Complex silver ion ink doped silver nanoparticle composite ink and application thereof

Abstract

The invention discloses complex silver ion ink doped silver nanoparticle composite ink and application thereof. The complex silver ion ink doped silver nanoparticle composite ink is prepared by mixing 10-60 mL of complex silver ion ink, 20-40 g of silver nanoparticles, 4-30 mL of a resin solution and 0.8-10 mL of a surfactant. According to the invention, a high-conductivity circuit can be formed on an insulating substrate through various processes such as screen printing, ink-jet printing, pen writing and the like, the line width and the line distance can be flexibly adjusted in a range of 25-5000 microns, the resistivity is stabilized at 5-20 [mu] omega.cm, the binding force between the circuit and the substrate is strong, the circuit is not broken after being bent for multiple times, and the circuit is particularly suitable for the fields of solar cell grid line electrodes and flexible electronics.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of conductive ink, and particularly relates to a complex silver ion ink doped with silver nanoparticle composite ink and application thereof. BACKGROUND

[0002] In recent years, with the rapid development of printing technology and inkjet printing technology, the technology of printing conductive lines on the surface of insulating substrates has become mature and is widely used. This technology has attracted attention due to its efficient and simple preparation process, which usually includes three steps of pattern design, printing and low-temperature curing, so that high-precision conductive lines can be prepared. Compared with the traditional copper-clad plate etching process, this technology has significant advantages: it has a wide range of adaptation and can be compatible with flexible and stretchable substrates such as polyethylene terephthalate (PET) and polyimide (PI) as well as complex three-dimensional structures; the process is environmentally friendly, and on-demand printing can effectively reduce waste generation and resource waste. Therefore, conductive ink printing technology, with its characteristics of high efficiency, environmental protection, adaptation to flexible substrates and high degree of design freedom, gradually replaces traditional manufacturing technology in the fields of flexible electronics, Internet of Things sensors and wearable devices, becomes the mainstream trend of high-value-added electronic manufacturing, and promotes the progress of industry technology.

[0003] Silver, as a noble metal element, has become the core material in conductive ink due to its excellent electrical conductivity and thermal conductivity. Currently, conductive silver ink composed of silver metal particles has been widely used in multiple fields. For example, in the field of solar cells, silver paste is attached to the surface of photovoltaic cell sheets through a screen printing process, and after drying and sintering, a metal electrode is formed for collecting and conducting surface current; in the field of flexible electronics, conductive silver ink is prepared on flexible circuit boards through inkjet printing technology, and the sintered silver coating has good ductility, even in harsh bending tests it can still maintain high electrical conductivity. These applications show that silver-based conductive ink has an irreplaceable position in modern electronic manufacturing.

[0004] However, the existing conductive silver ink and its circuit processing technology still have some deficiencies, mainly reflected in the following aspects: first, the sintering temperature of the ink is relatively high, usually more than 300℃, which requires a higher thermal stability of the flexible substrate, limiting its application on organic substrates; second, the silver coating after sintering is prone to powdering, affecting the stability and reliability of the circuit; third, the resistivity of the silver coating is relatively high, and the conductive performance needs to be improved; fourth, some components of the ink and its sintering products may have adverse effects on the environment or human body, such as the release of volatile organic compounds (VOC). To solve these problems, researchers at home and abroad have proposed some improvement schemes. For example, CN118841204A discloses a low-temperature sintering silver paste for flexible circuit board printing and a preparation method, which improves the powder packing density by mixing nano-silver powder with micro-silver powder, thereby reducing the sheet resistance of the silver layer. However, this method only uses silver powder mixed with a binder, and does not contain complex silver ion ink, resulting in a relatively high sintering temperature, which is not suitable for organic flexible substrates with poor heat resistance. CN117976288A discloses a low-temperature curing type conductive silver paste and a preparation method thereof, which adds silver powder to an organic carrier to prepare a silver paste, and obtains a silver coating with lower resistivity after low-temperature sintering. However, due to the absence of complex silver ion ink, the adhesion between silver particles after sintering is poor, and the silver coating may still be prone to powdering.

[0005] In summary, the existing conductive silver ink technology still has room for improvement in terms of sintering temperature, coating stability, resistivity, and environmental friendliness. To address these issues, it is an urgent need in the current technical field to develop a conductive silver ink with low-temperature sintering, high conductivity, coating stability, and environmental friendliness, as well as a preparation method thereof. SUMMARY

[0006] The present application aims to overcome the deficiencies of the prior art and provide a complex silver ion ink doped with silver nanoparticle composite ink.

[0007] Another object of the present application is to provide a preparation method of the above-mentioned complex silver ion ink doped with silver nanoparticle composite ink.

[0008] Still another object of the present application is to provide the application of the above-mentioned complex silver ion ink doped with silver nanoparticle composite ink.

[0009] The technical solution of the present application is as follows:

[0010] A complex silver ion ink doped silver nanoparticle composite ink is prepared by mixing a complex silver ion ink, silver nanoparticles, a resin solution, and a surfactant in a ratio of 10-60 mL:20-40 g:4-30 mL:0.8-10 mL, wherein

[0011] The complex silver ion ink is prepared by mixing a silver salt, an aqueous complexing solvent, and an auxiliary sintering agent in a ratio of 10-30 g:30-50 mL:1-3 mL,

[0012] The resin solution is prepared by mixing an anionic cellulose ether-based resin or a non-ionic cellulose ether-based resin and pure water in a ratio of 1-10 g:100 mL,

[0013] The surfactant solution is prepared by mixing an anionic surfactant or a non-ionic surfactant and pure water in a ratio of 5-10 g:10-40 mL.

[0014] In a preferred embodiment of the present application, the silver salt is selected from the group consisting of silver acetate, silver formate, and silver carbonate.

[0015] In a preferred embodiment of the present application, the aqueous complexing solvent is at least one selected from the group consisting of aqueous ammonia, an ethylamine solution, and a propylamine solution. The ethylamine solution has a concentration of 30-70 wt%, and the solvent is water, methanol, or ethanol.

[0016] In a preferred embodiment of the present application, the auxiliary sintering agent is selected from the group consisting of acetic acid, glyoxylic acid, and formic acid.

[0017] In a preferred embodiment of the present application, the silver nanoparticles are spherical particles having an average particle size of 2-160 nm.

[0018] In a preferred embodiment of the present application, the anionic cellulose ether-based resin is carboxymethyl cellulose, and the non-ionic cellulose ether-based resin is hydroxypropyl methyl cellulose or hydroxyethyl cellulose.

[0019] In a preferred embodiment of the present application, the anionic surfactant is sodium fatty alcohol polyoxyethylene ether sulfate, and the non-ionic surfactant is a fatty alcohol polyoxyethylene ether or polyethylene glycol.

[0020] The above-mentioned method for preparing a complex silver ion ink doped silver nanoparticle composite ink includes the following steps:

[0021] (1) adding the silver nanoparticles to the complex silver ion ink and stirring to mix uniformly to obtain a homogeneous mixed ink;

[0022] (2) adding the resin solution and the surfactant solution to the homogeneous mixed ink obtained in step (1) and stirring to mix uniformly.

[0023] Use of the above-mentioned complex silver ion ink doped silver nanoparticle composite ink in the preparation of conductive circuit.

[0024] In a preferred embodiment of the present application, the complex silver ion ink doped silver nanoparticle composite ink is applied to the surface of an insulating substrate by screen printing, inkjet printing or pen writing, and then sintered at 120-300°C for 30-240 min in an atmospheric environment to form a conductive circuit; the material of the insulating substrate is selected from polyimide, glass and indium tin oxide (ITO).

[0025] The beneficial effects of the present application are:

[0026] 1. The present application effectively improves the adhesion between silver particles by attaching the complex silver ion ink as the main crosslinking agent to the surface of silver nanoparticles, and precipitating elemental silver to fill the interstitial gaps after sintering, thereby reducing the resistivity of the silver coating to 5-20 μΩ·cm. At the same time, by adding an auxiliary sintering agent to reduce the elemental silver precipitation temperature, the composite ink can be sintered at a low temperature range of 120-300°C, suitable for various substrates such as glass, silicon wafer, ITO layer, PI, PET, PDMS, etc.

[0027] 2. The present application significantly improves the stability of the silver coating by adding resin solution and surfactant solution to the composite ink. The resin enhances the bonding force between silver particles and between silver particles and the substrate, making the silver coating after sintering less likely to fall off or peel off; the surfactant reduces the surface tension of the ink, making the coating process more uniform, and the surface of the silver coating after sintering is smooth without peeling or wrinkling.

[0028] 3. The coating thickness of the composite ink of the present application is controllable, and a 1-30 μm thick silver coating can be formed after single coating and sintering, which can meet the requirements of different processes such as solar cell grid line electrode and flexible electronics for coating thickness.

[0029] 4. The present application selects low-carbon chain, low-boiling point small molecule silver salt, water-based coordination solvent and auxiliary sintering agent, and cooperates with low content of resin and surfactant solution, so that the prepared conductive circuit has high silver content, less impurities, low resistivity and excellent conductivity.

[0030] 5. The composite ink of the present application only volatilizes or decomposes small molecule substances such as carbon dioxide, water, methanol, ammonia and amine during sintering, which is more green and environmentally friendly compared to harmful substances such as formaldehyde that may be produced in traditional technology, and meets the requirements of sustainable development.

[0031] 6、The prepared composite ink can form high-conductivity lines on insulating substrates such as glass, PI, PET, PDMS, silicon wafer and the like through various processes such as screen printing, inkjet printing, pen writing and the like, the line width and line spacing can be flexibly adjusted in the range of 25-5000 μm, the resistivity is stably 4-20 μΩ·cm, the line and the substrate have strong bonding force, the line does not break after multiple bending, and is particularly suitable for solar cell grid line electrodes and flexible electronic fields. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The scanning electron microscope image of the sintered silver coating prepared in Example 1 of the present application.

[0033] Figure 2 The cross-section metallographic microscope image of the sintered silver coating prepared in Example 1 of the present application.

[0034] Figure 3 The atomic force microscope image of the sintered silver coating prepared in Example 1 of the present application.

[0035] Figure 4 The photo of the conductive line printed on the surface of glass by the screen printing process of the complex silver ion ink doped with silver nanoparticles prepared in Example 1 of the present application.

[0036] Figure 5 The scanning electron microscope image of the sintered silver coating prepared in Example 2 of the present application.

[0037] Figure 6 The metallographic microscope image of the sintered silver coating prepared in Example 2 of the present application.

[0038] Figure 7 The scanning electron microscope image of the sintered silver coating prepared in Example 3 of the present application.

[0039] Figure 8 The photo of the silver conductive line drawn on the surface of the polyimide (PI) film directly by the pen writing process of the complex silver ion ink doped with silver nanoparticles prepared in Example 3 of the present application, and the photo of the silver coating after chemical copper plating on the surface after sintering.

[0040] Figure 9 The metallographic microscope image of the sintered silver coating prepared in Comparative Example 1 of the present application.

[0041] Figure 10 The cross-section metallographic microscope image of the sintered silver coating prepared in Comparative Example 2 of the present application.

[0042] Figure 11 The scanning electron microscope image of the sintered silver coating prepared in Comparative Example 3 of the present application. DETAILED DESCRIPTION

[0043] The technical solutions of the present application are further described and explained in the following with reference to the specific embodiments and the accompanying drawings.

[0044] Example 1

[0045] (1) 20 g of silver acetate was dissolved in 18 mL of ammonia water, 12 mL of 70 wt% ethylamine (solvent: water) was added, and the mixture was continuously stirred until the particles were completely dissolved;

[0046] (2) 2 mL of acetic acid was added to the solution prepared in step (1), and after being fully stirred, the insoluble substances and solid precipitates were removed by suction filtration to obtain a clear complex silver ion ink;

[0047] (3) 40 g of silver nanoparticles with an average particle size of 2 nm was added to 60 mL of the complex silver ion ink prepared in step (2), and the mixture was continuously stirred until the solution was uniformly mixed to obtain a homogeneous mixed ink;

[0048] (4) 3 g of carboxymethyl cellulose was added to 100 mL of pure water, and the mixture was continuously stirred until it was dissolved to obtain a resin solution;

[0049] (5) 5 g of fatty alcohol polyoxyethylene ether was added to 20 mL of pure water, and the mixture was continuously stirred until it was dissolved to obtain a surfactant solution;

[0050] (6) 8 mL of the resin solution prepared in step (4) and 0.8 mL of the surfactant solution prepared in step (5) were added to the homogeneous mixed ink prepared in step (3), and the mixture was continuously stirred at room temperature until it was uniformly mixed to obtain a complex silver ion ink doped with silver nanoparticles;

[0051] (7) The complex silver ion ink doped with silver nanoparticles prepared in step (6) was printed on a PI surface using a 400-mesh screen printing screen, and was sintered in an oven at 200°C for 180 min. The resistivity of the sintered silver coating obtained was 7.6 μΩ·cm.

[0052] By Figures 1 to 3 It can be seen that the complex silver ion ink doped with silver nanoparticles prepared in Example 1 has a high degree of sintering, good flatness, and low porosity, and the thickness of the sintered coating can reach 1-30 μm, which meets the requirements of the grid electrode of a solar cell.

[0053] By Figure 4 It can be seen that the complex ink prepared in Example 1 has a clear boundary after printing and sintering, no bleeding, and excellent printing performance.

[0054] Example 2

[0055] (1) 30 g of silver formate was dissolved in 25 mL of ammonia water, 5 mL of propylamine was added, and the mixture was continuously stirred until the particles were completely dissolved;

[0056] (2) Add 3 mL of glyoxylic acid into the solution prepared in step (1), and after fully stirring, remove the insoluble and solid precipitates by suction filtration to obtain a clear silver ion complex ink;

[0057] (3) Add 30 g of silver nanoparticles with an average particle size of 160 nm into 50 mL of the silver ion complex ink prepared in step (2), and continuously stir until the solution is uniformly mixed to obtain a homogeneous mixed ink;

[0058] (4) Add 2 g of hydroxypropyl methylcellulose into 100 mL of pure water, and continuously stir until dissolved to obtain a resin solution;

[0059] (5) Add 10 g of sodium dodecyl sulfate into 40 mL of pure water, and continuously stir until dissolved to obtain a surfactant solution;

[0060] (6) Add 10 mL of the resin solution prepared in step (4) and 10 mL of the surfactant solution prepared in step (5) into the homogeneous mixed ink prepared in step (3), and continuously stir at room temperature until uniformly mixed to obtain a silver ion complex ink doped with silver nanoparticles composite ink;

[0061] (7) Use a 400-mesh silk screen printing screen to print a conductive circuit on a glass surface using the silver ion complex ink doped with silver nanoparticles composite ink prepared in step (6), wherein the line width is 250 μm and the line spacing is 250 μm. Place in an oven and sinter at 120°C for 240 min in a vacuum. The resistivity of the sintered silver coating obtained is 18.7 μΩ·cm.

[0062] Figures 5 to 6 It can be seen that the silver ion complex ink doped with silver nanoparticles composite ink prepared in Example 2 is more uniform after sintering, and the sintering degree is reduced, which can be attributed to the increase in the amount of resin added.

[0063] Example 3

[0064] (1) Add 10 g of silver carbonate into 50 mL of propylamine, and continuously stir until the particles are completely dissolved;

[0065] (2) Add 1 mL of formic acid into the solution prepared in step (1), and after fully stirring, remove the insoluble and solid precipitates by suction filtration to obtain a clear silver ion complex ink;

[0066] (3) Add 30 g of silver nanoparticles with an average particle size of 100 nm into 10 mL of the silver ion complex ink prepared in step (2), and continuously stir until the solution is uniformly mixed to obtain a homogeneous mixed ink;

[0067] (4) Add 10 g of hydroxyethyl cellulose into 100 mL of pure water, and continuously stir until dissolved to obtain a resin solution;

[0068] (5) 10 g of polyethylene glycol was added into 40 mL of pure water, and stirred constantly until dissolved to obtain a surfactant solution;

[0069] (6) 30 mL of the resin solution prepared in step (4) and 4 mL of the surfactant solution prepared in step (5) were added into the homogeneous mixed ink prepared in step (3), and stirred constantly at room temperature until mixed uniformly to obtain a complex silver ion ink doped with silver nanoparticle composite ink;

[0070] (7) After the complex silver ion ink doped with silver nanoparticle composite ink prepared in step (6) was filled into a 500 μm ink filling pen, a pattern was written on the PI surface by the pen, and then placed in a tube furnace for vacuum sintering at 250°C for 120 min. The resistivity of the finally obtained sintered silver coating was 16.2 μΩ·cm.

[0071] Figure 7 It can be seen that the complex silver ion ink doped with silver nanoparticle composite ink prepared in Example 3 has a higher sintering degree, and the silver nanoparticles are more closely bonded, and have a low porosity.

[0072] Figure 8 It can be seen that the composite ink prepared in Example 3 has good coatability and catalytic activity, and can further catalyze the chemical copper plating of a formaldehyde or acetoformic acid system to form a high-conductivity, bend-resistant circuit on a flexible substrate.

[0073] Example 4

[0074] (1) 10 g of silver carbonate was added into 50 mL of 30 wt% ethylamine (solvent: ethanol), and stirred constantly until the particles were completely dissolved;

[0075] (2) 2 mL of formic acid was added into the solution prepared in step (1), and after fully stirred, the insoluble substances and solid precipitates were removed by suction filtration to obtain a clear complex silver ion ink;

[0076] (3) 20 g of silver nanoparticles with an average particle size of 120 nm were added into 40 mL of the complex silver ion ink prepared in step (2), and stirred constantly until the solution was mixed uniformly to obtain a homogeneous mixed ink;

[0077] (4) 10 g of hydroxyethyl cellulose was added into 100 mL of pure water, and stirred constantly until dissolved to obtain a resin solution;

[0078] (5) 10 g of fatty alcohol polyoxyethylene ether sodium sulfate was added into 40 mL of pure water, and stirred constantly until dissolved to obtain a surfactant solution;

[0079] (6) Take 4 mL of the resin solution prepared in step (4) and 1 mL of the surfactant solution prepared in step (5) and add them to the homogeneous mixed ink prepared in step (3), continuously stir at room temperature until mixed evenly, to obtain a complex silver ion ink doped with silver nanoparticle composite ink;

[0080] (7) Using a 600 mesh silk screen printing screen, print the pattern of the complex silver ion ink doped with silver nanoparticle composite ink prepared in step (6) on the ITO surface, place it in a tube furnace and sinter at 280°C for 60 min under vacuum, and the resistivity of the final sintered silver coating is 5.8 μΩ·cm.

[0081] Example 5

[0082] (1) Add 10 g of silver carbonate into 50 mL of 30 wt% ethylamine (solvent is methanol) and continuously stir until the particles are completely dissolved;

[0083] (2) Add 2 mL of formic acid to the solution prepared in step (1), after sufficient stirring, remove the insoluble and solid precipitate by suction filtration, and obtain a clear complex silver ion ink;

[0084] (3) Take 20 g of silver nanoparticles with an average particle size of 8.96 nm and add them to 20 mL of the complex silver ion ink prepared in step (2), continuously stir until the solution is mixed evenly, to obtain a homogeneous mixed ink;

[0085] (4) Add 1 g of hydroxyethyl cellulose into 100 mL of pure water, continuously stir until dissolved, to obtain a resin solution;

[0086] (5) Add 10 g of fatty alcohol polyoxyethylene ether sodium sulfate into 40 mL of pure water, continuously stir until dissolved, to obtain a surfactant solution;

[0087] (6) Take 4 mL of the resin solution prepared in step (4) and 1 mL of the surfactant solution prepared in step (5) and add them to the homogeneous mixed ink prepared in step (3), continuously stir at room temperature until mixed evenly, to obtain a complex silver ion ink doped with silver nanoparticle composite ink;

[0088] (7) Using a 500 mesh silk screen printing screen, print the pattern of the complex silver ion ink doped with silver nanoparticle composite ink prepared in step (6) on the ITO surface, place it in a tube furnace and sinter at 300°C for 60 min under vacuum, and the resistivity of the final sintered silver coating is 4.3 μΩ·cm.

[0089] Comparative Example 1

[0090] The comparative composite ink prepared in Comparative Example 1 is similar to the complex silver ion ink doped with silver nanoparticle composite ink of Example 1, except that no resin solution is added.

[0091] Figure 9 It can be seen that the surface of the sintered silver coating prepared by sintering the comparative composite ink prepared in Comparative Example 1 is uneven and not dense, and has many holes.

[0092] Comparative Example 2

[0093] The preparation of the comparative composite ink prepared in Comparative Example 2 is similar to that of the complex silver ion ink doped with silver nanoparticle composite ink of Example 2, except that no surfactant solution is added.

[0094] Figure 10 It can be seen that the sintered silver coating prepared by sintering the comparative composite ink prepared in Comparative Example 2 has uneven thickness and large surface roughness.

[0095] Comparative Example 3

[0096] The comparative composite ink prepared in Comparative Example 3 is similar to the complex silver ion ink doped with silver nanoparticle composite ink of Example 3, except that the average particle size of the silver nanoparticles used is 500 nm.

[0097] Figure 11 It can be seen that the silver particles in the sintered silver coating prepared by sintering the comparative composite ink prepared in Comparative Example 3 are relatively dispersed and have poor adhesion. The properties of the sintered silver coatings obtained by sintering the complex silver ion ink doped with silver nanoparticle composite ink prepared in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1.

[0098] Table 1

[0099] Resistivity (pOhm-cm) Surface roughness (nm) Example 1 7.6 391 Example 2 18.7 209 Example 3 16.2 429 Example 4 5.8 264 Example 5 4.3 233 Comparative Example 1 - 1638 Comparative Example 2 - 2741 Comparative Example 3 147.1 936

[0100] From the above Examples 1 to 5 and Comparative Example 1, it can be found that without adding the resin solution, the silver particles in the silver coating after sintering of the composite ink have large gaps, are easy to form holes, and have large surface roughness and resistivity after sintering. After adding the resin solution with a mass fraction of 10%, the silver nanoparticles in the composite ink are uniformly distributed, the sintered silver coating is uniform and dense, the bonding force between the silver particles in the coating is good, the porosity of the coating is low, and the resistivity is low. With the increase of the amount of the resin solution (10%-30%), the resistivity increases, but the surface becomes more flat.

[0101] From the above Examples 1 to 5 and Comparative Example 2, it can be found that without adding the surfactant solution, the composite ink has poor coatability, the thickness of the silver coating after sintering is uneven, the surface roughness is large, and the resistivity cannot be accurately measured. After adding the surfactant solution with a mass fraction of 4%, the coatability of the composite ink is enhanced, the pattern after coating does not shrink after heating, the surface of the sintered silver coating is flat, and the thickness is uniform. With the increase of the amount of the surfactant solution (1%-10%), the surface roughness decreases.

[0102] It can be found from the above Examples 1 to 5 and Comparative Example 3 that when silver nanoparticles having a particle size distribution of 500 nm are used, the degree of adhesion between silver particles in the silver coating after sintering is low, the amount of silver element on the surface of the silver nanoparticles covered with complex silver ion ink after reduction is small, the degree of adhesion between silver nanoparticles is low, and the resistivity is high. When nanoparticles having a relatively small particle size distribution (2 to 160 nm) are used, the degree of adhesion between silver particles is high, the degree of sintering of the silver coating increases, and the resistivity decreases.

[0103] The above description is merely preferred embodiments of the present application, and thus is not intended to limit the scope of the present application. It is to be understood that the equivalent changes and modifications to the present application are to be construed as falling within the scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A complex silver ion ink doped with silver nanoparticles composite ink, characterized by: The invention is prepared by mixing complex silver ion ink, silver nanoparticles, resin solution and surfactant solution in a ratio of 10-60mL:20-40g:4-30mL:0.8-10mL, wherein: The complex silver ion ink is prepared by mixing silver salt, aqueous coordination solvent and auxiliary sintering agent in a ratio of 10-30g:30-50mL:1-3mL. The resin solution is prepared by mixing anionic cellulose ether resin or nonionic cellulose ether resin and pure water in a ratio of 1-10g:100mL. The surfactant solution is prepared by mixing anionic surfactant or nonionic surfactant and pure water in a ratio of 5-10g:10-40mL.

2. The silver nanoparticle-doped complex silver ion ink according to claim 1, wherein: The silver salt is selected from silver acetate, silver formate and silver carbonate.

3. The silver nanoparticle-doped complex silver ion ink according to claim 1, wherein: The aqueous coordination solvent is at least one of ammonia water, ethylamine solution and propylamine.

4. The silver nanoparticle-doped complex silver ion ink according to claim 1, wherein: The auxiliary sintering agent is selected from acetic acid, glyoxylic acid and formic acid.

5. The complex silver ion ink doped with silver nanoparticles composite ink according to claim 1, characterized in that: The silver nanoparticles are spherical particles with an average particle diameter of 2-160 nm.

6. The silver nanoparticle-doped complex silver ion ink according to claim 1, wherein: The anionic cellulose ether resin is carboxymethyl cellulose, and the nonionic cellulose ether resin is hydroxypropyl methyl cellulose or hydroxyethyl cellulose.

7. The complex silver ion ink doped with silver nanoparticles composite ink according to claim 1, characterized in that: The anionic surfactant is sodium lauryl sulfate or sodium fatty alcohol polyoxyethylene ether sulfate, and the nonionic surfactant is fatty alcohol polyoxyethylene ether or polyethylene glycol.

8. The method for preparing the complex silver ion ink doped with silver nanoparticles according to any one of claims 1 to 7, characterized in that: The steps include: (1) adding the silver nanoparticles to the complex silver ion ink, stirring and mixing uniformly to obtain a homogeneous mixed ink; (2) adding the resin solution and the surfactant solution to the homogeneous mixed ink obtained in step (1), stirring and mixing them uniformly to obtain the ink.

9. Use of the complex silver ion ink doped with silver nanoparticles composite ink according to any one of claims 1 to 7 in the preparation of conductive circuits.

10. The use according to claim 9, characterized in that: The complex silver ion ink doped with silver nanoparticle composite ink is coated on the surface of an insulating substrate by screen printing, inkjet printing or pen writing, and then sintered at 120-300° C. for 30-240 minutes in an atmospheric environment or a vacuum environment to form a conductive circuit; the insulating substrate is made of a material selected from polyimide, glass and indium tin oxide.

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