Ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with simultaneously adjustable fluorescence and afterglow and application thereof

Abstract

The invention provides an ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with simultaneously adjustable fluorescence and afterglow and application thereof, the fluorescent anti-counterfeiting material contains ZnS: aKA, bCaB2, yMn < 2 + > and zR < n + >, A is selected from at least one of Cl, Br and I, B is selected from at least one of Cl, Br and I, R < n + > is selected from at least one of Cu < 2 + >, Ag < + >, Er < 3 + >, Sm < 3 + >, Tm < 3 + > and Tb < 3 + >, 0 < = a < = 0.1, 0 < = b < = 0.1, 0 < = y < = 0.004, 0 < z < = 0.001, and a and b are not 0 at the same time. The fluorescent anti-counterfeiting material prepared by the invention has the characteristics of variable fluorescence, variable afterglow and ultra-long afterglow delay, presents fluorescence (one or more of blue light and orange light) with different colors under excitation of different ultraviolet lights (between 254 and 365 nm), and presents afterglow (one or more of green light and orange light) with different colors after excitation is stopped. The fluorescent color of the same fluorescent powder is different from the afterglow color, the afterglow delay is larger than 5 s, and the fluorescent powder can be applied to industrial anti-counterfeiting application.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic materials, and in particular to an ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow, and application thereof. Background Art

[0002] Vigorously developing anti-counterfeiting technology has become an important measure to ensure national public security, economic order, and the rights and interests of producers and consumers from the source.

[0003] Compared with other anti-counterfeiting technologies (such as laser holography, QR code, etc.), ink anti-counterfeiting technology has the advantages of easy implementation, intuitive identification, significant anti-counterfeiting effect, wide application range, and low cost of technology iteration. Therefore, it has become the dominant technology in the anti-counterfeiting industry. The fluorescent materials added to fluorescent anti-counterfeiting inks are usually invisible (invisible) or appear in a certain color under natural light, but they will emit different fluorescence under specific excitation sources (such as light, deformation, thermal change, magnetic field), and the color, brightness and duration of the fluorescence can be designed as needed, which can give the ink a variety of anti-counterfeiting effects. Currently, the fluorescent anti-counterfeiting inks on the market mainly emit fixed colors under fixed excitation, have low anti-counterfeiting performance, and are easy to be forged. Therefore, the development of dynamic fluorescent anti-counterfeiting materials with multi-dimensional response can greatly promote the development of the anti-counterfeiting industry.

[0004] The zinc sulfide matrix doped with rare earth ions or transition metal ions belongs to the category of inorganic materials, which has the advantages of low biological toxicity, rich emission bands, good stability, cheap and easy to obtain materials, and easy large-scale production. However, most of the zinc sulfide luminescent materials reported so far are single-mode monochromatic luminescence or multi-mode monochromatic luminescence, such as doping additives (NaCl, NaBr, etc.) or Ag. + Then blue light emission is realized; doped with Mn 2+ Achieve yellow light emission, doped with Cu 2+ After that, green light emission is achieved with green afterglow. In addition, there is also a case report that the additive and Mn 2+ Doping achieves multi-mode and multi-color luminescence with simultaneous response of wavelength and time. However, the afterglow has a single color and a very short afterglow time (<5 s), which makes it difficult to popularize and apply. Therefore, it is urgent to develop new anti-counterfeiting materials with variable fluorescence, variable afterglow, and long afterglow time. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide an ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow and its application.

[0006] The technical solution adopted by the present invention is as follows: The first aspect of the present invention provides an ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow at the same time, wherein the fluorescent anti-counterfeiting material contains ZnS:a K A, b CaB2, y Mn 2+ , z R n+ , Wherein, A is selected from at least one of Cl, Br, and I, B is selected from at least one of Cl, Br, and I, and R n+ Selected from Cu 2+ 、Ag + , Er 3+ 、Sm 3+ 、Tm 3+ , Tb 3+ At least one of 0≤a≤0.1, 0≤b≤0.1, 0<y≤0.004, 0< z ≤0.001, a and b are not 0 at the same time.

[0007] Preferably, 0<a≤0.1, 0<b≤0.1.

[0008] Preferably, the preparation method comprises the following steps: S1. Mix KA solution, CaB2 solution, ZnS and Mn salt in proportion and dry at 60-100℃. After drying, add R n+ The corresponding oxides and / or carbonates are ground uniformly to obtain a precursor powder; S2. Place the precursor powder in a box furnace, heat it to 750-1100℃ and calcine it for 2-4 hours. Grind it evenly after cooling it to room temperature.

[0009] Preferably, in step S2, the heating rate is 2-12°C / min.

[0010] Preferably, in step S2, the temperature is increased, calcined and cooled in a CO atmosphere.

[0011] Preferably, the CO atmosphere is provided by carbon powder.

[0012] The second aspect of the present invention provides the use of the ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow as described above in the preparation of anti-counterfeiting products.

[0013] The beneficial effects of the present invention are as follows: ZnS prepared by the present invention: x MX, y Mn 2+ / z R n+Zinc sulfide fluorescent anti-counterfeiting materials have the characteristics of variable fluorescence, variable afterglow, and ultra-long afterglow delay. They show different colors of fluorescence (one or more of blue light and orange light) under different ultraviolet light excitation (between 254-365 nm), and different colors of afterglow (one or more of green light and orange light) after the excitation stops. The fluorescence color of the same phosphor is different from the afterglow color, and the afterglow delay is greater than 5 s, which can be used in industrial anti-counterfeiting applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0015] Figure 1 (a) fluorescence spectrum, (b) afterglow spectrum, (c) CIE coordinate diagram, and (d) afterglow decay spectrum of the phosphor prepared in Example 1; Figure 2 (a) fluorescence spectrum and afterglow spectrum, (b) afterglow decay spectrum, and (c) CIE coordinate diagram of the phosphor prepared in Example 2; Figure 3 (a) fluorescence spectrum and afterglow spectrum, (b) afterglow decay spectrum, and (c) CIE coordinate diagram of the phosphor prepared in Example 3; Figure 4 (a) fluorescence spectrum and afterglow spectrum, (b) afterglow decay spectrum, and (c) CIE coordinate diagram of the phosphor prepared in Example 4; Figure 5 (a) fluorescence spectrum, (b) phosphorescence spectrum, and (c) afterglow decay spectrum of the phosphor prepared in Example 5; Figure 6 (a) fluorescence spectrum and (b) afterglow decay spectrum of the phosphor prepared in Example 6; Figure 7 (a) Phosphorescence spectrum and (b) Afterglow decay spectrum of the phosphor prepared in Example 7; Figure 8 The afterglow decay spectra of the phosphors prepared in Comparative Example 1 (a) and Example 2 (b) are shown. DETAILED DESCRIPTION

[0016] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0017] Example 1 This example synthesizes a ZnS:0.04KBr,0.0015Mn 2+ ,0.0005Cu 2+ The material is prepared as follows: S1. Weigh 9.7460 g ZnS, 0.4760 g KBr, 0.0172 g MnCO3, and 0.0012 g CuSO4·5H2O. Place the weighed KBr in an evaporating dish, add appropriate amount of distilled water to dissolve it, add weighed ZnS and MnCO3 powders, and place in an oven at 80°C until dried.

[0018] S2. Transfer the dried powder to a mortar, add weighed CuSO4·5H2O and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and heat it to 900 ℃ for reaction for 2.5 h. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0019] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃→900℃, 25min; The fourth stage: 900℃, 150min (holding time); Stage 5: 900℃→800℃, 25min; Stage 6: The program stops and the temperature drops naturally.

[0020] The multicolor phosphor prepared in Example 1 exhibits green and yellow-green colors under 302 nm and 365 nm ultraviolet light, respectively, and the color coordinates are (0.274, 0.401) and (0.319 and 0.437), respectively. The fluorescence spectrum (normalized) and color coordinates are as follows: Figure 1 (a) and Figure 1 After removing the excitation, the afterglow color is different from its corresponding excitation color. At the same time, the afterglow color under different excitations is also different. After fading excitation at 302 nm and 365 nm, it appears yellow and yellow-green, respectively, with color coordinates of (0.352, 0.473) and (0.346 and 0.500), respectively. The afterglow spectrum (normalized) and color coordinates are shown in Figure 1 (b) and Figure 1 (c) The afterglow decay time also reaches more than 20 s, as shown in Figure 1 (d) shown.

[0021] Example 2 This example synthesizes a ZnS: 0.04KCl, 0.0015Mn 2+ ,0.0001Ag + , and its preparation method is as follows: S1. Weigh 9.7460 g ZnS, 0.2980 g KCl, 0.0172 g MnCO3, and 0.0016 g AgNO3. Place the weighed KCl in an evaporating dish, add appropriate amount of distilled water to dissolve it, and add the weighed ZnS and MnCO3 powders. Place in an oven at 80°C until dried.

[0022] S2. Transfer the dried powder to a mortar, add weighed AgNO3 and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and heat it to 800 ℃ for reaction for 2.5 hours. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0023] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃, 150min (holding time); Stage 4: The program stops and the temperature drops naturally.

[0024] The fluorescent powder prepared in Example 2 exhibits pink and pink colors under 302 nm and 365 nm ultraviolet light, respectively, and the color coordinates are (0.311, 0.232) and (0.376 and 0.296), respectively. After removing the excitation, the afterglow color displayed is different from its corresponding excitation color. After fading the excitation at 365 nm, it exhibits orange-yellow color with color coordinates of (0.467, 0.389). Its fluorescence spectrum (normalized), afterglow spectrum (normalized) and color coordinates are as follows: Figure 2 (a) and Figure 2 (c) The afterglow decay time reaches more than 5 s. Figure 2 (b) shown.

[0025] Example 3 This example synthesizes a ZnS:0.04CaBr2,0.0015Mn 2+ ,0.0003Tm 3+ The material is prepared as follows: S1. Weigh 9.7460 g ZnS, 0.0172 g MnCO3, 0.0116 g Tm2O3, and prepare 0.5 mol / L CaBr2 standard solution. Weigh 8 mL CaBr2 standard solution into an evaporating dish, add weighed ZnS and MnCO3 powders, and place in an oven at 80°C until dry.

[0026] S2. Transfer the dried powder to a mortar, add weighed Tm2O3 and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and raise it to 850 ℃ for reaction for 2.5 hours. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0027] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃→850℃, 12.5min; The fourth stage: 850℃, 150min (holding time); Stage 5: 850°C → 800°C, 12.5 min; Stage 6: The program stops and the temperature drops naturally.

[0028] The multicolor phosphor prepared in Example 3 exhibits white and yellow colors under 302 nm and 365 nm ultraviolet light, respectively, with color coordinates of (0.308, 0.278) and (0.501 and 0.411), respectively. After removing the excitation, the afterglow color displayed is different from its corresponding excitation color. The 365 nm de-excitation shows orange-yellow color with color coordinates of (0.549, 0.434). Its fluorescence spectrum (normalized), afterglow spectrum (normalized) and color coordinates are as follows: Figure 3 (a) and Figure 3 (c) The afterglow decay time also reaches more than 5 s, as shown in Figure 3 (b) shown.

[0029] Example 4 This example synthesizes a ZnS:0.04KBr,0.001Mn 2+ ,0.0001Er 3+ The material is prepared as follows: S1. Weigh 9.7460 g ZnS, 0.4760 g KBr, 0.0115 g MnCO3, and 0.0038 g Er2O3. Place the weighed KBr in an evaporating dish, add appropriate amount of distilled water to dissolve it, and add weighed ZnS and MnCO3 powders. Place in an oven at 80°C until dried.

[0030] S2. Transfer the dried powder to a mortar, add weighed Er2O3 and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and heat it to 1100 ℃ for reaction for 2 h. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0031] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃→1000℃, 50min; Stage 4: 1000℃→1100℃, 35min; The fourth stage: 1100℃, 120min (holding time); Stage 5: 1100℃→1000℃, 35min; Stage 6: 1000℃→800℃, 50min; Stage 7: The program stops and the temperature drops naturally.

[0032] The multicolor phosphor prepared in Example 4 exhibits green and yellow-green colors under 302 nm and 365 nm ultraviolet light, respectively, with color coordinates of (0.291, 0.366) and (0.329 and 0.401), respectively. After removing the excitation, the afterglow color displayed is different from its corresponding excitation color. The 365 nm de-excitation shows yellow with color coordinates of (0.354, 0.490). Its fluorescence spectrum, afterglow spectrum and color coordinates are shown in Figure 4 (a) and Figure 4 (c) The afterglow decay time also reaches more than 30 s, as shown in Figure 4 (b) shown.

[0033] Example 5 This example synthesizes a ZnS: 0.02KBr, 0.02CaBr2, 0.002Mn 2+ ,0.0003Sm 3+ The material is prepared as follows: S1. Weigh 9.7460 g ZnS, 0.2380 g KBr, 0.0230 g MnCO3, and 0.0105 g Sm2O3. Place the weighed KBr in an evaporating dish, add an appropriate amount of distilled water to dissolve it, and prepare a 0.5 mol / L CaBr2 standard solution. Weigh 4 mL of the CaBr2 standard solution in an evaporating dish, add the weighed ZnS and MnCO3 powders, and place in an oven at 80°C until dried.

[0034] S2. Transfer the dried powder to a mortar, add weighed Sm2O3 and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and raise it to 850 ℃ for reaction for 2.5 hours. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0035] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃→850℃, 12.5min; The fourth stage: 850℃, 150min (holding time); Stage 5: 850°C → 800°C, 12.5 min; Stage 6: The program stops and the temperature drops naturally.

[0036] KBr can be doped into the ZnS lattice to produce substitution defects and enhance cyan emission. CaBr2 is mainly used as a cosolvent to accelerate the reaction process and adjust the concentration of the two phases, thereby enhancing cyan emission. Therefore, Figure 5 As shown, the synergistic effect of KBr and CaBr2 can further enhance the luminous intensity, afterglow intensity and afterglow decay time of the phosphor.

[0037] Example 6 This example synthesizes a ZnS: 0.02KBr, 0.02CaBr2, 0.0015Mn 2+ ,0.0001Cu 2+ , 0.0001Ag + The material is prepared as follows: S1. Weigh 9.7460 g ZnS, 0.2380 g KBr, 0.0172 g MnCO3, 0.0025 g CuSO4·5H2O, and 0.0017 g AgNO3. Place the weighed KBr in an evaporating dish, add appropriate amount of distilled water to dissolve it, and prepare 0.5 mol / L CaBr2 standard solution. Weigh 4 mL CaBr2 standard solution in an evaporating dish, add weighed ZnS and MnCO3 powders, and place in an oven at 80°C until dried.

[0038] S2. Transfer the dried powder to a mortar, add weighed MnCO3 and AgNO3 and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and raise it to 850 ℃ for reaction for 2.5 h. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0039] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃→850℃, 12.5min; The fourth stage: 850℃, 150min (holding time); Stage 5: 850°C → 800°C, 12.5 min; Stage 6: The program stops and the temperature drops naturally.

[0040] like Figure 6 As shown, Ag + It can significantly improve the luminous intensity and afterglow time of the phosphor.

[0041] Example 7 This example synthesizes a ZnS: 0.02KBr, 0.02CaBr2, 0.0015Mn 2+ ,0.0001 Ag + ,0.0001Er 3+ The material is prepared as follows: S1. Weigh 9.7460 g ZnS, 0.2380 g KBr, 0.0172 g MnCO3, 0.0017 g AgNO3, and 0.0038 g Er2O3. Place the weighed KBr in an evaporating dish, add appropriate amount of distilled water to dissolve it, and prepare 0.5 mol / L CaBr2 standard solution. Weigh 4 mL CaBr2 standard solution in an evaporating dish, add weighed ZnS and MnCO3 powders, and place in an oven at 80°C until dried.

[0042] S2. Transfer the dried powder to a mortar, add weighed Er2O3 and AgNO3 and grind thoroughly for about 30 min. After mixing evenly, put it into a corundum crucible and place it in a sagger with carbon powder pressed at the bottom. Send it into a high-temperature box furnace and raise it to 850 ℃ for reaction for 2.5 h. After cooling to room temperature with the furnace, grind it evenly to obtain the target phosphor.

[0043] The high temperature box furnace in step S2 specifically uses the following procedure to control the temperature inside the furnace: The first stage: 40℃→500℃, 100min; The second stage: 500℃→800℃, 30min; The third stage: 800℃→850℃, 12.5min; The fourth stage: 850℃, 150min (holding time); Stage 5: 850°C → 800°C, 12.5 min; Stage 6: The program stops and the temperature drops naturally.

[0044] like Figure 7 As shown, Er 3+ After that, the phosphorescence intensity and afterglow time of the phosphor can be significantly improved.

[0045] Comparative Example 1 This comparative example synthesizes a ZnS:0.04KBr,0.0015Mn 2+ ,0.0005Cu 2+ The material, the preparation method thereof is different from that of Example 2 only in that: in step S2, after the temperature of the high-temperature box furnace rises to 800°C, the box door is opened and the sagger is placed in the high-temperature box furnace to react for 2.5 hours. After the reaction is completed, the box door is opened and the sagger is taken out and cooled at room temperature to obtain the phosphor.

[0046] like Figure 8 (a) and (b) show the comparison of the afterglow decay time of the phosphors prepared in comparative example 1 and example 2, respectively. The phosphors prepared by the slow-in (furnace) and slow-out (furnace) high-temperature solid-phase method of the embodiment of the present invention can effectively increase the afterglow time and are suitable for commercial anti-counterfeiting applications.

[0047] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. An ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow, characterized in that: The fluorescent anti-counterfeiting material contains ZnS: a K A, b CaB2, y Mn 2+ , z R n+ , Wherein, A is selected from at least one of Cl, Br, and I, B is selected from at least one of Cl, Br, and I, and R n+ Selected from Cu 2+ 、Ag + , Er 3+ 、Sm 3+ 、Tm 3+ , Tb 3+ At least one of 0≤a≤0.1, 0≤b≤0.1, 0<y≤0.004, 0< z ≤0.001, a and b are not 0 at the same time.

2. The ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow according to claim 1, characterized in that: 0<a≤0.1, 0<b≤0.

1.

3. The ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow according to claim 1, characterized in that: The preparation method comprises the following steps: S1. Mix KA solution, CaB2 solution, ZnS and Mn salt in proportion and dry at 60-100℃. After drying, add R n+ The corresponding oxides and / or carbonates are ground uniformly to obtain a precursor powder; S2. Place the precursor powder in a box furnace, heat it to 750-1100℃ and calcine it for 2-4 hours. Grind it evenly after cooling it to room temperature.

4. The ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow according to claim 3, characterized in that: In step S2, the heating rate is 2-12°C / min.

5. The ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow according to claim 3, characterized in that: In step S2, the temperature is increased, calcined, and cooled in a CO atmosphere.

6. The ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow according to claim 3, characterized in that: The CO atmosphere is provided by carbon powder.

7. Use of the ultra-long afterglow zinc sulfide fluorescent anti-counterfeiting material with adjustable fluorescence and afterglow as described in any one of claims 1 to 6 in the preparation of anti-counterfeiting products.

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