Composite fluorescent sheet and preparation method and application thereof

Abstract

The application provides a composite fluorescent sheet and a preparation method and application thereof. The composite fluorescent sheet comprises a diamond substrate, a modification layer and a fluorescent layer arranged in sequence. The material of the modification layer comprises refractory metal and carbide of the refractory metal, and the refractory metal is W and / or Mo. The fluorescent layer is an inorganic oxide fluorescent layer. The diamond with high thermal conductivity is used as the substrate, the modification layer is arranged between the diamond substrate and the fluorescent layer, the refractory metal W and / or Mo in the modification layer reacts with the diamond to generate refractory metal carbide, a chemical bond is formed between the diamond substrate and the modification layer, and the interface bonding strength is greatly improved. Compared with the inert surface of the diamond substrate, the refractory metal W and / or Mo on the surface of the modification layer can be stably combined with the inorganic oxide fluorescent layer.

Description

Technical Field

[0001] This invention belongs to the field of luminescent material preparation technology, specifically relating to a composite fluorescent sheet, its preparation method, and its application. Background Technology

[0002] In high-power laser-excited fluorescence conversion devices, the fluorescence layer cannot be used independently in high-power laser excitation scenarios due to its weak mechanical properties, lack of self-supporting structure, and insufficient heat dissipation and optical adaptability. It must rely on an optical substrate to support the fluorescence layer. Sapphire and quartz substrates have hydroxyl groups on their surfaces, which can form chemical bonds with inorganic oxide fluorescence layers, such as yttrium aluminum garnet precursors. Therefore, the fluorescence layer adheres strongly to sapphire and quartz substrates, and depositing the fluorescence layer onto these substrates can meet fluorescence requirements. However, due to the low thermal conductivity of sapphire and quartz substrates, the device damage threshold is low, leading to performance degradation and frequent replacements, making them unsuitable for high-power laser applications.

[0003] Diamond is a material with high thermal conductivity (50-60 times that of sapphire and 1000 times that of quartz). By depositing a fluorescent layer onto a diamond substrate using magnetron sputtering, the problem of low substrate thermal conductivity can be solved to meet the application requirements of high-power lasers. However, because the surface of diamond is inert (lacking hydroxyl groups), directly depositing an inorganic oxide fluorescent layer onto a diamond substrate results in poor interfacial adhesion between the diamond substrate and the inorganic oxide fluorescent layer, relying solely on van der Waals forces. Even slight thermal expansion and contraction can cause it to detach.

[0004] Therefore, there is an urgent need for a composite phosphor sheet that is suitable for high-power laser applications and has strong interfacial bonding. Summary of the Invention

[0005] The purpose of this invention is to provide a composite fluorescent sheet, its preparation method, and its application. The composite fluorescent sheet provided by this invention has high thermal conductivity and strong interfacial bonding.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: The present invention provides a composite phosphor sheet comprising a diamond substrate, a modified layer and a phosphor layer arranged sequentially; the modified layer is made of a refractory metal and a carbide of the refractory metal, wherein the refractory metal is W and / or Mo; the phosphor layer is an inorganic oxide phosphor layer.

[0007] Preferably, the thickness of the modified layer is 0.1~0.3μm.

[0008] Preferably, the refractory metal is W and Mo, and the mass ratio of W to Mo is (1~3):(2~4).

[0009] Preferably, the thickness of the diamond substrate is 1~3mm.

[0010] Preferably, the thickness of the fluorescent layer is 0.1~10μm.

[0011] Preferably, the fluorescent layer is made of cerium-doped yttrium aluminum garnet.

[0012] This invention also provides a method for preparing the composite fluorescent sheet described in the above technical solution, comprising the following steps: A refractory metal is magnetron sputtered onto the surface of a diamond substrate, followed by a first annealing treatment to form a modified layer on the surface of the diamond substrate. An inorganic oxide fluorescent layer is magnetron sputtered onto the surface of the modified layer, followed by a second annealing treatment to obtain a composite fluorescent sheet. The atmosphere for the first annealing treatment and the second annealing treatment is an inert atmosphere.

[0013] Preferably, the temperature of the first annealing is 500~1000℃ and the time is 30~60min.

[0014] Preferably, the second annealing temperature is 900~1500℃ and the time is 60~150min.

[0015] The present invention also provides the application of the composite fluorescent sheet described in the above technical solution or the composite fluorescent sheet prepared according to the preparation method described in the above technical solution in high-power lasers.

[0016] This invention provides a composite phosphor sheet comprising a diamond substrate, a modified layer, and a phosphor layer sequentially disposed therefrom. The modified layer is made of a refractory metal and a carbide of the refractory metal, wherein the refractory metal is W and / or Mo. The phosphor layer is an inorganic oxide phosphor layer. This invention utilizes diamond, which has high thermal conductivity, as the substrate. By placing a modified layer between the diamond substrate and the phosphor layer, the refractory metal W and / or Mo in the modified layer reacts with the diamond to form refractory metal carbides, forming chemical bonds between the diamond substrate and the refractory metal, significantly improving the interfacial bonding strength. Compared to the inert surface of the diamond substrate, the refractory metal W and / or Mo in the modified layer can stably bond with the inorganic oxide phosphor layer. Experimental results show that the composite phosphor sheet prepared by this invention has high thermal conductivity. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the composite fluorescent sheet of the present invention (1-diamond substrate layer, 2-modified layer, 3-fluorescent layer); Figure 2 The excitation and emission spectra of the composite fluorescent sheet prepared in Example 1 of this invention are shown. Detailed Implementation

[0018] The present invention provides a composite phosphor sheet comprising a diamond substrate, a modified layer and a phosphor layer arranged sequentially; the modified layer is made of a refractory metal and a carbide of the refractory metal, wherein the refractory metal is W and / or Mo; the phosphor layer is an inorganic oxide phosphor layer.

[0019] The composite fluorescent sheet provided by this invention includes a diamond substrate.

[0020] In this invention, the thickness of the diamond substrate is preferably 1-3 mm; in one embodiment, the thickness of the diamond substrate can be 1 mm, 2 mm, or 3 mm. In another embodiment, the shape of the diamond substrate can be circular or square / rectangular; when the shape is circular, the thickness-to-diameter ratio of the diamond substrate can be (1-3):(6-10). In an embodiment of this invention, the diamond substrate is circular, 1 mm thick, and 10 mm in diameter, with a thickness-to-diameter ratio of 1:10. By controlling the thickness, shape, and thickness-to-diameter ratio of the diamond substrate within the above ranges, this invention facilitates sufficient lateral heat expansion, rapid and uniform heat distribution, and ensures good thermal conductivity.

[0021] The composite fluorescent sheet provided by the present invention further includes a modified layer disposed on the diamond substrate.

[0022] In this invention, the thickness of the modified layer is preferably 0.1~0.3 μm; as one embodiment of this invention, the thickness of the modified layer can be 0.1 μm, 0.2 μm, or 0.3 μm. By controlling the thickness of the modified layer within the above range, this invention can ensure the bonding strength between the diamond substrate and the modified layer while minimizing the increase in additional thermal resistance.

[0023] In this invention, the modified layer material comprises a refractory metal and a carbide of the refractory metal. The refractory metal is W and / or Mo, preferably W and Mo; as one embodiment of this invention, the refractory metal can be W, Mo, or W and Mo; when the refractory metal is W and Mo, the mass ratio of W to Mo can be (1~3):(2~4) or (1~1.5):(2~4); in an embodiment of this invention, the refractory metal is W and Mo, and the mass ratio of W to Mo is 2:2. The carbide of the refractory metal is preferably WC. x and / or MoC x (x=0.5~1); As one embodiment of the present invention, the carbide of the refractory metal can be WC. x (x=0.5~1), can also be MoC x (x=0.5~1), can also be used for WC xand MoC x (x=0.5~1); the carbide of the refractory metal is WC. x and MoC x When x = 0.5~1, the WC x and MoC x The mass ratio can be (1~3):(2~4).

[0024] In this invention, the refractory metal carbide is preferably prepared by in-situ reaction of the refractory metal in the modified layer with the diamond substrate; the refractory metal carbide is preferably distributed at the contact surface between the modified layer and the diamond substrate. In this invention, when the refractory metal is W, the refractory metal carbide can be WC. x (x=0.5~1); when the refractory metal is Mo, the carbide of the refractory metal can be MoC. x (x=0.5~1); when the refractory metal is W and Mo, the carbide of the refractory metal is WC. x and MoC x (x=0.5~1). This invention utilizes the reaction of refractory metals W and / or Mo in the modified layer with diamond to generate refractory metal carbides. The refractory metal carbides are distributed on the contact surface between the modified layer and the diamond substrate, forming chemical bonds between the diamond substrate and the modified layer, which greatly improves the interfacial bonding strength.

[0025] The composite fluorescent sheet provided by the present invention further includes a fluorescent layer disposed on the modified layer.

[0026] In this invention, the thickness of the fluorescent layer is preferably 0.1~10μm; as one embodiment of this invention, the thickness of the fluorescent layer can be 2μm, 5μm, or 7μm.

[0027] The fluorescent layer is an inorganic oxide fluorescent layer; as one embodiment of the present invention, the material of the fluorescent layer can be cerium-doped yttrium aluminum garnet, and the doping amount of cerium can be 0.05 wt%. The main advantages of cerium-doped yttrium aluminum garnet as a fluorescent layer are high luminous efficiency, good thermal stability, long lifetime, good spectral adaptability, and mature technology.

[0028] A schematic diagram of the composite fluorescent sheet provided by this invention is shown below. Figure 1 (1 represents the diamond base layer, 2 represents the modified layer, and 3 represents the fluorescent layer) As shown, from bottom to top, they are the diamond base layer, the modified layer, and the fluorescent layer.

[0029] The composite phosphor sheet provided by this invention uses diamond, which has high thermal conductivity, as a substrate. A modification layer is set between the diamond substrate and the phosphor layer. The refractory metals W and / or Mo in the modification layer react with the diamond to generate refractory metal carbides. The refractory metal carbides form chemical bonds between the diamond substrate and the modification layer, which can significantly improve the interfacial bonding strength. Compared with the inert surface of the diamond substrate, the refractory metals W and / or Mo on the surface of the modification layer can be stably bonded to the inorganic oxide phosphor layer.

[0030] This invention also provides a method for preparing the composite fluorescent sheet described in the above technical solution, comprising the following steps: A modified layer is obtained by magnetron sputtering a refractory metal onto a diamond substrate and then performing a first annealing treatment. An inorganic oxide fluorescent layer is magnetron sputtered onto the surface of the modified layer, followed by a second annealing treatment to obtain a composite fluorescent sheet. The atmosphere for the first annealing treatment and the second annealing treatment is an inert atmosphere.

[0031] The present invention involves magnetron sputtering a refractory metal onto a diamond substrate surface, followed by a first annealing treatment to obtain a modified layer.

[0032] In this invention, the diamond substrate is preferably polished before use. Polishing reduces the surface roughness of the substrate and improves the uniformity and density of the metal film.

[0033] In one embodiment of the present invention, the target material for magnetron sputtering can be a pure metal or an alloy; the purity of the target material can be >99.99%. In this invention, the atmosphere for magnetron sputtering is preferably argon; in one embodiment of the present invention, the base vacuum level for magnetron sputtering can be 1×10⁻⁶. -6 ~1×10 -5 Pa; the working gas pressure of the magnetron sputtering can be 0.1~1 Pa.

[0034] In this invention, the atmosphere for the first annealing is an inert atmosphere, preferably argon; as one embodiment of this invention, the inert atmosphere flow rate can be 10~200 sccm. In this invention, the temperature for the first annealing is preferably 500~1000℃, and the annealing time is preferably 30~60 min; as one embodiment of this invention, the temperature for the first annealing can be 500℃, 750℃, or 850℃; the annealing time can be 30 min, 40 min, or 50 min. These annealing conditions can prevent graphitization of the diamond substrate and allow the refractory metal sputtered by magnetron sputtering to form refractory metal carbides at the interface between the modified layer and the diamond substrate, significantly improving the interfacial bonding strength between the modified layer and the diamond substrate.

[0035] In one embodiment of the present invention, the first annealing can be carried out in a tube furnace, wherein the number of particles larger than 10 μm in the furnace wall can be controlled to below 200 counts. These conditions maintain a high level of cleanliness in the furnace wall, preventing the entry of impurities during the annealing process.

[0036] After obtaining the modified layer, the present invention magnetron sputters an inorganic oxide fluorescent layer on the surface of the modified layer, and then performs a second annealing treatment to obtain a composite fluorescent sheet.

[0037] In this invention, the target material for magnetron sputtering is preferably selected based on the material of the inorganic oxide fluorescent layer. In this invention, the atmosphere for magnetron sputtering is preferably argon; as one embodiment of this invention, the base vacuum level for magnetron sputtering can be 1×10⁻⁶. -6 ~1×10 -5 Pa, the working gas pressure of the magnetron sputtering can be 1~3Pa; the magnetron sputtering can use an RF power supply, the power of which can be 100~500W.

[0038] In this invention, the atmosphere for the second annealing is an inert atmosphere, preferably argon; as one embodiment of this invention, the inert atmosphere flow rate can be 10~200 sccm. In this invention, the temperature for the second annealing is preferably 900~1500℃, and the annealing time is preferably 60~150 min; as one embodiment of this invention, the temperature for the second annealing can be 1000℃, 1100℃, or 1300℃; the annealing time can be 80 min, 100 min, or 120 min. Annealing under the above conditions can improve the fluorescence properties of the fluorescent layer; further improve the interfacial bonding strength between the modified layer and the diamond substrate, and stably bond the refractory metal on the surface of the modified layer with the inorganic oxide fluorescent layer (in the inert atmosphere at the above high temperature, metal-ceramic interfacial interdiffusion occurs, the refractory metal W / Mo diffuses slightly to the surface of the inorganic oxide fluorescent layer, and the O of the inorganic oxide fluorescent layer segregates to the metal surface, spontaneously forming a continuous interfacial transition region with thermodynamically stable structure).

[0039] In one embodiment of the present invention, the second annealing can be performed in a tube furnace, wherein the number of particles larger than 10 μm in the furnace wall can be controlled to below 200 counts. These conditions maintain a high level of cleanliness in the furnace wall, preventing the entry of impurities during the annealing process.

[0040] The method for preparing composite fluorescent sheets provided by this invention can ensure strong interfacial bonding of the composite fluorescent sheets.

[0041] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0042] Example 1 The composite phosphor sheet consists of a diamond substrate, a modified layer, and a phosphor layer arranged sequentially. The diamond substrate is circular with a thickness of 1 mm and a diameter of 10 mm. The modified layer has a thickness of 0.2 μm and is made of a refractory metal (W and Mo in a mass ratio of 1:1) and a refractory metal carbide (WC). x and MoC x Composed of (x=0.5~1, mass ratio 1:1); the thickness of the fluorescent layer is 2μm, and the fluorescent layer is cerium-doped yttrium aluminum garnet (cerium doping amount is 0.05wt%). Preparation method of composite fluorescent sheet: The surface of a diamond substrate is polished, and then refractory metals W and Mo are magnetron sputtered onto the diamond substrate surface. The target material for magnetron sputtering is a W / Mo alloy with a mass ratio of 1:1 (purity >99.99%). The atmosphere for magnetron sputtering is argon, and the base vacuum degree of the magnetron sputtering is 8 × 10⁻⁶. -6 Pa, working pressure is 0.1 Pa; then the first annealing treatment is carried out in an argon atmosphere, the argon atmosphere flow rate is 100 sccm, the first annealing temperature is 500℃, and the time is 30 min, to obtain the modified layer; An inorganic oxide fluorescent layer (cerium-doped yttrium aluminum garnet, cerium doping amount of 0.05 wt%) was magnetron sputtered onto the surface of the modified layer. The magnetron sputtering atmosphere was argon, and the base vacuum degree of the magnetron sputtering was 1 × 10⁻⁶. -5 The working pressure is 2Pa, and an RF power supply with a power of 200W is used. Then, a second annealing treatment is performed in an argon atmosphere with an argon gas flow rate of 100sccm, an annealing temperature of 1300℃, and a holding time of 100min to obtain a composite fluorescent sheet.

[0043] The fluorescence properties of the composite fluorescent sheet prepared in Example 1 were detected using a fluorescence microscope and spectrophotometer. A 460 nm laser light was used, and emission light was used at 340 nm and 456 nm, respectively. The excitation and emission spectra of the obtained composite fluorescent sheet are shown below. Figure 2 As shown.

[0044] from Figure 2 As can be seen, the composite fluorescent sheet provided by the present invention can achieve the effect of emitting fluorescence at a specific wavelength.

[0045] The thermal conductivity of the composite fluorescent sheet prepared in Example 1 was tested using an LFA 467. The testing principle was as follows: a short-pulse laser irradiated one side of the sample, and an infrared detector measured the temperature rise curve of the other side. The thermal diffusivity α was calculated, and then combined with the specific heat C... p Density ρ, thermal conductivity λ = α × C is calculated using the formula. p The measured thermal conductivity is 2100 W / (m·K).

[0046] As can be seen from the above embodiments, the composite fluorescent sheet provided by the present invention is suitable for high-power laser applications and has high thermal conductivity.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite phosphor sheet, comprising a diamond substrate, a modified layer, and a phosphor layer sequentially disposed therefrom; the modified layer is made of a refractory metal and a carbide of the refractory metal, wherein the refractory metal is W and / or Mo; and the phosphor layer is an inorganic oxide phosphor layer.

2. The composite fluorescent sheet according to claim 1, characterized in that, The thickness of the modified layer is 0.1~0.3μm.

3. The composite fluorescent sheet according to claim 1, characterized in that, The refractory metals are W and Mo, and the mass ratio of W to Mo is (1~3):(2~4).

4. The composite fluorescent sheet according to claim 1, characterized in that, The thickness of the diamond substrate is 1~3mm.

5. The composite fluorescent sheet according to claim 1, characterized in that, The thickness of the fluorescent layer is 0.1~10μm.

6. The composite fluorescent sheet according to claim 1 or 5, characterized in that, The fluorescent layer is made of cerium-doped yttrium aluminum garnet.

7. A method for preparing the composite fluorescent sheet according to any one of claims 1 to 6, comprising the following steps: A refractory metal is magnetron sputtered onto the surface of a diamond substrate, followed by a first annealing treatment to form a modified layer on the surface of the diamond substrate. An inorganic oxide fluorescent layer is magnetron sputtered onto the surface of the modified layer, followed by a second annealing treatment to obtain a composite fluorescent sheet. The atmosphere for the first annealing treatment and the second annealing treatment is an inert atmosphere.

8. The method for preparing the composite fluorescent sheet according to claim 7, characterized in that, The temperature of the first annealing is 500~1000℃, and the time is 30~60min.

9. The method for preparing the composite fluorescent sheet according to claim 7, characterized in that, The second annealing temperature is 900~1500℃, and the time is 60~150min.

10. The application of the composite phosphor sheet according to any one of claims 1 to 6 or the composite phosphor sheet prepared according to the preparation method according to any one of claims 7 to 9 in high-power lasers.

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