Chiral zinc-based metal halide single crystal material as well as preparation method and application thereof

Abstract

The invention discloses a chiral zinc-based metal halide single crystal material as well as a preparation method and application thereof, and belongs to the field of nonlinear optical crystals. The single crystal material is a nonlinear optical crystal, belongs to an orthorhombic crystal system, has the characteristics of no lead, low toxicity, wide band gap and high stability, has second harmonic response, and shows a wide application prospect as a nonlinear optical crystal. According to the preparation method disclosed by the invention, crystal materials (3CLTPP) 2ZnBr4 and (5CLTPP) 2ZnBr4 crystallized in a chiral space group are constructed by using achiral element cyclopropyl triphenyl phosphonium cations or cyclopentyl triphenyl phosphonium cations, so that the traditional mode of constructing a chiral crystal material by using a chiral template agent is broken through; and a new guidance thought is provided for designing the chiral organic-inorganic hybrid metal halide crystal. The preparation method is simple to operate, mild in reaction and easy to popularize.

Description

Technical Field

[0001] The invention belongs to the technical field of nonlinear optical crystals, and in particular relates to a chiral zinc-based metal halide single crystal material and a preparation method and application thereof. Background Art

[0002] Organic-inorganic hybrid metal halides are a new type of material with rich chemical structures and compositions. They have received extensive attention in the field of nonlinear optical crystal materials. However, nonlinear optical crystal materials must meet strict symmetry requirements to be realized, so the preparation of such materials is a considerable challenge. The existing technology generally uses chiral organic templates to construct chiral organic-inorganic hybrid metal halide crystals. However, chiral organic templates are limited and expensive, which severely restricts the preparation of chiral organic-inorganic hybrid metal halides and their application in the field of nonlinear optics. Therefore, it is necessary to conduct in-depth research on the construction of chiral organic-inorganic hybrid metal halide single crystals with non-chiral templates, so as to open up new ideas for the design and synthesis of new organic-inorganic hybrid metal halide crystals. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a chiral zinc-based metal halide single crystal material having the advantages of lead-free, low toxicity, wide band gap, high stability and nonlinear optical properties, as well as a preparation method and application thereof.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A chiral zinc-based metal halide single crystal material, wherein the chemical formula of the single crystal material is (3CLTPP)2ZnBr4 or (5CLTPP)2ZnBr4, wherein 3CLTPP is a cyclopropyltriphenylphosphonium cation, and 5CLTPP is a cyclopentyltriphenylphosphonium cation, and the single crystal material is a nonlinear optical crystal belonging to the orthorhombic system; The chemical structure of (3CLTPP)2ZnBr4 is:

[0005] The chemical structure of (5CLTPP)2ZnBr4 is: .

[0006] The chiral zinc-based metal halide single crystal material is preferably a (3CLTPP)2ZnBr4 crystal structure in which the tetrahedral unit [ZnBr4] is separated by the cation 3CLTPP to form a zero-dimensional structure, and the space group is a chiral space group P 212121; The tetrahedral unit [ZnBr4] in the (5CLTPP)2ZnBr4 crystal structure is separated by the cation 5CLTPP to form a zero-dimensional structure, and the space group is a chiral space groupP 212121.

[0007] The chiral zinc-based metal halide single crystal material, preferably, (3CLTPP)2ZnBr4 has unit cell parameters of a=14.836(3) Å, b=16.240(3) Å, c=17.199(3) Å, α=β=γ=90 o ; The unit cell parameters of (5CLTPP)2ZnBr4 are a=15.087(3) Å, b=16.777(3) Å, c=17.377(3) Å, α=β=γ=90 o .

[0008] The above-mentioned chiral zinc-based metal halide single crystal material, preferably, the nonlinear optical crystal is a colorless and transparent crystal, the powder frequency doubling performance of the (3CLTPP)2ZnBr4 crystal is 0.18×KH2PO4, and the powder frequency doubling performance of the (5CLTPP)2ZnBr4 crystal is 0.10×KH2PO4.

[0009] As a general technical concept, the present invention also provides a method for preparing the above-mentioned chiral zinc-based metal halide single crystal material, comprising the following steps: (1) Dissolve the phenylphosphonium cation reagent and zinc bromide in methanol solution in an open container and stir thoroughly at room temperature to form a clear and transparent precursor solution; (2) Place the open container containing the precursor solution in a covered container containing ether at room temperature, cover it with a lid and seal it, and let it stand until the ether diffuses into the precursor solution to form colorless block crystals; (3) washing the colorless block crystals with ether and drying under reduced pressure to obtain a chiral zinc-based metal halide single crystal material; When the phenylphosphonium cation reagent is cyclopropyltriphenylphosphonium bromide, the chemical formula of the chiral zinc-based metal halide single crystal material is (3CLTPP)2ZnBr4; When the phenylphosphonium cation reagent is cyclopentyltriphenylphosphonium bromide, the chemical formula of the chiral zinc-based metal halide single crystal material is (5CLTPP)2ZnBr4.

[0010] In the above-mentioned method for preparing the chiral zinc-based metal halide single crystal material, preferably, in step (1) and step (2), the molar mass volume ratio of the phenylphosphonium cation reagent, zinc bromide, methanol and diethyl ether is 0.2 mmol to 0.3 mmol: 0.1 mmol to 0.15 mmol: 2 mL to 3 mL: 20 mL to 25 mL.

[0011] In the above-mentioned method for preparing the chiral zinc-based metal halide single crystal material, preferably, in step (1), the stirring speed is 200 r / min to 300 r / min, and the stirring time is 5 min to 10 min.

[0012] In the above method for preparing the chiral zinc-based metal halide single crystal material, preferably, in step (2), the diffusion time is 36 h to 48 h.

[0013] In the above-mentioned method for preparing the chiral zinc-based metal halide single crystal material, preferably, in step (3), the reduced pressure drying is specifically: drying for at least 10 min at a temperature of 50°C to 60°C under a vacuum pressure of 100 Pa to 120 Pa.

[0014] As a general technical concept, the present invention also provides an application of the chiral zinc-based metal halide single crystal material or the chiral zinc-based metal halide single crystal material prepared by the above preparation method in the field of nonlinear optics.

[0015] Compared with the prior art, the advantages of the present invention are: (1) The chiral zinc-based metal halide single crystal material of the present invention has a chemical formula of (3CLTPP)2ZnBr4 or (5CLTPP)2ZnBr4, wherein 3CLTPP is a cyclopropyltriphenylphosphonium cation and 5CLTPP is a cyclopentyltriphenylphosphonium cation. The present invention adopts specific non-chiral elementary cyclopropyltriphenylphosphonium cation and cyclopentyltriphenylphosphonium cation to obtain a chiral zinc-based metal halide single crystal material, i.e., a chiral zinc-based organic-inorganic hybrid metal halide crystal material. The single crystal material is a nonlinear optical crystal belonging to the orthorhombic crystal system and has the advantages of lead-free, low toxicity, wide band gap and high stability. It also has a second harmonic response (0.18×KH2PO4 and 0.10×KH2PO4) and has good nonlinear optical properties.

[0016] (2) The preparation method of the chiral zinc-based metal halide single crystal material of the present invention breaks the inherent limitation of using chiral templates to construct chiral organic-inorganic hybrid metal halide single crystal materials. It cleverly uses non-chiral primitives cyclopropyltriphenylphosphonium bromide, cyclopentyltriphenylphosphonium bromide and zinc bromide as raw materials, methanol as a good solvent, and ether as an anti-solvent to synthesize chiral zinc-based organic-inorganic hybrid metal halide crystal compounds (3CLTPP)2ZnBr4 or (5CLTPP)2ZnBr4 by the anti-solvent method at room temperature. The preparation method is simple to operate, mild in reaction, and easy to scale up for production.

[0017] (3) The chiral zinc-based metal halide single crystal material of the present invention has the advantages of being lead-free, low-toxic, having a wide bandgap and high stability, and also has a second harmonic response, and has good application prospects in nonlinear optics. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagrams of the crystal structures of the chiral zinc-based metal halide single crystal materials of Examples 1 and 2 of the present invention, wherein (a) is a schematic diagram of the crystal structure of (3CLTPP)2ZnBr4, and (b) is a schematic diagram of the crystal structure of (5CLTPP)2ZnBr4.

[0019] Figure 2 These are XRD diagrams of the chiral zinc-based metal halide single crystal materials of Examples 1 and 2 of the present invention, wherein (a) is the XRD diagram of the (3CLTPP)2ZnBr4 crystal, and (b) is the XRD diagram of the (5CLTPP)2ZnBr4 crystal.

[0020] Figure 3 The ultraviolet-visible absorption spectra of the chiral zinc-based metal halide single crystal materials of Examples 1 and 2 of the present invention are shown.

[0021] Figure 4 This is a comparison chart of the second harmonic signal intensities of the chiral zinc-based metal halide single crystal materials and KH2PO4 in Examples 1 and 2 of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following examples and comparative examples are all commercially available, and the room temperature referred to is 25°C to 30°C.

[0023] Example 1 A chiral zinc-based metal halide single crystal material, the chemical formula of the single crystal material is (3CLTPP)2ZnBr4, wherein 3CLTPP is a cyclopropyltriphenylphosphonium cation, and the chemical structure of (3CLTPP)2ZnBr4 is:

[0024] The single crystal material of this embodiment is a nonlinear optical crystal, which is colorless and transparent, belongs to the orthorhombic system, and the space group is a chiral space group P 212121, the unit cell parameters are a=14.836(3) Å, b=16.240(3) Å, c=17.199(3) Å, α=β=γ=90 o ; Its powder frequency doubling performance is 0.18×KH2PO4.

[0025] A method for preparing the chiral zinc-based metal halide single crystal material of the present embodiment comprises the following steps: (1) In a 5 mL open glass bottle, dissolve 76.65 mg (0.2 mmol) of cyclopropyltriphenylphosphonium bromide and 22.52 mg (0.1 mmol) of zinc bromide in 2 mL of methanol solution and stir thoroughly at room temperature until a clear and transparent precursor solution is formed; (2) Place the glass bottle containing the precursor solution in a 50 mL covered glass bottle containing 20 mL of ether at room temperature, cover the bottle cap, and let it stand, waiting for the ether to diffuse into the precursor solution for 36 hours to form colorless block crystals; (3) Wash the colorless block crystals with ether and dry them under reduced pressure to obtain a chiral zinc-based metal halide single crystal material with the chemical formula (3CLTPP)2ZnBr4.

[0026] In step (1), the stirring speed is 200 r / min and the stirring time is 5 min.

[0027] In step (3), the reduced pressure drying is specifically: drying at a temperature of 50° C. for 10 min under a vacuum pressure of 100 Pa.

[0028] Example 2 A chiral zinc-based metal halide single crystal material, the chemical formula of the single crystal material is (5CLTPP)2ZnBr4, wherein 5CLTPP is a cyclopentyltriphenylphosphonium cation, and the chemical structure of (5CLTPP)2ZnBr4 is:

[0029] The single crystal material of this embodiment is a nonlinear optical crystal, which is colorless and transparent, belongs to the orthorhombic system, and the space group is a chiral space group P 212121, unit cell parameters are a=15.087(3) Å, b=16.777(3) Å, c=17.377(3) Å, α=β=γ=90 o ; Its powder frequency doubling performance is 0.10×KH2PO4.

[0030] A method for preparing the chiral zinc-based metal halide single crystal material of the present embodiment comprises the following steps: (1) In a 5 mL open glass bottle, dissolve 82.26 mg (0.2 mmol) of cyclopentyltriphenylphosphonium bromide and 22.52 mg (0.1 mmol) of zinc bromide in 2 mL of methanol solution and stir thoroughly at room temperature until a clear and transparent precursor solution is formed; (2) Place the glass bottle containing the precursor solution in a 50 mL covered glass bottle containing 20 mL of ether at room temperature, cover the bottle cap, and let it stand, waiting for the ether to diffuse into the precursor solution for 36 hours to form colorless block crystals; (3) Wash the colorless block crystals with ether and dry them under reduced pressure to obtain a chiral zinc-based metal halide single crystal material with the chemical formula (5CLTPP)2ZnBr4.

[0031] In step (1), the stirring speed is 200 r / min and the stirring time is 5 min.

[0032] In step (3), the reduced pressure drying is specifically: drying at a temperature of 50° C. for 10 min under a vacuum pressure of 100 Pa.

[0033] Performance Testing (1) SCXRD test: The single crystal diffraction data were measured at 298 K using a Bruker D8 Venture single crystal diffractometer (Mo Ka), and the data were reduced using the Bruker APEX3 program. Subsequently, the Olex2 program based on the SHELXTL software package was used for preliminary structural analysis, and the coordinates of all non-hydrogen atoms were determined by the difference Fourier method. All non-hydrogen atoms were then anisotropically refined using the least squares method based on F2, and the positions of hydrogen atoms were obtained by theoretical hydrogenation.

[0034] SCXRD tests on (3CLTPP)2ZnBr4 and (5CLTPP)2ZnBr4 crystal materials show that both belong to the orthorhombic system and have chiral space groups. P 212121, (3CLTPP)2ZnBr4 unit cell parameters are a=14.836(3) Å, b=16.240(3) Å, c=17.199(3) Å, α=β=γ=90 o ;(5CLTPP)2ZnBr4 unit cell parameters are a=15.087(3) Å, b=16.777(3)Å, c=17.377(3) Å, α=β=γ=90 o The obtained crystal structure is shown in Figure 1 As shown, Figure 1 (a) is a schematic diagram of the crystal structure of (3CLTPP)2ZnBr4. Figure 1 (b) is a schematic diagram of the crystal structure of (5CLTPP)2ZnBr4. Figure 1 (a) shows that the tetrahedral unit [ZnBr4] in the (3CLTPP)2ZnBr4 crystal structure is separated by the cation 3CLTPP to form a zero-dimensional structure; Figure 1As can be seen in (b), the tetrahedral unit [ZnBr4] in the (5CLTPP)2ZnBr4 crystal structure is separated by the cation 5CLTPP to form a zero-dimensional structure.

[0035] (2) RXRD test: The powder diffraction data were measured at 298 K using a SmartLab X-ray powder diffractometer (Cu Ka), and the powder diffraction simulation pattern was simulated based on the single crystal structure using Mercury software.

[0036] The powder samples of (3CLTPP)2ZnBr4 and (5CLTPP)2ZnBr4 were ball-milled and subjected to PXRD test. The results are as follows: Figure 2 As shown, Figure 2 (a) is the XRD pattern of (3CLTPP)2ZnBr4 crystal. Figure 2 (b) is the XRD pattern of (5CLTPP)2ZnBr4 crystal. Figure 2 As shown in (a), the PXRD pattern of (3CLTPP)2ZnBr4 crystal measured is consistent with the simulated SCXRD pattern. Figure 2 As can be seen in (b), the PXRD pattern of (5CLTPP)2ZnBr4 crystal measured is consistent with the simulated SCXRD pattern, which confirms that both crystalline materials are pure phases.

[0037] (3) UV-visible absorption test: The UV-visible absorption spectrum data were measured using a UV-3600i Plus UV-visible near-infrared spectrophotometer.

[0038] The UV-visible absorption test of (3CLTPP)2ZnBr4 and (5CLTPP)2ZnBr4 crystal materials was carried out. The results are as follows: Figure 3 As described above, it can be calculated that the band gap of the crystalline material (3CLTPP)2ZnBr4 is 4.2 eV, and the band gap of (5CLTPP)2ZnBr4 is 4.26 eV.

[0039] (4) Powder frequency doubling test: The powder SHG measurements were performed on a modified Kurtz-NLO system using a Nd:YAG laser (1064 nm) with an input pulse of 350 mV.

[0040] The powder frequency doubling test of (3CLTPP)2ZnBr4 and (5CLTPP)2ZnBr4 crystal materials was carried out. The crystal materials were sieved to a particle size of 30 um to 50 um and then the frequency doubling test was carried out. The results are as follows: Figure 4As shown, all crystal materials have a frequency doubling effect. The frequency doubling performance of (3CLTPP)2ZnBr4 is 0.18×KH2PO4, and the frequency doubling performance of (5CLTPP)2ZnBr4 is 0.10×KH2PO4.

[0041] In summary, the preparation method of the present invention breaks the limitation of the conventional chiral zinc-based organic-inorganic hybrid metal halide single crystal material constructed with a chiral template, and ingeniously constructs a chiral nonlinear optical crystal with a non-chiral unit. The prepared crystal has the advantages of lead-free, low toxicity, wide band gap and high stability (compared with the existing conventional metal halide crystals that decompose in one or two days at room temperature, the single crystal material of the present invention can maintain the crystal form for a long time at room temperature), and its powder frequency doubling performance is 0.18×KH2PO4 ((3CLTPP)2ZnBr4) and 0.10×KH2PO4 ((5CLTPP)2ZnBr4), respectively, showing good application potential as a nonlinear optical crystal.

[0042] Comparative Example 1 A zinc-based metal halide single crystal material, the chemical formula of which is (6CLTPP)2ZnBr4, wherein 6CLTPP is a cyclohexyltriphenylphosphonium cation.

[0043] A method for preparing the zinc-based metal halide single crystal material of the comparative example comprises the following steps: (1) In a 5 mL open glass bottle, dissolve 85.07 mg (0.2 mmol) of cyclohexyltriphenylphosphonium bromide (6CLTPPBr) and 22.52 mg (0.1 mmol) of zinc bromide in 2 mL of methanol solution and stir thoroughly at room temperature until a clear and transparent precursor solution is formed; (2) Place the glass bottle containing the precursor solution in a 50 mL covered glass bottle containing 20 mL of ether at room temperature, cover the bottle cap, and let it stand, waiting for the ether to diffuse into the precursor solution for 36 hours to form colorless block crystals; (3) Wash the colorless block crystals with ether and dry them under reduced pressure to obtain a zinc-based metal halide single crystal material with a chemical formula of (6CLTPP)2ZnBr4.

[0044] In step (1), the stirring speed is 200 r / min and the stirring time is 5 min.

[0045] In step (3), the reduced pressure drying is specifically: drying at a temperature of 50° C. for 10 min under a vacuum pressure of 100 Pa.

[0046] The performance of the crystalline material obtained in this comparative example was tested according to the test methods in Examples 1 and 2, and the space group of (6CLTPP)2ZnBr4 was obtained to beC 2 / c , the unit cell parameters are a=23.497(3) Å, b=13.5622(14) Å, c=19.439(2) Å, β=125.262(3) o .

[0047] The crystal belongs to a centrosymmetric monoclinic space group and has a centrosymmetric structure, so it has no nonlinear optical properties.

[0048] Comparative Example 2 A zinc-based metal halide single crystal material has a chemical formula of (AETPP)2ZnBr4, wherein AETPP is an allyltriphenylphosphonium cation.

[0049] A method for preparing the zinc-based metal halide single crystal material of the comparative example comprises the following steps: (1) In a 5 mL open glass bottle, dissolve 76.65 mg (0.2 mmol) of allyltriphenylphosphonium bromide (AETPPBr) and 22.52 mg (0.1 mmol) of zinc bromide in 2 mL of methanol solution and stir thoroughly at room temperature until a clear and transparent precursor solution is formed; (2) Place the glass bottle containing the precursor solution in a 50 mL covered glass bottle containing 20 mL of ether at room temperature, cover the bottle cap, and let it stand, waiting for the ether to diffuse into the precursor solution for 36 hours to form colorless block crystals; (3) Wash the colorless block crystals with ether and dry them under reduced pressure to obtain a zinc-based metal halide single crystal material with a chemical formula of (AETPP)2ZnBr4.

[0050] In step (1), the stirring speed is 200 r / min and the stirring time is 5 min.

[0051] In step (3), the reduced pressure drying is specifically: drying at a temperature of 50° C. for 10 min under a vacuum pressure of 100 Pa.

[0052] The performance of the crystalline material obtained in this comparative example was tested according to the test methods in Examples 1 and 2, and the space group of (AETPP)2ZnBr4 was obtained to be C 2 / c , the unit cell parameters are a=20.1139(10) Å, b=12.8172(7) Å, c=18.6643(9) Å, β=119.872(2) o .

[0053] The crystal belongs to a centrosymmetric monoclinic space group and has a centrosymmetric structure, so it has no nonlinear optical properties.

[0054] Comparative Example 3 A zinc-based metal halide single crystal material has a chemical formula of (BETPP)2ZnBr4, wherein BETPP is an isopropyltriphenylphosphonium cation.

[0055] A method for preparing the zinc-based metal halide single crystal material of the comparative example comprises the following steps: (1) In a 5 mL open glass bottle, dissolve 86.46 mg (0.2 mmol) of isopropyltriphenylphosphonium iodide (BETPPI) and 22.52 mg (0.1 mmol) of zinc bromide in 2 mL of methanol solution and stir thoroughly at room temperature until a clear and transparent precursor solution is formed; (2) Place the glass bottle containing the precursor solution in a 50 mL covered glass bottle containing 20 mL of ether at room temperature, cover the bottle cap, and let it stand, waiting for the ether to diffuse into the precursor solution for 36 hours to form colorless block crystals; (3) Wash the colorless block crystals with ether and dry them under reduced pressure to obtain a zinc-based metal halide single crystal material with a chemical formula of (BETPP)2ZnBr4.

[0056] In step (1), the stirring speed is 200 r / min and the stirring time is 5 min.

[0057] In step (3), the reduced pressure drying is specifically: drying at a temperature of 50° C. for 10 min under a vacuum pressure of 100 Pa.

[0058] The performance of the crystalline material obtained in this comparative example was tested according to the test methods in Examples 1 and 2, and the space group of (BETPP)2ZnBr4 was obtained to be P twenty one / c , the unit cell parameters are a=19.791(3) Å, b=12.487(3) Å, c=19.428(4)Å, β=98.817(4) o .

[0059] The crystal belongs to a centrosymmetric monoclinic space group and has a centrosymmetric structure, so it has no nonlinear optical properties.

[0060] Comparative Example 4 A zinc-based metal halide single crystal material has a chemical formula of (DOTPP)2ZnBr4, wherein DOTPP is triphenylphosphonium acetal glycol cation.

[0061] A method for preparing the zinc-based metal halide single crystal material of the comparative example comprises the following steps: (1) In a 5 mL open glass bottle, dissolve 85.86 mg (0.2 mmol) of acetaldehyde glycol triphenylphosphonium bromide (DOTPPBr) and 22.52 mg (0.1 mmol) of zinc bromide in 2 mL of methanol solution and stir thoroughly at room temperature until a clear and transparent precursor solution is formed; (2) Place the glass bottle containing the precursor solution in a 50 mL covered glass bottle containing 20 mL of ether at room temperature, cover the bottle cap, and let it stand, waiting for the ether to diffuse into the precursor solution for 36 hours to form colorless block crystals; (3) Wash the colorless block crystals with ether and dry them under reduced pressure to obtain a zinc-based metal halide single crystal with the chemical formula (DOTPP)2ZnBr4.

[0062] In step (1), the stirring speed is 200 r / min and the stirring time is 5 min.

[0063] In step (3), the reduced pressure drying is specifically: drying at a temperature of 50° C. for 10 min under a vacuum pressure of 100 Pa.

[0064] The performance of the crystalline material obtained in this comparative example was tested according to the test methods in Examples 1 and 2, and the space group of (DOTPP)2ZnBr4 was obtained to be P twenty one / n , the unit cell parameters are a=12.081(4) Å, b=18.119(5) Å, c=20.151(6)Å, β=91.242(10) o .

[0065] The crystal belongs to a centrosymmetric monoclinic space group and has a centrosymmetric structure, so it has no nonlinear optical properties.

[0066] In summary, although the phenylphosphonium cations used in Examples 1 to 2 and Comparative Examples 1 to 4 are all achiral units and the experimental conditions are the same, the specific phenylphosphonium cations selected in Comparative Examples 1 to 4 are different from those in Examples 1 and 2, and the chiral zinc-based metal halide single crystal material of the present invention cannot be prepared.

[0067] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the spirit and technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A chiral zinc-based metal halide single crystal material, characterized in that: The chemical formula of the single crystal material is (3CLTPP)2ZnBr4 or (5CLTPP)2ZnBr4, wherein 3CLTPP is a cyclopropyltriphenylphosphonium cation, and 5CLTPP is a cyclopentyltriphenylphosphonium cation. The single crystal material is a nonlinear optical crystal and belongs to the orthorhombic system. The chemical structure of (3CLTPP)2ZnBr4 is: The chemical structure of (5CLTPP)2ZnBr4 is: 。 2. The chiral zinc-based metal halide single crystal material according to claim 1, characterized in that: The tetrahedral unit [ZnBr4] in the (3CLTPP)2ZnBr4 crystal structure is separated by the cation 3CLTPP to form a zero-dimensional structure with a chiral space group. P 212121; The tetrahedral unit [ZnBr4] in the (5CLTPP)2ZnBr4 crystal structure is separated by the cation 5CLTPP to form a zero-dimensional structure, and the space group is a chiral space group P 212121.

3. The chiral zinc-based metal halide single crystal material according to claim 2, characterized in that: The unit cell parameters of (3CLTPP)2ZnBr4 are a=14.836(3) Å, b=16.240(3) Å, c=17.199(3) Å, α=β=γ=90 o ; The unit cell parameters of (5CLTPP)2ZnBr4 are a=15.087(3) Å, b=16.777(3) Å, c=17.377(3) Å, α=β=γ=90 o .

4. The chiral zinc-based metal halide single crystal material according to any one of claims 1 to 3, characterized in that: The nonlinear optical crystal is a colorless and transparent crystal. The powder frequency doubling performance of the (3CLTPP)2ZnBr4 crystal is 0.18×KH2PO4, and the powder frequency doubling performance of the (5CLTPP)2ZnBr4 crystal is 0.10×KH2PO4.

5. A method for preparing a chiral zinc-based metal halide single crystal material according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Dissolve the phenylphosphonium cation reagent and zinc bromide in methanol solution in an open container and stir thoroughly at room temperature to form a clear and transparent precursor solution; (2) Place the open container containing the precursor solution in a covered container containing ether at room temperature, cover it with a lid and seal it, and let it stand until the ether diffuses into the precursor solution to form colorless block crystals; (3) washing the colorless block crystals with ether and drying under reduced pressure to obtain a chiral zinc-based metal halide single crystal material; When the phenylphosphonium cation reagent is cyclopropyltriphenylphosphonium bromide, the chemical formula of the chiral zinc-based metal halide single crystal material is (3CLTPP)2ZnBr4; When the phenylphosphonium cation reagent is cyclopentyltriphenylphosphonium bromide, the chemical formula of the chiral zinc-based metal halide single crystal material is (5CLTPP)2ZnBr4.

6. The method for preparing a chiral zinc-based metal halide single crystal material according to claim 5, characterized in that: In step (1) and step (2), the molar mass volume ratio of the phenylphosphonium cation reagent, zinc bromide, methanol and diethyl ether is 0.2 mmol to 0.3 mmol: 0.1 mmol to 0.15 mmol: 2 mL to 3 mL: 20 mL to 25 mL.

7. The method for preparing a chiral zinc-based metal halide single crystal material according to claim 5, characterized in that: In step (1), the stirring speed is 200 r / min to 300 r / min, and the stirring time is 5 min to 10 min.

8. The method for preparing a chiral zinc-based metal halide single crystal material according to claim 5, characterized in that: In step (2), the diffusion time is 36 h to 48 h.

9. The method for preparing a chiral zinc-based metal halide single crystal material according to any one of claims 5 to 8, characterized in that: In step (3), the reduced pressure drying specifically comprises: drying for at least 10 min at a temperature of 50° C. to 60° C. under a vacuum pressure of 100 Pa to 120 Pa.

10. Use of the chiral zinc-based metal halide single crystal material according to any one of claims 1 to 4 or the chiral zinc-based metal halide single crystal material prepared by the preparation method according to any one of claims 5 to 9 in the field of nonlinear optics.

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