Cr < 3 + > ion doped transparent gamma-Al2O3 luminescent ceramic and preparation method thereof

Abstract

The invention provides a preparation method of a Cr < 3 + > ion doped transparent gamma-Al2O3 luminous nano ceramic, and provides the Cr < 3 + > ion doped transparent gamma-Al2O3 luminous nano ceramic prepared by the method, and when the incident wavelength exceeds 700nm, the light transmittance is greater than 66%. The preparation method comprises the following steps: firstly, adding 1g of AlCl3 and 0-0.01 g of CrCl3. 6H2O into 40mL of absolute ethyl alcohol, and uniformly mixing; pouring the mixed solution into a reaction kettle, and carrying out sealed heat preservation at 180 DEG C for 36 hours; after the reaction is finished, collecting a product, dispersing the product in absolute ethyl alcohol and centrifuging; spreading a colloidal product obtained by centrifugation in a culture dish, and drying at 60 DEG C for 12 hours; and putting the dried small blocks into a crucible, and calcining at 800 DEG C for 1 hour to obtain the Cr < 3 + > ion doped transparent gamma-Al2O3 luminous nano ceramic. The Cr < 3 + > ion doped transparent gamma-Al2O3 ceramic prepared by the invention is a block formed by interweaving nanoribbons, and the ceramic emits red fluorescence under the irradiation of 530nm green light.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of inorganic oxide transparent ceramics, and specifically relates to a Cr 3+ Ion-doped transparent γ-Al2O3 luminescent nanoceramics. Background Art

[0002] Transparent ceramics have the advantages of good light transmittance of glass and single crystal, and also have the properties of ceramics such as high temperature resistance and corrosion resistance, and have very broad application prospects. Since the advent of the first Al2O3 transparent ceramic "Lucalox" in the late 1950s, transparent ceramics have made significant progress in the past few decades and have been used in laser gain media, transparent armor, aerospace windows, solid-state lighting, magneto-optical materials and other fields. Generally speaking, materials with highly symmetrical crystal structures are easier to prepare transparent ceramics. Grains with low symmetry structures have optical anisotropy, which will cause birefringence and affect the transparency of the material. Therefore, most transparent ceramics have a cubic structure. γ-Al2O3 is the most common intermediate state of aluminum oxide. It belongs to the face-centered cubic lattice and can remain stable at low temperatures. In theory, it should be able to transmit light in a fairly large wavelength range (from deep ultraviolet to mid-infrared), but there are not many studies on γ-Al2O3 bulk transparent ceramics. In 2021, Beauvoir et al. prepared a translucent γ-AlOOH bulk at a uniaxial pressure of 500MPa and a temperature below 400°C, and then annealed it in ambient air at 500°C to produce a translucent γ-Al2O3 glass-ceramic material, but the resulting γ-Al2O3 glass-ceramic material contained an amorphous phase, and the actual online transmittance of the material was not given. In 2023, Chen et al. used a combination of homogeneous precipitation and high pressure to prepare bulk γ-Al2O3 transparent ceramics under the optimal conditions of 5GPa and 300°C. The Vickers hardness and compressive strength of the obtained ceramics were comparable to those of sapphire, and the maximum transmittance was 86%, proving that it is feasible to prepare highly transparent γ-Al2O3 bulk transparent ceramics with good mechanical properties. In 2024, Gao et al. used γ-Al2O3 powder as raw material and used cold sintering to prepare translucent ceramics with a transmittance of 16% at around 800nm.

[0003] Near-infrared light has strong penetrating power and can be absorbed by some molecular features. It can be widely used in plant growth, food analysis, medical imaging and other fields. Due to its unique atomic structure, the transition metal ion Cr 3+ Ion-doped materials have good luminescence effects in the near-infrared region and adjustable broadband luminescence, and show great application potential in the production of pc-LEDs, lighting and spectral analysis. Ruby (Cr 3+Chromium-doped aluminum oxide is one of the earliest laser materials. Existing chromium-doped near-infrared luminescent materials still have defects, such as low thermal quenching temperature, etc. There is an urgent need to develop more efficient, thermally stable, and longer-emission wavelength near-infrared luminescent materials. Summary of the invention

[0004] The technical problems to be solved by the present invention are:

[0005] 1. Provide a method for preparing Cr 3+ Method for ion-doped transparent γ-Al2O3 luminescent nanoceramics;

[0006] 2. Provide a Cr prepared by the above method 1. 3+ The ion-doped transparent γ-Al2O3 luminescent nano-ceramics have good optical transparency, and the doped ceramics have good photoluminescence effect in the range of 650-800nm.

[0007] The specific technical solutions of the present invention are as follows:

[0008] Anhydrous aluminum chloride, chromium chloride hexahydrate and anhydrous ethanol are used as raw materials. First, the anhydrous aluminum chloride and anhydrous ethanol are evenly mixed according to the ratio of one gram of anhydrous aluminum chloride to 40 mL of anhydrous ethanol; then 0-0.01 g of CrCl3·6H2O are weighed respectively and added to the mixed solution of anhydrous aluminum chloride and anhydrous ethanol, and mixed evenly; then the mixed solution is poured into a reactor, and sealed and kept warm at 180°C for 36 hours; after the reaction is completed, it is cooled naturally to room temperature, the product is collected and dispersed in anhydrous ethanol for centrifugation; the colloidal product obtained by centrifugation is spread flat in a petri dish, and dried at 60°C for 12 hours; the small pieces obtained by drying are put into a crucible, and calcined at 800°C for 1 hour to obtain Cr 3+ Ion-doped transparent γ-Al2O3 luminescent nano-ceramics. The molar ratios of CrCl3·6H2O and anhydrous AlCl3 are 0.2:99.8, 0.4:99.6, and 0.5:99.5 respectively.

[0009] The Cr prepared by the present invention 3+ The ion-doped transparent γ-Al2O3 luminescent nanoceramic is formed by interweaving and stacking nanobelts. The nanobelts are 50-100nm long, 5-30nm wide, and about 3nm thick. There are pores between the nanobelts, and the porosity is 60%-75%.

[0010] The Cr prepared by the present invention 3+ The ion-doped transparent γ-Al2O3 luminescent nanoceramics have good optical transparency and emit red fluorescence under 530nm green light. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1The bulk transparent γ-Al2O3 nano-ceramics and Cr prepared in Example 1, Example 2, Example 3 and Example 4 are 3+ Photo of ion-doped transparent γ-Al2O3 luminescent nanoceramics.

[0012] Figure 2 The bulk transparent γ-Al2O3 nano-ceramics and Cr prepared in Example 1, Example 2, Example 3 and Example 4 are 3+ Transmittance curve of ion-doped transparent γ-Al2O3 luminescent nanoceramics.

[0013] Figure 3 The bulk transparent γ-Al2O3 nano-ceramics and Cr prepared in Example 1, Example 2, Example 3 and Example 4 are 3+ XRD pattern of ion-doped transparent γ-Al2O3 luminescent nanoceramics.

[0014] Figure 4 The blocky transparent γ-Al2O3 nano-ceramics and Cr prepared in Example 1, Example 2 and Example 4 are 3+ Emission spectrum of ion-doped transparent γ-Al2O3 luminescent nanoceramics under excitation at a wavelength of 530nm.

[0015] Figure 5 The molar ratio of Cr in Example 2 is 0.2:99.8 3+ SEM image of ion-doped γ-Al2O3 luminescent ceramics. DETAILED DESCRIPTION

[0016] Example 1

[0017] With anhydrous aluminum chloride and anhydrous ethanol as raw materials, first weigh 1g of anhydrous aluminum chloride and add it into a beaker containing 40mL of anhydrous ethanol, and mix it evenly with a magnetic stirrer; then pour the mixed solution into a reactor, seal and keep warm at 180°C for 36 hours; after the reaction is completed, wait for it to cool naturally to room temperature, collect the product and disperse it in anhydrous ethanol by centrifugation; spread the colloidal product obtained by centrifugation in a culture dish, and dry it at 60°C for 12 hours; put the dried small pieces into a crucible, and calcine them at 800°C for 1 hour to obtain γ-Al2O3 transparent nanoceramics.

[0018] Figure 1 A photo of the γ-Al2O3 transparent nanoceramic prepared in Example 1 is given. The ceramic is a translucent block.

[0019] Figure 2The transmittance curve of the γ-Al2O3 transparent nanoceramic with a thickness of 0.5 mm prepared in Example 1 is given. The ceramic has high transparency in the long-wave direction. When the incident wavelength exceeds 550nm, the light transmittance is greater than 60%; when the incident wavelength exceeds 700nm, the light transmittance is greater than 76%.

[0020] Figure 3 The XRD pattern of the transparent γ-Al2O3 ceramic prepared in Example 1 is given, and the diffraction peak can be indexed to the cubic structure of γ-Al2O3.

[0021] Figure 4 The emission spectrum of the γ-Al2O3 nanoceramic prepared in Example 1 under excitation at a wavelength of 530 nm is given. The γ-Al2O3 nanoceramic has no emission peak in the range of 600-800 nm.

[0022] Example 2

[0023] Anhydrous aluminum chloride, chromium chloride hexahydrate and anhydrous ethanol are used as raw materials. First, 1 g of anhydrous aluminum chloride is weighed and added into a beaker containing 40 mL of anhydrous ethanol, and mixed evenly with a magnetic stirrer; then 0.004 g of CrCl3·6H2O is weighed and added into the mixed solution of anhydrous aluminum chloride and anhydrous ethanol, and mixed evenly; then the mixed solution is poured into a reactor, and sealed and kept warm at 180°C for 36 hours; after the reaction is completed, it is cooled naturally to room temperature, the product is collected and dispersed in anhydrous ethanol by centrifugation; the colloidal product obtained by centrifugation is spread flat in a petri dish and dried at 60°C for 12 hours; the dried small pieces are put into a crucible and calcined at 800°C for 1 hour to obtain Al 1.996 Cr 0.004 O3 transparent luminous ceramic.

[0024] Figure 1 The Al prepared in Example 2 is given. 1.996 Cr 0.004 Photo of O3 transparent luminescent ceramic, which is a yellow translucent block.

[0025] Figure 2 The Cr film with a molar ratio of 0.2:99.8 and a thickness of 0.5 mm prepared in Example 2 is given. 3+ The transmittance curve of ion-doped transparent γ-Al2O3 luminescent ceramics shows that the ceramics have high transparency in the long-wave direction. When the incident wavelength exceeds 550nm, the light transmittance is greater than 56%; when the incident wavelength exceeds 700nm, the light transmittance is greater than 72%.

[0026] Figure 3 The Cr prepared in Example 2 with a molar ratio of 0.2:99.8 is given. 3+The XRD diagram of ion-doped transparent γ-Al2O3 luminescent ceramics shows no extra diffraction peaks after doping, indicating that doping has not changed the crystal structure of the material.

[0027] Figure 4 The Cr prepared in Example 2 with a molar ratio of 0.2:99.8 is given. 3+ Emission spectrum of ion-doped transparent γ-Al2O3 luminescent ceramics under 530nm wavelength excitation. The ceramic has a broadband emission peak in the range of 650-800nm, with a peak value of 691nm.

[0028] Figure 5 The Cr prepared in Example 2 with a molar ratio of 0.2:99.8 is given. 3+ The SEM image of the ion-doped transparent γ-Al2O3 luminescent ceramic shows that the ceramic is made of interwoven and stacked nanobelts with nanopores between them.

[0029] This embodiment is the best embodiment.

[0030] Example 3

[0031] Anhydrous aluminum chloride, chromium chloride hexahydrate and anhydrous ethanol are used as raw materials. First, 1g of anhydrous aluminum chloride is weighed and added into a beaker containing 40mL of anhydrous ethanol, and mixed evenly with a magnetic stirrer; then 0.008g of CrCl3·6H2O is added into the mixed solution of anhydrous aluminum chloride and anhydrous ethanol, and mixed evenly; then the mixed solution is poured into a reactor, and sealed and kept warm at 180°C for 36 hours; after the reaction is completed, it is cooled naturally to room temperature, the product is collected and dispersed in anhydrous ethanol by centrifugation; the colloidal product obtained by centrifugation is spread flat in a petri dish and dried at 60°C for 12 hours; the small pieces obtained by drying are put into a crucible, and calcined at 800°C for 1 hour to obtain Al 1.992 Cr 0.008 O3 transparent luminous ceramic.

[0032] Figure 1 The Al prepared in Example 3 is given. 1.992 Cr 0.008 Photo of O3 transparent nanoceramics, the ceramic is a yellow translucent block.

[0033] Figure 2 The Cr film with a molar ratio of 0.4:99.6 and a thickness of 0.5 mm prepared in Example 3 is given. 3+ Transmittance curve of ion-doped transparent γ-Al2O3 luminescent ceramics. The ceramics have high transparency in the long-wave direction, but lower than that of undoped γ-Al2O3 transparent nanoceramics and Cr with a molar ratio of 0.2:99.8. 3+Doped γ-Al2O3 transparent nano-ceramics. When the incident wavelength exceeds 550nm, the light transmittance is greater than 46%; when the incident wavelength exceeds 700nm, the light transmittance is greater than 66%.

[0034] Figure 3 The Cr with a molar ratio of 0.4:99.6 prepared in Example 3 is given. 3+ The XRD diagram of ion-doped transparent γ-Al2O3 luminescent ceramics shows no extra diffraction peaks after doping, indicating that doping has not changed the crystal structure of the material.

[0035] Example 4

[0036] Anhydrous aluminum chloride, chromium chloride hexahydrate and anhydrous ethanol are used as raw materials. First, 1 g of anhydrous aluminum chloride is weighed and added into a beaker containing 40 mL of anhydrous ethanol, and mixed evenly with a magnetic stirrer; then 0.01 g of CrCl3·6H2O is weighed and added into the mixed solution of anhydrous aluminum chloride and anhydrous ethanol, and mixed evenly; then the mixed solution is poured into a reactor, and sealed and kept warm at 180°C for 36 hours; after the reaction is completed, it is cooled naturally to room temperature, the product is collected and dispersed in anhydrous ethanol by centrifugation; the colloidal product obtained by centrifugation is spread flat in a petri dish and dried at 60°C for 12 hours; the dried small pieces are put into a crucible and calcined at 800°C for 1 hour to obtain Al 1.990 Cr 0.010 O3 transparent nano ceramics.

[0037] Figure 1 The Al prepared in Example 4 is given. 1.990 Cr 0.010 Photo of O3 transparent nanoceramics, the ceramic is a yellow translucent block.

[0038] Figure 2 The Cr film with a molar ratio of 0.5:99.5 and a thickness of 0.5 mm prepared in Example 4 is given. 3+ The transmittance curve of the ion-doped transparent γ-Al2O3 luminescent ceramic shows that the ceramic has a higher transparency in the long-wave direction, but is lower than the transmittance obtained in the previous three embodiments. When the incident wavelength exceeds 550nm, the light transmittance is greater than 40%; when the incident wavelength exceeds 700nm, the light transmittance is greater than 66%.

[0039] Figure 3 The Cr with a molar ratio of 0.5:99.5 prepared in Example 4 is given. 3+ The XRD diagram of ion-doped transparent γ-Al2O3 luminescent ceramics shows no extra diffraction peaks after doping, indicating that doping has not changed the crystal structure of the material.

[0040] Figure 4The Cr with a molar ratio of 0.5:99.5 prepared in Example 4 is given. 3+ Emission spectrum of ion-doped transparent γ-Al2O3 luminescent ceramics under 530nm wavelength excitation. γ-Al2O3 nanoceramics has a broadband emission peak in the range of 650-800nm, with a peak at 691nm. The luminescence intensity is lower than that of Cr with a molar ratio of 0.2:99.8. 3+ Ion-doped γ-Al2O3 transparent nanoceramics.

Claims

1. A Cr 3+ Ion-doped transparent γ-Al2O3 luminescent ceramics, the chemical formula of the product is γ-Al 2-x Cr x O3(0≤x≤0.01).

2. A Cr according to claim 1 3+ Ion-doped transparent γ-Al2O3 luminescent ceramics, characterized in that: The ceramic is a block formed by interweaving nanobelts. The nanobelts are 50-100nm long, 5-30nm wide and about 3nm thick. There are pores between the nanobelts with a porosity of 60%-75%.

3. A Cr according to claim 1 3+ Ion-doped transparent γ-Al2O3 luminescent ceramics, characterized in that: Cr 3+ After ion doping, the ceramic can still maintain a high degree of transparency. When the incident wavelength exceeds 550nm, the light transmittance is greater than 40%; when the incident wavelength exceeds 700nm, the light transmittance is greater than 66%.

4. A Cr according to claim 1 3+ Ion-doped transparent γ-Al2O3 luminescent ceramics, characterized in that Cr 3+ The ion-doped transparent γ-Al2O3 luminescent ceramics have good photoluminescence properties in the range of 650-800nm, and the emission peak is located at 691nm.

5. A Cr 3+ The preparation method of ion-doped transparent γ-Al2O3 luminescent ceramics comprises the following steps: firstly, weighing 1g of anhydrous aluminum chloride and adding it into a beaker containing 40mL of anhydrous ethanol, and mixing it evenly with a magnetic stirrer; then weighing 0-0.01g of CrCl3·6H2O respectively and adding it into a mixed solution of anhydrous aluminum chloride and anhydrous ethanol, and mixing it evenly; then pouring the mixed solution into a reactor, sealing and keeping it warm at 180°C for 36 hours; after the reaction is completed, waiting for it to cool naturally to room temperature, collecting the product and dispersing it in anhydrous ethanol by centrifugation; spreading the colloidal product obtained by centrifugation in a petri dish, and drying it at 60°C for 12 hours; putting the dried small pieces into a crucible, and calcining them at 800°C for 1 hour to obtain Cr 3+ Ion-doped transparent γ-Al2O3 luminescent ceramics.

6. A Cr as claimed in claim 5 3+ A method for preparing ion-doped transparent γ-Al2O3 luminescent ceramics, characterized in that Cr The molar ratio of Cl3·6H2O to AlCl3 is 0:100-0.5:99.

5.

7. A Cr according to claim 5 3+ The method for preparing ion-doped transparent γ-Al2O3 luminescent ceramics is characterized in that The calcination temperature was 800°C and the calcination time was 1 hour.

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