Purple light excited red oxynitride glass ceramic as well as preparation method and application thereof

Abstract

The invention discloses purple light excited red oxynitride glass ceramic as well as a preparation method and application thereof, and belongs to the technical field of fluorescent glass ceramic. The crystal chemical general formula of the red-light oxynitride glass ceramic is Mg2Al4Si5 (ON) 18: Eu < 2 + >, the crystal structure belongs to a hexagonal crystal system, and the space group is P6 / mcc. According to the preparation method, the emission spectrum red shift of the Eu < 2 + > ion doped Mg2Al4Si5 (ON) 18 fluorescent material is induced through the regulation and control means of partial nitridation, the red light waveband coverage range is widened, the red light color purity is effectively improved, the preparation method of melting cooling and in-situ crystallization is adopted, the prepared material is an inorganic block material, the thermal stability and chemical stability of the material are improved, and the preparation method is suitable for industrial production. The material can be applied to the fields of white light LED devices, laser illumination display, plant illumination, optical medical treatment and the like.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent glass and ceramic technology, specifically relating to a violet light-excited red light oxynitride glass and ceramic, its preparation method, and its application. Background Technology

[0002] Phosphor-converting white light-emitting diodes (WLEDs), as a highly efficient and environmentally friendly core light source, have been widely used in lighting, display, and other fields. They offer advantages such as energy saving and long lifespan, making them a crucial pillar of the modern optoelectronic industry. With the increasing demands for light quality in lighting scenarios, the demand for high-quality WLEDs is growing. Against this backdrop, full-spectrum lighting solutions excited by violet light have demonstrated significant advantages, which also places higher demands on existing phosphor materials. Among these, a high color rendering index is one of the core indicators of high-quality WLED lighting, and the spectral contribution of the red light band is crucial for its achievement. However, existing red light materials generally suffer from drawbacks such as weak luminescence, easy efficiency decay, low color purity, severe reabsorption, low violet light excitation efficiency, and difficulty in synthesis. Therefore, the development of efficient red light components has become an urgent need to overcome the performance bottlenecks of high-quality WLEDs.

[0003] Currently, to address the demand for red light emission, Chinese patent CN117383830A discloses a high thermal conductivity, high strength red fluorescent glass-ceramic material and its preparation method. Its key feature is the control of mullite nanocrystal formation and growth in an amorphous glass phase to prepare a red fluorescent glass-ceramic with high thermal conductivity. This material has high crystallinity, effectively avoiding aging problems caused by epoxy resin, and its strongest emission peak is located near 615nm. However, its synthesis requires stringent high temperature and pressure conditions, and the optimal excitation band of the material is in the blue light region of 450~470nm, making it unsuitable for white LED devices that emit full spectrum of light when excited by violet LED chips. Chinese patent CN118908570B discloses a red-emitting borosilicate perovskite quantum dot glass and its preparation method. This invention induces the self-precipitation of perovskite quantum dots in an amorphous glass phase through mechanical ball milling, ultimately achieving multi-band red light emission from 637~651nm. The preparation process requires no annealing or heat treatment, making it simple, energy-efficient, and conducive to large-scale production. However, it should be noted that this material suffers from significant thermal instability; in a working environment of 120℃, its luminescence intensity drops to less than 10% of that at room temperature, severely limiting its practical application in production.

[0004] Mg2Al4Si5O with cordierite structural characteristics 18 It is an excellent luminescent matrix, and its unique (Al / Si)O4 six-membered ring structure can provide a light-emitting substrate for Eu. 2+Providing unique occupancy sites, it has been extensively studied by researchers. Hu Tao et al. published a study in 2021 entitled "Glass crystallization making red phosphor for high-power warm whitelighting," demonstrating the in-situ precipitation of Mg2Al4Si5O in MgO-Al2O3-SiO2 aluminosilicate glass. 18 Crystal phase, and Eu 2+ The activator is embedded in its six-coordinate pore sites, achieving a breakthrough in red light emission. The excitation peak of this fluorescent material covers the 300–500 nm wavelength range, allowing for efficient matching with commercially available violet or blue light chips, and it also possesses high quantum efficiency. However, it is limited by Mg2Al4Si5O... 18 Eu 2+ The emission peak of glass ceramics is located near 620nm, and its color coordinates fall in the orange-red light region of the CIE1931 color space. In LED packaging, it does not contribute enough to the spectrum of long-wavelength red light, resulting in a limited improvement in the color rendering index.

[0005] High-purity red light (typically deep red) can effectively improve this deficiency. Compared to orange-red light, deep red light not only has higher color purity but also a longer emission wavelength, enabling more precise matching of the object's reflectance spectrum characteristics and significantly improving the color rendering performance of the lighting system. It also avoids color distortion caused by spectral overlap. Partial nitriding, as an efficient control method, can induce a redshift in the spectrum of phosphors or luminescent materials, thereby broadening the red light band coverage and providing key technical support for the packaging and application of high color rendering index LED devices. Therefore, this research involves a novel deep red glass-ceramic excited by violet light, maintaining high stability while simultaneously achieving high-purity red light emission. This has significant practical value for the research and fabrication of high-quality violet-excited full-spectrum LED devices. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention discloses a violet-excited red-light oxynitride glass-ceramic, which induces Eu through partial nitridation modulation. 2+ Ion-doped Mg2Al4Si5(ON) 18 The emission spectrum of the fluorescent material is red-shifted, which broadens the coverage of the red light band and effectively improves the purity of the red light. Furthermore, the material is prepared by a "melt cooling + in-situ crystallization" method, which produces an inorganic bulk material, thereby improving the material's thermal and chemical stability.

[0007] To achieve the purpose of the invention, the present invention provides the following technical solution: This invention discloses a violet-excited red-light oxynitride glass-ceramic, wherein the general chemical formula of the red-light oxynitride glass-ceramic is Mg2Al4Si5(ON).18 Eu 2+ Its crystal structure belongs to the hexagonal crystal system, and its space group is [missing information]. P 6 / mcc .

[0008] Furthermore, the purple light-excited red light oxynitride glass-ceramic emits light with a wavelength of 500-800 nm, a main peak at 620-650 nm, and a quantum yield of >60%.

[0009] This invention also discloses a method for preparing violet-excited red-light oxynitride glass-ceramics, comprising the following steps: S1. Weigh out SiO2, Al2O3, MgO, Eu2O3, Si3N4, AlN, Mg3N2 and EuN respectively, grind them thoroughly and transfer them to a crucible; S2. Place the mixed raw materials from S1 in a high-temperature furnace and heat them to melt. Pour the melted raw materials into a preheated mold to obtain the precursor glass. S3. The precursor glass obtained in S2 is heat-treated to obtain red oxynitride glass ceramic.

[0010] Furthermore, the mole fractions of each component in the raw material S1 are as follows: 30~60 mol% SiO2, 20~50 mol% Al2O3, 20~50 mol% MgO, 0.005~5 mol% Eu2O3, 0.001~20 mol% Si3N4, 0.001~20 mol% AlN, 0.001~10 mol% Mg3N2, and 0.001~5 mol% EuN.

[0011] Furthermore, the crucible in S1 is any one of an alumina crucible, a graphite crucible, or a boron nitride crucible.

[0012] Furthermore, the heating and melting conditions in S2 are: heating at 1400-1700℃ for 10-360 min.

[0013] Furthermore, the heat treatment of S3 is carried out under a specific atmosphere; the specific atmosphere is one or a combination of two or more of H2, CO, carbon powder, N2, NH3, and air.

[0014] Furthermore, the heat treatment conditions in S3 are: heating at 1000-1300℃ for 10-480 min.

[0015] Furthermore, the heating and melting process in S2 and the heat treatment process in S3 are carried out in a tubular reduction furnace, a box-type muffle furnace, or a lifting furnace.

[0016] The present invention also discloses the application of a violet light-excited red oxynitride glass ceramic, which can be applied in the fields of white LED, laser lighting display, plant lighting, and optical medical.

[0017] Furthermore, using violet LED chips or LD light-emitting diodes with emission wavelengths of 380-420nm as excitation light sources and red oxynitride glass ceramics as light-emitting components, the light absorbs violet light energy, undergoes transitions, and releases multi-band red light, which can be integrated into different functional devices; violet and white light can form basic white light to prepare LED white light devices; the output red light, blue light, and green light laser modules can be combined to form RGB three primary colors, which can be used in display devices; red light can also be used by plant chlorophyll to synthesize substances needed for growth; and it can also be used in the preparation of medical devices.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention discloses for the first time a novel violet-excited red-light oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2 + It is a novel red fluorescent material with a novel chemical composition. This design cleverly induces Eu through partial nitridation regulation. 2+ Ion-doped Mg2Al4Si5(ON) 18 The emission spectrum of fluorescent materials red-shifts, and is related to Mg2Al4Si5O 18 Eu 2+ In comparison, O 2- (Ionic radius ~1.40 Å) by N 3- (~1.46Å) substitution, coordination environment distortion, Eu 2+ The increased 5d orbital splitting energy of the activating ions and the decreased 5d→4f transition energy difference result in a redshift of the emission wavelength, enabling tunable emission within the 620nm-650nm range. This broadens the red light band coverage and effectively improves the red light color purity, making it suitable for various lighting systems. Furthermore, by precisely adjusting the glass composition and optimizing the crystal structure, the intensity of the excitation spectrum in the longer wavelength band is reduced, effectively minimizing the occurrence of significant reabsorption effects. This provides a novel material design approach to overcome the challenge of developing deep-red light-excited materials using violet light.

[0019] 2. The red-light oxynitride glass-ceramic Mg2Al4Si5(ON) disclosed in this invention 18 Eu 2+ It exhibits superior overall performance, with its most significant advantage being its highly efficient violet-excited red light emission characteristics: under 420nm violet light excitation, it can generate broadband red light emission covering 550-800nm, with the main peak of maximum wavelength emission precisely located at 650nm, approaching that of commercial CaAlSiN3:Eu. 2+The deep red phosphor exhibits an emission peak with a full width at half maximum (FWHM) of 132 nm and a groundbreaking quantum efficiency exceeding 60%, far surpassing the performance of many existing red materials under violet light excitation. Secondly, the introduction of nitrogen atoms alters the glass network structure, enhancing network polymerization and bonding strength, resulting in excellent thermal stability. Its luminescence intensity retention is significantly improved at high temperatures, ensuring the reliability of the device during long-term operation. Furthermore, the microcrystalline glass itself possesses high mechanical strength, excellent physicochemical stability, and optical uniformity.

[0020] 3. The red-light oxynitride glass-ceramic disclosed in this invention has an excitation range centered at 420nm that matches the current commercial violet LED / LD chips with emission wavelengths between 380-420nm. It can efficiently convert violet photons into the desired red light, effectively solving the core problem of insufficient excitation efficiency of violet-excited red light materials. Furthermore, the broadband red light emission of 550-800nm ​​provides a high-quality red light foundation for constructing continuous and complete full-spectrum white light, helping to fill key wavelength bands and significantly improving the color rendering index of the light source. R a Color fidelity R f Color gamut coverage R g And spectral matching degree.

[0021] 4. The red oxynitride glass-ceramic prepared by the method of this invention is an inorganic bulk material with good thermal and chemical stability. It can effectively solve the problems of thermal quenching and aging faced by powder phosphor materials in resin / silicone encapsulation, significantly extend the life of LED devices and maintain the luminous efficacy temperature. The "melt cooling + in-situ crystallization" preparation process is simple and has low raw material cost. Compared with the complex process that requires pre-synthesizing phosphors and then co-sintering them with glass powder, it significantly reduces energy consumption and production costs, and is more conducive to large-scale production. It provides strong material support for the popularization of high-performance, healthy and safe violet-excited full-spectrum LED devices. Attached Figure Description

[0022] Figure 1 The precursor glass and Mg2Al4Si5(ON) prepared in Example 1 of this invention. 18 Eu 2+ X-ray diffraction pattern of red oxynitride glass ceramics; Figure 2 The Mg2Al4Si5(ON) prepared in Examples 2-5 of this invention. 18 Eu 2+ Normalized emission spectrum of red oxynitride glass ceramics; Figure 3 The Mg2Al4Si5(ON) prepared in Examples 2-5 of this invention.18 Eu 2+ Normalized excitation spectrum of red-light oxynitride glass ceramics; Figure 4 The Mg2Al4Si5(ON) prepared in Example 5 of this invention. 18 Eu 2+ Red-light oxynitride glass ceramics and CaAlSiN3:Eu 2+ Normalized excitation and emission spectra of commercial red powder; Figure 5 The Mg2Al4Si5(ON) prepared in Examples 6-9 of this invention. 18 Eu 2+ Temperature-dependent emission performance of red oxynitride glass ceramics. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Unless otherwise specified, all raw materials used in the following examples were purchased commercially.

[0025] Unless otherwise specified, the methods used in the following embodiments are conventional operating methods in the art.

[0026] Example 1 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ Its preparation method includes the following steps: S1. Weigh the following components: 40 mol% SiO2, 25 mol% Al2O3, 20 mol% MgO, 0.3 mol% Eu2O3, 10 mol% Si3N4, 4 mol% AlN, 0.5 mol% Mg3N2, and 0.2 mol% EuN. Grind for 1 hour and then transfer to an alumina crucible. S2. Place the raw material ground in S1 into a box-type muffle furnace and heat it at 1550℃ for 240 minutes in an air atmosphere to obtain glass melt. Pour it into a preheated copper mold to obtain precursor glass. S3. The precursor glass obtained in S2 is placed in a box-type muffle furnace and heat-treated at 1200℃ for 480 min in air atmosphere to obtain Mg2Al4Si5(ON). 18 Eu2+ Red light glass ceramic.

[0027] The precursor glass and ultraviolet-excited Mg2Al4Si5(ON) prepared in this embodiment 18 Eu 2+ X-ray diffraction pattern of red oxynitride glass ceramics as shown in the figure. Figure 1 As shown, the X-ray diffraction data of the prepared microcrystalline glass is consistent with the information on the standard card, indicating that the present invention has successfully precipitated Mg2Al4Si5(ON). 18 Crystal phase.

[0028] Example 2 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ Its preparation method includes the following steps: S1. Weigh the following components: 40 mol% SiO2, 25 mol% Al2O3, 20 mol% MgO, 0.3 mol% Eu2O3, 4 mol% AlN, 0.5 mol% Mg3N2, and 0.2 mol% EuN. Grind them thoroughly for 1 hour and then transfer them to an alumina crucible. S2. Place the raw material ground in S1 into a box-type muffle furnace and heat it at 1600℃ for 240 minutes in an air atmosphere to obtain glass melt. Then pour it into a preheated copper mold to obtain precursor glass. S3. The precursor glass obtained in step S2 is placed in a tube reduction furnace and heat-treated at 1250℃ for 480 min under a H2 reducing atmosphere to obtain Mg2Al4Si5(ON). 18 Eu 2+ Red light glass ceramic.

[0029] Example 3 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ The difference between this embodiment and embodiment 2 is that 2 mol% Si3N4 is added to the raw materials in S1.

[0030] Example 4 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ The difference between this embodiment and embodiment 2 is that 6 mol% Si3N4 is added to the raw materials in S1.

[0031] Example 5 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ The difference between this embodiment and embodiment 2 is that 10 mol% Si3N4 is added to the raw materials in S1.

[0032] Example 6 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ Its preparation method includes the following steps: S1. Weigh the following components: 40 mol% SiO2, 25 mol% Al2O3, 20 mol% MgO, 0.3 mol% Eu2O3, 4 mol% AlN, 0.5 mol% Mg3N2, and 0.2 mol% EuN. Grind thoroughly for 1 hour and then transfer to an alumina crucible. S2. Place the raw material ground in S1 into a tube reduction furnace and heat it at 1600℃ for 240 minutes under a H2 reducing atmosphere to obtain glass melt, which is then poured into a preheated copper mold to obtain precursor glass. S3. The precursor glass obtained in step S2 is placed in a tube reduction furnace and heat-treated at 1250℃ for 480 min under a H2 reducing atmosphere to obtain Mg2Al4Si5(ON). 18 Eu 2+ Red light glass ceramic.

[0033] Example 7 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ The difference between this embodiment and embodiment 6 is that 2 mol% Si3N4 is added to the raw materials in S1.

[0034] Example 8 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ The difference between this embodiment and embodiment 6 is that 6 mol% Si3N4 is added to the raw materials in S1.

[0035] Example 9 This embodiment provides a violet-excited red-light-emitting oxynitride glass-ceramic Mg2Al4Si5(ON). 18 Eu 2+ The difference between this embodiment and embodiment 6 is that 10 mol% Si3N4 is added to the raw materials in S1.

[0036] Performance Characterization The red-light oxynitride glass ceramics prepared in Examples 2-9 were analyzed and tested accordingly, and the specific results are as follows: Figure 2 The Mg2Al4Si5(ON) prepared in Examples 2-5 of this invention. 18 Eu 2+ The normalized emission spectra of red-light glass ceramics at different nitrogen doping concentrations are shown in the figure. Under the excitation of a 420nm violet light source, the emission spectrum of the fluorescent glass ceramics covers a wide range of 550~800nm. The peak value gradually redshifts from 620nm to 650nm, the full width at half maximum (FWHM) expands, and the color purity is improved.

[0037] Figure 3 The Mg2Al4Si5(ON) prepared in Examples 2-5 of this invention. 18 Eu 2+ The normalized excitation spectra of red-light glass-ceramics at different nitrogen doping concentrations are shown in the figure, Mg2Al4Si5(ON). 18 Eu 2+ The excitation peak of the glass ceramic has a main peak around 420nm, which is highly compatible with commercial violet chips.

[0038] Figure 4 The Mg2Al4Si5(ON) prepared in Example 5 is shown. 18 Eu 2+ Red-light glass ceramics and CaAlSiN3:Eu 2+ The normalized excitation and emission spectra of commercial red pigments are shown in the figure. The Mg2Al4Si5(ON) prepared in Example 5 was measured using a FLS1000 fluorescence spectrometer. 18 Eu 2+ The excitation spectral intensity of glass ceramics in the long-wavelength region is significantly lower than that of CaAlSiN3:Eu. 2+ Commercial red powder effectively reduces reabsorption and contains Mg2Al4Si5(ON). 18 Eu 2+ Glass-ceramics have a larger half-width at half-maximum, which is more conducive to the construction of full-spectrum emission.

[0039] Figure 5 The Mg2Al4Si5(ON) prepared in Examples 6-9. 18 Eu 2+ Temperature-dependent emission performance of red-light glass-ceramics at different nitrogen doping concentrations, as shown in the figure. Figure 5 As shown, with the increase of nitriding degree, the thermal stability of fluorescent glass ceramics gradually increases, and the emission intensity at 150℃ remains more than 95% of the intensity at room temperature.

[0040] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A violet-light-excited red-light-emitting oxynitride glass-ceramic, characterized in that: The general chemical formula of the red-light oxynitride glass-ceramic is Mg2Al4Si5(ON). 18 Eu 2+ Its crystal structure belongs to the hexagonal crystal system, and its space group is P6 / mcc.

2. A method for preparing a violet-excited red-light oxynitride glass-ceramic as described in claim 1, characterized in that: S1. Weigh out SiO2, Al2O3, MgO, Eu2O3, Si3N4, AlN, Mg3N2, and EuN, grind them thoroughly, and then transfer them to a crucible. S2. Heat and melt the mixed powder after grinding in S1, and pour it into a preheated mold to obtain the precursor glass; S3. The precursor glass obtained in S2 is subjected to heat treatment to obtain the red oxynitride glass ceramic.

3. The preparation method according to claim 2, characterized in that: The molar percentages of each raw material in S1 are as follows: 30~60 mol% SiO2, 20~50 mol% Al2O3, 20~50 mol% MgO, 0.005~5 mol% Eu2O3, 0.001~20 mol% Si3N4, 0.001~20 mol% AlN, 0.001~10 mol% Mg3N2, and 0.001~5 mol% EuN.

4. The preparation method according to claim 2, characterized in that: The conditions for heating and melting in S2 are: heating at 1400-1700℃ for 10-360 min.

5. The preparation method according to claim 2, characterized in that: The heat treatment in S3 is carried out under a specific atmosphere; the specific atmosphere is one or a combination of two or more of H2, CO, carbon powder, N2, NH3 or air.

6. The preparation method according to claim 2, characterized in that: The heat treatment conditions in S3 are: heating at 1000-1300℃ for 10-480 min.

7. The purple light-excited red light oxynitride glass ceramic as described in claim 1 is applied in the fields of white LED, laser lighting display, plant lighting, and optical medical.

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