Matrix assisted multicolor luminescent material, preparation method and application thereof

Abstract

The application provides a substrate-assisted multicolor luminescent material and a preparation method and application thereof, and the chemical expression is SrS:x%Sm, 0<=x<=1.5; the preparation method comprises the following steps: preparing mixed powder, preparing a reaction device and microwave reaction; the application can be applied to a transparent anti-fake film and used for designing an anti-fake label. The application finds a design of an optical anti-fake indicator of a single rare earth ion doped combination of substrate-assisted luminescence; successfully exhibits color abundance change and fluorescent regulation response properties in a single material, realizes color regulation in a full visible light range, exhibits fluorescent stimulation response properties and excellent color adjustability, emits orange yellow light under low wavelength laser, emits green light under high wavelength laser, and the substrate luminescence intensity is high and visible to the naked eye.

Description

Technical Field

[0001] This invention relates to the field of inorganic luminescent materials technology, specifically to a matrix-assisted multicolor luminescent material, its preparation method, and its application. Background Technology

[0002] Fluorescence-modulated luminescent materials play a crucial role in a variety of potential applications, from white light-emitting diodes (WLEDs), X-ray imaging detectors, emergency lighting, optoelectronic components, anti-counterfeiting, and security information. Typical fluorescence-modulated luminescent materials are based on selecting different phosphors and various rare-earth ions to create different emission wavelengths. This combination is a common method for obtaining color-tunable indicators, and the effective control of fluorescence color depends on the ratio of different rare-earth ion dopants. However, existing doped matrices with good luminescence performance lack readily available synthesis methods and applications. Traditional solid-state synthesis methods are inefficient, and the sintered matrices exhibit weak luminescence intensity and unsatisfactory luminescence effects. Summary of the Invention

[0003] The purpose of this invention is to provide a matrix-assisted multicolor luminescent material, its preparation method, and its application, in order to solve the above-mentioned technical problems.

[0004] This invention provides a matrix-assisted multicolor luminescent material with the chemical formula: SrS:x%Sm; where 0≤x≤1.5.

[0005] This invention also provides a method for preparing a matrix-assisted multicolor luminescent material, comprising the following steps:

[0006] Step (1): Prepare the mixed powder

[0007] SrS, boric acid and Sm2O3 are mixed. SrS and Sm2O3 are mixed in a molar ratio of 1:0 to 1:0.015. The amount of boric acid added is 2 to 4% of the mass of SrS and Sm2O3. Then ethanol is added and the mixture is ground and mixed evenly to obtain a mixed powder.

[0008] Step (II) Preparing the reaction apparatus

[0009] The mixed powder is placed in a raw material storage bottle and then placed in a reactor. The reactor is wrapped with activated carbon powder. The reactor is then placed in the cavity of a heat-resistant brick assembly to obtain a reaction device equipped with the mixed powder.

[0010] Step (3) Microwave reaction

[0011] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 10-30 minutes at a power of 1000 W, cooled for 1 hour, and then ground to obtain matrix-assisted multicolor luminescent material.

[0012] As a further preferred option of the above scheme:

[0013] 3 ml of ethanol is added to every 1 g of raw material; after adding ethanol, the raw material is ground to 150-200 mesh to obtain a mixed powder.

[0014] As a further preferred option of the above scheme:

[0015] The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50; the mass ratio of activated carbon powder to mixed powder is 20:1.

[0016] As a further preferred option of the above scheme:

[0017] The activated carbon powder is laid at the bottom of the reactor, and the amount of activated carbon powder filling the reactor is enough to cover 1 / 2 of the height of the raw material storage bottle.

[0018] As a further preferred option of the above scheme:

[0019] The heat-resistant brick assembly includes a heat-resistant brick cover, a heat-resistant brick body, and a heat-resistant brick bottom arranged from top to bottom, and the heat-resistant brick cover, heat-resistant brick body, and heat-resistant brick bottom surround and form the cavity.

[0020] This invention also provides an application of matrix-assisted multicolor luminescent material, which is applied to a transparent anti-counterfeiting film for the design of anti-counterfeiting labels.

[0021] As a further preferred option of the above scheme:

[0022] The transparent anti-counterfeiting film is prepared by mixing matrix-assisted multicolor luminescent material and PDMS colloid evenly to obtain a mixed gel-like liquid, then placing the mixed gel-like liquid in a mold and heating it at a temperature of 40-50℃ for 6-8 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence multi-stimulus response characteristics.

[0023] As a further preferred option of the above scheme:

[0024] The mass ratio of the matrix-assisted multicolor luminescent material to the PDMS colloid is 1:2.5 to 1:3.5.

[0025] The beneficial effects of this invention are as follows:

[0026] (1) Existing methods for preparing multicolor luminescent materials (e.g., hydrothermal methods) involve low temperatures and long preparation times. However, the preparation method of this invention, a simple direct microwave reaction method, is more design-oriented. This invention uses a solid-state microwave-assisted method, employing activated carbon powder for temperature conduction through the construction of a reaction apparatus. The core temperature can reach over 1000°C within minutes. This invention uses a special atmosphere filling method, eliminating the need for external gas and reducing the risk of synthesis production. By embedding activated carbon powder, a reducing atmosphere is provided, and the core temperature can reach over 1000°C through activated carbon conduction. The activated carbon powder must be placed tightly and flat, minimizing gaps between the powder particles, and adhering to the bottom of the container to prevent the activated carbon powder from flying away and affecting the reaction temperature and uniformity, thus damaging the product performance.

[0027] (2) The reaction device of the present invention includes a heat-resistant brick cover, a heat-resistant brick body, a heat-resistant brick bottom, a raw material storage bottle, a crucible reactor and a microwave oven; the heat-resistant brick, which is made of a mixture of refractory materials such as alumina, aluminum silicate and magnesium silicate, can withstand a high temperature of 1500℃, providing good heat insulation for the reactor, so that the raw material storage bottle can reach a continuous high temperature environment, and the raw materials therein can be fully reacted.

[0028] (3) The reaction environment provided by the reaction device of the present invention is mild and modular, which reduces the traditional reaction time from more than ten hours to tens of minutes, shortening the process time and improving productivity. Furthermore, the raw materials of strontium sulfide, samarium oxide and boric acid required for the reaction of the present invention are easy to obtain and have low cost, which can meet the needs of large-scale industrial production.

[0029] (4) The matrix-assisted multicolor luminescent material prepared by the present invention belongs to the fluorescent luminescent material. By synthesizing a suitable luminescent matrix SrS and doping with a single rare earth ion (samarium ion in the present invention), the matrix SrS, which can effectively emit light, is used to change the limitations of existing multi-rare earth ion doped materials and the complexity of selecting doped matrix from the perspective of color change and fluorescence response. This provides a new solution to the complexity and difficulty in control of multi-rare earth ion doped materials in existing luminescent anti-counterfeiting label materials, which do not have the property of color change in response to fluorescence stimulation.

[0030] (5) The present invention has found a design for an optical anti-counterfeiting indicator with matrix-assisted luminescence and single rare earth ion doping combination; the present invention successfully exhibits color abundance change and fluorescence regulation response properties in a single material, realizes color regulation in the full visible light range, exhibits fluorescence stimulation reactivity and excellent color tunability, emits orange-yellow light under low wavelength laser and green light under high wavelength laser, and has high matrix luminescence intensity that is visible to the naked eye.

[0031] (6) The reaction device of the present invention is placed on the circumference at a distance of 5 cm from the center of the microwave oven reactor, which enables the reaction device to uniformly receive microwaves emitted by the microwave oven transmitter. The location of the center of the microwave oven is difficult to determine as the location of the peak or trough of the microwave emitted by the microwave oven transmitter, but the wavelength received at the center is certain. Placing the heat-resistant brick assembly at a position away from the center can receive different wavelengths, so that the mixed powder can react uniformly. Attached Figure Description

[0032] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0033] Figure 1 This is a schematic diagram of the reaction apparatus in an embodiment of the present invention;

[0034] Figure 2 The X-ray diffraction patterns are of the standard reference material and the materials prepared in Examples 2 and 5-7 of this invention.

[0035] Figure 3 The X-ray diffraction patterns are of the standard reference material and the materials prepared in Examples 1-4 and Comparative Example 1 of this invention.

[0036] Figure 4 These are images showing the emission color and long afterglow phenomenon of the materials prepared in Examples 2 and 5 of this invention under different wavelength excitation light sources;

[0037] Figure 5 This is the optimal excitation and emission spectrum of the material prepared in Example 2 of the present invention;

[0038] Figure 6 These are the emission spectra of the materials prepared in Examples 5-7, Comparative Example 1, and Example 2 of this invention under different wavelength excitation light sources;

[0039] Figure 7 These are the emission spectra of the materials prepared in Examples 1-4 of this invention under different wavelength excitation light sources;

[0040] Figure 8 This is a two-dimensional emission spectrum of the full-range spectrum of the material prepared in Example 2 of this invention;

[0041] Figure 9 This is a long afterglow decay diagram of the material prepared in Example 2 of the present invention;

[0042] Figure 10 This is a SEM image of the material prepared in Example 2 of the present invention;

[0043] The markings in the diagram are: 1. Raw material storage bottle; 2. Reactor; 3. Heat-resistant brick cover; 4. Heat-resistant brick bottom; 5. Heat-resistant brick body. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. The reaction apparatus used in the specific embodiments of the present invention is as follows: Figure 1 As shown, it specifically includes a heat-resistant brick cover 3, a heat-resistant brick body 5, a heat-resistant brick bottom 4, a reactor 2, and a raw material storage bottle 1; the heat-resistant brick body 5 has a heat-resistant brick cover 3 at the upper end and a heat-resistant brick bottom 4 at the lower end, and a cavity in the middle of the heat-resistant brick body 5, in which the reactor 2 is placed; the raw material storage bottle 1 is placed in the reactor 2.

[0045] Example 1

[0046] The matrix-assisted multicolor luminescent material in Example 1 has the chemical formula: SrS:1%Sm; the preparation method includes the following steps:

[0047] Step (1): Prepare the mixed powder

[0048] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0049] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0.01; the amount of boric acid added is 2% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 150 mesh to obtain a mixed powder.

[0050] Step (II) Preparing the reaction apparatus

[0051] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by activated carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0052] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0053] Step (3) Microwave reaction

[0054] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 10 min at a power of 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:1%Sm.

[0055] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0056] This embodiment 1 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in the design of transparent anti-counterfeiting films for anti-counterfeiting labels. The preparation method of the transparent anti-counterfeiting film is as follows: the SrS:1%Sm fluorescent material prepared above is mixed uniformly with PDMS colloid to obtain a mixed gel-like liquid. The mixed gel-like liquid is then placed in a mold and heated at 40°C for 8 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence and multi-stimulus response characteristics.

[0057] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:1%Sm to PDMS colloid is 1:2.5.

[0058] Example 2

[0059] The matrix-assisted multicolor luminescent material in Example 2 has the chemical formula: SrS:1%Sm; the preparation method includes the following steps:

[0060] Step (1): Prepare the mixed powder

[0061] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0062] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0.01; the amount of boric acid added is 3% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 170 mesh to obtain a mixed powder.

[0063] Step (II) Preparing the reaction apparatus

[0064] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0065] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0066] Step (3) Microwave reaction

[0067] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 15 min at a power of 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:1%Sm.

[0068] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0069] This embodiment 2 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in a transparent anti-counterfeiting film for designing anti-counterfeiting labels. The preparation method of the transparent anti-counterfeiting film is as follows: the SrS:1%Sm fluorescent material prepared above is mixed evenly with PDMS colloid to obtain a mixed gel-like liquid, and then the mixed gel-like liquid is placed in a mold and heated at 50°C for 7 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence multi-stimulus response characteristics.

[0070] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:1%Sm to PDMS colloid is 1:3.

[0071] Example 3

[0072] The matrix-assisted multicolor luminescent material in Example 3 has the chemical formula: SrS:1%Sm; the preparation method includes the following steps:

[0073] Step (1): Prepare the mixed powder

[0074] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0075] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0.01; the amount of boric acid added is 3% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 150 mesh to obtain a mixed powder.

[0076] Step (II) Preparing the reaction apparatus

[0077] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0078] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0079] Step (3) Microwave reaction

[0080] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 20 min at a power of 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:1%Sm.

[0081] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0082] This embodiment 3 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in the design of transparent anti-counterfeiting films for anti-counterfeiting labels. The transparent anti-counterfeiting film is prepared by uniformly mixing the aforementioned SrS:1%Sm fluorescent material with PDMS colloid to obtain a mixed gel-like liquid. The mixed gel-like liquid is then placed in a mold and heated at 50°C for 7 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence and multi-stimulus response characteristics.

[0083] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:1%Sm to PDMS colloid is 1:3.

[0084] Example 4

[0085] The matrix-assisted multicolor luminescent material in Example 4 has the chemical formula: SrS:1%Sm; the preparation method includes the following steps:

[0086] Step (1): Prepare the mixed powder

[0087] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0088] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0.01; the amount of boric acid added is 4% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 200 mesh to obtain a mixed powder.

[0089] Step (II) Preparing the reaction apparatus

[0090] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0091] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0092] Step (3) Microwave reaction

[0093] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 30 min at a power of 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:1%Sm.

[0094] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0095] This embodiment 4 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in the design of transparent anti-counterfeiting films for anti-counterfeiting labels. The transparent anti-counterfeiting film is prepared by uniformly mixing the aforementioned SrS:1%Sm fluorescent material with PDMS colloid to obtain a mixed gel-like liquid. The mixed gel-like liquid is then placed in a mold and heated at 40°C for 6 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence and multi-stimulus response characteristics.

[0096] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:1%Sm to PDMS colloid is 1:3.5.

[0097] Example 5

[0098] The matrix-assisted multicolor luminescent material in Example 5 has the chemical formula: SrS:0%Sm; the preparation method includes the following steps:

[0099] Step (1): Prepare the mixed powder

[0100] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0101] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0; the amount of boric acid added is 3% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 170 mesh to obtain a mixed powder.

[0102] Step (II) Preparing the reaction apparatus

[0103] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0104] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0105] Step (3) Microwave reaction

[0106] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 15 min at a power of 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:0%Sm.

[0107] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0108] This embodiment 5 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in the design of transparent anti-counterfeiting films for anti-counterfeiting labels. The transparent anti-counterfeiting film is prepared by uniformly mixing the aforementioned SrS:0%Sm fluorescent material with PDMS colloid to obtain a mixed gel-like liquid. The mixed gel-like liquid is then placed in a mold and heated at 50°C for 7 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence and multi-stimulus response characteristics.

[0109] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:0%Sm to PDMS colloid is 1:3.

[0110] Example 6

[0111] The matrix-assisted multicolor luminescent material in Example 6 has the chemical formula: SrS:0.5%Sm; the preparation method includes the following steps:

[0112] Step (1): Prepare the mixed powder

[0113] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0114] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0.005; the amount of boric acid added is 3% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 170 mesh to obtain a mixed powder.

[0115] Step (II) Preparing the reaction apparatus

[0116] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0117] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0118] Step (3) Microwave reaction

[0119] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 15 min at 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:0.5%Sm.

[0120] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0121] This embodiment 6 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in the design of a transparent anti-counterfeiting film for anti-counterfeiting labels. The transparent anti-counterfeiting film is prepared by uniformly mixing the aforementioned SrS:0.5%Sm fluorescent material with PDMS colloid to obtain a mixed gel-like liquid. The mixed gel-like liquid is then placed in a mold and heated at 50°C for 7 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence and multi-stimulus response characteristics.

[0122] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:0.5%Sm to PDMS colloid is 1:3.

[0123] Example 7

[0124] The matrix-assisted multicolor luminescent material in Example 7 has the chemical formula: SrS:1.5%Sm; the preparation method includes the following steps:

[0125] Step (1): Prepare the mixed powder

[0126] SrS, boric acid and Sm2O3 are mixed, ethanol is added and the mixture is ground until homogeneous to obtain a mixed powder.

[0127] Specifically: SrS and Sm2O3 are mixed in a molar ratio of 1:0.015; the amount of boric acid added is 3% of the mixed mass of SrS and Sm2O3; during the addition of ethanol, 3 ml of ethanol is added for every 1 g of raw material; after adding ethanol, the raw material is ground to 170 mesh to obtain a mixed powder.

[0128] Step (II) Preparing the reaction apparatus

[0129] (1) Place the mixed powder into the raw material storage bottle 1 and compact it to minimize the voids. Cover the raw material storage bottle 1 with the cap to isolate the mixed powder from the external environment and prevent it from being contaminated by carbon powder. Place the raw material storage bottle in the reactor 2. The reactor 2 is wrapped with a layer of activated carbon powder to provide a reducing atmosphere. The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50. The mass ratio of the activated carbon powder to the mixed powder is 20:1. The activated carbon powder is laid at the bottom of the reactor 2. When laying it, it is compacted and flat. The filled activated carbon powder can cover 1 / 2 of the height of the raw material storage bottle 1, which is convenient to take out and can prevent the sample from being contaminated by activated carbon powder.

[0130] (2) Place reactor 2 in the center of heat-resistant brick base 4, place heat-resistant brick body 5 on the outside of reactor 2, and place heat-resistant brick cover 3 to make reactor 2 have a good heat insulation environment and minimize heat loss; thus obtaining a reaction device equipped with mixed powder.

[0131] Step (3) Microwave reaction

[0132] The reaction apparatus containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 15 min at 1000 W, cooled for 1 h, and then ground to obtain matrix-assisted multicolor luminescent material SrS:1.5%Sm.

[0133] After the microwave reaction, the sample was allowed to cool naturally for 1 hour. The reaction vessel was then cleaned with ethanol to prevent contamination that could impair the luminescence intensity. The apparatus was then opened to retrieve the matrix-assisted multicolor luminescent material.

[0134] This embodiment 7 also provides an application of the aforementioned matrix-assisted multicolor luminescent material, which is used in the design of a transparent anti-counterfeiting film for anti-counterfeiting labels. The transparent anti-counterfeiting film is prepared by uniformly mixing the aforementioned SrS:1%Sm fluorescent material with PDMS colloid to obtain a mixed gel-like liquid. The mixed gel-like liquid is then placed in a mold and heated at 40°C for 6 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence and multi-stimulus response characteristics.

[0135] In addition, the mass ratio of matrix-assisted multicolor luminescent material SrS:1.5%Sm to PDMS colloid is 1:3.

[0136] Comparative Example 1

[0137] This comparative example uses existing techniques to prepare the multicolor luminescent material of the present invention, including the following steps:

[0138] Step (1): Prepare the mixed powder

[0139] SrS, boric acid, and Sm2O3 were added to a small amount of ethanol and ground and mixed to obtain a uniform powder. SrS and Sm2O3 were mixed at a molar ratio of 1:0.01. The amount of boric acid added was 2% of the mixed mass of strontium sulfide and samarium oxide. During the addition of ethanol, 3 ml of ethanol was added for every 1 g of raw material. After adding ethanol, the raw material was ground to 150 mesh to obtain a mixed powder.

[0140] Step (II) Solid-phase reaction

[0141] Place the mixed powder from step (I) into a corundum crucible; place the corundum crucible in the middle of a high-temperature solid-state furnace tube, and then introduce hydrogen gas as a reducing gas to provide a reducing atmosphere for the sample experiment; react in a high-temperature solid-state method, anneal at 1363K for 2 hours, cool for 1 hour, and grind to obtain SrS:1%Sm matrix-assisted multicolor luminescent material.

[0142] Comparative analysis:

[0143] The XRD standard diffraction card PDF#01-071-3683 for SrS was used as a reference to verify the synthesis of SrS:x%Sm (0≤x≤1.5) under the same conditions.

[0144] The microwave-assisted long-afterglow luminescent materials obtained in Examples 1-7 and Comparative Example 1 were tested and analyzed using an X-ray diffractometer. The results are as follows: Figure 2 and Figure 3 As shown in the figure, the XRD data of the SrS matrix prepared by microwave reaction (i.e., when x = 0) and the SrS:x%Sm (0 < x ≤ 1.5) product are in perfect agreement with the standard diffraction card. This indicates that the sample prepared by the ultra-high temperature microwave solid-state method is free of impurities and has high purity, demonstrating the effectiveness of the microwave-assisted method. In contrast, the XRD of the SrS:1%Sm synthesized by the solid-state method in Comparative Example 1 differs significantly from the standard diffraction card. Its diffraction peaks indicate that the product synthesized by the solid-state method contains many impurities and has low purity. In summary, the spectra demonstrate that high-purity SrS (i.e., when x = 0) and SrS:x%Sm (0 < x ≤ 1.5) materials with luminescent matrix can be successfully synthesized under microwave assistance.

[0145] The samples from Examples 5 and 2 were irradiated with excitation light sources of different wavelengths to obtain the matrix material and the doped rare-earth ion luminescent material, respectively. Figure 4 The emission pattern and long afterglow phenomenon of the material were observed, and then the emission wavelength of the material was collected using a fluorescence instrument to obtain... Figure 5 By analyzing the emission colors of the material excited by light sources of different excitation wavelengths and collecting the emission spectra, it can be concluded that a simple luminescent matrix material can be obtained using the microwave-assisted ultra-high temperature method, and a single-doped material achieving multi-color emission can also be obtained. The luminescent matrix emits green light under ultraviolet light excitation. After single-doping with samarium ions, it emits orange-yellow light under short-wavelength ultraviolet light excitation, and under long-wavelength ultraviolet light, it emits the same green light as the matrix. The emission spectra under different excitation sources show that under short-wavelength ultraviolet light irradiation, SrS:1%Sm mainly exhibits the characteristic emission peak of samarium ions, and the matrix also emits a peak, but the peak intensity is low, so the material emits orange-yellow light. Under long-wavelength ultraviolet light irradiation, SrS:1%Sm mainly emits light from the SrS matrix, so the material emits green light, while the long afterglow is the characteristic orange-yellow color of samarium ions.

[0146] The samples from Examples 2 and 5-7 were tested using a fluorescence spectrometer to obtain photoluminescence spectra with different samarium ion doping concentrations. The results are as follows: Figure 6 As shown in the figure, SrS synthesized by the ultra-high temperature microwave solid-state method exhibits matrix luminescence. The SrS:x%Sm (0 < x ≤ 1.5) material exhibits the typical emission peak shape of samarium ions, as well as the emission peak of matrix SrS. The results show that the optimal combination of samarium ion characteristic emission peak intensity and SrS matrix luminescence intensity occurs when the samarium ion doping concentration is 1%. At low doping concentrations, the SrS matrix luminescence intensity is high while the samarium ion characteristic peak intensity is low. At high doping concentrations, the samarium ion characteristic luminescence intensity is high, while the SrS matrix-assisted luminescence intensity is low. At a doping concentration of 1%, SrS:1%Sm exhibits the best matrix luminescence with samarium ion characteristic luminescence. The optimal excitation wavelength is 207 nm, and the emission wavelength is 604 nm. With effective excitation, the photoluminescence color of the material can be controlled.

[0147] Because SrS:1%Sm exhibits the best luminescence effect, it was selected for further experiments with different microwave times. Samples from Examples 1-4 and Comparative Example 1 were placed in a fluorescence spectrometer for testing, and the photoluminescence spectra of SrS:1%Sm at different microwave times were obtained. The results are as follows: Figure 7As shown in the figure, the SrS:1%Sm material synthesized by the ultra-high temperature microwave solid-state method exhibits significant SrS matrix luminescence and characteristic samarium ion luminescence at 15 min of microwave time, but no SrS matrix luminescence at other times, making fluorescence modulation impossible. The figure also shows that the SrS:1%Sm material synthesized by the solid-state method in Comparative Example 1 lacks characteristic samarium ion luminescence, indicating that samarium ions are not incorporated into the material, resulting in only weak SrS matrix luminescence, which is significantly weaker than the SrS:1%Sm material synthesized by the ultra-high temperature microwave solid-state method. Therefore, the solid-state method in Comparative Example 1 cannot incorporate samarium ions for fluorescence modulation, nor does it exhibit significant matrix luminescence.

[0148] Because the luminescent materials synthesized by the ultra-high temperature microwave solid-state method in Examples 1-7 exhibited good XRD and photoluminescence spectra, and Example 2 demonstrated good luminescence performance, we selected the sample from Example 2 for further testing and characterization. The synthesis conditions of Example 2 were used for the subsequent synthesis of materials.

[0149] The sample from Example 2 was placed in a fluorescence spectrometer for testing. The emission wavelength of the sample in the 200nm-400nm range from the excitation source was measured to obtain... Figure 8 A two-dimensional contour map. (Through...) Figure 8 It can be seen that SrS:1%Sm is excited within the range of 200nm-350nm, while the optimal excitation wavelength for the matrix is ​​within the range of 260nm-290nm. The optimal excitation wavelength ranges for the three different characteristic emission peaks of samarium ions vary: the excitation peak at 584nm has the strongest emission within the range of 255nm-295nm, the excitation peak at 604nm has the strongest emission within the range of 250nm-300nm, and the emission peak at 612nm has the strongest emission around 274nm. Different emission intensities can be controlled using the two-dimensional emission contour plot of SrS:1%Sm, thus allowing the material to exhibit different luminescent colors.

[0150] The samples in Example 2 were charged with monochromatic light at wavelengths of 254 nm, 275 nm, and 310 nm for two minutes, respectively. The changes in afterglow emission intensity at 604 nm were then measured. Figure 9 The afterglow decay curve. From Figure 9 It can be seen that after excitation at a wavelength of 275nm, the emission intensity at 604nm is still significantly higher than the background intensity within 2 minutes, which confirms its excellent long afterglow performance.

[0151] The sample from Example 2 was observed using a scanning electron microscope, and the results were obtained. Figure 10 .Depend on Figure 10Scanning electron microscopy images reveal that the microstructure of the SrS:1%Sm matrix luminescent single-doped material consists of porous nanoparticles, a significant characteristic of samples synthesized using the microwave ultra-high temperature assisted method. In conclusion, the ultra-high temperature microwave solid-state method can yield luminescent matrices and uniformly doped materials.

[0152] The present invention has been described in detail with reference to the foregoing embodiments. Those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a matrix-assisted multicolor luminescent material, characterized in that, The chemical formula for matrix-assisted multicolor luminescent materials is: SrS:x%Sm; where 0<x≤1.5; The preparation method includes the following steps: Step (1): Prepare the mixed powder SrS, boric acid and Sm2O3 are mixed. SrS and Sm2O3 are mixed in a molar ratio of 1:0 to 1:0.

015. The amount of boric acid added is 2 to 4% of the mass of SrS and Sm2O3. Ethanol is then added and the mixture is ground until homogeneous to obtain a mixed powder. Step (II) Preparing the reaction apparatus The mixed powder is placed in a raw material storage bottle and then placed in a reactor. The reactor is wrapped with activated carbon powder. The reactor is then placed in the cavity of a heat-resistant brick assembly to obtain a reaction device equipped with the mixed powder. Step (3) Microwave reaction The reaction device containing the mixed powder was placed on the circumference 5 cm from the center of the microwave oven reactor. The microwave reaction was carried out for 10-30 minutes at a power of 1000 W, cooled for 1 hour, and then ground to obtain the matrix-assisted multicolor luminescent material. Add 3 ml of ethanol to every 1 g of raw material; after adding ethanol, grind the raw material to 150-200 mesh to obtain the mixed powder; The activated carbon powder is a mixed carbon powder with a mesh size of 20 to 50; the mass ratio of activated carbon powder to mixed powder is 20:

1. The activated carbon powder is laid at the bottom of the reactor, and the activated carbon powder filling can cover 1 / 2 of the height of the raw material storage bottle; The heat-resistant brick assembly includes a heat-resistant brick cover, a heat-resistant brick body, and a heat-resistant brick bottom arranged from top to bottom, and the heat-resistant brick cover, heat-resistant brick body, and heat-resistant brick bottom surround and form the cavity.

2. The application of the luminescent material prepared by the matrix-assisted multicolor luminescent material preparation method according to claim 1, characterized in that, The matrix-assisted multicolor luminescent material is applied to a transparent anti-counterfeiting film.

3. The application according to claim 2, characterized in that, The transparent anti-counterfeiting film is prepared by mixing matrix-assisted multicolor luminescent material and PDMS colloid evenly to obtain a mixed gel-like liquid, then placing the mixed gel-like liquid in a mold and heating it at a temperature of 40~50℃ for 6~8 hours to obtain a transparent anti-counterfeiting film with matrix-assisted luminescence multi-stimulus response characteristics.

4. The application according to claim 3, characterized in that, The mass ratio of the matrix-assisted multicolor luminescent material to the PDMS colloid is 1:2.5 to 1:3.5.

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