Conductive Material, Conductive Thin Film and Preparation Method Thereof

Abstract

This application discloses a conductive material and conductive film, and methods for preparing the same. The conductive material comprises copper nanowires, a coating, and a conductive polymer. The coating is coated on the surface of the copper nanowires to form a copper nanowire core-shell structure material with the copper nanowires as the core and the coating as the shell, wherein the coating comprises a metal or metal oxide. The conductive polymer and the copper nanowire core-shell structure material form a copolymer. Based on the preparation of the copper nanowire core-shell structure material, this application utilizes a silane coupling agent to graft the conductive polymer. This method has the advantages of a simple preparation and synthesis method, low cost, low temperature, and environmental safety. The resulting conductive film exhibits excellent conductivity and light transmittance, and has broad application prospects.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a conductive material and a conductive film and a preparation method thereof. Background Art

[0002] Transparent electrodes (TEs) play a crucial role in the development of the electronics and optoelectronics industries. They are essential optoelectronic functional materials for the fabrication of numerous electronic and optoelectronic components, primarily used in touch screens, solar cells, flat-panel displays, light-emitting diodes, and sensors. With the advancement of flexible, wearable, and portable electronic technologies, transparent electrodes are facing higher demands. They must not only possess excellent optoelectronic properties and superior chemical stability, but also be highly flexible and capable of being fabricated on a large scale at low cost. Limited by the high price and low utilization rate of indium tin oxide (ITO), various materials have been explored as alternatives to ITO, including carbon nanotubes, graphene, metal meshes, and metal nanowires. While carbon nanotubes offer high mechanical strength, their industrial mass production technology is not yet mature, and the resulting films exhibit poor conductivity. Graphene transparent electrodes have performance close to that of ITO, but the complex film-forming process results in low yields and high manufacturing costs. Metal meshes offer excellent performance, but their regular structure is prone to Murray interference. Metal nanowire transparent electrodes, with their high flexibility, excellent light transmittance, and electrical conductivity, are promising alternatives to ITO. Currently, transparent electrodes made from silver nanowires (Ag Nanowires, AgNWs) outperform ITO, but AgNWs are still expensive. Copper has comparable electrical conductivity to silver, but costs only 1% of silver and is abundant. Therefore, transparent electrodes made from copper nanowires (CuNWs) hold promise for broader applications and greater market competitiveness.

[0003] CuNWs, as transparent conductive layers, have attracted widespread attention from researchers and industry due to their excellent optical transmittance, conductivity, flexibility, and low cost. Currently, the commercial production of CuNWs has been achieved: transparent electrodes fabricated using CuNWs achieve a sheet resistance of 28–40 Ω / sq at 90% transmittance, comparable to that of ITO. CuNWs transparent electrodes offer excellent performance and promising applications, but their susceptibility to oxidation limits their application in optoelectronic devices. Exposed to air, CuNWs readily react with water and oxygen in the air, spontaneously forming an oxide layer on their surface, rendering them ineffective. Therefore, achieving flexible transparent electrodes with lower sheet resistance and higher transmittance, while also ensuring that CuNWs resist oxidation, has become a hot topic and a challenge in this field. Currently, researchers are widely using CuNWs composite thin films to improve their stability. While this approach effectively improves the stability of CuNWs, it sacrifices some conductivity and transmittance. Therefore, it is necessary to design and prepare a CuNWs composite film with high conductivity, high transmittance and excellent air stability. Summary of the Invention

[0004] The present application provides a conductive material and a conductive film and a preparation method thereof, which have high light transmittance and conductivity and high stability.

[0005] The present application provides a conductive material, which includes copper nanowires, a coating layer and a conductive polymer; the coating layer is coated on the surface of the copper nanowire to form a copper nanowire core-shell structure material with the copper nanowire as the core and the coating layer as the shell, and the coating layer includes a metal or a metal oxide; the conductive polymer and the copper nanowire core-shell structure material form a copolymer.

[0006] Optionally, in some embodiments of the present application, the conductive polymer is polymerized with the copper nanowire core-shell structure via free radicals.

[0007] Optionally, in some embodiments of the present application, the diameter of the copper nanowire is 50-200 nm.

[0008] Optionally, in some embodiments of the present application, the coating layer includes one or more of silver, zinc, tin, nickel, titanium, silver oxide, zinc oxide, tin oxide, nickel oxide or titanium dioxide.

[0009] Optionally, in some embodiments of the present application, the conductive polymer includes one or more of polyethylenedioxythiophene, polypyrrole, polythiophene, polyphenylene, polyphenylene vinylene or polyaniline.

[0010] Optionally, in some embodiments of the present application, the ratio of the copper nanowires, the coating layer, and the conductive polymer is 1:1-1.5:10-1000.

[0011] Optionally, in some embodiments of the present application, the molecular weight of the conductive polymer is 10,000 to 100,000.

[0012] The present application also provides a method for preparing a conductive material, comprising: mixing an inorganic copper salt precursor, a reducing agent, and a dispersant in an alkaline solution, heating the mixture to react and obtain copper nanowires; adding a weak acid and polyvinyl pyrrolidone to the copper nanowires, adding a metal salt and an ion control agent after mixing, reacting, and centrifuging to obtain a copper nanowire core-shell structure material; modifying the copper nanowire core-shell structure material with an acid, and adding a conductive polymer under the action of a silane coupling agent to obtain a conductive material.

[0013] Optionally, in some embodiments of the present application, the inorganic copper salt precursor includes one or more of copper nitrate, copper chloride dihydrate, copper chloride or copper bromide.

[0014] Optionally, in some embodiments of the present application, the reducing agent includes one or more of glucose, sodium citrate, ascorbic acid or borohydride.

[0015] Optionally, in some embodiments of the present application, the dispersant includes one or more of polyvinylpyrrolidone, oleylamine or octadecylamine.

[0016] Optionally, in some embodiments of the present application, the alkaline solution includes one or more of ammonia water, sodium hydroxide solution or potassium hydroxide solution.

[0017] Optionally, in some embodiments of the present application, the metal salt includes one or more of silver nitrate, zinc chloride, tin chloride, nickel acetylacetonate, titanium acetylacetonate or silver acetylacetonate.

[0018] Optionally, in some embodiments of the present application, the ion control agent includes one or more of sodium chloride, potassium chloride, sodium bromide or potassium bromide.

[0019] Optionally, in some embodiments of the present application, the acid includes one or more of hydrochloric acid, nitric acid or sulfuric acid.

[0020] Optionally, in some embodiments of the present application, the silane coupling agent includes one or more of vinyltriethoxysilane, vinyltrimethoxysilane or vinyltrimethoxyethoxysilane.

[0021] Optionally, in some embodiments of the present application, the conductive polymer includes one or more of polyethylenedioxythiophene, polypyrrole, polythiophene, polyphenylene, polyphenylene vinylene or polyaniline.

[0022] Optionally, in some embodiments of the present application, the temperature of the heating reaction is 100-200°C.

[0023] Optionally, in some embodiments of the present application, the heating reaction time is 4 to 6 hours.

[0024] Optionally, in some embodiments of the present application, the concentration of the inorganic copper salt precursor is 2.0-6.0 g / L.

[0025] The present application also provides a conductive film, which includes the above-mentioned conductive material or the conductive material prepared by the above-mentioned preparation method.

[0026] Optionally, in some embodiments of the present application, the light transmittance of the conductive film may be 80% to 93%, or 83% to 90%, or 85% to 88%.

[0027] Optionally, in some embodiments of the present application, the square resistance of the conductive film may be 10 to 40 Ω / sq, or 15 to 35 Ω / sq, or 20 to 30 Ω / sq.

[0028] The conductive material provided in this application has the following beneficial effects:

[0029] (1) The conductive material of the present application is coated with a metal or metal oxide coating layer, which improves the stability of the conductive material. At the same time, the conductive material of the present application is grafted with a conductive polymer and has excellent light transmittance and conductivity;

[0030] (2) Conductive materials are prepared by liquid phase synthesis, and a preparation process is formed under low cost and low temperature (<200°C) conditions that can mass-produce transparent conductive films with excellent photoelectric properties and high stability, giving them broader application prospects and benefits. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0032] The present application provides a conductive material and a conductive film and a method for preparing the same. These are described in detail below. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments.

[0033] An embodiment of the present application provides a conductive material, which includes copper nanowires, a coating layer and a conductive polymer; the coating layer is coated on the surface of the copper nanowire to form a copper nanowire core-shell structure material with the copper nanowire as the core and the coating layer as the shell, and the coating layer includes a metal or a metal oxide; the conductive polymer and the copper nanowire core-shell structure material form a copolymer.

[0034] To mitigate the susceptibility of CuNWs to oxidation, researchers typically employ coating methods, adding a protective layer to the surface of CuNWs to enhance their stability. Common coating methods include chemical vapor deposition (CVD) graphene coating, graphene oxide coating, nickel or silver metal coating, oxide coating, and polymer coating. Graphene exhibits excellent conductivity and chemical stability. Coating CuNWs with a graphene layer effectively protects them from oxidation and environmental corrosion. Transparent CuNW composite electrodes coated with graphene were fabricated using CVD at 400°C. The composite electrodes exhibit excellent oxidation resistance and stability, with a floor resistance of 23.2 Ω / sq at a transmittance of 83.4%. However, due to the high preparation temperature, these films are not suitable for flexible substrates. Graphene oxide (GO) is amenable to liquid-phase film formation methods such as vacuum filtration, spin coating, and spray coating, and can be fabricated continuously over large areas. Ultrasonic technology was used to tightly wrap GO nanosheets around ultrafine CuNWs, and then GO was reduced by annealing at 260°C for 30 minutes in a 10% H2 atmosphere. The photoelectric performance of the CuNW-rGO composite transparent electrode was found to be: the film had a square resistance of 28.2Ω / sq at a transmittance of 89.2%, but since the preparation process required high temperature and hydrogen or helium protection, there were disadvantages in safety and preparation price; nickel (Ni) has good mechanical strength and ductility, high temperature resistance, and extremely high chemical stability, and is often used as a surface protective layer to prevent metal oxidation; the transmittance of the prepared film can be maintained at around 80%, the square resistance is 62.4Ω / sq, and both transmittance and conductivity are lost; silver has stable chemical properties, low activity, is not easily corroded by chemicals, and has excellent thermal and electrical conductivity. A dense Ag coating was formed on the surface of CuNWs using a liquid-phase reduction method, resulting in a Cu-Ag core-shell nanowire structure. With simple post-processing, the sheet resistance and transmittance were maintained at 29Ω / sq and 84%. Although Ag-coated CuNWs improve the oxidation resistance of the CuNWs transparent electrode, Ag is susceptible to corrosion by sulfides in the air, which can lead to a loss of the photoelectric properties of the Ag-CuNWs film. Zinc oxide (ZnO) and aluminum oxide (Al2O3) are both wide-bandgap semiconductor materials with high transmittance or excellent conductivity in visible light. The AZO / Al2O3 protective layer was deposited on the surface of Cu nanofibers using atomic deposition technology (ALD). The AZO / Al2O3-Cu composite transparent electrode prepared after annealing at 250°C for 1h has a low square resistance (<20Ω / sq) and a high transmittance (<79%). Conductive polymers are widely used in the preparation of transparent functional films due to their combined conductivity and transmittance. They can be used as hole transport layers or directly as electrodes.Polypyrrole-coated CuNWs (Cu@PPy) were prepared using liquid-phase reduction technology. After being placed in air for 1 hour, the square resistance increased by 2 to 3 times, and the stability was poor. In addition, hydrazine hydrate (toxic) was used as a reducing agent in the preparation process, and its safety and stability need to be improved.

[0035] It can be seen that the current coating modification methods such as metals, oxides, and conductive polymers all have the disadvantages of high temperature, high energy consumption, poor stability, and general conductive transmittance. Therefore, this application adopts a simple, safe, and high-yield liquid phase synthesis method to prepare a conductive material with a new structure, which has high transmittance and conductivity, and has high stability.

[0036] Furthermore, the conductive polymer is polymerized with the copper nanowire core-shell structure through free radicals.

[0037] Specifically, the diameter of the copper nanowires may be 50 to 200 nm, 80 to 180 nm, or 100 to 150 nm.

[0038] Specifically, the coating layer includes one or more of silver, zinc, tin, nickel, titanium, silver oxide, zinc oxide, tin oxide, nickel oxide or titanium dioxide. The conductive material is coated with a metal or metal oxide coating layer to improve the stability of the conductive material.

[0039] Specifically, the conductive polymer includes one or more of polyethylenedioxythiophene (PEDOT), polypyrrole, polythiophene, polyphenylene, polyphenylene vinylene, or polyaniline. Conductive polymers are widely used in the preparation of transparent functional films due to their combined conductivity and light transmittance, serving as hole transport layers or directly as electrodes. Conductive materials grafted with conductive polymers exhibit excellent light transmittance and conductivity.

[0040] Specifically, the mass ratio of the copper nanowires, the coating layer and the conductive polymer is 1:1-1.5:10-1000.

[0041] Specifically, the molecular weight of the conductive polymer may be 10,000 to 100,000, or 20,000 to 90,000, or 50,000 to 80,000.

[0042] The present application also provides a method for preparing a conductive material, comprising: mixing an inorganic copper salt precursor, a reducing agent, and a dispersant in an alkaline solution, heating the solution to react and obtain copper nanowires; adding a weak acid and polyvinyl pyrrolidone to the copper nanowires, mixing, adding a metal salt and an ion control agent, reacting, and centrifuging to obtain a copper nanowire core-shell structure material; modifying the copper nanowire core-shell structure material with an acid, and adding a conductive polymer under the action of a silane coupling agent to obtain a conductive material. The present application adopts a liquid phase synthesis method, which is a hydrothermal liquid phase synthesis method, and can produce conductive materials on a large scale under low-cost and low-temperature conditions.

[0043] Furthermore, the inorganic copper salt precursor includes one or more of copper nitrate, copper chloride dihydrate, copper chloride or copper bromide.

[0044] Furthermore, the reducing agent includes one or more of glucose, sodium citrate, ascorbic acid or borohydride.

[0045] Furthermore, the dispersant includes one or more of polyvinylpyrrolidone (PVP), oleylamine or octadecylamine.

[0046] Furthermore, the alkaline solution includes one or more of ammonia water, sodium hydroxide solution or potassium hydroxide solution.

[0047] Furthermore, the metal salt includes one or more of silver nitrate, zinc chloride, tin chloride, nickel acetylacetonate, titanium acetylacetonate or silver acetylacetonate.

[0048] Furthermore, the ion control agent includes one or more of sodium chloride, potassium chloride, sodium bromide or potassium bromide. The ion control agent plays a role in controlling the aspect ratio of the growth of the conductive material.

[0049] Furthermore, the acid includes one or more of hydrochloric acid, nitric acid, or sulfuric acid. Preferably, dilute hydrochloric acid is used to modify the copper nanowire core-shell structure material. The concentration of the hydrochloric acid is 0.1 mol / L.

[0050] Furthermore, the silane coupling agent includes one or more of vinyltriethoxysilane, vinyltrimethoxysilane or vinyltrimethoxyethoxysilane.

[0051] Furthermore, the conductive polymer includes one or more of polyethylenedioxythiophene, polypyrrole, polythiophene, polyphenylene, polyphenylene vinylene or polyaniline.

[0052] Specifically, the heating reaction temperature can be 100-200°C, 120-180°C, or even 150-160°C. Temperature primarily affects the reduction rate of the precursor during the reaction and the thermodynamic equilibrium of nanowire seed growth. When the reaction temperature is low, the reduction rate of the precursor in the solution is low, which reduces the nanowire growth rate, resulting in a longer reaction time, shorter nanowire length, and lower yield. Increasing the temperature can accelerate the reaction rate and reduce the required reaction time, thereby increasing nanowire length and yield. Meanwhile, the growth of nanowire seed crystals requires energy, and low temperatures are insufficient to provide the energy required for one-dimensional nanowire seed growth. Increasing the temperature can promote nanowire growth, but excessively high reaction temperatures can lead to nanowire breakage and reduce the desired aspect ratio. Furthermore, excessively high reaction temperatures can also accelerate the reduction rate of the precursor, making nanowire formation difficult. Therefore, relatively high temperatures promote the synthesis of conductive material nanowires.

[0053] Specifically, the heating reaction time can be 4 to 6 hours, or even 5 hours. At relatively high reaction temperatures, the precursor in the solution undergoes a rapid reduction rate during the reaction, generating nanowire nuclei of the desired size. As the reaction time increases, the nanowire nuclei then grow into one-dimensional seed crystals. However, excessively long reaction times do not result in infinite nanowire length increases. Therefore, controlling the reaction time allows the production of nanowire materials with a specific aspect ratio.

[0054] Specifically, the concentration of the inorganic copper salt precursor can be 2.0-6.0 g / L, 3.0-5.0 g / L, or even 4.0 g / L. The acyl functional groups of PVP can coordinate with copper and silver ions, adsorbing them on specific crystal planes through coordination, causing the nanowire seeds to anisotropically grow into nanowires. Therefore, what affects the growth of nanowires is the molar ratio of PVP to the precursor. When the average molecular weight of PVP (K30) and the reaction addition amount are constant (increasing the amount of PVP added will also increase the viscosity of the reaction solution system and increase the difficulty of the synthesis experiment), when the concentration of the inorganic copper salt precursor is too low, PVP will cover the nanowire seeds over a large area, reducing the selectivity of growth on different crystal faces. The final product may be a mixture of nanoparticles or a small amount of nanowire products; increasing the concentration of the precursor can reduce the coating area of PVP on the nanowire seeds, promote the anisotropic growth of the nanowire seeds, and obtain the desired nanowire material; when the concentration of the precursor is too high, PVP cannot adsorb and cover the specific crystal faces of the nanowire seeds, resulting in difficulty in anisotropic growth of the seeds and the inability to generate nanowire materials.

[0055] In a specific implementation, the method for preparing the conductive material includes:

[0056] (1) An inorganic copper salt is used as a precursor, a reducing agent and a dispersant are added to an alkaline aqueous solution, and the mixture is heated at a constant temperature. After the reaction is completed, the copper nanowires are obtained by centrifugation;

[0057] (2) Adding a mixed solution of an appropriate amount of diluted weak acid and a small amount of polyvinyl pyrrolidone solution to the prepared copper nanowire solution, transferring the solution to a reaction bottle, adding an inorganic salt or organic metal salt solution, an ion control agent, etc. after constant temperature magnetic stirring, continuing stirring and adjusting the appropriate temperature, and using a liquid phase reduction method to form a metal or metal oxide coating layer on the surface of CuNWs to obtain a copper nanowire core-shell structure material; then transferring the reaction product solution to a centrifuge tube and placing it in a centrifuge for centrifugal treatment, and obtaining a copper nanowire core-shell structure material deposited at the bottom after centrifugation three times;

[0058] (3) The copper nanowire core-shell structure material is then hydroxylated and diluted to an appropriate concentration using a dilute acid. Under the action of a silane coupling agent, a conductive polymer material is added to synthesize a new copper nanowire core-shell structure conductive material having a conjugated polymer.

[0059] An embodiment of the present application further provides a conductive film, which includes the above-mentioned conductive material or the conductive material prepared by the above-mentioned preparation method.

[0060] In some embodiments of the present application, the light transmittance of the conductive film may be 85% to 93%, or 85% to 90%.

[0061] In some embodiments of the present application, the sheet resistance of the conductive film may be 10 to 40 Ω / sq, 15 to 35 Ω / sq, or 20 to 30 Ω / sq.

[0062] In a specific implementation, a film-forming material is added to the prepared conductive material, and then a coating method is used to prepare the conductive film. Specifically, the film-forming material includes one or more of nitrocellulose, cellulose acetate, carboxymethyl cellulose, resin-modified carboxymethyl cellulose, resin-modified hydroxyethyl cellulose, ethyl cellulose, nitrile ethyl cellulose, or hydroxyethyl cellulose.

[0063] The following describes the details in conjunction with specific embodiments.

[0064] Example 1

[0065] The present embodiment provides a method for preparing a conductive film, comprising the following steps:

[0066] (1) diluting the conductive material: diluting 1.0 wt% of the conductive material in an alcohol / water solution (ethanol / water volume ratio of 1:5 to 1:10) to prepare a 100 g solution, adding 0.10 g of sodium dodecylbenzenesulfonate as a dispersion stabilizer, and then adding 2 g of a polymer resin modified carboxymethyl cellulose with a molecular weight of about 10,000, ultrasonically dispersing for 10 to 20 minutes, centrifuging at a speed of 1000 rpm for 10 minutes, and collecting the supernatant to obtain a composite conductive coating of the conductive material;

[0067] (2) Select a substrate, clean it with ethanol, rinse it twice with deionized water, dry it, and set aside;

[0068] (3) The composite conductive coating solution was coated on a substrate (the substrate material was a PET transparent substrate with a transmittance of 91%, a haze of 0.3%, and a thickness of 0.1 mm) by coating, and heated for 2 minutes at a temperature of 70° C. to obtain a conductive film.

[0069] The method for preparing the conductive material in step (1) of this embodiment includes:

[0070] a) adding 0.2 g of copper chloride, 1.0 g of PVP, 0.5 g of ascorbic acid, and 60 mL of ethylene glycol to a 150 mL three-necked flask, adjusting the pH to a weakly alkaline state with 0.5% aqueous ammonia, and then placing the mixture in an oil bath at 160-180° C. and stirring to mix uniformly for 4-5 hours. After the reaction is complete, the mixture is centrifuged to obtain copper nanowires;

[0071] b) The copper nanowire solution obtained by the reaction was mixed with a diluted weak acid and a polyvinyl pyrrolidone aqueous solution in a ratio of 4:11:4 and injected into a reaction flask. After constant temperature magnetic stirring for 3 minutes, 0.26g of silver nitrate solution and an ion control agent were added, and stirring was continued for 10 to 30 minutes to complete the reaction;

[0072] c) transferring the reaction product solution to a centrifuge tube, adding ethylene glycol as a cleaning solvent, and centrifuging in a centrifuge to remove excess organic matter. After centrifugation three times, a copper nanowire core-shell structure material is obtained.

[0073] d) The copper nanowire core-shell structure material was hydroxylated using dilute hydrochloric acid and diluted to an appropriate concentration. 2.5 g of a conductive polymer, polyethylenedioxythiophene, was added to the mixture in the presence of 0.2 g of a silane coupling agent. The mixture was heated at a constant temperature of 50-70° C. for 1-2 hours under nitrogen protection to synthesize a conductive material.

[0074] Example 2

[0075] The present embodiment provides a method for preparing a conductive film, comprising the following steps:

[0076] (1) diluting the conductive material: diluting 1.5 wt% of the conductive material in an alcohol / water solution (ethanol / water volume ratio of 1:5 to 1:10) to prepare a 100 g solution, adding 0.15 g of sodium dodecylbenzenesulfonate as a dispersion stabilizer, and then adding 2 g of a polymer resin modified carboxymethyl cellulose with a molecular weight of about 10,000, ultrasonically dispersing for 10 to 20 minutes, centrifuging at a speed of 1000 rpm for 10 minutes, and collecting the supernatant to obtain a composite conductive coating of the conductive material;

[0077] (2) Select a substrate, clean it with ethanol, rinse it twice with deionized water, dry it, and set aside;

[0078] (3) The composite conductive coating solution was coated on a substrate (the substrate material was a PET transparent substrate with a transmittance of 91%, a haze of 0.3%, and a thickness of 0.1 mm) by coating, and heated for 2 minutes at a temperature of 70° C. to obtain a conductive film.

[0079] The method for preparing the conductive material in step (1) of this embodiment includes:

[0080] a) adding 0.2 g of copper chloride, 1.0 g of PVP, 0.5 g of ascorbic acid, and 60 mL of ethylene glycol to a 150 mL three-necked flask, adjusting the pH to a weakly alkaline state with 0.5% aqueous ammonia, and then placing the mixture in an oil bath at 160-180° C. and stirring to mix uniformly for 4-5 hours. After the reaction is complete, the mixture is centrifuged to obtain copper nanowires;

[0081] b) The copper nanowire solution obtained by the reaction was mixed with a diluted weak acid and a polyvinyl pyrrolidone aqueous solution in a ratio of 4:11:4 and injected into a reaction flask. After constant temperature magnetic stirring for 3 minutes, 0.26g of silver nitrate solution and an ion control agent were added, and stirring was continued for 10 to 30 minutes to complete the reaction;

[0082] c) transferring the reaction product solution to a centrifuge tube, adding ethylene glycol as a cleaning solvent, and centrifuging in a centrifuge to remove excess organic matter. After centrifugation three times, a copper nanowire core-shell structure material is obtained.

[0083] d) The copper nanowire core-shell structure material was hydroxylated using dilute hydrochloric acid and diluted to an appropriate concentration. 2.5 g of a conductive polymer, polyethylenedioxythiophene, was added to the mixture in the presence of 0.2 g of a silane coupling agent. The mixture was heated at a constant temperature of 50-70° C. for 1-2 hours under nitrogen protection to synthesize a conductive material.

[0084] Example 3:

[0085] The present embodiment provides a method for preparing a conductive film, comprising the following steps:

[0086] (1) diluting the conductive material: diluting 2.0 wt% of the conductive material in an alcohol / water solution (ethanol / water volume ratio of 1:5 to 1:10) to prepare a 100 g solution, adding 0.2 g of sodium dodecylbenzenesulfonate as a dispersion stabilizer, and then adding 2 g of a polymer resin modified carboxymethyl cellulose with a molecular weight of about 10,000, ultrasonically dispersing for 10 to 20 minutes, centrifuging at a speed of 1000 rpm for 10 minutes, and collecting the supernatant to obtain a composite conductive coating of the conductive material;

[0087] (2) Select a substrate, clean it with ethanol, rinse it twice with deionized water, dry it, and set aside;

[0088] (3) The composite conductive coating solution was coated on a substrate (the substrate material was a PET transparent substrate with a transmittance of 91%, a haze of 0.3%, and a thickness of 0.1 mm) by coating, and heated for 2 minutes at a temperature of 70° C. to obtain a conductive film.

[0089] The method for preparing the conductive material in step (1) of this embodiment includes:

[0090] a) adding 0.2 g of copper chloride, 1.0 g of PVP, 0.5 g of ascorbic acid, and 60 mL of ethylene glycol to a 150 mL three-necked flask, adjusting the pH to a weakly alkaline state with 0.5% aqueous ammonia, and then placing the mixture in an oil bath at 160-180° C. and stirring to mix uniformly for 4-5 hours. After the reaction is complete, the mixture is centrifuged to obtain copper nanowires;

[0091] b) The copper nanowire solution obtained by the reaction was mixed with a diluted weak acid and a polyvinyl pyrrolidone aqueous solution in a ratio of 4:11:4 and injected into a reaction flask. After constant temperature magnetic stirring for 3 minutes, 0.26g of silver nitrate solution and an ion control agent were added, and stirring was continued for 10 to 30 minutes to complete the reaction;

[0092] c) transferring the reaction product solution to a centrifuge tube, adding ethylene glycol as a cleaning solvent, and centrifuging in a centrifuge to remove excess organic matter. After centrifugation three times, a copper nanowire core-shell structure material is obtained.

[0093] d) The copper nanowire core-shell structure material was hydroxylated using dilute hydrochloric acid and diluted to an appropriate concentration. 2.5 g of a conductive polymer, polyethylenedioxythiophene, was added to the mixture in the presence of 0.2 g of a silane coupling agent. The mixture was heated at a constant temperature of 50-70° C. for 1-2 hours under nitrogen protection to synthesize a conductive material.

[0094] Example 4:

[0095] The present embodiment provides a method for preparing a conductive film, comprising the following steps:

[0096] (1) diluting the conductive material: diluting 1.5 wt% of the conductive material in an alcohol / water solution (ethanol / water volume ratio of 1:5 to 1:10) to prepare a 100 g solution, adding 0.2 g of sodium polyacrylate as a dispersion stabilizer, and then adding 2 g of a polymer resin modified carboxymethyl cellulose with a molecular weight of about 10,000, ultrasonically dispersing for 10 to 20 minutes, centrifuging at a speed of 1000 rpm for 10 minutes, and collecting the supernatant to obtain a composite conductive coating of the conductive material;

[0097] (2) Select a substrate, clean it with ethanol, rinse it twice with deionized water, dry it, and set aside;

[0098] (3) The composite conductive coating solution was coated on a substrate (the substrate material was a PET transparent substrate with a transmittance of 91%, a haze of 0.3%, and a thickness of 0.1 mm) by coating, and heated for 2 minutes at a temperature of 70° C. to obtain a conductive film.

[0099] The method for preparing the conductive material in step (1) of this embodiment includes:

[0100] a) adding 0.2 g of copper chloride, 1.0 g of PVP, 0.5 g of ascorbic acid, and 60 mL of ethylene glycol to a 150 mL three-necked flask, adjusting the pH to a weakly alkaline state with 0.5% aqueous ammonia, and then placing the mixture in an oil bath at 160-180° C. and stirring to mix uniformly for 2-3 h. After the reaction is complete, the mixture is centrifuged to obtain copper nanowires;

[0101] b) The copper nanowire solution obtained by the reaction was mixed with a diluted weak acid and a polyvinyl pyrrolidone aqueous solution in a ratio of 4:11:4 and injected into a reaction flask. After constant temperature magnetic stirring for 3 minutes, 0.26g of silver nitrate solution and an ion control agent were added, and stirring was continued for 10 to 30 minutes to complete the reaction;

[0102] c) transferring the reaction product solution to a centrifuge tube, adding ethylene glycol as a cleaning solvent, and centrifuging in a centrifuge to remove excess organic matter. After centrifugation three times, a copper nanowire core-shell structure material is obtained.

[0103] d) The copper nanowire core-shell structure material was hydroxylated using dilute hydrochloric acid and diluted to an appropriate concentration. 2.5 g of a conductive polymer, polyethylenedioxythiophene, was added to the mixture in the presence of 0.2 g of a silane coupling agent. The mixture was heated at a constant temperature of 50-70° C. for 1-2 hours under nitrogen protection to synthesize a conductive material.

[0104] Performance Testing

[0105] Comparative Example 1: The conductive polymer polyethylenedioxythiophene in the conductive material system of Example 1 was removed, and the other components and their synthesis dosages remained unchanged. A transparent conductive film was prepared according to the method for preparing a conductive film in the example.

[0106] For the conductive film products of Examples 1 to 4 and Comparative Example 1, the square resistance of the patterned transparent conductive film was tested using a four-probe tester, the transmittance and haze of the patterned transparent conductive film were tested using a photoelectric haze meter, and the adhesion was tested using 3M610 tape. The results are shown in Table 1.

[0107] Table 1 Performance test results

[0108]

[0109]

[0110] It can be seen from the above table that when the same substrate is used, the transparent conductive film made by adding the conductive liquid material with polyethylene dioxythiophene has better optical transmittance, lower haze, and lower square resistance.

[0111] This application adopts a liquid phase synthesis method to synthesize and prepare a new conductive material. The overall preparation scheme is simple to operate, the reaction temperature is low (<200°C), and the synthesis cost is low; the conductive material and the conductive film are easy to scale up for production, and the prepared transparent conductive film is evenly dispersed, the conductivity and transmittance are controllable, and it has good antioxidant properties. The transparent conductive film can maintain long-term stability at high temperatures (<200°C) and high humidity.

[0112] The above is a detailed introduction to a conductive material and a conductive film and a preparation method thereof provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A conductive material, characterized in that The conductive material comprises copper nanowires, a coating layer and a conductive polymer; the coating layer is coated on the surface of the copper nanowire to form a copper nanowire core-shell structure material with the copper nanowire as the core and the coating layer as the shell, and the coating layer comprises a metal or a metal oxide; the conductive polymer and the copper nanowire core-shell structure material form a copolymer; The conductive polymer is combined with the copper nanowire core-shell structure material to form a copolymer through a silane coupling agent, and the silane coupling agent includes one or more of vinyltriethoxysilane, vinyltrimethoxysilane or vinyltrimethoxyethoxysilane; The conductive polymer includes one or more of polyethylenedioxythiophene, polypyrrole, polythiophene, polyphenylene, polyphenylene vinylene or polyaniline; The conductive polymer and the copper nanowire core-shell structure material form a conjugated polymer copolymer.

2. The conductive material according to claim 1, wherein The diameter of the copper nanowire is 50-200 nm.

3. The conductive material according to claim 1, wherein The coating layer includes one or more of silver, zinc, tin, nickel, titanium, silver oxide, zinc oxide, tin oxide, nickel oxide or titanium dioxide.

4. The conductive material according to claim 1, wherein The mass ratio of the copper nanowire, the coating layer and the conductive polymer is 1:1-1.5:10-1000.

5. The conductive material according to claim 3, characterized in that The molecular weight of the conductive polymer is 10,000 to 100,000.

6. A method for preparing a conductive material, characterized in that: include: An inorganic copper salt precursor, a reducing agent, and a dispersant are mixed in an alkaline solution and heated to react to obtain copper nanowires; Adding a weak acid and polyvinyl pyrrolidone to the copper nanowires, adding a metal salt and an ion control agent after mixing, reacting and centrifuging to obtain a copper nanowire core-shell structure material; modifying the copper nanowire core-shell structure material with an acid, and adding a conductive polymer under the action of a silane coupling agent to obtain the conductive material; Wherein, the silane coupling agent includes one or more of vinyltriethoxysilane, vinyltrimethoxysilane or vinyltrimethoxyethoxysilane; The conductive polymer includes one or more of polyethylenedioxythiophene, polypyrrole, polythiophene, polyphenylene, polyphenylene vinylene or polyaniline; The conductive polymer and the copper nanowire core-shell structure material form a conjugated polymer copolymer.

7. The method for preparing a conductive material according to claim 6, wherein: The inorganic copper salt precursor includes one or more of copper nitrate, copper chloride dihydrate, copper chloride or copper bromide; and / or the reducing agent includes one or more of glucose, sodium citrate, ascorbic acid or borohydride; and / or the dispersant includes one or more of polyvinyl pyrrolidone, oleylamine or octadecylamine; and / or the alkaline solution includes one or more of ammonia water, sodium hydroxide solution or potassium hydroxide solution; and / or the metal salt includes one or more of silver nitrate, zinc chloride, tin chloride, nickel acetylacetonate, titanium acetylacetonate or silver acetylacetonate; and / or the ion control agent includes one or more of sodium chloride, potassium chloride, sodium bromide or potassium bromide; and / or the acid includes one or more of hydrochloric acid, nitric acid or sulfuric acid.

8. The method for preparing a conductive material according to claim 6, wherein: The temperature of the heating reaction is 100-200° C., the time of the heating reaction is 4-6 hours, and the concentration of the inorganic copper salt precursor is 2.0-6.0 g / L.

9. A conductive film, characterized in that: The conductive film comprises the conductive material according to any one of claims 1 to 5 or the conductive material prepared by the preparation method according to any one of claims 6 to 8.

10. The conductive film according to claim 9, wherein The light transmittance of the conductive film is 85% to 93%; and / or the sheet resistance of the conductive film is 10 to 40Ω / sq.

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