Transparent electrode material, preparation method therefor and use thereof

Abstract

The present application provides a transparent electrode material, a preparation method therefor, and a use of the transparent electrode material in conductive ink and transparent conductive films. The transparent electrode material comprises a metal nanowire, a protective layer wrapping the surface of the metal nanowire, and a resin layer wrapping the surface of the protective layer; the protective layer is a tin oxide layer, a silicon oxide layer, or a titanium oxide layer.

Description

Transparent electrode material, method for preparing same, and use thereof

[0001] This application is based on and claims priority to Chinese Patent Application No. 202410423944.3, filed on April 9, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of nanomaterials, and in particular to a transparent electrode material, a method for preparing the transparent electrode material, and use of the transparent electrode material in conductive ink and transparent conductive film. BACKGROUND

[0003] Currently, transparent conductive films are mostly prepared using ITO, metal mesh, metal nanowires, etc. Among them, metal nanowires, especially silver nanowires, have excellent electrical conductivity, optical properties, and flexibility, and are considered to be the most likely material to replace traditional ITO transparent electrodes, and can be applied to flexible foldable devices, smart wearable devices, photovoltaic cells, touch screens, and defogging devices, etc. However, a common problem in the application of metal nanowires (such as silver nanowires) is that they are easily oxidized by water, oxygen, and chemical reagents, and the melting point is reduced to 200-300°C, which is prone to thermal melting, and the thermal stability is poor. Oxidation and thermal melting of metal nanowires (such as silver nanowires) will greatly deteriorate their electrical conductivity and optical properties, and even cause them to fail. Therefore, it is urgent to improve the chemical stability and thermal stability of metal nanowires.

[0004] To improve this problem, the existing technology mainly uses electroplating or atomic deposition to plate or deposit a layer of metal oxide protective layer on the surface of the substrate coated with metal nanowires (such as silver nanowires), but this method has the following defects: on the one hand, it requires expensive equipment support, and the cost is high, on the other hand, even if a protective layer is covered on the surface of the film material, it can only play an anti-oxidation role, but it has no good effect on the thermal stability of the metal nanowires. The metal nanowires under the protective layer will still melt and break at the position where they are connected to each other when a high-density current passes through, causing the electrical conductivity to deteriorate.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a transparent electrode material, a method for preparing the transparent electrode material, and use of the transparent electrode material in conductive ink and transparent conductive film, which can simultaneously improve the physical and chemical stability of metal nanowires.

[0007] To achieve the above-mentioned application purposes, the application adopts the following technical solutions: a transparent electrode material, comprising metal nanowires, a protective layer coated on the surface of the metal nanowires, and a resin layer coated on the surface of the protective layer; the protective layer is a tin oxide layer, or a silicon oxide layer, or a titanium oxide layer.

[0008] As a further improved technical solution of the application, the thickness of the protective layer is 1 nm to 10 nm.

[0009] As a further improved technical solution of the application, the resin layer is one of a polyester resin, an epoxy resin, and a polypropylene resin.

[0010] To achieve the above-mentioned application purposes, the application further provides a preparation method of a transparent electrode material, comprising the following steps:

[0011] forming a protective layer on the surface of the metal nanowires to form metal nanowires coated with the protective layer, wherein the protective layer is a tin oxide layer, or a silicon oxide layer, or a titanium oxide layer;

[0012] dispersing the metal nanowires coated with the protective layer in an aqueous solvent to form a metal nanowire dispersion liquid;

[0013] adding resin to the metal nanowire dispersion liquid and mixing uniformly to form a metal nanowire mixture liquid, and simultaneously forming a transparent electrode material coated with a resin layer on the surface of the protective layer.

[0014] As a further improved technical solution of the application, the content of the resin in the metal nanowire mixture liquid is less than 5 wt.%.

[0015] As a further improved technical solution of the application, the step of "adding resin to the metal nanowire dispersion liquid and mixing uniformly to form a metal nanowire mixture liquid" specifically comprises the following steps:

[0016] dissolving the resin in deionized water to dilute into a resin liquid;

[0017] adding the resin liquid to the metal nanowire dispersion liquid and mixing uniformly to form a metal nanowire mixture liquid.

[0018] As a further improved technical solution of the application, the mass concentration of the resin liquid is 28% to 35%.

[0019] As a further improved technical solution of the application, the mass ratio of the metal nanowires to the aqueous solvent in the metal nanowire dispersion liquid is 4% to 40%.

[0020] As a further improved technical solution of the application, the protective layer is a tin oxide layer; the step of "forming a protective layer on the surface of the metal nanowires" specifically comprises the following steps:

[0021] obtaining a metal nanowire solution, the metal nanowire solution comprising a non-aqueous solvent and metal nanowires dispersed in the non-aqueous solvent;

[0022] dispersing a stannous salt in the non-aqueous solvent to form a stannous salt solution;

[0023] adding the stannous salt solution to the metal nanowire solution in a preset ratio to obtain a mixed system;

[0024] adding a preset amount of deionized water to the mixed system and mixing uniformly to form a reaction solution, and meanwhile, coating a protective layer on the surface of the metal nanowires.

[0025] As a further improved technical solution of the present application, the mass concentration of the metal nanowire solution is 0.45 wt.% to 0.52 wt.%.

[0026] As a further improved technical solution of the present application, the volume concentration of the stannous salt solution is 0.08 vol.% to 0.13 vol.%.

[0027] As a further improved technical solution of the present application, the mass ratio of the stannous salt solution to the metal nanowire solution is 1 to 8:4.

[0028] As a further improved technical solution of the present application, the mass ratio of Sn2+ in the stannous salt solution added to the mixed system to the deionized water added to the mixed system is 0.1% to 5%.

[0029] As a further improved technical solution of the present application, after coating the protective layer on the surface of the metal nanowires, the preparation method further comprises the following steps:

[0030] using a centrifuge or a cross-flow machine to clean and purify the reaction solution to obtain the metal nanowires coated with the protective layer.

[0031] To achieve the above-mentioned application purposes, the present application further provides an application of the above-mentioned transparent electrode material in conductive ink and transparent conductive film, wherein the conductive ink and the transparent conductive film comprise the above-mentioned transparent electrode material.

[0032] To achieve the above-mentioned application purposes, the present application further provides an application of the transparent electrode material obtained by the above-mentioned preparation method in conductive ink and transparent conductive film. The transparent conductive film comprises the transparent electrode material prepared by the above-mentioned preparation method; or the transparent conductive film is prepared by using the conductive ink prepared from the above-mentioned transparent electrode material.

[0033] The beneficial effects of the present application are: the transparent electrode material in the present application, by coating a layer of protective layer on the surface of metal nanowire, and then coating a layer of resin layer on the surface of the protective layer, on the one hand, the protective layer (tin oxide layer, or silicon oxide layer, or titanium oxide layer) can block the influence of the external environment on the metal nanowire, block the contact of the metal nanowire with the external oxygen, water vapor and the like, improve the water oxygen resistance and oxidation resistance of the metal nanowire, at the same time, improve the heat resistance of the metal nanowire, and the anodic oxidation resistance when power is connected in high temperature and high humidity; on the other hand, coating a layer of resin layer on the periphery of the protective layer can protect the protective layer from chemical corrosion, so that the protective layer can effectively protect the metal nanowire, and at the same time improve the physical stability and chemical stability of the metal nanowire. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural schematic diagram of the transparent electrode material in the present application;

[0035] Figure 2 (a) is a micrograph after heat resistance test of Example 1 of the present application;

[0036] Figure 2 (b) is a micrograph after heat resistance test of Comparative Example 1 of the present application;

[0037] Figure 2 (c) is a micrograph after heat resistance test of Comparative Example 2 of the present application;

[0038] Figure 2 (d) is a micrograph after heat resistance test of Comparative Example 3 of the present application;

[0039] Figure 3 (a) is an SEM photograph after heat resistance test of Comparative Example 1 of the present application;

[0040] Figure 3 (b) is an SEM photograph after heat resistance test of Comparative Example 3 of the present application;

[0041] Figure 4 (a) is a micrograph after anodic oxidation resistance test of Comparative Example 1 of the present application;

[0042] Figure 4 (b) is a micrograph after anodic oxidation resistance test of Comparative Example 3 of the present application. DETAILED DESCRIPTION

[0043] The present application will be described in detail below in conjunction with each embodiment shown in the drawings. Please refer to Figures 1-4, which show the preferred embodiments of the present application.

[0044] Please refer to Fig. 1, the present application provides a kind of transparent electrode material 10, including metal nanowire 1, protective layer 2 covered in the surface of metal nanowire 1, resin layer 3 covered in the surface of protective layer 2;The protective layer 2 is tin oxide layer, or silicon oxide layer, or titanium oxide layer.In the present application, on the one hand, by protective layer 2 (tin oxide layer, or silicon oxide layer, or titanium oxide layer) is covered on the outer surface of metal nanowire 1, can block the influence of external environment to metal nanowire 1, block the contact of metal nanowire 1 with external oxygen, water vapor etc., improve the oxidation resistance of metal nanowire 1 against water and oxygen, while, coated protective layer 2 (tin oxide layer, or silicon oxide layer, or titanium oxide layer) high temperature resistance, can prevent its internal metal nanowire 1 from melting and breaking in use due to overheating, so as not to affect the conductive performance of metal nanowire 1, improve the heat resistance of metal nanowire 1 and the anodic oxidation resistance when high temperature and high humidity power on;On the other hand, a layer of resin layer 3 is coated on the periphery of protective layer 2, to resist some chemical corrosion of the outside, such as anti-ink corrosion and anti-84 corrosion, make up for the deficiency of protective layer 2 (tin oxide layer, or silicon oxide layer, or titanium oxide layer), can protect protective layer 2 from chemical corrosion, so that the protective layer 2 can effectively protect the metal nanowire 1, even if the transparent electrode material 10 contacts ink, disinfectant and some other materials containing acidic substances in actual application, the conductive performance and optical performance of the metal nanowire 1 will not be affected, the metal nanowire 1 is protected by the cooperation of protective layer 2 and resin layer 3, and the physical stability and chemical stability of the metal nanowire 1 are improved.

[0045] In a specific embodiment, the metal nanowire is a silver nanowire. Of course, it is not limited thereto, and in other embodiments, the metal nanowire can also be a gold nanowire, or a copper nanowire, or a silver-coated copper nanowire, etc.

[0046] Further, the thickness of the protective layer 2 is 1 nm to 10 nm, preferably, the thickness of the protective layer 2 is 3 nm to 5 nm. Thus, the protective layer 2 will not affect the conductive performance of the metal nanowire 1.

[0047] In a specific embodiment, the protective layer 2 is a tin oxide layer. It is known that the tin oxide layer has good conductive performance and heat resistance. By controlling the thickness of the tin oxide layer to be between 1 nm and 10 nm, the conductive performance of the metal nanowire can be maintained, and the oxidation resistance and thermal stability of the metal nanowire can be greatly improved. Of course, it is not limited thereto, and in other embodiments, the protective layer 2 can also be set as a silicon oxide layer or a titanium oxide layer.

[0048] Specifically, the resin layer can be selected from polyester, epoxy, polypropylene and other resins with good acid resistance, alkali resistance and other chemical corrosion, so that after coating a layer of resin layer on the outer surface of the protective layer, the disadvantage of the protective layer not being resistant to acid corrosion can be compensated for, and the transparent electrode material 10 has good chemical corrosion resistance without affecting the conductivity of the metal nanowire.

[0049] Specifically, when the metal nanowire coated with the protective layer 2 is placed in the resin liquid, the resin in the resin liquid is adsorbed on the surface of the protective layer by intermolecular van der Waals force to form the resin layer 3.

[0050] Further, the present application also provides a preparation method of the above transparent electrode material 10, which comprises the following steps:

[0051] S1: forming a layer of protective layer 2 on the surface of the metal nanowire 1 to form the metal nanowire 1 coated with the protective layer 2, and the protective layer 2 is a tin oxide layer, or a silicon oxide layer, or a titanium oxide layer;

[0052] S2: dispersing the metal nanowire 1 coated with the protective layer 2 in an aqueous solvent to form a metal nanowire dispersion liquid;

[0053] S3: adding resin to the metal nanowire dispersion liquid and mixing uniformly to form a metal nanowire mixed liquid, and at the same time, forming a transparent electrode material 10 coated with a layer of resin layer 3 on the surface of the protective layer 2, wherein the content of the resin in the metal nanowire mixed liquid is less than 5 wt.%.

[0054] The preparation method of the transparent electrode material in the present application includes the following steps: S1, mixing resin with metal nanowires 1 coated with a protective layer 2, and coating a resin layer 3 outside the protective layer 2 to form a transparent electrode material 10 with a three-layer structure of “metal nanowire-protective layer-resin layer”. On the one hand, by coating the protective layer 2 (tin oxide layer or silicon oxide layer or titanium oxide layer) on the outer surface of the metal nanowires 1, the influence of the external environment on the metal nanowires 1 can be blocked, and the metal nanowires 1 can be prevented from contacting oxygen and water vapor in the external environment, thereby improving the oxidation resistance of the metal nanowires 1. In addition, the protective layer 2 (tin oxide layer or silicon oxide layer or titanium oxide layer) is resistant to high temperature, and can prevent the metal nanowires 1 inside from melting and breaking due to overheating during power supply, thereby not affecting the conductivity of the metal nanowires 1 and improving the heat resistance and anodic oxidation resistance of the metal nanowires 1 during power supply in high temperature and high humidity. On the other hand, by coating a resin layer 3 outside the protective layer 2, the chemical corrosion of the external environment can be resisted, and the shortcomings of the protective layer 2 (tin oxide layer or silicon oxide layer or titanium oxide layer) can be compensated for. The protective layer 2 can be protected from chemical corrosion, so that the protective layer 2 can effectively protect the metal nanowires 1. Even if the transparent electrode material 10 contacts some materials containing acidic substances such as ink and disinfectant in actual application, the conductivity and optical properties of the metal nanowires 1 will not be affected. The metal nanowires 1 are protected by the protective layer 2 and the resin layer 3, and the physical stability and chemical stability of the metal nanowires 1 are improved.

[0055] In a specific embodiment, the metal nanowires are silver nanowires. Of course, this is not limiting, and in other embodiments, the metal nanowires can also be gold nanowires, copper nanowires, silver-coated copper nanowires, etc.

[0056] In a specific embodiment, the protective layer 2 is a tin oxide layer. It can be understood that the tin oxide layer has good conductivity and heat resistance, and can greatly improve the oxidation resistance and thermal stability of the metal nanowires. Of course, this is not limiting, and in other embodiments, the protective layer can also be a silicon oxide layer or a titanium oxide layer.

[0057] In the following, the metal nanowires 1 are silver nanowires, and the protective layer 2 is a tin oxide layer. The step S1 in the preparation method of the transparent electrode material in the present application is described in detail. Of course, it can be understood that this is not limiting.

[0058] In a specific embodiment, step S1 specifically includes the following steps:

[0059] S11: Obtain a metal nanowire solution, which includes a non-aqueous solvent and metal nanowires dispersed in the non-aqueous solvent;

[0060] S12: dispersing the stannous salt in a non-aqueous solvent to form a stannous salt solution;

[0061] S13: adding the stannous salt solution to the metal nanowire solution in a preset proportion to obtain a mixed system;

[0062] S14: adding a preset amount of deionized water to the mixed system and mixing uniformly to form a reaction liquid, and at the same time, coating a protective layer 2 on the surface of the metal nanowire.

[0063] In the embodiment, a wet chemical method is used, and the metal nanowire solution after synthesis of the metal nanowire is directly used, that is, the silver nanowire is synthesized in ethylene glycol (a non-aqueous solvent) without a purification process, and the stannous salt solution and deionized water are directly added for coating reaction. Under the catalytic action of Ag+ on the surface of the silver nanowire, Sn2+ hydrolysis reaction generates tin oxide, forming a tin oxide layer coated on the surface of the silver nanowire. The operation is simple, and the cost is low. Of course, this is not limited, and in other embodiments, step S11 can also be: dispersing the metal nanowire in a non-aqueous solvent to form a metal nanowire solution, that is, the metal nanowire is purified after synthesis, and then dispersed in a non-aqueous solvent to form a metal nanowire solution for subsequent use. The non-aqueous solvent can be ethylene glycol or anhydrous ethanol.

[0064] Specifically, the chemical reaction mechanism of the coating reaction is as follows:

[0065]

[0066] .

[0067] Specifically, the mass concentration of the metal nanowire solution is 0.45wt.%~0.52wt.%, and the wire diameter of the metal nanowire is 25nm~30nm. For example, when the metal nanowire is silver nanowire, the mass concentration of the silver nanowire solution is 0.45wt.%~0.52wt.%, and the wire diameter of the silver nanowire is 25nm~30nm. That is, the mass concentration of the silver nanowire solution is any value in 0.45wt.%~0.52wt.%, such as 0.45wt.%, 0.48wt.%, 0.495wt.%, 0.5wt.%, 0.52wt.% and the like, which will not be listed here.

[0068] Further, the stannous salt in step S12 is dispersed in a non-aqueous solvent to form a stannous salt solution. The stannous salt can be T2E (2-ethylhexanoate stannous) or SnF2 (stannous fluoride), but is not limited thereto. The non-aqueous solvent can be anhydrous ethanol, but is not limited thereto. It is known that the water content of the non-aqueous solvent for the stannous salt and the silver nanowire is less than 2%, preferably less than 1%, so that the metal nanowire and the Sn 2+ The non-aqueous solvent is not reacted with the silver nanowire, and the coating reaction occurs only after a predetermined amount of deionized water is added to the mixed system in step S14.

[0069] Specifically, the volume concentration of the stannous salt solution is 0.08vol.%-0.13vol.%. For example, when the stannous salt is T2E, the volume concentration of the T2E solution is 0.08vol.%~0.13vol.%, i.e., the volume concentration of the T2E solution is any value in the range of 0.08vol.%~0.13vol.%, such as 0.08vol.%, 0.1vol.%, 0.13vol.% and the like, which is not exhaustive.

[0070] Further, the predetermined ratio in step S13 satisfies that the mass ratio of the stannous salt solution to the metal nanowire solution is 1-8:4. For example, when the mass of the silver nanowire solution is 200g, the mass of the T2E solution is 50-400g.

[0071] It is known that the specific amount of the stannous salt solution is adjusted according to the wire diameter of the metal nanowire. If the wire diameter of the metal nanowire is large, the specific surface area of the metal nanowire is large, and accordingly, the specific amount of the stannous salt solution is appropriately increased. Correspondingly, if the wire diameter of the metal nanowire is small, the specific surface area of the metal nanowire is small, and accordingly, the specific amount of the stannous salt solution is appropriately reduced.

[0072] Further, after the stannous salt solution is added to the metal nanowire solution in step S13, the preparation method further comprises the following steps:

[0073] The mixture of the stannous salt solution and the metal nanowire solution is placed on a magnetic stirrer and stirred at a temperature of 20-40℃ for 25-35min, so that the stannous salt solution and the metal nanowire solution are uniformly mixed to obtain a mixed system.

[0074] In a specific embodiment, the mixture of the stannous salt solution and the metal nanowire solution is placed on a magnetic stirrer and stirred for 30min, but is not limited thereto.

[0075] Further, the amount of deionized water added in step S14 is selected according to the amount of stannous salt in the stannous salt solution in the mixed system in step S13. Specifically, the mass ratio of stannous salt in the stannous salt solution added to the mixed system to the stannous salt in the stannous salt solution is 0.1% to 5%, preferably 1% to 1.2%, which is conducive to the above-mentioned coating reaction. 2+ The mass ratio of the deionized water added to the mixed system to the stannous salt in the stannous salt solution is 0.1% to 5%, preferably 1% to 1.2%, which is conducive to the above-mentioned coating reaction.

[0076] Further, after adding a predetermined amount of deionized water to the mixed system, the solution is placed on a magnetic stirrer at a speed of 500 rpm at a temperature of 20°C to 40°C for 30 min to 35 min to fully mix and evenly form a reaction solution, and then the reaction solution is removed from the magnetic stirrer and left to stand at room temperature for 6 to 18 h to allow the Sn 2+ The hydrolysis reaction (coating reaction) continues to in-situ coat a layer of tin oxide on the surface of the silver nanowire.

[0077] Further, after step S14 in the above step S1, the following step S15 is further included:

[0078] The reaction solution is cleaned and purified by a centrifuge or a cross-flow machine to obtain the metal nanowire 1 coated with the protective layer 2.

[0079] On the one hand, the above-mentioned impurity ions remaining in the coating reaction can be removed, thereby reducing the conductivity of the subsequent conductive ink and improving the electrochemical corrosion resistance of the transparent conductive film in use; on the other hand, the silver particles and silver short rods in the silver nanowire solution after the synthesis of the silver nanowire can be removed, thereby improving the purity of the silver nanowire and further improving the impedance stability of the final transparent conductive film.

[0080] Further, step S2 is specifically: dispersing the metal nanowire 1 coated with the protective layer 2 after cleaning and purification in step S15 in deionized water to form a metal nanowire dispersion liquid, which can obtain a metal nanowire dispersion liquid with good coating and impurity ion removal.

[0081] Further, the mass ratio of the metal nanowire to the deionized water in the metal nanowire dispersion liquid is 4% to 40%. Preferably, the mass ratio of the metal nanowire to the deionized water in the metal nanowire dispersion liquid is 14% to 16%.

[0082] Further, in the present embodiment, the resin layer uses polyester, epoxy, polypropylene, etc. which have good resistance to acid, alkali and other chemical corrosion, so that after coating the resin layer on the outer surface of the protective layer, the shortcomings of the protective layer not being resistant to acid corrosion can be compensated for, and the transparent electrode material has good chemical corrosion resistance without affecting the conductivity of the metal nanowire.

[0083] Further, the step S3 specifically comprises the following steps:

[0084] S31: dissolve the resin in deionized water to form a resin solution;

[0085] S32: add the resin solution to the metal nanowire dispersion liquid and mix uniformly to form a metal nanowire mixture.

[0086] In the process of adding the resin solution to the metal nanowire dispersion liquid and mixing uniformly to form a metal nanowire mixture, the resin in the resin solution is adsorbed on the surface of the tin oxide layer by intermolecular van der Waals force to form the resin layer.

[0087] In this application, by controlling the content of the resin in the metal nanowire mixture to be less than 5 wt.%, preferably 0.3 wt.%-1 wt.%, that is, controlling the addition ratio of the resin, the resin layer finally coated on the surface of the protective layer can make the finally formed transparent electrode material have excellent chemical corrosion resistance without affecting the conductivity of the metal nanowire.

[0088] Specifically, the mass concentration of the resin solution is 28%-35%.

[0089] Further, after adding a predetermined amount of the resin solution to the metal nanowire dispersion liquid, it is placed on a magnetic stirrer for stirring at a speed of 800 rpm for 2-5 h to make the solution mix uniformly to form a metal nanowire mixture, and the resin is uniformly coated on the surface of the protective layer to improve the chemical corrosion resistance of the final transparent electrode material.

[0090] Further, the application also provides a conductive ink, which comprises the above-mentioned transparent electrode material 10; or the conductive ink comprises the transparent electrode material 10 prepared by the above-mentioned preparation method.

[0091] In a specific embodiment, when preparing the conductive ink, a predetermined proportion of water-soluble resin is directly added to the metal nanowire mixture formed in step S3 of the above-mentioned transparent electrode material preparation method to stir uniformly to form the conductive ink, so that the metal nanowire mixture can be uniformly film-formed during subsequent coating, which is conducive to the preparation of the subsequent transparent conductive film and simplifies the preparation of the transparent conductive film. Of course, it is not limited thereto, and in other embodiments, after the transparent electrode material with a resin layer coated on the surface of the protective layer is formed in step S3 of the above-mentioned transparent electrode material preparation method, the transparent electrode material is separated, and when it is necessary to prepare a conductive ink, the transparent electrode material is dispersed in a water-soluble resin, and other ingredients are added to stir uniformly to form the conductive ink.

[0092] Specifically, the water-soluble resin and the metal nanowire mixed solution are added in a mass ratio of 1: (1.5-2.2), for example, the water-soluble resin and the metal nanowire mixed solution can be added in a mass ratio of 1:1.5, 1:2, 1:2.2, and the like, and the list does not go on and on.

[0093] Specifically, the water-soluble resin includes one or more of water-based polyurethane, water-based polyacrylate, and water-based cellulose resin. Among them, the water-based cellulose can use poly N-vinyl pyrrolidone, or methyl cellulose, or hydroxyethyl cellulose, or carboxymethyl cellulose, etc.

[0094] Further, the present application also provides a transparent conductive film, which includes the above-mentioned transparent electrode material 10; or the transparent conductive film is prepared by using the above-mentioned conductive ink.

[0095] Specifically, the transparent conductive film is prepared by using the above-mentioned conductive ink, and the specific steps are as follows: the conductive ink is coated / spun on the surface of the PET film material, the drying temperature is 50-200℃, such as 100℃, and the transparent conductive film of metal nanowire can be obtained after drying.

[0096] The content of the present application will be described in detail in the following specific example 1 and comparative examples 1-3, wherein the metal nanowire is silver nanowire, the stannous salt solution is T2E (2-ethylhexanoic acid stannous), and the material of the resin layer is copolyester resin; of course, it can be understood that the embodiments of the present application are not limited to these examples.

[0097] Example 1:

[0098] Take 200g of silver nanowire synthesis stock solution as solvent ethylene glycol, that is, silver nanowire solution, wherein the silver nanowire content is 0.5 wt.%;

[0099] Select commercially available T2E (2-ethylhexanoic acid stannous) liquid, disperse in anhydrous ethanol, and prepare a T2E solution with a volume concentration of 0.1 vol.%;

[0100] Measure 200g of T2E solution and add it to the silver nanowire solution, stir on a magnetic stirrer at 30℃ for 30min, to obtain a uniformly mixed system;

[0101] Then measure 6.4ml of deionized water and add it to the mixed system, stir again using a magnetic stirrer for 30min, to make the solution uniformly mixed to form a reaction solution, and then stand at room temperature for 12h, to make the hydrolysis reaction fully proceed;

[0102] After the hydrolysis reaction is completed, the reaction solution is purified by a cross-flow filter, and after purification, the silver nanowires coated with a tin oxide layer are dispersed in deionized water to form a silver nanowire dispersion liquid for standby;

[0103] The copolyester resin is diluted with deionized water to obtain a resin solution with a solid content of 30 wt.%;

[0104] 1 wt.% of the resin solution is added to the silver nanowire dispersion liquid, and stirred on a magnetic stirrer for 2 h to form a silver nanowire mixture liquid, so that the resin is uniformly mixed and coated on the surface of the tin oxide layer;

[0105] Subsequently, water-based cellulose is added to the silver nanowire mixture liquid, wherein the mass ratio of water-based cellulose to silver nanowire mixture liquid is 1:2, and a magnetic stirrer is used for stirring for 30 min, to obtain a conductive ink for coating;

[0106] The conductive ink is coated on a PET film or a glass surface and dried at 100°C to obtain a transparent conductive film A.

[0107] Comparative Example 1:

[0108] 200 g of silver nanowire synthesis stock solution of solvent ethylene glycol, i.e. silver nanowire solution, is weighed, wherein the silver nanowire content is 0.5 wt.%;

[0109] A commercially available T2E (2-ethylhexanoic acid stannous) liquid is selected, dispersed in anhydrous ethanol, and prepared into a T2E solution with a volume concentration of 0.1 vol.%;

[0110] 200 g of T2E solution is measured and added to the silver nanowire solution, stirred on a magnetic stirrer at 30°C for 30 min to obtain a uniformly mixed system;

[0111] Subsequently, 6.4 ml of deionized water is measured and added to the mixed system, and a magnetic stirrer is used again for stirring for 30 min to uniformly mix the solution to form a reaction solution, which is then left to stand at room temperature for 12 h to allow the hydrolysis reaction to proceed fully;

[0112] After the hydrolysis reaction is completed, the reaction solution is purified by a cross-flow filter, and after purification, the silver nanowires coated with a tin oxide layer are dispersed in deionized water to form a silver nanowire dispersion liquid for standby;

[0113] Subsequently, water-based cellulose is added to the silver nanowire dispersion liquid, wherein the mass ratio of water-based cellulose to silver nanowire dispersion liquid is 1:2, and a magnetic stirrer is used for stirring for 30 min, to obtain a conductive ink for coating;

[0114] The conductive ink is coated on a PET film or a glass surface and dried at 100°C to obtain a transparent conductive film B.

[0115] Comparative Example 2:

[0116] 200 g of a silver nanowire synthesis stock solution, i.e., a silver nanowire solution, having a silver nanowire content of 0.5 wt.% was weighed out using ethylene glycol as a solvent, the silver nanowire solution was purified using a cross-flow filter, and after the purification was completed, the silver nanowires were dispersed in deionized water to form a silver nanowire dispersion liquid for standby;

[0117] The copolyester resin was diluted using deionized water to obtain a resin liquid having a solid content of 30 wt.%;

[0118] 1 wt.% of the resin liquid was added to the silver nanowire dispersion liquid, and the mixture was stirred on a magnetic stirrer for 2 h to form a silver nanowire mixture liquid, so that the resin was mixed uniformly and coated on the surface of the silver nanowires;

[0119] Subsequently, water-based cellulose was added to the silver nanowire mixture liquid, the mass ratio of the water-based cellulose to the silver nanowire mixture liquid was 1:2, and the mixture was stirred using a magnetic stirrer for 30 min to obtain a conductive ink for coating;

[0120] The conductive ink was coated on a PET film or a glass surface and dried at 100°C to obtain a transparent conductive film C.

[0121] Comparative Example 3:

[0122] 200 g of a silver nanowire synthesis stock solution, i.e., a silver nanowire solution, having a silver nanowire content of 0.5 wt.% was weighed out using ethylene glycol as a solvent, the silver nanowire solution was purified using a cross-flow filter, and after the purification was completed, the silver nanowires were dispersed in deionized water to form a silver nanowire dispersion liquid for standby;

[0123] Subsequently, water-based cellulose was added to the silver nanowire dispersion liquid, the mass ratio of the water-based cellulose to the silver nanowire dispersion liquid was 1:2, and the mixture was stirred using a magnetic stirrer for 30 min to obtain a conductive ink for coating;

[0124] The conductive ink was coated on a PET film or a glass surface and dried at 100°C to obtain a transparent conductive film D.

[0125] The above-mentioned Example 1 and Comparative Examples 1 to 3 were subjected to performance tests as shown in Table 1 below:

[0126] Table 1

[0127]

[0128] The performance test results of the above-mentioned Example 1 and Comparative Examples 1 to 3 are shown in Table 2 below:

[0129] Table 2

[0130]

[0131] Further combining the above Table 2 and the figures 2(a)~2(d), 3(a)~3(b), it can be seen from the figure 2 that in the comparative example 2 and the comparative example 3, since the silver nanowires are not coated with the tin oxide layer, the silver nanowires after the test are obviously powdered, and the conductivity has completely failed, and the impedance data cannot be detected; and in the example 1 and the comparative example 1, since the tin oxide layer exists, the heat resistance stability of the silver nanowires is significantly improved, the silver nanowires after the test still remain the intact state, and the impedance data also changes less; it can also be obviously seen from the figure 3 that the silver nanowires in the comparative example 3 cannot withstand the high temperature environment, and the silver nanowires at the joint of the multiple silver wires melt and break due to overheating, while the silver nanowires coated with the tin oxide layer in the comparative example 1 remain the intact structure.

[0132] Further combining the above Table 2 and the figures 4(a)~4(b), it can be seen that the transparent conductive film in the comparative example 1 uses the silver nanowires coated with the tin oxide layer, and the width of the silver nanowires corroded on the positive side of the film material channel under the microscope is 33.8 μm, while the transparent conductive film in the comparative example 3 uses the silver nanowires not coated with the tin oxide layer, and the width of the silver nanowires corroded on the positive side of the film material channel under the microscope is 43.77 μm, and it can be seen that the tin oxide layer significantly improves the anodic oxidation resistance of the silver nanowires.

[0133] It can be seen from the above Table 2 that the transparent conductive film formed by the transparent electrode material in the present application, i.e. the transparent conductive film in the example 1, has good heat resistance, oxidation resistance against water and oxygen, anodic oxidation resistance, ink corrosion resistance and good 84 corrosion resistance.

[0134] In summary, the transparent electrode material in the present application coats a protective layer on the surface of the metal nanowires, and coats a resin layer on the surface of the protective layer, on the one hand, the protective layer (tin oxide layer, or silicon oxide layer, or titanium oxide layer) can block the influence of the external environment on the metal nanowires, block the contact of the metal nanowires with the oxygen and water vapor in the external environment, improve the oxidation resistance of the metal nanowires against water and oxygen, and at the same time, improve the heat resistance of the metal nanowires and the anodic oxidation resistance of the metal nanowires when electrified in high temperature and high humidity; on the other hand, the resin layer coated on the periphery of the protective layer can protect the protective layer from chemical corrosion, so that the protective layer can effectively protect the metal nanowires, and at the same time, improve the physical stability and chemical stability of the metal nanowires.

[0135] It should be understood that although the present specification describes only a single embodiment, the disclosure of this specification includes any and all embodiments having any one of the features set forth in the specification and / or attached claims. Moreover, although individual embodiments of this specification can only disclose one independent technical solution, the specification is described in this way only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

[0136] The above detailed description of a series of specific embodiments is merely for the feasibility of the present application, and is not intended to limit the protection scope of the present application. Any equivalent embodiments or changes made without departing from the spirit of the present application shall be included in the protection scope of the present application.

Claims

1. A transparent electrode material, characterized in that: The transparent electrode material includes metal nanowires, a protective layer coated on the surface of the metal nanowires, and a resin layer coated on the surface of the protective layer; the protective layer is a tin oxide layer, a silicon oxide layer, or a titanium oxide layer.

2. The transparent electrode material according to claim 1, wherein: The thickness of the protective layer is 1 nm to 10 nm.

3. The transparent electrode material according to claim 1, wherein: The resin layer is one of polyester resin, epoxy resin and polypropylene resin.

4. A method for preparing the transparent electrode material according to claim 1, characterized in that: The preparation method comprises the following steps: forming a protective layer on the surface of the metal nanowire to form a metal nanowire covered with the protective layer, wherein the protective layer is a tin oxide layer, a silicon oxide layer, or a titanium oxide layer; dispersing the metal nanowires coated with the protective layer in an aqueous solvent to form a metal nanowire dispersion; Resin is added to the metal nanowire dispersion and mixed evenly to form a metal nanowire mixed solution. At the same time, a transparent electrode material with a resin layer coated on the surface of the protective layer is formed.

5. The method for preparing a transparent electrode material according to claim 4, wherein: The content of the resin in the metal nanowire mixture is less than 5 wt.%.

6. The method for preparing a transparent electrode material according to claim 4, wherein: “Adding resin to the metal nanowire dispersion and mixing uniformly to form a metal nanowire mixed solution” specifically includes the following steps: Dissolve the resin in deionized water and dilute it into resin liquid; The resin solution is added to the metal nanowire dispersion and mixed uniformly to form a metal nanowire mixed solution.

7. The method for preparing a transparent electrode material according to claim 6, wherein: The mass concentration of the resin liquid is 28%-35%.

8. The method for preparing a transparent electrode material according to claim 4, wherein: The mass ratio of the metal nanowires to the aqueous solvent in the metal nanowire dispersion is 4%-40%.

9. The method for preparing a transparent electrode material according to claim 4, wherein: The protective layer is a tin oxide layer; and “forming a protective layer on the surface of the metal nanowires” specifically comprises the following steps: obtaining a metal nanowire solution, wherein the metal nanowire solution comprises a non-aqueous solvent and metal nanowires dispersed in the non-aqueous solvent; dispersing a stannous salt in a non-aqueous solvent to form a stannous salt solution; adding the stannous salt solution dropwise to the metal nanowire solution in a predetermined ratio to obtain a mixed system; A preset amount of deionized water is added to the mixed system and mixed evenly to form a reaction solution. At the same time, a protective layer is coated on the surface of the metal nanowires.

10. The method for preparing a transparent electrode material according to claim 9, wherein: The mass concentration of the metal nanowire solution is 0.45 wt.% to 0.52 wt.%.

11. The method for preparing a transparent electrode material according to claim 9, wherein: The volume concentration of the stannous salt solution is 0.08 vol.%-0.13 vol.%.

12. The method for preparing a transparent electrode material according to claim 9, wherein: The mass ratio of the stannous salt solution to the metal nanowire solution is 1-8:

4.

13. The method for preparing a transparent electrode material according to claim 9, wherein: The mass ratio of Sn2+ in the stannous salt solution added to the mixed system to the deionized water added to the mixed system is 0.1% to 5%.

14. The method for preparing a transparent electrode material according to claim 9, wherein: After coating the surface of the metal nanowires with a protective layer, the preparation method further comprises the following steps: The reaction liquid is cleaned and purified by a centrifuge or a cross-flow machine to obtain metal nanowires coated with a protective layer.

15. Use of the transparent electrode material according to any one of claims 1 to 3 in conductive ink or transparent conductive film.

16. Use of the transparent electrode material obtained by the preparation method according to any one of claims 4 to 14 in conductive ink and transparent conductive film.

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