Photochromic ceramic and preparation method and application thereof

Abstract

The application provides a photochromic ceramic and a preparation method and application thereof. The photochromic ceramic has a chemical composition formula of La2MgSnO6:x%Er, y%Fe, wherein x=0.5-5, and y=0.13-3. The photochromic ceramic exhibits brown under excitation of 275nm wavelength light, exhibits white under excitation of 365nm wavelength light, and exhibits continuous repeatable color change of brown-white-brown under alternating excitation of 275nm wavelength light and 365nm wavelength light. Green up-conversion luminescence and green down-conversion luminescence are generated under excitation of 980nm wavelength light and 365nm wavelength light, and the luminescence can be statically and dynamically regulated by the color change characteristics, thereby being beneficial to protecting information security. The application further provides a preparation method and application of the photochromic ceramic.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photochromic materials, and particularly relates to a photochromic ceramic as well as a preparation method and application thereof. BACKGROUND

[0002] A photochromic material is a material that can reversibly change color under the stimulation of external light. Based on the change of the color of the material, the absorption spectrum, the refractive index, etc. change. Therefore, the photochromic material has important applications in the fields of optical information storage, carbon paper, molecular switches, display, anti-forgery marks, logic gates, optical / electronic devices, etc. The photochromic material includes organic photochromic material, inorganic photochromic material and organic-inorganic hybrid photochromic material. Traditional organic photochromic materials are furan, pyridine, diarylethene, etc., but the stability at high temperature is not good, and heating can cause irreversible damage to the material structure, and the chemical stability is not good.

[0003] Compared with traditional organic materials, inorganic photochromic materials have the advantages of good color development thermal stability and good fatigue resistance, but there are still problems such as single light emission regulation means and static state, which are not conducive to protecting information security. SUMMARY

[0004] The present application aims to at least solve one of the above-mentioned technical problems in the prior art. To this end, the present application provides a photochromic ceramic, which exhibits a brown color under excitation of 275 nm wavelength light, exhibits a white color under excitation of 365 nm wavelength light, and exhibits a continuous repeatable color change of brown-white-brown under alternating excitation of 275 nm wavelength light and 365 nm wavelength light. Under excitation of 980 nm wavelength light and 365 nm wavelength light, green upconversion luminescence and green downconversion luminescence are generated, and the color change characteristics can be used to statically and dynamically regulate the luminescence, which is conducive to protecting information security.

[0005] The present application also provides a preparation method of the photochromic ceramic.

[0006] The present application also provides an application of the photochromic ceramic in the field of anti-forgery and information storage.

[0007] The first aspect of the present application provides a photochromic ceramic, which has a chemical composition formula of La2MgSnO6:x%Er,y%Fe, wherein x=0.5-5, y=0.13-3.

[0008] One of the technical solutions of the present application about the photochromic ceramic has at least the following beneficial effects:

[0009] The present application combines Er with inorganic photochromic materials, and uses the color change effect to regulate the upconversion luminescence under excitation of 980 nm, which is suitable for anti-forgery and information storage.

[0010] The photochromic ceramic of the present application exhibits brown under excitation of light at a wavelength of 275 nm, white under excitation of light at a wavelength of 365 nm, and brown-white-brown continuous repeatable color change under alternating excitation of light at a wavelength of 275 nm and light at a wavelength of 365 nm. Green up-conversion luminescence and green down-conversion luminescence are generated under excitation of light at a wavelength of 980 nm and light at a wavelength of 365 nm, and the luminescence thereof can be regulated statically and dynamically, respectively, by the color change characteristics, which is conducive to protecting information security. The problem of single and static luminescence regulation means existing in traditional organic materials and inorganic color-changing materials is solved.

[0011] According to some embodiments of the present application, x=1 and y=0.25.

[0012] According to some embodiments of the present application, the photochromic ceramic exhibits brown under excitation of light at a wavelength of 275 nm and white under excitation of light at a wavelength of 365 nm.

[0013] According to some embodiments of the present application, the photochromic ceramic exhibits brown-white-brown continuous repeatable color change under alternating excitation of light at a wavelength of 275 nm and light at a wavelength of 365 nm.

[0014] According to some embodiments of the present application, the photochromic ceramic generates green up-conversion luminescence and green down-conversion luminescence under excitation of light at a wavelength of 980 nm and light at a wavelength of 365 nm.

[0015] The second aspect of the present application provides a method for preparing the photochromic ceramic, comprising the following steps:

[0016] S1: uniformly mixing a lanthanum source, a magnesium source, a tin source, an erbium source and an iron source according to a molar ratio and then pressing into a shape;

[0017] S2: heat-treating the material obtained in step S1 to obtain the photochromic ceramic.

[0018] The technical scheme of the preparation method of the photochromic ceramic has at least the following beneficial effects:

[0019] The preparation method of the present application does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are easy to obtain, the production cost is low, and the industrial production is easy.

[0020] According to some embodiments of the present application, the lanthanum source comprises La2O3.

[0021] According to some embodiments of the present application, the magnesium source comprises MgO.

[0022] According to some embodiments of the present application, the tin source comprises SnO2.

[0023] According to some embodiments of the present application, the erbium source comprises Er2O.

[0024] According to some embodiments of the present application, the iron source comprises Fe2O3.

[0025] According to some embodiments of the present application, the temperature range of the heat treatment is 1500-1700℃.

[0026] According to some embodiments of the present application, the temperature range of the heat treatment is about 1600℃.

[0027] According to some embodiments of the present application, the time range of the heat treatment is 4-10h.

[0028] According to some embodiments of the present application, the time range of the heat treatment is 6-10h.

[0029] According to some embodiments of the present application, the time range of the heat treatment is about 6h.

[0030] The third aspect of the present application provides the application of the photochromic ceramic in the field of anti-counterfeiting and information storage.

[0031] The present application relates to a technical solution of the application of the photochromic ceramic in the field of anti-counterfeiting and information storage, which has at least the following beneficial effects:

[0032] Multi-wavelength excitation repeatable color change: the photochromic ceramic can exhibit brown and white under the excitation of 275nm and 365nm wavelength light, and realize continuous repeatable color change of brown-white-brown under the alternative excitation of the two wavelengths. This multi-wavelength excitation characteristic makes the ceramic have a unique color change mode, which is helpful for anti-counterfeiting identification.

[0033] Light emission regulation and information storage: the ceramic can produce green up-conversion luminescence and green down-conversion luminescence under the excitation of 980nm wavelength light and 365nm wavelength light, and can regulate its luminescence statically and dynamically respectively through the color change characteristic. This luminescence regulation characteristic makes the ceramic applicable to the field of information storage, such as serving as a programmable fluorescent marker.

[0034] Information security protection: due to the static and dynamic luminescence regulation capability of the ceramic, this characteristic can be used to realize the protection of information. For example, under specific excitation conditions, the luminescence color of the ceramic can be changed, thereby realizing dynamic information encryption or identification, increasing the anti-counterfeiting property and information security.

[0035] Strong resistance to counterfeiting: The special photochromic properties and luminescence control properties of the photochromic ceramic increase the resistance to counterfeiting of the product. This is particularly important in the field of anti-counterfeiting, as it becomes more difficult to manufacture counterfeit products.

[0036] Durability and stability: Ceramic materials generally have good durability and stability, which can adapt to various environmental conditions. This is crucial for long-term information storage and anti-counterfeiting requirements.

[0037] Overall, the application of such photochromic ceramics is expected to bring more innovation and security in the field of anti-counterfeiting and information storage. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 X-ray powder diffraction patterns of samples provided for Example 1 and Comparative Examples 1-2.

[0039] Figure 2 Comparison chart of diffuse reflectance spectra before and after 275 nm irradiation and sample photos of samples provided for Example 1 and Comparative Examples 1-2.

[0040] Figure 3 Down-conversion fluorescence emission spectrum of the sample provided for Example 1 under 379 nm excitation and excitation spectrum under monitoring of 547 nm down-conversion emission.

[0041] Figure 4 Up-conversion emission spectrum of the sample provided for Example 1 under 980 nm excitation and superimposed absorption spectrum after color change under 275 nm irradiation.

[0042] Figure 5 Change in diffuse reflectance spectrum of the sample provided for Example 1 after color change under 275 nm irradiation under 365 nm to 980 nm light irradiation.

[0043] Figure 6 Pattern change photos of the sample provided for Example 1 after color change under 275 nm irradiation under 365 nm and 980 nm light irradiation. DETAILED DESCRIPTION

[0044] The following are specific embodiments of the present application, and the technical solutions of the present application are further described in conjunction with the embodiments, but the present application is not limited to these embodiments.

[0045] In some embodiments of the present application, a photochromic ceramic is provided, with a chemical composition formula of La2MgSnO6: x%Er, y%Fe, where x = 0.5-5, y = 0.13-3.

[0046] It can be understood that the present application combines Er with inorganic photochromic materials, utilizes the color change effect to regulate the up-conversion luminescence excited by 980nm, and is suitable for anti-counterfeiting and information storage.

[0047] The photochromic ceramic of the present application exhibits brown under excitation of 275nm wavelength light, exhibits white under excitation of 365nm wavelength light, and exhibits continuous repeatable color change of brown-white-brown under alternating excitation of 275nm wavelength light and 365nm wavelength light. Green up-conversion luminescence and green down-conversion luminescence are generated under excitation of 980nm wavelength light and 365nm wavelength light, and the luminescence can be regulated statically and dynamically respectively through the color change characteristics, which is beneficial to protecting information security. The problem of single luminescence regulation means and staticity of traditional organic materials and inorganic color-changing materials is solved.

[0048] In some embodiments of the present application, x=1 and y=0.25.

[0049] In some embodiments of the present application, the photochromic ceramic exhibits brown under excitation of 275nm wavelength light, and exhibits white under excitation of 365nm wavelength light.

[0050] In some embodiments of the present application, the photochromic ceramic exhibits continuous repeatable color change of brown-white-brown under alternating excitation of 275nm wavelength light and 365nm wavelength light.

[0051] In some embodiments of the present application, the photochromic ceramic generates green up-conversion luminescence and green down-conversion luminescence under excitation of 980nm wavelength light and 365nm wavelength light.

[0052] In some other embodiments of the present application, a method for preparing the photochromic ceramic is provided, comprising the following steps:

[0053] S1: uniformly mixing a lanthanum source, a magnesium source, a tin source, an erbium source and an iron source according to a molar ratio, and then pressing into a shape;

[0054] S2: heat-treating the material obtained in step S1 to obtain the photochromic ceramic.

[0055] It can be understood that the preparation method of the present application does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are easy to obtain, the production cost is low, and the industrial production is easy.

[0056] In some embodiments of the present application, the lanthanum source comprises La2O3.

[0057] In some embodiments of the present application, the magnesium source comprises MgO.

[0058] In some embodiments of the present application, the tin source comprises SnO2.

[0059] In some embodiments of the present application, the erbium source comprises Er2O.

[0060] In some embodiments of the present application, the iron source comprises Fe2O3.

[0061] In some embodiments of the present application, the heat treatment temperature ranges from 1450℃ to 1650℃.

[0062] In some embodiments of the present application, the heat treatment temperature is about 1600℃.

[0063] In some embodiments of the present application, the heat treatment time ranges from 4h to 10h.

[0064] In some embodiments of the present application, the heat treatment time ranges from 6h to 10h.

[0065] In some embodiments of the present application, the heat treatment time is about 6h.

[0066] In some other embodiments of the present application, the application of the photochromic ceramic in the field of anti-counterfeiting and information storage is provided.

[0067] It can be understood that the multi-wavelength excitation can repeat the color change: the photochromic ceramic can present brown and white under the excitation of 275nm and 365nm wavelength light, and realize the continuous repeatable color change of brown-white-brown under the alternative excitation of the two wavelengths. The multi-wavelength excitation characteristics make the ceramic have a unique color change mode, which is helpful for anti-counterfeiting identification.

[0068] Light emission regulation and information storage: the ceramic can produce green up-conversion luminescence and green down-conversion luminescence under the excitation of 980nm wavelength light and 365nm wavelength light, and can regulate its luminescence statically and dynamically respectively through the color change characteristics. The light emission regulation characteristics make the ceramic can be used in the field of information storage, such as as a programmable fluorescent marker.

[0069] Information security protection: because the ceramic has the static and dynamic light emission regulation ability, this feature can be used to realize the protection of information. For example, under certain excitation conditions, the luminescence color of the ceramic can be changed, so as to realize dynamic information encryption or identification, increase the anti-counterfeiting and information security.

[0070] Strong resistance to imitation: the special photochromic and light emission regulation characteristics of the photochromic ceramic increase the resistance to imitation of the product. This is especially important in the field of anti-counterfeiting, because it becomes more difficult to manufacture counterfeit products.

[0071] Durability and stability: Ceramic materials generally have good durability and stability, which can adapt to various environmental conditions. This is crucial for long-term information storage and anti-counterfeiting identification requirements.

[0072] Overall, the application of such photochromic ceramics is expected to bring more innovation and security in the field of anti-counterfeiting and information storage.

[0073] The technical solutions of the present application will be better understood in combination with specific examples and comparative examples below.

[0074] It should be noted that all raw materials in the examples and comparative examples are obtained from commercial channels.

[0075] Example 1

[0076] The chemical composition formula of the photochromic ceramic of this example is:

[0077] La 1.99 Er 0.01 MgSn 0.9975 Fe 0.0025 O6(La2MgSnO6:1%Er,0.25%Fe).

[0078] It is prepared according to the following method:

[0079] According to the general formula La 2-x MgSn 1-y O6 design doped Er 3+ The doping amount x of the activated ion is 1mol%, and the chemical stoichiometry y of Fe in the design expression is 0.25%.

[0080] La2O3, MgO, SnO2, Er2O3 and Fe2O3 are selected as starting raw materials, and five kinds of compound raw materials are weighed according to the stoichiometric ratio of each element, and the molar ratio of each element is La:Mg:Sn:Er:Fe=1.99:1:0.9975:0.01:0.0025. The product corresponding to La2MgSnO6:1%Er,0.25%Fe.

[0081] Mix and grind to obtain a mixture, and press the mixture into a round sheet.

[0082] Under air conditions, the obtained round sheet is kept at a temperature of 1600℃ for 6h, and after cooling to room temperature, La2MgSnO6:Er,Fe photochromic luminescent anti-counterfeiting ceramic material ceramic sheet is obtained.

[0083] Comparative Example 1

[0084] The photochromic ceramic of this comparative example is not doped with Fe, and the chemical composition formula is: La 1.99 Er 0.01MgSnO6(La2MgSnO6:1%Er).

[0085] According to the following method, La2MgSnO6:1%Er is prepared by selecting La2O3, MgO, SnO2 and Er2O3 as starting materials, and taking the three kinds of compound raw materials according to the stoichiometric ratio of each element, the molar ratio of each element being La:Mg:Sn = 2:1:1, and the corresponding product is La2MgSnO6. 2-x MgSnO6 designed to be doped with Er 3+ The doping amount x of the active ion is 1%.

[0086] La2O3, MgO, SnO2 and Er2O3 are selected as starting materials, and the four kinds of compound raw materials are weighed according to the stoichiometric ratio of each element, the molar ratio of each element being La:Mg:Sn:Er = 1.99:1:1:0.01, and the corresponding product is La2MgSnO6:1%Er.

[0087] The mixture is uniformly mixed and ground to obtain a mixed material, and the mixed material is pressed into a round sheet.

[0088] The round sheet is obtained under air condition at a temperature of 1600℃ for 6h, and La2MgSnO6:Er material ceramic sheet is obtained after cooling to room temperature.

[0089] Comparative Example 2

[0090] The photochromic ceramic of the present comparative example is not doped with Fe and Er, and the chemical composition formula is La2MgSnO6.

[0091] According to the following method, La2MgSnO6:1%Er is prepared by selecting La2O3, MgO, SnO2 and Er2O3 as starting materials, and taking the three kinds of compound raw materials according to the stoichiometric ratio of each element, the molar ratio of each element being La:Mg:Sn = 2:1:1, and the corresponding product is La2MgSnO6.

[0092] The round sheet is obtained under air condition at a temperature of 1600℃ for 6h, and La2MgSnO6 material ceramic sheet is obtained after cooling to room temperature.

[0093] Performance test

[0094] The performance of the materials (samples) provided by Example 1 and Comparative Examples 1-2 is determined.

[0095] Figure 1 The X-ray powder diffraction pattern of the samples provided by Example 1 and Comparative Examples 1-2 is tested by using a D8 ADVANCE X-ray powder diffractometer of Bruker Company, Germany.

[0096] From the X-ray powder diffraction patterns of the samples provided by Example 1 and Comparative Examples 1-2, it can be seen that the obtained samples are all La2MgSnO6 pure phase. Figure 1 From the X-ray powder diffraction patterns of the samples provided by Example 1 and Comparative Examples 1-2, it can be seen that the obtained samples are all La2MgSnO6 pure phase.

[0097] Figure 2The comparative diagram of the diffuse reflection spectra of the sample provided for Example 1 and Comparative Examples 1-2 before and after irradiation at 275 nm and the sample photo.

[0098] From Figure 2 It can be seen that the sample in Example 1 co-doped with Fe and Er has a more significant discoloration effect.

[0099] Figure 3 The down-conversion fluorescence emission spectrum of the sample provided for Example 1 under excitation at 379 nm and the excitation spectrum under monitoring of the down-conversion emission at 547 nm.

[0100] From Figure 3 It can be seen that the sample in Example 1 can be excited by a 365 nm light source.

[0101] Figure 4 The up-conversion emission spectrum of the sample provided for Example 1 under excitation at 980 nm and the schematic diagram of the increased absorption spectrum after discoloration by irradiation at 275 nm.

[0102] From Figure 4 It can be seen that the sample in Example 1 can be excited by a 980 nm light source, and the emission range completely overlaps with the discoloration absorption range thereof.

[0103] Figure 5 The diffuse reflection spectrum changes of the sample provided for Example 1 after discoloration by irradiation at 275 nm under irradiation of 365 nm to 980 nm light.

[0104] From Figure 5 It can be seen that 365 nm can effectively eliminate the discoloration effect, while 980 nm has no effect on the discoloration effect.

[0105] Figure 6 The pattern change photo of the sample provided for Example 1 after discoloration by irradiation at 275 nm under irradiation of 365 nm and 980 nm light.

[0106] From Figure 6 It can be seen that it indicates that under excitation of 980 nm near-infrared and 365 nm ultraviolet light, visible green up-conversion luminescence and green down-conversion luminescence are generated, and the luminescence thereof can be respectively statically and dynamically regulated by the discoloration characteristics.

[0107] The above describes the present application in detail in combination with examples, but the present application is not limited to the above examples, and within the knowledge range possessed by those skilled in the art, various changes can be made without departing from the purpose of the present application.

Claims

1. A photochromic ceramic, characterized in that, The chemical composition formula is La2MgSnO6:xmol%Er, ymol%Fe, wherein x=0.5-5, y=0.13-3; The photochromic ceramic exhibits brown under 275nm wavelength light excitation and white under 365nm wavelength light excitation; The photochromic ceramic exhibits brown-white-brown continuous repeated color change under alternating excitation of 275nm wavelength light and 365nm wavelength light; The photochromic ceramic generates green upconversion luminescence and green downconversion luminescence under excitation of 980nm wavelength light and 365nm wavelength light.

2. Photochromic ceramic according to claim 1, characterized in that x=1, y=0.

25.

3. A method of making the photochromic ceramic of claim 1, characterized in that, The method comprises the following steps: S1: uniformly mixing a lanthanum source, a magnesium source, a tin source, an erbium source and an iron source according to a molar ratio and then pressing into a shape; S2: heat treating the material obtained in step S1 to obtain the photochromic ceramic.

4. The method of claim 3, wherein, The lanthanum source comprises La2O3; and / or, the magnesium source comprises MgO; and / or, the tin source comprises SnO2; and / or, the erbium source comprises Er2O3; and / or, the iron source comprises Fe2O3.

5. The method of claim 3, wherein, The temperature range of the heat treatment is 1450-1650℃.

6. The method of claim 3, wherein, The time range of the heat treatment is 4-10h.

7. Application of the photochromic ceramic of claim 1 in the field of anti-counterfeiting and information storage.

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