A method for preparing quantum dot-based microcrystalline glass

Abstract

This invention provides a method for preparing quantum dot-based microcrystalline glass, wherein the glass comprises microcrystalline glass powder and quantum dots in a mass ratio of 2.5:1, and the microcrystalline glass powder comprises the following components by mass percentage: SiO₂ 2 : 40-60%; H 3 BO 3 : 25-45%; La 2 O 3 :1-3%; ZnO: 5-12%; Na 2 CO 3 The UV and infrared blocking rates of the glass described in this invention reach approximately 90% before color change, and the visible light transmittance reaches over 80.0%; after color change, the UV blocking rate reaches over 99.0%, the infrared blocking rate is higher than 97%, and the visible light transmittance reaches over 30%.

Description

A method for preparing quantum dot-based glass-ceramics Technical Field

[0001] This invention belongs to the field of glass preparation technology, and in particular relates to a method for preparing microcrystalline glass based on quantum dots. Background Technology

[0002] Sunlight is a major source of heat, with 50% of solar radiation energy in the visible light region, 43% in the infrared region, and 7% in the ultraviolet region. Especially in summer, the operation of numerous air conditioners, fans, and other cooling devices results in enormous energy consumption. Since buildings primarily exchange energy through windows, they require insulated glass to block solar radiation from penetrating the interior, while maintaining high transmittance of visible light and automatically adjusting its color according to radiation intensity.

[0003] Existing technologies offer many solutions with heat insulation effects, but all have certain problems. For example, Chinese patents CN115093131B and CN213167232U both use coating to achieve heat insulation, but the coating contains organic matter, which is prone to oxidation and failure after high-temperature exposure, reducing its service life and reducing or even eliminating its heat insulation effect. Chinese patents CN219320620U and CN217718391U both use electrochromic technology to achieve the color-changing effect. The electrochromic process is complex, requiring multiple components such as a conductive layer, temperature control mechanism, color-changing film, and battery or external power supply. It is expensive, difficult to construct, and not suitable for widespread application in building doors and windows.

[0004] Due to their unique properties, quantum dots have been applied in various fields in recent years. Also known as semiconductor nanocrystals, quantum dots have extremely small nanoscale dimensions. Conduction band electrons, valence band holes, and excitons are confined in three dimensions, giving them special properties such as quantum confinement effects and quantum size effects. When a quantum dot is illuminated, it absorbs photons, exciting electrons in the valence band to jump to the conduction band, creating holes in the valence band. When an electron in the conduction band jumps back to the valence band and recombines directly with the previously vacated hole, a photon is emitted—this is the light emission process of quantum dots. The emission spectrum of quantum dots is tunable; changing the size of the quantum dot adjusts the breadth of its emission spectrum coverage, allowing for high transmittance in the visible light region. However, quantum dots suffer from damp-heat instability, which limits their applications. Summary of the Invention

[0005] In view of this, the present invention aims to overcome the defects in the prior art and proposes a method for preparing microcrystalline glass based on quantum dots.

[0006] Current technologies typically involve mixing the raw materials needed for glass melting with quantum dots before fusing them to prepare quantum dot glass. For example, in preparing perovskite quantum dot microcrystalline glass, it's necessary to investigate the melting temperature to avoid the volatilization of halogens, increasing the experimental difficulty and time. This method also requires the introduction of nucleating agents to promote crystal formation within the glass and reduce the formation of large-sized quantum dots. The introduction of nucleating agents further complicates the microcrystalline glass melting process. Since the small size effect of quantum dots is crucial for their superior performance, controlling the size of quantum dots using nucleating agents while considering the state of the crystals within the microcrystalline glass increases the manufacturing difficulty. This significantly impacts the glass's thermal insulation performance.

[0007] This invention involves first preparing microcrystalline glass, designing its composition, and controlling its Tg temperature at 400℃ and Tf temperature at 640℃. The microcrystalline glass is then crushed to obtain microcrystalline glass powder. This method eliminates the need for nucleating agents and avoids consideration of the volatilization of halogens in perovskite quantum dots, significantly reducing the difficulty of experimental operation.

[0008] Microcrystalline glass powder and quantum dots were mixed in a specific ratio and sintered in a muffle furnace at a temperature higher than the glass's Tg temperature but lower than its Tf temperature. This process coated the quantum dots with the microcrystalline glass powder. Due to the extremely high chemical stability of glass, the coating enhances the stability of the quantum dots, increasing their lifespan. Tests of the glass's ultraviolet and infrared blocking properties and visible light transmittance before and after color change revealed significant differences. The mixing of one or more quantum dot types imparted color changes to the microcrystalline glass across the entire wavelength range of 250nm-2500nm.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] In a first aspect, the present invention provides a quantum dot-based glass crystal, comprising glass crystal powder and quantum dots in a mass ratio of 2.5:1, wherein the glass crystal powder comprises the following components in mass percentage:

[0011] SiO2: 40-60%; H3BO3: 25-45%; La2O3: 1-3%; ZnO: 5-12%; Na2CO3: 10-20%;

[0012] The quantum dots are one or more combinations of tungsten oxide quantum dots, molybdenum oxide quantum dots, perovskite quantum dots, and graphene quantum dots.

[0013] In a first aspect, the present invention provides a method for preparing the above-mentioned quantum dot-based microcrystalline glass, comprising the following steps:

[0014] (1) Mix the raw materials evenly and place them in a crucible. The crucible may be a quartz crucible, a corundum crucible, or a platinum crucible;

[0015] (2) Melting is carried out using a muffle furnace with a heating rate of 8℃ / min, a melting temperature of 800-1200℃, and a melting time of 4-8h;

[0016] (3) Use a 10cm thick stainless steel plate as the base and place the stainless steel mold on the plate. After melting, pour the molten glass into the stainless steel mold placed in the air and let it cool and solidify;

[0017] (4) Place the formed glass in an annealing furnace at 200-500℃ for annealing for 1-3 hours, and cool it to room temperature with the furnace to obtain microcrystalline glass;

[0018] (5) Place the microcrystalline glass into a crusher and crush it into powder. The crushing time is 10-40 minutes, so that the particle size of the powder is between 50-200μ.

[0019] (6) Weigh the microcrystalline glass powder and quantum dots, mix them evenly after weighing, put them into a crucible, and melt them using a muffle furnace. The melting temperature is between Tg and Tf of the microcrystalline glass, and the melting time is 6-12 hours.

[0020] (7) Use a 10cm thick stainless steel plate as the base and place the stainless steel mold on the plate. After melting, pour the molten glass into the stainless steel mold placed in the air and let it cool and solidify;

[0021] (8) The formed glass is placed in a muffle furnace for annealing at a temperature of 240-600℃ for 2-6 hours. The glass is then cooled to room temperature in the furnace to obtain a quantum dot-coated glass-ceramic.

[0022] Compared with existing technologies, the present invention has the following advantages:

[0023] (1) Compared with the prior art, the advantages of the present invention are that the instruments and equipment used are simple, the operation is convenient, the product yield is higher, and the environmental pollution is basically zero. By first melting the microcrystalline glass and then combining the microcrystalline glass with the quantum dot material, the difficulty of directly melting the quantum dot microcrystalline glass can be reduced, the probability of melting failure can be reduced, and the influence of the nucleating agent on the nucleation and growth of crystals in the microcrystalline glass can be eliminated, so as to obtain pure microcrystalline glass; at the same time, the quantum dot material can be completely coated by the microcrystalline glass powder. By utilizing the stability of glass, the damp heat instability of quantum dots can be infinitely reduced and uniformly dispersed in the microcrystalline glass, thereby improving the weather resistance of the microcrystalline glass and increasing its service life.

[0024] (2) The glass of 10cm×5cm×0.5cm prepared by the present invention was measured by a barrier rate tester. Before the glass changed color, the ultraviolet and infrared barrier rates reached about 90%, and the visible light transmittance reached more than 80.0%. After the glass changed color, the ultraviolet barrier rate reached more than 99.0%, the infrared barrier rate was higher than 97%, and the visible light transmittance reached more than 30%. Attached Figure Description

[0025] Figure 1 shows the transmittance of the microcrystalline glass coated with tungsten oxide quantum dots prepared in Example 1 of the present invention before and after color change. Detailed Implementation

[0026] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0027] The invention will be described in detail below with reference to specific embodiments.

[0028] A quantum dot-based microcrystalline glass preparation method is described, with the following composition: SiO2: 40-60%, H3BO3: 25-45%, La2O3: 1-3%, ZnO: 4-12%, Na2CO3: 10-20%.

[0029] Quantum dots: one or more combinations of tungsten oxide quantum dots, molybdenum oxide quantum dots, perovskite quantum dots, and graphene quantum dots.

[0030] In the following examples, all raw materials used were of analytical grade.

[0031] Example 1

[0032] (1): Preparation of glass-ceramics:

[0033] Accurately weigh the following raw materials: SiO2: 48.4%, H3BO3: 32.7%, La2O3: 1.8%, ZnO: 4.8%, Na2CO3: 12.3%.

[0034] (2) Mix the raw materials evenly, put them into a corundum crucible, and use a muffle furnace for melting. The heating rate is 8℃ / min, the melting temperature is 860℃, and the melting time is 6.5h.

[0035] (3) Use a 10cm thick stainless steel plate as the base, and place a 10cm×5cm×0.5cm stainless steel mold on the plate. After melting, pour the molten glass into the stainless steel mold placed in the air and let it cool and solidify.

[0036] (4) The formed glass is placed in a muffle furnace at 450°C for annealing for 1.9 hours and then cooled to room temperature in the furnace to obtain microcrystalline glass.

[0037] (5) Place the microcrystalline glass into the crusher and crush it into powder. The crushing time is 25 minutes, so that the particle size of the powder is 185μm.

[0038] (6) Weigh 120g of microcrystalline glass powder and 48g of tungsten oxide quantum dots in a ratio of 2.5:1, mix them evenly, put them into a corundum crucible, and melt them in a muffle furnace at a temperature of 420℃ for 7.5h.

[0039] (7) Use a 10cm thick stainless steel plate as the base, and place a 10cm×5cm×0.5cm stainless steel mold on the plate. After melting, pour the molten glass into the stainless steel mold placed in the air and let it cool and solidify.

[0040] (8) The formed glass is placed in an annealing furnace for annealing at a temperature of 370°C for 4 hours. The glass is then cooled to room temperature in the furnace to obtain a microcrystalline glass coated with tungsten oxide quantum dots.

[0041] (9) Use a barrier rate tester to measure the ultraviolet barrier rate, infrared barrier rate, and visible light transmittance before the color change. Irradiate with an ultraviolet lamp for 1 minute, the glass color darkens, and measure the ultraviolet barrier rate, infrared barrier rate, and visible light transmittance after the color change.

[0042] Example 2

[0043] Modify step (6) of Example 1, weigh 120g of microcrystalline glass powder and 48g of quantum dots in a ratio of 2.5:1, and weigh 24g each of tungsten oxide quantum dots and molybdenum oxide quantum dots in a ratio of 1:1.

[0044] The remaining steps are the same as in Example 1.

[0045] Example 3

[0046] Modify step (6) of Example 1: Weigh 120g of microcrystalline glass powder and 48g of quantum dots in a ratio of 2.5:1. Weigh tungsten oxide quantum dots, molybdenum oxide quantum dots and perovskite quantum dots in a ratio of 3:4:1. Weigh 18g of tungsten oxide quantum dots, 24g of molybdenum oxide quantum dots and 6g of perovskite quantum dots.

[0047] The remaining steps are the same as in Example 1.

[0048] Example 4

[0049] Modify step (6) of Example 1: Weigh 120g of microcrystalline glass powder and 48g of quantum dots in a ratio of 2.5:1. Weigh tungsten oxide quantum dots, molybdenum oxide quantum dots, perovskite quantum dots and graphene quantum dots in a ratio of 1:3:2:1. Weigh 6.85g of tungsten oxide quantum dots, 20.57g of molybdenum oxide quantum dots, 13.7g of perovskite quantum dots and 6.85g of graphene quantum dots.

[0050] The remaining steps are the same as in Example 1.

[0051] Comparative Example 1

[0052] Change step (4) of Example 1, and change the annealing temperature to 400°C.

[0053] The remaining steps are the same as in Example 1.

[0054] Comparative Example 2

[0055] Change step (8) of Example 1, and change the annealing temperature to 400°C.

[0056] The remaining steps are the same as in Example 1.

[0057] Comparative Example 3

[0058] Change step (6) of Example 1, change the ratio of microcrystalline glass powder to quantum dots to 2:1, weigh 120g of microcrystalline glass powder and 60g of tungsten oxide quantum dots.

[0059] The remaining steps are the same as in Example 1.

[0060] Comparative Example 4

[0061] Change step (6) of Example 2, change the ratio of tungsten oxide quantum dots to molybdenum oxide quantum dots to 2:1, and weigh 32g of tungsten oxide and 16g of molybdenum oxide quantum dots.

[0062] The remaining steps are the same as in Example 2.

[0063] Comparative Example 5

[0064] Change step (6) of Example 3 and change step (6) of Example 1. Weigh 120g of microcrystalline glass powder and 48g of quantum dots in a ratio of 2.5:1. Weigh tungsten oxide quantum dots, molybdenum oxide quantum dots and perovskite quantum dots in a ratio of 1:2:1. Weigh 12g of tungsten oxide quantum dots, 24g of molybdenum oxide quantum dots and 12g of perovskite quantum dots.

[0065] The remaining steps are the same as in Example 3.

[0066] Comparative Example 6

[0067] Modify step (6) of Example 4, weigh 120g of microcrystalline glass powder and 48g of quantum dots in a ratio of 2.5:1, weigh tungsten oxide quantum dots, molybdenum oxide quantum dots, perovskite quantum dots and graphene quantum dots in a ratio of 2:2:3:1, weigh 12g of tungsten oxide quantum dots, 12g of molybdenum oxide quantum dots, 18g of perovskite quantum dots and 6g of graphene quantum dots.

[0068] The remaining steps are the same as in Example 4.

[0069] Comparative Example 7

[0070] Modify the steps of Example 1 (1) Accurately weigh the following raw materials: SiO2: 50%, H3BO3: 33%, La2O3: 1%, ZnO: 5%, Na2CO3: 11%.

[0071] The remaining steps are the same as in Example 1.

[0072] Comparative Example 8

[0073] The step (2) of Example 2 is changed, and the melting temperature is changed to 1000℃.

[0074] The step (4) of Example 2 was changed, and the annealing temperature was changed to 600°C.

[0075] The step (6) of Example 2 was changed, and the melting temperature was changed to 700°C.

[0076] The remaining steps are the same as in Example 2.

[0077] Table 1. Test results of Examples 1-4 and Comparative Examples 1-8

[0078]

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. 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 quantum dot-based microcrystalline glass, characterized in that: The microcrystalline glass powder and quantum dots are in a mass ratio of 2.5:

1. The mass percentage of each component in the microcrystalline glass powder is: SiO2: 48.4%, H3BO3: 32.7%, La2O3: 1.8%, ZnO: 4.8%, Na2CO3: 12.3%. The quantum dots are one or more combinations of tungsten oxide quantum dots, molybdenum oxide quantum dots, perovskite quantum dots, and graphene quantum dots. The preparation method of the quantum dot-based microcrystalline glass includes the following steps: (1) Mix the raw materials evenly and put them into a crucible, which is a quartz crucible, a corundum crucible, or a platinum crucible; (2) Melt using a muffle furnace, with a heating rate of 8℃ / min, a melting temperature of 800-1200℃, and a melting time of 4-8h; (3) Use a 10cm thick stainless steel plate as the base, place the stainless steel mold on the steel plate, and after melting, pour the molten glass into the stainless steel mold placed in the air. (4) Place the formed glass in an annealing furnace at 200-500℃ for 1-3 hours and cool it to room temperature with the furnace to obtain microcrystalline glass; (5) Place the microcrystalline glass in a crusher and crush it into powder for 10-40 minutes to make the powder particle size between 50-200μm; (6) Weigh the microcrystalline glass powder and quantum dots, mix them evenly after weighing, put them in a crucible, and melt them in a muffle furnace at a temperature between Tg-Tf of the microcrystalline glass for 6-12 hours; (7) Use a 10cm thick stainless steel plate as the base, place the stainless steel mold on the steel plate, pour the glass liquid into the stainless steel mold placed in the air after melting, and cool it to form; (8) Place the formed glass in a muffle furnace for annealing at a temperature of 240-600℃ for 2-6 hours and cool it to room temperature with the furnace to obtain microcrystalline glass coated with quantum dots.

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