Metal-doped graphene oxide conductive ink as well as preparation method and application thereof

Abstract

The invention belongs to the field of photoelectric materials and devices, and discloses a method for preparing metal-doped graphene oxide conductive ink, which comprises the following steps: immersing a metal base material into a graphene oxide aqueous solution, and carrying out redox reaction to prepare reduced graphene oxide ink loaded with metal oxide particles. According to the method disclosed by the invention, the preparation of the reduced graphene oxide conductive ink loaded with the metal oxide particles is realized through in-situ spontaneous oxidation-reduction reaction of the graphene oxide and the metal base material. Compared with the traditional metal-doped graphene ink preparation method, the method has the advantages that in-situ low-temperature oxidation reduction can be realized, the use of an organic solvent or ionic liquid and the like is avoided, the residue of organic matters is reduced, and meanwhile, the electrical conductivity is obviously improved by in-situ embedding of metal oxide particles.

Description

Technical Field

[0001] The present invention belongs to the technical field related to conductive ink, and more specifically, relates to a metal-doped graphene oxide conductive ink and a preparation method and application thereof. Background Art

[0002] Conductive ink plays a vital role in the manufacture of various traditional and flexible electronic devices. High-performance conductive ink should have excellent conductivity, strong substrate adhesion, and be easy to store for a long time.

[0003] Conductive inks are mainly divided into metal-based conductive inks and carbon-based conductive inks. Currently, the most commonly used conductive ink on the market is the conductive ink made of silver nanomaterials, but its raw materials are too expensive. Although the raw materials of copper-based conductive inks are relatively cheap, their easy oxidation nature also limits their application to a certain extent.

[0004] The resistivity of carbon-based inks currently on the market is generally high. The use of graphene to prepare high-performance printing inks is expected to obtain conductivity comparable to that of silver conductive inks, better ease of use and stability, while reducing ink costs, thereby promoting the development of flexible printed electronics technology. At present, graphene conductive inks use more highly polar solvents such as NMP, cyclohexanone, pinene alcohol, and water. The properties of graphene prepared by different solvents and different methods are different, and the different coated stabilizers also affect the performance of conductive inks to a certain extent. Graphene conductive inks, the properties of graphene prepared by different methods are also different, which will also affect the performance of the prepared conductive inks to a certain extent. Invention patent CN117423491A discloses a graphene conductive ink prepared from cyclohexanone, ethyl cellulose and flake graphite. Invention patent CN116694139A discloses a method of dispersing graphite in a surfactant to form a graphene ink. Both conductive inks use surfactants, compound addition and other processes, and the preparation process is complicated. Therefore, it is urgent to develop corresponding technical means to prepare graphene conductive inks in a green, simple and efficient manner. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a method for preparing a metal-doped graphene oxide conductive ink. The conductive ink of the present invention adopts an in-situ self-reduction technology, and the rich oxygen-containing groups provided by graphene oxide provide good adsorption sites for metal ions, thereby promoting the growth of metal nanoparticles, realizing the reduction of graphene oxide and the deposition and growth of metal oxide nanoparticles in situ, and completing the preparation of the conductive ink conveniently and quickly, thereby solving the technical problem of the prior art that the conductive ink preparation is dependent on high temperature conditions or other toxic and reducing agents.

[0006] In order to achieve the above-mentioned purpose, in a first aspect of the present invention, a method for preparing a metal-doped graphene oxide conductive ink is provided, wherein a metal substrate is immersed in an aqueous solution of graphene oxide to cause an oxidation-reduction reaction, thereby obtaining a reduced graphene oxide ink loaded with metal oxide particles.

[0007] Preferably, the oxidation-reduction reaction temperature is 10° C. to 80° C.; the oxidation-reduction reaction time is 10 min to 24 h.

[0008] Preferably, the metal substrate is a metal mesh, a metal foil, a metal sheet, a metal strip, a metal ball, a metal block, a metal tube, or a metal wire; the material of the metal substrate is nickel, iron, copper, cobalt, zinc or tin, or an alloy containing at least two metals of nickel, iron, copper, cobalt, zinc and tin.

[0009] Preferably, the concentration of graphene oxide in the graphene oxide aqueous solution is 0.1 mg / mL to 80 mg / mL.

[0010] Preferably, the graphene oxide is single-layer graphene oxide, few-layer graphene oxide or multi-layer graphene oxide.

[0011] Preferably, the graphene oxide aqueous solution also contains a conductive agent.

[0012] Preferably, the conductive agent is at least one of carbon nanotubes, superconductive carbon black, rhodanine and polyvinyl pyrrolidone.

[0013] Preferably, the mass ratio of the graphene oxide to the conductive agent is (5-20):1.

[0014] In order to achieve the above-mentioned object, in another aspect of the present invention, a reduced graphene oxide ink loaded with metal oxide particles prepared by the preparation method according to the first aspect of the present invention is provided.

[0015] In order to achieve the above object, in another aspect of the present invention, a reduced graphene oxide ink loaded with metal oxide particles as in another aspect of the present invention is provided for use as a conductive ink for inkjet printing.

[0016] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0017] (1) The present invention realizes the preparation of reduced graphene oxide conductive ink loaded with metal oxide particles through the in-situ spontaneous redox reaction of graphene oxide and metal substrate. This method only requires graphene oxide as an oxidant and a metal substrate as a reducing agent. The rich oxygen-containing groups provided by graphene oxide provide good adsorption sites for metal ions, thereby promoting the growth of metal nanoparticles, realizing the reduction of graphene oxide and the deposition and growth of metal oxide nanoparticles in situ, and completing the preparation of conductive ink conveniently and quickly. Compared with the preparation of traditional metal-doped graphene ink, it can be oxidized and reduced in situ at low temperature, and avoids the use of organic solvents or ionic liquids, etc., reducing the residue of organic matter. At the same time, the in-situ embedding of metal oxide particles significantly improves the conductivity.

[0018] (2) In the preparation process of the conductive ink of the present invention, metal materials at the macroscopic level are selected, including metal mesh, metal particles, metal foil, metal sheet, metal strip, metal ball, metal block, metal tube, or metal wire, etc., as the inducer of graphene oxide conductive ink, and the reduction of graphene oxide is promoted by thermodynamic induction of spontaneous redox reaction, and metal doping is performed at the same time to complete the preparation of conductive ink. Compared with one-dimensional materials such as metal nanowires, which are usually viscous dispersions, due to quantum effects, electrons will occupy discrete energy bands rather than continuous states, which makes them highly conductive, while the metal substrate of the present application relies on the conductive properties of the material itself, and the preparation process is more convenient and stable. At the same time, after the preparation of the conductive ink is completed once, the metal substrate of the present invention can be recycled after the metal substrate is cleaned, realizing green circulation and efficient participation in the preparation reaction.

[0019] (3) In the preparation process of the conductive ink of the present invention, carbon nanotubes, rhodanine, etc. can be added as conductive agents to the graphene oxide aqueous solution to further enhance the conductivity of the system.

[0020] (4) The preparation process of the conductive ink of the present invention does not require the addition of other reagents, thus getting rid of the reliance on high temperature conditions or toxic reducing reagents in the prior art. At the same time, by precisely controlling the shape or material of the substrate and regulating the reaction time and temperature, different conductivities and viscosities can be obtained.

[0021] (5) The composite conductive ink prepared based on nickel metal mesh in the preferred embodiment 1 of the present invention has a viscosity of 7.32 mPa·s and a square resistance of 680 Ω / sq under mild reaction conditions, and can be effectively used in various printing and spraying equipment (the viscosity of the conductive ink for inkjet printing is between 5-10 mPa·s).

[0022] In summary, the manufacturing method is simple in process and convenient in operation, and this method can get rid of the dependence on high temperature conditions or other toxic reducing agents. The conductive ink is printed or printed on the substrate by inkjet printing and processed, and finally assumes various functions such as conductor, conductive circuit, resistor, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the reaction model of the metal substrate and the graphene oxide aqueous solution in Example 1 used in the present invention.

[0024] Figure 2 This is a physical picture of the reduced graphene oxide ink loaded with metal oxide particles used in Example 1 of the present invention.

[0025] Figure 3 This is a SEM image of the reduced graphene oxide ink loaded with metal oxide particles used in Example 1 of the present invention.

[0026] Figure 4 This is a TEM image of the reduced graphene oxide ink loaded with metal oxide particles taken in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] The reduced graphene oxide ink loaded with metal oxide particles prepared by the present invention utilizes the redox reaction between graphene oxide and a metal substrate. The abundant oxygen-containing groups provided by the graphene oxide provide good adsorption sites for metal ions, thereby promoting the growth of metal nanoparticles and completing the spontaneous in-situ deposition of metal oxide particles on graphene sheets.

[0029] Figure 1 The reaction model in the embodiment used in the present invention is: Figure 1 It can be seen that graphene oxide (GO) itself is an efficient oxidant with rich oxidized functional groups on its surface. Any form of single metal substrate (Ni, Cu, Fe, Co, Zn or Sn, etc.) or metal alloy (NiCu, CuFe, CoFe, CoZn, NiCoCu, CuFeCo or CuNiFe, etc.) is reducing. Therefore, the redox reaction between GO and the metal substrate is used to reduce graphene oxide and embed metal oxide particles to form a conductive ink.

[0030] Several preparation methods of the present invention are exemplified below, specifically as follows:

[0031] As an optional embodiment, a method for preparing reduced graphene oxide ink loaded with metal oxide particles is provided, comprising the following steps:

[0032] (a) Take a metal substrate of a certain shape, clean the surface with acetone, and vacuum dry it for later use.

[0033] (b) Immersing a clean and dry metal substrate in an aqueous solution of graphene oxide at a mass concentration of 0.1 mg / mL to 80 mg / mL, and precisely controlling the reaction conditions (reaction temperature between 10°C and 80°C, reaction time between 10 min and 24 h) to allow an in-situ redox reaction between the graphene oxide and the metal substrate to produce a conductive ink.

[0034] (c) The metal plate obtained in (b) is taken out from the system, and the surface is cleaned with a small amount of deionized water for subsequent use.

[0035] As an optional embodiment, a method for preparing reduced graphene oxide ink loaded with metal oxide particles is provided, comprising the following steps:

[0036] (a) adding multi-walled carbon nanotubes to a graphene oxide aqueous solution having a mass concentration of 0.1 mg / mL to 80 mg / mL, and obtaining a mixed solution by ultrasonic dispersion, wherein the mass ratio of the multi-walled carbon nanotubes to the graphene oxide is 1:(10-20).

[0037] (b) Immersing a clean metal substrate in the mixed turbid solution obtained in (a), and precisely controlling the reaction conditions (reaction temperature is between 10°C and 80°C, and reaction time is between 10 min and 24 h) to allow the carbon nanotubes / graphene oxide to undergo a redox reaction with the metal substrate to produce a conductive ink.

[0038] (c) The metal substrate obtained in (b) is taken out from the system, and the surface is cleaned with a small amount of deionized water for subsequent use.

[0039] As an optional embodiment, a method for preparing reduced graphene oxide ink loaded with metal oxide particles is provided, comprising the following steps:

[0040] (a) adding superconductive carbon black (Super P) to a graphene oxide aqueous solution having a mass concentration of 0.1 mg / mL to 80 mg / mL, and obtaining a mixed solution by ultrasonic dispersion, wherein the mass ratio of the superconductive carbon black to the graphene oxide is 1:(10-20).

[0041] (b) Immersing a clean metal plate in the mixed turbid liquid obtained in (a), precisely controlling the reaction conditions (reaction temperature between 10°C and 80°C, reaction time between 10 min and 24 h) to allow the superconducting carbon black / graphene oxide to undergo a redox reaction with the metal substrate to produce a conductive ink.

[0042] (c) The metal substrate obtained in (b) is taken out from the system, and the surface is cleaned with a small amount of deionized water for subsequent use.

[0043] As an optional embodiment, a method for preparing reduced graphene oxide ink loaded with metal oxide particles is provided, comprising the following steps:

[0044] (a) Rhodanine and PVP are added to a graphene oxide aqueous solution having a mass concentration of 0.1 mg / mL to 80 mg / mL, and ultrasonic dispersion is used to obtain a mixed solution, wherein the mass ratio of rhodanine / polyvinyl pyrrolidone to graphene oxide is 1:1:(10-20).

[0045] (b) Immersing a clean metal substrate in the mixed turbid solution obtained in (a), and precisely controlling the reaction conditions (temperature between 10°C and 80°C, reaction time between 10 min and 24 h) to allow rhodanine / polyvinyl pyrrolidone / graphene oxide to undergo a redox reaction with the metal substrate to produce a conductive ink.

[0046] (c) The metal substrate obtained in (b) is taken out from the system, and the surface is cleaned with a small amount of deionized water for subsequent use.

[0047] The present invention can realize large-scale, green and efficient preparation of graphene-based high-performance ink by adjusting the type of metal substrate, the type and composition of the conductive agent, graphene and the concentration of the conductive agent, etc. The metal substrate and graphene react in situ to obtain metal-doped graphene composite ink, and the function of the prepared ink is improved through the action of different conductive agents, thereby optimizing its practicability.

[0048] In some embodiments, the metal substrate is mainly in the shape of metal particles, metal mesh, metal foil, metal sheet, metal strip, metal ball, metal block, metal tube, metal wire, etc.; the main material is nickel, iron, copper, cobalt, zinc or tin, or the metal substrate is an alloy of at least two metals among copper, iron, cobalt, nickel, zinc and tin.

[0049] In some embodiments, the graphene oxide is a single-layer graphene oxide, a few-layer graphene oxide, or a multi-layer graphene oxide.

[0050] In some embodiments, the conductive agent is mainly carbon nanotubes, superconductive carbon black, rhodanine, polyvinyl pyrrolidone (PVP), etc., or a combination of several thereof.

[0051] The above method is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only used to explain the present invention, and the scope of protection of the present invention is not limited thereto.

[0052] It should be noted that the graphene oxide selected in Examples 1-16 given in the present invention is specifically multilayer graphene oxide.

[0053] Embodiment 1:

[0054] A 10 cm×10 cm nickel metal mesh was immersed in 6 mol / L hydrochloric acid, and the surface oxide layer was removed and then washed with acetone, and finally washed with deionized water.

[0055] The metal mesh was placed in a 0.1 mg / mL graphene oxide aqueous solution, and the graphene oxide (GO) and the metal mesh underwent an in-situ redox reaction by precisely controlling the reaction temperature and time.

[0056] After the required reaction time, the nickel metal mesh is taken out from the system, the surface of the nickel metal mesh is cleaned with deionized water, and dried for reuse.

[0057] The obtained black color is reduced graphene oxide conductive ink loaded with nickel oxide.

[0058] The conductive ink prepared according to Example 1 is a black viscous liquid. After testing, the viscosity is 7.32 mPa·s and the square resistance is 680Ω / sq.

[0059] Figure 2 This is a physical picture of the reduced graphene oxide conductive ink product loaded with nickel oxide in Example 1 of the present invention. Viscosity and square resistance tests show that the conductive ink has relatively large viscosity and good conductivity.

[0060] Figure 3 This is the SEM of the reduced graphene oxide conductive ink loaded with nickel oxide in Example 1 of the present invention, Figure 4 This is a TEM image of the reduced graphene oxide conductive ink loaded with nickel oxide in Example 1 of the present invention. SEM shows that the reduced graphene oxide maintains a complete graphene sheet, and the TEM image proves that the ultrafine metal oxide nanoparticles are evenly distributed on the graphene sheet.

[0061] The method for preparing the metal-doped graphene oxide conductive ink of the present invention is to mix the above components and form a graphene-based high-performance ink with controllable composition by controlling the reaction time, temperature, concentration, etc. The operation steps of the following Examples 2-16 are as shown in the above examples, and the viscosity and square resistance of the corresponding conductive ink are tested. Specifically, the raw materials, reaction conditions and performance data involved in Examples 1-16 are shown in Table 1 below.

[0062] Table 1: Raw materials, reaction conditions and performance data of Examples 1-16

[0063]

[0064]

[0065] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the present invention and its equivalent technology, the present invention is also intended to include these changes and variations. The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and their protection scope is not limited thereto. Equivalent substitutions or changes made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention.

Claims

1. A method for preparing metal-doped graphene oxide conductive ink, characterized in that: The method comprises immersing a metal substrate in an aqueous solution of graphene oxide to cause an oxidation-reduction reaction, thereby obtaining reduced graphene oxide ink loaded with metal oxide particles.

2. The method for preparing metal-doped graphene oxide conductive ink according to claim 1, characterized in that: The reaction temperature of the oxidation-reduction is 10°C to 80°C; the reaction time of the oxidation-reduction is 10min to 24h.

3. The method for preparing metal-doped graphene oxide conductive ink according to claim 1, characterized in that: The metal substrate is a metal mesh, metal foil, metal sheet, metal strip, metal ball, metal block, metal tube or metal wire; the material of the metal substrate is nickel, iron, copper, cobalt, zinc or tin, or an alloy containing at least two metals of nickel, iron, copper, cobalt, zinc and tin.

4. The method for preparing metal-doped graphene oxide conductive ink according to claim 1, characterized in that: The concentration of graphene oxide in the graphene oxide aqueous solution is 0.1 mg / mL to 80 mg / mL.

5. The method for preparing metal-doped graphene oxide conductive ink according to claim 1, characterized in that: The graphene oxide is single-layer graphene oxide, few-layer graphene oxide or multi-layer graphene oxide.

6. The method for preparing metal-doped graphene oxide conductive ink according to claim 1, characterized in that: The graphene oxide aqueous solution also contains a conductive agent.

7. The method for preparing metal-doped graphene oxide conductive ink according to claim 6, characterized in that: The conductive agent is at least one of carbon nanotubes, superconductive carbon black, rhodanine and polyvinyl pyrrolidone.

8. The method for preparing metal-doped graphene oxide conductive ink according to claim 6, characterized in that: The mass ratio of the graphene oxide to the conductive agent is (5-20):

1.

9. Reduced graphene oxide ink loaded with metal oxide particles obtained by the preparation method according to any one of claims 1 to 8. 10 . The reduced graphene oxide ink loaded with metal oxide particles according to claim 9 is used as a conductive ink for inkjet printing.

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