Fluorescent micro-ceramic glass with adjustable afterglow luminescence color and preparation method thereof

Abstract

The present invention discloses a fluorescent glass-ceramic with adjustable afterglow luminescence color and a preparation method thereof, belonging to the technical field of inorganic luminescent materials. The fluorescent glass-ceramic with continuously adjustable afterglow luminescence color of the present invention comprises, by molar proportions, 45-70 parts of GeO2, 5-15 parts of Al2O3, 10-25 parts of ZnO, 5-20 parts of Li2CO3, and 0.5 parts of MnCO3. The preparation method of the fluorescent glass-ceramic with continuously adjustable afterglow luminescence color from green to red disclosed by the present invention is simple and low in cost. The material has excellent physical and chemical stability, can effectively avoid unnecessary energy transfer between different activated ions, is conducive to improving luminous efficiency, and has good application prospects in fields such as color display and optical anti-counterfeiting.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic luminescent materials, and in particular to fluorescent microcrystalline glass with adjustable afterglow luminescence color and a preparation method thereof. Background Art

[0002] Inorganic multi-color luminescent materials refer to materials that emit different colors of light under different excitation conditions, and have potential application prospects in the fields of color information display, optical anti-counterfeiting, etc. Common luminescence centers of inorganic multi-color luminescent materials include rare earth ions, transition metal ions, defects, etc. Since rare earth elements are non-renewable resources, how to develop rare earth-free doped luminescent materials has become a current research hotspot. Transition metal ions are sensitive to the crystal field environment in which they are located, and their luminescence color can be changed by adjusting the coordination environment of the transition metal ions. Most transition metal ion-doped multi-color luminescent materials often require mechanical mixing of multiple materials with different luminescence colors, and it is difficult to obtain continuously adjustable luminescence colors in a single matrix.

[0003] Long afterglow luminescent materials refer to materials that can continue to emit light after the excitation light source is turned off. In recent years, long afterglow luminescent materials have been widely used in fields such as information storage and energy-saving lighting. However, for a specific long afterglow luminescent material, the afterglow color is fixed, and the afterglow color cannot be dynamically adjusted by changing the excitation conditions. In order to obtain a color-adjustable long afterglow luminescent material, it is necessary to mechanically mix long afterglow luminescent materials of multiple luminescent colors. However, different luminescent materials often have different physical and chemical properties, which leads to uneven physical and chemical properties of the mixture, thereby limiting its service life and application scenarios. Therefore, obtaining a long afterglow luminescent material with continuously adjustable afterglow luminescence in a single matrix through component and structure regulation is of great significance for expanding the application scenarios of long afterglow luminescent materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a fluorescent glass-ceramic with adjustable afterglow luminescence color and a preparation method thereof to address the above-mentioned problems in the background art. The preparation method of the fluorescent glass-ceramic with continuously adjustable afterglow luminescence color from green to red disclosed in the present invention is simple and low-cost. The material has excellent physical and chemical stability, can effectively avoid unnecessary energy transfer between different activated ions, and is conducive to improving luminous efficiency. It has good application prospects in fields such as color display and optical anti-counterfeiting.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a fluorescent glass-ceramic with continuously adjustable afterglow luminescence color, wherein the raw materials, measured by mole parts, include:

[0007] GeO2 45-70 parts, Al2O3 5-15 parts, ZnO 10-25 parts, Li2CO3 5-20 parts and MnCO3 0.5 parts.

[0008] Preferably, the doping amount of MnCO3 is 0.5 mol%, based on the total molar amount of GeO2, Al2O3, ZnO, and Li2CO3 being 100%.

[0009] The second technical solution of the present invention is to provide a method for preparing the fluorescent glass-ceramics with continuously adjustable afterglow luminescence color, comprising the following steps:

[0010] The raw materials are mixed, melted, formed, annealed, and heat-treated to obtain the fluorescent micro-ceramic glass with continuously adjustable afterglow luminescence color.

[0011] Preferably, the smelting temperature is 1350-1550° C., and the smelting time is 30-60 minutes.

[0012] Preferably, the forming process comprises the following steps:

[0013] The molten glass obtained after the melting operation is poured into a mold, and another mold is used to press-cast the molten glass into bulk glass.

[0014] Preferably, the mold is preheated to 300° C. before use.

[0015] Preferably, the annealing is performed at 450-500° C. for 2-4 hours.

[0016] Preferably, the heat treatment temperature is 580-700° C., and the time is 1.5-4 hours.

[0017] The beneficial technical effects of the present invention are as follows:

[0018] The present invention selects transition metal ions Mn 2+ ions as luminescence centers. The precursor glass without heat treatment is amorphous, and the doped Mn 2+ The coordination number is 6, and its luminescent color is red light at 640 nanometers. Through controlled crystallization by heat treatment, cubic ZnAl2O4 nanocrystals with spinel structure can be precipitated. After crystallization, Mn 2+ Can replace the Zn at the center of the tetrahedron 2+ Entering into ZnAl2O4 nanocrystal, the coordination number becomes 4, and the luminous color changes to 532 nm green light. The present invention controls the crystallinity of the microcrystalline glass by controlling the heat treatment process, so that the prepared glass is in a state of not completely crystallizing, thereby making the two Mn with different coordination numbers 2+ ions exist at the same time, the doped Mn 2+Part of it is in the six-coordinated glass network, and the rest is in the four-coordinated ZnAl2O4 nanocrystals. 2+ The luminescence color and the optimal excitation wavelength are different, resulting in the change of the luminescence intensity ratio of red and green light under different wavelengths of excitation. Therefore, by adjusting the relative intensity of red and green light, a continuously adjustable luminescence color from green to red can be obtained. On this basis, due to the presence of a large number of defects in the matrix material, the defects can effectively capture electrons and transfer them to Mn 2+ , so after the excitation source is turned off, the glass still has a continuously adjustable afterglow from green to red.

[0019] The present invention can achieve continuously adjustable luminescence colors from green to red by varying the excitation wavelength of a single glass-ceramic sample. Accordingly, because different wavelengths of excitation light can fill different defect energy levels, the luminescence color remains continuously adjustable from green to red even after the excitation light source is turned off.

[0020] In the present invention, GeO2 is a glass network forming oxide, Al2O3 is a glass network intermediate oxide, ZnO and Li2CO3 are network outer oxides, and Mn 2+ It is the luminescent central ion and is introduced into the glass component in the form of MnCO3.

[0021] The preparation method of the fluorescent microcrystalline glass with continuously adjustable afterglow luminescence color from green to red disclosed in the present invention is simple and low-cost. The material has excellent physical and chemical stability, can effectively avoid unnecessary energy transfer between different activated ions, is conducive to improving luminescence efficiency, and has good application prospects in fields such as color display and optical anti-counterfeiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is the XRD pattern of the product of Example 1.

[0024] Figure 2 is the emission spectrum of the precursor glass in Example 1.

[0025] Figure 3 This is the afterglow spectrum of the precursor glass in Example 1.

[0026] Figure 4The emission spectra of the product of Example 1 under ultraviolet light excitation of different wavelengths.

[0027] Figure 5 The afterglow spectra of the product of Example 1 after being excited by ultraviolet light of different wavelengths.

[0028] Figure 6 The color coordinate diagram corresponding to the afterglow spectrum of the product of Example 1 after being excited by ultraviolet light of different wavelengths.

[0029] Figure 7 These are the excitation spectra corresponding to the red light and green light in the product of Example 1. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0031] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0033] The terms “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0034] The raw materials used in the following examples and comparative examples of the present invention are all commercially available products.

[0035] Example 1

[0036] The fluorescent glass-ceramic with continuously adjustable afterglow luminescence color is composed of the following raw materials in molar fractions:

[0037] 60 parts of GeO2, 10 parts of Al2O3, 20 parts of ZnO, 10 parts of Li2CO3 and 0.5 parts of MnCO3.

[0038] Preparation of fluorescent glass-ceramics with continuously adjustable afterglow luminescence color:

[0039] The starting materials are GeO2, Al2O3, ZnO, Li2CO3, and MnCO3 powders with a purity of ≥99.99%. These powders are mixed in the appropriate proportions and then weighed out to 20g in an agate mortar for thorough grinding and mixing. The resulting mixture is poured into an alumina crucible and then melted in a 1450°C high-temperature silicon-molybdenum rod lift furnace for 40 minutes. The molten glass is then quickly poured onto a stainless steel plate preheated to 300°C and pressed into a solid glass using another preheated 300°C stainless steel plate. The glass is then quickly transferred to a 450°C muffle furnace for annealing for 2 hours. After cooling naturally to room temperature, the precursor glass is obtained. Finally, the annealed precursor glass is kept in a muffle furnace at 580°C for 2 hours to produce fluorescent glass-ceramics with continuously adjustable afterglow color.

[0040] Figure 1 This is the XRD pattern of the product of Example 1.

[0041] like Figure 1 As shown in Figure 3, after heat treatment, the diffraction peaks in the XRD pattern correspond to the spinel structure of ZnAl2O4, indicating that ZnAl2O4 nanocrystals are successfully precipitated in the glass matrix.

[0042] Effect verification

[0043] (1) The precursor glass in Example 1 was excited with 320nm ultraviolet light, and the emission spectrum and afterglow spectrum were tested. The test results are as follows: Figure 2-3 shown.

[0044] Figure 2 is the emission spectrum of the precursor glass in Example 1.

[0045] Figure 3 This is the afterglow spectrum of the precursor glass in Example 1.

[0046] like Figure 2-3 As shown, in the precursor glass, Mn 2+ The coordination number is 6, so red light with a peak at 640 nanometers is obtained under ultraviolet light excitation; due to defects in the glass, after the ultraviolet light is turned off, the glass sample has a red afterglow.

[0047] (2) The product of Example 1 was excited with light of different wavelengths, and the emission spectrum, afterglow spectrum and the color coordinate diagram corresponding to the afterglow spectrum were tested. The test results are shown in FIG. Figure 4 shown.

[0048] Figure 4 The emission spectra of the product of Example 1 under ultraviolet light excitation of different wavelengths.

[0049] Figure 5The afterglow spectra of the product of Example 1 after being excited by ultraviolet light of different wavelengths.

[0050] Figure 6 The color coordinate diagram corresponding to the afterglow spectrum of the product of Example 1 after being excited by ultraviolet light of different wavelengths.

[0051] like Figure 4 As shown in the figure, under ultraviolet light excitation, the emission spectrum of the glass-ceramic sample consists of two emission bands, red and green, with the central wavelengths of the two emission bands being 640nm and 532nm respectively, indicating that there are two coordination numbers of Mn in this glass-ceramic. 2+ .

[0052] like Figure 5 As shown in Figure 2, as the excitation wavelength increases, the red-green intensity ratio of the afterglow luminescence gradually increases.

[0053] like Figure 6 As shown, the CIE color coordinates of the afterglow spectrum gradually change from (0.3727, 0.5849) to (0.5686, 0.4218), indicating that the glass-ceramic has a continuously adjustable afterglow luminescence color from green to red.

[0054] (3) Figure 4 The central wavelengths of the red and green emission bands in the image are used as monitoring wavelengths to test the excitation spectrum of the product of Example 1. The test results are as follows: Figure 7 shown.

[0055] Figure 7 These are the excitation spectra corresponding to the red light and green light in the product of Example 1.

[0056] like Figure 7 As shown, the excitation spectra of the two emission bands are very different, resulting in different intensity ratios of the red and green emission bands under ultraviolet light excitation of different wavelengths, ultimately obtaining a continuously adjustable luminescence color from green to red.

[0057] Example 2

[0058] The fluorescent glass-ceramic with continuously adjustable afterglow luminescence color is composed of the following raw materials in molar fractions:

[0059] 250 parts of GeO, 15 parts of Al2O3, 25 parts of ZnO, 10 parts of Li2CO3 and 0.5 parts of MnCO3.

[0060] Preparation of fluorescent glass-ceramics with continuously adjustable afterglow luminescence color:

[0061] The initial raw materials are GeO2, Al2O3, ZnO, Li2CO3, and MnCO3 powders with a purity of ≥99.99%. These powders are mixed in the appropriate proportions. 20g of the raw materials are weighed and thoroughly ground in an agate mortar. The resulting mixture is poured into an alumina crucible and then melted in a 1500°C high-temperature silicon-molybdenum rod lift furnace for 30 minutes. The molten glass is then quickly poured onto a stainless steel plate preheated to 300°C and pressed into a solid glass using another preheated 300°C stainless steel plate. The glass is then quickly annealed in a 480°C muffle furnace for 2 hours. After cooling naturally to room temperature, the precursor glass is obtained. Finally, the annealed precursor glass is kept in the muffle furnace at 620°C for 2 hours to produce fluorescent glass-ceramics with continuously adjustable afterglow color.

[0062] Example 3

[0063] The fluorescent glass-ceramic with continuously adjustable afterglow luminescence color is composed of the following raw materials in molar fractions:

[0064] GeO245 parts, Al2O315 parts, ZnO 20 parts, Li2CO320 parts and MnCO30.5 parts.

[0065] Preparation of fluorescent glass-ceramics with continuously adjustable afterglow luminescence color:

[0066] The initial raw materials are GeO2, Al2O3, ZnO, Li2CO3, and MnCO3 powders with a purity of ≥99.99%. These powders are mixed in the appropriate proportions and then weighed out to 20g in an agate mortar for thorough grinding and mixing. The resulting mixture is poured into an alumina crucible and then melted in a 1400°C high-temperature silicon-molybdenum rod lift furnace for 45 minutes. The molten glass is then quickly poured onto a stainless steel plate preheated to 300°C and pressed into a solid glass using another preheated 300°C stainless steel plate. The glass is then quickly transferred to a 500°C muffle furnace for annealing for 3 hours. After cooling naturally to room temperature, the precursor glass is obtained. Finally, the annealed precursor glass is kept in the muffle furnace at 660°C for 2 hours to produce fluorescent glass-ceramics with continuously adjustable afterglow color.

[0067] Example 4

[0068] The fluorescent glass-ceramic with continuously adjustable afterglow luminescence color is composed of the following raw materials in molar fractions:

[0069] GeO255 parts, Al2O315 parts, ZnO 15 parts, Li2CO315 parts and MnCO30.5 parts.

[0070] Preparation of fluorescent glass-ceramics with continuously adjustable afterglow luminescence color:

[0071] The initial raw materials are GeO2, Al2O3, ZnO, Li2CO3, and MnCO3 powders with a purity of ≥99.99%. These powders are mixed in the appropriate proportions and then weighed out to 20g in an agate mortar for thorough grinding and mixing. The resulting mixture is poured into an alumina crucible and then melted in a 1350°C high-temperature silicon-molybdenum rod lift furnace for 60 minutes. The molten glass is then quickly poured onto a stainless steel plate preheated to 300°C and pressed into a solid glass using another preheated 300°C stainless steel plate. The glass is then quickly transferred to a 450°C muffle furnace for annealing for 2 hours. After cooling naturally to room temperature, the precursor glass is obtained. Finally, the annealed precursor glass is kept in the muffle furnace at 680°C for 2 hours to produce fluorescent glass-ceramics with continuously adjustable afterglow color.

[0072] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A fluorescent glass-ceramic with continuously adjustable afterglow luminescence color, characterized in that: The raw materials, in parts by mole, include: GeO2 45-70 parts, Al2O3 5-15 parts, ZnO 10-25 parts, Li2CO3 5-20 parts and MnCO3 0.5 parts.

2. A method for preparing the fluorescent glass-ceramics with continuously adjustable afterglow luminescence color according to claim 1, characterized in that: The following steps are involved: The raw materials are mixed, melted, formed, annealed, and heat-treated to obtain the fluorescent micro-ceramic glass with continuously adjustable afterglow luminescence color.

3. The preparation method according to claim 2, characterized in that The smelting temperature is 1350-1550° C., and the smelting time is 30-60 minutes.

4. The preparation method according to claim 2, characterized in that The molding process comprises the following steps: The molten glass obtained after the melting operation is poured into a mold, and another mold is used to press-cast the molten glass into bulk glass.

5. The preparation method according to claim 4, characterized in that The mold was preheated to 300° C. before use.

6. The preparation method according to claim 2, characterized in that The annealing is performed at 450-500° C. for 2-4 hours.

7. The preparation method according to claim 2, characterized in that The heat treatment temperature is 580-700° C., and the time is 1.5-4 hours.

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