A porphyrin-based two-dimensional graphyne nonlinear optical film material and its preparation and application

Abstract

The present invention relates to a porphyrin-based two-dimensional graphyne nonlinear optical thin film material and its preparation and application. By constructing an interface with a mutually immiscible aqueous phase and an organic phase, two monomers undergo a polymerization reaction at the interface under the action of a catalyst, thereby obtaining a large-scale defect-free two-dimensional graphyne nonlinear optical thin film material. Compared with the prior art, the catalyst system used in the present invention is highly efficient, and the obtained thin film material can be easily transferred to various substrates for subsequent device preparation. The optical limiting threshold of the porphyrin-based graphyne thin film material under ultrafast pulse laser conditions is significantly lower than that of most reported optical limiting materials, and has great application potential in the field of optical limiters.

Description

Technical Field

[0001] The invention belongs to the technical field of two-dimensional polymer nonlinear optical film materials, and relates to a porphyrin-based two-dimensional graphyne nonlinear optical film material and a preparation method and application thereof. Background Art

[0002] Graphdine (GDY), named for its structure similar to graphite and acetylene, is a new type of artificial two-dimensional carbon allotrope formed by two acetylene bonds (-C≡CC≡C-) between aromatic rings. Due to its unique electronic structure and extended π conjugated plane, Graphdine not only exhibits superior electronic properties, but also unique optical properties, which makes it considered as a potential nonlinear optical material. In 2019, Wu et al. cleverly applied this new material to nonlinear photon diodes and introduced another anti-saturation absorption material (SnS2). After combining these two two-dimensional materials in the form of liquid or film, non-reciprocal propagation of light was achieved. In 2020, Zhang et al. studied the broadband nonlinear absorption properties (ultraviolet to near-infrared, nanosecond and picosecond pulsed lasers) of Graphdine nanosheets obtained using liquid phase exfoliation technology. The study highlights the advantages of Graphdine nanosheets as optical limiters in the ultraviolet band. Recently, the saturation absorption properties of Graphdine have been further studied. At different laser excitation wavelengths of 475, 1060, 1550 and 1800 nm, graphyne exhibits wavelength-dependent saturation absorption characteristics and calculations show that graphyne has a significant β value (>1cm GW -1 ). This means that graphyne is very suitable as a passive mode locker to generate ultrashort laser pulses. However, compared with other two-dimensional materials (especially MOF and COF, which are also porous materials), graphyne is difficult to be used as an excellent nonlinear optical material. This may be because the monomer of graphyne is hexaethynylbenzene (HEB), which itself has almost no nonlinear optical activity. Therefore, designing a suitable monomer with nonlinear optical properties is the top priority to further improve the nonlinear optical response of graphyne itself.

[0003] Porphyrin is an important class of nonlinear optical functional molecules, characterized by a highly delocalized 18π electron system. Due to its large excited state absorption cross-section value, porphyrin molecules exhibit excellent reverse saturation absorption (RSA) response under nanosecond (ns) pulse excitation at visible light wavelengths. At the same time, the eight β-carbon atoms on the pyrrole ring of porphyrin and the four meso-carbon atoms that play a bridging role have high chemical reactivity, so it is easy to use these reactive sites to integrate porphyrin as a functional building block into a multifunctional nonlinear optical material. In recent years, MOF and COF materials with porphyrin molecules as ligands have received increasing attention in the field of nonlinear optics. However, related research in the field of graphyne is still blank. Studies have shown that porphyrin molecules connected by diacetylene bonds in the graphyne structure can expand the π conjugation effect of the system and enhance the interaction between molecules in the system, thereby further improving the two-photon absorption ability of the material. Considering the above factors, graphyne materials with porphyrin as a functional unit will have excellent nonlinear optical properties. At the same time, most graphyne is synthesized in powder form. When studying its third-order nonlinear optics, the powder usually needs to be dispersed in an organic solvent, which is prone to powder agglomeration and deposition during the test, causing the sample to scatter into the laser, which limits its application in nonlinear optics.

[0004] Currently, it is still a major challenge to prepare large-area, uniform-thickness, two-dimensional graphyne films with nonlinear optical properties. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a porphyrin-based two-dimensional graphyne nonlinear optical film material and its preparation and application, which has a two-dimensional film structure and an ultra-large conjugated plane; at the same time, the nonlinear optical material can be further prepared into a device, which exhibits good nonlinear optical absorption phenomenon under the excitation of ultrafast laser.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In one aspect, the present invention provides a method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material, comprising the following steps:

[0008] (1) weighing monomers 5,10,15,20-(tetrakis-4-ethynylphenyl)porphyrin and tetrakis(triphenylphosphine)palladium, dissolving them in dichloromethane to obtain an organic phase;

[0009] (2) adding an aqueous solution containing cuprous chloride to the organic phase obtained in step (1), allowing the mixture to stand for polymerization to obtain a crude product, which is then washed to obtain the target product.

[0010] Furthermore, in step (1), the ratio of the added amounts of 5,10,15,20-(tetrakis-4-ethynylphenyl)porphyrin, tetrakis(triphenylphosphine)palladium and dichloromethane is (3-10) mg: (0.5-2) mg: (50-200) mL.

[0011] Furthermore, in step (2), the ratio of cuprous chloride to water is (1-10) mg: (20-50) mL.

[0012] Furthermore, in step (2), the amount of organic phase added satisfies: the mass ratio of 5,10,15,20-(tetra-4-ethynylphenyl)porphyrin to cuprous chloride is (4-6):1.

[0013] Furthermore, in step (2), the polymerization reaction temperature is 20 to 50°C.

[0014] Furthermore, in step (2), the polymerization reaction time is 3 to 5 days.

[0015] Furthermore, in step (2), the washing process is specifically as follows:

[0016] The product was repeatedly washed with organic solvent and distilled water and filtered until the filtrate was colorless.

[0017] Furthermore, in step (2), the organic solvent is selected from one or more of methanol, acetone, dichloromethane, N,N-dimethylformamide, tetrahydrofuran, petroleum ether or N-methylpyrrolidone.

[0018] In a second aspect, the present invention provides a porphyrin-based two-dimensional graphyne nonlinear optical thin film material, which is prepared by any of the preparation methods described above, and is characterized in that it has an extended conjugated structure and an ultrathin nanosheet morphology.

[0019] In a third aspect, the present invention also provides the use of porphyrin-based two-dimensional graphyne nonlinear optical film materials in the construction of ultrafast laser response devices.

[0020] Furthermore, the ultrafast laser response device is applicable to an ultrafast laser waveband of 400 to 2000 nm.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. Compared with traditional optically sensitive materials, the porphyrin-based two-dimensional graphyne nonlinear optical thin film material prepared in the present invention has a very high conjugation property, provides sufficient space for electron delocalization, has a very wide optical absorption band, and is conducive to generating ultrafast laser response.

[0023] 2. The catalyst system used in the thin film preparation process of the present invention can efficiently catalyze porphyrin monomers to form large-scale defect-free thin film materials, and the obtained thin film materials can be easily transferred to various substrates for device preparation, such as quartz glass, silicon wafers, glass slides, cover glass, and optical fibers.

[0024] 3. The present invention uses the porphyrin-based two-dimensional graphyne film for the first time to construct an ultrafast laser response device, and exhibits good nonlinear optical properties, which can be used for broadband optical limiting applications of ultrafast laser response. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the synthesis of the porphyrin-based graphyne nonlinear optical thin film material prepared by the present invention;

[0026] Figure 2 A scanning electron microscope (SEM) image of the porphyrin-based graphyne nonlinear optical thin film material prepared by the present invention;

[0027] Figure 3 The infrared spectrum of the porphyrin-based graphyne nonlinear optical thin film material prepared by the present invention;

[0028] Figure 4 The ultraviolet absorption diagram of the porphyrin-based graphyne nonlinear optical thin film material prepared by the present invention;

[0029] Figure 5 The nonlinear optical absorption diagram of the porphyrin-based graphyne nonlinear optical thin film material prepared by the present invention;

[0030] Figure 6 This is a diagram of the optical limiting performance of the porphyrin-based graphyne nonlinear optical thin film material prepared by the present invention;

[0031] Figure 7 This is a scanning electron microscope image of the material of Comparative Example 1;

[0032] Figure 8 is a scanning electron microscope image of the material of Example 2;

[0033] Fig. 9 This is a scanning electron microscope image of the material of Example 3. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0035] In the following examples, unless otherwise specified, raw materials, products or processing techniques are all conventional commercially available products or conventional processing techniques in the art.

[0036] Embodiment 1:

[0037] Reference Figure 1 The process flow shown in FIG. 1 is a process for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material.

[0038] (1) Add 5 mg of 5,10,15,20-(tetrakis-4-ethynylphenyl)porphyrin and 1 mg of tetrakis(triphenylphosphine)palladium to 50 mL of dichloromethane, and then pour into a 150 mL beaker with a diameter of 5 cm;

[0039] (2) Add 1 mg of CuCl to 40 mL of deionized water, then slowly add the solution into a beaker to cover the dichloromethane layer to form a two-phase system. Perform the interfacial reaction at room temperature for 72 hours;

[0040] (3) After the aqueous solution and the organic solution were drained, the film was transferred to a quartz substrate, then rinsed with deionized water and acetone several times to remove the residual monomer, and dried in an oven at 60°C for 12 hours for subsequent testing.

[0041] Comparative Example 1:

[0042] In Comparative Example 1, the porphyrin-based graphyne film of the present invention was synthesized using a classic catalyst system for synthesizing graphyne powder, specifically, tetrakis(triphenylphosphine)palladium was replaced by pyridine, cuprous chloride was replaced by cupric acetate, and other conditions remained unchanged. The final product obtained had poor film-forming properties, as shown in FIG. Figure 7 .

[0043] Comparative Example 2:

[0044] Compared with Example 1, most of the steps are the same except that the aqueous phase does not contain cuprous chloride.

[0045] Comparative Example 3:

[0046] Compared with Example 1, most of the conditions are the same except that the organic phase does not contain tetrakis(triphenylphosphine)palladium.

[0047] Product characterization and performance testing

[0048] Figure 2 A scanning electron microscope (SEM) photograph of the porphyrin-based graphyne nonlinear optical thin film material prepared in Example 1 of the present invention is provided, from which it can be seen that the surface is obviously smooth and the two-dimensional sheet and layer structure is complete.

[0049] Figure 3 The infrared spectrum of the porphyrin-based graphyne nonlinear optical thin film material prepared in Example 1 of the present invention is given. For the porphyrin monomer, at 3280 cm -1There is a sharp characteristic peak at 2103 cm -1 The characteristic peak at 3280cm is a typical C≡C stretching vibration. -1 The strong peak at 2103 cm-1 almost completely disappeared, indicating that the alkynyl hydrogen atom at the end of the porphyrin participated in the coupling reaction and had a very high conversion rate. -1 The stretching vibration peak of C≡C completely disappears in the PDY film, which can be attributed to the formation of symmetrical diacetylene bonds (C≡CC≡C).

[0050] Figure 4 The ultraviolet absorption spectrum of the porphyrin-based graphyne nonlinear optical film material prepared in Example 1 of the present invention is given. When the TEPP monomer undergoes polymerization to form the PDY film, the Soret band of the porphyrin undergoes an obvious red shift from 420nm to 432nm. The four weaker Q band absorption peaks also red shift to 534, 568, 607, and 659nm, respectively. The obvious red shift of the Soret band absorption peak and the Q band absorption peak is related to the expanded π conjugated system of the PDY film.

[0051] Figure 5 The nonlinear optical absorption spectrum of the porphyrin-based graphyne nonlinear optical thin film material prepared in Example 1 of the present invention is given. Under different excitation wavelengths, the prepared thin film materials all exhibited obvious energy-dependent anti-saturation absorption behavior.

[0052] Figure 6 The optical limiting performance diagram of the porphyrin-based graphyne nonlinear optical thin film material prepared in Example 1 of the present invention is given. After fitting, the optical limiting threshold of the film at 515nm is 4393μJ cm -2 , and its optical limiting threshold at 800 nm is 3050 μJ cm -2 The optical limiting thresholds at the two wavelengths are significantly smaller than those of most reported optical limiting materials (e.g. Figure 6 c), indicating its great potential in the field of optical limiting.

[0053] Figure 7 This is a scanning electron microscope image of the material of Comparative Example 1 prepared in the present invention. It can be seen from the image that no obvious film morphology is formed, which verifies the superiority of the catalyst system used in the present invention.

[0054] Figure 8 This is a scanning electron microscope image of the material of Comparative Example 2 prepared by the present invention. It can be seen from the image that no obvious film morphology is formed, indicating that a single tetrakis(triphenylphosphine)palladium catalyst cannot catalyze the monomer to form a film.

[0055] Fig. 9 This is a scanning electron microscope image of the material of Comparative Example 3 prepared in the present invention. It can be seen from the image that no obvious film morphology is formed, indicating that a single cuprous chloride catalyst cannot catalyze the monomer to form a film.

[0056] In general, the present invention constructs an interface with an immiscible aqueous phase and an organic phase, and under the action of a catalyst, two monomers undergo a polymerization reaction at the interface to obtain a large-scale defect-free two-dimensional graphyne nonlinear optical thin film material. Compared with the prior art, the catalyst system used in the present invention is highly efficient, and the obtained thin film material can be easily transferred to various substrates for subsequent device preparation. The optical limiting threshold of the porphyrin-based graphyne thin film material under ultrafast pulse laser conditions is significantly lower than that of most reported optical limiting materials, and has great application potential in the field of optical limiters.

[0057] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and 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 present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material, characterized in that: The following steps are involved: (1) Weighing monomers 5,10,15,20-(tetrakis-4-ethynylphenyl)porphyrin and tetrakis(triphenylphosphine)palladium, dissolving them in dichloromethane, and obtaining an organic phase; (2) Adding an aqueous solution containing cuprous chloride to the organic phase obtained in step (1), allowing the mixture to stand for polymerization reaction to obtain a crude product, which is then washed to obtain the target product.

2. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 1, characterized in that: In step (1), the ratio of the added amounts of 5,10,15,20-(tetrakis-4-ethynylphenyl)porphyrin, tetrakis(triphenylphosphine)palladium and dichloromethane is (3-10) mg: (0.5-2) mg: (50-200) mL.

3. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 1, characterized in that: In step (2), the ratio of cuprous chloride to water is (1-10) mg: (20-50) mL.

4. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 1, characterized in that: In step (2), the amount of organic phase added satisfies the following conditions: the mass ratio of 5,10,15,20-(tetra-4-ethynylphenyl)porphyrin to cuprous chloride is (4-6):

1.

5. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 1, characterized in that: In step (2), the polymerization reaction temperature is 20-50 °C.

6. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 1, characterized in that: In step (2), the polymerization reaction time is 3 to 5 days.

7. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 1, characterized in that: In step (2), the washing process is specifically as follows: The product was repeatedly washed with organic solvent and distilled water and filtered until the filtrate was colorless.

8. The method for preparing a porphyrin-based two-dimensional graphyne nonlinear optical thin film material according to claim 7, characterized in that: In step (2), the organic solvent is selected from methanol, acetone, dichloromethane, N ,N - dimethylformamide, tetrahydrofuran, petroleum ether or N -One or more of methyl pyrrolidone.

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