Polymorphic nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate and preparation and application thereof

Abstract

The present application relates to 3-amino-1,2,4-triazole nitrate polymorphic nonlinear optical crystal material and its preparation and application, the chemical formula of the polymorphic material is (C2H5N4)(NO3), the molecular weight is 147.11, specifically includes two kinds of crystal forms: (1) alpha-(C2H5N4)(NO3) belongs to triclinic system, space group is P1, cell parameter is alpha=110.44~114.63°, (2) beta=93.04~97.71°, gamma=93.49~97.64°, Z=2, the cell volume is compared with prior art, the polymorphic alpha-(C2H5N4)(NO3) and beta-(C2H5N4)(NO3) material involved in the present application has larger frequency doubling effect at 1064nm, and both can realize phase matching.In addition, the ultraviolet absorption cutoff edge of the crystal material is 240nm and 248nm respectively, has wide application prospect in the field of photoelectric technology such as laser frequency conversion, high-speed optical signal modulation, holographic storage system.

Description

Technical Field

[0001] This invention belongs to the field of nonlinear optical crystal materials technology, and relates to polycrystalline nonlinear optical crystal materials of 3-amino-1,2,4-triazole nitrate, as well as their preparation and application. Background Technology

[0002] Second-order nonlinear optical crystals, as key optoelectronic functional materials, are characterized by their frequency doubling effect (SHG), a property that makes them valuable for applications in frequency doubling devices, electro-optic modulators, and holographic storage elements. Currently, widely used nonlinear optical crystals include KH₂PO₄ (KDP), LiB₃O₅ (LBO), and β-BaB₂O₄ (BBO). With the rapid development of ultraviolet laser technology in high-end fields such as microfabrication, high-density storage, and photolithography, the development of frequency doubling crystals suitable for the ultraviolet band has become a frontier in materials science research. However, how to synergistically optimize the constraints between optical bandgap, frequency doubling effect, and birefringence remains a core challenge in the development of ultraviolet frequency doubling materials. This invention patent is proposed precisely to address these challenges. Summary of the Invention

[0003] The present invention aims to provide a polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate with a large frequency doubling effect, wide ultraviolet transmittance and moderate birefringence, as well as its preparation method and application.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] One of the technical solutions of the present invention provides a polymorphic nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate, which includes two crystal forms: α-(C2H5N4)(NO3) and β-(C2H5N4)(NO3).

[0006] Furthermore, for 3-amino-1,2,4-triazole nitrate in crystal form α, its chemical formula is (C2H5N4)(NO3), its molecular weight is 147.11, it crystallizes in the triclinic crystal system, space group P1, and its unit cell parameters are... α = 110.44–114.63°, β = 93.04–97.71°, γ = 93.49–97.64°, Z = 2, cell volume is

[0007] The crystal structure of the α-phase 3-amino-1,2,4-triazole nitrate is as follows: anion (NO3). - The elementary unit is bonded to four adjacent (C2H5N4) atoms through hydrogen bonding. +The layers connect to form a two-dimensional van der Waals layered structure. Adjacent two-dimensional layers are stacked parallel to each other on the bc surface in a -A1A1A1A1- stacking pattern through van der Waals force interactions, ultimately forming a pseudo-three-dimensional structure. Figure 1 ).

[0008] Furthermore, for 3-amino-1,2,4-triazole nitrate, crystal form β has the chemical formula (C2H5N4)(NO3), a molecular weight of 147.11, crystallizes in a monoclinic system with space group P21 and cell parameters of [missing information]. β = 88.32–92.14°, Z = 8, cell volume is

[0009] The crystal structure of the β-phase 3-amino-1,2,4-triazole nitrate is as follows: anion (NO3). - The elementary unit is bonded to four adjacent (C2H5N4) atoms through hydrogen bonding. + Bridges connect the layers, forming a two-dimensional van der Waals layered structure; adjacent two-dimensional layers are stacked parallel to each other on the bc surface in a -A1A2A3A4- stacking pattern through van der Waals force interactions, ultimately forming a pseudo-three-dimensional structure. Figure 9 ).

[0010] The second technical solution of the present invention provides a method for preparing a polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate, wherein...

[0011] For α-phase 3-amino-1,2,4-triazole nitrate, it is prepared by slow evaporation of aqueous solution. The raw materials containing organic source, inorganic source and water are mixed and placed in an open evaporating dish for slow evaporation to obtain colorless and transparent flaky crystals, which is the target product.

[0012] Furthermore, in the raw materials, the molar ratio of organic source, inorganic source and water is 10:(10-60):(500-1250). Preferably, the molar ratio of organic source, inorganic source and water is 10:(10-30):(700-1050).

[0013] Furthermore, the crystallization temperature is 10℃~45℃. Preferably, the crystallization temperature is 15℃~30℃.

[0014] Furthermore, the crystallization time is no less than 7 days. Preferably, the crystallization time is 14 to 21 days.

[0015] Furthermore, the organic source is 3-amino-1,2,4-triazole.

[0016] Furthermore, the inorganic source is nitric acid.

[0017] For β-phase 3-amino-1,2,4-triazole nitrate, it is prepared by slow evaporation of aqueous solution. The raw materials containing organic source, inorganic source and water are mixed and placed in an open evaporating dish for slow evaporation to obtain colorless and transparent flaky crystals, which is the target product.

[0018] Furthermore, in the raw materials, the molar ratio of organic source, inorganic source and water is 10:(70-120):(500-1250). Preferably, the molar ratio of organic source, inorganic source and water is 10:(90-100):(700-1050).

[0019] Furthermore, the crystallization temperature is 10℃~45℃. Preferably, the crystallization temperature is 15℃~30℃.

[0020] Furthermore, the crystallization time is no less than 7 days. Preferably, the crystallization time is 14 to 21 days.

[0021] Furthermore, the organic source is 3-amino-1,2,4-triazole.

[0022] Furthermore, the inorganic source is nitric acid.

[0023] The third technical solution of the present invention provides the application of 3-amino-1,2,4-triazole nitrate second-order nonlinear optical crystal material in laser frequency converters, optical parametric oscillators, optical parametric amplifiers and photoelectric rectifiers.

[0024] Furthermore, this second-order nonlinear optical crystal material can be used in laser frequency converters, which can output 532nm laser under 1064nm laser irradiation. The powder frequency doubling intensities of α-(C2H5N4)(NO3) and β-(C2H5N4)(NO3) are 3.50 times and 1.00 times that of KDP crystal, respectively, and both can achieve phase matching.

[0025] This invention proposes two methods for π-conjugated planar unit composites, and successfully prepares two polycrystalline phases of 3-amino-1,2,4-triazole nitrate (α-,β-(C2H5N4)(NO3)) using a slow evaporation technique in aqueous solution. Among them, α-,β-(C2H5N4)(NO3) possesses strong frequency doubling effect (3.5×KDP(α-(C2H5N4)(NO3)), 1.0×KDP(β-(C2H5N4)(NO3))), wide band gap (5.17eV(α-(C2H5N4)(NO3), 5.00eV(β-(C2H5N4)(NO3))), and moderate birefringence (0.069(α-(C2H5N4)(NO3)), 0.046(β-(C2H5N4)(NO3))). They have important application potential in the field of ultraviolet laser frequency doubling crystal devices.

[0026] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects:

[0027] (1) This application provides for the first time two polymorphs of 3-amino-1,2,4-triazole nitrate and their use as second-order nonlinear optical crystal materials. Both α-(C2H5N4)(NO3) and β-(C2H5N4)(NO3) crystal materials exhibit significant frequency doubling effects, 3.5 times and 1 times that of KDP crystals, respectively, and can achieve phase matching. Furthermore, the ultraviolet transmission absorption cutoff edges of these crystal materials reach 240 nm and 248 nm, respectively. Both crystal materials demonstrate significant application potential in the field of nonlinear optics.

[0028] (2) This application provides a method for preparing the above-mentioned crystal material, which uses a slow evaporation method with aqueous solution to prepare 3-amino-1,2,4-triazole nitrate crystals. By precisely controlling the ratio of starting materials, high-purity controllable synthesis of different crystal phases is achieved. This method has the advantages of mild synthesis conditions, high yield, and easy crystal growth, and can obtain millimeter-scale single crystals with high optical quality and excellent purity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the crystal structure of α-(C2H5N4)(NO3);

[0030] Figure 2 The X-ray diffraction pattern of sample 1-1# obtained by fitting the crystal structure resolved by single-crystal X-ray diffraction is compared with the X-ray diffraction pattern obtained by grinding sample 1-1# into powder.

[0031] Figure 3 This is the ultraviolet-visible-near-infrared transmission spectrum of sample 1-1#;

[0032] Figure 4 This is the infrared spectrum of sample 1-1#;

[0033] Figure 5 This is the thermogravimetric analysis chromatogram of sample 1-1#;

[0034] Figure 6 The second harmonic signal diagrams of sample 1-1# and standard KDP within the size range of 200-280μm are shown.

[0035] Figure 7 This is the second harmonic phase matching diagram of sample 1-1# in the 1064nm band;

[0036] Figure 8These are birefringence test images, where (a) is the image of α-(C2H5N4)(NO3) before extinction; (b) is the image of α-(C2H5N4)(NO3) after complete extinction; and (c) is the crystal thickness of α-(C2H5N4)(NO3).

[0037] Figure 9 This is a schematic diagram of the crystal structure of β-(C2H5N4)(NO3);

[0038] Figure 10 The X-ray diffraction pattern of sample 2-1# obtained by fitting the crystal structure resolved by single-crystal X-ray diffraction is compared with the X-ray diffraction pattern obtained by grinding sample 2-1# into powder.

[0039] Figure 11 This is the ultraviolet-visible-near-infrared transmission spectrum of sample 2-1#;

[0040] Figure 12 This is the infrared spectrum of sample 2-1#;

[0041] Figure 13 This is the thermogravimetric analysis chromatogram of sample 2-1#;

[0042] Figure 14 These are the second harmonic signal diagrams of sample 2-1# and standard sample KDP within the size range of 200–280 μm;

[0043] Figure 15 This is the second harmonic phase matching diagram of sample 2-1# in the 1064nm band;

[0044] Figure 16 These are images from birefringence tests, where (a) is an image of β-(C2H5N4)(NO3) before extinction; (b) is an image of β-(C2H5N4)(NO3) after complete extinction; and (c) shows the crystal thickness of β-(C2H5N4)(NO3).

[0045] Figure 17 This is a schematic diagram of the crystal structures of α-(C2H5N4)(NO3) and β-(C2H5N4)(NO3). Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0047] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0048] Example 1

[0049] (1) Preparation of samples 1-1# to 1-8#

[0050] An organic source (3-amino-1,2,4-triazole), an inorganic source (nitric acid), and water were mixed in a certain proportion to form a raw material. The mixture was placed in an open evaporating dish, and the aqueous solution was slowly evaporated at the crystallization temperature. After filtration, washing, and drying, colorless flaky α-(C2H5N4)(NO3) crystal samples were obtained. The relationship between the types and proportions of raw materials in the initial mixture, the crystallization temperature, the crystallization time, and the sample number is shown in Table 1.

[0051] (2) Crystal structure analysis of the sample

[0052] The structures of samples 1-1# to 1-8# were analyzed using single-crystal X-ray diffraction and powder X-ray diffraction methods.

[0053] Single-crystal X-ray diffraction was performed using a Bruker D8 VENTURE CMOS X-ray single-crystal diffractometer (Germany). The crystal size was 0.44 × 0.18 × 0.09 mm. 3 The data collection temperature was 293 K, and the diffraction source was graphite-monochromatic Mo-Kα rays. The scanning mode was ω; the data underwent absorption correction processing using the Multi-Scan method. Structural analysis was performed using the SHELXTL-97 package; the positions of heavy atoms were determined using a direct method, and the coordinates of the remaining atoms were obtained using difference Fourier synthesis; F-based... 2 The full matrix least squares method is used to refine the coordinates and anisotropic thermal parameters of all atoms.

[0054] Table 1. Relationship between sample synthesis conditions and sample number

[0055]

[0056] Single-crystal X-ray diffraction results showed that samples 1-1# to 1-8# had the same chemical formula and crystal structure, with the chemical formula α-(C2H5N4)(NO3), a molecular weight of 147.11, and crystallized in the triclinic crystal system with space group P1 and unit cell parameters of [missing information]. α = 110.44–114.63°, β = 93.04–97.71°, γ = 93.49–97.64°, Z = 2, cell volume is

[0057] Taking sample 1-1# as a typical example, its crystal structure data is as follows: α = 112.131(16)°, β = 95.625(19)°, γ = 95.861(18)°, Z = 2, cell volume is Its crystal structure is as follows Figure 1 As shown.

[0058] Powder X-ray diffraction was performed on a Bruker D8 X-ray powder diffractometer from Bruker GmbH, Germany. The test conditions were a fixed target, a monochromatic Cu-Kα light source, and a wavelength of [missing information]. The voltage and current are 40kV / 20A, the slits DivSlit / RecSlit / SctSlit are 2.00deg / 0.3mm / 2.00deg respectively, the scanning range is 5~70°, and the scanning step size is 0.02°.

[0059] Powder X-ray diffraction results show that the diffraction peaks of samples 1-1# to 1-8# are in the same positions as the diffraction peaks fitted by single crystal data on the XRD pattern.

[0060] Taking sample 1-1# as a typical example, such as Figure 2 As shown, the X-ray diffraction pattern obtained by fitting the crystal structure determined by single-crystal X-ray diffraction is consistent with the X-ray diffraction pattern obtained after grinding sample 1-1# into powder, showing consistent peak positions and intensities. This indicates that the obtained sample has high purity.

[0061] (3) Ultraviolet-Visible-NearInfrared Spectroscopy Test

[0062] The UV-Vis transmission spectroscopy of samples 1-1# was measured using an Agilent Technologies Carry 5000 UV-Vis-NIR spectrophotometer. The results are as follows: Figure 3 As shown, the ultraviolet absorption cutoff edge of this compound is 240 nm, and the optical band gap is 5.17 eV.

[0063] (4) Infrared spectroscopy test

[0064] The infrared spectra of samples 1-1# were measured using a Nicolet iS10 Fourier transform infrared spectrometer from Thermo Fisher Scientific, Inc., USA. The results are as follows: Figure 4 As shown, the characteristic absorption peaks in the infrared spectrum confirm the accuracy of the crystal structure.

[0065] (5) Thermogravimetric test

[0066] Thermogravimetric analysis (TGA) of samples 1-1# was performed using a TGA / DSC1 / 1100SF thermogravimetric analyzer from Mettler Toledo International Trading (Shanghai) Co., Ltd. The results are as follows: Figure 5 As shown, the thermal decomposition temperature of this compound is 178℃.

[0067] (6) Frequency doubling test experiment and results

[0068] The frequency doubling test experiment for sample 1-1# is as follows: A Q-switched Nd:YAG solid-state laser with a wavelength of 1064nm was used as the fundamental frequency light to irradiate the test crystal powder. A photomultiplier tube was used to detect the generated second harmonic at 532nm, and the harmonic intensity was displayed on an oscilloscope. The test crystal sample and the standard KDP crystal were ground separately, and crystals of different particle sizes were separated using a standard sieve. The particle size ranges were less than 50–74, 74–105, 105–150, 150–200, and 200–280μm, respectively. The trend of the frequency doubling signal with particle size was observed to determine whether phase matching could be achieved. Under the same test conditions, the intensity of the second harmonic generated by the sample was compared with that generated by the reference crystal KDP to obtain the relative magnitude of the sample's frequency doubling effect.

[0069] Test results show that the α-(C2H5N4)(NO3) crystal exhibits a strong powder frequency doubling effect. Under 1064nm wavelength laser irradiation, its frequency doubling intensity is 3.50 times that of the KDP crystal. Figure 6 ), and can achieve phase matching ( Figure 7 ).

[0070] (7) Birefringence experiment and results

[0071] The birefringence test of sample 1-1# was conducted as follows: The optical path difference and crystal thickness of a specific crystal plane were obtained using a ZEISS AxioScope 5 polarizing microscope equipped with a Berek compensator under a 546nm light source. According to the formula R=|N eˉ N o |×T=Δn×T determines birefringence, the optical path difference is R, the measured birefringence is Δn, and the crystal thickness is T.

[0072] Test results show that, Figure 8 In α, α-(C2H5N4)(NO3) did not undergo extinction; while in α... Figure 8 In b, the crystal is completely extinct, and the optical path difference is 2.30 μm. For example... Figure 8 As shown in Figure c, the crystal thickness of α-(C2H5N4)(NO3) is 33.419 μm. Using the formula R = Δn × T, the birefringence of this crystal is calculated to be 0.069.

[0073] Example 2

[0074] (1) Preparation of samples 2-1# to 2-8#

[0075] Table 2. Relationship between sample synthesis conditions and sample number

[0076]

[0077] An organic source (3-amino-1,2,4-triazole), an inorganic source (nitric acid), and water were mixed in a certain proportion to form a raw material. The mixture was placed in an open evaporating dish, and the aqueous solution was slowly evaporated at the crystallization temperature. After filtration, washing, and drying, colorless, blocky β-(C2H5N4)(NO3) crystal samples were obtained. The relationship between the types and proportions of raw materials in the initial mixture, the crystallization temperature, the crystallization time, and the sample number is shown in Table 2.

[0078] (2) Crystal structure analysis of the sample

[0079] The structures of samples 2-1# to 2-8# were analyzed using single-crystal X-ray diffraction and powder X-ray diffraction methods.

[0080] Single-crystal X-ray diffraction was performed using a Bruker D8 VENTURE CMOS X-ray single-crystal diffractometer (Germany). The crystal size was 0.32 × 0.27 × 0.11 mm. 3 The data collection temperature was 293 K, and the diffraction source was graphite-monochromatic Mo-Kα rays. The scanning mode was ω; the data underwent absorption correction processing using the Multi-Scan method. Structural analysis was performed using the SHELXTL-97 package; the positions of heavy atoms were determined using a direct method, and the coordinates of the remaining atoms were obtained using difference Fourier synthesis; F-based... 2 The full matrix least squares method is used to refine the coordinates and anisotropic thermal parameters of all atoms.

[0081] Single-crystal X-ray diffraction results showed that samples 2-1# to 2-8# had the same chemical formula and crystal structure, with the chemical formula β-(C2H5N4)(NO3), a molecular weight of 147.11, belonging to the monoclinic crystal system, space group P21, and cell parameters of [missing information]. β = 88.32–92.14°, Z = 8, cell volume is

[0082] Taking sample 2-1# as a typical example, its crystal structure data is as follows: β=90.381(3)°, Z=8, cell volume is Its crystal structure is as follows Figure 9 As shown.

[0083] Powder X-ray diffraction was performed on a Bruker D8 X-ray powder diffractometer from Bruker GmbH, Germany. The test conditions were a fixed target, a monochromatic Cu-Kα light source, and a wavelength of [missing information]. The voltage and current are 40kV / 20A, the slits DivSlit / RecSlit / SctSlit are 2.00deg / 0.3mm / 2.00deg respectively, the scanning range is 5~70°, and the scanning step size is 0.02°.

[0084] Powder X-ray diffraction results show that the diffraction peaks of samples 2-1# to 2-8# are in the same positions as the diffraction peaks fitted by single crystal data on the XRD patterns.

[0085] Taking sample 2-1# as a typical example, such as Figure 10 As shown, the X-ray diffraction pattern obtained by fitting the crystal structure determined by single-crystal X-ray diffraction is consistent with the X-ray diffraction pattern obtained after grinding sample 2-1# into powder, showing consistent peak positions and intensities. This indicates that the obtained sample has high purity.

[0086] (3) Ultraviolet-Visible-NearInfrared Spectroscopy Test

[0087] The UV-Vis transmission spectrum of sample 2-1# was measured using an Agilent Technologies Carry 5000 UV-Vis-NIR spectrophotometer. The results are as follows: Figure 11 As shown, the ultraviolet absorption cutoff edge of this compound is 248 nm, and the optical band gap is 5.00 eV.

[0088] (4) Infrared spectroscopy test

[0089] The infrared spectra of sample 2-1# were measured using a Nicolet iS10 Fourier transform infrared spectrometer from Thermo Fisher Scientific, Inc., USA. The results are as follows: Figure 12 As shown, the characteristic absorption peaks in the infrared spectrum confirm the accuracy of the crystal structure.

[0090] (5) Thermogravimetric test

[0091] Thermogravimetric analysis (TGA) of sample 2-1# was performed using a TGA / DSC1 / 1100SF thermogravimetric analyzer from Mettler Toledo International Trading (Shanghai) Co., Ltd. The results are as follows: Figure 13 As shown, the thermal decomposition temperature of this compound is 176℃.

[0092] (6) Frequency doubling test experiment and results

[0093] The frequency doubling test experiment for sample 2-1# is as follows: A 1064nm wavelength laser generated by a Q-switched Nd:YAG solid-state laser was used as the fundamental frequency light to irradiate the test crystal powder. The generated 532nm second harmonic was detected using a photomultiplier tube, and the harmonic intensity was displayed using an oscilloscope. The test crystal sample and the standard KDP crystal were ground separately, and crystals of different particle sizes were separated using a standard sieve, with particle size ranges of less than 50–74, 74–105, 105–150, 150–200, and 200–280μm, respectively. The trend of the frequency doubling signal with particle size was observed to determine whether phase matching could be achieved. Under the same test conditions, the intensity of the second harmonic generated by the sample was compared with the intensity of the second harmonic generated by the reference crystal KDP to obtain the relative magnitude of the frequency doubling effect of the sample.

[0094] Test results show that the β-(C2H5N4)(NO3) crystal exhibits a strong powder frequency doubling effect. Under 1064nm wavelength laser irradiation, its frequency doubling intensity is 1.00 times that of the KDP crystal. Figure 14 ), and can achieve phase matching ( Figure 15 ).

[0095] (7) Birefringence experiment and results

[0096] The birefringence test of sample 2-1# is as follows:

[0097] The optical path difference and crystal thickness of a specific crystal plane were obtained using a ZEISS Axio Scope 5 polarizing microscope equipped with a Berek compensator under a 546 nm light source. The formula R = |N eˉ N o |×T=Δn×T determines birefringence, the optical path difference is R, the measured birefringence is Δn, and the crystal thickness is T.

[0098] Test results show that, Figure 16 In a, β-(C2H5N4)(NO3) did not undergo extinction; in Figure 16 In b, the crystal is completely extinct, and the optical path difference is 1.88 μm. For example... Figure 16 As shown in Figure c, the crystal thickness of β-(C2H5N4)(NO3) is 40.708 μm. Using the formula R = Δn × T, the birefringence of this crystal is calculated to be 0.046.

[0099] Unless otherwise specified, the materials or processing techniques described in the above embodiments are all conventional commercially available products or conventional technologies in the art.

[0100] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate, characterized in that, The chemical formula of this crystalline material is (C2H5N4)(NO3), and the molecular weight is 147.

11. It includes two types: α-(C2H5N4)(NO3) and β-(C2H5N4)(NO3). The α-(C2H5N4)(NO3) crystallizes in the triclinic system, space group P1, with unit cell parameters of [missing information]. α = 110.44–114.63°, β = 93.04–97.71°, γ = 93.49–97.64°, Z = 2, cell volume is The β-(C2H5N4)(NO3) crystallizes in a monoclinic system with space group P21 and cell parameters of [missing information]. β = 88.32–92.14°, Z = 8, cell volume is V .

2. The method for preparing a polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate according to claim 1, characterized in that, When the crystal material is α-(C2H5N4)(NO3), the preparation method is as follows: Organic sources, inorganic sources and water are mixed in a certain stoichiometric ratio to form an initial mixed raw material. The obtained solution is placed in an open evaporating dish to volatilize and crystallize, and colorless and transparent crystalline form α is precipitated, which is α-(C2H5N4)(NO3) crystal material. The organic source is 3-amino-1,2,4-triazole; The inorganic source is nitric acid; The initial mixed raw materials have a molar ratio of organic source, inorganic source and water of 10:(10~60):(500~1250); a volatilization temperature of 10~45℃; and a volatilization time of not less than one week.

3. The method for preparing a polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate according to claim 2, characterized in that, When the crystal material is β-(C2H5N4)(NO3), the preparation method is as follows: Organic sources, inorganic sources and water are mixed in a certain stoichiometric ratio to form an initial mixed raw material. The obtained solution is placed in an open evaporating dish to volatilize and crystallize, and colorless and transparent crystal form β is precipitated, which is β-(C2H5N4)(NO3) crystal material. The organic source is 3-amino-1,2,4-triazole; The inorganic source is nitric acid; The initial mixed raw materials have a molar ratio of organic source, inorganic source and water of 10:(70~120):(500~1250); a volatilization temperature of 10~45℃; and a volatilization time of not less than one week.

4. The application of the polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate as described in claim 1 in laser frequency converters, optical parametric amplifiers, optical parametric oscillators, and photoelectric rectifiers.

5. The application of the polycrystalline nonlinear optical crystal material of 3-amino-1,2,4-triazole nitrate according to claim 4, characterized in that, The crystal material can be used in laser frequency converters to output 532nm under 1064nm laser irradiation.

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