Conductive paste and method for preparing the same

Abstract

This application relates to the field of electronic paste technology, and provides a conductive paste and its preparation method. The conductive paste comprises: 60-85 parts copper powder, 0.1-5 parts photothermal conversion aid, 0.5-3 parts ligand dispersant, 0.1-2 parts antioxidant aid, and 10.5-28 parts organic carrier. In the conductive paste provided by this application, copper powder serves as the conductive phase, forming a conductive network after sintering; the photothermal conversion aid efficiently absorbs light energy and converts it into heat energy, reducing sintering conditions and making the paste compatible with flexible substrates; the ligand dispersant improves the dispersibility of each component, helping to obtain a uniform and stable conductive film layer; the antioxidant aid forms a protective layer on the surface of the copper powder, providing dynamic antioxidant protection and enabling air sintering; the organic carrier imparts good rheological properties to the paste, facilitating uniform film formation. Therefore, with the synergistic effect of each component, it can be efficiently sintered at low temperature and in air environment to obtain a highly dense, highly conductive, and highly stable copper-based film layer.

Description

Technical Field

[0001] This application belongs to the field of electronic paste technology, and in particular relates to a conductive paste and its preparation method. Background Technology

[0002] Printed electronics technology, as a key approach to manufacturing electronic devices, heavily relies on high-performance conductive pastes for its development. Currently, commonly used silver-based conductive pastes possess excellent conductivity and chemical stability, enabling the formation of high-conductivity conductive films at relatively low sintering temperatures. However, silver, as a precious metal, is expensive and its price fluctuates greatly, hindering the large-scale commercial application of printed electronics in cost-sensitive fields such as flexible displays and wearable electronics.

[0003] Copper-based conductive pastes are considered the most promising alternative material due to the low cost and high conductivity of copper. However, their practical application faces two major bottlenecks: First, they are easily oxidized. Copper particles readily oxidize in air to form non-conductive copper oxide or cuprous oxide, which increases the resistivity of the sintered conductive film and may even cause it to lose its conductivity. Therefore, traditional copper-based conductive pastes require sintering in a protective or reducing atmosphere, increasing process complexity and equipment costs. Second, they require high sintering temperatures. Traditional copper-based conductive pastes require high-temperature heat treatment exceeding 200°C or even 300°C to achieve densification and obtain good conductivity. However, this is incompatible with the heat-resistant substrates of flexible electronic devices, easily leading to substrate deformation and degradation, thus limiting their application in the field of flexible electronics.

[0004] Although photo-sintering technology, which uses pulsed or continuous light to irradiate the paste layer and achieves sintering by locally heating the conductive particles through photothermal effects, can effectively reduce the sintering temperature, traditional copper-based conductive pastes have low light absorption efficiency. This necessitates high-energy-density light sources to achieve densification, resulting in high energy consumption and the risk of damaging the substrate. Furthermore, photo-sintering in air accelerates the oxidation of copper particles under photothermal effects, leading to performance degradation. Therefore, photo-sintering technology also cannot achieve efficient sintering of traditional copper-based conductive pastes at low temperatures in air environments to obtain highly conductive and stable films.

[0005] Given the aforementioned shortcomings of traditional silver-based and copper-based conductive pastes, there is an urgent need in the field to develop a novel conductive paste that can achieve rapid sintering at low temperatures and in air, forming a highly dense, highly conductive, and highly stable film. Summary of the Invention

[0006] The purpose of this application is to provide a conductive paste and its preparation method, which aims to solve the problem that traditional copper-based conductive pastes cannot achieve efficient sintering in low temperature and air environment to obtain a highly dense, highly conductive and highly stable film.

[0007] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0008] In a first aspect, this application provides a conductive paste comprising the following components in parts by weight: 60-85 parts copper powder, 0.1-5 parts photothermal conversion aid, 0.5-3 parts ligand dispersant, 0.1-2 parts antioxidant aid, and 10.5-28 parts organic carrier.

[0009] Secondly, this application provides a method for preparing a conductive paste, comprising the following steps:

[0010] The copper powder is coated with the antioxidant to obtain modified copper powder;

[0011] The modified copper powder, the photothermal conversion aid, the ligand dispersant, and the organic carrier are mixed to obtain a conductive slurry.

[0012] Compared with the prior art, this application has the following beneficial effects:

[0013] The conductive paste provided in the first aspect of this application incorporates copper powder as a conductive phase, which forms a conductive network after sintering. The added photothermal conversion aid efficiently absorbs light energy and converts it into heat energy, reducing the sintering temperature, energy input, and sintering time required for copper powder densification, thus endowing the paste with low-temperature sintering characteristics and compatibility with flexible substrates. The added ligand dispersant improves the dispersibility of copper powder and other functional components, ensuring uniform photothermal conversion and efficient heat transfer, contributing to the formation of a conductive film layer with uniform resistance and stable performance. The added antioxidant aid forms a stable protective layer on the surface of the copper powder and provides dynamic antioxidant protection during sintering, enabling the conductive paste to sinter in air. The added organic carrier imparts good rheological properties to the paste, facilitating printing or coating to form a uniform film layer. Therefore, the conductive paste of this application, through the synergistic effect of the photothermal conversion aid, ligand dispersant, and antioxidant aid, can achieve efficient sintering in a low-temperature, air environment, obtaining a highly dense, highly conductive, and highly stable copper-based film layer.

[0014] The second aspect of this application provides a method for preparing conductive paste, which first coats copper powder with an antioxidant to form a protective layer on the surface of the copper powder, thereby providing dynamic antioxidant protection during sintering and enabling air sintering. Then, the modified copper powder, photothermal conversion aid, ligand dispersant and organic carrier are mixed to make the components highly uniformly distributed, so that the prepared conductive paste can achieve efficient photothermal conversion and heat transfer during photo-sintering, providing a guarantee for rapid densification sintering in a low temperature and air environment. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating the preparation method of the conductive paste provided in the embodiments of this application. Detailed Implementation

[0017] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] The first aspect of this application provides a conductive paste comprising the following components in parts by weight: 60-85 parts copper powder, 0.1-5 parts photothermal conversion aid, 0.5-3 parts ligand dispersant, 0.1-2 parts antioxidant aid, and 10.5-28 parts organic carrier.

[0019] The conductive paste provided in this application uses copper powder as a conductive phase, which can form a conductive network after sintering. The added photothermal conversion aid efficiently absorbs light energy and converts it into heat energy, reducing the sintering temperature, energy input, and sintering time required for copper powder densification, thus endowing the paste with low-temperature sintering characteristics and compatibility with flexible substrates. The added ligand dispersant improves the dispersibility of copper powder and other functional components, ensuring uniform photothermal conversion and efficient heat transfer, which helps to obtain a conductive film layer with uniform resistance and stable performance. The added antioxidant aid forms a stable protective layer on the surface of the copper powder and provides dynamic antioxidant protection during sintering, enabling the conductive paste to sinter in air. The added organic carrier imparts good rheological properties to the paste, facilitating printing or coating to form a uniform film layer. Therefore, the conductive paste of this application, under the synergistic effect of the photothermal conversion aid, ligand dispersant, and antioxidant aid, can achieve efficient sintering in a low-temperature, air environment, and obtain a copper-based film layer with high density, high conductivity, and high stability.

[0020] In a preferred embodiment, the conductive paste comprises: 70-80 parts copper powder, 0.5-2 parts photothermal conversion aid, 1-2 parts ligand dispersant, 0.2-1 parts antioxidant aid, and 13-20 parts organic carrier.

[0021] In the embodiments, the particle size of the copper powder is 10~300 nm. Further, the particle size of the nano-copper powder is 50~150 nm. Controlling the particle size of the nano-copper powder within the range of this embodiment can significantly improve the sintering activity of the copper powder, enabling densification sintering at lower photothermal energy. It also helps maintain good dispersion stability in the slurry, avoids deposition, and improves the uniformity of the printed film. In the embodiments, the photothermal conversion aid includes acetylene black, titanium nitride nanoparticles, and carbon quantum dots in a mass ratio of (4.5~5.5):(1.5~2.5):(0.5~1.5). Acetylene black has the characteristic of efficiently absorbing ultraviolet to near-infrared light and converting it into heat energy. As the main heat source, it rapidly heats up, providing a basic heat source for the photothermal conversion system. Furthermore, its chain-like or grape-like structure has an extremely high specific surface area, which can form a three-dimensional continuous network framework between copper particles, achieving rapid heat conduction and providing photothermal conversion. Titanium nitride nanoparticles possess a unique localized surface plasmon resonance (LSPR) effect. Under light irradiation, they generate a strong localized electromagnetic field enhancement and heat accumulation, forming hotspots. These hotspots precisely act on the oxide layer and sintering neck of the copper particles, providing instantaneous localized high temperatures to break down oxide barriers, activate copper particle surface atoms, and lower the sintering initiation energy barrier. Carbon quantum dots, with their extremely small size and rich surface functional groups, are uniformly adsorbed at the interface of acetylene black, titanium nitride nanoparticles, and copper particles, acting as a "molecular glue" to improve the compatibility and thermal contact between the components. Simultaneously, they exert a catalytic effect during the photothermal process, promoting rapid diffusion and fusion of copper particles at lower temperatures. Therefore, this embodiment, with a specific ratio of the three components, achieves higher efficiency and more compact sintering under lower light energy density (lower temperature) conditions through the synergistic effect of macroscopic heating, microscopic activation, and interface optimization.

[0022] In the embodiments, the ligand dispersant is selected from one or more of ethanolamine, formamide, and imine compounds. The imine compounds can be selected from aldehyde imines, ketoimines, polyethyleneimines, polyimides, etc. These ligand dispersant molecules contain functional groups such as amino and imino groups, which can form coordination interactions with the copper powder surface, effectively improving the dispersibility of copper powder in the organic carrier and preventing agglomeration.

[0023] In the embodiments, the antioxidant auxiliaries include imidazole phosphate and triethylphosphonate in a mass ratio of (2~4):(0.5~1.5).

[0024] In the embodiments, the organic carrier includes: 0.2 to 1 part of film-forming aid, 0.2 to 1.5 parts of binder, 0.1 to 0.5 parts of reducing resin, and 10 to 25 parts of solvent.

[0025] In a preferred embodiment, the film-forming aid is 0.3 to 0.6 parts, the binder is 0.5 to 1 part, the reducing resin is 0.2 to 0.4 parts, and the solvent is 12 to 18 parts.

[0026] In the embodiments, the film-forming aid is selected from one or more of polyurethane, ethylene carbonate, and hydroxyethyl cellulose. Adding these film-forming aids ensures that the slurry forms a film layer with good continuity and strong adhesion to the substrate after coating, printing, and drying processes.

[0027] In the embodiments, the binder is selected from one or more of carboxymethyl cellulose, acrylic resin, and polyvinyl butyral. Adding these binders ensures that the slurry forms a film with good continuity and strong adhesion to the substrate after coating, printing, and drying processes.

[0028] In the embodiments, the reducing resin is selected from one or more of polyvinyl alcohol, polyvinylpyrrolidone, and copolymers of styrene and divinylbenzene. The addition of these reducing resins allows for the decomposition and generation of a reducing atmosphere during high-temperature sintering, and forms a dual protection with the antioxidant, enabling the slurry to sinter in air to form a highly dense, highly conductive, and highly stable film.

[0029] In the examples, the solvent is selected from one or more of ethylene glycol phenyl ether, terpineol, and polyethylene glycol.

[0030] In the embodiment, the conductive paste is coated or printed, dried, and sintered to form a conductive film with a thickness of 10 μm. The sheet resistance of the conductive film is ≤20 mΩ / □. The conductive film is placed in an air environment with a temperature of 25±5℃ and a relative humidity of 40~60% for 48 hours and the resistance change rate of the conductive film is ≤10%.

[0031] The conductive paste of the above embodiments can be prepared by the following preparation method.

[0032] The second aspect of this application provides a method for preparing a conductive paste, such as... Figure 1 As shown, it includes the following steps:

[0033] S1: Coating copper powder with antioxidants yields modified copper powder;

[0034] S2: Modified copper powder, photothermal conversion aid, ligand dispersant and organic carrier are mixed to obtain conductive paste.

[0035] The method for preparing conductive paste provided in this application first coats copper powder with an antioxidant to form a protective layer on the surface of the copper powder, thereby providing dynamic antioxidant protection during sintering and enabling air sintering. Then, the modified copper powder, photothermal conversion aid, ligand dispersant and organic carrier are mixed to make the components highly uniformly distributed, so that the prepared conductive paste can achieve efficient photothermal conversion and heat transfer during photo-sintering, providing a guarantee for rapid densification sintering in a low temperature and air environment.

[0036] The above step S1 has been described in detail in the previous embodiment section regarding the specific selection of antioxidant additives, the amount added, and the particle size of copper powder. To save space, it will not be repeated here.

[0037] In this embodiment, the step of coating the copper powder with an antioxidant includes: dissolving the antioxidant in a mixed solvent of ethanol and isopropanol to obtain a coating solution; adding the copper powder to the coating solution for dispersion treatment, followed by reaction treatment and drying treatment to obtain modified copper powder. During the reaction treatment, the imidazole phosphate containing N and P active atoms, with the N (imidazole ring) having coordination ability, can react with the Cu on the surface of the copper powder. 0 / Cu + A coordination complex layer is formed, thus isolating copper from contact with oxygen and moisture in the environment. P (phosphonate) generates phosphorous acid (H3PO3) or phosphine oxide (P=O) upon heating or mild hydrolysis, further forming a Cu-OP or Cu-P complex layer on the copper powder surface, thus creating a dense organic-inorganic composite protective film. Triethylphosphonate, as a mild reducing agent and coordinating agent, undergoes partial oxidation at 60-80℃ to generate phosphine oxide (P=O), which can reduce trace amounts of Cu2O on the copper powder surface to Cu during the sintering stage. 0 Therefore, the specific ratio of imidazole phosphate and triethylphosphonate works synergistically to achieve dual antioxidant protection of the slurry through "coating and isolation + chemical reduction" throughout the entire process from storage and drying to sintering, enabling the slurry to be sintered in an air environment.

[0038] In the examples, the reaction treatment temperature was 60~80℃ and the time was 1~2h.

[0039] The specific selection and addition amount of the photothermal conversion aid, ligand dispersant and organic carrier in step S2 above have been described in detail in the previous embodiment section, so they will not be repeated here to save space.

[0040] In the embodiments, the step of mixing modified copper powder, photothermal conversion aid, ligand dispersant and organic carrier includes: first dissolving reducing resin, film-forming aid and binder in solvent to form organic carrier; then uniformly dispersing modified copper powder, photothermal conversion aid and ligand dispersant in organic carrier to obtain conductive paste.

[0041] The following description is based on specific embodiments.

[0042] Example 1

[0043] This embodiment provides a conductive paste and its preparation method.

[0044] The conductive paste contains 65 parts of copper powder (D50=150 nm), 2 parts of photothermal conversion aid, 2 parts of ethanolamine, 0.8 parts of antioxidant aid, 0.5 parts of hydroxyethyl cellulose, 0.7 parts of carboxymethyl cellulose, 0.3 parts of polyvinylpyrrolidone, 12 parts of ethylene glycol phenyl ether, and 6 parts of terpineol. The average particle size of the copper powder is 50 nm. The photothermal conversion aid is composed of acetylene black, titanium nitride nanoparticles, and carbon quantum dots in a mass ratio of 5:2:1. The antioxidant aid is composed of imidazole phosphate and triethylphosphonate in a mass ratio of 3:1.

[0045] The method for preparing the conductive paste in this embodiment includes the following steps:

[0046] (1) Preparation of modified copper powder:

[0047] Antioxidant auxiliaries (imidazolium phosphate and triethylphosphonate) were dissolved in a mixed solvent of ethanol and isopropanol to obtain a coating solution; wherein the volume ratio of ethanol to isopropanol was 1:1.

[0048] Copper powder was added to the coating solution and stirred and dispersed for 30 minutes. Then, it was heated to 70°C and stirred for 2 hours. Subsequently, it was dried under reduced pressure at 60°C for 2 hours to obtain modified copper powder.

[0049] (2) Preparation of organic carrier:

[0050] First, polyvinylpyrrolidone, hydroxyethyl cellulose, and carboxymethyl cellulose are dissolved in a mixed solvent of ethylene glycol phenyl ether and terpineol to form an organic carrier.

[0051] (3) Conductive paste:

[0052] Modified copper powder, photothermal conversion aid, and ethanolamine were added to an organic carrier and stirred for 30 minutes at 2000 rpm using a planetary mixer to remove bubbles and obtain a conductive slurry.

[0053] Example 2

[0054] This embodiment provides a conductive paste and its preparation method. The difference from Embodiment 1 is that the photothermal conversion aid is acetylene black.

[0055] Example 3

[0056] This embodiment provides a conductive paste and its preparation method. The difference from Embodiment 1 is that the photothermal conversion aid is titanium nitride nanoparticles.

[0057] Example 4

[0058] This embodiment provides a conductive paste and its preparation method. The difference from Embodiment 1 is that the photothermal conversion aid is carbon quantum dots.

[0059] Example 5

[0060] This embodiment provides a conductive paste and its preparation method. The difference from Embodiment 1 is that the photothermal conversion aid is composed of acetylene black and carbon quantum dots in a mass ratio of 5:1.

[0061] Example 6

[0062] This embodiment provides a conductive paste and its preparation method. The difference from Embodiment 1 is that the antioxidant is imidazole phosphate.

[0063] Example 7

[0064] This embodiment provides a conductive paste and its preparation method. The difference from Embodiment 1 is that the antioxidant is triethylphosphonate.

[0065] Example 8

[0066] This embodiment provides a conductive paste and its preparation method, which differs from Embodiment 1 in that:

[0067] The copper powder is not modified; that is, the preparation method of the conductive paste in this embodiment includes the following steps:

[0068] (1) Preparation of organic carrier:

[0069] First, polyvinylpyrrolidone, hydroxyethyl cellulose, and carboxymethyl cellulose are dissolved in a mixed solvent of ethylene glycol phenyl ether and terpineol to form an organic carrier.

[0070] (2) Conductive paste:

[0071] Copper powder, photothermal conversion aid, antioxidant aid and ethanolamine were added to an organic carrier and stirred for 30 minutes at 2000 rpm using a planetary mixer to remove bubbles and obtain a conductive slurry.

[0072] Comparative Example 1

[0073] This comparative example provides a conductive paste and its preparation method, which differs from Example 1 in that no photothermal conversion aid is added.

[0074] Comparative Example 2

[0075] This comparative example provides a conductive paste and its preparation method, which differs from Example 1 in that no antioxidant is added.

[0076] Relevant performance test analysis:

[0077] The conductive pastes provided in Examples 1-6 and Comparative Examples 1-2 were screen-printed onto a polyimide substrate, respectively. The substrates were then dried at 80°C for 10 minutes, and finally subjected to a 1.5 W / cm strength test in air. -2The conductive paste layer was irradiated with a 450nm blue LED for 30 seconds, raising the substrate temperature to 110℃. After sintering, a film layer with a thickness of approximately 10μm was obtained. The sheet resistance of the film layer was measured using a four-probe tester, and the adhesion of the film layer was tested using a cross-cut adhesion test. The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] As can be seen from Table 1, the film formed by printing the conductive paste provided in Example 1 has better performance than that in Examples 2-8. The main reason is that in Example 1, the combination of acetylene black (macroscopic heat source), titanium nitride nanoparticles (local "hot spots"), and carbon quantum dots ("molecular glue") has a synergistic effect, achieving efficient and uniform photothermal conversion and heat transfer, providing the core driving force for low-temperature dense sintering. Furthermore, the synergistic effect of imidazole phosphate (coating and isolation) and triethylphosphonate (chemical reduction) forms a dense protective film on the surface of copper powder, realizing protection of the paste throughout the entire process from storage, drying to sintering. Therefore, the paste has no oxidation (low sheet resistance), high density, and strong adhesion after sintering at low temperature and in air.

[0081] In Example 2, the lack of local plasmon resonance "hot spots" of titanium nitride nanoparticles and interface optimization effect of carbon quantum dots resulted in reduced photothermal conversion efficiency, insufficient local sintering, decreased conductive network quality, increased sheet resistance, and slightly inferior density and adhesion.

[0082] Example 3 lacks the three-dimensional thermally conductive network of acetylene black and the interfacial effect of carbon quantum dots. Although the local hot spot temperature of titanium nitride nanoparticles is high, the overall heat generation and conduction are uneven, the sintering activity is low, resulting in increased sheet resistance and slightly inferior density and adhesion.

[0083] The carbon quantum dots in Example 4 mainly play the roles of interface optimization and catalysis. However, their photothermal conversion ability is weak, and they cannot serve as the main heat source, resulting in insufficient sintering energy. Consequently, they have high sheet resistance and poor density and adhesion.

[0084] Example 5 shows that the combination of acetylene black and carbon quantum dots provides a basic heat source and interface optimization, but lacks the local high-temperature activation ability of titanium nitride nanoparticles, resulting in insufficient ability to break down the oxide layer and activate surface atoms, leading to a slightly higher sheet resistance than in the example.

[0085] In Example 6, the imidazole phosphate forms a coordination isolation layer that plays a major protective role, but it lacks the dynamic reduction ability of triethylphosphonate during sintering and is insufficient in removing trace oxides, resulting in a higher sheet resistance than in Example 1.

[0086] The triethylphosphonate in Example 7 is mainly reduced, but it lacks the dense pretreatment protective film formed by imidazole phosphate. The copper powder is easily oxidized during storage and early sintering, resulting in a higher sheet resistance than in Example 1.

[0087] In Example 8, the copper powder was not pretreated for anti-oxidation. The subsequent mixing easily caused agglomeration and failed to form a uniform and firm protective layer on the surface of the copper powder. The anti-oxidation effect decreased, resulting in increased sheet resistance, increased porosity, and decreased adhesion.

[0088] The conductive pastes provided in Comparative Examples 1 and 2 resulted in films with significantly inferior performance compared to Example 1. This was primarily because Comparative Example 1 lacked a photothermal conversion aid to convert light energy into heat, preventing the copper powder from achieving dense sintering. Consequently, the conductive network was discontinuous, resulting in high sheet resistance, porous film, and easy peeling. Comparative Example 2 lacked antioxidant protection, causing the copper powder to oxidize rapidly during sintering. The resulting copper oxide insulating layer disrupted the conductive network, leading to increased sheet resistance, more porosity, and decreased adhesion.

[0089] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A conductive paste, characterized in that, It includes the following components in parts by weight: 60-85 parts copper powder, 0.1-5 parts photothermal conversion aid, 0.5-3 parts ligand dispersant, 0.1-2 parts antioxidant aid, and 10.5-28 parts organic carrier; The copper powder has a particle size of 10~300 nm; The photothermal conversion aid comprises acetylene black, titanium nitride nanoparticles, and carbon quantum dots in a mass ratio of (4.5~5.5):(1.5~2.5):(0.5~1.5); The ligand dispersant is selected from one or more of ethanolamine, formamide, and imine compounds; The antioxidant adjuvant comprises imidazole phosphate and triethylphosphonate in a mass ratio of (2~4):(0.5~1.5).

2. The conductive paste as described in claim 1, characterized in that, The copper powder comprises 70-80 parts, the photothermal conversion aid comprises 0.5-2 parts, the ligand dispersant comprises 1-2 parts, the antioxidant aid comprises 0.2-1 parts, and the organic carrier comprises 13-20 parts.

3. The conductive paste as described in claim 1, characterized in that, The organic carrier comprises: 0.2-1 parts of film-forming aid, 0.2-1.5 parts of binder, 0.1-0.5 parts of reducing resin, and 10-25 parts of solvent.

4. The conductive paste as described in claim 3, characterized in that, The film-forming aid comprises 0.3 to 0.6 parts, the binder comprises 0.5 to 1 part, the reducing resin comprises 0.2 to 0.4 parts, and the solvent comprises 12 to 18 parts.

5. The conductive paste as described in claim 3 or 4, characterized in that, At least one of the following conditions must be met: The film-forming aid is selected from one or more of polyurethane, ethylene carbonate, and hydroxyethyl cellulose; The adhesive is selected from one or more of carboxymethyl cellulose, acrylic resin, and polyvinyl butyral; The reducing resin is selected from one or more of polyvinyl alcohol, polyvinylpyrrolidone, and copolymers of styrene and divinylbenzene; The solvent is selected from one or more of ethylene glycol phenyl ether, terpineol, and polyethylene glycol.

6. The conductive paste as described in claim 1, characterized in that, The conductive paste is coated and sintered to form a conductive film with a thickness of 10 μm. The sheet resistance of the conductive film is ≤20 mΩ / □. The conductive film is placed in an air environment with a temperature of 25±5℃ and a relative humidity of 40~60% and left to stand for 48 hours. The resistance change rate of the conductive film is ≤10%.

7. A method for preparing the conductive paste according to any one of claims 1 to 6, characterized in that, Includes the following steps: The copper powder is coated with the antioxidant to obtain modified copper powder; The modified copper powder, the photothermal conversion aid, the ligand dispersant, and the organic carrier are mixed to obtain a conductive slurry.

8. The preparation method according to claim 7, characterized in that, The steps of coating the copper powder with the antioxidant additive include: The antioxidant auxiliary agent was dissolved in a mixed solvent of ethanol and isopropanol to obtain a coating solution; The copper powder is added to the coating solution for dispersion treatment, followed by reaction treatment and drying treatment to obtain modified copper powder.

9. The preparation method according to claim 8, characterized in that, The reaction process is carried out at a temperature of 60-80°C for 1-2 hours.

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