Silver nanowire ink suitable for various printing processes and preparation method and application thereof

Abstract

The invention relates to the technical field of conductive ink, and discloses silver nanowire ink suitable for various printing processes and a preparation method and application thereof. The preparation method comprises the following steps: adding a silver ion-containing solution into a PVP composite solution, uniformly stirring, heating to react, and quickly cooling to room temperature to obtain a silver nanowire stock solution; the preparation method comprises the following steps: dissolving a hyperbranched polymer containing a polar terminal functional group in a solvent to prepare a hyperbranched polymer solution; carrying out purification treatment on the silver nanowire stock solution, and then carrying out concentration treatment to obtain a concentrated solution; adding the hyperbranched polymer solution into the concentrated solution for reaction, and collecting a solid-phase product after the reaction is finished; and dispersing the solid-phase product in an organic solvent to obtain the silver nanowire ink. The silver nanowires in the prepared silver nanowire ink are good in dispersity and high in solid content; the ink still has excellent dispersity and high stability under the condition of high solid content, and can be compatible with various flexible substrates and general printing processes, so that high-precision printing is realized.

Description

Technical Field

[0001] The present application relates to the technical field of conductive inks, and in particular to a silver nanowire ink suitable for a variety of printing processes, and a preparation method and application thereof. Background Art

[0002] Silver nanowires are considered to be the most promising flexible electrode material to replace ITO due to their high conductivity and mechanical flexibility. However, like all nanowire materials with a large aspect ratio, silver nanowires have a high tendency to aggregate in their suspensions, which reduces the conductivity and stability of silver nanowire inks.

[0003] At present, in order to improve the dispersibility of silver nanowires, relevant personnel have conducted extensive research. For example, Chinese patent CN117773095 B discloses a silver nanowire dispersion method based on montmorillonite, which improves the uniformity of montmorillonite's own dispersion and adjusts the pH value of the mixed solution through PVP aqueous solution and carboxylated nanocellulose, avoiding montmorillonite from inducing silver nanowire coagulation due to its own dispersion problem; the modified montmorillonite enhances the steric hindrance and electrostatic steric hindrance between particles in the dispersion liquid, and realizes the effective dispersion and stabilization of silver nanowires. Patent application CN 115862959A discloses a method for improving the photoelectric properties of silver nanowire conductive film, which dissolves the PVP insulating layer coated on the surface of the silver nanowire with a citric acid solution, enhances the conductivity of the silver nanowire, and reduces the aggregation and entanglement between the wires; when the conductive network structure is stable, the citric acid is removed by a high-temperature heat treatment step to avoid the weakening of the electrical properties of the conductive film by the non-conductive citric acid, and at the same time solves the problem that the surface of the silver nanowire is coated with the PVP insulating layer and the silver nanowire has poor dispersibility in the dispersion liquid.

[0004] However, the above methods usually require the addition of a large amount of organic polymer dispersants, such as polyvinyl pyrrolidone, to prevent silver nanowires from agglomerating by forming steric effects or electrical repulsion. These polymers that are tightly adsorbed and wrapped on the nanowires hinder the connection between the nanowires, thereby significantly reducing the conductivity of the printed silver nanowire electrodes; polymer additives can be removed by post-treatment such as solvent washing and high-temperature annealing, but this will increase the complexity of the process and damage the printed pattern and flexible substrate, which is challenging in constructing complex structures with high resolution and assembling large-scale patterns with high uniformity. In addition, the silver nanowire ink prepared by the above method has a low dispersion concentration, and the maximum concentration of the silver nanowire ink in an organic solvent is less than 20 mg / mL, which is difficult to be compatible with various flexible substrates and general printing processes. Summary of the invention

[0005] The present application provides a silver nanowire ink suitable for a variety of printing processes, and a preparation method and application thereof, aiming to solve the technical problems of poor dispersibility, low solid content, large contact resistance of silver nanowire welding points caused by the presence of dispersants, low printing resolution of silver nanowire ink, and difficulty in compatibility with various flexible substrates and general printing processes in existing silver nanowire inks.

[0006] In order to achieve the above objectives, the present application adopts the following technical solutions.

[0007] In a first aspect of the present application, a method for preparing a silver nanowire ink suitable for a variety of printing processes is provided, comprising:

[0008] S1, adding the silver ion solution to the PVP composite solution, stirring evenly and heating to react, and then rapidly cooling to room temperature to obtain a silver nanowire stock solution;

[0009] dissolving a hyperbranched polymer containing polar terminal functional groups in a solvent to prepare a hyperbranched polymer solution;

[0010] S2, purifying the silver nanowire stock solution, and then concentrating it to obtain a concentrated solution;

[0011] S3, adding the hyperbranched polymer solution to the concentrated solution for reaction, collecting the solid phase product after the reaction is completed; dispersing the solid phase product in an organic solvent to obtain silver nanowire ink.

[0012] Preferably, the polar terminal functional groups of the hyperbranched polymer containing polar terminal functional groups include any one of carboxyl, sulfonic acid, phosphoric acid, thiol, carbonyl, primary amine, secondary amine and tertiary amine.

[0013] Preferably, the chemical structure of the hyperbranched polymer containing polar terminal functional groups is as shown in formula (1) or formula (2):

[0014]

[0015] Preferably, the silver ion solution is an ethylene glycol solution of silver nitrate, and its concentration is 0.04-0.1 g / mL.

[0016] Preferably, the PVP composite solution is prepared by the following method:

[0017] Prepare a PVP ethylene glycol solution and a sodium chloride ethylene glycol solution respectively; add the sodium chloride ethylene glycol solution to the PVP ethylene glycol solution and mix well to obtain;

[0018] Among them, the PVP concentration is 0.01-0.02 g / mL, and the sodium chloride concentration is 7-8 mM.

[0019] Preferably, in the concentrated solution, the concentration of silver nanowires is 0.1 to 5 mg / mL;

[0020] and / or,

[0021] The amount of the hyperbranched polymer containing polar terminal functional groups is 0.01 to 20 wt % of the amount of the silver nanowires.

[0022] Preferably, the reaction temperature in S1 is 90 to 150°C;

[0023] and / or,

[0024] In S2, the purification treatment shown includes filtration, centrifugation or ion exchange.

[0025] Preferably, the organic solvent includes one or a mixture of two or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, isopropyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide.

[0026] In a second aspect of the present application, there is provided a silver nanowire ink prepared by the above preparation method and suitable for a variety of printing processes, wherein the silver nanowire content in the silver nanowire ink is 0.01 to 30 wt %.

[0027] The third aspect of the present application provides the application of the above-mentioned silver nanowire ink suitable for various printing processes in the fields of microelectronics, solar cells, and flexible electronics.

[0028] Compared with the prior art, the beneficial effects of this application are:

[0029] The silver nanowire ink prepared in the present application uses hyperbranched polymers instead of dispersants, stabilizers, and rheology modifiers, and no other additives are required; the low additive content allows the silver nanowire ink of the present application to maintain high conductivity. Among them, the hyperbranched polymer coordinates or adsorbs on the surface of the silver nanowires with the polar end functional groups (anchoring groups) and silver atoms / silver ions on the surface of the silver nanowires, and induces spatial stability through the interaction between the solvated chains and the solvent, so that the silver nanowires are evenly dispersed in the organic solvent; through the disentanglement of the hyperbranched polymer molecular chains, the viscosity and rheological properties of the silver nanowire ink are regulated, so that the silver nanowire ink of the present application still has excellent dispersibility and high stability at high solid content, and it is compatible with various flexible substrates and general printing processes to achieve high-precision printing.

[0030] In the silver nanowire ink prepared in the present application, the content of silver nanowires can reach up to 200 mg / mL, the contact resistance of the welding point is low, the printing resolution is high, and the applicability is wide; it can be printed on different substrates by screen printing, slit coating, rod coating, and extrusion 3D printing technology, and then high-conductivity optical / electrical devices can be prepared by low-temperature sintering, which can be used in microelectronics, solar cells, flexible electronics and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a SEM image of the silver nanowires in the silver nanowire dispersion prepared in Example 1;

[0033] Figure 2 This is a physical picture of silver nanowire / isopropanol ink with a concentration of 10 mg / mL;

[0034] Figure 3 This is a physical picture of a flexible silver nanowire transparent electrode prepared by a rod coating process using silver nanowire / isopropyl alcohol ink with a concentration of 10 mg / mL and a PET substrate;

[0035] Figure 4 This is a physical picture of silver nanowire / isopropyl alcohol ink with a concentration of 60 mg / mL;

[0036] Figure 5 This is a physical picture of a flexible silver nanowire electrode prepared by a slit printing process using silver nanowire / isopropyl alcohol ink with a concentration of 60 mg / mL and a PET substrate;

[0037] Figure 6 This is a physical picture of silver nanowire / isopropyl alcohol ink with a concentration of 120 mg / mL;

[0038] Figure 7 This is a physical picture of a silver nanowire flexible coil prepared by screen printing process using silver nanowire / isopropyl alcohol ink with a concentration of 120 mg / mL and a paper substrate;

[0039] Figure 8 This is a physical picture of silver nanowire / isopropyl alcohol ink with a concentration of 200 mg / mL;

[0040] Fig. 9A physical picture of a silver nanowire stretchable electrode prepared by extrusion 3D printing process using silver nanowire / isopropanol ink with a concentration of 200 mg / mL and PDMS substrate;

[0041] Fig.10 This is a physical picture of silver nanowire / ethanol ink with a concentration of 200 mg / mL;

[0042] Fig.11 This is a physical picture of silver nanowire / N,N-dimethylformamide ink with a concentration of 60 mg / mL;

[0043] Fig.12 This is a physical picture of silver nanowire / N-methylpyrrolidone ink with a concentration of 60 mg / mL;

[0044] Fig.13 This is a physical picture of silver nanowire / dimethyl sulfoxide ink with a concentration of 60 mg / mL. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are all open terms, meaning including but not limited to.

[0047] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0048] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0049] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0050] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0051] Those skilled in the art will appreciate that the numerical ranges in the embodiments of the present application are to be construed as specifically disclosing each intermediate value between the upper and lower limits of the scope. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0052] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0053] In a first aspect, the present application provides a method for preparing a silver nanowire ink suitable for a variety of printing processes, comprising:

[0054] S1, adding the silver ion solution to the PVP composite solution, stirring evenly, heating to 90-150° C. for reaction, and then rapidly cooling to room temperature to obtain a silver nanowire stock solution;

[0055] dissolving a hyperbranched polymer containing polar terminal functional groups in a solvent to prepare a hyperbranched polymer solution;

[0056] In the present application, the silver ion solution is an ethylene glycol solution of silver nitrate, and its concentration is 0.04-0.1 g / mL;

[0057] In this application, the PVP composite solution is prepared by the following method:

[0058] Prepare respectively a PVP ethylene glycol solution with a concentration of 0.01 to 0.02 g / mL and a sodium chloride ethylene glycol solution with a concentration of 7 to 8 mM;

[0059] Add the ethylene glycol solution of sodium chloride to the ethylene glycol solution of PVP and mix well to obtain the product.

[0060] In the present application, the volume ratio of the ethylene glycol solution of silver nitrate, the ethylene glycol solution of PVP and the ethylene glycol solution of sodium chloride is preferably 1:4:(0.25-0.75).

[0061] In the present application, the end groups of the hyperbranched polymer are polar functional groups, such as any one of carboxyl, sulfonic acid, phosphoric acid, thiol, carbonyl, primary amine, secondary amine, tertiary amine and the like, preferably primary amine or thiol.

[0062] As a preferred embodiment, the hyperbranched polymer of the present application includes any one of the following chemical structures:

[0063]

[0064]

[0065] S2, purifying the silver nanowire stock solution, and then concentrating it to obtain a concentrated solution;

[0066] In the present application, impurities such as silver nanoparticles, silver nanorods, silver nano / micron sheets, polyvinyl pyrrolidone (PVP), ferric chloride, ferrous chloride, silver nitrate and silver chloride are removed from the silver nanowire stock solution by centrifugation or filtration to improve the purity of the silver nanowire stock solution. The present application preferably uses the stirring induced centrifugal force-vertical filtration purification device disclosed in the Chinese patent (ZL202221176878.7) to purify with ethanol. After purification, the concentration of the silver nanowire stock solution is concentrated to 0.1-5 mg / mL.

[0067] S3, adding the hyperbranched polymer solution to the concentrated solution for reaction, the reaction time is 5-60 minutes; after the reaction is completed, collecting the solid phase product; dispersing the solid phase product in an organic solvent to obtain silver nanowire ink.

[0068] In the present application, the amount of the hyperbranched polymer containing polar terminal functional groups is preferably 0.01 to 20 wt % of the amount of the silver nanowires. After the reaction is completed, the supernatant is removed by centrifugation to collect the solid precipitate.

[0069] In the present application, the organic solvent can be selected from one or a mixture of two or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, isopropyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide.

[0070] The silver nanowire ink prepared in the present application uses a hyperbranched polymer to replace a dispersant, a stabilizer, and a rheology modifier, and does not require other additives; the low additive content enables the silver nanowire ink of the present application to maintain high conductivity.

[0071] The silver nanowire ink prepared in the present application, wherein the hyperbranched polymer coordinates or adsorbs on the surface of the silver nanowire with the polar terminal functional groups (anchoring groups) and the silver atoms / silver ions on the surface of the silver nanowires, and induces spatial stability through the interaction between the solvated chains and the solvent, so that the silver nanowires are evenly dispersed in the organic solvent; the viscosity and rheological properties of the silver nanowire ink are regulated by the disentanglement of the hyperbranched polymer molecular chains, so that the silver nanowire ink of the present application still has excellent dispersibility and high stability at a high solid content, and is compatible with various flexible substrates and general printing processes to achieve high-precision printing.

[0072] The silver nanowire ink of the present application has a silver nanowire content of 0.01 to 30 wt % and a viscosity of 0.01 to 10000 Pa·s; wherein the silver nanowire has a diameter of 20 to 100 nm and a length of 10 to 200 μm.

[0073] The silver nanowire content of the present application can reach up to 200 mg / mL, the contact resistance of the welding point is low, the printing resolution is high, and the applicability is wide. It can be printed on different substrates by screen printing, slit coating, rod coating, and extrusion 3D printing technology. High-conductivity flexible transparent optoelectronic devices or conventional electronic components such as flexible transparent electrodes, electrode wires, current collectors, connection points, etc. can be prepared by low-temperature sintering. It can be used in microelectronics, solar cells, flexible electronics and other fields, such as traditional electronic circuit boards, printed circuits, silicon-based solar cell electrode plates, electromagnetic shielding, flexible electronics, printed electronics, wearable electronics, etc.

[0074] The present application is further described below by way of examples.

[0075] In the examples of the present application, the amino-terminated hyperbranched polymer is prepared by the method disclosed in the document ACSStain.Chem.Eng.5, 10258-10265 (2017), and its chemical structure is:

[0076]

[0077] In the embodiments of the present application, the thiol-terminated hyperbranched polymer is prepared by the method disclosed in Prog.Org.Coat.139,105436 (2020), and its chemical structure is:

[0078]

[0079] Example 1

[0080] This embodiment provides a method for preparing silver nanowire ink, comprising:

[0081] S1, weigh 2 g of AgNO3 and place it in a brown round-bottom flask, add 40 mL of ethylene glycol, and stir magnetically for 0.5 h until the AgNO3 is completely dissolved to obtain an AgNO3 solution;

[0082] Weigh 2 g of PVP into a brown round-bottom flask, add 160 ml of ethylene glycol, heat and stir under magnetic stirring for 3 h until the PVP is completely dissolved; add 16.32 mL of 7.2 mM NaCl / ethylene glycol solution, stir for 5 min, mix well, and cool to room temperature to obtain a PVP composite solution;

[0083] 20 mg of the amino-terminated hyperbranched polymer was weighed and dissolved in 20 mL of ethanol to prepare an amino-terminated hyperbranched polymer / ethanol solution with a concentration of 1 mg / mL.

[0084] S2, under magnetic stirring, adding the AgNO3 solution to the PVP composite solution, stirring for 10 minutes to make it evenly mixed; heating the mixed solution in a blast oven at 110°C for 12 hours, and after the reaction is completed, quickly cooling it to room temperature in a cold water bath to obtain a silver nanowire stock solution;

[0085] The silver nanowire stock solution is purified by ethanol through a stirring-induced centrifugal force-vertical filtration purification device of the authorized patent (ZL202221176878.7) to remove impurities; after 200 minutes of filtration and purification, the ethanol is stopped from being added, and stirring and filtering are maintained until the concentration of the silver nanowire dispersion is 1 mg / mL, and stirring is stopped and the product is received from the discharge pipe at the base of the internal cavity;

[0086] S3, taking 10 mL of 1 mg / mL silver nanowire dispersion, adding 10 μL of 1 mg / mL amino-terminated hyperbranched polymer / ethanol solution, mixing, reacting for 15 min, and collecting the precipitate by centrifugation; dispersing the precipitate in 1 mL of isopropanol to obtain a 10 mg / mL silver nanowire / isopropanol ink with a silver nanowire content of 1.2 wt%.

[0087] Example 2

[0088] This embodiment provides a method for preparing silver nanowire ink, comprising:

[0089] S1, same as in Example 1;

[0090] S2, same as in Example 1;

[0091] S3, taking 60 mL of 1 mg / mL silver nanowire dispersion, adding 60 μL of 1 mg / mL amino-terminated hyperbranched polymer / ethanol solution, mixing, reacting for 15 min, and collecting the precipitate by centrifugation; dispersing the precipitate in 1 mL of isopropanol to obtain 60 mg / mL silver nanowire / isopropanol ink, wherein the silver nanowire content is 7.1 wt%.

[0092] Example 3

[0093] This embodiment provides a method for preparing silver nanowire ink, comprising:

[0094] S1, same as in Example 1;

[0095] S2, same as in Example 1;

[0096] S3, taking 120mL of 1mg / mL silver nanowire dispersion, adding 120μL of 1mg / mL amino-terminated hyperbranched polymer / ethanol solution, mixing, reacting for 15min, and collecting the precipitate by centrifugation; dispersing the precipitate in 1mL of isopropanol to obtain 120mg / mL silver nanowire / isopropanol ink, wherein the silver nanowire content is 13.2wt%.

[0097] Example 4

[0098] This embodiment provides a method for preparing silver nanowire ink, comprising:

[0099] S1, same as in Example 1;

[0100] S2, same as in Example 1;

[0101] S3, taking 200 mL of 1 mg / mL silver nanowire dispersion, adding 200 μL of 1 mg / mL amino-terminated hyperbranched polymer / ethanol solution, mixing, reacting for 15 min, and collecting the precipitate by centrifugation; dispersing the precipitate in 1 mL of isopropanol to obtain a 200 mg / mL silver nanowire / isopropanol ink with a silver nanowire content of 20.3 wt%.

[0102] Example 5

[0103] This embodiment provides a method for preparing silver nanowire ink, comprising:

[0104] S1, same as in Example 1;

[0105] S2, same as in Example 1;

[0106] S3, taking 200 mL of 1 mg / mL silver nanowire dispersion, adding 200 μL of 1 mg / mL amino-terminated hyperbranched polymer / ethanol solution, mixing, reacting for 15 min, and collecting the precipitate by centrifugation; dispersing the precipitate in 1 mL of ethanol to obtain 200 mg / mL silver nanowire / ethanol ink, wherein the silver nanowire content is 20.2 wt%.

[0107] Example 6

[0108] This embodiment provides a method for preparing silver nanowire ink, comprising:

[0109] S1, weigh 2 g of AgNO3 and place it in a brown round-bottom flask, add 40 mL of ethylene glycol, and stir magnetically for 0.5 h until the AgNO3 is completely dissolved to obtain an AgNO3 solution;

[0110] Weigh 2 g of PVP into a brown round-bottom flask, add 160 ml of ethylene glycol, heat and stir under magnetic stirring for 3 h until the PVP is completely dissolved; add 16.32 mL of 7.2 mM NaCl / ethylene glycol solution, stir for 5 min, mix well, and cool to room temperature to obtain a PVP composite solution;

[0111] 20 mg of the thiol-terminated hyperbranched polymer was weighed and dissolved in 20 mL of ethanol to prepare an amino-terminated hyperbranched polymer / ethanol solution with a concentration of 1 mg / mL.

[0112] S2, same as in Example 1;

[0113] S3, taking 60 mL of 1 mg / mL silver nanowire dispersion, adding 60 μL of 1 mg / mL terminal thiol hyperbranched polymer / ethanol solution, mixing and reacting for 15 minutes, and collecting the precipitate by centrifugation; dispersing the precipitate in 1 mL of N,N-dimethylformamide to obtain a 60 mg / mL silver nanowire / N,N-dimethylformamide ink with a silver nanowire content of 6.0 wt%.

[0114] Example 7

[0115] S1, same as in Example 6;

[0116] S2, same as in Example 6;

[0117] S3, which differs from Example 6 in that the solvent is replaced by N-methylpyrrolidone from N,N-dimethylformamide, and the rest is the same as Example 6. Example 7 obtains a silver nanowire / N-methylpyrrolidone ink with a concentration of 60 mg / mL and a silver nanowire content of 5.5 wt%.

[0118] Example 8

[0119] S1, same as in Example 6;

[0120] S2, same as in Example 6;

[0121] S3, which differs from Example 6 in that the solvent is replaced by dimethyl sulfoxide from N,N-dimethylformamide, and the rest is the same as Example 6. Example 8 obtains a silver nanowire / dimethyl sulfoxide ink with a concentration of 60 mg / mL and a silver nanowire content of 5.2 wt%.

[0122] Example 9

[0123] S1, the difference from Example 1 is that the amount of AgNO3 is 4g, the amount of PVP is 3.2g, and the rest is the same as Example 1;

[0124] S2, same as in Example 1;

[0125] S3, same as Example 1.

[0126] Example 10

[0127] S1, same as in Example 1;

[0128] S2, same as in Example 1;

[0129] S3, the difference from Example 1 is that the amount of the amino-terminated hyperbranched polymer / ethanol solution used is 300 μL, and the rest is the same as Example 1.

[0130] The silver nanowire dispersion prepared in Example 1 was dried on a test bench and then subjected to SEM testing. The SEM image is shown in FIG. Figure 1 As shown. Figure 1 It can be seen that the diameter of the silver nanowire is 20 to 100 nm and the length is 10 to 200 μm.

[0131] Example 1 prepared silver nanowire / isopropanol ink with a concentration of 10 mg / mL, the actual picture is as follows Figure 2 As shown. Figure 2 It can be seen that the silver nanowires are uniformly dispersed in the isopropanol, and the color of the ink is uniform silver-gray, achieving stable dispersion of the silver nanowires in the isopropanol.

[0132] The silver nanowire / isopropanol ink with a concentration of 10 mg / mL prepared in Example 1 was printed on a PET substrate by a rod coating process and sintered at 90° C. for 10 min to obtain a flexible silver nanowire transparent electrode, such as Figure 3 As shown, it is 50cm long and 30cm wide.

[0133] Example 2 prepared silver nanowire / isopropanol ink with a concentration of 60 mg / mL, the actual picture is as follows Figure 4 As shown. Figure 4It can be seen that the silver nanowires are uniformly dispersed in isopropyl alcohol, the color of the ink is uniform silver-gray and presents a colloidal state, and stable dispersion of high-concentration silver nanowires in isopropyl alcohol is achieved.

[0134] The silver nanowire / isopropanol ink with a concentration of 60 mg / mL prepared in Example 2 was printed on a PET substrate by a slit printing process and sintered at 90° C. for 10 min to obtain a flexible silver nanowire electrode. Figure 5 As shown, it is 25cm long and 20cm wide.

[0135] Example 3 prepared silver nanowire / isopropanol ink with a concentration of 120 mg / mL, the actual picture is as follows Figure 6 As shown. Figure 6 It can be seen that the silver nanowires are uniformly dispersed in isopropyl alcohol, the color of the ink is uniform silver-gray and presents a colloidal state, and stable dispersion of high-concentration silver nanowires in isopropyl alcohol is achieved.

[0136] The silver nanowire / isopropanol ink with a concentration of 120 mg / mL prepared in Example 3 was printed on a paper substrate by screen printing and sintered at 90° C. for 10 min to obtain a silver nanowire flexible coil. Figure 7 It is 6 cm long and 5 cm wide, and consists of 10 turns of coils with a wire width of 250 μm and a coil spacing of 250 μm.

[0137] Example 4 prepared a silver nanowire / isopropanol ink with a concentration of 200 mg / mL, as shown in the figure Figure 8 As shown. Figure 8 It can be seen that the silver nanowires are uniformly dispersed in isopropyl alcohol, the color of the ink is uniform silver-gray and presents a colloidal state, and stable dispersion of high-concentration silver nanowires in isopropyl alcohol is achieved.

[0138] The silver nanowire / isopropanol ink with a concentration of 200 mg / mL prepared in Example 4 was printed on a PDMS substrate by an extrusion 3D printing process and sintered at 90° C. for 10 min to obtain a silver nanowire stretchable electrode, such as Fig. 9 As shown, the electrode line width is 250 μm.

[0139] Example 5 prepared a silver nanowire / ethanol ink with a concentration of 200 mg / mL, as shown in the figure Fig.10 As shown. Fig.10 It can be seen that the silver nanowires are uniformly dispersed in ethanol, and the color of the ink is uniform silver-gray, achieving stable dispersion of high-concentration silver nanowires in ethanol.

[0140] Example 6: Silver nanowire / N,N-dimethylformamide ink with a concentration of 60 mg / mL, as shown in the figure Fig.11 As shown. Fig.11 It can be seen that the silver nanowires are uniformly dispersed in N,N-dimethylformamide, and the color of the ink is uniform silver-gray, achieving stable dispersion of high-concentration silver nanowires in N,N-dimethylformamide.

[0141] Example 7: Silver nanowire / N-methylpyrrolidone ink with a concentration of 60 mg / mL, as shown in the figure Fig.12 As shown. Fig.12 It can be seen that the silver nanowires are uniformly dispersed in N-methylpyrrolidone, and the color of the ink is uniform silver-gray, achieving stable dispersion of high-concentration silver nanowires in N-methylpyrrolidone.

[0142] Example 8 prepared a silver nanowire / dimethyl sulfoxide ink with a concentration of 60 mg / mL, as shown in the figure Fig.13 As shown. Fig.13 It can be seen that the silver nanowires are uniformly dispersed in dimethyl sulfoxide, and the color of the ink is uniform silver-gray, achieving stable dispersion of high-concentration silver nanowires in dimethyl sulfoxide.

[0143] The silver nanowire / isopropyl alcohol inks prepared in Examples 9 and 10 also achieved stable dispersion of the silver nanowires in isopropyl alcohol.

[0144] The above shows that the silver nanowire ink prepared in the present application still has excellent dispersibility and high stability at a high solid content, is compatible with various flexible substrates and general printing processes, and can achieve high-precision printing.

[0145] Although the present application has been described in detail in general terms and in specific embodiments in this specification, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in the present application.

Claims

1. A method for preparing silver nanowire ink suitable for various printing processes, characterized in that: include: S1, adding the silver ion solution to the PVP composite solution, stirring evenly and heating to react, and then rapidly cooling to room temperature to obtain a silver nanowire stock solution; dissolving a hyperbranched polymer containing polar terminal functional groups in a solvent to prepare a hyperbranched polymer solution; S2, purifying the silver nanowire stock solution, and then concentrating it to obtain a concentrated solution; S3, adding the hyperbranched polymer solution to the concentrated solution for reaction, collecting the solid phase product after the reaction is completed; dispersing the solid phase product in an organic solvent to obtain silver nanowire ink.

2. The preparation method according to claim 1, characterized in that: The polar terminal functional group of the hyperbranched polymer containing polar terminal functional groups includes any one of carboxyl, sulfonic acid, phosphoric acid, thiol, carbonyl, primary amine, secondary amine and tertiary amine.

3. The preparation method according to claim 2, characterized in that: The chemical structure of the hyperbranched polymer containing polar terminal functional groups is shown in formula (1) or formula (2):

4. The preparation method according to claim 1, characterized in that: The silver ion solution is an ethylene glycol solution of silver nitrate, and its concentration is 0.04-0.1 g / mL.

5. The preparation method according to claim 1, characterized in that: The PVP composite solution is prepared by the following method: Prepare a PVP ethylene glycol solution and a sodium chloride ethylene glycol solution respectively; add the sodium chloride ethylene glycol solution to the PVP ethylene glycol solution and mix well to obtain; Among them, the PVP concentration is 0.01-0.02 g / mL, and the sodium chloride concentration is 7-8 mM.

6. The preparation method according to claim 1, characterized in that: In the concentrated solution, the concentration of silver nanowires is 0.1 to 5 mg / mL; and / or, The amount of the hyperbranched polymer containing polar terminal functional groups is 0.01 to 20 wt % of the amount of the silver nanowires.

7. The preparation method according to claim 1, characterized in that: The reaction temperature in S1 is 90-150°C; and / or, In S2, the purification treatment shown includes filtration, centrifugation or ion exchange.

8. The preparation method according to claim 1, characterized in that: The organic solvent includes one or a mixture of two or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, isopropyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide.

9. The silver nanowire ink suitable for various printing processes prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The silver nanowire ink contains 0.01 to 30 wt % of silver nanowires.

10. Use of the silver nanowire ink suitable for various printing processes as claimed in claim 9 in the fields of microelectronics, solar cells and flexible electronics.

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