UiO-66 (at) Ag-Au-D / L-Cys composite material as well as preparation method and application thereof

Abstract

The invention belongs to the field of nonlinear optical materials, and discloses a UiO-66 (at) Ag-Au-D / L-Cys composite material as well as a preparation method and application of the UiO-66 (at) Ag-Au-D / L-Cys composite material. The composite material takes UiO-66 as a carrier, Ag-Au-D / L-Cys nanoparticles are uniformly distributed on the carrier, and the composite material has a chiral characteristic. The preparation method comprises the following steps: adding UiO-66 into a silver nitrate solution, and reacting to obtain a product I; the product I is placed in N, N-dimethylformamide for a reaction, and a product II is obtained; placing the product II in a D / L-cysteine solution for reaction to obtain a product III; placing the product III in a chloroauric acid solution to react to obtain a target product. The composite material disclosed by the invention realizes uniform dispersion of chiral Ag-Au-D / L-Cys nanoparticles on UiO-66, so that agglomeration of metal nanoparticles is avoided, the third-order nonlinear performance is enhanced, and the nonlinear performance can be effectively regulated and controlled.

Description

Technical Field

[0001] This invention belongs to the field of nonlinear optical materials, specifically relating to a UiO-66@Ag-Au- D / L -Cys composite materials, their preparation methods, and applications. Background Technology

[0002] Nonlinear optics (NLO) primarily studies the nonlinear optical effects generated by the interaction between lasers and matter. Third-order nonlinear optical materials, as core foundational materials of modern optics, exhibit irreplaceable application potential in numerous fields such as laser technology, optical signal processing, all-optical switching, and optical limiting. To enhance and flexibly control the performance of nonlinear optics and meet the application requirements of high-performance optical devices, the development and innovation of nonlinear optical materials has become a key research focus. Among existing materials, metal-organic frameworks (MOFs) provide an ideal platform for constructing high-performance nonlinear optical materials due to their ordered pore structure, excellent chemical stability, and flexibly tunable surface active sites. By utilizing heterogeneous interface engineering to precisely modify the chemical environment, and through the synergistic effect between the MOF support and the introduced photoresponsive chiral material, not only are the performance limitations of single components overcome, but the chiral characteristics also endow the material with special optical responses, enabling effective control of the material's nonlinear behavior under external laser irradiation. Summary of the Invention

[0003] In order to develop new nonlinear optical materials, the purpose of this invention is to provide a UiO-66@Ag-Au- D / L -Cys composite materials, their preparation methods, and applications.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A UiO-66@Ag-Au- D / L -Cys composite material, wherein the composite material uses UiO-66 as a carrier, on which Ag-Au- are uniformly distributed. D / L -Cys nanoparticles; the composite material has chiral characteristics.

[0005] A UiO-66@Ag-Au- D / L The preparation method of Cys composite material is as follows: (1) Add UiO-66 to silver nitrate solution, react at room temperature for 4-6 h, wash with water and centrifuge to obtain solid product I; (2) Place product I in N,N-dimethylformamide and react at room temperature for 2-3 hours. Then centrifuge directly to obtain powder product II. (3) Place product II in D / LIn a cysteine ​​solution, react at 30-40°C for 2-3 hours, wash with water and centrifuge to obtain solid product III; (4) Place product III in chloroauric acid solution and react at 40~50℃ for 2~3h. Wash with water and centrifuge to obtain the target product. Among them, silver nitrate solution is calculated based on the amount of silver it provides. D / L -Cysteine ​​solution with its provided D / L - Cysteine, chloroauric acid solution based on the provided gold element, raw material ratio is UiO-66: silver nitrate solution: N,N-dimethylformamide: D / L - Cysteine ​​solution : Chloroauric acid solution = (50~60) mg : (1~1.2) mmol : (10~12) mL : (3.5~3.7) × 10 -3 mmol: (9.2~9.4)×10 -3 mmol.

[0006] Preferably, the concentration of the silver nitrate solution is 0.1~0.12M.

[0007] Better D / L The concentration of the cysteine ​​solution was 3.5 × 10⁻⁶. -4 ~3.7×10 -4 M.

[0008] Preferably, the concentration of the chloroauric acid solution is 1.54 × 10⁻⁶. -3 ~1.56×10 -3 M.

[0009] A UiO-66@Ag-Au- D / L -Cys composite materials as third-order nonlinear optical materials.

[0010] In this invention, UiO-66 is a metal-organic framework (MOF) material composed of zirconium ions (Zr) and organic ligands, which can be prepared according to existing technologies.

[0011] Beneficial effects: The UiO-66@Ag-Au- described in this invention D / L -Cys enables chiral Ag-Au- D / L The uniform dispersion of Cys nanoparticles on UIO-66 effectively prevents the aggregation of metal nanoparticles; UiO-66@Ag-Au- D / L -Cys composite materials retain chiral characteristics, ensuring structural stability and performance consistency; under 532nm picosecond laser, UiO-66@Ag-Au- D / L -Cys composites exhibit stronger anti-saturation absorption and strong self-focusing refractive signals than single gold-silver alloys; UIO-66 and Ag-Au- D / L The synergistic effect of Cys overcomes the performance limitations of single components, and the special chiral optical response enhances the third-order nonlinear performance, significantly improving both the nonlinear absorption coefficient β and the nonlinear refractive index n2. This invention achieves effective control of nonlinear performance, UiO-66@Ag-Au- D / L Cys is an excellent third-order nonlinear optical material. Attached Figure Description

[0012] Figure 1 PXRD patterns for different samples.

[0013] Figure 2 The UiO-66@Ag-Au- obtained in Example 1 D -Cys low-magnification TEM image (a), high-magnification TEM image (b), and EDX mapping image (c).

[0014] Figure 3 The images show the UV-Vis absorption spectra (a) and FT-IR spectra (b) of different samples.

[0015] Figure 4 The UiO-66@Ag-Au- obtained in Example 1 D -Cys and the UiO-66@Ag-Au- obtained in Example 2 L -Circular dichroism (CD) spectrum of Cys.

[0016] Figure 5 The UiO-66@Ag-Au- obtained in Example 1 D -Cys and UiO-66, UiO-66@Ag-Au- obtained in Example 2 L -Cys thermogravimetric (TG) spectrum.

[0017] Figure 6 Z-scan curves of different samples under 532nm wavelength picosecond laser: (a) Z-scan curve with opening, (b) Z-scan curve with closing. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments without creative effort are within the protection scope of the present invention.

[0019] Example 1

[0020] UiO-66@Ag-Au- D-Synthesis steps of Cys composite materials: (1) Dissolve the raw materials zirconium tetrachloride (0.26 mmol), terephthalic acid (0.36 mmol) and benzoic acid (0.01 mol) in 4 mL of N,N-dimethylformamide. Place the reaction vessel containing the above solution in an oven at 120 °C and react for 24 h. Separate the reaction solution to obtain a white powder. Wash the obtained white powder three times with N,N-dimethylformamide and place it in an oven at 80 °C for 8 h to obtain UiO-66. (2) Add 50 mg UiO-66 to 10 mL of 0.1 M silver nitrate solution, react at room temperature for 4 h, wash with water and centrifuge to obtain solid product I; place product I in 10 mL of N,N-dimethylformamide, react at room temperature for 2 h, and centrifuge directly to obtain powder product II; place product II in 10 mL of 3.5 × 10⁻⁶ M silver nitrate solution. -4 M D The product was reacted in a cysteine ​​solution at 30°C for 2 hours, washed with water, and centrifuged to obtain solid product III; product III was then placed in 6 mL of a 1.56 × 10⁻⁶ solution. -3 The product UiO-66@Ag-Au- was obtained by reacting in M ​​chloroauric acid solution at 40°C for 2 hours, followed by washing with water and centrifugation three times. D -Cys composite material.

[0021] Example 2

[0022] UiO-66@Ag-Au- L -Synthesis steps of Cys composite materials: (1) Same as step (1) in Example 1; (2) Using “10mL concentration 3.5×10 -4 M L "-cysteine ​​solution" instead of "10 mL concentration 3.5 × 10" -4 M D "-cysteine ​​solution", and all other steps are the same as in Example 1 (2); the target product UiO-66@Ag-Au- is obtained. L -Cys composite material.

[0023] Comparative Example 1 Synthesis steps of UiO-66@Ag-Au-Cys composite material: (1) Same as step (1) in Example 1; (2) Using “5mL concentration 3.5×10 -4 M D - Cysteine ​​solution and 5 mL of 3.5 × 10 -4 M L "-cysteine ​​solution" instead of "10 mL concentration 3.5 × 10"-4 M D "-cysteine ​​solution", and the rest are the same as in Example 1, step (2); control product 1, namely UiO-66@Ag-Au-Cys composite material, was obtained.

[0024] Comparative Example 2 Ag-Au- D -Cys synthesis steps: First, add 5 mL of a 3.5 × 10⁻⁵ mL solution. -4 M D - Add cysteine ​​solution to 5 mL of deionized water at 30 °C, and immediately add 0.42 mL of 0.1 M AgNO3 solution and 2.4 mL of 0.1 M ascorbic acid solution while stirring continuously. Then add 3 mL of 1.56 × 10⁻⁶ solution. -3 M's HAuCl4 solution was added dropwise to the above solution. After the solution was completely mixed, it was placed in a 70°C water bath and stirred for 2 hours. Finally, the sample was separated by centrifugation and washed three times with water to remove free amino acids, finally obtaining control product 2, namely Ag-Au- D -Cys.

[0025] Comparative Example 3 Ag-Au- L The synthesis steps of Cys differ from those of Comparative Example 2 in that: a concentration of 3.5 × 10⁻⁵ mL was used. -4 M L "Cysteine ​​solution" instead of "5 mL concentration 3.5 × 10" -4 M D "-cysteine ​​solution", all other steps were the same as in Comparative Example 2, yielding control product 3, namely Ag-Au- L -Cys.

[0026] Comparative Example 4 The synthesis steps of Ag-Au-Cys differ from those in Comparative Example 2 in that: "2.5 mL concentration of 3.5 × 10" is used. -4 M D - Cysteine ​​solution and 2.5 mL of 3.5 × 10⁻⁶ solution -4 M L "Cysteine ​​solution" instead of "5 mL concentration 3.5 × 10" -4 M D "-cysteine ​​solution", and the rest were the same as in Comparative Example 2, to obtain Control Product 4, namely Ag-Au-Cys.

[0027] Structural characterization Figure 1 PXRD patterns of different samples, including UiO-66@Ag-Au- D-Cys was prepared in Example 1, UiO-66@Ag-Au- L -Cys was prepared in Example 2, UiO-66@Ag-Au-Cys was prepared in Comparative Example 1, and UiO-66 was prepared in step (1) of Example 1. Figure 1 It can be known that: UiO-66@Ag-Au- D -Cys、UIO-66@Ag-Au- L The results for -Cys and UiO-66@Ag-Au-Cys are consistent with the X-ray diffraction data of pure UiO-66 and standard cards of Ag and Au, demonstrating that UiO-66@Ag-Au-Cys... D / L Successful synthesis of -Cys and UiO-66@Ag-Au-Cys composite materials.

[0028] Figure 2 The UiO-66@Ag-Au- obtained in Example 1 D - Low-magnification TEM images (a), high-magnification TEM images (b), and EDX mapping images of Cys (c). (By...) Figure 2 (a) It can be seen that UiO-66 exhibits a regular octahedral structure, and its chiral Ag-Au- D -Cys nanoparticles exhibit a spherical morphology with similar particle size, Ag-Au- D Cys nanoparticles were uniformly dispersed on UiO-66 without significant aggregation. Figure 2 (b) It can be seen that the lattice spacing is 0.2120 nm, corresponding to Ag-Au- D -Cys (111) crystal plane; Figure 2 (c) shows the corresponding distribution of Au, Ag, Zr, C, O and S elements.

[0029] Spectral testing UV-Vis absorption spectroscopy: The sample was placed on a 10mm × 10mm quartz slide for UV-Vis absorption spectroscopy. FT-IR spectroscopy: The KBr pellet method was used, with measurements taken at 4000~400cm⁻¹. -1 The material was subjected to Fourier transform infrared (FT-IR) spectroscopy within the wavenumber range. Circular dichroism (CD) spectroscopy was performed using a circular dichroism spectrometer within the wavelength range of 200–800 nm at a test temperature of 25 °C.

[0030] Figure 3 The images show the UV-Vis absorption spectra (a) and FT-IR spectra (b) of different samples, where UiO-66@Ag-Au- D -Cys was prepared in Example 1, UiO-66@Ag-Au- L-Cys was prepared in Example 2, UiO-66@Ag-Au-Cys was prepared in Comparative Example 1, UiO-66 was prepared in step (1) of Example 1, Ag-Au- D -Cys was prepared for Comparative Example 2, Ag-Au- L -Cys was prepared in Comparative Example 3, and Ag-Au-Cys was prepared in Comparative Example 4. For example... Figure 3 As shown in (a), UiO-66 exhibits characteristic absorption in the 200–300 nm range, with Ag-Au- D / L -Cys and Ag-Au-Cys show broad absorption peaks across the entire wavelength range, UiO-66@Ag-Au- D / L Both -Cys and UiO-66@Ag-Au-Cys exhibit absorption in the aforementioned bands, indicating that UiO-66@Ag-Au- D / L Successful synthesis of -Cys and UiO-66@Ag-Au-Cys composite materials. Figure 3 As shown in (b), UiO-66@Ag-Au- D / L -Cys and UiO-66@Ag-Au-Cys retained all the characteristic peaks of UiO-66, with no significant peak shift and only slight changes in intensity, indicating good structural integrity; furthermore, at 1254 cm⁻¹... -1 The presence of a characteristic peak of -CN- in the vicinity indicates that Ag-Au- D / L The successful introduction of -Cys and Ag-Au-Cys in UiO-66.

[0031] Figure 4 The UiO-66@Ag-Au- obtained in Example 1 D -Cys and the UiO-66@Ag-Au- obtained in Example 2 L -Circular dichroism (CD) spectrum of Cys. (See attached image.) Figure 4 As shown, UiO-66@Ag-Au- D -Cys & UiO-66@Ag-Au- L -Cys exhibits symmetrical absorption peaks, indicating that UiO-66 reacts with Ag-Au- D / L -Cys composite materials exhibit excellent chiral optical properties.

[0032] Thermal stability test The thermal stability of the sample was tested by heating it from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere.

[0033] Figure 5 The UiO-66@Ag-Au- obtained in Example 1 D -Cys and UiO-66, UiO-66@Ag-Au- obtained in Example 2L -Cys thermogravimetric (TG) spectrum. (Example) Figure 5 As shown, UiO-66@Ag-Au- D / L -Cys has a thermal decomposition temperature of 450℃, indicating that UiO-66@Ag-Au- D / L -Cys composites exhibit high thermal stability.

[0034] Nonlinear absorption characteristic test In a glass vial, 3.5 g of anisole was added to 597 mg of PMMA and stirred at 70°C until completely dissolved, yielding solution A. 3 mg of the test sample was added to another glass vial containing 1 g of anisole and ultrasonically stirred until uniformly dispersed, yielding solution B. Solution B was added dropwise to solution A and stirred for 5 hours to form a homogeneous mixture. The mixed solution was then dropped onto a flat glass mold covered with a PET protective film. The flat glass mold was placed horizontally to allow the solvent to evaporate naturally until the mixture stopped flowing. The flat glass mold was then transferred to an oven and heated at 80°C for 4 hours to remove residual solvent from the film. After cooling, the resulting film was peeled off from the flat glass mold to obtain an optical-grade PMMA composite film containing 0.5 wt% of the target sample. The test samples were UiO-66@Ag-Au- D -Cys (prepared in Example 1), UiO-66@Ag-Au- L -Cys (prepared in Example 2), UiO-66@Ag-Au-Cys (prepared in Comparative Example 1), UiO-66 (prepared in step (1) of Example 1), Ag-Au- D -Cys (prepared in Comparative Example 2), Ag-Au- L -Cys (prepared in Comparative Example 3), Ag-Au-Cys (prepared in Comparative Example 4).

[0035] An optical-grade PMMA composite film containing 0.5 wt% of the target sample was placed on a stage. Picosecond Z-scan methods were used for open-aperture and closed-aperture Z-scan tests, and the data were fitted. Test conditions included: laser output wavelength of 532 nm, pulse width of 21 ps (FWHM), convex lens focal length of 300 mm, and laser energy at the focal point controlled within the range of 1.4–1.6 μJ. To avoid heat buildup in the sample, the repetition frequency was set to 10 Hz.

[0036] Figure 6 Z-scan curves of different samples under 532nm wavelength picosecond laser: (a) Z-scan curve with opening, (b) Z-scan curve with closing. Figure 6 (a) and Figure 6 (b) shows that different samples β The values ​​of n and n2 are as follows: UiO-66@Ag-Au- D -Cys β The value is 1.4 × 10 -10 mW -1 The value of n² is 2.2 × 10⁻⁶. -17 m 2 W -1 ; UiO-66@Ag-Au- L -Cys β The value is 1.44 × 10 -10 mW -1 The value of n² is 2.28 × 10⁻⁶. -17 m 2 W -1 ; UiO-66@Ag-Au-Cys β The value is 1.28 × 10 -10 mW -1 The value of n² is 2.0 × 10⁻⁶. -17 m 2 W -1 ; UiO-66 β The value is -3.3 × 10 -11 mW -1 The value of n² is -7 × 10 -18 m 2 W -1 ; Ag-Au- D -Cys β The value is 7.4 × 10 -11 mW -1 The value of n² is 1.1 × 10⁻⁶. -17 m 2 W -1 ; Ag-Au- L -Cys β The value is 7.8 × 10 -11 mW -1 The value of n² is 1.18 × 10⁻⁶. -17 m 2 W -1 ; Ag-Au-Cys β The value is 6.0 × 10 -11 mW -1 The value of n² is 8.5 × 10⁻⁶. -18 m 2 W -1 .

[0037] Since PMMA films exhibit no third-order nonlinear optical response, it is determined that the third-order nonlinearity at 532 nm laser wavelength is not due to the film substrate, but rather originates from the sample itself. UiO-66 displays saturated absorption response and self-defocusing refraction signal under 532 nm picosecond laser light. Ag-Au-Cys and Ag-Au- D -Cys and Ag-Au- L -Cys both exhibit anti-saturation absorption and self-focusing refractive signals; Ag-Au- D / L Loading UiO-66 with both Ag-Au-Cys and Ag-Au-Cys resulted in composite materials exhibiting enhanced anti-saturation absorption and self-focusing refractive signals. Furthermore, UiO-66@Ag-Au-Cys... D / L -Cys exhibits stronger antisaturation absorption and self-focusing refraction signal than UiO-66@Ag-Au-Cys.

[0038] The above embodiments are used to explain and illustrate this patent, and not to limit it. Any modifications and changes made to this patent within the spirit and scope of the claims shall fall within the protection scope of this patent.

Claims

1. A UiO-66@Ag-Au- D / L -Cys composite material, characterized by: The composite material uses UiO-66 as a carrier, on which Ag-Au- are uniformly distributed. D / L -Cys nanoparticles; the composite material has chiral characteristics.

2. A UiO-66@Ag-Au- as described in claim 1 D / L The method for preparing -Cys composite materials is characterized by, The steps are as follows: (1) Add UiO-66 to silver nitrate solution, react at room temperature for 4-6 h, wash with water and centrifuge to obtain solid product I; (2) Place product I in N,N-dimethylformamide and react at room temperature for 2-3 hours. Then centrifuge directly to obtain powder product II. (3) Place product II in D / L In a cysteine ​​solution, react at 30-40°C for 2-3 hours, wash with water and centrifuge to obtain solid product III; (4) Place product III in chloroauric acid solution and react at 40~50℃ for 2~3h. Wash with water and centrifuge to obtain the target product. Among them, silver nitrate solution is calculated based on the amount of silver it provides. D / L -Cysteine ​​solution with its provided D / L - Cysteine, chloroauric acid solution based on the provided gold element, raw material ratio is UiO-66: silver nitrate solution: N,N-dimethylformamide: D / L - Cysteine ​​solution : Chloroauric acid solution = (50~60) mg : (1~1.2) mmol : (10~12) mL : (3.5~3.7) × 10 -3 mmol: (9.2~9.4)×10 -3 mmol.

3. The UiO-66@Ag-Au- as described in claim 2 D / L The method for preparing Cys composite materials is characterized by: The concentration of the silver nitrate solution is 0.1~0.12M.

4. The UiO-66@Ag-Au- as described in claim 2 D / L The method for preparing Cys composite materials is characterized by: D / L The concentration of the cysteine ​​solution was 3.5 × 10⁻⁶. -4 ~3.7×10 -4 M.

5. The UiO-66@Ag-Au- as described in claim 2 D / L The method for preparing Cys composite materials is characterized by: The concentration of the chloroauric acid solution is 1.54 × 10⁻⁶. -3 ~1.56×10 -3 M.

6. A UiO-66@Ag-Au- as described in claim 1 D / L The application of Cys composite materials is characterized by: As a third-order nonlinear optical material.

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