Method for in-situ synthesis of mesoporous silica microspheres with room-temperature phosphorescence emission

Abstract

The invention relates to a mesoporous silica microsphere with room temperature phosphorescence emission and a preparation method thereof, and the preparation method comprises the following steps: adding TEA into 25 mL of deionized water to obtain a transparent solution; adding CTAB (Cetyltrimethyl Ammonium Bromide) and glucose into the obtained transparent solution, and stirring for 1 hour at 60 DEG C; adding TEOS (tetraethyl orthosilicate) and sodium salicylate into the mixed solution, continuously stirring for two hours, centrifuging, and drying to obtain white powder. And calcining the obtained white powder in a crucible with a cover to obtain the mesoporous silica microspheres with room-temperature phosphorescence emission. The mesoporous silica microsphere is characterized in that the mesoporous silica microsphere is obtained by an in-situ synthesis method. In addition, the synthesized mesoporous silica microspheres with room-temperature phosphorescence emission have bright cyan phosphorescence after being excited by ultraviolet light, the average phosphorescence lifetime is 0.94 s, and the duration of macroscopic phosphorescence is 10 s after an ultraviolet lamp is turned off. The medicines used for preparation are cheap and easy to obtain, the preparation process is simple and convenient, and complicated and tedious post-treatment steps are not needed. The prepared mesoporous silica microspheres with room-temperature phosphorescence emission can be successfully applied to the fields of information encryption and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of room temperature phosphorescent material preparation, and particularly relates to mesoporous silica microspheres with room temperature phosphorescent emission and a preparation method thereof. Background Art

[0002] Mesoporous silica microspheres have been widely used in many fields such as drug delivery, catalyst carriers and sensing due to their advantages such as high specific surface area, good biocompatibility, excellent chemical stability and high temperature resistance. These characteristics also make them promising as an ideal carrier for phosphorescent materials. Specifically, their ordered mesoporous structure can not only effectively adsorb phosphorescent materials through spatial confinement effects, but also regulate their luminescence properties, thereby realizing the functional application of phosphorescent materials in bioimaging, sensing and anti-counterfeiting identification. However, the high porosity of the mesoporous structure may expose the luminescent center directly to environmental conditions, resulting in phosphorescence quenching caused by factors such as oxygen or water. In addition, the synthesis of mesoporous silica microspheres usually involves multi-step processes such as template method, co-condensation method or sol-gel method, and the loading and modification of the luminescent center often require additional steps, which significantly increases the synthesis cost of the material and hinders its large-scale production and practical application.

[0003] In contrast, in situ synthesis methods are characterized by ease of operation, requiring no complex pretreatment or subsequent tedious separation and purification steps, effectively simplifying the experimental process and reducing synthesis costs. Furthermore, during in situ synthesis, the luminescent center and the matrix form simultaneously, facilitating a closer bond between the luminescent center and the matrix, enhancing the material's stability and functionality. Furthermore, the type of luminescent center plays a key role in the material's phosphorescent properties. Carbon dots, as a new type of optical nanomaterial, offer unique optical properties, high water dispersibility, good biocompatibility, and a wide range of raw material sources, demonstrating broad application potential in fields such as sensing, bioimaging, and optoelectronic devices. In recent years, carbon dots have been considered a promising, environmentally friendly material for achieving room-temperature phosphorescence. However, when using carbon dots as luminescent centers, their inherent tendency to aggregate, leading to phosphorescence quenching, presents an additional challenge. Therefore, developing a simple and easy in situ synthesis method that can achieve stable and efficient phosphorescence emission by manipulating the synthesis process is of great significance, addressing the existing issues of complex luminescent center loading processes, high costs, and environmental susceptibility of phosphorescent properties. Summary of the Invention

[0004] In order to avoid the shortcomings of the prior art, the present invention provides a method for in situ synthesis of mesoporous silica microspheres with room temperature phosphorescence emission.

[0005] One of the purposes of the present invention is to provide a simple and easy in-situ synthesis method.

[0006] A second object of the present invention is to provide mesoporous silica microspheres with room temperature phosphorescence emission.

[0007] The room-temperature phosphorescent mesoporous silica microspheres prepared in this invention are prepared using tetraethyl orthosilicate (TEOS), triethanolamine (TEA), cetyltrimethylammonium bromide (CTAB), and glucose as raw materials via an in-situ synthesis method. The preparation process includes the following specific steps: 1. First, add 0.4-1 mL of TEA to 25 mL of deionized water to obtain a clear solution. 2. Add 0.2-0.6 g CTAB and 0.4 g glucose to the clear solution obtained in step 1, and stir at 60°C for 1 hour to obtain a clear solution; 3. Add 2-4 mL of TEOS and 0.1-0.5 g of sodium salicylate to the clear solution obtained in step 2 and continue stirring for 2 hours to obtain a white solution; 4. Centrifuge the white solution obtained in step 3 at 8000 rpm for 5 minutes using a high-speed centrifuge, remove the supernatant in the centrifuge tube, and obtain a white precipitate; 5. Dry the white precipitate obtained in step 4 in an oven at 60-100°C for 6-24 hours to obtain a white powder; 6. The white powder obtained in step 5 was placed in a crucible with a lid and calcined in a muffle furnace at 400-600° C. for 3 hours to obtain mesoporous silica microspheres with room temperature phosphorescence emission.

[0008] Beneficial effects of the present invention: 1. The present invention provides an in-situ synthesis method for preparing mesoporous silica microspheres with room temperature phosphorescence emission, characterized in that TEOS, TEA, CTAB, glucose and sodium salicylate are used as raw materials and the in-situ synthesis method is used. Only common laboratory equipment is required, and no special equipment is required. The process is simple and easy to operate. 2. The mesoporous silica microspheres with room-temperature phosphorescence obtained by this method have a phosphorescence lifetime of 0.94 s. After turning off the UV light, the long-life phosphorescence lasting 10 s can be observed by the naked eye. 3. The drugs used in the present invention are cheap and readily available, and the preparation process is simple, without the need for complicated and tedious post-processing steps. They are particularly suitable for batch and low-cost preparation and are suitable for industrial-scale production and commercial application. 4. The mesoporous silica microspheres with room temperature phosphorescence emission provided by the present invention can be successfully applied in fields such as information encryption. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction to the drawings will be given below in the description of the embodiments or the prior art. However, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 This is a transmission electron microscope image of mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1 of the present invention.

[0011] Figure 2 This is the X-ray diffraction pattern of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1 of the present invention.

[0012] Figure 3 This is a phosphorescence spectrum of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1 of the present invention.

[0013] Figure 4 This is a diagram of the phosphorescence lifetime of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1 of the present invention.

[0014] Figure 5 These are state diagrams of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Examples 1-3 and Comparative Examples 1-2 under sunlight, under 365 nm ultraviolet light, and after the ultraviolet light is turned off.

[0015] Figure 6 This is a photo of the application of mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1 of the present invention in information encryption. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0018] Unless otherwise specified, the experimental methods described in the following examples are all conventional methods; the reagents and materials described are all commercially available unless otherwise specified.

[0019] Example 1: First, 0.7 mL of TEA was added to 25 mL of deionized water to obtain a clear solution. To this clear solution, 0.4 g of CTAB and 0.4 g of glucose were added, and the mixture was stirred at 60°C for 1 hour. To this mixture, 3 mL of LTEOS and 0.3 g of sodium salicylate were added, and stirring continued for 2 hours to obtain a white solution. The resulting white solution was centrifuged at 8000 rpm for 5 minutes, and the supernatant was removed from the centrifuge tube to obtain a white precipitate. The white precipitate was dried in an 80°C oven for 12 hours to obtain a white powder. The resulting white powder was transferred to a covered crucible and calcined in a muffle furnace at 500°C for 3 hours to obtain mesoporous silica microspheres with room-temperature phosphorescence.

[0020] Example 2: First, 0.4 mL of TEA was added to 25 mL of deionized water to obtain a clear solution. To this clear solution, 0.2 g of CTAB and 0.4 g of glucose were added, and the mixture was stirred at 60°C for 1 hour. To this mixture, 2 mL of LTEOS and 0.1 g of sodium salicylate were added, and stirring continued for 2 hours to obtain a white solution. The resulting white solution was centrifuged at 8000 rpm for 5 minutes, and the supernatant was removed from the centrifuge tube to obtain a white precipitate. The white precipitate was dried in a 60°C oven for 6 hours to obtain a white powder. The white powder was transferred to a covered crucible and calcined in a muffle furnace at 400°C for 3 hours to obtain mesoporous silica microspheres with room-temperature phosphorescence.

[0021] Example 3: First, 1 mL of TEA was added to 25 mL of deionized water to obtain a clear solution. To this clear solution, 0.6 g of CTAB and 0.4 g of glucose were added, and the mixture was stirred at 60°C for 1 hour. To this mixture, 4 mL of TEOS and 0.5 g of sodium salicylate were added, and stirring continued for 2 hours to obtain a white solution. The resulting white solution was centrifuged at 8000 rpm for 5 minutes, and the supernatant was removed from the centrifuge tube to obtain a white precipitate. The white precipitate was dried in a 100°C oven for 24 hours to obtain a white powder. The resulting white powder was transferred to a covered crucible and calcined in a muffle furnace at 600°C for 3 hours to obtain mesoporous silica microspheres with room-temperature phosphorescence.

[0022] Comparative Example 1: First, 0.7 mL of TEA was added to 25 mL of deionized water to obtain a clear solution. To this clear solution, 0.4 g of glucose was added and stirred at 60°C for 1 hour. To this mixture, 3 mL of TEOS and 0.3 g of sodium salicylate were added and stirred for another 2 hours to obtain a white solution. The resulting white solution was centrifuged at 8000 rpm for 5 minutes. The supernatant was removed from the centrifuge tube to obtain a white precipitate. The white precipitate was dried in an 80°C oven for 12 hours to obtain a white powder. The white powder was transferred to a covered crucible and calcined in a muffle furnace at 500°C for 3 hours to obtain mesoporous silica microspheres with room-temperature phosphorescence.

[0023] Comparative Example 2: First, 0.7 mL of TEA was added to 25 mL of deionized water to obtain a clear solution. To this clear solution, 0.4 g of CTAB was added and stirred at 60°C for 1 hour. To this mixture, 3 mL of TEOS and 0.3 g of sodium salicylate were added and stirred for another 2 hours to obtain a white solution. The resulting white solution was centrifuged at 8000 rpm for 5 minutes. The supernatant was removed from the centrifuge tube to obtain a white precipitate. The white precipitate was dried in an 80°C oven for 12 hours to obtain a white powder. The resulting white powder was transferred to a covered crucible and calcined in a muffle furnace at 500°C for 3 hours to obtain mesoporous silica microspheres with room-temperature phosphorescence.

[0024] Figure 1 This is a transmission electron microscope image of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1. Figure 1 It can be seen that the average diameter of the mesoporous silica microspheres with room temperature phosphorescence emission is about 135 nm, and the sample has good dispersion.

[0025] Figure 2 This is the X-ray diffraction image of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1. Figure 2 It can be seen that the mesoporous silica microspheres with room temperature phosphorescence emission are amorphous.

[0026] Figure 3 The phosphorescence spectrum of mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1. Figure 3 It can be seen that when the excitation wavelength is 365 nm, the center of its phosphorescence emission band is around 495 nm.

[0027] Figure 4 This is the phosphorescence lifetime diagram of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Example 1. Figure 4It can be seen that the time-resolved decay spectrum is fitted with a three-exponential function according to the following formula: τ avg =∑α i τ i 2 / ∑α i τ i The average phosphorescence lifetime at room temperature was calculated to be 0.94 s, indicating that the prepared mesoporous silica microspheres with room temperature phosphorescence emission have an excellent long phosphorescence lifetime.

[0028] Figure 5 The following are the state diagrams of the mesoporous silica microspheres with room temperature phosphorescence emission prepared in Examples 1-3 and Comparative Examples 1-2 under sunlight, 365 nm ultraviolet light, and after the light is turned off. Figure 5 It can be seen that Example 1 exhibits the longest visible phosphorescence duration of 10 s; the mesoporous silica microspheres with room temperature phosphorescence emission prepared in other Examples 2-3 and Comparative Examples 1-2 have a relatively short visible phosphorescence duration.

[0029] Figure 6 A photograph shows the application of room-temperature phosphorescent mesoporous silica microspheres prepared in Example 1 in information encryption. As shown, this information encryption model, combined with Morse code, uses samples with different phosphorescence lifetimes. Under both sunlight and 365 nm UV light, the samples display incorrect information. After the UV light is turned off, the message "UJN" can be clearly and accurately deciphered after 8 seconds due to the different phosphorescence lifetimes of the samples.

[0030] Obviously, those skilled in the art may make various modifications and variations to the mesoporous silica microspheres with room temperature phosphorescence emission and the method for preparing the same, without departing from the spirit and scope of the present invention. Thus, to the extent such modifications and variations fall within the scope of the claims and their equivalents, the present invention is intended to encompass such modifications and variations.

Claims

1. A method for in situ synthesis of mesoporous silica microspheres with room temperature phosphorescence emission, comprising the following steps: First, 0.4-1 mL of TEA was added to 25 mL of deionized water to obtain a clear solution. To this clear solution, 0.2-0.6 g of CTAB and 0.4 g of glucose were added, and the mixture was stirred at 60°C for 1 hour. To this mixture, 2-4 mL of LTEOS and 0.1-0.5 g of sodium salicylate were added, and stirring continued for 2 hours to obtain a white solution. The resulting white solution was centrifuged at 8000 rpm for 5 minutes, and the supernatant was removed from the centrifuge tube to obtain a white precipitate. The resulting white precipitate was dried in an oven at 60-100°C for 6-24 hours to obtain a white powder. The resulting white powder was transferred to a covered crucible and calcined in a muffle furnace at 400-600°C for 3 hours to obtain mesoporous silica microspheres with room-temperature phosphorescence.

2. The method for preparing mesoporous silica microspheres with room temperature phosphorescence emission according to claim 1, characterized in that: The amount of TEA used was 0.7 mL, and the amount of CTAB used was 0.4 g.

3. The method for preparing mesoporous silica microspheres with room temperature phosphorescence emission according to claim 1, characterized in that: The amount of TEOS used was 3 mL, and the amount of sodium salicylate used was 0.3 g.

4. Use of mesoporous silica microspheres with room temperature phosphorescence emission obtained by the preparation method according to claim 1, characterized in that: The mesoporous silica microspheres with room temperature phosphorescence emission are used for information encryption.

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