Short-wave infrared fluorescent ceramic and preparation method and application thereof

Abstract

The application provides a short-wave infrared fluorescent ceramic and a preparation method and application thereof. The short-wave infrared fluorescent ceramic has a chemical composition of Y 2‑z (Ca 1‑x M x )Al 4‑y SiO 12 :yCr 3+ ,zEr 3+ ; wherein M is one or more of Mg, Sr and Ba elements. The preparation method comprises the following steps: S1, taking oxides, nitrates, halides or carbonates containing Y, Ca, M, Al, Si, Cr and Er elements as raw materials according to the chemical composition and the metering ratio, wherein M is one or more of Mg, Sr and Ba, and then mixing the raw materials to obtain a uniform mixture; S2, subjecting the uniform mixture to a melting treatment, and then cooling to obtain a transparent glass sample; and S3, placing the transparent glass sample into a tube furnace with an atmosphere, and subjecting the transparent glass sample to a heat treatment at 900-1300 DEG C under normal pressure, and then sequentially cooling and polishing to obtain the short-wave infrared fluorescent ceramic. The short-wave infrared fluorescent ceramic prepared by the application has high transmittance, a wide emission spectrum coverage range, high luminescent quantum efficiency and excellent thermal stability.

Description

Technical Field

[0001] This invention relates to the field of fluorescent ceramic preparation technology, and more specifically, to a short-wave infrared fluorescent ceramic, its preparation method, and its application. Background Technology

[0002] Fluorescence imaging, with its advantages of high detection sensitivity, cost-effectiveness, and lack of radiation hazards, has become one of the important technologies in biomedical applications. Among them, visible-near-infrared fluorescence imaging is easily affected by factors such as limited light penetration and tissue autofluorescence interference. In contrast, short-wave infrared (1000-1700nm) fluorescence imaging, which has been developed in recent years, is regarded as the most promising next-generation fluorescence imaging technology due to its deeper penetration depth, higher imaging resolution and sensitivity, lower background noise, and higher signal-to-noise ratio.

[0003] Short-wave infrared light sources are an indispensable component of this technology. Compared to incandescent lamps, halogen lamps, short-wave infrared LEDs, and short-wave infrared lasers, fluorescent conversion LEDs have advantages such as low price, high spectral tunability, and miniaturization. However, current short-wave infrared luminescent materials face problems such as low quantum efficiency, poor fluorescence thermal stability, and physicochemical stability. For example, non-patent literature (Jin, S., Li, R., Huang, H. et al. Compact ultrabroadband light-emitting diodes based on lanthanide-doped lead-free double perovskites. LightSci Appl 11, 52 (2022).) discloses a fluorescent glass with the composition Bi / Er:Cs2AgInCl6, which emits near-infrared light with a quantum efficiency of only 45.6% under 350nm light excitation; another example is non-patent literature (Zhang, G., Dang, P., Lian, H., Xiao, H., Cheng, Z., Lin, J. (2022). Er 3+ / Yb 3+A fluorescent material with the composition Cs2NaErCl6 that emits NIR-II near-infrared light under 379 nm ultraviolet light excitation was disclosed in Laser & Photonics Reviews, 16(8), 2200078., with an internal quantum efficiency of only 4%. Furthermore, short-wave infrared phosphors (such as Chinese invention patent CN115558491B, a broadband short-wave infrared phosphor and its preparation method and light-emitting device) require encapsulation with organic resin or silicone. Since the blue light to short-wave infrared spectral conversion process inevitably generates a large amount of heat, and organic materials have poor physicochemical stability and low thermal conductivity, such organic-inorganic composite phosphor converters cannot be applied to high-power light-emitting devices. Moreover, the existing technology for preparing short-wave infrared fluorescent ceramics involves cumbersome steps, low efficiency, and requires high pressure and high vacuum conditions.

[0004] Therefore, developing all-inorganic short-wave infrared fluorescent converters with high quantum efficiency and good thermal stability is of great significance for obtaining high-power short-wave infrared light sources. Summary of the Invention

[0005] One of the technical problems to be solved by the present invention is to provide a short-wave infrared fluorescent ceramic to solve the problems of low quantum efficiency, poor thermal stability and poor physicochemical stability of the existing short-wave infrared fluorescent ceramics.

[0006] To address the aforementioned technical problems, this invention provides a short-wave infrared fluorescent ceramic, wherein the chemical composition of the short-wave infrared fluorescent ceramic is Y. 2-z (Ca 1-x M x Al 4-y SiO 12 :yCr 3+ ,zEr 3+ Wherein, M is one or more of Mg, Sr, and Ba elements, and the parameters x, y, and z satisfy the following conditions:

[0007] 0.0≤x≤1.0, 0.01≤y≤0.2, 0.05≤z≤0.5.

[0008] In one possible implementation, the short-wave infrared fluorescent ceramic can emit short-wave near-infrared light with a wavelength range of 1400–1700 nm when excited by blue light.

[0009] In one possible implementation, 0.0≤x≤0.5, 0.01≤y≤0.1, 0.05≤z≤0.5.

[0010] In one possible implementation, 0.3≤x≤0.5, 0.05≤y≤0.1, and 0.05≤z≤0.4.

[0011] In one possible implementation, 0.3≤x≤0.4, 0.08≤y≤0.1, and 0.1≤z≤0.3.

[0012] Compared with existing technologies, this invention provides a near-infrared fluorescent ceramic with high transmittance, wide emission spectrum coverage, high quantum efficiency, and excellent thermal stability.

[0013] The second technical problem to be solved by the present invention is to provide a method for preparing short-wave infrared fluorescent ceramics, so as to solve the problems that the existing technology has relatively complicated steps, low efficiency and high pressure and high vacuum conditions in the preparation of short-wave infrared fluorescent ceramics.

[0014] To address the above problems, this invention provides a method for preparing the aforementioned short-wave infrared fluorescent ceramic, comprising the following steps:

[0015] S1: According to the chemical composition and stoichiometric ratio, weigh out a compound containing elements Y, Ca, M, Al, Si, Cr and Er as a raw material, wherein the compound is one or more of oxides, nitrates, halides and carbonates, wherein the M element is one or more of Mg, Sr and Ba, and then mix the raw materials to obtain a homogeneous mixture.

[0016] S2: The homogeneous mixture obtained in step S1 is melted at 1500-2000°C and then cooled to obtain a transparent glass sample;

[0017] S3: The transparent glass sample obtained in step S2 is placed in a tube furnace with an atmosphere and heat-treated at 900-1300°C under normal pressure. After cooling and polishing, short-wave infrared fluorescent ceramic is obtained.

[0018] Compared with the prior art, the present invention provides a method for preparing the short-wave infrared fluorescent ceramic. The preparation process of the present invention is simple and efficient, and does not require extreme conditions such as high pressure and high vacuum. Near-infrared fluorescent ceramics can be prepared under normal pressure by glass crystallization.

[0019] This invention involves preparing raw materials into a glass form, allowing elements to be mixed at the atomic scale at high temperatures. The highly homogenized glass is then crystallized to obtain a transparent fluorescent ceramic with fewer surface defects in the grains. Due to the reduction in luminescence quenching centers, Cr... 3+ –Er 3+ Efficient energy transfer between them can effectively improve the luminescence performance of short-wave near-infrared fluorescent ceramics.

[0020] In one possible implementation, the heat treatment time in step S3 is 2 to 12 hours.

[0021] In one possible implementation, the heat treatment time in step S3 is 4 to 10 hours.

[0022] In one possible implementation, in step S3, the atmosphere is at least one of a mixture of nitrogen and hydrogen, a mixture of argon and hydrogen, and carbon monoxide.

[0023] The third technical problem to be solved by the present invention is to provide an application of short-wave infrared fluorescent ceramics, wherein the application is to use short-wave infrared fluorescent ceramics in short-wave infrared light-emitting devices, so as to solve the problem that in the application of existing short-wave infrared fluorescent ceramics (including light-emitting devices), organic resin or silicone is required to encapsulate the fluorescent ceramic powder. Through the short-wave infrared fluorescent ceramics of the present invention, the defect that the same component powder materials cannot be applied to high-power light-emitting devices can be better solved.

[0024] To address the aforementioned problems, the present invention provides an application of short-wave infrared fluorescent ceramics, the application of which includes using the short-wave infrared fluorescent ceramics in a short-wave infrared emitting device.

[0025] In one possible implementation, the short-wave infrared light-emitting device includes an excitation source and a light-emitting layer. The excitation source is a blue LED chip, a laser diode, or an organic EL light-emitting device, and the light-emitting layer includes the short-wave infrared fluorescent ceramic. The light-emitting device is fabricated by directly covering the excitation source with the near-infrared fluorescent ceramic.

[0026] Compared to existing technologies, the short-wave infrared fluorescent ceramic of the present invention, when applied to short-wave infrared light-emitting devices, can be directly combined with high-power LEDs / LDs and other solid-state excitation light sources to encapsulate high-power near-infrared light-emitting devices without the use of curing adhesive. The light-emitting device prepared by the above-mentioned application of the present invention effectively solves the problem of the decline in light-emitting performance caused by the aging of organic curing adhesive in traditional powder encapsulation devices during long-term high-temperature operation of LED chips. Attached Figure Description

[0027] Figure 1The XRD patterns are of the samples prepared in Comparative Example 1 and Examples 1, 5, and 6.

[0028] Figure 2 The excitation and emission spectra of the samples prepared in Comparative Example 1 and Example 1 are shown.

[0029] Figure 3 The thermal stability test was performed on the samples prepared in Comparative Example 1 and Examples 1 and 3.

[0030] Figure 4 This is the spectrum of the LED device formed by combining the sample prepared in Example 1 with a 450nm blue LED package. Detailed Implementation

[0031] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0033] This invention provides a short-wave infrared fluorescent ceramic, wherein the chemical composition of the short-wave infrared fluorescent ceramic is Y. 2-z (Ca 1-x M x Al 4-y SiO 12 :yCr 3+ ,zEr 3+ Wherein, M is one or more of Mg, Sr, and Ba elements, and the parameters x, y, and z satisfy the following conditions:

[0034] 0.0≤x≤1.0, 0.01≤y≤0.2, 0.05≤z≤0.5.

[0035] As a preferred solution, 0.0≤x≤0.5, 0.01≤y≤0.1, 0.05≤z≤0.5.

[0036] As a preferred solution, 0.3≤x≤0.5, 0.05≤y≤0.1, 0.05≤z≤0.4.

[0037] As a preferred solution, 0.3≤x≤0.4, 0.08≤y≤0.1, 0.1≤z≤0.3.

[0038] As a preferred embodiment, the short-wave infrared fluorescent ceramic can emit short-wave near-infrared light with a wavelength range of 1400–1700 nm when excited by blue light.

[0039] The present invention also provides a method for preparing the short-wave infrared fluorescent ceramic, comprising the following steps:

[0040] S1: According to the chemical composition and stoichiometric ratio described in claim 1, a compound containing elements Y, Ca, M, Al, Si, Cr, and Er is weighed as a raw material, wherein the compound is one or more of oxides, nitrates, halides, and carbonates, wherein the M element is one or more of Mg, Sr, and Ba, and then the raw materials are mixed to obtain a homogeneous mixture.

[0041] S2: The homogeneous mixture obtained in step S1 is melted at 1500-2000°C and then cooled to obtain a transparent glass sample;

[0042] S3: The transparent glass sample obtained in step S2 is placed in a tube furnace with an atmosphere and heat-treated at 900-1300°C under normal pressure. After cooling and polishing, short-wave infrared fluorescent ceramic is obtained.

[0043] As a preferred embodiment, in step S3, the heat treatment time is 2 to 12 hours.

[0044] As a preferred embodiment, in step S3, the heat treatment time is 4 to 10 hours.

[0045] As a preferred embodiment, in step S3, the atmosphere is at least one of a mixture of nitrogen and hydrogen, a mixture of argon and hydrogen, and carbon monoxide.

[0046] The present invention also provides an application of short-wave infrared fluorescent ceramics, the application of which includes using short-wave infrared fluorescent ceramics in short-wave infrared light-emitting devices.

[0047] As a preferred embodiment, the short-wave infrared light-emitting device includes an excitation source and a light-emitting layer. The excitation source is a blue LED chip, a laser diode, or an organic EL light-emitting device, and the light-emitting layer includes the short-wave infrared fluorescent ceramic. The light-emitting device is prepared by directly covering the excitation source with the near-infrared fluorescent ceramic.

[0048] The following section further elaborates on the above-mentioned technical solution of the present invention based on actual experimental data and conditions:

[0049] Example 1:

[0050] S1: According to the following molecular formula Y 1.9 CaAl 3.99 SiO12 0.01Cr 3+ 0.1Er 3+ Yttrium oxide, aluminum oxide, calcium carbonate, silicon dioxide, chromium oxide, and erbium oxide were weighed out as raw materials according to the specified ratio. They were placed in an agate mortar, and about 3 ml of alcohol was added. The mixture was then stirred and ground for about 30 minutes until homogeneous. The resulting powder mixture was then placed in a mold, and the pressure of the tablet press was set to 20 MPa and maintained for 3 minutes. Finally, the pressed tablets were removed, crushed, and weighed to approximately 200 mg.

[0051] S2: In an air suspension furnace equipped with a dual-beam carbon dioxide laser, high-purity oxygen is used as the carrier gas to suspend and melt the sample, keeping it in a molten state for about 30 seconds. The melt is then rapidly cooled by cutting off the laser to obtain glass spheres with the corresponding composition.

[0052] S3: Next, the obtained glass spheres were placed in a high-temperature box furnace and heated to 1000℃ at a rate of 10℃ / min under a nitrogen-hydrogen mixed atmosphere, and held at that temperature for 2 hours. After natural cooling, highly crystalline broadband near-infrared fluorescent ceramics were obtained. These were then ground into sheets and polished to obtain broadband near-infrared fluorescent ceramics with an emission peak of approximately 760nm under 400–700nm excitation. This fluorescent ceramic exhibited an internal quantum efficiency of 85%, thermal stability of 85%, and transmittance of 45%.

[0053] like Figure 1 The figure shows the XRD pattern of the sample prepared in Example 1. As can be seen from the figure, the prepared NIR-II region near-infrared fluorescent ceramic belongs to the cubic crystal phase with a garnet structure.

[0054] like Figure 2 As shown, the near-infrared fluorescent ceramic prepared in Example 1 emits near-infrared light with a peak value of 1520 nm in the NIR-II region when excited by a light source in the range of 400-700 nm, with an internal quantum efficiency of 85%.

[0055] like Figure 3 The figure shows the thermal stability test of the sample prepared in Example 1. As can be seen from the figure, the prepared sample has good thermal stability, and its integrated intensity at 150°C is 85% of the initial temperature.

[0056] like Figure 4 As shown, the sample prepared in Example 1, combined with the spectrum of the LED device packaged with a 450nm blue LED, covers the entire NIR-II region and can be applied to related fields such as fluorescence imaging technology.

[0057] Comparative Example 1

[0058] Comparative Example 1 is similar to Example 1, except that the composition of the raw materials is different. Comparative Example 1 specifically includes:

[0059] S1: According to the following molecular formula Y2CaAl 3.99 SiO 12 0.01Cr 3+ Yttrium oxide, aluminum oxide, calcium carbonate, silicon dioxide, and chromium oxide were weighed out as raw materials according to the specified ratio. They were placed in an agate mortar, and about 3 ml of alcohol was added. The mixture was then stirred and ground for about 30 minutes until homogeneous. The resulting powder mixture was then placed in a mold, and the pressure of the tablet press was set to 20 MPa and maintained for 3 minutes. Finally, the pressed tablets were removed, crushed, and weighed to approximately 200 mg.

[0060] S2: In an air suspension furnace equipped with a dual-beam carbon dioxide laser, high-purity oxygen is used as the carrier gas to suspend and melt the sample, keeping it in a molten state for about 30 seconds. The melt is then rapidly cooled by cutting off the laser to obtain glass spheres with the corresponding composition.

[0061] S3: Next, the obtained glass spheres were placed in a high-temperature box furnace and heated to 1000°C at a rate of 10°C / min under a nitrogen-hydrogen mixed atmosphere, and held at that temperature for 2 hours. After natural cooling, highly crystalline broadband near-infrared fluorescent ceramics were obtained. These were then ground into sheets and polished to obtain broadband near-infrared fluorescent ceramics with an emission peak of approximately 760nm under 400–700nm excitation. Compared to Example 1, Comparative Example 1, which was not doped with Er, could not achieve luminescence at 1400–1700nm. This fluorescent ceramic had an internal quantum efficiency of 80%, a thermal stability of 70%, and a transmittance of 40%.

[0062] Example 2

[0063] Example 2 is similar to Example 1, except that the heat treatment temperature was changed to 1100℃ and held for 4 hours. All other preparation steps and process conditions were the same as in Example 1. The excitation and emission spectra, thermal stability, and internal quantum efficiency of this example are similar to those of Example 1, with an internal quantum efficiency of 96% and a total transmittance of 25% at 800 nm when the sample thickness is 0.5 mm.

[0064] Example 3

[0065] Example 3 is similar to Example 1, except that the component in Example 1 is changed to Y. 1.8 CaAl 3.98 SiO 12 0.02Cr 3+ 0.2Er 3+ The other preparation steps and process conditions are the same as in Example 1. The excitation and emission spectra, internal quantum efficiency, and total transmittance of this example are similar to those of Example 1. Figure 3 As shown, the thermal stability of the sample prepared in Example 3 is as high as 92%.

[0066] Example 4

[0067] Example 4 is similar to Example 1, except that the component in Example 1 is changed to Y. 1.6 CaAl 3.9 SiO 12 0.1Cr 3+ 0.4Er 3+ Other preparation steps and process conditions are the same as in Example 2. The excitation and emission spectra, thermal stability, and total transmittance of this example are similar to those of Example 1. The internal quantum efficiency of the sample prepared in Example 4 is 87%.

[0068] Examples 5 to 10:

[0069] Examples 5-10 are similar to Example 1. The corresponding raw materials were weighed according to the chemical formulas and stoichiometric ratios in Table 1. The heat treatment temperature and atmosphere are shown in Table 1. All other steps are the same as in the examples above. Table 1 shows the total transmittance of a 0.5 mm thick sample at a wavelength of 800 nm.

[0070] Table 1 Chemical composition, reaction conditions, and product performance of Examples 1-10

[0071]

[0072]

[0073] The comparison between the descriptions of Examples 1-10 and Comparative Example 1 further demonstrates that the fluorescent ceramic prepared by the method of the present invention for preparing short-wave infrared fluorescent ceramics possesses high internal quantum efficiency, thermal stability, and transmittance. As shown in Table 1, in the above embodiments of the present invention, by controlling different element selections and ratios, different heat treatment temperatures and durations, and other process conditions, the spectral range, light transmittance, and quantum efficiency of the product can be adjusted. After further selecting a preferred range of raw materials, both transmittance and quantum efficiency can reach high levels. Obviously, the above embodiments are merely examples for clear illustration. Other variations or modifications can be made based on the above description, and any obvious variations or modifications derived therefrom are still within the scope of protection of the present invention. The glass preparation in the above embodiments of the present invention uses an air suspension furnace method; however, the preparation method is not limited to this. Other methods that can fully melt and rapidly cool the raw materials can also obtain the glass described in the present invention. Furthermore, various different embodiments of the present invention can be arbitrarily combined, as long as they do not violate the spirit of the present invention, they should also be considered as the content disclosed in the present invention.

[0074] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0075] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing short-wave infrared fluorescent ceramics, characterized in that, Includes the following steps: S1: According to the chemical composition and stoichiometric ratio, weigh out a compound containing elements Y, Ca, M, Al, Si, Cr and Er as a raw material, wherein the compound is one or more of oxides, nitrates, halides and carbonates, and the M element is one or more of Mg, Sr and Ba. Then mix the raw materials to obtain a homogeneous mixture. S2: The homogeneous mixture obtained in step S1 is melted at 1500~2000℃ and then cooled to obtain a transparent glass sample; S3: The transparent glass sample obtained in step S2 is placed in a tube furnace with an atmosphere and heat-treated at 900~1300℃ under normal pressure. After cooling and polishing, short-wave infrared fluorescent ceramics are obtained. The chemical composition of the short-wave infrared fluorescent ceramic is Y. 2-z (Ca 1-x M x Al 4-y SiO 12 : y Cr 3+ , z Er 3+ The short-wave infrared fluorescent ceramic, when excited by blue light, can emit wavelengths in the range of 1400–1700 nm; wherein M is one or more of Mg, Sr, and Ba, and the parameters... x y z The following conditions must be met: 0.0≤ x ≤1.0，0.01≤ y ≤0.2，0.05≤z≤0.5。 2. The method for preparing short-wave infrared fluorescent ceramics according to claim 1, characterized in that: The parameters x y z The following conditions must be met: 0.0≤ x ≤0.5，0.01≤ y ≤0.1，0.05≤z≤0.5。 3. The method for preparing short-wave infrared fluorescent ceramics according to claim 2, characterized in that: The parameters x y z The following conditions must be met: 0.3≤ x ≤0.4，0.08≤ y ≤0.1，0.1≤z≤0.3。 4. The method for preparing short-wave infrared fluorescent ceramics according to claim 1, characterized in that, In step S3, the heat treatment time is 2~12 hours.

5. The method for preparing short-wave infrared fluorescent ceramics according to claim 1, characterized in that, In step S3, the heat treatment time is 4~10 hours.

6. The method for preparing short-wave infrared fluorescent ceramics according to claim 1, characterized in that, In step S3, the atmosphere is at least one of a mixture of nitrogen and hydrogen, a mixture of argon and hydrogen, and carbon monoxide.

7. An application of a short-wave infrared fluorescent ceramic, characterized in that, The application includes using the short-wave infrared fluorescent ceramic prepared by any one of claims 1-6 in a short-wave infrared emitting device.

8. The application of the short-wave infrared fluorescent ceramic according to claim 7, characterized in that, The short-wave infrared light-emitting device includes an excitation source and a light-emitting layer. The excitation source is selected from a blue LED chip, a laser diode, or an organic EL light-emitting device. The light-emitting layer includes the short-wave infrared fluorescent ceramic. The light-emitting device is prepared by directly covering the excitation source with the short-wave infrared fluorescent ceramic.

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