Praseodymium ion doped bismuth germanate crystal material and preparation method and application thereof

Abstract

The invention discloses a praseodymium ion doped bismuth germanate crystal material and a preparation method and application thereof, and belongs to the technical field of photoelectric functions and lasers, and the molecular formula of the crystal is Pr4xBi4 (1-x) Ge3O12, wherein the value range of x is 0.005-0.02, x represents the doping concentration of Pr ions, and the Pr ions replace the lattice sites of Bi ions; the crystal system of the crystal material is a cubic crystal system, the space group is I-43d, the cell parameters are a = b = c = 10.524, alpha = beta = gamma = 90 degrees, V = 1165.63 and Z = 4, the crystal material has a cubic crystal system structure and isotropy, and efficient luminescence of 3P0 energy level of Pr < 3 + > ions is achieved by accurately controlling a crystal field.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of optoelectronic functional materials and laser technology, specifically referring to a praseodymium ion-doped bismuth germanate crystal material, its preparation method, and its application. Background Technology

[0002] Since the beginning of the 21st century, the maturity of semiconductor pumping technology has driven an urgent demand for high-performance, high-stability laser gain media. Among these, visible-light lasers have outstanding value in applications such as biological imaging, spectral analysis, and high-end displays, and trivalent praseodymium (Pr) ions... 3+ With its rich energy level structure and multi-band emission capability (covering blue, green, red and other bands), it is considered an ideal choice for realizing compact visible light lasers.

[0003] However, existing Pr 3+ Significant bottlenecks exist in doped material systems. While fluoride crystals (such as Pr:LiYF4) possess low phonon energy and high quantum efficiency, their poor mechanical strength and low thermal conductivity make them unsuitable for high-power applications. Anisotropic oxide crystals (such as Pr:YAlO3), despite their good thermomechanical properties, are hampered by excited-state absorption (ESA) effects, particularly resulting in a significant decrease in laser efficiency in the blue-green wavelength range. Current techniques have not yet been able to effectively optimize Pr in cubic symmetric matrices with superior overall performance. 3+ The energy level layout and transition processes of bismuth germanate (BGO). As a cubic crystal material, BGO possesses advantages such as high optical homogeneity, stable physicochemical properties, and mature preparation processes. Although it has been widely used in the field of scintillators, its systematic development into a Pr... 3+ Exploring the potential of doped laser gain media in the field of visible light lasers remains a research direction with significant scientific importance and promising application prospects. Summary of the Invention

[0004] To address the needs and challenges mentioned in the background, this invention provides a praseodymium ion-doped bismuth germanate crystal material, its preparation method, and its application, resulting in a novel laser crystal applicable to the intersection of optoelectronic functional materials and laser technology.

[0005] According to the technical solution of the present invention, a praseodymium ion-doped bismuth germanate crystal material is provided, comprising a matrix and dopant ions;

[0006] The matrix is ​​BGO crystal; wherein Bi2O3 accounts for 74.8% by mass and GeO2 accounts for 25.2% by mass.

[0007] The doped ion is Pr 3+ Based on the total molar amount of the matrix phase, Pr 3+ The doping concentration is 0.5~2 mol%

[0008] When excited by blue light in the 450-480 nm range, the crystal material exhibits strong emission across multiple wavelengths, covering characteristic wavelengths such as 484 nm, 612 nm, 646 nm, and 730 nm.

[0009] Preferably, the matrix contains 74.8% Bi2O3 and 25.2% GeO2 by mass.

[0010] Preferably, the Pr 3+ The doping concentration is 0.5~2 mol%.

[0011] Preferably, the crystal material 3 The P0 level exhibits highly efficient luminescence with a room-temperature fluorescence lifetime of 5.5-5.7 μs and a quantum efficiency ≥97%.

[0012] On the other hand, the present invention also provides a method for preparing the above-mentioned praseodymium ion-doped bismuth germanate crystal material, comprising the following steps:

[0013] (1) Raw material pretreatment: high-purity Pr6O 11 Powder, Bi2O3 powder, and GeO2 powder were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 , where x is the concentration of Pr ions doped in the melt;

[0014] (2) Molding: Weigh the mixed powder obtained in step (1), mix it evenly in an agate mortar, shape it into a rod, seal it, cold isostatically press it at 100 MP for 2 min, and then sinter it in air at 700℃ for 20 h. Place the sintered raw material in a crucible for later use.

[0015] (3) Crystal growth: The raw material treated in step 2) is placed into a platinum crucible, loaded into a micro-pull-down single crystal furnace, and then heated to melt in preparation for growth; the micro-pull-down speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is taken out.

[0016] Preferably, in step (1) Pr6O 11 The purity of the Bi2O3 is ≥99.999%, and the purity of the GeO2 is ≥99.999%.

[0017] Preferably, the cooling rate in step (3) is 10℃ / min.

[0018] Furthermore, the present invention also provides an application of the praseodymium ion-doped bismuth germanate crystal material described above in visible light lasers, the application scenarios including spectral analysis, laser medicine, precision laser processing, laser display, etc.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The crystal material of this invention exhibits strong multi-band emission under blue light excitation at 450-480 nm, covering characteristic wavelengths such as 484 nm, 612 nm, 646 nm and 730 nm, providing a new gain medium solution for the development of high-efficiency and compact visible light lasers, with broad application prospects.

[0021] Beneficial effects:

[0022] This invention achieves Pr by precisely controlling the crystal field. 3+ ion 3 The P0 level exhibits high-efficiency luminescence with a room-temperature fluorescence lifetime of 5.5-5.7 μs and a quantum efficiency of ≥97%. Under blue light excitation at 450-480 nm, the crystal displays strong emission across multiple wavelengths, covering characteristic wavelengths such as 484 nm, 612 nm, 646 nm, and 730 nm.

[0023] This invention employs a micro-pull-down (μ-PD) growth technique, using high-purity raw materials grown along a path in an air atmosphere. <210> Crystal orientation growth can produce optically uniform crystal fibers with controllable diameter, which are suitable for large-scale production. Attached Figure Description

[0024] Figure 1 This is a sample spectrum from Example 1 of the present invention;

[0025] Figure 2 This is the absorption spectrum of Example 1 of the present invention;

[0026] Figure 3 The emission spectrum of Embodiment 1 of the present invention;

[0027] Figure 4 This refers to the energy level lifetime of Embodiment 1 of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection.

[0029] This invention provides a praseodymium ion-doped bismuth germanate crystal material, comprising a matrix and dopant ions;

[0030] The matrix is ​​BGO crystal; wherein Bi2O3 accounts for 74.8% by mass and GeO2 accounts for 25.2% by mass.

[0031] The doped ion is Pr 3+ Based on the total molar amount of the matrix phase, Pr 3+ The doping concentration is 0.5~2 mol%

[0032] When excited by blue light in the 450-480 nm range, the crystal material exhibits strong emission across multiple wavelengths, covering characteristic wavelengths such as 484 nm, 612 nm, 646 nm, and 730 nm.

[0033] The matrix contains 74.8% Bi2O3 and 25.2% GeO2 by mass.

[0034] The Pr 3+ The doping concentration is 0.5~2 mol%.

[0035] The crystal material 3 The P0 level exhibits highly efficient luminescence with a room-temperature fluorescence lifetime of 5.5-5.7 μs and a quantum efficiency ≥97%.

[0036] On the other hand, the present invention also provides a method for preparing the above-mentioned praseodymium ion-doped bismuth germanate crystal material, comprising the following steps:

[0037] (1) Raw material pretreatment: high-purity Pr6O 11 Powder, Bi2O3 powder, and GeO2 powder were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 , where x is the concentration of Pr ions doped in the melt;

[0038] (2) Molding: Weigh the mixed powder obtained in step (1), mix it evenly in an agate mortar, shape it into a rod, seal it, cold isostatically press it at 100 MP for 2 min, and then sinter it in air at 700℃ for 20 h. Place the sintered raw material in a crucible for later use.

[0039] (3) Crystal growth: The raw material treated in step 2) is placed into a platinum crucible, loaded into a micro-pull-down single crystal furnace, and then heated to melt in preparation for growth; the micro-pull-down speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is taken out.

[0040] Example 1

[0041] Pr6O 11High-purity raw materials of Bi₂O₃ and GeO₂ (purity ≥ 99.999%) were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 Where x is the concentration of Pr ions doped in the melt, in this example x=0.005, and the total weight is 10 g. After weighing, the raw materials are mixed evenly in an agate mortar, shaped into rods, sealed, and cold isostatically pressed at 100 MPa for 2 min. Then, they are sintered in air at 700℃ for 20 h. The sintered raw materials are placed in a crucible for later use. Using zirconium oxide as a heat preservation cover, the treated raw materials are placed in a platinum crucible, loaded into a micro-pulling furnace, and then heated to melt in preparation for growth; the micro-pulling speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is removed.

[0042] Example 2

[0043] Pr6O 11 High-purity raw materials of Bi₂O₃ and GeO₂ (purity ≥ 99.999%) were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 Where x is the concentration of Pr ions doped in the melt, in this example x=0.0075, and the total weight is 10 g. After weighing, the raw materials are mixed evenly in an agate mortar, shaped into rods, sealed, and cold isostatically pressed at 100 MPa for 2 min. Then, they are sintered in air at 700℃ for 20 h. The sintered raw materials are placed in a crucible for later use. Using zirconium oxide as a heat preservation cover, the treated raw materials are placed in a platinum crucible, loaded into a micro-pulling furnace, and then heated to melt in preparation for growth; the micro-pulling speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is removed.

[0044] Example 3

[0045] Pr6O 11 High-purity raw materials of Bi₂O₃ and GeO₂ (purity ≥ 99.999%) were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 Where x is the concentration of Pr ions doped in the melt, in this embodiment x=0.010, and the total weight is 10 g. After weighing, the raw materials are mixed evenly in an agate mortar, shaped into rods, sealed, and cold isostatically pressed at 100 MPa for 2 min. Then, they are sintered in air at 700 °C for 20 h. The sintered raw materials are placed in a crucible for later use. Using zirconium oxide as a heat preservation cover, the treated raw materials are placed in a platinum crucible, loaded into a micro-pulling furnace, and then heated to melt in preparation for growth; the micro-pulling speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is removed.

[0046] Example 4

[0047] Pr6O 11 High-purity raw materials of Bi₂O₃ and GeO₂ (purity ≥ 99.999%) were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 Where x is the concentration of Pr ions doped in the melt, in this example x=0.0125, and the total weight is 10 g. After weighing, the raw materials are mixed evenly in an agate mortar, shaped into rods, sealed, and cold isostatically pressed at 100 MPa for 2 min. Then, they are sintered in air at 700℃ for 20 h. The sintered raw materials are placed in a crucible for later use. Using zirconium oxide as a heat preservation cover, the treated raw materials are placed in a platinum crucible, loaded into a micro-pulling furnace, and then heated to melt in preparation for growth; the micro-pulling speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is removed.

[0048] Example 5

[0049] Pr6O 11 High-purity raw materials of Bi₂O₃ and GeO₂ (purity ≥ 99.999%) were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 Where x is the concentration of Pr ions doped in the melt, in this example x=0.015, and the total weight is 10 g. After weighing, the raw materials are mixed evenly in an agate mortar, shaped into rods, sealed, and cold isostatically pressed at 100 MPa for 2 min. Then, they are sintered in air at 700℃ for 20 h. The sintered raw materials are placed in a crucible for later use. Using zirconium oxide as a heat preservation cover, the treated raw materials are placed in a platinum crucible, loaded into a micro-pulling furnace, and then heated to melt in preparation for growth; the micro-pulling speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is removed.

[0050] Example 6

[0051] Pr6O 11 High-purity raw materials of Bi₂O₃ and GeO₂ (purity ≥ 99.999%) were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12Where x is the concentration of Pr ions doped in the melt, in this example x=0.020, and the total weight is 10 g. After weighing, the raw materials are mixed evenly in an agate mortar, shaped into rods, sealed, and cold isostatically pressed at 100 MPa for 2 min. Then, they are sintered in air at 700℃ for 20 h. The sintered raw materials are placed in a crucible for later use. Using zirconium oxide as a heat preservation cover, the treated raw materials are placed in a platinum crucible, loaded into a micro-pulling furnace, and then heated to melt in preparation for growth; the micro-pulling speed is 0.3 mm / min. After the crystal growth is completed, it is slowly cooled to room temperature and the crystal is removed.

[0052] In summary, by precisely controlling the crystal field, this invention achieves Pr 3+ ion 3 The P0 level exhibits highly efficient luminescence with a room-temperature fluorescence lifetime of 5.5-5.7 μs and a quantum efficiency of ≥97%.

[0053] When excited by blue light in the 450-480nm range, the crystal exhibits strong emission across multiple wavelengths, covering characteristic wavelengths such as 484nm, 612nm, 646nm, and 730nm.

[0054] Verified by Judd-Ofelt theory, this crystal exhibits an emission cross-section of up to 5.4 × 10⁻⁶ at 646 nm. -19 cm 2 Its performance is superior to mainstream materials.

[0055] In terms of preparation, the micro-pull-down (μ-PD) growth technique was adopted, using high-purity raw materials grown in an air atmosphere. <210> Crystalline growth allows for the production of optically uniform crystal fibers with controllable diameters, making them suitable for mass production. This crystal material provides a novel gain medium solution for developing high-efficiency, compact visible light lasers, with broad application prospects.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A praseodymium ion-doped bismuth germanate crystal material, characterized in that, The molecular formula of the crystal is Pr 4x Bi 4(1-x) Ge3O 12 ; Wherein, x ranges from 0.005 to 0.02, and x represents the doping concentration of Pr ions, where Pr ions replace Bi ion lattice sites; the crystal system of the described crystal material is cubic, with space group I-43d, and cell parameters a=b=c=10.524 Å, α=β=γ=90°, and V=1165.6 Å. 3 Z=4.

2. The praseodymium ion-doped bismuth germanate crystal material according to claim 1, characterized in that, The Pr 3+ The doping concentration is 0.5~2 mol%.

3. The praseodymium ion-doped bismuth germanate crystal material according to claim 1, characterized in that, The material 3 The P0 level exhibits highly efficient luminescence with a room-temperature fluorescence lifetime of 5.5-5.7 μs and a quantum efficiency ≥97%.

4. A method for preparing praseodymium ion-doped bismuth germanate crystal material according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Raw material pretreatment: high-purity Pr6O 11 Powder, Bi2O3 powder, and GeO2 powder were weighed according to the general chemical formula: Pr 4x Bi 4(1-x) Ge3O 12 , where x is the concentration of Pr ions doped in the melt; (2) Molding: Weigh the mixed powder obtained in step (1), mix it evenly in an agate mortar, shape it into a rod, seal it, cold isostatically press it, and then sinter it in air. After sintering, place it in a crucible for later use. (3) Crystal growth: The raw material treated in step (2) is placed into a platinum crucible, loaded into a micro-pull-down single crystal furnace, and then heated to melt in preparation for growth; after the crystal growth is completed, it is slowly cooled to room temperature and the crystal is taken out.

5. The method for preparing praseodymium ion-doped bismuth germanate crystal material according to claim 4, characterized in that, In step (1), Pr6O 11 The purity of the Bi2O3 is ≥99.999%, and the purity of the GeO2 is ≥99.999%.

6. The method for preparing praseodymium ion-doped bismuth germanate crystal material according to claim 4, characterized in that, The cold isostatic pressing in step (2) specifically refers to cold isostatic pressing at 100 MPa for 2 minutes.

7. The method for preparing praseodymium ion-doped bismuth germanate crystal material according to claim 4, characterized in that, The sintering in step (2) specifically involves sintering in air at 700°C for 20 hours.

8. The method for preparing praseodymium ion-doped bismuth germanate crystal material according to claim 4, characterized in that, The micro-pulling speed of the raw material in step (3) in the micro-pulling furnace is 0.3 mm / min.

9. The application of a praseodymium ion-doped bismuth germanate crystal material according to any one of claims 1-3 in a visible light laser, characterized in that: The application scenarios include spectral analysis, laser medicine, precision laser processing, and laser display.

10. A gain medium for a visible laser, characterized in that: The gain medium is the praseodymium-doped bismuth germanate crystal material as described in any one of claims 1-3. Under blue light excitation at 450-480nm, the crystal exhibits strong emission across multiple wavelengths, covering characteristic wavelengths such as 484nm, 612nm, 646nm, and 730nm.

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