Preparation method of silver nanowire based on phenolic compound and silver nanowire

Abstract

The invention relates to a preparation method of a silver nanowire based on a phenolic compound and the silver nanowire, and the preparation method comprises the following steps: 1, respectively dissolving polyvinylpyrrolidone, small molecular phenolic acid, halide, a silver source and the phenolic compound in deionized water to obtain respective solutions; 2, sequentially adding a polyvinylpyrrolidone solution, a small molecular phenolic acid solution, a halide solution and a silver source solution, and stirring to obtain a reaction solution A; step 3, adding a phenolic compound solution into the reaction solution A to obtain a reaction system B, and stirring and reacting to obtain a mixed solution C containing silver nanowires; fourthly, the mixed solution C containing the silver nanowires is sequentially centrifuged and washed, and then the silver nanowires are prepared; the diameter of the silver nanowire is 20-150 nm, and the length of the silver nanowire is 5-100 [mu] m. Therefore, according to the design, water is adopted as a solvent to synthesize the silver nanowire, the reaction temperature is low, and the reaction speed is high.

Description

Technical Field

[0001] The invention relates to a preparation method of silver nanowires and the silver nanowires, belonging to the field of optoelectronic technology, and in particular to a preparation method of silver nanowires based on phenolic compounds and the silver nanowires. Background Art

[0002] Transparent conductive film (TCF) plays an indispensable role in display panels, touch screens, solar cells and other fields due to its excellent transparency and conductivity. The traditional TCF material, indium tin oxide (ITO), is well-known for its excellent electrical and optical properties. However, its brittleness and poor adhesion to the substrate have become the key bottleneck restricting its application in flexible and bendable electronic devices.

[0003] As an emerging material, silver nanowires are considered an ideal alternative to ITO due to their excellent electro-optical properties, excellent mechanical flexibility and simple manufacturing process, especially showing great development potential in flexible and bendable displays. In addition, silver nanowires have also been widely used in many other fields due to their unique physical and chemical properties: In the field of optics, silver nanowires are not only suitable for various types of solar cells (such as thin films deposited on crystalline silicon, PET or glass), but also play an important role in medical imaging technology (such as surface-enhanced Raman spectroscopy) and surface plasmon devices.

[0004] In terms of conductive materials, it is used in high-brightness LEDs (as a conductive adhesive), touch screens (such as computers and tablets), liquid crystal displays, and various sensors.

[0005] In antimicrobial applications, silver nanowires can be used for air purification and water treatment (such as the purification process of sterile equipment), and also support the development of medical antibacterial measures and food preservation technology.

[0006] In the fields of chemistry and thermodynamics, silver nanowires can be used as catalysts, basic materials for chemical vapor sensors, and are also of great significance in the research of conductive polymers.

[0007] Silver nanowires are nanoscale linear structures made of silver materials. Currently, the preparation methods of silver nanowires include polyol method, seed growth method, solvothermal method and template method, among which the most widely used are polyol method, hydrothermal method and solvothermal synthesis method. However, these methods need to be carried out under high temperature and high pressure conditions, the reaction time is long, and the solvents used are organic solvents, which are not environmentally friendly and easily cause environmental pollution problems. At the same time, the generated silver nanowires have low purity and low yield.

[0008] The Chinese patent application with application number 202111012877.9 and application date August 31, 2021 discloses a silver nanowire containing polyphenol compounds, a preparation method and application thereof; the raw materials for preparing the silver nanowire containing polyphenol compounds include: polyvinyl pyrrolidone, bromine salt, silver salt and polyphenol compounds, based on the typical polyol synthesis of silver nanowires, introducing polyphenol compounds as reducing agents to accelerate the reduction rate of the reaction. Although the patent can generate silver nanowires with smaller diameters at lower temperatures, it still has the following defects: This design uses organic solvents to synthesize silver nanowires and the reaction rate is slow.

[0009] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of this patent application, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0010] The purpose of the present invention is to overcome the defects and problems of the prior art that silver nanowires are synthesized using organic solvents and have a slow reaction speed, and to provide a method for preparing silver nanowires based on phenolic compounds and silver nanowires that use water as a solvent and have a fast reaction speed.

[0011] To achieve the above objectives, the technical solution of the present invention is: a method for preparing silver nanowires based on phenolic compounds and silver nanowires, the method for preparing silver nanowires comprising the following steps: The first step: using polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound as solutes and deionized water as solvent, first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound in deionized water respectively, and stirring evenly to obtain polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution, and phenolic compound solution; Step 2: first, add the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution prepared in the first step into a container in sequence, and stir at room temperature until the solution turns light yellow, then stop stirring to obtain a reaction solution A; Step 3: first add the phenolic compound solution prepared in the first step to the above reaction solution A to obtain a reaction system B, and stir at room temperature to allow the reaction system B to undergo an oxidation-reduction reaction for 1-3 hours, until the reaction system B changes from light yellow to grayish yellow green and there are obvious layered floccules when shaken, then stop stirring to obtain a mixed solution C containing silver nanowires; Step 4: Centrifuge and wash the mixed solution C containing silver nanowires to obtain silver nanowires.

[0012] In the first step, the silver source is silver nitrate, and the silver source solution is silver nitrate solution; The mass ratio of the polyvinyl pyrrolidone solution, the small molecule phenolic acid solution, the halide solution, the silver nitrate solution and the phenolic compound solution is 50-400: 1.68-34: 0.05-1.35: 0.535-21.6: 0.055-37.8.

[0013] In the first step, the phenolic compound is any one of phloroglucinol, catechol, resorcinol and hydroquinone; When the phenolic compound is phloroglucinol, the concentration of the phenolic compound solution is 0.126 mg / ml-37.8 mg / ml; when the phenolic compound is catechol, resorcinol or hydroquinone, the concentration of the phenolic compound solution is 0.055 mg / ml-33 mg / ml.

[0014] In the first step, the small molecule phenolic acid is gallic acid or caffeic acid; The concentration of the small molecule phenolic acid solution is 1.68 mg / ml-34 mg / ml.

[0015] In the first step, the molecular weight of the polyvinyl pyrrolidone is any one of 10000, 40000, and 800000; The concentration of the polyvinyl pyrrolidone solution is 50 mg / ml-400 mg / ml.

[0016] In the first step, the halide is a compound containing Cl - or Br - Ionic compounds; The concentration of the halide solution is 0.05 mg / ml-1.35 mg / ml.

[0017] In the first step, the molar amount of silver nitrate is 0.05 mmol-0.2 mmol; The concentration of silver ions in the silver nitrate solution is 0.535 mg / ml-21.6 mg / ml.

[0018] In the first step, the step of first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source and phenolic compound in deionized water respectively and stirring them uniformly means: first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide and phenolic compound in deionized water respectively and dissolving them under ultrasound, dissolving the silver source in deionized water and dissolving them at room temperature, and then respectively stirring the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution and phenolic compound solution uniformly; In the second step, the stirring at room temperature refers to: stirring at a stirring rate of 500-1500 rpm, at a temperature of 30° C., for 0-10 minutes; In the third step, stirring at room temperature means: stirring at a stirring rate of 500-1500 rpm, at a temperature of 30° C., for 1-3 hours.

[0019] In the fourth step, the step of centrifuging and washing the mixed solution C containing silver nanowires in sequence to obtain silver nanowires means: centrifuging the mixed solution C containing silver nanowires using a high-speed desktop centrifuge to obtain a precipitate containing silver nanowires, and then washing the precipitate containing silver nanowires with deionized water to obtain silver nanowires, the washing number of times being at least once; and then ultrasonically dispersing the silver nanowires to obtain uniformly dispersed silver nanowires.

[0020] The silver nanowires are made by the method for preparing silver nanowires based on phenolic compounds as described in any one of claims 1 to 7; The silver nanowire has a diameter of 20-150 nm and a length of 5-100 μm.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. A method for preparing silver nanowires based on phenolic compounds and the silver nanowires, wherein polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound are used as solutes, and deionized water is used as solvent, and the mixture is stirred at room temperature to allow the reaction system B to undergo an oxidation-reduction reaction for 1-3 hours. When used, polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound are respectively dissolved in deionized water, stirred evenly to obtain corresponding solutions, and then polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, and silver source solution are sequentially added to obtain a reaction solution A, and the reaction is carried out at room temperature for 1-3 hours to obtain a mixed solution containing silver nanowires. Deionized water is used as a solvent, which is more environmentally friendly and has lower cost than an organic solvent. At the same time, small molecule phenolic acid and phenolic compound are used as reducing agents together to react at room temperature for 1-3 hours to generate silver nanowires, and high temperature and high pressure environments are not required, and the reaction speed is faster. Therefore, the present invention can not only produce silver nanowires, but also uses water as a solvent, so the reaction temperature is low and the reaction speed is fast.

[0022] 2. A method for preparing silver nanowires based on phenolic compounds and the silver nanowires, wherein the mass ratio of polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver nitrate solution and phenolic compound solution is 50-400: 1.68-34: 0.05-1.35: 0.535-21.6: 0.055-37.8; when used, the prepared polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver nitrate solution and phenolic compound solution are five solutions, the phenolic compound solution and the small molecule phenolic acid solution are used as reducing agents, the oxygen atom on the phenolic hydroxyl group in the phenolic compound contains a lone pair of electrons, which can interact with silver ions and reduce them to silver atoms, the carboxyl group (-COOH) contained in the small molecule phenolic acid is an electron-withdrawing group, which can reduce the electron density on the phenolic hydroxyl group in the phenolic compound and enhance the electrophilicity of its oxygen atom, and this electron-withdrawing effect makes the OH bond on the phenolic hydroxyl group easier to break The silver ions are further split, which is more conducive to the transfer of electrons and the reduction reaction. That is to say, the presence of phenolic acid molecules promotes the transfer of electrons from phenolic compounds to silver ions, making the reduction of silver ions more efficient. Generally, phenolic compounds have strong reducing ability, and small molecule phenolic acids regulate this process through their electron-withdrawing effect. Therefore, by adjusting the concentration or content ratio of small molecule phenolic acids and phenolic compounds, the reduction rate of silver ions can be accurately controlled. This regulation helps to finely adjust the growth process of silver nanowires, thereby affecting the morphology of silver nanowires, especially their aspect ratio (the ratio of the length of the nanowire to the diameter). Therefore, the present invention not only has a faster reaction speed, but also has a controllable aspect ratio of the silver nanowires.

[0023] 3. A preparation method of silver nanowires based on phenolic compounds and silver nanowires. The traditional method for making silver nanowires is the polyol method. In addition to generating silver nanowires during the preparation process, this method also generates many spherical solid small particles. It is necessary to remove the solid small particles through a purification step to obtain silver nanowires with higher purity. The purification technology mainly includes multi-step centrifugal filtration, fiber membrane filtration, decantation and cross-flow filtration. These purification methods are cumbersome to operate, have many steps, low purification efficiency, require a lot of time and solvent, and are prone to produce solid precipitation. Compared with the polyol method, the present invention has a higher purity of silver nanowires, which can reach 98% to 99.5%, and almost no free small particles are generated, so the purification operation is simpler and avoids complicated purification and impurity removal processes. Therefore, the present invention not only produces silver nanowires with higher purity, but also simplifies the purification and impurity removal steps in the production process.

[0024] 4. A method for preparing silver nanowires based on phenolic compounds and the silver nanowires, wherein polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution are sequentially added, stirred and then the phenolic compound solution is added, stirred and reacted to obtain a mixed solution C containing silver nanowires, and then the mixed solution C is centrifuged and washed to obtain silver nanowires, and the diameter of the obtained silver nanowires is 20-150nm and the length is 5-100μm; when used, polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution are sequentially added and stirred to make each component evenly distributed to obtain a reaction solution A, and then the phenolic compound solution is added to the reaction solution A to obtain a reaction system B and stirred, wherein the phenolic compound and the small molecule phenolic acid in the reaction system B are used as reducing agents to reduce the silver ions (Ag + ) is reduced to silver atoms (Ag 0 ), silver atoms will spontaneously form clusters (1-5nm) and form quintuple twins on the surface of tiny particles. These quintuple twins will gradually sprout and grow along a specific direction (usually

[100] or

[111] crystal direction) to form silver rods under the traction of halogen ions in the halide, and continue to grow into silver wires under the action of the surface protectant polyvinyl pyrrolidone (PVP). The right amount of halogen helps to fix silver atoms. The amount of surface protectant polyvinyl pyrrolidone is also crucial to the growth of silver nanowires, which affects the growth direction of silver atoms and the shape of silver nanowires. , adding polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution, and phenolic compound solution in sequence is beneficial to reduce unnecessary particle formation in the reaction, and stirring the reaction system B at a uniform speed makes the ions in the reaction system fully contact and evenly dispersed, which is beneficial to the directional growth of silver nanowires. Finally, the diameter of the prepared silver nanowires is 20-150nm, the length is 5-100μm, and the aspect ratio is in the range of 33.33-5000. The aspect ratio range is wide and the aspect ratio is high. The aspect ratio range is wide and can meet a variety of application scenarios. Therefore, the present invention not only generates a wide range of silver nanowire aspect ratios, but also generates a high aspect ratio of silver nanowires.

[0025] 5. A preparation method of silver nanowires based on phenolic compounds and silver nanowires, wherein the phenolic compound is any one of phloroglucinol, catechol, resorcinol and hydroquinone, and the small molecule phenolic acid is gallic acid or caffeic acid; when used, the phenolic compound and the small molecule phenolic acid are used as reducing agents to participate in the generation of silver nanowires, and the small molecule phenolic acid is gallic acid or caffeic acid, which belongs to plant polyphenols, not only has a wide source, but also is green and non-toxic, and replaces traditional harmful chemicals in the synthesis process, making the entire preparation process more environmentally friendly and sustainable, and the phenolic compound is phloroglucinol, catechol, resorcinol and hydroquinone, and the reducing property of the phenolic compound is stronger than that of the traditional alcohol reducing agent, and an effective reduction reaction can be carried out at a lower temperature, thereby controlling the growth rate and size of the silver nanowires, promoting the formation of the silver nanowires, and not needing to synthesize the silver nanowires under high temperature and high pressure conditions, which not only saves energy, but also reduces the energy consumption of the entire preparation process. Therefore, the silver nanowires generated by the present invention not only have a high aspect ratio, but also have a green and environmentally friendly preparation process and reduce energy consumption.

[0026] 6. A method for preparing silver nanowires based on phenolic compounds and silver nanowires, wherein the second step is to sequentially add polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution into a container, and stir at a stirring rate of 500-1500 rpm to obtain a reaction solution A; the third step is to add the phenolic compound solution as a reducing agent into the reaction solution A to obtain a reaction system B, and stir the reaction system B at a stirring rate of 500-1500 rpm at a temperature of 30°C for 1-3 hours; when used, at a temperature of 30 The reaction system B is stirred and reacted at ℃. The appropriate reaction temperature can avoid side reactions between substances and improve the yield of the chemical reaction. The stirring rate of 500-1500rpm can promote the uniform mixing of the reactants and improve the efficiency and uniformity of the reaction. In the reaction system B, the phenolic compound and the small molecule phenolic acid act as reducing agents to reduce the silver ions into silver atoms to form silver nanowires. The yield of the prepared silver nanowires is more than 70%. The appropriate reaction temperature and stirring speed can increase the aspect ratio of the silver nanowires and improve the yield. Therefore, the present invention not only has a green and environmentally friendly preparation process, but also has a high yield of silver nanowires.

[0027] 7. In a method for preparing silver nanowires based on phenolic compounds and silver nanowires, a high-speed desktop centrifuge is used to centrifuge the mixed solution C containing silver nanowires to obtain a precipitate containing silver nanowires, and then the precipitate containing silver nanowires is washed with deionized water to obtain silver nanowires, and the washing times are at least once; when used, only deionized water is needed to wash the precipitate containing silver nanowires, which is lower in cost and more environmentally friendly than using organic solvents such as acetone or ethanol. At the same time, using deionized water instead of organic solvents for washing operations can avoid chemical changes that may be caused by organic solvents, thereby maintaining the stability of silver nanowires and facilitating long-term storage. Therefore, the present invention not only has a high yield in preparing silver nanowires, but also has a low production cost and good stability of the prepared silver nanowires. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a SEM image of the silver nanowires prepared in Example 10 of the present invention.

[0029] Figure 2 This is a SEM image of the silver nanowires prepared in Example 9 of the present invention.

[0030] Figure 3 This is the SEM image of the silver nanowires prepared in Example 11 of the present invention.

[0031] Figure 4 This is the SEM image of the silver nanowires prepared in Example 12 of the present invention.

[0032] Figure 5 This is the SEM image of the silver nanowires prepared in Example 13 of the present invention.

[0033] Figure 6 This is the SEM image of the silver nanowires prepared in Example 14 of the present invention.

[0034] Figure 7 This is the SEM image of the silver nanowires prepared in Example 15 of the present invention.

[0035] Figure 8 This is the SEM image of the silver nanowires prepared in Example 16 of the present invention.

[0036] Fig. 9 This is the SEM image of the silver nanowires prepared in Example 17 of the present invention.

[0037] Fig.10 This is the XRD pattern of the silver nanowires prepared in Example 9 of the present invention.

[0038] Fig.11 This is the XRD pattern of the silver nanowires prepared in Example 10 of the present invention.

[0039] Fig.12Spectra of silver nanowires prepared in Examples 9-11 of the present invention.

[0040] In the figure: Silver nanowires Ag NWs, silver X-ray diffraction standard card PDF#04-0783. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] See also Figure 1 — Fig.12 , a method for preparing silver nanowires based on phenolic compounds and silver nanowires, the method for preparing silver nanowires comprising the following steps: The first step: using polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound as solutes and deionized water as solvent, first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound in deionized water respectively, and stirring evenly to obtain polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution, and phenolic compound solution; Step 2: first, add the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution prepared in the first step into a container in sequence, and stir at room temperature until the solution turns light yellow, then stop stirring to obtain a reaction solution A; Step 3: first add the phenolic compound solution prepared in the first step to the above reaction solution A to obtain a reaction system B, and stir at room temperature to allow the reaction system B to undergo an oxidation-reduction reaction for 1-3 hours, until the reaction system B changes from light yellow to grayish yellow green and there are obvious layered floccules when shaken, then stop stirring to obtain a mixed solution C containing silver nanowires; Step 4: Centrifuge and wash the mixed solution C containing silver nanowires to obtain silver nanowires.

[0043] In the first step, the silver source is silver nitrate, and the silver source solution is silver nitrate solution; The mass ratio of the polyvinyl pyrrolidone solution, the small molecule phenolic acid solution, the halide solution, the silver nitrate solution and the phenolic compound solution is 50-400: 1.68-34: 0.05-1.35: 0.535-21.6: 0.055-37.8.

[0044] In the first step, the phenolic compound is any one of phloroglucinol, catechol, resorcinol and hydroquinone; When the phenolic compound is phloroglucinol, the concentration of the phenolic compound solution is 0.126 mg / ml-37.8 mg / ml; when the phenolic compound is catechol, resorcinol or hydroquinone, the concentration of the phenolic compound solution is 0.055 mg / ml-33 mg / ml.

[0045] In the first step, the small molecule phenolic acid is gallic acid or caffeic acid; The concentration of the small molecule phenolic acid solution is 1.68 mg / ml-34 mg / ml.

[0046] In the first step, the molecular weight of the polyvinyl pyrrolidone is any one of 10000, 40000, and 800000; The concentration of the polyvinyl pyrrolidone solution is 50 mg / ml-400 mg / ml.

[0047] In the first step, the halide is a compound containing Cl - or Br - Ionic compounds; The concentration of the halide solution is 0.05 mg / ml-1.35 mg / ml.

[0048] In the first step, the molar amount of silver nitrate is 0.05 mmol-0.2 mmol; The concentration of silver ions in the silver nitrate solution is 0.535 mg / ml-21.6 mg / ml.

[0049] In the first step, the step of first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source and phenolic compound in deionized water respectively and stirring them uniformly means: first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide and phenolic compound in deionized water respectively and dissolving them under ultrasound, dissolving the silver source in deionized water and dissolving them at room temperature, and then respectively stirring the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution and phenolic compound solution uniformly; In the second step, the stirring at room temperature refers to: stirring at a stirring rate of 500-1500 rpm, at a temperature of 30° C., for 0-10 minutes; In the third step, stirring at room temperature means: stirring at a stirring rate of 500-1500 rpm, at a temperature of 30° C., for 1-3 hours.

[0050] In the fourth step, the step of centrifuging and washing the mixed solution C containing silver nanowires in sequence to obtain silver nanowires means: centrifuging the mixed solution C containing silver nanowires using a high-speed desktop centrifuge to obtain a precipitate containing silver nanowires, and then washing the precipitate containing silver nanowires with deionized water to obtain silver nanowires, the washing number of times being at least once; and then ultrasonically dispersing the silver nanowires to obtain uniformly dispersed silver nanowires.

[0051] The silver nanowires are made by the method for preparing silver nanowires based on phenolic compounds as described in any one of claims 1 to 7; The silver nanowire has a diameter of 20-150 nm and a length of 5-100 μm.

[0052] The supplementary description of the present invention is as follows: In the present invention, in the first step, the halide is preferably any one of CuCl2, KCl, MgCl2, KBr, and CuBr2.

[0053] In the present invention, the silver source used in the first step is preferably silver nitrate, which is in granular form and has analytical purity.

[0054] In the preferred first step of the present invention, the silver source solution may also be a silver halide solution or a silver ammonia solution.

[0055] The present invention preferably uses silver nitrate as the silver source for better results.

[0056] In the present invention, preferably, in the second step, the container is a reaction bottle.

[0057] In the present invention, preferably, the stirring time in the second step is 5 minutes.

[0058] In the third step of the present invention, a redox reaction occurs in the reaction system B, and the small molecule phenolic acid + phenolic compound + Ag + →Quinone compounds+Ag 0 .

[0059] In the present invention, the stirring time in the third step is preferably determined according to the amount of the reducing agent small molecule phenolic acid and phenolic compound added; the more the reducing agent is added, the shorter the stirring time is, and the less the reducing agent is added, the longer the stirring time is.

[0060] In the preferred fourth step of the present invention, the rotation speed of the high-speed desktop centrifuge is 6500 rpm and the centrifugation time is 3 min.

[0061] In the fourth step of the present invention, the precipitate containing the silver nanowires is preferably washed and then dispersed using ultrasound to obtain uniformly dispersed silver nanowires, and finally the silver nanowires are directly stored in deionized water.

[0062] In the present invention, the stirring rates in the second step and the third step are preferably both 1000 rpm.

[0063] In the present invention, the stirring is preferably carried out in a water bath.

[0064] The present invention preferably uses a pipette to take the required amount of solution and add it to the reaction solution respectively.

[0065] The present invention prefers silver nanowires with a higher aspect ratio because of their better conductivity, mechanical properties and surface area.

[0066] The preferred silver nanowires of the present invention have good size uniformity, which is the key to ensuring stable and controllable material performance, especially in applications requiring precise performance and high reliability.

[0067] The present invention preferably uses silver nanowires with higher aspect ratio and better size uniformity to produce products with high optical transparency, low haze and low resistance (Rs), wherein the silver nanowires with high aspect ratio and better size uniformity are closely arranged in the film to reduce light scattering, improve light transmittance, and make the product have high optical transparency; the uniform size and spacing reduce light scattering and reduce the haze of the product; the high aspect ratio and uniform size ensure a better conductive path, reduce obstacles in electron transmission, and reduce the resistance of the product.

[0068] The preferred reducing agent of the present invention is any combination of small molecule phenolic acids (gallic acid, caffeic acid) and phenolic compounds (phloroglucinol, catechol, resorcinol, hydroquinone).

[0069] The reason why the reducing agents of the present invention are preferably small molecule phenolic acids and phenolic compounds is that the reaction rate is significantly improved without affecting the growth of silver nanowires. When the reducing agent is small, silver nanowires can basically grow after two hours of reaction. When the reducing agent is large, it only takes 30 minutes to 60 minutes to grow silver nanowires. In addition, when different phenolic compounds and small molecule phenolic acids act, the lengths of the grown silver nanowires will also be different. The aspect ratio of the silver nanowires can be indirectly adjusted by adjusting the content of the two reducing agents.

[0070] Embodiment 1: See also Figure 1 — Fig.12 , a method for preparing silver nanowires based on phenolic compounds and silver nanowires, the method for preparing silver nanowires comprising the following steps: The first step: using polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound as solutes and deionized water as solvent, first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound in deionized water respectively, and stirring evenly to obtain polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution, and phenolic compound solution; Step 2: first, add the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution prepared in the first step into a container in sequence, and stir at room temperature until the solution turns light yellow, then stop stirring to obtain a reaction solution A; Step 3: first add the phenolic compound solution prepared in the first step to the above reaction solution A to obtain a reaction system B, and stir at room temperature to allow the reaction system B to undergo an oxidation-reduction reaction for 1-3 hours, until the reaction system B changes from light yellow to grayish yellow green and there are obvious layered floccules when shaken, then stop stirring to obtain a mixed solution C containing silver nanowires; Step 4: Centrifuge and wash the mixed solution C containing silver nanowires to obtain silver nanowires.

[0071] When applied, the growth process of silver nanowires is a complex chemical and physical process, which usually involves the introduction of halogens, the reduction of silver ions, the formation of quintuple twins, and the role of surface protectants. The right amount of halogens helps to fix silver atoms. The right amount of polyvinyl pyrrolidone is also crucial to the growth of silver nanowires, which affects the growth direction of silver atoms and the shape of silver nanowires. Each step in this growth process needs to be strictly controlled to ensure the generation of high-quality, high-aspect-ratio silver nanowires. See also Figure 1-Figure 9 The morphology and distribution characteristics of silver nanowires are shown using scanning electron microscope (SEM) images. It can be seen that the silver nanowires prepared by the present invention have fewer particles, are more evenly distributed, and have uniform sizes. See also Figure 10-11 The X-ray diffraction (XRD) pattern of silver nanowires was used to analyze the crystal structure characteristics of silver nanowires: the diffraction peaks of silver nanowires matched the peak positions on the PDF#04-0783 standard card, which indicated that Fig.10 and Fig.11 The silver nanowires in have a face-centered cubic (FCC) crystal structure, and the main diffraction peaks appear at the following angles (2θ): (111) plane at about 38.1°, (200) plane at about 44.3°, (220) plane at about 64.5°, and (311) plane at about 77.4°; Fig.10 The diffraction peak intensity of the (111) plane is the highest, indicating Fig.10 The silver nanowires have a strong (111) orientation. Fig.11 The diffraction peak intensity of the (200) plane is the highest, indicating that Fig.11 Silver nanowires have a strong (200) plane orientation. The crystal orientation of silver nanowires affects the optical properties, electrical properties and interactions with other materials. Silver nanowires with a (111) plane orientation will exhibit better optical transparency and conductivity because the (111) plane is the plane with the closest atomic arrangement in the face-centered cubic structure, which helps to improve the conductivity; while silver nanowires with a (200) plane orientation exhibit better chemical stability and have specific optical absorption and scattering properties.

[0072] Embodiment 2: The basic content is the same as Example 1, except that: in the first step, the silver source is silver nitrate, and the silver source solution is a silver nitrate solution; the mass ratio of the polyvinyl pyrrolidone solution, the small molecule phenolic acid solution, the halide solution, the silver nitrate solution, and the phenolic compound solution is 50-400: 1.68-34: 0.05-1.35: 0.535-21.6: 0.055-37.8.

[0073] When used, silver nitrate is used as a silver source to provide silver ions for reaction. These silver ions are the basic raw materials for synthesizing silver nanowires. The more silver ions are used, the better. However, excessive use of silver nitrate may lead to insufficient use of other components, resulting in uneven distribution of silver nanowires and more particles. At the same time, considering resource costs and economic costs, a suitable amount can be selected; small molecule phenolic acids and phenolic compounds are used as reducing agents. Excessive use will lead to accelerated reaction speed and generate silver nanoparticles with smaller particle size and irregular morphology. Excessive use will slow down the reaction speed and generate silver nanowires with larger particle size and uneven growth, and lead to incomplete reaction of silver ions. Thereby affecting the morphology and size of the silver nanowires; the dosage of the surface protective agent polyvinyl pyrrolidone (PVP) is also crucial to the growth of silver nanowires. It affects the growth direction of silver atoms and the shape of the silver nanowires. Too little dosage will cause the grown silver nanowires to be relatively short and uneven. As the dosage of PVP increases, the silver nanowires become slender and uniform. When the dosage of polyvinyl pyrrolidone reaches 300 mg or more, the morphology of the silver nanowires does not change significantly, but it will lead to more centrifugation and washing times in subsequent processing; too little halide will cause the generated silver nanowires to be relatively curved, short and unevenly distributed, while too much halide will cause the silver nanowires to become thicker.

[0074] Embodiment 3: The basic content is the same as Example 1, except that: in the first step, the phenolic compound is any one of phloroglucinol, catechol, resorcinol and hydroquinone; when the phenolic compound is phloroglucinol, the concentration of the phenolic compound solution is 0.126 mg / ml-37.8 mg / ml, and when the phenolic compound is catechol, resorcinol or hydroquinone, the concentration of the phenolic compound solution is 0.055 mg / ml-33 mg / ml; in the first step, the small molecule phenolic acid is gallic acid or caffeic acid; the concentration of the small molecule phenolic acid solution is 1.68 mg / ml-34 mg / ml.

[0075] When used, small molecule phenolic acid and phenolic compounds act as reducing agents to jointly reduce silver ions to silver atoms; phenolic compounds act as reducing agents, and their reducing properties are stronger than traditional alcohol reducing agents, and effective reduction reactions can be carried out at lower temperatures; small molecule phenolic acids belong to plant polyphenols, which are not only widely available, but also green and non-toxic. They replace traditional harmful chemicals in the synthesis process, making the entire preparation process more environmentally friendly and sustainable; moreover, the presence of phenolic acid molecules promotes the transfer of electrons from phenolic compounds to silver ions, making the reduction of silver ions more efficient. Generally, phenolic compounds have strong reducing ability, while small molecule phenolic acids regulate this process through their electron-withdrawing effect. Therefore, by adjusting the concentration or content ratio of small molecule phenolic acids and phenolic compounds, the reduction rate of silver ions can be precisely controlled. This regulation helps to finely adjust the growth process of silver nanowires, thereby affecting the morphology of silver nanowires, especially their aspect ratio, so that the aspect ratio of silver nanowires can be controlled.

[0076] Embodiment 4: The basic contents are the same as those of Example 1, except that: in the first step, the molecular weight of the polyvinyl pyrrolidone is any one of 10,000, 40,000, and 800,000; and the concentration of the polyvinyl pyrrolidone solution is 50 mg / ml-400 mg / ml.

[0077] When used, polyvinyl pyrrolidone (PVP) can not only prevent the aggregation and sedimentation of nanoparticles, but also affect the growth and morphology of nanoparticles, thereby affecting the shape and size of nanowires; higher PVP molecular weight and appropriate concentration can promote the slenderness and uniform growth of silver nanowires. As the amount of PVP increases, the silver nanowires become slender and uniform. When the amount of polyvinyl pyrrolidone reaches 300 mg or more, there is little change, so 300 mg is selected as the optimal value.

[0078] Embodiment 5: The basic content is the same as Example 1, except that: in the first step, the halide is a compound containing Cl - or Br -ionic compound; the concentration of the halide solution is 0.05 mg / ml-1.35 mg / ml.

[0079] When applied, the presence of halogen in the halide has a dual effect on the growth of silver nanowires: in the early stage of the growth process, halogen ions (such as chloride ions) and silver ions form insoluble tiny particles, which play a role in fixing silver atoms and reducing the concentration of free silver ions in the initial stage of the reaction; in the later stage of the growth process, halogen ions (such as chloride ions) can play a traction role, so an appropriate amount of halogen helps to fix silver atoms, but excessive halogen may cause structural changes in silver nanowires; using halides containing Cl - or Br - Compounds containing Br - When the silver nanowires are made of halides containing Cl (such as CuBr2, KBr, and NaBr), the resulting silver nanowires are thicker and shorter, and the effect is not good. - When the halides of ions are present (such as CuCl2, KCl, NaCl), the generated silver nanowires are relatively slender, among which CuCl2 has the best effect; the halide is any one of CuCl2, KCl, MgCl2, and NaCl.

[0080] Embodiment 6: The basic content is the same as Example 1, except that: in the first step, the polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound are respectively dissolved in deionized water, and stirred evenly, which means: first, polyvinyl pyrrolidone, small molecule phenolic acid, halide, and phenolic compound are respectively dissolved in deionized water and dissolved under ultrasound, and the silver source is dissolved in deionized water and dissolved at room temperature, and then the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution, and phenolic compound solution are respectively stirred evenly; in the second step, stirring at room temperature means: using a stirring rate of 500-1500 rpm, stirring at a temperature of 30° C. for 0-10 minutes; in the third step, stirring at room temperature means: using a stirring rate of 500-1500 rpm, stirring at a temperature of 30° C. for 1-3 hours.

[0081] When used, in the second step, the corresponding solutions are added to the reaction bottle respectively, and stirred at a stirring rate of 500-1500rpm, preferably 1000rpm, to stir the reaction solution A evenly to ensure that the components are evenly dispersed in the container; in the third step, a required amount of phenol compound solution is taken by a pipette and added to the reaction solution A to form a reaction system B, and stirred in a water bath at 30°C at a stirring rate of 500-1500rpm, preferably 1000rpm, for 1-3 hours to ensure that the reaction is sufficient and uniform; the reaction system B is stirred at a uniform speed to make the ions in the reaction system fully contact and evenly dispersed, which is conducive to the directional growth of silver nanowires. At the same time, a suitable stirring rate is also conducive to the generation of silver nanowires. When the stirring rate is too slow, the silver atoms will be unevenly dispersed in the solution, the reaction rate will be slow, and more particles will be formed. When the stirring rate is too fast, the halogen ions (such as chloride ions) and the silver ions will directly form insoluble silver halide precipitates (such as AgCl).

[0082] Embodiment 7: The basic content is the same as Example 1, except that: in the fourth step, the obtaining of silver nanowires after centrifuging and washing the mixed solution C containing silver nanowires in sequence means: centrifuging the mixed solution C containing silver nanowires with a high-speed desktop centrifuge to obtain a precipitate containing silver nanowires, and then washing the precipitate containing silver nanowires with deionized water to obtain silver nanowires, the washing number of times is at least once; and then ultrasonically dispersing the silver nanowires to obtain uniformly dispersed silver nanowires.

[0083] During application, a high-speed desktop centrifuge is used to centrifuge a mixed solution C containing silver nanowires, and after centrifugation, the supernatant is aspirated to obtain a precipitate containing silver nanowires. The precipitate containing silver nanowires is washed with deionized water to remove residual ions after the reaction, unreacted precursors and possible impurities. After washing twice, the obtained silver nanowires are dispersed by ultrasonic dispersion to prevent the silver nanowires from forming aggregates, thereby obtaining uniformly dispersed silver nanowires, and the silver nanowires are directly stored in deionized water, which is conducive to long-term storage and subsequent applications. Using deionized water to wash and store the silver nanowires can replace organic solvents, which is lower in cost and more environmentally friendly, and can avoid chemical changes that may be caused by organic solvents, thereby maintaining the stability of the silver nanowires.

[0084] Embodiment 8: The basic content is the same as that of Example 1, except that: The first step: firstly dissolve polyvinyl pyrrolidone, small molecule phenolic acid, chloride, silver nitrate and phenolic compound in deionized water respectively, and then stir evenly to obtain polyvinyl pyrrolidone solution, small molecule phenolic acid solution, chloride solution, silver nitrate solution and phenolic compound solution; wherein the small molecule phenolic acid is gallic acid or caffeic acid, the chloride is any one of CuCl2, KCl, MgCl2 and NaCl, and the molar amount of the silver ion is 0.2mmol; the molecular weight of the polyvinyl pyrrolidone is any one of 10000, 40000 and 80000, and the mass of the polyvinyl pyrrolidone is 300mg; the reducing agent phenolic compound is any one of phloroglucinol, catechol, resorcinol and hydroquinone; Step 2: first, add the above-mentioned polyvinyl pyrrolidone solution, small molecule phenolic acid solution, chloride solution and silver nitrate solution in a container in order according to the required proportions, and stir for 5 minutes to obtain a reaction solution A; the molar ratio of the silver nitrate to the chloride is 200:3; Step 3: first, add the phenolic compound solution prepared in the first step into the above reaction solution A in a desired proportion to obtain a reaction system B, stir the reaction system B at 30° C. for 1-3 hours to obtain a mixed solution C containing silver nanowires; Step 4: Centrifuge and wash the mixed solution C containing silver nanowires to obtain silver nanowires.

[0085] Embodiment 9: The basic contents are the same as those of Example 8, except that: The first step: firstly dissolve polyvinyl pyrrolidone, gallic acid, CuCl2, silver nitrate and hydroquinone in deionized water respectively, and then stir evenly to obtain polyvinyl pyrrolidone solution, gallic acid solution, CuCl2 solution, silver nitrate solution and hydroquinone solution; Step 2: first, sequentially add the above-mentioned polyvinyl pyrrolidone solution, gallic acid solution, CuCl2 solution, and silver nitrate solution into a container, and stir for 5 minutes to obtain a reaction solution A; the molar ratio of the silver nitrate to CuCl2 is 200:3, and the mass ratio of the polyvinyl pyrrolidone to gallic acid and silver ions is 88:1:10; Step 3: first add the hydroquinone solution prepared in the first step to the above reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to hydroquinone is 200:0.5-20, and stir the reaction system B at 30° C. for 1-3 hours to obtain a mixed solution C containing silver nanowires; Step 4: Centrifuge and wash the mixed solution C containing silver nanowires to obtain silver nanowires; See also Figure 2 and Fig.10The average diameter of the silver nanowires is 30-50 nm and the average length is 50-70 μm.

[0086] Embodiment 10: The basic contents are the same as those of Example 9, except that: In the first step, the small molecule phenolic acid used was caffeic acid and the chloride was KCl; See also Figure 1 and Fig.11 The average diameter of the silver nanowires is 20-100 nm, and the average length is 90-120 μm. Compared with Example 9, the silver nanowires prepared in Example 10 are longer and more uniform in size.

[0087] Embodiment 11: The basic contents are the same as those of Example 9, except that: In the first step, the small molecule phenolic acid used was caffeic acid and the chloride was KCl; In the third step, the molar ratio of silver ions to hydroquinone is 200:30-250; See also Figure 3 The average diameter of the silver nanowires is 20-50 nm and the average length is 30-50 μm. Compared with Example 10, the amount of the reducing agent phenolic compound is mainly increased, so that the reaction rate is accelerated and the reaction time is significantly shortened. The average length of the silver nanowires prepared in Example 11 is shortened, and the aspect ratio of the silver nanowires changes.

[0088] Embodiment 12: The basic contents are the same as those of Example 9, except that: In the first step, the phenolic compound used was phloroglucinol; In the third step, the phloroglucinol solution prepared in the first step is first added to the above reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to phloroglucinol is 200:30-250, and the mixture is stirred at 30° C. for 3 hours to obtain a mixed solution C; See also Figure 4 The average diameter of the silver nanowires is 20-50 nm and the average length is 30-60 μm.

[0089] Embodiment 13: The basic contents are the same as those of Example 9, except that: In the first step, the small molecule phenolic acid used is caffeic acid, the chloride is KCl, and the phenolic compound is phloroglucinol; In the third step, the phloroglucinol solution prepared in the first step is first added to the reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to phloroglucinol is 200:30-250, and the mixture is stirred at 30° C. for 1.5 hours to obtain a mixed solution C; See also Figure 5 The average diameter of the silver nanowires is 30-50 nm and the average length is 40-60 μm.

[0090] Embodiment 14: The basic contents are the same as those of Example 9, except that: In the second step, the molar ratio of silver ions to small molecular phenolic acid is 10:2-7; In the third step, the hydroquinone solution prepared in the first step is first added to the reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to hydroquinone is 10:1, and the mixture is stirred at 30° C. for 1.5 hours to obtain a mixed solution C; See also Figure 6 The average diameter of the silver nanowires is 50-80 nm and the average length is 30-50 μm.

[0091] Embodiment 15: The basic contents are the same as those of Example 9, except that: In the first step, the small molecule phenolic acid used was caffeic acid and the chloride was KCl; In the second step, the molar ratio of silver ions to caffeic acid is 10:2-7; In the third step, the hydroquinone solution prepared in the first step is first added to the reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to hydroquinone is 5:2, and the mixture is stirred at 30° C. for 1 hour to obtain a mixed solution C; See also Figure 7 The average diameter of the silver nanowires is 80-100 nm and the average length is 10-30 μm. Compared with Example 14, the amount of the reducing agent hydroquinone used in Example 15 is increased and fixed, so that the aspect ratio of the silver nanowires obtained in Example 15 is changed relative to that in Example 14.

[0092] Embodiment 16: The basic contents are the same as those of Example 9, except that: In the first step, the chloride used is KCl and the phenolic compound is catechol; In the second step, the molar ratio of silver ions to gallic acid was 10:1; In the third step, the catechol solution prepared in the first step is first added to the reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to catechol is 10:1-20, and the mixture is stirred at 30° C. for 2 hours to obtain a mixed solution C; See also Figure 8 The average diameter of the silver nanowires is 100-150 nm and the average length is 5-10 μm.

[0093] Embodiment 17: The basic contents are the same as those of Example 9, except that: In the first step, the chloride used is KCl and the phenolic compound is resorcinol; In the second step, the polyvinyl pyrrolidone solution, resorcinol solution, gallic acid solution and KCl solution are sequentially added into a container and stirred for 5 minutes to obtain a reaction solution A; In the third step, the silver nitrate solution prepared in the first step is first added to the reaction solution A to obtain a reaction system B, wherein the molar ratio of silver ions to gallic acid is 4:1, and the molar ratio of silver ions to resorcinol is 4:1, and the mixture is stirred at 30° C. for 2 hours to obtain a mixed solution C; See also Fig. 9 The average diameter of the silver nanowires is 20-50 nm and the average length is 10-60 μm.

[0094] Embodiment 18: The basic content is the same as Example 1, except that: Fig.12, the UV-visible spectra of silver nanowires (AgNWs) were tested for Examples 9 to 11. In the figure, AgNWs-1, AgNWs-2, and AgNWs-3 are silver nanowires prepared in Examples 9, 10, and 11, respectively; the shape and growth state of AgNWs can be reflected by the UV-visible spectra. As shown in the figure, the UV spectra of AgNWs-1, AgNWs-2, and AgNWs-3 are relatively smooth and free of impurity peaks, indicating that under such conditions, the prepared AgNWs are uniform and pure, of good quality, and no other substances are produced; wherein For AgNWs-1: the peak at 349nm corresponds to the longitudinal resonance peak of the pentagonal twin crystal seeds of one-dimensional AgNWs, and the peak at 375nm is the transverse characteristic peak of nanosilver, which confirms the one-dimensional growth of silver and thus the formation of silver nanowires; the UV-visible spectrum of the silver nanowires proves that the present invention successfully synthesized AgNWs with a relatively high aspect ratio; in order to verify the purity of the silver nanowires, the silver nanowires with higher purity will show obvious and sharp absorption peaks, while samples containing more impurities (such as unreduced silver ions, silver nanoparticles, etc.) generally show multiple absorption peaks at different wavelengths. According to the intensity and morphology of the absorption peak, the purity can be inferred by quantitative methods, specifically by comparing with standard samples or using standard curves to quantitatively analyze the concentration and purity of the silver nanowires. According to this method and Fig.12 It can be seen that the purity of the silver nanowires produced in this design is 98% to 99.5%.

[0095] Embodiment 19: See also Figure 1-Figure 9 In combination with Examples 9 to 17, it can be found that when small molecule phenolic acid is combined with hydroquinone or phloroglucinol, it is more conducive to growing silver nanowires with a high aspect ratio; the more polyvinyl pyrrolidone, the more conducive to growing silver nanowires with a high aspect ratio; when the small molecule phenolic acid is a combination of caffeic acid and hydroquinone, the grown silver nanowires are all shorter; the length of the silver nanowires is significantly affected by the amount of small molecule phenolic acid, and the more the amount of small molecule phenolic acid, the shorter and thicker the generated silver nanowires. Although increasing the amount of phenolic compounds will also affect the length of the silver nanowires, the effect is not as obvious as changing the amount of small molecule phenolic acids; increasing the amount of reducing agent (small molecule phenolic acid and phenolic compounds) will increase the reaction rate and easily generate short and thick silver nanowires.

[0096] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed by the present invention should be included in the protection scope recorded in the claims.

Claims

1. A method for preparing silver nanowires based on phenolic compounds, characterized in that: The method for preparing the silver nanowires comprises the following steps: The first step: using polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound as solutes and deionized water as solvent, first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source, and phenolic compound in deionized water respectively, and stirring evenly to obtain polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution, and phenolic compound solution; Step 2: first, add the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution and silver source solution prepared in the first step into a container in sequence, and stir at room temperature until the solution turns light yellow, then stop stirring to obtain a reaction solution A; Step 3: first add the phenolic compound solution prepared in the first step to the above reaction solution A to obtain a reaction system B, and stir at room temperature to allow the reaction system B to undergo an oxidation-reduction reaction for 1-3 hours, until the reaction system B changes from light yellow to grayish yellow green and there are obvious layered floccules when shaken, then stop stirring to obtain a mixed solution C containing silver nanowires; Step 4: Centrifuge and wash the mixed solution C containing silver nanowires to obtain silver nanowires.

2. The method for preparing silver nanowires based on phenolic compounds according to claim 1, characterized in that: In the first step, the silver source is silver nitrate, and the silver source solution is silver nitrate solution; The mass ratio of the polyvinyl pyrrolidone solution, the small molecule phenolic acid solution, the halide solution, the silver nitrate solution and the phenolic compound solution is 50-400: 1.68-34: 0.05-1.35: 0.535-21.6: 0.055-37.

8.

3. The method for preparing silver nanowires based on phenolic compounds according to claim 2, characterized in that: In the first step, the phenolic compound is any one of phloroglucinol, catechol, resorcinol and hydroquinone; When the phenolic compound is phloroglucinol, the concentration of the phenolic compound solution is 0.126 mg / ml-37.8 mg / ml; when the phenolic compound is catechol, resorcinol or hydroquinone, the concentration of the phenolic compound solution is 0.055 mg / ml-33 mg / ml.

4. The method for preparing silver nanowires based on phenolic compounds according to claim 2, characterized in that: In the first step, the small molecule phenolic acid is gallic acid or caffeic acid; The concentration of the small molecule phenolic acid solution is 1.68 mg / ml-34 mg / ml.

5. The method for preparing silver nanowires based on phenolic compounds according to claim 2, characterized in that: In the first step, the molecular weight of the polyvinyl pyrrolidone is any one of 10000, 40000, and 800000; The concentration of the polyvinyl pyrrolidone solution is 50 mg / ml-400 mg / ml.

6. The method for preparing silver nanowires based on phenolic compounds according to claim 2, characterized in that: In the first step, the halide is a compound containing Cl - or Br - Ionic compounds; The concentration of the halide solution is 0.05 mg / ml-1.35 mg / ml.

7. The method for preparing silver nanowires based on phenolic compounds according to claim 2, characterized in that: In the first step, the molar amount of silver nitrate is 0.05 mmol-0.2 mmol; The concentration of silver ions in the silver nitrate solution is 0.535 mg / ml-21.6 mg / ml.

8. A method for preparing silver nanowires based on phenolic compounds according to any one of claims 1 to 7, characterized in that: In the first step, the step of first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide, silver source and phenolic compound in deionized water respectively and stirring them uniformly means: first dissolving polyvinyl pyrrolidone, small molecule phenolic acid, halide and phenolic compound in deionized water respectively and dissolving them under ultrasound, dissolving the silver source in deionized water and dissolving them at room temperature, and then respectively stirring the polyvinyl pyrrolidone solution, small molecule phenolic acid solution, halide solution, silver source solution and phenolic compound solution uniformly; In the second step, the stirring at room temperature refers to: stirring at a stirring rate of 500-1500 rpm, at a temperature of 30° C., for 0-10 minutes; In the third step, stirring at room temperature means: stirring at a stirring rate of 500-1500 rpm, at a temperature of 30° C., for 1-3 hours.

9. A method for preparing silver nanowires based on phenolic compounds according to any one of claims 1 to 7, characterized in that: In the fourth step, the step of centrifuging and washing the mixed solution C containing silver nanowires in sequence to obtain silver nanowires means: centrifuging the mixed solution C containing silver nanowires using a high-speed desktop centrifuge to obtain a precipitate containing silver nanowires, and then washing the precipitate containing silver nanowires with deionized water to obtain silver nanowires, the washing number of times being at least once; and then ultrasonically dispersing the silver nanowires to obtain uniformly dispersed silver nanowires.

10. A silver nanowire, characterized in that: The silver nanowires are made by the method for preparing silver nanowires based on phenolic compounds as described in any one of claims 1 to 7; The silver nanowire has a diameter of 20-150 nm and a length of 5-100 μm.

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