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

Abstract

The application 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 substrate into an aqueous solution of graphene oxide, and carrying out a redox reaction to obtain reduced graphene oxide ink loaded with metal oxide particles. The method realizes the preparation of reduced graphene oxide conductive ink loaded with metal oxide particles through in-situ spontaneous redox reaction of graphene oxide and the metal substrate. Compared with the traditional method for preparing metal-doped graphene ink, the method can realize in-situ low-temperature redox, avoids the use of organic solvents or ionic liquids, reduces the residual organic matter, and significantly improves the conductivity by in-situ embedding of metal oxide particles.

Description

Technical Field

[0001] This invention belongs to the technical field of conductive inks, and more specifically, relates to a metal-doped graphene oxide conductive ink, its preparation method, and its application. Background Technology

[0002] Conductive inks play a crucial role in the manufacture of various traditional and flexible electronic devices. High-performance conductive inks should possess excellent conductivity, strong substrate adhesion, and the ability to be stored for extended periods.

[0003] Conductive inks are mainly divided into metal-based conductive inks and carbon-based conductive inks. Currently, the most widely used conductive inks on the market are made of silver nanomaterials, but their raw materials are too expensive. While copper-based conductive inks have relatively cheaper raw materials, their susceptibility to oxidation limits their application to some extent.

[0004] Currently, commercially available carbon-based inks generally have high resistivity. Utilizing graphene to prepare high-performance printing inks holds promise for achieving conductivity comparable to silver conductive inks, better usability, and stability, while simultaneously reducing ink costs, thereby promoting the development of flexible printed electronics technology. Currently, graphene conductive inks often use highly polar solvents such as NMP, cyclohexanone, terpineol, and water. Different solvents and methods result in different graphene properties, and the different stabilizers used also affect the performance of the conductive ink to some extent. The properties of graphene prepared using different methods also vary, which will further influence the performance of the resulting conductive ink. 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 of these conductive inks employ surfactants and compound addition processes, resulting in complex preparation procedures. Therefore, there is an urgent need to develop corresponding technologies to prepare graphene conductive inks in a green, simple, and efficient manner. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for preparing metal-doped graphene oxide conductive ink. The conductive ink of this invention employs in-situ self-reduction technology. The abundant oxygen-containing groups provided by graphene oxide offer excellent adsorption sites for metal ions, thereby promoting the growth of metal nanoparticles. This in-situ reduction of graphene oxide and the deposition and growth of metal oxide nanoparticles facilitate rapid preparation of the conductive ink, thus solving the technical problem of dependence on high-temperature conditions or other toxic or reducing agents in the preparation of conductive inks in existing technologies.

[0006] To achieve the above objectives, in a first aspect of the present invention, a method for preparing metal-doped graphene oxide conductive ink is provided, wherein a metal substrate is immersed in an aqueous solution of graphene oxide to undergo a redox reaction, thereby obtaining a reduced graphene oxide ink loaded with metal oxide particles.

[0007] Preferably, the redox reaction temperature is 10℃~80℃; the redox reaction time is 10min~24h.

[0008] Preferably, 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 of the metals nickel, iron, copper, cobalt, zinc, and tin.

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

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

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

[0012] Preferably, the conductive agent is at least one of carbon nanotubes, superconducting carbon black, rhodanine, and polyvinylpyrrolidone.

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

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

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

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0017] (1) This invention achieves the preparation of reduced graphene oxide conductive ink loaded with metal oxide particles through an in-situ spontaneous redox reaction between graphene oxide and a metal substrate. This method only requires graphene oxide as the oxidant and the metal substrate as the reducing agent. The abundant oxygen-containing groups provided by graphene oxide offer excellent adsorption sites for metal ions, thereby promoting the growth of metal nanoparticles. In-situ reduction of graphene oxide and deposition and growth of metal oxide nanoparticles are achieved, facilitating rapid preparation of conductive ink. Compared to traditional metal-doped graphene ink preparation, this method enables in-situ low-temperature redox and avoids the use of organic solvents or ionic liquids, reducing organic residues. Simultaneously, the in-situ embedding of metal oxide particles significantly improves conductivity.

[0018] (2) In the preparation process of the conductive ink of this invention, macroscopic metal materials are selected, including metal mesh, metal particles, metal foil, metal sheet, metal strip, metal ball, metal block, metal tube, or metal wire, etc., as inducing agents for graphene oxide conductive ink. Through thermodynamically induced spontaneous redox reaction, the reduction of graphene oxide is promoted, and metal doping is carried out simultaneously 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 occupy discrete energy bands rather than continuous states, making them highly conductive. The metal substrate of this application relies on the conductive properties of the material itself, making the preparation process more convenient and stable. At the same time, after the preparation of conductive ink once, the metal substrate of this invention can be recycled after cleaning, realizing green recycling and efficient participation in the preparation reaction.

[0019] (3) In the preparation process of the conductive ink of the present invention, carbon nanotubes, rhodanine and other conductive agents can be added to the aqueous solution of graphene oxide 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 eliminating the dependence on high temperature conditions or toxic reducing agents in the prior art. At the same time, by precisely controlling the morphology or material of the substrate and regulating the reaction time and temperature, different conductivity and viscosity can be obtained.

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

[0022] In summary, this manufacturing method is simple and easy to operate, eliminating the reliance on high-temperature conditions or other toxic reducing agents. Conductive ink is printed onto a substrate via inkjet printing or inkjet printing and then processed to ultimately perform various functions such as conductor, conductive circuit, and resistance. Attached Figure Description

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

[0024] Figure 2 This is a physical image of the reduced graphene oxide ink loaded with metal oxide particles as described in Example 1 of this 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 this invention.

[0026] Figure 4 This is a TEM image of the reduced graphene oxide ink loaded with metal oxide particles as described in Example 1 of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0028] The present invention provides a reduced graphene oxide ink loaded with metal oxide particles. This ink utilizes the redox reaction between graphene oxide and a metal substrate. The abundant oxygen-containing groups provided by 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 used in the embodiments of this invention is derived from... Figure 1 It is known that graphene oxide (GO) itself is a highly efficient oxidant with abundant oxidative functional groups on its surface. Any form of elemental metal substrate (Ni, Cu, Fe, Co, Zn or Sn, etc.) or metal alloy (NiCu, CuFe, CoFe, CoZn, NiCoCu, CuFeCo or CuNiFe, etc.) has reducing properties. Therefore, by utilizing the redox reaction between GO and metal substrate, graphene oxide can be reduced while metal oxide particles are embedded to form conductive ink.

[0030] The following are examples of several preparation methods of the present invention, as detailed below:

[0031] As an optional implementation, 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) Immerse a clean and dry metal substrate in an aqueous solution of graphene oxide with a mass concentration of 0.1 mg / mL to 80 mg / mL, and precisely control the reaction conditions (reaction temperature between 10℃ and 80℃, reaction time between 10 min and 24 h) to allow graphene oxide to undergo an in-situ redox reaction with the metal substrate to obtain conductive ink.

[0034] (c) Remove the metal plate obtained in (b) from the system, clean the surface with a small amount of deionized water, and prepare it for subsequent use.

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

[0036] (a) Multi-walled carbon nanotubes were added to an aqueous solution of graphene oxide with a mass concentration of 0.1 mg / mL to 80 mg / mL, and the mixture was dispersed by ultrasonication to obtain a mixture, wherein the mass ratio of multi-walled carbon nanotubes to graphene oxide was 1:(10 to 20).

[0037] (b) Immerse a clean metal substrate in the mixed turbid liquid obtained in (a), and precisely control the reaction conditions (reaction temperature between 10℃ and 80℃, reaction time between 10 min and 24 h) to allow carbon nanotubes / graphene oxide to undergo an oxidation-reduction reaction with the metal substrate to obtain conductive ink.

[0038] (c) Remove the metal substrate obtained in (b) from the system, clean the surface with a small amount of deionized water, and prepare for subsequent use.

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

[0040] (a) Add superconducting carbon black (Super P) to an aqueous solution of graphene oxide with a mass concentration of 0.1 mg / mL to 80 mg / mL, and disperse the mixture by ultrasonication to obtain a mixture, wherein the mass ratio of superconducting carbon black to graphene oxide is 1:(10 to 20).

[0041] (b) Immerse a clean metal plate in the mixed turbid liquid obtained in (a), and precisely control the reaction conditions (reaction temperature between 10℃ and 80℃, reaction time between 10 min and 24 h) to allow the superconducting carbon black / graphene oxide to undergo an oxidation-reduction reaction with the metal substrate to obtain conductive ink.

[0042] (c) Remove the metal substrate obtained in (b) from the system, clean the surface with a small amount of deionized water, and prepare for subsequent use.

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

[0044] (a) Rhodanine and PVP were added to an aqueous solution of graphene oxide with a mass concentration of 0.1 mg / mL to 80 mg / mL, and the mixture was dispersed by ultrasonication to obtain a mixture, wherein the mass ratio of rhodanine / polyvinylpyrrolidone to graphene oxide was 1:1:(10 to 20).

[0045] (b) Immerse a clean metal substrate in the mixed turbid liquid obtained in (a), and precisely control the reaction conditions (temperature between 10℃ and 80℃, reaction time between 10 min and 24 h) to allow rhodanine / polyvinylpyrrolidone / graphene oxide to undergo an oxidation-reduction reaction with the metal substrate to obtain conductive ink.

[0046] (c) Remove the metal substrate obtained in (b) from the system, clean the surface with a small amount of deionized water, and prepare for subsequent use.

[0047] This invention enables the large-scale, green, and efficient preparation of graphene-based high-performance inks by adjusting the type of metal substrate, the composition of conductive agents, the concentration of graphene, and the concentration of conductive agents. Metal-doped graphene composite inks are obtained through in-situ reaction between the metal substrate and graphene. The functionality of the prepared inks is enhanced and their practicality optimized by utilizing different conductive agents.

[0048] In some embodiments, the metal substrate is mainly shaped as 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 of the metals selected from copper, iron, cobalt, nickel, zinc and tin.

[0049] In some embodiments, the graphene oxide is monolayer graphene oxide, oligolayer graphene oxide, or multilayer graphene oxide.

[0050] In some embodiments, the conductive agent is mainly one or a combination of carbon nanotubes, superconducting carbon black, rhodanine, polyvinylpyrrolidone (PVP), etc.

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

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

[0053] Example 1:

[0054] Immerse a 10cm×10cm nickel metal mesh in 6mol / L hydrochloric acid to remove the surface oxide layer, then clean it with acetone and finally with deionized water.

[0055] The metal mesh was placed in an aqueous solution of 0.1 mg / mL graphene oxide, 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 removed from the system, its surface is washed with deionized water, dried, and ready for reuse.

[0057] The resulting black ink is a reduced graphene oxide conductive ink loaded with nickel oxide.

[0058] The conductive ink prepared according to Example 1 is a black viscous liquid. The viscosity was tested to be 7.32 mPa·s and the sheet resistance was 680 Ω / sq.

[0059] Figure 2 The image shows a physical product of the reduced graphene oxide conductive ink loaded with nickel oxide as described in Example 1 of this invention. Viscosity and sheet resistance tests show that the conductive ink has relatively high viscosity and good conductivity.

[0060] Figure 3 This is a SEM image of the reduced graphene oxide conductive ink loaded with nickel oxide as described in Example 1 of this invention. Figure 4 This is a TEM image of the reduced graphene oxide conductive ink loaded with nickel oxide as described in Example 1 of this invention. The SEM image shows that the reduced graphene oxide retains the integrity of the graphene sheets, and the TEM image demonstrates that the ultrafine metal oxide nanoparticles are uniformly distributed on the graphene sheets.

[0061] The method for preparing metal-doped graphene oxide conductive ink according to the present invention involves mixing the above-mentioned components and then controlling the reaction time, temperature, concentration, etc., to form a compositionally controllable graphene-based high-performance ink. The operation steps of Examples 2-16 are as described in the examples above, and the viscosity and sheet resistance of the corresponding conductive inks 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 for Examples 1-16

[0063]

[0064]

[0065] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of this invention and its equivalents, this invention also intends to include these modifications and variations. The above-described embodiments are merely preferred embodiments provided to fully illustrate this invention, and their scope of protection is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this invention are all within the scope of protection of this invention.

Claims

1. A method for preparing a metal-doped graphene oxide conductive ink, characterized in that, The method involves immersing a metal substrate in an aqueous solution of graphene oxide, using graphene oxide as an oxidant and the metal substrate as a reducing agent. The abundant oxygen-containing groups provided by graphene oxide offer good adsorption sites for metal ions, thereby promoting the growth of metal nanoparticles and causing a redox reaction to obtain a reduced graphene oxide ink loaded with metal oxide particles. The metal substrate is made of nickel, iron, copper, cobalt, zinc or tin, or an alloy containing at least two of the metals selected from nickel, iron, copper, cobalt, zinc and tin; the concentration of graphene oxide in the aqueous solution is 0.1 mg / mL to 80 mg / mL; the redox reaction temperature is 25℃ to 80℃, and the reaction time is 8 to 24 h.

2. 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.

3. The method for preparing metal-doped graphene oxide conductive ink according to claim 1, characterized in that, The graphene oxide is a single-layer graphene oxide, an oligolayer graphene oxide, or a multilayer graphene oxide.

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

5. The method for preparing metal-doped graphene oxide conductive ink according to claim 4, characterized in that, The conductive agent is at least one of carbon nanotubes, superconducting carbon black, rhodanine, and polyvinylpyrrolidone.

6. The method for preparing the metal-doped graphene oxide conductive ink according to claim 4, characterized in that, The mass ratio of the graphene oxide to the conductive agent is (5~20):

1.

7. Reduced graphene oxide ink loaded with metal oxide particles prepared by the preparation method according to any one of claims 1-6.

8. The reduced graphene oxide ink loaded with metal oxide particles as described in claim 7 is used as a conductive ink for inkjet printing.

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