxide.

10. The preparation method according to claim 5, characterized in that, The Bi source includes bismuth trioxide.

11. The preparation method according to claim 5, characterized in that, The mixing method includes: mixing and grinding the raw materials with anhydrous ethanol.

12. The preparation method according to claim 5, characterized in that, The roasting temperature is 1100-1200℃.

13. The preparation method according to claim 5, characterized in that, The roasting time is 4-8 hours.

14. The preparation method according to claim 5, characterized in that, After roasting, the material is cooled and ground.

15. An application of the tunable dual-mode luminescent phosphor as described in any one of claims 1-4, characterized in that, The tunable dual-mode luminescent phosphor is used for optical anti-counterfeiting.

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