Nonlinear optical crystal and preparation method and application thereof

Abstract

The invention relates to the technical field of nonlinear optics, and discloses a nonlinear optical crystal as well as a preparation method and application thereof, and the chemical formula of the nonlinear optical crystal is (S-C9H14N) 4Bi2Cl10. The non-linear optical crystal is a lead-free organic-inorganic perovskite crystal, does not contain toxic lead, has a transmission range of 0.33-3.0 [mu] m, has powder frequency doubling performance equivalent to that of 0.029 * AgGaS2, can be applied to the field of non-linear optics, and enriches the research content of non-linear optical materials.

Description

Technical Field

[0001] The present application relates to the technical field of nonlinear optics, and mainly to a nonlinear optical crystal and a preparation method and application thereof. Background Art

[0002] Since the advent of lasers in the 1960s, nonlinear optics has played an increasingly important role in the field of optics. In the field of nonlinear optics, the research focus is mainly on various nonlinear optical phenomena generated between laser beams and materials. By utilizing the second-order nonlinear optical effect (frequency doubling effect) of the material, the output frequency of the fundamental frequency incident light can be changed to achieve functions such as laser frequency conversion, laser wavelength extension, and laser phase modulation, which plays a vital role in laser manufacturing, optical communications, treatment, and military applications. Currently, the most widely used nonlinear optical crystals are mainly inorganic materials, but their inherent disadvantages (such as incompatibility with flexible substrates and processing difficulties) greatly hinder their potential applications in flexible and integrated nonlinear optical devices. Therefore, it is imperative to develop new nonlinear optical materials to promote the development of the field of nonlinear optics.

[0003] Organic-inorganic perovskites, with their rich chemical structures and optoelectronic properties, have emerged as a promising material for optoelectronic applications. In particular, the destruction of lattice inversion symmetry caused by chiral cations has opened up new avenues for chiral organic-inorganic perovskites in the field of nonlinear optics. Compared with three-dimensional materials, low-dimensional perovskite materials exhibit more obvious nonlinear optical responses due to factors such as light-matter interactions, various exciton effects, structural diversity, and large lattice distortion. At the same time, the large band gaps of these low-dimensional perovskite materials make them transparent over a wider spectral range, providing a wider wavelength window for second-order nonlinear optical applications. However, most low-dimensional chiral perovskite materials contain toxic Pb 2+ , which seriously hinders the commercial application of their nonlinear optical devices. 3+ With Pb 2+ Similar ionic radius and electronegativity, but with toxic Pb 2+ Less toxic than Pb 2+ An ideal electronic substitute for 3+ The introduction of can also promote the formation of low-dimensional perovskite structure and further improve stability. Therefore, non-toxic bismuth-based low-dimensional organic-inorganic perovskites will become a new and important exploration field for perovskite applications, which will accelerate the development of integrated nonlinear optical devices. It is imperative to develop new bismuth-based low-dimensional organic-inorganic perovskites to promote the development of nonlinear optics.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a nonlinear optical crystal and a preparation method and application thereof, aiming to provide a new bismuth-based low-dimensional organic-inorganic perovskite, the nonlinear optical crystal is a lead-free organic-inorganic perovskite crystal ( S -C 9 H 14 N) 4 Bi 2 Cl 10 , showing excellent nonlinear optical properties, opening up a new field for the research of nonlinear optical materials.

[0006] The technical solution of this application is as follows: A nonlinear optical crystal, wherein the chemical formula of the nonlinear optical crystal is ( S -C 9 H 14 N) 4 Bi 2 Cl 10 .

[0007] The nonlinear optical crystal, wherein the nonlinear optical crystal belongs to the monoclinic system and the space group is P2 1 , the unit cell parameters are a=11.8065 Å, b=25.4721 Å, c=32.3996 Å, α=γ=90°, β=91.332°, V=9741.1 Å 3 .

[0008] The nonlinear optical crystal is a translucent white crystal with a transmission range of 0.33-3.0 μm and a frequency doubling performance of 0.029×AgGaS 2 .

[0009] A method for preparing the nonlinear optical crystal as described above, comprising the following steps: Bi 2 O 3 and( S )-(-)-b-methylphenethylamine as raw material, at room temperature S )-(-)-b-methylphenethylamine and the Bi 2 O 3 The two are dissolved in a hydrochloric acid solution respectively, and after being dissolved, the two are mixed, heated and stirred to volatilize part of the solvent, and crystals are precipitated to obtain the nonlinear optical crystal.

[0010] The method for preparing nonlinear optical crystals, wherein the heating and stirring to volatilize part of the solvent and precipitate the crystals comprises the following steps: Heat and stir to volatilize part of the solvent, wait for the mixed solution to cool to room temperature in a supersaturated state, and stand to crystallize; The process of standing crystallization comprises the following steps: After standing for 120-240 minutes, crystal particles appear at the bottom of the container. Continue to stand to allow the crystals to grow until no more precipitation occurs. After the step of standing and crystallizing, the method further comprises the following steps: The solution was filtered off, and the precipitated crystals were washed clean with pure chlorobenzene and dried at room temperature.

[0011] The method for preparing nonlinear optical crystals, wherein the heating and stirring to volatilize part of the solvent and precipitate the crystals comprises the following steps: The solvent is partially volatilized by heating and stirring. After the mixed solution is cooled to room temperature, the mixed solution is added dropwise into pure chlorobenzene with magnetic stirring. After the addition is completed, the substance precipitated in the pure chlorobenzene is filtered out, rinsed with pure chlorobenzene, and dried at room temperature.

[0012] The method for preparing the nonlinear optical crystal, wherein the ( S )-(-)-b-methylphenethylamine and the Bi 2 O 3 The process of dissolving in hydrochloric acid solution respectively specifically comprises the following steps: At room temperature, the S )-(-)-b-methylphenethylamine is dissolved in the hydrochloric acid solution, and stirred at 100-200° C. for 30-60 min to fully dissolve it; At room temperature, the Bi 2 O 3 Dissolve in the hydrochloric acid solution, stir at 100-200°C for 30-60 minutes to fully dissolve; The mass concentration range of the hydrochloric acid solution is 36%-38%; The Bi 2 O 3 The molar ratio between the (S)-(-)-b-methylphenylethylamine is 1:2-4; For 1 mmol of Bi 2 O 3 Correspondingly, 10-20 ml of the hydrochloric acid solution is used, for every 4 mmol of the ( S )-(-)-b-methylphenethylamine correspondingly uses 10-20 ml of the hydrochloric acid solution.

[0013] The method for preparing the nonlinear optical crystal comprises the following steps: heating and stirring to volatilize part of the solvent, the heating temperature is 120-200° C., and the stirring time is 1 h-2 h.

[0014] The method for preparing the nonlinear optical crystal, wherein the Bi 2 O 3 The molar ratio between the (S)-(-)-b-methylphenethylamine is 1:4; The heating and stirring volatilizes part of the solvent, and the heating temperature is 150°C.

[0015] An application of the nonlinear optical crystal as described above, wherein the nonlinear optical crystal is used to prepare a nonlinear optical device.

[0016] Beneficial effect: The nonlinear optical crystal of the present application is an organic-inorganic perovskite crystal ( S -C 9 H 14 N) 4 Bi 2 Cl 10 , does not contain toxic lead, has a transmission range of 0.33-3.0 μm, and its powder frequency doubling performance is comparable to 0.029×AgGaS 2 Therefore, the nonlinear optical crystal can be applied to the field of nonlinear optics and enrich the research content of nonlinear optical materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The lead-free organic-inorganic perovskite crystal prepared in Example 1 of the present application ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Schematic diagram of .

[0018] Figure 2 The lead-free organic-inorganic perovskite crystal prepared in Example 1 of the present application ( S -C 9 H 14 N) 4 Bi 2 Cl 10 SEM image of .

[0019] Figure 3 The lead-free organic-inorganic perovskite crystal prepared in Example 1 of the present application ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Schematic diagram of the structure.

[0020] Figure 4 The lead-free organic-inorganic perovskite crystal prepared in Example 1 of the present application ( S -C9 H 14 N) 4 Bi 2 Cl 10 XRD pattern of .

[0021] Figure 5 The lead-free organic-inorganic perovskite crystal prepared in Example 1 of the present application ( S -C 9 H 14 N) 4 Bi 2 Cl 10 UV-NIR transmission spectrum.

[0022] Figure 6 The lead-free organic-inorganic perovskite crystal prepared in Example 1 of the present application ( S -C 9 H 14 N) 4 Bi 2 Cl 10 With AgGaS 2 Comparison of the second frequency intensity.

[0023] Figure 7 The lead-free organic-inorganic perovskite crystal prepared in Example 2 of the present application ( S -C 9 H 14 N) 4 Bi 2 Cl 10 XRD pattern of . DETAILED DESCRIPTION

[0024] The present application provides a nonlinear optical crystal and a preparation method and application thereof. To make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] The present application provides a nonlinear optical crystal by S )-(-)-b-Methylphenethylamine was inserted into the lead-free inorganic framework, achieving chirality transfer from the organic part to the inorganic part and obtaining a non-centrosymmetric chiral crystal structure.

[0026] Specifically, the nonlinear optical crystal of the present application is a lead-free organic-inorganic perovskite crystal, and its chemical formula is ( S -C 9 H 14 N) 4 Bi 2 Cl 10, belongs to the monoclinic system, and the space group is P2 1 , the unit cell parameters are: a=11.8065 Å, b=25.4721 Å, c=32.3996 Å, α=γ=90°, β=91.332°, V=9741.1 Å 3 .

[0027] ( S -C 9 H 14 N) 4 Bi 2 Cl 10 The crystal is translucent white, does not contain toxic lead, has a transmittance range of 0.33-3.0μm, and its powder frequency doubling performance is 0.029×AgGaS 2 , ( S -C 9 H 14 N) 4 Bi 2 Cl 10 The crystal exhibits excellent nonlinear optical properties and can be applied in the field of nonlinear optics, enriching the research content of nonlinear optical materials.

[0028] The nonlinear optical crystal of the present application can be prepared by solution evaporation or anti-solvent precipitation. The material prepared by solution evaporation has slightly better crystallinity and can obtain small grains. The material prepared by anti-solvent precipitation has slightly worse crystallinity and a powdery morphology. Different crystallinities and different morphologies are suitable for different use scenarios, and the preparation method can be selected according to needs.

[0029] Furthermore, the present application also provides a method for preparing the above-mentioned nonlinear optical crystal, which can be grown by solution evaporation method at room temperature. The preparation method is simple and easy to operate.

[0030] Specifically, the method for preparing the nonlinear optical crystal of the present application comprises the following steps: Bi 2 O 3 and( S )-(-)-b-methylphenylethylamine as raw material, at room temperature ( S )-(-)-b-methylphenethylamine and Bi 2 O 3 Dissolve them separately in hydrochloric acid solution, mix them after dissolution, heat and stir to volatilize part of the solvent, wait for the mixed solution to cool to room temperature in a supersaturated state, stand and crystallize, and the obtained translucent white crystals are ( S -C 9 H 14 N) 4 Bi 2 Cl 10Crystal.

[0031] Furthermore, the present application also provides a method for preparing the above-mentioned nonlinear optical crystal, which can be prepared by an anti-solvent precipitation method. The preparation method is simple and easy to operate.

[0032] Specifically, the method for preparing the nonlinear optical crystal of the present application comprises the following steps: Bi 2 O 3 and( S )-(-)-b-methylphenylethylamine as raw material, at room temperature ( S )-(-)-b-methylphenethylamine and Bi 2 O 3 Dissolve them in hydrochloric acid solution respectively, mix them after dissolution, heat and stir to volatilize part of the solvent, wait for the mixed solution to cool to room temperature, add the mixed solution drop by drop into pure chlorobenzene with magnetic stirring, after the addition is complete, filter to obtain the substance precipitated in pure chlorobenzene, rinse with pure chlorobenzene, and dry at room temperature to obtain ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Crystal.

[0033] In the above two preparation methods, the mass concentration range of the hydrochloric acid solution can be 36%-38%. Using this concentration range is conducive to the dissolution of the raw materials and is safer to operate.

[0034] In the above two preparation methods, the hydrochloric acid solution not only acts as a solvent, but also participates in the structural synthesis of the material. 2 O 3 10-20 ml of hydrochloric acid solution can be used for each 4 mmol ( S )-(-)-b-methylphenylethylamine can be used with 10-20 ml of hydrochloric acid solution. This ratio range is helpful for dissolving the raw materials on the one hand, and adding an appropriate amount of hydrochloric acid solution can reduce the time of subsequent volatilization on the other hand. In addition, in the preparation process of the solution evaporation method, the supersaturated state must be maintained when cooling and precipitating crystals at the end, so heating and stirring are required to volatilize excess solvent. If the solution is small and the temperature is high, it is easy to boil, and if the solution is too much, the volatilization time is long.

[0035] Specifically, in the process of heating and stirring to volatilize part of the solvent, the heating temperature can be 120-200 ° C, and the stirring time can be 1h-2h. Heating helps the two to dissolve and mix, and can volatilize excess solvent at the same time. If the temperature is too low, the dissolution time is long and the volatilization time is long. If the temperature is too high, the dissolution process is prone to boiling. Preferably, the heating temperature is preferably selected to be 150 ° C. In the preparation process of the solution evaporation method, the stirring time is mainly adjusted according to the amount of the solvent, and a certain stirring time is required to volatilize the solvent so that the solution reaches a supersaturated state after cooling, which is conducive to subsequent crystal precipitation. In the preparation process of the anti-solvent precipitation method, the stirring time is mainly adjusted according to the amount of the solvent, and the solvent is volatilized by a shorter stirring time so that the solution is in a moderate concentration state, which is conducive to the mixed solution when chlorobenzene is dripped into more crystals and reduces the synthesis time.

[0036] Furthermore, 2 O 3 The molar ratio between Bi and (S)-(-)-b-methylphenylethylamine can be 1:2-4, preferably 1:4. 2 O 3 and( S The ratio of )-(-)-b-methylphenylethylamine is 1:4. Theoretically, if the ratio is wrong, it will be difficult to obtain the target compound. However, in fact, during the experiment, Bi 2 O 3 and( S The target compound can be prepared when the molar ratio of )-(-)-b-methylphenethylamine is 1:2-4.

[0037] Furthermore, at room temperature ( S )-(-)-b-methylphenethylamine and Bi 2 O 3 The process of dissolving in hydrochloric acid solution respectively specifically comprises the following steps: (1) At room temperature S )-(-)-b-Methylphenethylamine is dissolved in hydrochloric acid solution and stirred at 100-200°C for 30-60 minutes to fully dissolve; (2) Bi at room temperature 2 O 3 Dissolve in hydrochloric acid solution and stir at 100-200℃ for 30-60min to fully dissolve.

[0038] In the above steps, heating and stirring are used to help dissolve the raw materials, reduce the amount of hydrochloric acid solution used, and thus reduce the time for the subsequent solution to evaporate.

[0039] Furthermore, the process of standing still for crystallization may be that after standing still for 120-240 minutes, crystal particles appear at the bottom of the container, and the standing still is continued to allow the crystals to grow until no more precipitation occurs.

[0040] Further, after standing and crystallizing, the following steps may also be included: Filter the solution, rinse the precipitated crystals with pure chlorobenzene, and dry them at room temperature.

[0041] The present application also provides the application of the above-mentioned nonlinear optical crystal, which can be used to convert the wavelength of the laser and has a wide transmission window. Therefore, the nonlinear optical crystal can be used to prepare nonlinear optical devices to provide a wider wavelength window for second-order nonlinear applications.

[0042] The present application is further described below through specific embodiments.

[0043] Example 1 Lead-free organic-inorganic perovskite crystals ( S -C 9 H 14 N) 4 Bi 2 Cl 10 , including the following steps: Weigh an appropriate amount of Bi 2 O 3 (466 mg, 1 mmol) was dissolved in hydrochloric acid solution (10 ml, 36-38 wt.% aqueous solution) and stirred at 100 °C for 30 min to fully dissolve; weigh an appropriate amount of ( S )-(-)-b-Methylphenylethylamine (541 mg, 4 mmol) was dissolved in hydrochloric acid solution (10 ml, 36-38 wt.% aqueous solution) and stirred at 100 ° C for 30 min to fully dissolve it; the above two solutions were mixed and stirred at 150 ° C for 120 min. After fully dissolved and mixed, they were naturally cooled to room temperature. After standing for 120 min, crystals precipitated. The solution was filtered out and the precipitated crystals were rinsed with pure chlorobenzene. After drying, lead-free organic-inorganic perovskite crystals ( S -C 9 H 14 N) 4 Bi 2 Cl 10 .

[0044] Figure 1 The lead-free organic-inorganic perovskite crystal in Example 1 ( S -C 9 H 14 N) 4 Bi 2 Cl 10Schematic diagram of Figure 2 The lead-free organic-inorganic perovskite crystal in Example 1 ( S -C 9 H 14 N) 4 Bi 2 Cl 10 The SEM image shows that the surface of the exfoliated crystal is smooth, confirming that the prepared lead-free organic-inorganic perovskite crystal ( S -C 9 H 14 N) 4 Bi 2 Cl 10 High crystallinity.

[0045] After testing, the lead-free organic-inorganic perovskite crystal prepared in Example 1 ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Belongs to the monoclinic system, space group is P2 1 , unit cell parameters are: a=11.8065 Å, b=25.4721 Å, c=32.3996 Å, α=γ=90°,β=91.332°,V=9741.1 Å 3 .

[0046] Figure 3 The lead-free organic-inorganic perovskite crystal in Example 1 ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Schematic diagram of the structure, with the large ( S )-(-)-b-methylphenylethylamine cation insertion, [Bi 2 Cl 10 ] 4- Edge-sharing dimers form and separate from each other, maintaining the electrical neutrality of the system. S )-(-)-b-methylphenylethylamine cation and [Bi 2 Cl 10 ] 4- The edge-sharing dimers interact with each other through NH…Cl hydrogen bonds to stabilize the structure, resulting in chiral transfer and BiCl 6 The asymmetric tilt and distortion of the octahedron provide a good structural foundation for the second-order nonlinear optical response.

[0047] Example 2 Synthesis of lead-free organic-inorganic perovskite crystals by anti-solvent precipitation method (S -C 9 H 14 N) 4 Bi 2 Cl 10 , including the following steps: Weigh an appropriate amount of Bi 2 O 3 (466 mg, 1mmol) was dissolved in hydrochloric acid solution (10ml, 36-38 wt.% aqueous solution), stirred at 100℃ for 30min to fully dissolve; weighed an appropriate amount of (S)-(-)-b-methylphenylethylamine (541 mg, 4mmol) and dissolved in hydrochloric acid solution (10ml, 36-38 wt.% aqueous solution), stirred at 100℃ for 30min to fully dissolve; the above two solutions were mixed, stirred at 150℃ for 60min, and cooled naturally to room temperature after they were fully dissolved and mixed. The above solutions were added drop by drop into pure chlorobenzene with magnetic stirring. After the addition was completed, the material precipitated in pure chlorobenzene was filtered and further rinsed with pure chlorobenzene. After drying, lead-free organic-inorganic perovskite crystals ( S -C 9 H 14 N) 4 Bi 2 Cl 10 .

[0048] Example 3 The lead-free organic-inorganic perovskite crystals ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Conduct XRD test: The D8 focus X-ray diffractometer was used to analyze the S -C 9 H 14 N) 4 Bi 2 Cl 10 X-ray diffraction analysis showed a pure phase. Figure 4 The lead-free organic-inorganic perovskite crystal ( S -C 9 H 14 N) 4 Bi 2 Cl 10 XRD pattern of .

[0049] Example 4 The lead-free organic-inorganic perovskite crystals ( S -C9 H 14 N) 4 Bi 2 Cl 10 To test through a window: Figure 5 The lead-free organic-inorganic perovskite crystal prepared in Example 1 ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Ultraviolet-near infrared transmission spectrum, the transmission range is: 0.33-3.0μm.

[0050] Example 5 The lead-free organic-inorganic perovskite crystals ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Perform second-order nonlinear optical response (frequency doubling) testing: Take appropriate amount ( S -C 9 H 14 N) 4 Bi 2 Cl 10 The crystal was placed in a sample cell with glass windows on both sides, and a 2090 nm Ho:Tm:Cr:YAG pulse laser was used as the light source to excite the sample. 2 The powder was used as a standard sample. The results showed that the lead-free organic-inorganic perovskite crystal ( S -C 9 H 14 N) 4 Bi 2 Cl 10 It can convert 2090 nm incident light into 1045 nm infrared laser output, with frequency doubling effect, and its frequency doubling performance is 0.029 times that of AgGaS 2 Quite, such as Figure 6 shown.

[0051] Example 6 The lead-free organic-inorganic perovskite crystals prepared in Example 2 ( S -C 9 H 14 N) 4 Bi 2 Cl 10 Conduct XRD test: The D8 focus X-ray diffractometer was used to analyze the S -C9 H 14 N) 4 Bi 2 Cl 10 X-ray diffraction analysis showed a pure phase. Figure 7 The lead-free organic-inorganic perovskite crystal ( S -C 9 H 14 N) 4 Bi 2 Cl 10 XRD pattern of .

[0052] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the scope of protection of the present application.

Claims

1. A nonlinear optical crystal, characterized in that: The chemical formula of the nonlinear optical crystal is ( S -C9H 14 N)4Bi2Cl 10 ; The nonlinear optical crystal belongs to the monoclinic system, the space group is P21, the unit cell parameters are a=11.8065 Å, b=25.4721 Å, c=32.3996 Å, α=γ=90°, β=91.332°, V=9741.1 Å 3 .

2. The nonlinear optical crystal according to claim 1, characterized in that: The nonlinear optical crystal is a translucent white crystal with a transmission range of 0.33-3.0 μm and a frequency doubling performance of 0.029×AgGaS2.

3. A method for preparing a nonlinear optical crystal according to any one of claims 1 to 2, characterized in that: The following steps are involved: Bi2O3 and ( S )-(-)-b-methylphenylethylamine as raw material, at room temperature S )-(-)-b-methylphenethylamine and the Bi2O3 are dissolved in a hydrochloric acid solution respectively, and after dissolution, the two are mixed, heated and stirred to volatilize part of the solvent, and crystals are precipitated to obtain the nonlinear optical crystal.

4. The method for preparing a nonlinear optical crystal according to claim 3, characterized in that: The process of heating and stirring to volatilize part of the solvent and precipitate crystals comprises the following steps: Heat and stir to volatilize part of the solvent, wait for the mixed solution to cool to room temperature in a supersaturated state, and stand to crystallize; The process of standing crystallization comprises the following steps: After standing for 120-240 minutes, crystal particles appear at the bottom of the container. Continue to stand to allow the crystals to grow until no more precipitation occurs. After the step of standing and crystallizing, the method further comprises the following steps: The solution was filtered off, and the precipitated crystals were washed clean with pure chlorobenzene and dried at room temperature.

5. The method for preparing a nonlinear optical crystal according to claim 3, characterized in that: The process of heating and stirring to volatilize part of the solvent and precipitate crystals comprises the following steps: The solvent is partially volatilized by heating and stirring. After the mixed solution is cooled to room temperature, the mixed solution is added dropwise into pure chlorobenzene with magnetic stirring. After the addition is completed, the substance precipitated in the pure chlorobenzene is filtered out, rinsed with pure chlorobenzene, and dried at room temperature.

6. The method for preparing a nonlinear optical crystal according to claim 3, characterized in that: At room temperature, the ( S The process of dissolving )-(-)-b-methylphenethylamine and the Bi2O3 in a hydrochloric acid solution respectively specifically comprises the following steps: At room temperature, the S )-(-)-b-methylphenethylamine is dissolved in the hydrochloric acid solution, and stirred at 100-200° C. for 30-60 min to fully dissolve it; Dissolve the Bi2O3 in the hydrochloric acid solution at room temperature, and stir at 100-200°C for 30-60 minutes to fully dissolve it; The mass concentration range of the hydrochloric acid solution is 36%-38%; The molar ratio between the Bi2O3 and the (S)-(-)-b-methylphenylethylamine is 1:2-4; For every 1mmol of Bi2O3, 10-20ml of hydrochloric acid solution is used, and for every 4mmol of ( S )-(-)-b-methylphenethylamine correspondingly uses 10-20 ml of the hydrochloric acid solution.

7. The method for preparing a nonlinear optical crystal according to claim 3, characterized in that: During the heating and stirring process to volatilize part of the solvent, the heating temperature is 120-200° C. and the stirring time is 1 h-2 h.

8. The method for preparing a nonlinear optical crystal according to claim 3, characterized in that: The molar ratio between the Bi2O3 and the (S)-(-)-b-methylphenylethylamine is 1:4; During the heating and stirring to volatilize part of the solvent, the heating temperature is 150°C.

9. Use of the nonlinear optical crystal according to any one of claims 1 to 2, characterized in that: The nonlinear optical crystal is used for preparing nonlinear optical devices.

Images