Method for rapidly constructing large-area superlattice monolayer film, product and application thereof

Abstract

The invention discloses a method for rapidly constructing a large-area superlattice single-layer film and a product and application of the large-area superlattice single-layer film, and belongs to the technical field of nanometers.The method comprises the steps that nanoparticles in a nanoparticle solution are subjected to functional modification through perfluorinated molecules, and a mixed solution containing n-hexane is prepared; the mixed solution is injected into a water or alcohol solvent system for self-assembly, water-bath heating is assisted in the self-assembly process, the water-bath heating condition is 40-85 DEG C, and after n-hexane is completely volatilized, a nano-particle superlattice single-layer film is prepared on a liquid-liquid interface; the method is simple and controllable in process, high in preparation speed and good in universality, and the prepared nanoparticle superlattice monolayer film is good in orderliness and has a macroscopic large area.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and in particular to a method for rapidly constructing a large-area superlattice monolayer film, and a product and application thereof. Background Art

[0002] Superlattice is a periodic structure with regular and orderly arrangement. Superlattice film is a material with a crystal-like structure made by micro-nano processing technology. Compared with independent nanoparticles and disordered nanoparticle two-dimensional films, nanoparticle superlattice monolayer films show new collective properties and have excellent performance in plasma coupling, photoluminescence and magnetic flux bandgap, and are widely used in biosensors, flexible electronics, solar cells and other fields. The irregular arrangement of nanoparticles in disordered nanoparticle two-dimensional films forms uneven hot spot distribution, which will lead to poor uniformity of SERS signals and affect the repeatability of SERS detection results. Nanoparticle superlattice monolayer films can overcome this limitation.

[0003] Regarding noble metal nanoparticle superlattice monolayers, a lot of research has been done in the early stage, and a variety of effective strategies for preparing functional nanoparticle superlattices have been developed. However, there are still some problems with the traditional method of preparing nanoparticle superlattice monolayers. For example, the preparation process of high-quality superlattice structures is a process of weak force balance, and precise control cannot be achieved at present, so it is difficult to prepare large-area superlattice monolayers. In addition, since the process of functional modification of nanoparticles and the healing process of superlattice domains take a lot of time, it is impossible to achieve rapid preparation of superlattice monolayers. Therefore, how to maximize the reduction of self-assembly time and achieve large-area preparation is the main challenge facing the preparation of nanoparticle superlattice monolayers.

[0004] The Chinese patent document with publication number CN117488409A discloses a superlattice film of precious metal small nanoparticles and an assembly method and its application in SERS detection. The invention vigorously mixes precious metal nanoparticles with a toluene or n-hexane solution containing trace ligands to cause phase transfer, thereby obtaining a toluene or n-hexane solution containing precious metal nanoparticles; then the toluene or n-hexane solution containing precious metal nanoparticles is injected above the interface of ethylene glycol or diethylene glycol to form a liquid-air interface, and naturally evaporates to form a single-layer superlattice film, which is then optimized with ethanol. On the one hand, the time efficiency of this method needs to be improved, and on the other hand, this method can only be used to prepare superlattice films of precious metal small nanoparticles.

[0005] The Chinese patent document with publication number CN110899720A discloses a two-dimensional flexible noble metal nanoparticle superlattice film and its construction method and application. The invention uses gold-silver bimetallic nanobricks with high aspect ratio as the basic building unit, and modifies the high aspect ratio gold core-silver shell nanobricks with thiol-terminated hydrophobic polymers through a polymer-based ligand modification method, and then uses a gas-liquid interface self-assembly method to construct a two-dimensional flexible noble metal nanoparticle superlattice film. However, the superlattice film constructed by this method has a limited area. Summary of the invention

[0006] The present invention provides a method for rapidly constructing a large-area superlattice monolayer film, which has a simple and controllable process, a fast preparation speed, and good universality. The prepared nanoparticle superlattice monolayer film has good order and a macroscopically large area.

[0007] The specific technical solutions adopted are as follows:

[0008] A method for rapidly constructing a large-area superlattice monolayer film comprises the following steps:

[0009] (1) taking a nanoparticle solution, functionalizing the nanoparticles using perfluorinated molecules, and preparing a mixed solution containing n-hexane;

[0010] (2) injecting the mixed solution obtained in step (1) into a water or alcohol solvent system for self-assembly, and heating the self-assembly process in a water bath at a temperature of 40 to 85° C., and preparing a nanoparticle superlattice monolayer film at the liquid-liquid interface after the n-hexane is completely volatilized;

[0011] The nanoparticle solution includes but is not limited to a gold nanoparticle solution, a silver nanoparticle solution, a ferroferric oxide nanoparticle solution, a silicon nanoparticle solution, etc.;

[0012] The perfluorinated molecule is perfluorodecanethiol, perfluorodecanoic acid or perfluorooctyltriethoxysilane.

[0013] The method of the present invention utilizes perfluorinated molecules to carry out functional modification on nanoparticles, constructs an ultra-low surface energy microenvironment, and uses a temperature field to assist the self-assembly process in a specific solvent system, which not only maximizes the overcoming of the adsorption barrier and reduces the free energy of the system, but also effectively increases the effect of entropy and strengthens the assembly driving force. In addition, the ultra-low surface energy microenvironment constructed by the perfluorinated molecules also effectively avoids the thermal melting of the nanoparticles caused by the temperature field. Based on the synergistic effect of the perfluorinated molecules and the temperature field, the method of the present invention realizes the rapid construction of a large-area nanoparticle superlattice monolayer film, and the construction time can be shortened to within 120 minutes, can be 30 to 120 minutes, and further to 30 to 80 minutes.

[0014] Preferably, in step (1), the average particle size of the nanoparticles is 3 to 200 nm.

[0015] Optionally, the gold nanosphere solution is prepared from tert-butylamine borane complex (TBAB), gold chlorate, oleylamine and organic solvent as raw materials; the silver nanosphere solution is prepared from silver nitrate, oleylamine and organic solvent as raw materials; the ferrosoferric oxide nanoparticle solution can be directly purchased; and the silicon nanosphere solution is prepared from arginine, tetraethyl silicate (TEOS), ammonia water and organic solvent as raw materials.

[0016] Preferably, the mass fraction of the nanoparticles in the nanoparticle solution is 1-10 mg / mL, and the ratio of perfluorinated molecules to nanoparticles is 0.1-1 mmol:1 mg.

[0017] Preferably, when the nanoparticle solution is a gold nanosphere solution, a silver nanosphere solution or a ferroferric oxide nanoparticle solution, a n-hexane solution of perfluorodecanethiol or perfluorodecanoic acid is added to the nanoparticle solution to prepare a mixed solution containing n-hexane; when the nanoparticle solution is a silicon nanosphere solution, perfluorooctyltriethoxysilane is added to the nanoparticle solution, the solution is modified and then centrifuged, and then dispersed in a n-hexane-ethanol solution to prepare a mixed solution containing n-hexane.

[0018] Further preferably, in the n-hexane solution of perfluorodecanethiol or perfluorodecanoic acid, the concentration of perfluorodecanethiol or perfluorodecanoic acid is 10 to 300 mM. When the concentration of perfluoro molecules is too high, metal droplets will be generated during the assembly process and settle at the bottom of the beaker; when the concentration is too low, the constructed superlattice will have defects, multiple layers, and even nanoparticle melting.

[0019] Preferably, in step (2), the alcohol solvent is diethylene glycol.

[0020] The present invention also provides a nanoparticle superlattice monolayer film, which is prepared by the method for rapidly constructing a large-area superlattice monolayer film.

[0021] Optionally, the film area of ​​the nanoparticle superlattice monolayer film is 1 to 30 cm 2 , further 1 to 20 cm 2 , has a regularly and orderly arranged periodic structure, has good density, the nanoparticles are arranged in an orderly and dense manner, and have a macroscopic large area.

[0022] The present invention also provides the application of the nanoparticle superlattice monolayer film in the detection field. Specifically, the superlattice monolayer film can be used as a SERS substrate.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The method of the present invention utilizes perfluorinated molecules to functionalize nanoparticles, realizes the construction of an ultra-low surface energy microenvironment, and assists in the self-assembly process through a temperature field, thereby maximizing the overcoming of the adsorption barrier, reducing the free energy of the system, and effectively increasing the effect of entropy, strengthening the assembly driving force. In addition, the ultra-low surface energy microenvironment constructed by the perfluorinated molecules also effectively avoids the thermal melting of nanoparticles caused by the temperature field. Based on the synergistic effect of perfluorinated molecules and the temperature field, the method of the present invention realizes the rapid construction of a large-area superlattice monolayer film.

[0025] (2) The present invention adopts a one-step liquid-liquid interface self-assembly method to prepare a large-area nanoparticle superlattice monolayer film. The preparation method is simple, the preparation speed is fast, the cost is low, and the repeatability is good. The prepared nanoparticle superlattice monolayer film is easy to transfer, and the nanoparticles are arranged in an orderly and dense manner with good density. In addition, the method of the present invention has good universality and can be used not only for the preparation of precious metal nanoparticle superlattice monolayer films, but also for the preparation of ferroferric oxide nanoparticle superlattice monolayer films, silicon nanosphere superlattice monolayer films, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a TEM image of the gold nanospheres synthesized in Example 1.

[0027] Figure 2 This is a macroscopic film image of the gold nanoparticle superlattice monolayer film prepared by the one-step liquid-liquid interface self-assembly method in Example 1.

[0028] Figure 3 This is a TEM image of the gold nanoparticle superlattice monolayer film prepared by the one-step liquid-liquid interface self-assembly method in Example 1, wherein the scale bar in a is 500 nm and the scale bar in b is 50 nm.

[0029] Figure 4 This is a TEM image of the silver nanoparticle superlattice monolayer film prepared by the one-step liquid-liquid interface self-assembly method in Example 2, where the scale is 50 nm.

[0030] Figure 5 This is a TEM image of the ferroferric oxide nanoparticle superlattice monolayer film prepared by the one-step liquid-liquid interface self-assembly method in Example 3, where the scale is 50 nm.

[0031] Figure 6 This is a TEM image of a silicon nanosphere superlattice monolayer film prepared by a one-step liquid-liquid interface self-assembly method in Example 4, wherein the scale is 500 nm.

[0032] Figure 7 This is a macroscopic membrane image of the gold nanoparticle two-dimensional membrane constructed without perfluorodecanethiol induction in Example 1.

[0033] Figure 8This is a TEM image of the gold nanoparticle two-dimensional film constructed without perfluorodecanethiol induction in Comparative Example 1, wherein the scale bar in a is 500 nm and the scale bar in b is 50 nm.

[0034] Fig. 9 This is a TEM image of the two-dimensional film of gold nanoparticles induced by dodecanethiol in Comparative Example 1, wherein the scale bar in a is 1 μm and the scale bar in b is 50 nm. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the examples and drawings. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods in the following examples that do not specify specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer. Contents not described in detail in this specification belong to prior art known to professionals and technicians in the field.

[0036] Example 1

[0037] (1) Preparation of gold nanosphere solution

[0038] 10 mL of n-hexane, 10 mL of oleylamine and 98.5 mg of HAuCl 4 ·3H 2 O was mixed evenly, and the mixed solution was transferred to a three-necked flask, the rotation speed was 500 rpm to maintain the temperature at 15°C, and nitrogen was introduced; then 1 mL of n-hexane, 1 mL of oleylamine and 44 mg of tert-butylamine borane complex TBAB were quickly injected, and the temperature was maintained for 1 hour; then 60 mL of ethanol was added dropwise to the reaction solution under stirring, the reaction solution was centrifuged at 6000 rpm for 5 minutes, and redispersed in n-hexane to prepare a nano-gold sphere solution; the TEM image of the nano-gold sphere is shown in Figure 1 As shown, the average particle size is around 5 nm.

[0039] (2) Functionalization-Self-Assembly Film

[0040] Take 50 μL of the gold nanosphere solution (2.5 mg / mL) prepared in step (1), add 150 μL of 100 mM perfluorodecanethiol n-hexane solution, mix well, add n-hexane to make the volume 3 mL, and prepare a mixed solution containing n-hexane; add 25 mL of water in a beaker, inject the mixed solution containing n-hexane, cover with a breathable membrane, heat in a water bath at 50°C for self-assembly, wait for n-hexane to completely evaporate, and prepare a large transferable area (11 cm) at the liquid-liquid interface for 80 min. 2 ) Gold nanoparticle superlattice monolayer film.

[0041] The macroscopic film image of the gold nanoparticle superlattice monolayer is shown in Figure 2 As shown in the TEM images Figure 3As shown, where the scale bar in a is 500 nm and the scale bar in b is 50 nm, the constructed superlattice monolayer film has a large macroscopic area, a long-range orderly microscopic arrangement, and a close-packed hexagonal structure.

[0042] Example 2

[0043] (1) Preparation of silver nanosphere solution

[0044] Add 20 mL of oleylamine and 170 mg of silver nitrate into a three-necked flask, heat to 60°C under a nitrogen atmosphere, and stir at 700 rpm until the granular silver nitrate is completely dissolved; then quickly heat the solution (heating rate > 10°C / min) to 180°C, keep the temperature for 1 hour, and then cool the reaction system to room temperature; wash the obtained dark brown solution with 40 mL of acetone, and centrifuge at 8500 rpm for 8 minutes, disperse the solid matter in n-hexane, wash it again with acetone, centrifuge it at 2000 rpm for 5 minutes, and redisperse it in n-hexane to obtain a nanosilver sphere solution for stand-alone use, and the average particle size of the nanosilver spheres is around 10 nm.

[0045] (2) Functionalization-Self-Assembly Film

[0046] Take 100 μL of the silver nanosphere solution (1 mg / mL) prepared in step (1), add 300 μL of 50 mM perfluorodecanoic acid n-hexane solution, mix well, add n-hexane to make the volume 3 mL, and prepare a mixed solution containing n-hexane; add 25 mL of water in a beaker, inject the mixed solution containing n-hexane, cover with a breathable membrane, heat in a water bath at 40°C for self-assembly, wait for n-hexane to completely evaporate, and prepare a large transferable area (3 cm) at the liquid-liquid interface for 120 min. 2 )Silver nanoparticle superlattice monolayer film.

[0047] The TEM image of the silver nanoparticle superlattice monolayer is shown in Figure 2. Figure 4 As shown, where the scale bar is 50 nm, the constructed superlattice monolayer film has an ordered hexagonal close-packed structure.

[0048] Example 3

[0049] Take 150 μL of commercial ferroferric oxide nanoparticle solution (1 mg / mL, the average particle size of ferroferric oxide nanoparticles is 10 nm), add 1 mL of 50 mM perfluorodecanoic acid n-hexane solution, mix well, add n-hexane to make the volume 3 mL, and prepare a mixed solution containing n-hexane; add 25 mL of diethylene glycol in a beaker, inject the mixed solution containing n-hexane, cover with a breathable membrane, and heat in a water bath at 70 ° C for self-assembly. After the n-hexane is completely volatilized, a large transferable area (3 cm) is prepared at the liquid-liquid interface for 30 minutes. 2 )FeO3 nanoparticle superlattice monolayer film.

[0050] The TEM image of the FeO nanoparticle superlattice monolayer is shown in Figure 2. Figure 5 As shown, where the scale bar is 50 nm, the constructed superlattice monolayer film has an ordered hexagonal close-packed structure.

[0051] Example 4

[0052] (1) Preparation of silicon nanosphere solution

[0053] 87 mg of arginine was dissolved in 87 mL of water, and after stirring for 10 min, 5.55 mL of tetraethyl silicate TEOS was added, and the temperature was raised to 70°C for hydrolysis for 24 h to obtain a silica sphere seed solution; 40 μL of the silica sphere seed solution was added to a mixed solution containing 7 mL of water, 100 mL of ethanol and 4 mL of ammonia water, and after thorough mixing, 8 mL of TEOS was injected at a rate of 10 mL / min using a syringe pump, and magnetic stirring was performed for 12 h to obtain silica sphere colloidal particles; the silica sphere colloidal particles were washed with ethanol for 3 times and ultrasonically dispersed in ethanol to prepare a silica nanosphere solution for use, and the average particle size of the silica nanospheres was 200 nm.

[0054] (2) Functionalization-Self-Assembly Film

[0055] 100 μL of the silicon nanosphere solution (2.5 mg / mL) prepared in step (1) was added with 60 μL of perfluorooctyltriethoxysilane, mixed evenly, and modified at room temperature for 6 h; the modified solution was centrifuged at 6000 rpm for 5 min, and the separated solid matter was ultrasonically dispersed in 3 mL of n-hexane-ethanol solution (the volume ratio of n-hexane to ethanol was 14:1) to prepare a mixed solution containing n-hexane; 25 mL of water was added to a beaker, and the mixed solution containing n-hexane was injected, covered with a breathable membrane, and heated in a water bath at 50°C for self-assembly. After the n-hexane was completely evaporated, a large transferable area (6 cm) was prepared at the liquid-liquid interface for 80 min. 2 )Silicon nanosphere superlattice monolayer film.

[0056] The TEM image of the silicon nanosphere superlattice monolayer is shown in Figure 6 As shown, where the scale bar is 500 nm, the constructed superlattice monolayer film has a long-range ordered close-packed hexagonal structure.

[0057] Comparative Example 1

[0058] Take 50 μL of the newly prepared nano-gold sphere solution (2.5 mg / mL, 5 nm) in step (1) of Example 1, add n-hexane to make the volume 3 mL; add 25 mL of water in a beaker, inject the mixed solution containing gold spheres and n-hexane, cover with a breathable membrane, heat in a water bath at 50°C for self-assembly, wait for the n-hexane to completely evaporate, and prepare a two-dimensional film of gold nanoparticles at the liquid-liquid interface for 80 minutes.

[0059] The macroscopic film image of the gold nanoparticle two-dimensional film is shown in Figure 7 As shown in the TEM images Figure 8 As shown, where the scale bar in a is 500 nm and the scale bar in b is 50 nm, the constructed two-dimensional membrane has a limited area and a decreased orderliness. Single-layer, double-layer and even multi-layer structures appear at the microscopic level, and melting even occurs in local areas.

[0060] Comparative Example 2

[0061] Take 50 μL of the newly prepared nano-gold sphere solution (2.5 mg / mL, 5 nm) in step (1) of Example 1, add 150 μL of 10 mM dodecanethiol n-hexane solution, mix well, add n-hexane to make the volume 3 mL, and prepare a mixed solution containing n-hexane; add 25 mL of water in a beaker, inject the mixed solution containing gold spheres-n-hexane, cover with a breathable membrane, heat in a water bath at 50°C for self-assembly, wait for the n-hexane to completely evaporate, and prepare a two-dimensional film of gold nanoparticles at the liquid-liquid interface for 80 minutes.

[0062] The TEM image of the gold nanoparticle two-dimensional film is shown in Fig. 9 As shown, where the scale bar in a is 1 μm and the scale bar in b is 50 nm, the orderliness of the constructed two-dimensional film decreases, single-layer and double-layer structures appear at the microscopic level, and even melting occurs in local areas.

[0063] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for rapidly constructing a large-area superlattice monolayer film, characterized in that: The following steps are involved: (1) taking a nanoparticle solution, functionalizing the nanoparticles using perfluorinated molecules, and preparing a mixed solution containing n-hexane; (2) injecting the mixed solution obtained in step (1) into a water or alcohol solvent system for self-assembly, and heating the self-assembly process in a water bath at a temperature of 40 to 85° C., and preparing a nanoparticle superlattice monolayer film at the liquid-liquid interface after the n-hexane is completely volatilized; The nanoparticle solution includes a gold nanoparticle solution, a silver nanoparticle solution, a ferroferric oxide nanoparticle solution or a silicon nanoparticle solution; The perfluorinated molecule is perfluorodecanethiol, perfluorodecanoic acid or perfluorooctyltriethoxysilane.

2. The method for rapidly constructing a large-area superlattice monolayer film according to claim 1, characterized in that: In step (1), the average particle size of the nanoparticles is 3 to 200 nm.

3. The method for rapidly constructing a large-area superlattice monolayer film according to claim 1, characterized in that: The mass fraction of the nanoparticles in the nanoparticle solution is 1-10 mg / mL, and the ratio of the perfluorinated molecules to the nanoparticles is 0.1-1 mmol:1 mg.

4. The method for rapidly constructing a large-area superlattice monolayer film according to claim 1, characterized in that: When the nanoparticle solution is a nanogold ball solution, a nanosilver ball solution or a ferroferric oxide nanoparticle solution, a n-hexane solution of perfluorodecanethiol or perfluorodecanoic acid is added to the nanoparticle solution to prepare a mixed solution containing n-hexane; when the nanoparticle solution is a silicon nanosphere solution, perfluorooctyltriethoxysilane is added to the nanoparticle solution, the solution is modified and then centrifuged, and then dispersed in a n-hexane-ethanol solution to prepare a mixed solution containing n-hexane.

5. The method for rapidly constructing a large-area superlattice monolayer film according to claim 4, characterized in that: In the n-hexane solution of perfluorodecanethiol or perfluorodecanoic acid, the concentration of perfluorodecanethiol or perfluorodecanoic acid is 10 to 300 mM.

6. The method for rapidly constructing a large-area superlattice monolayer film according to claim 1, characterized in that: In step (2), the alcohol solvent is diethylene glycol.

7. A nanoparticle superlattice monolayer film, characterized in that: The superlattice is prepared by the method for rapidly constructing a large-area superlattice monolayer film as described in any one of claims 1-6.

8. The nanoparticle superlattice monolayer film according to claim 7, characterized in that: The film area of ​​the nanoparticle superlattice single layer film is 1 to 30 cm 2 .

9. Application of the nanoparticle superlattice monolayer film according to claim 7 or 8 in the field of detection.

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