Preparation method and application of irreversible photochromic Ag / Ta2O5 core-shell particles

Abstract

The invention provides a preparation method of irreversible photochromic Ag / Ta2O5 core-shell particles and application of the irreversible photochromic Ag / Ta2O5 core-shell particles. The preparation method comprises the following steps: S1, photo-deposition: mixing a TaCl5 solution precursor and an AgNO3 solution, carrying out photo-deposition, and then drying; and S2, calcining: calcining the product obtained in the step S1, and cooling to obtain the Ag / Ta2O5 core-shell particles. According to the Ag / Ta2O5 core-shell particle prepared by the preparation method disclosed by the invention, the surface of the metal particle is coated with the oxide, the Ag / Ta2O5 core-shell particle has an obvious photochromic effect after being induced by ultraviolet light, and after the ultraviolet light is removed, the color does not fade.

Description

Technical Field

[0001] This invention relates to the field of oxide photochromic materials technology, and more specifically, to a method for preparing irreversible photochromic Ag / Ta2O5 core-shell particles and their applications. Background Technology

[0002] Photochromic materials are a class of materials whose color changes under light. Their color-changing mechanism mainly involves processes such as electron and ion implantation and extraction, two-electron transitions, and electron transfer within the crystal lattice. These materials exhibit rapid response, high stability, and long lifetime, thus showing great application potential in fields such as information storage, smart windows, sensors, and sunglasses. Photochromic materials have become a research hotspot due to their excellent properties.

[0003] Photochromic materials are generally classified into two main categories: organic and inorganic compounds. Inorganic photochromic substances commonly include metal halides and transition metal oxides. Typically, photochromic materials exhibit reversible color changes, meaning they display one color under natural light and change to another color when exposed to ultraviolet light, returning to their original color when the ultraviolet light is removed. However, for some anti-counterfeiting technologies, such as anti-counterfeiting labels or inks, the label color changes and remains unchanged for a long time after being exposed to light of a specific wavelength, making it difficult to replicate and thus enhancing the anti-counterfeiting effect. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects or deficiencies in the prior art and provide a method for preparing irreversible photochromic Ag / Ta2O5 core-shell particles.

[0005] Another object of the present invention is to provide irreversible photochromic Ag / Ta2O5 core-shell particles prepared by the aforementioned method.

[0006] Another object of the present invention is to provide the application of the aforementioned irreversible photochromic Ag / Ta2O5 core-shell particles.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0009] S1. Mix the TaCl5 solution precursor and AgNO3 solution, perform photodeposition, and then dry.

[0010] S2. The product obtained in step S1 is calcined and cooled to obtain Ag / Ta2O5 core-shell particles.

[0011] This invention provides a method for preparing irreversible photochromic Ag / Ta2O5 core-shell particles. By using photodeposition to deposit oxides on the surface of metal particles, the resulting irreversible photochromic Ag / Ta2O5 core-shell particles exhibit good color response after being irradiated with 254nm ultraviolet light, and the color does not fade after the ultraviolet light is removed.

[0012] In some preferred embodiments, the calcination temperature in step S2 is 200–700°C. By adjusting the calcination temperature, the irreversible photochromic Ag / Ta₂O₅ core-shell particles can be controlled to exhibit different color responses under ultraviolet light irradiation.

[0013] It should be noted that the calcination temperature in step S2 of the present invention is 200 to 700°C, for example, but not limited to 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, or 700°C, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0014] Furthermore, the calcination temperature in step S2 is 200–500°C. Within this calcination temperature range, the obtained irreversible photochromic Ag / Ta2O5 core-shell particles exhibit a more pronounced color-changing effect.

[0015] In some preferred embodiments, the calcination time in step S2 is 1 to 6 hours.

[0016] In some preferred embodiments, the heating rate of calcination in step S2 is 5°C / min.

[0017] In some preferred embodiments, the calcination in step S2 specifically involves adding the product obtained in step S1 to ethanol, grinding for 5 minutes, and then placing it in a muffle furnace for calcination.

[0018] In some preferred embodiments, the molar ratio of AgNO3 to TaCl5 in step S1 is (1-10):200, for example, but not limited to, 1:200, 2:200, 3:200, 4:200, 5:200, 6:200, 7:200, 8:200, 9:200 or 10:200, etc., and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the specific values ​​included in the range will not be exhaustively listed in this invention.

[0019] Furthermore, the molar ratio of AgNO3 to TaCl5 in step S1 is (3-5):200. Within this molar ratio range, the obtained irreversible photochromic Ag / Ta2O5 core-shell particles exhibit a more pronounced color-changing effect.

[0020] In some preferred embodiments, the photodeposition time in step S1 is 20 to 60 minutes.

[0021] Specifically, the photodeposition in step S1 is performed with the xenon lamp turned on at room temperature.

[0022] Specifically, the xenon lamp is a 300W full-spectrum xenon lamp light source.

[0023] In some preferred embodiments, the photodeposition in step S1 is performed under magnetic stirring conditions.

[0024] Specifically, the rotation speed of the magnetic stirrer is 350 to 1000 rpm.

[0025] In some preferred embodiments, the TaCl5 solution precursor in step S1 is prepared by the following method:

[0026] TaCl5 powder was dissolved in a solvent to prepare a solution, and then sonicated to obtain a TaCl5 solution precursor.

[0027] Specifically, the ultrasound duration is 20–30 minutes.

[0028] In some preferred embodiments, the ultrasonic product is purged with nitrogen gas at room temperature for 5–20 min to obtain a TaCl5 solution precursor.

[0029] The present invention also provides irreversible photochromic Ag / Ta2O5 core-shell particles prepared by the above preparation method.

[0030] In some preferred embodiments, the irreversible photochromic Ag / Ta2O5 core-shell particles have a core-shell structure, wherein the shell of the Ag / Ta2O5 core-shell particles comprises Ta2O5, and the core comprises Ag particles.

[0031] This invention also protects the application of the aforementioned irreversible photochromic Ag / Ta2O5 core-shell particles in the preparation of anti-counterfeiting materials, such as anti-counterfeiting labels or inks.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] This invention provides a method for preparing irreversible photochromic Ag / Ta2O5 core-shell particles. The preparation method involves photodeposition and calcination to coat the surface of metal particles with oxides. After being induced by ultraviolet light, the particles exhibit a significant photochromic effect, and the color remains unchanged after the ultraviolet light is removed. Attached Figure Description

[0034] Figure 1 XRD pattern of Ag / Ta2O5 core-shell particles prepared in Example 2 at 300℃;

[0035] Figure 2 Photochromic images of Ag / Ta2O5 core-shell particles prepared in Example 1 at 200℃ (left side before UV irradiation, right side after UV irradiation);

[0036] Figure 3 Photochromic images of Ag / Ta2O5 core-shell particles prepared in Example 2 at 300℃ (left side before UV irradiation, right side after UV irradiation);

[0037] Figure 4 Photochromic images of Ag / Ta2O5 core-shell particles prepared in Example 3 at 400℃ (left side before UV irradiation, right side after UV irradiation);

[0038] Figure 5 Photochromic images of Ag / Ta2O5 core-shell particles prepared in Example 4 at 500℃ (left side before UV irradiation, right side after UV irradiation);

[0039] Figure 6 Photochromic images of Ag / Ta2O5 core-shell particles prepared in Example 5 at 600℃ (left side before UV irradiation, right side after UV irradiation);

[0040] Figure 7 Photochromic images of Ag / Ta2O5 core-shell particles prepared in Example 6 at 700℃ (left side before UV irradiation, right side after UV irradiation);

[0041] Figure 8 To implement the photochromic effect of Ag / Ta2O5 core-shell particles prepared in 4, 7, and 8, the upper layer is before UV irradiation, and the lower layer is after UV irradiation; from left to right, they correspond to Example 7, Example 4, and Example 8 respectively;

[0042] Figure 9 XPS spectrum of Ag / Ta2O5 core-shell particles prepared in Example 4 at 500℃;

[0043] Figure 10 XPS fine spectrum of Ag core-shell particles Ag / Ta2O5 at 500℃ prepared in Example 4;

[0044] Figure 11 Transmission electron microscopy (TEM) image of Ag / Ta2O5 core-shell particles prepared in Example 4 at 500℃. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below, but the implementation of the present invention is not limited thereto.

[0046] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0047] Example 1

[0048] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0049] S1. Photodeposition:

[0050] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0051] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0052] S13. Mix the above TaCl5 solution precursor with 2000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0053] S2. Calcination: The product obtained in step S1 is added to ethanol and ground for 5 min. It is then placed in a muffle furnace and calcined at 200℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles are obtained, abbreviated as Ag / Ta2O5-200℃.

[0054] Example 2

[0055] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0056] S1. Photodeposition:

[0057] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0058] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0059] S13. Mix the above TaCl5 solution precursor with 2000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0060] S2. Calcination: The product obtained in step S1 is added to ethanol and ground for 5 min. It is then placed in a muffle furnace and calcined at 300℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles are obtained, abbreviated as Ag / Ta2O5-300℃.

[0061] Example 3

[0062] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0063] S1. Photodeposition:

[0064] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0065] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0066] S13. Mix the above TaCl5 solution precursor with 2000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0067] S2. Calcination: The product obtained in step S1 is added to ethanol and ground for 5 min. It is then placed in a muffle furnace and calcined at 400℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles are obtained, abbreviated as Ag / Ta2O5-400℃.

[0068] Example 4

[0069] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0070] S1. Photodeposition:

[0071] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0072] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0073] S13. Mix the above TaCl5 solution precursor with 2000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0074] S2. Calcination: The product obtained in step S1 is added to ethanol and ground for 5 min. It is then placed in a muffle furnace and calcined at 500℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles are obtained, abbreviated as Ag / Ta2O5-500℃.

[0075] Example 5

[0076] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0077] S1. Photodeposition:

[0078] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0079] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0080] S13. Mix the above TaCl5 solution precursor with 2000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0081] S2. Calcination: The product obtained in step S1 is added to ethanol and ground for 5 min. It is then placed in a muffle furnace and calcined at 600℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles are obtained, abbreviated as Ag / Ta2O5-600℃.

[0082] Example 6

[0083] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0084] S1. Photodeposition:

[0085] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0086] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0087] S13. Mix the above TaCl5 solution precursor with 2000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0088] S2. Calcination: The product obtained in step S1 is added to ethanol and ground for 5 min. It is then placed in a muffle furnace and calcined at 700℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles are obtained, abbreviated as Ag / Ta2O5-700℃.

[0089] Example 7

[0090] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0091] S1. Photodeposition:

[0092] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0093] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0094] S13. Mix the above TaCl5 solution precursor with 1000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0095] S2. Calcination: The product obtained in step S1 was added to ethanol and ground for 5 min. It was then placed in a muffle furnace and calcined at 500℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles were obtained.

[0096] Example 8

[0097] A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles includes the following steps:

[0098] S1. Photodeposition:

[0099] S11. Dissolve 1000 mg TaCl5 powder in 300 mL of water to prepare a solution, and then sonicate for 30 min.

[0100] S12. The product after sonication in step S11 is purged with nitrogen gas at room temperature for 5-20 min to obtain the TaCl5 solution precursor.

[0101] S13. Mix the above TaCl5 solution precursor with 3000 μL AgNO3 solution (concentration of 1 mg / 200 μL), perform photodeposition at room temperature with a xenon lamp turned on for 40 min under magnetic stirring at 700 rpm, then cool, filter, and dry at 80 °C.

[0102] S2. Calcination: The product obtained in step S1 was added to ethanol and ground for 5 min. It was then placed in a muffle furnace and calcined at 500℃ for 2 h with a heating rate of 5℃ / min. After natural cooling to room temperature, Ag / Ta2O5 core-shell particles were obtained.

[0103] Comparative Example 1

[0104] Referring to existing technology, Zhou Jiahui. Research on Photochromism and Holographic Storage of Ag / Ta2O5 Nanocomposite Thin Films [D]. Northeast Normal University, 2022. Chapter 2 Preparation of Ag / Ta2O5, the specific steps are as follows:

[0105] S1. The Ta2O5 precursor solution was synthesized using the sol-gel method.

[0106] Solution A: Add surfactant F-127 (0.30 g) to anhydrous ethanol solution (12.65 mL) and stir magnetically at 60 °C for 30 min until F-127 is completely dissolved;

[0107] Solution B: Add 0.60 g of tantalum pentachloride powder to 12.65 mL of anhydrous ethanol solution and stir magnetically at 24 °C for 2 h until the tantalum pentachloride powder is completely dissolved;

[0108] Solution A was slowly added dropwise to solution B, and the mixture was continuously stirred magnetically for 1 hour to ensure that the two components were mixed evenly. Then, 2.0 mL of deionized water was slowly added dropwise to the mixed solution, and the mixture was stirred magnetically for 2 hours. Finally, the mixture was allowed to stand for 15 hours to obtain the Ta2O5 precursor sol solution.

[0109] S2. Ta2O5 nanofilms were prepared by dip-coating method (one-time). The cleaned glass substrate was immersed in the Ta2O5 precursor solution and then removed to obtain a flat Ta2O5 structure. The entire process was carried out by a dipping rate of 0.455 cm / s, a dipping time of 8 s, and a suspension time of 180 s after the film was removed.

[0110] S3. After the product described in step S2 is left to stand at room temperature for 1 hour, it is placed in an annealing furnace and air-annealed at 600°C for 45 minutes, and then magnetron sputtered on its surface for 15 seconds to obtain the final product.

[0111] Test case

[0112] Experimental methods

[0113] 1. XRD test: The core-shell particles Ag / Ta2O5 prepared in Example 2 were subjected to XRD test at 300℃ using a Shimadzu XRD-6000.

[0114] 2. TEM test: The core-shell particles Ag / Ta2O5 prepared in Example 4 were subjected to TEM test at -500℃ using a Talos F200X from ThermoFisher, USA.

[0115] 3. XPS test: The core-shell particles Ag / Ta2O5 prepared in Example 4 were subjected to XPS test at -500℃ using a ThermoScientific Escalab 250Xi.

[0116] 4. Color change performance test: The samples prepared in the above embodiments were photographed under natural light and then irradiated under a 254nm ultraviolet lamp for 120s, with the distance between the ultraviolet lamp and the sample being 1cm; after the irradiation, photographs were taken.

[0117] Experimental results

[0118] The test results for each embodiment and comparative example are shown in Table 1 and Figures 1-11 As shown.

[0119] Table 1. Experimental data for each embodiment and comparative example.

[0120] Does the color fade after 5 days of removing the ultraviolet light source? Example 1 no Example 2 no Example 3 no Example 4 no Example 5 no Example 6 no Example 7 no Example 8 no Comparative Example 1 yes

[0121] from Figure 1 It can be seen that the phase of the prepared sample mainly belongs to the orthorhombic crystal system of Ta2O5 (PDF#25-0955).

[0122] from Figures 2-7 It can be seen that Ag / Ta2O5 core-shell particles undergo different changes under ultraviolet light irradiation with varying calcination temperatures. Ag / Ta2O5 core-shell particles prepared at calcination temperatures of 200–500°C exhibit better color-changing effects. Furthermore, the Ag / Ta2O5 core-shell particles prepared by this invention show color after being irradiated with an ultraviolet lamp, and the color does not fade after the ultraviolet lamp is removed.

[0123] The product obtained in Comparative Example 1 showed color after being irradiated with ultraviolet light, and the color faded after the ultraviolet light was removed.

[0124] from Figure 9 and 10The XPS structure shows that the main components of the Ag / Ta₂O₅ prepared in this invention are Ag, Ta, and O. Among them, Ag mainly exists in the form of metallic Ag.

[0125] from Figure 11 The TEM images show that the prepared Ag / Ta2O5 has a typical core-shell structure.

[0126] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing irreversibly photochromic Ag / Ta2O5 core-shell particles, characterized in that, Includes the following steps: S1. Photodeposition: Mix TaCl5 solution precursor and AgNO3 solution, perform photodeposition, and then dry. S2. Calcination: The product obtained in step S1 is calcined and cooled to obtain Ag / Ta2O5 core-shell particles.

2. The preparation method according to claim 1, characterized in that, The calcination temperature in step S2 is 200–700°C.

3. The preparation method according to claim 2, characterized in that, The calcination temperature in step S2 is 200–500°C.

4. The preparation method according to claim 1, characterized in that, The calcination time in step S2 is 1 to 6 hours.

5. The preparation method according to claim 1, characterized in that, The molar ratio of AgNO3 to TaCl5 in step S1 is (1-10):

200.

6. The preparation method according to claim 1, characterized in that, The photodeposition time in step S1 is 20 to 60 minutes.

7. The preparation method according to claim 1, characterized in that, The TaCl5 solution precursor mentioned in step S1 is prepared by the following method: TaCl5 powder was dissolved in water to prepare a solution, which was then sonicated to obtain a TaCl5 solution precursor.

8. The preparation method according to claim 1, characterized in that, The ultrasound session lasted 20 to 30 minutes.

9. An irreversible photochromic Ag / Ta2O5 core-shell particle, characterized in that, It is prepared by any one of the preparation methods of claims 1 to 8.

10. The application of the irreversible photochromic Ag / Ta2O5 core-shell particles as described in claim 9 in the preparation of anti-counterfeiting materials.

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