Efficient fluorescence conversion glass based on nitride red fluorescent powder compounded binary germanium phosphorus glass and preparation method of efficient fluorescence conversion glass

Abstract

The invention discloses high-efficiency fluorescence conversion glass based on nitride red fluorescent powder composite binary germanium-phosphorus glass and a preparation method thereof, the high-efficiency fluorescence conversion glass is successfully prepared by taking binary germanium-phosphorus glass with specific components as a substrate and red nitride fluorescent powder as a luminescent material through low-temperature rapid sintering by a spark plasma sintering (SPS) technology. The fluorescent glass comprises the following raw materials: nitride red fluorescent powder and precursor glass powder, the precursor glass powder is prepared from the following raw materials in percentage by mole: 26 to 48 mol percent of GeO2 and 52 to 74 mol percent of P2O5, and the mass of the nitride red fluorescent powder is 1 to 7 percent of the mass of the total powder. Through a specific preparation process, the high-efficiency luminescence property, excellent thermal stability and high laser irradiation threshold value of the fluorescent glass are realized, and the high-performance requirement of laser illumination is met. Meanwhile, the preparation method is simple in preparation process, green, environment-friendly and low in production cost, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of laser lighting, and relates to a nitride red fluorescent glass and a preparation method thereof, and specifically relates to a high-efficiency fluorescent conversion glass based on nitride red fluorescent powder composite binary germanium phosphorus glass and a preparation method thereof. Background Art

[0002] Laser-driven lighting is regarded as the next generation of high-brightness lighting technology due to its high power density, long irradiation distance and low beam divergence. However, in the actual application of laser lighting, color converters are prone to heat accumulation under high-power density laser excitation, resulting in luminescence quenching and reduced device brightness. In order to solve this problem, new fluorescent conversion materials have been developed and studied. Fluorescent glass has become an ideal color conversion material for laser lighting due to its diverse matrix components, simple preparation process, easy adjustment of phosphor content and low sintering temperature. In particular, red fluorescent glass materials that emit deep red light are particularly popular in the fields of solid-state lighting, medical imaging and plant supplementary lighting. However, it is difficult to prepare efficient red fluorescent glass, mainly because nitride red phosphors have poor stability and are easily decomposed at high temperatures. In addition, nitride red phosphors are prone to corrosion when heated together with glass melts, resulting in a decrease in luminescence performance and mechanical properties.

[0003] As an advanced solid-phase sintering technology, SPS can achieve complete densification of glass materials at low temperature and in a short time, providing a new way to solve the above problems. In previous studies, we used SPS technology to prepare high-efficiency red fluorescent glass. However, the laser damage threshold of the glass matrix (borosilicate glass matrix) used was low, making it difficult to apply to high-power laser illumination.

[0004] Therefore, finding a glass matrix with a high laser damage threshold and preparing high-efficiency nitride red fluorescent glass with excellent interface morphology and excellent luminescence performance are technical problems that need to be urgently solved in the field of laser lighting. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a high-efficiency fluorescent conversion glass based on binary glass containing only glass formers doped with nitride red phosphors and prepared by SPS technology. The purpose is to solve the problems of low laser damage threshold of the glass matrix used in preparing fluorescent glass and serious interface reaction between the glass matrix and the nitride red phosphor.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A high-efficiency fluorescent conversion glass based on nitride red fluorescent powder composite binary germanium phosphorus glass, the raw materials of which include the following components:

[0008] Nitride red phosphor and precursor glass powder; the precursor glass powder is a binary glass matrix powder containing only glass formers and does not contain alkali metals and alkaline earth metals;

[0009] The precursor glass powder is composed of the following components in terms of mole percentage: 26-48 mol% GeO2, 74-52 mol% P2O5;

[0010] The mass of the nitride red phosphor is 1-7% of the total mass of the precursor glass powder and the nitride red phosphor.

[0011] In the above technical solution, further, the fluorescent conversion glass is prepared by low-temperature rapid sintering of the raw materials through spark plasma sintering (SPS) technology.

[0012] Furthermore, the nitride red phosphor may generally be Sr2Si5N8:Eu2+, CaAlSiN3:Eu2+ or other nitride red phosphors.

[0013] The method for preparing the fluorescence conversion glass comprises the following steps:

[0014] After mixing and grinding GeO2 and P2O5, firstly performing a first annealing treatment, and then sintering, cooling, grinding and sieving to obtain the precursor glass powder;

[0015] The precursor glass powder is subjected to a second annealing treatment to eliminate internal stress, and then mixed with nitride red phosphor and sintered by SPS to obtain the fluorescent conversion glass.

[0016] In the above technical solution, further, the first annealing treatment has an annealing temperature of 510-560° C. and a time of 1 hour.

[0017] Furthermore, the sintering temperature is 1500-1600° C. and the sintering time is 0.5-1.5 h.

[0018] Furthermore, the sieving is to control the powder particle size to 100-150 μm.

[0019] Furthermore, the temperature of the second annealing treatment is 600-660° C., and the time is 2-4 hours.

[0020] Furthermore, the SPS sintering is carried out in graphite (usually with a diameter of 10 mm), at a pressure of 35-45 MPa, a heating rate of 60-90° C. / min, and the temperature is raised to 600-660° C. and then kept at this temperature for 3 minutes.

[0021] A white laser double-doped fluorescent glass material is prepared by adding green fluorescent powder to the raw materials of the fluorescent conversion glass, wherein the mass of the green fluorescent powder accounts for 10-30% of the total mass of the powder.

[0022] Application of the fluorescent conversion glass or fluorescent glass material as described in any one of the above items in laser lighting.

[0023] The fluorescent conversion glass of the present invention has excellent interface, high luminescence performance, excellent thermal stability, and high laser irradiation threshold, meeting the high performance requirements of laser lighting, and has a simple preparation process, is green and environmentally friendly, and has low production cost.

[0024] The key technical means adopted in the present invention include at least:

[0025] 1. Glass matrix selection: binary germanium phosphorus glass is used as the substrate, which has a high laser damage threshold and does not contain alkali metals and alkaline earth metals, reducing the interface reaction with the phosphor and improving the luminescence performance.

[0026] 2. Phosphor doping amount: Optimize the doping amount of nitride red phosphor (1% to 7%) to ensure the luminous performance while avoiding the performance degradation caused by excessive doping.

[0027] 3. Sintering technology: SPS sintering technology is used to achieve complete densification of glass materials at a lower temperature and in a shorter time, avoiding the problems of traditional melt quenching methods.

[0028] The key technical effects produced by the present invention are at least:

[0029] 1. Excellent interface: The interface between the glass matrix and the phosphor prepared by the present invention is clear.

[0030] 2. High-efficiency luminescence performance: The nitride red fluorescent glass prepared by the present invention has high luminescence intensity and meets the high-performance requirements of laser lighting.

[0031] 3. Excellent thermal stability: it can maintain stable luminescence performance at high temperatures.

[0032] 4. High laser irradiation threshold: can withstand the excitation of high power density laser and is not prone to luminescence quenching.

[0033] 5. Simple preparation process: SPS sintering technology is used to simplify the preparation process and reduce production costs.

[0034] 6. Green and environmentally friendly: No harmful substances are used in the preparation process, which meets environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0036] Figure 1 This is an electron microscope image of the particle size of the precursor glass powder prepared in Example 1 of the present invention;

[0037] Figure 2 XRD images of the nitride red fluorescent glass materials obtained in Examples 2 to 6 of the present invention;

[0038] Figure 3 The transmittance spectra of the nitride red fluorescent glass prepared in Examples 2 to 6 of the present invention in the 300 to 800 nm band (the illustrations from left to right are the actual images of the materials obtained in Examples 2 to 6 under sunlight irradiation);

[0039] Figure 4 This is a high-definition transmission electron microscope image of the nitride red fluorescent glass material obtained in Example 5 of the present invention;

[0040] Figure 5 The emission spectra of the nitride red fluorescent glass materials obtained in Examples 3 to 6 of the present invention in the wavelength range of 480 to 700 nm;

[0041] Figure 6 A line graph showing the relationship between the luminous flux, luminous efficiency and laser irradiation power density of the nitride red fluorescent glass material obtained in Examples 3 to 6 of the present invention under 450nm blue laser excitation;

[0042] Figure 7 The display index diagrams of different white diode devices prepared by doping dual-color phosphors (nitride red phosphor and green phosphor) with the binary germanium-phosphorus glass powder obtained in Example 1 of the present invention.

[0043] Figure 8 These are sample photos of plants under different lamps (the two lamps are the white laser diode (wLD) lamp designed by the present invention and a commercial light emitting diode (LED) lamp). DETAILED DESCRIPTION

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0046] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0047] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0048] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0049] Unless otherwise specified, the raw materials used in the embodiments of the present invention are all purchased from the market. The technical scheme of the present invention is further described below through examples. The raw materials of the high-efficiency fluorescent conversion glass of the present invention include the following components: nitride red phosphor and precursor glass powder; the precursor glass powder is a binary glass matrix powder containing only glass formers, which does not contain alkali metals and alkaline earth metals; in terms of molar percentage, the precursor glass powder is composed of the following components: 26-48 mol% GeO2, 74-52 mol% P2O5; the mass of the nitride red phosphor is 1-7% of the total mass of the precursor glass powder and the nitride red phosphor. The nitride red phosphor used in the following embodiments is Sr2Si5N8:Eu2+. In other embodiments of the present invention, CaAlSiN3:Eu2+ or other types of nitride red phosphors may also be used, which will not be repeated.

[0050] Example 1

[0051] Preparation of precursor glass powder:

[0052] After 30GeO2-70 P2O5 (mol%) is mixed and ground evenly, the ground mixture is placed in a pit furnace for annealing at a temperature of 550°C for 1 hour. Then, the annealed mixture is placed in a lifting furnace for melting at a temperature of 1550°C for 1 hour. After the melting is completed, the melt is cooled, ground and sieved (100-150μm) to obtain a precursor glass powder, i.e., binary germanium phosphorus glass powder.

[0053] The binary germanium-phosphorus glass powder prepared in Example 1 was observed by scanning electron microscopy. Figure 1 As shown, the average particle size of the glass particles is 100-150 μm.

[0054] Example 2

[0055] Preparation of binary germanium phosphorus glass:

[0056] The precursor glass powder obtained in Example 1 was annealed in an annealing furnace to eliminate internal stress. The annealing temperature was 650°C for 3 hours. Then, the annealed precursor glass powder (1 g) was placed in an SPS mold and sintered in graphite with a pressure of 45 MPa and a diameter of 10 mm. The heating rate was 80°C / min, and the temperature was raised to 660°C and kept for 3 minutes to obtain a transparent binary germanium-phosphorus glass.

[0057] Embodiment 3-6

[0058] Preparation of nitride red fluorescent glass:

[0059] The precursor glass powder obtained in Example 1 is annealed in an annealing furnace to eliminate internal stress. The annealing temperature is 650°C and the time is 3 hours. Then, the annealed precursor glass powder is mixed evenly with the nitride red phosphor at a mass ratio of 99:1, 97:3, 95:5 and 93:7 respectively (that is, the mass of the nitride red phosphor is 1%, 3%, 5% and 7% of the total powder mass). The mixture is placed in an SPS mold and sintered in graphite with a pressure of 45MPa and a diameter of 10mm. The heating rate is 80°C / min. After heating to 660°C and keeping warm for 3 minutes, fluorescent glasses with different nitride phosphor contents are obtained.

[0060] Example 7

[0061] Preparation of binary germanium phosphorus glass doped with two-color phosphor (nitride red phosphor Sr2Si5N8:Eu2+ and green phosphor Lu3Al5O12:Ce3+):

[0062] The glass powder obtained in Example 1 is uniformly mixed with 5% of nitride red phosphor and x% of green phosphor (x=10, 15, 20, 25, 30), and then sintered according to the same SPS sintering steps as in the present invention to obtain a dual-doped fluorescent glass material.

[0063] Example 8

[0064] The fluorescent glass prepared in Example 7 was prepared into a wLD device, and a commercial LED lamp was selected as a control group to evaluate the effects of different light qualities on the growth of tobacco plants.

[0065] Table 1

[0066]

[0067] The performance tests were performed on the materials prepared in Examples 1-7:

[0068] 1. Scanning electron microscope images

[0069] The sieved glass powder obtained in Example 1 was observed using a scanning electron microscope to obtain a scanning electron microscope image. It was observed that the average particle size of the glass particles was 100-150 μm.

[0070] 2. XRD pattern

[0071] Using Cu~K α The XRD images of the nitride red fluorescent glass materials obtained by X-ray diffraction test in radiation mode are as follows: Figure 2 As shown, it is proved that the nitride red phosphor is successfully embedded in the binary glass matrix and the nitride red phosphor crystals are not destroyed.

[0072] 3. Transmission spectrum

[0073] The binary germanium-phosphorus glass matrix material prepared in Example 2 and the nitride red fluorescent glass prepared in Examples 3-6 were measured in the 300-800 nm band using a spectrophotometer and an ultraviolet-visible-near infrared spectrometer to obtain transmission spectra, such as Figure 3 As shown. The results show that the binary germanium phosphorus glass prepared by the present invention has a high transmittance (84%), and the transmittance of the nitride red fluorescent glass gradually decreases with the increase of the phosphor content. The illustrations from left to right are the actual pictures of the samples prepared in Example 2 and Examples 3-6 under white light irradiation.

[0074] 4. High-resolution transmission electron microscopy

[0075] The nitride red fluorescent glass obtained in Example 5 was observed using a transmission electron microscope to obtain a high-definition transmission electron microscope image. Figure 4The image shows a clear interface between the nitride red phosphor and the binary glass matrix at the nanoscale, indicating a low degree of chemical and structural perturbation between the two. In addition, the lattice fringe spacing of the fluorescent glass is 0.2495nm, corresponding to the (002) crystal plane of the nitride red phosphor.

[0076] 5. Fluorescence spectrum

[0077] The fluorescence spectra of the nitride red fluorescent glass materials prepared in Examples 3-6 were tested under 450 nm laser diode pumping. Figure 5 As shown. Under the pumping of a laser diode with a wavelength of 450nm, broadband luminescence with a central wavelength of 628nm is obtained. In addition, as the content of nitride red phosphor increases, the emission intensity of the fluorescent glass continues to increase.

[0078] 6. Laser irradiation threshold test

[0079] The nitride red fluorescent glass material prepared in Example 3-6 was tested for luminous flux, luminous efficiency and laser irradiation density. The results are shown in Figure 6 Under the excitation of focused blue laser, the light flux first increases linearly with the increase of incident laser power density, and then drops sharply after reaching the peak, showing a typical luminescence saturation phenomenon. It is worth mentioning that the laser saturation threshold of the nitride red fluorescent glass in this study can reach 5.71W / mm 2 , which is a good level. This means that the proposed binary germanium phosphorus glass doped with nitride red phosphor can be used in high-power laser lighting. Before the luminescence saturation, the luminous efficiency continues to decline. When the concentration of nitride red phosphor is 5%, the luminous flux and luminous efficiency reach the maximum value, which are 104lm and 76lm / W respectively, both of which are relatively good levels at present.

[0080] 7. CRI of double-doped fluorescent glass (nitride red phosphor and green phosphor)

[0081] Binary germanium phosphorus glass was doped with nitride red phosphor and green phosphor (5% nitride red phosphor-x% green phosphor (x=10, 15, 20, 25, 30)). Fluorescent glass was prepared according to the preparation process of the present invention. The results are shown in FIG. Figure 7 .Depend on Figure 7 It can be seen that when the concentration of green phosphor is 25%, the color rendering index of the prepared fluorescent glass is as high as 89.5, which performs well in color reproduction quality.

[0082] 8. Comparison of plant growth under different lighting

[0083] The fluorescent glass (x=25) prepared in Example 7 was prepared into a wLD device, and a commercial LED lamp was selected as a control group to evaluate the effects of different light qualities on the growth of tobacco plants. The results are shown in Figure 8 .from Figure 8 It can be seen that under the same growth conditions (light intensity and temperature remain the same), tobacco plants treated with wLD light are significantly larger than those treated with LED light (that is, the smallest tobacco plant under wLD light is larger than the largest tobacco plant under LED light). In addition, careful observation of tobacco plants grown under these two types of light revealed that tobacco leaves under wLD light are more mature, brighter in color, and have a well-developed root system.

[0084] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A high-efficiency fluorescent conversion glass based on nitride red phosphor composite binary germanium phosphorus glass, characterized in that: Its raw materials include the following components: Nitride red phosphor and precursor glass powder; the precursor glass powder is a binary glass matrix powder containing only glass formers and does not contain alkali metals and alkaline earth metals; The precursor glass powder is composed of the following components in terms of mole percentage: 26-48 mol% GeO2, 74-52 mol% P2O5; The mass of the nitride red phosphor is 1-7% of the total mass of the precursor glass powder and the nitride red phosphor.

2. The high-efficiency fluorescent conversion glass based on nitride red phosphor composite binary germanium phosphorus glass according to claim 1, characterized in that: The fluorescent conversion glass is prepared by low-temperature rapid sintering of the raw materials through spark plasma sintering (SPS) technology.

3. The method for preparing high-efficiency fluorescent conversion glass based on nitride red phosphor composite binary germanium phosphorus glass according to claim 1, characterized in that: The following steps are involved: After mixing and grinding GeO2 and P2O5, firstly performing a first annealing treatment, and then sintering, cooling, grinding and sieving to obtain the precursor glass powder; The precursor glass powder is subjected to a second annealing treatment to eliminate internal stress, and then mixed with nitride red phosphor and sintered by SPS to obtain the high-efficiency fluorescent conversion glass.

4. The preparation method according to claim 3, characterized in that: The first annealing treatment has an annealing temperature of 510-560° C. and a time of 1 hour.

5. The preparation method according to claim 3, characterized in that: The sintering temperature is 1500-1600°C and the sintering time is 0.5-1.5h.

6. The preparation method according to claim 3, characterized in that: The sieving is to control the powder particle size to 100-150 μm.

7. The preparation method according to claim 3, characterized in that: The temperature of the second annealing treatment is 600-650° C. and the time is 2-4 hours.

8. The preparation method according to claim 3, characterized in that: The SPS sintering is carried out in graphite at a pressure of 35-45 MPa and a heating rate of 60-90° C. / min. The temperature is raised to 600-660° C. and then kept at that temperature for 3 minutes.

9. A white laser double-doped fluorescent glass material, characterized in that: Green fluorescent powder is added to the raw materials of the fluorescent conversion glass as claimed in claim 1, and the mass of the green fluorescent powder accounts for 10-30% of the total mass of the powder.

10. Use of the fluorescence conversion glass according to any one of claims 1 to 2, the fluorescence conversion glass obtained by the preparation method according to any one of claims 3 to 8, or the dual-doped fluorescence glass material according to claim 9 in laser lighting.

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