Paper-based electronic device and preparation method thereof

Abstract

The invention provides a paper-based electronic device and a preparation method thereof, and belongs to the technical field of flexible electronic device manufacturing. The acid solution is adopted for pretreatment, the acid solution can react with calcium carbonate in the cellulose paper to generate calcium oxalate and carbon dioxide gas, the impurity content is reduced, and the porosity of the paper can be increased; reducing reaction metal ions by adopting a reducing agent solution, embedding metal nanoparticles after reduction reaction into the cellulose fiber matrix, and taking the metal nanoparticles as a seed layer of chemical plating; the seed layer has the capability of adsorbing atomic active hydrogen (Hads), so that separation of the Hads in a metal salt solution is facilitated, the speed of reduction reaction of metal ions by the atomic active hydrogen is accelerated, and the conductive layer can be obtained; and laser engraving is adopted, environmental protection and no pollution are achieved, the processing speed is high, and the paper-based electronic device can be efficiently prepared in an environment-friendly mode.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible electronic device manufacturing, and in particular relates to a paper-based electronic device and a preparation method thereof. Background Art

[0002] The inherent characteristics of paper-based materials, such as low cost, portability, environmental protection and biodegradability, give them broad application prospects. Since paper itself is not conductive, metal graphic deposition technology is required to prepare electronic circuits on the surface of paper. Paper-based materials have the characteristics of rough surface, high temperature resistance, layered porosity and strong permeability. Traditional inkjet printing technology and screen printing graphic technology deposit metal externally, resulting in poor bonding strength between the conductive layer and the paper-based substrate. In addition, inkjet printing technology and screen printing graphic technology are inefficient, complicated to operate and not environmentally friendly. Therefore, how to achieve efficient and environmentally friendly preparation while ensuring the bonding strength between the conductive layer and the paper-based substrate in paper-based electronic devices has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0003] The object of the present invention is to provide a paper-based electronic device and a preparation method thereof. The preparation method provided by the present invention is efficient and environmentally friendly, and the conductive layer in the prepared paper-based electronic device has a high bonding strength with the paper-based substrate.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing a paper-based electronic device, comprising the following steps:

[0006] (1) soaking cellulose paper in an acidic solution for pretreatment to obtain pretreated cellulose paper;

[0007] (2) soaking the pretreated cellulose paper obtained in step (1) in a metal salt solution for adsorption to obtain cellulose paper adsorbed with metal ions;

[0008] (3) immersing the cellulose paper adsorbed with metal ions obtained in step (2) in a reducing agent solution to perform a reduction reaction, thereby obtaining a cellulose paper containing a seed layer;

[0009] (4) immersing the cellulose paper containing the seed layer obtained in step (3) in a chemical plating metal solution to perform a replacement reaction to obtain a cellulose paper containing a conductive layer;

[0010] (5) Laser engraving the cellulose paper containing the conductive layer obtained in step (4) to obtain a paper-based electronic device.

[0011] Preferably, in step (1), the pore size of the cellulose paper is 15-25 μm, and the thickness of the cellulose paper is 150-180 μm.

[0012] Preferably, the acidic solution in step (1) is oxalic acid or glacial acetic acid, and the concentration of the acidic solution is 200-500 mmol / L.

[0013] Preferably, the temperature of the pretreatment in step (1) is room temperature, and the time of the pretreatment is 5-10 min.

[0014] Preferably, the concentration of the metal salt solution in step (2) is 50-200 mmol / L.

[0015] Preferably, the temperature of the adsorption in step (2) is room temperature, and the time of the adsorption is 10-20 s.

[0016] Preferably, the concentration of the reducing agent solution in step (3) is 15-25 mmol / L.

[0017] Preferably, the temperature of the reduction reaction in step (3) is room temperature, and the time of the reduction reaction is 30-60 s.

[0018] Preferably, the power of the laser engraving in step (5) is 1-2 W, the rate of the laser engraving is 1000-2500 mm / min, and the focal length of the laser engraving is 22.5 mm.

[0019] The present invention also provides a paper-based electronic device prepared by the preparation method described in the above technical solution.

[0020] The present invention provides a preparation method of a paper-based electronic device, comprising the following steps: soaking cellulose paper in an acidic solution for pretreatment to obtain pretreated cellulose paper; soaking the pretreated cellulose paper in a metal salt solution for adsorption to obtain cellulose paper adsorbed with metal ions; soaking the cellulose paper adsorbed with metal ions in a reducing agent solution for a reduction reaction to obtain cellulose paper containing a seed layer; soaking the cellulose paper containing the seed layer in an electroless metal plating solution for a displacement reaction to obtain cellulose paper containing a conductive layer; and laser engraving the cellulose paper containing the conductive layer to obtain a paper-based electronic device. The present invention uses an acidic solution for pretreatment. The acidic solution can react with calcium carbonate in the cellulose paper to generate calcium oxalate and carbon dioxide gas, reduce the impurity content, thereby increasing the porosity of the paper, which is helpful for the preparation of the seed layer, enables metal ions to be better adsorbed on the cellulose paper, and increases the number of metal nanoparticles produced by the reduction reaction; then uses a reducing agent solution to reduce metal ions. The metal nanoparticles after the reduction reaction are embedded in the cellulose fiber matrix and serve as the seed layer for electroless plating; the seed layer has the ability to adsorb atomic hydrogen (H ads ) and is helpful for H in the metal salt solution adsSeparation enables the reduction reaction rate of metal ions by atomic hydrogen to accelerate, facilitating the formation of a conductive layer. Laser engraving is employed, which is environmentally friendly and pollution-free, with a fast processing speed, enabling the efficient and environmentally friendly preparation of paper-based electronic devices. The experimental results show that after nearly 12,000 bending cycles, the baseline resistance change rate of cellulose paper (without gold plating) containing a conductive layer is 60.4%, and the relative resistance change rate during a single bending cycle reaches 44.4%. After surface gold plating and after tens of thousands of bends, the baseline resistance change drops to 5.6%. This indicates that after tens of thousands of bending tests, the cellulose paper containing a conductive layer does not exhibit interlayer delamination and still maintains good flexibility and conductivity, demonstrating sufficient interfacial bonding strength. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the cellulose paper in Example 1;

[0022] Figure 2 It is a schematic diagram of the principle for preparing cellulose paper containing a seed layer in Example 1;

[0023] Figure 3 It is a schematic diagram of the reduction reaction using a sodium borohydride solution in Example 1;

[0024] Figure 4 It is a schematic structural diagram of nickel nanoparticles in the cellulose paper containing a seed layer in Example 1;

[0025] Figure 5 It is an SEM image of the surface of the cellulose paper containing a conductive layer in Example 1;

[0026] Figure 6 It is an SEM image of the surface of the cellulose paper modified with a gold film in Example 2;

[0027] Figure 7 It is the DES energy spectrum of the cellulose paper containing a conductive layer in Example 1 and the cellulose paper modified with a gold film in Example 2;

[0028] Figure 8 It is the XRD diffraction pattern of the cellulose paper containing a conductive layer in Example 1 and the cellulose paper modified with a gold film in Example 2;

[0029] Figure 9 It is an SEM image of the surface of a single paper fiber in the cellulose paper containing a conductive layer in Example 1 and the structural schematic diagram within the circle;

[0030] Figure 10 It is an SEM image of the surface of a single paper fiber in the cellulose paper modified with a gold film in Example 2 and the structural schematic diagram within the circle;

[0031] Figure 11The physical diagram of the change of cellulose paper during the preparation of the gold film in Example 2;

[0032] Figure 12 The change curve of the sheet resistance during the preparation of the cellulose paper containing a conductive layer and the cellulose paper modified with a gold film in Example 3 with the prolongation of the displacement reaction time;

[0033] Figure 13 The bending performance of the paper-based electronic devices prepared in Examples 4 to 7;

[0034] Figure 14 The electrochemical performance of the paper-based electronic devices prepared in Examples 4 to 7;

[0035] Figure 15 The polarization curve diagram of the paper-based electronic devices prepared in Examples 4 to 7;

[0036] Figure 16 The relationship curve between the resistance and temperature of the paper-based electronic device prepared in Example 8;

[0037] Figure 17 The relationship curve between the temperature coefficient of resistance and temperature of the paper-based electronic device prepared in Example 8;

[0038] Figure 18 The resistance change curve of the cellulose paper modified with a gold film in Example 9 and the cellulose paper containing a conductive layer in Example 10 during nearly 12,000 bending processes;

[0039] Figure 19 The process of the simple peeling experiment on the cellulose paper containing a conductive layer in Example 10;

[0040] Figure 20 The simple peeling result of the cellulose paper containing a conductive layer in Example 10;

[0041] Figure 21 The process of the simple peeling experiment on the cellulose paper containing a conductive layer in Example 11;

[0042] Figure 22 The simple peeling result of the cellulose paper containing a conductive layer in Example 11. Specific Embodiments

[0043] The present invention provides a preparation method of a paper-based electronic device, comprising the following steps:

[0044] (1) Immerse the cellulose paper in an acidic solution for pretreatment to obtain pretreated cellulose paper;

[0045] (2) Immerse the pretreated cellulose paper obtained in step (1) in a metal salt solution for adsorption to obtain a cellulose paper adsorbed with metal ions;

[0046] (3) Immerse the cellulose paper adsorbed with metal ions obtained in step (2) in a reducing agent solution for a reduction reaction to obtain a cellulose paper containing a seed layer;

[0047] (4) Immerse the cellulose paper containing a seed layer obtained in step (3) in an electroless metal plating solution for a displacement reaction to obtain a cellulose paper containing a conductive layer;

[0048] (5) Subject the cellulose paper containing a conductive layer obtained in step (4) to laser engraving to obtain a paper-based electronic device.

[0049] The present invention has no special limitation on the sources of each raw material, and commercially available products well-known to those skilled in the art can be used.

[0050] In the present invention, the cellulose paper is immersed in an acidic solution for pretreatment to obtain pretreated cellulose paper. The present invention uses an acidic solution for pretreatment. The acidic solution can react with calcium carbonate in the cellulose paper to generate calcium oxalate and carbon dioxide gas, reducing the impurity content, thereby increasing the porosity of the paper, which is helpful for the preparation of the seed layer, enabling metal ions to be better adsorbed on the cellulose paper, and increasing the number of metal nanoparticles produced by the reduction reaction.

[0051] In the present invention, the pore diameter of the cellulose paper is preferably 15 - 25 μm; the thickness of the cellulose paper is preferably 150 - 180 μm; the ash content in the cellulose paper is preferably 0.15 wt%. As an implementation manner, the thickness of the cellulose paper can be 160 - 170 μm. Limiting the pore diameter of the cellulose paper within the above range in the present invention is beneficial to the subsequent adsorption of metal ions.

[0052] As an implementation manner, the cellulose paper can be filter paper or A4 paper.

[0053] In the present invention, the acidic solution is preferably oxalic acid or glacial acetic acid; the concentration of the acidic solution is preferably 200 - 500 mmol / L. As an implementation manner, the concentration of the acidic solution can be 300 - 450 mmol / L, or can also be 400 mmol / L.

[0054] The present invention has no special limitation on the amount of the acidic solution used, as long as the cellulose paper can be immersed in the acidic solution.

[0055] The present invention has no special limitation on the operation of immersing the cellulose paper in the acidic solution, as long as the cellulose paper can be completely immersed in the acidic solution.

[0056] In the present invention, the temperature of the pretreatment is preferably room temperature; the time of the pretreatment is preferably 5 to 10 min. As an embodiment, the time of the pretreatment can be 6 to 9 min, or can also be 7 to 8 min. Limiting the temperature and time of the pretreatment within the above ranges in the present invention can further improve the effect of the pretreatment and further increase the porosity of the paper.

[0057] After the pretreatment is completed, the present invention preferably takes out the product obtained by the pretreatment from the acidic solution to obtain the pretreated cellulose paper.

[0058] The present invention has no special limitation on the operation of taking out, and the operation well-known to those skilled in the art can be adopted.

[0059] After obtaining the pretreated cellulose paper, the present invention soaks the pretreated cellulose paper in a metal salt solution for adsorption to obtain the cellulose paper adsorbed with metal ions.

[0060] In the present invention, before soaking the pretreated cellulose paper in the metal salt solution, the pretreated cellulose paper is preferably subjected to waxing treatment. The present invention has no special limitation on the operation of the waxing treatment, and it can be selected according to the requirements of single-sided or double-sided metal growth. In the present invention, the waxing treatment can inhibit the preparation of the seed layer on one side of the cellulose paper and control the growth area of the metal thin film; the wax is coated on the surface of the cellulose paper, and its interfacial bonding ability is poor. At the same time, the wax layer can be peeled off from the paper surface in blocks during the displacement reaction. Therefore, when the metal growth step is completed, only a small part of the wax layer remains on the surface of the fiber paper, and there is no need to worry about the influence of the wax layer on the subsequent treatment.

[0061] In the present invention, the concentration of the metal salt solution is preferably 50 to 200 mmol / L; the metal salt is preferably a nickel salt; the nickel salt is preferably nickel sulfate. As an embodiment, the concentration of the metal salt solution can be 100 to 150 mmol / L.

[0062] The present invention has no special limitation on the dosage of the metal salt solution, as long as the pretreated cellulose paper can be completely soaked.

[0063] The present invention has no special limitation on the operation of soaking the pretreated cellulose paper in the metal salt solution, as long as the pretreated cellulose paper can be completely soaked.

[0064] In the present invention, the temperature of the adsorption is preferably room temperature; the time of the adsorption is preferably 10 to 20 s. As an embodiment, the time of the adsorption can be 11 s, 12 s, 13 s, 14 s, 15 s, 16 s, 17 s, 18 s or 19 s. Limiting the temperature and time of the adsorption within the above ranges in the present invention can improve the adsorption effect.

[0065] After the adsorption is completed, the present invention preferably takes out the product obtained by adsorption from the metal salt solution, and then absorbs the excess solution on the surface with filter paper to obtain a cellulose paper adsorbed with metal ions.

[0066] The present invention has no special limitation on the operation of taking out, and the operations well-known to those skilled in the art can be adopted.

[0067] The present invention has no special limitation on the operation of absorbing the excess solution on the surface with filter paper, and the operations well-known to those skilled in the art can be adopted.

[0068] After obtaining the cellulose paper adsorbed with metal ions, the present invention immerses the cellulose paper adsorbed with metal ions in a reducing agent solution for a reduction reaction to obtain a cellulose paper containing a seed layer. The present invention prepares an environmentally friendly electroless plating seed layer based on the rapid ion exchange method.

[0069] In the present invention, the concentration of the reducing agent solution is preferably 15 - 25 mmol / L; the reducing agent is preferably sodium borohydride. As an embodiment, the concentration of the reducing agent solution can be 20 mmol / L.

[0070] The present invention has no special limitation on the dosage of the reducing agent solution, as long as the cellulose paper adsorbed with metal ions can be completely immersed.

[0071] The present invention has no special limitation on the operation of immersing the cellulose paper adsorbed with metal ions in the reducing agent solution, as long as the cellulose paper adsorbed with metal ions can be completely immersed.

[0072] In the present invention, the temperature of the reduction reaction is preferably room temperature; the time of the reduction reaction is preferably 30 - 60 s. As an embodiment, the time of the reduction reaction can be 35 s, 40 s, 45 s, 50 s or 55 s. The present invention limits the temperature and time of the reduction reaction within the above ranges to improve the degree of the reduction reaction.

[0073] After the reduction reaction is completed, the present invention preferably takes out the product obtained by the reduction reaction from the reducing agent solution, and then absorbs the excess solution on the surface with filter paper to obtain a cellulose paper containing a seed layer.

[0074] The present invention has no special limitation on the operation of taking out, and the operations well-known to those skilled in the art can be adopted.

[0075] The present invention has no special limitation on the operation of absorbing the excess solution on the surface with filter paper, and the operations well-known to those skilled in the art can be adopted.

[0076] In the present invention, the thickness of the seed layer is preferably 100 - 200 nm. As an embodiment, the thickness of the seed layer can be 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm or 190 nm.

[0077] After obtaining the cellulose paper containing the seed layer, the present invention immerses the cellulose paper containing the seed layer in an electroless metal plating solution for a displacement reaction to obtain a cellulose paper containing a conductive layer.

[0078] In the present invention, the electroless metal plating solution is preferably an electroless nickel plating solution; the components of the electroless nickel plating solution preferably include 1 - 2 g / L nickel sulfate (NiSO4), 0.2 - 0.5 g / L reducing agent and water; the reducing agent is preferably sodium hypophosphite (NaH2PO2). As an embodiment, the concentration of sodium sulfate can be 1.5 g / L; the concentration of the reducing agent can be 0.3 g / L or 0.4 g / L.

[0079] The present invention has no special limitation on the amount of the electroless metal plating solution, as long as the cellulose paper containing the seed layer is completely immersed.

[0080] The present invention has no special limitation on the operation of immersing the cellulose paper containing the seed layer in the electroless metal plating solution, as long as the cellulose paper containing the seed layer is completely immersed.

[0081] In the present invention, the temperature of the displacement reaction is preferably 80 - 100 °C; the time of the displacement reaction is preferably 15 - 30 min. As an embodiment, the temperature of the displacement reaction can be 85 - 95 °C, and can also be 90 °C; the time of the displacement reaction can be 20 - 25 min. The present invention limits the temperature and time of the displacement reaction within the above ranges, which is beneficial to obtaining a conductive layer.

[0082] After the displacement reaction is completed, the present invention preferably takes out the product obtained from the displacement reaction from the electroless metal plating solution to obtain a cellulose paper containing a conductive layer.

[0083] The present invention has no special limitation on the taking-out operation, and the operations well-known to those skilled in the art can be adopted.

[0084] In the present invention, the thickness of the conductive layer is preferably 5 - 10 μm. As an embodiment, the thickness of the conductive layer can be 6 μm, 7 μm, 8 μm or 9 μm.

[0085] After obtaining the cellulose paper containing the conductive layer, the present invention subjects the cellulose paper containing the conductive layer to laser engraving to obtain a paper-based electronic device.

[0086] In the present invention, preferably before laser engraving, it further includes soaking the cellulose paper containing a conductive layer in a chemical gold plating solution to carry out a displacement reaction to obtain a cellulose paper modified with a gold film, then taking it out, and then drying it or directly drying the cellulose paper containing a conductive layer. By soaking the cellulose paper containing a conductive layer in the chemical gold plating solution in the present invention, the surface of the cellulose paper containing a conductive layer can be modified by gold nanoparticles, improving the conductivity.

[0087] In the present invention, the chemical gold plating solution is preferably a cyanide-free electroless gold plating solution. The present invention has no special limitation on the type of the chemical gold plating solution, and a chemical gold plating solution well-known to those skilled in the art can be used.

[0088] As an embodiment, the manufacturer of the chemical gold plating solution can be Coslin Electroplating Instruments.

[0089] The present invention has no special limitation on the dosage of the chemical gold plating solution, as long as the cellulose paper containing a conductive layer is completely soaked.

[0090] In the present invention, the temperature of the displacement reaction is preferably 80 - 100 °C; the time of the displacement reaction is preferably 5 - 20 min. As an embodiment, the temperature of the displacement reaction can be 85 - 95 °C, and can also be 90 °C; the time of the displacement reaction can be 10 - 15 min. Limiting the temperature and time of the displacement reaction within the above ranges in the present invention is beneficial to obtaining a gold film, thereby being beneficial to improving the conductivity.

[0091] In the present invention, the thickness of the gold film is preferably 100 - 200 nm. As an embodiment, the thickness of the gold film can be 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm or 190 nm.

[0092] The present invention has no special limitation on the operation of taking out, and an operation well-known to those skilled in the art can be used.

[0093] In the present invention, the drying is preferably carried out under sealed conditions. The present invention has no special limitation on the temperature and time of the drying, and it is sufficient to dry to constant weight. Drying under sealed conditions in the present invention can avoid excessive contact between the gold film and air, resulting in the formation of an oxide layer on the surface and reducing its conductivity.

[0094] In the present invention, the power of the laser engraving is preferably 1 - 2 W; the rate of the laser engraving is preferably 1000 - 2500 mm / min; the focal length of the laser engraving is preferably 22.5 mm. As an embodiment, the rate of the laser engraving can be 1500 - 2000 mm / min.

[0095] The present invention has no special limitation on the circuit of the laser engraving, and it can be adjusted according to actual needs.

[0096] The present invention uses laser engraving to achieve the goal of metal patterning, which has the characteristics of environmental protection and no pollution, wide range of applicable materials, high precision, non-contact processing, fast processing speed and no heat affected zone, etc. It can efficiently and three-dimensionally control the conductive area, facilitating the manufacture of circuits and devices.

[0097] Based on the in-situ metal growth technology, the present invention grows a metal thin film in-situ on the cellulose paper, improving the interfacial bonding strength, making the cellulose paper denser. The porous and highly permeable cellulose paper is more conducive to the bonding of the metal thin film. And it uses laser engraving to simply and quickly manufacture electronic devices, which can achieve the characteristics of convenience, speed, environmental protection and mass production while ensuring the bonding strength between the conductive layer and the cellulose paper; the surface of the cellulose paper containing the conductive layer is rough, and laser engraving can smoothly and quickly engrave the metal thin film on it to form circuits or devices, and at the same time integrate the highly customizable characteristics of laser engraving into the device manufacturing.

[0098] In the preparation method provided by the present invention, the whole process is solution immersion, with extremely low requirements for the preparation environment. Different from the traditional electroless plating method, no additional surface modifiers such as strong oxidants, strong alkalis and noble metal catalysts are required. That is, the addition of the seed layer not only ensures the environmental protection characteristics of the paper-based material, but also improves the efficiency and simplicity of electroless metal growth, while also saving the cost of materials and subsequent waste treatment; using laser engraving as the patterning process takes into account requirements such as process compatibility, environmental protection, low cost and simplicity and high efficiency. In short, the present invention has improved the manufacturing process of paper-based flexible devices, and has the characteristics of green environmental protection, simplicity, high efficiency, low cost and batchability.

[0099] In the cellulose paper containing the conductive layer obtained by the preparation method provided by the present invention, a natural interlocking structure similar to tree roots is formed at the interface between the conductive layer and the cellulose paper. This structure penetrates into the interlayers of the paper. Laser engraving can achieve changes in the engraving depth by controlling parameters, and can efficiently and three-dimensionally control the conductive area, facilitating the manufacture of circuits and devices.

[0100] The present invention also provides a paper-based electronic device prepared by the preparation method described in the above technical solution.

[0101] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0102] Example 1

[0103] A preparation method of a paper-based electronic device comprises the following steps:

[0104] (1) Immerse the cellulose paper in an acidic solution and perform pretreatment at room temperature for 5 min, then take it out to obtain the pretreated cellulose paper; wherein, the pore diameter of the cellulose paper is 15 - 25 μm, the thickness is 150 μm, and the ash content is 0.15 wt%; the cellulose paper is A4 paper; the acidic solution is oxalic acid; the concentration of the acidic solution is 200 mmol / L;

[0105] (2) Immerse the pretreated cellulose paper obtained in step (1) in a 100 mmol / L nickel sulfate solution and perform adsorption at room temperature for 10 s, then take it out and absorb the excess solution on the surface with filter paper to obtain the cellulose paper adsorbed with metal ions;

[0106] (3) Immerse the cellulose paper adsorbed with metal ions obtained in step (2) in a 25 mmol / L sodium borohydride solution and perform a reduction reaction at room temperature for 30 s, then take it out and absorb the excess solution on the surface with filter paper to obtain the cellulose paper with a 150 - nm - thick seed layer;

[0107] (4) Immerse the cellulose paper with the seed layer obtained in step (3) in an electroless nickel plating solution and perform a displacement reaction at 90 °C for 15 min, then take it out to obtain the cellulose paper with a 5 - μm - thick conductive layer; wherein, the components of the electroless nickel plating solution are 2 g / L nickel sulfate, 0.5 g / L sodium hypophosphite and water;

[0108] (5) Dry the cellulose paper with the conductive layer obtained in step (4) under sealed conditions, and then perform laser engraving to obtain the paper-based electronic device; wherein, the power of the laser engraving is 1 W, the rate is 1500 mm / min, and the focal length is 22.5 mm.

[0109] Example 2

[0110] On the basis of Example 1, only modify step (5) to immerse the cellulose paper with the conductive layer obtained in step (4) in an electroless gold plating solution and perform a displacement reaction at 90 °C for 15 min to obtain the cellulose paper modified with a gold film, then take it out, and then dry it under sealed conditions, and finally perform laser engraving to obtain the paper-based electronic device; wherein, the manufacturer of the electroless gold plating solution is Coslin Electroplating Instrument; the power of the laser engraving is 1 W, the rate is 1500 mm / min, and the focal length is 22.5 mm; the thickness of the gold film is 150 nm.

[0111] The structural schematic diagram of the cellulose paper in Example 1 is as Figure 1 shown; the schematic principle diagram of preparing the cellulose paper with the seed layer in Example 1 is as Figure 2As shown; the schematic diagram of the reduction reaction using sodium borohydride solution in Example 1 is as follows Figure 3 As shown; the schematic diagram of the structure of nickel nanoparticles in the cellulose paper containing a seed layer in Example 1 is as follows Figure 4 As shown.

[0112] The equations of the reduction reaction using sodium borohydride solution in Example 1 are as shown in Formula I and Formula II:

[0113]

[0114] From Figure 1 It can be seen that the structure of the cellulose paper is formed by bonding a cellulose network pressed by a large amount of cellulose and residues generated during the papermaking process; it has a porous surface and a certain particle adsorption capacity. It shows that the cellulose paper can be used as a natural carrier for solutions and ions, and the solutions and ions can freely communicate with the outside through the network woven by the cellulose paper and the micropores on the surface. These characteristics provide good feasibility for the in-situ metal growth of the present invention.

[0115] From Figures 2 - 4 It can be seen that the formation of the seed layer mainly depends on the ability of the pores on the surface of the cellulose paper to adsorb nanoparticles.

[0116] The SEM image of the surface of the cellulose paper containing a conductive layer in Example 1 is as follows Figure 5 As shown; the SEM image of the surface of the cellulose paper modified with a gold film in Example 2 is as follows Figure 6 As shown; the DES energy spectrum of the cellulose paper containing a conductive layer in Example 1 and the cellulose paper modified with a gold film in Example 2 is as follows Figure 7 As shown; the XRD diffraction pattern of the cellulose paper containing a conductive layer in Example 1 and the cellulose paper modified with a gold film in Example 2 is as follows Figure 8 As shown ( Figure 7 and Figure 8 in which EN is the cellulose paper containing a conductive layer in Example 1; EN / Au is the cellulose paper modified with a gold film in Example 2).

[0117] From Figures 5 - 6 It can be seen that the metal particles (nickel or nickel and gold) of the present invention are deposited in the network channels constructed by the cellulose paper, obtaining a natural interlocking structure similar to tree roots on the interface.

[0118] From Figures 7 - 8 It can be seen that the main components of the conductive layer are metal nickel and gold.

[0119] The SEM image of the surface of a single paper fiber in the cellulose paper containing a conductive layer in Example 1 and the schematic diagram of the structure within the circle are as follows Figure 9 As shown; the SEM image of the surface of a single paper fiber in the cellulose paper modified with a gold film in Example 2 and the schematic diagram of the structure within the circle are as followsFigure 10 As shown in; The physical diagram of the change of cellulose paper when preparing the gold film in Example 2 is as Figure 11 shown.

[0120] From Figure 9 it can be seen that the nickel nanoparticles in the cellulose pores are distributed relatively loosely, resulting in incomplete joining between the deposited nanoparticle clusters and there are certain cracks; From Figure 10 it can be seen that through gold plating, denser gold nanoparticles cover the surface of the nickel layer; At the same time, the gold nanoparticles fill into the cracks between the nickel-plated clusters, bridging the originally non-conductive nickel-plated clusters together, further improving the conductivity of the cellulose paper.

[0121] From Figure 11 it can be seen that as the replacement reaction time increases, the metal layer becomes denser under the influence of gold nanoparticles and the color gradually deepens.

[0122] Example 3

[0123] A preparation method of a paper-based electronic device, which is the following steps:

[0124] (1) Immerse the cellulose paper in an acidic solution and perform pretreatment at room temperature for 5 min, then take it out to obtain pretreated cellulose paper; wherein, the pore diameter of the cellulose paper is 15 - 25 μm, the thickness is 150 μm, and the ash content is 0.15 wt%; the cellulose paper is A4 paper; the acidic solution is oxalic acid; the concentration of the acidic solution is 200 mmol / L;

[0125] (2) Immerse the pretreated cellulose paper obtained in step (1) in a 200 mmol / L nickel sulfate solution and perform adsorption at room temperature for 20 s, then take it out and absorb the excess solution on the surface with filter paper to obtain cellulose paper adsorbed with metal ions;

[0126] (3) Immerse the cellulose paper adsorbed with metal ions obtained in step (2) in a 25 mmol / L sodium borohydride solution and perform a reduction reaction at room temperature for 60 s, then take it out and absorb the excess solution on the surface with filter paper to obtain cellulose paper with a 150 nm thick seed layer;

[0127] (4) Immerse the cellulose paper with a seed layer obtained in step (3) in an electroless nickel plating solution and perform a replacement reaction at 90 °C for 15 min, then take it out to obtain cellulose paper with a 5 μm thick conductive layer; wherein, the components of the electroless nickel plating solution are 2 g / L nickel sulfate, 0.5 g / L sodium hypophosphite and water;

[0128] (5) Immerse the cellulose paper with the conductive layer obtained in step (4) in a chemical gold plating solution, carry out a displacement reaction at 90 °C for 20 min to obtain cellulose paper modified with a gold film with a thickness of 190 nm, then take it out, and then dry it under sealed conditions, and finally carry out laser engraving to obtain a paper-based electronic device; among them, the manufacturer of the chemical gold plating solution is Coslin Electroplating Instrument; the power of laser engraving is 1 W, the rate is 1500 mm / min, and the focal length is 22.5 mm.

[0129] During the preparation of cellulose paper with a conductive layer (electroless nickel plating layer) and cellulose paper modified with a gold film (chemical gold plating layer) in Example 3, the change curve of the surface resistance with the extension of the displacement reaction time is as Figure 12 shown.

[0130] From Figure 12 it can be seen that as the displacement reaction time increases, the surface resistance of the cellulose paper gradually decreases.

[0131] Example 4

[0132] On the basis of Example 3, the gold film modification is omitted, and other conditions remain unchanged, denoted as EN 15 min.

[0133] Example 5

[0134] On the basis of Example 3, the displacement reaction time in step (5) is modified to 5 min, the thickness of the gold film is 110 nm, and other conditions remain unchanged, denoted as EN 15 min + Au 5 min.

[0135] Example 6

[0136] On the basis of Example 3, the displacement reaction time in step (5) is modified to 10 min, the thickness of the gold film is 130 nm, and other conditions remain unchanged, denoted as EN 15 min + Au 10 min.

[0137] Example 7

[0138] On the basis of Example 3, the displacement reaction time in step (5) is modified to 15 min, the thickness of the gold film is 150 nm, and other conditions remain unchanged, denoted as EN 15 min + Au 15 min.

[0139] Under the long-term programmed reciprocating strain test of 5750 s (cycle of 2.5 s), the bending performance of the paper-based electronic devices prepared in Examples 4 to 7 for 2300 times is as Figure 13 shown; under the programmed reciprocating strain test of the paper-based electronic devices prepared in Examples 4 to 7 within 50 s, the bending performance is as Figure 14 shown.

[0140] FromFigure 13 It can be seen that during the long-term test of 5750 s, the benchmark resistance change rates of the paper-based electronic devices prepared in Examples 4 to 7 are 8.0%, 2.0%, 1.7%, and 2.6% respectively.

[0141] From Figure 14 It can be seen that in the bending test curves intercepted from 4000 s to 4050 s, the relative resistance change rates of the paper-based electronic devices prepared in Examples 4 to 7 are stable at 7.6%, 3.9%, 2.2%, and 2.3% respectively.

[0142] In summary, in terms of mechanical stability, preparing the gold film with a replacement time exceeding 10 min basically meets the usage requirements of flexible wires.

[0143] The paper-based electronic devices prepared in Examples 4 to 7 were tested by electrochemical Tafel test, and the scanning speed was 0.01 V·s -1 , and the results are as Figure 15 shown; Figure 15 It is the polarization curve diagram of the paper-based electronic devices prepared in Examples 4 to 7.

[0144] From Figure 15 It can be seen that as the replacement gold time increases, the peaks of the polarization curves of the paper-based electronic devices at a scanning speed of 0.01 V·s -1 gradually move left and down, the corrosion resistance potential rises, and the corrosion resistance performance of the paper-based electronic devices is improved.

[0145] Therefore, the gold nanoparticles can obtain the best mechanical stability and chemical corrosion resistance when the replacement reaction time is 15 min, indicating its potential to act as a deformation sensor and working stability in different environments.

[0146] Example 8

[0147] A preparation method of a paper-based electronic device, comprising the following steps:

[0148] (1) Immerse the cellulose paper in an acidic solution and perform pretreatment at room temperature for 5 min, then take it out to obtain the pretreated cellulose paper; wherein, the pore diameter of the cellulose paper is 15 - 25 μm, the thickness is 150 μm, and the ash content is 0.15 wt%; the cellulose paper is A4 paper; the acidic solution is oxalic acid; the concentration of the acidic solution is 200 mmol / L;

[0149] (2) Immerse the pretreated cellulose paper obtained in step (1) in a 200 mmol / L nickel sulfate solution and perform adsorption at room temperature for 20 s, then take it out and absorb the excess solution on the surface with filter paper to obtain the cellulose paper adsorbed with metal ions;

[0150] (3) Immerse the cellulose paper adsorbed with metal ions obtained in step (2) in a 25 mmol / L sodium borohydride solution, carry out a reduction reaction at room temperature for 60 s, take it out and absorb the excess solution on the surface with filter paper to obtain a cellulose paper with a 150-nm-thick seed layer;

[0151] (4) Immerse the cellulose paper with the seed layer obtained in step (3) in an electroless nickel plating solution, carry out a displacement reaction at 90 °C for 15 min, take it out to obtain a cellulose paper with a 5-μm-thick conductive layer; wherein, the components of the electroless nickel plating solution are 2 g / L nickel sulfate, 0.5 g / L sodium hypophosphite and water;

[0152] (5) Immerse the cellulose paper with the conductive layer obtained in step (4) in an electroless gold plating solution, carry out a displacement reaction at 90 °C for 15 min to obtain a cellulose paper modified with a 150-nm-thick gold film, then take it out, dry it under sealed conditions, and finally carry out laser engraving to obtain a paper-based electronic device; wherein, the manufacturer of the electroless gold plating solution is Coslin Electroplating Instrument; the power of laser engraving is 1 W, the rate is 1500 mm / min, and the focal length is 22.5 mm.

[0153] The relationship curve between the resistance and temperature of the paper-based electronic device prepared in Example 8 is as Figure 16 shown; the relationship curve between the temperature coefficient of resistance (TCR) and temperature of the paper-based electronic device prepared in Example 8 is as Figure 17 shown.

[0154] From Figures 16 - 17 it can be seen that through graphic engraving, the paper-based electronic device can have a certain temperature measurement function.

[0155] Example 9

[0156] A preparation method of a paper-based electronic device, comprising the following steps:

[0157] (1) Immerse the cellulose paper in an acidic solution, carry out a pretreatment at room temperature for 5 min, take it out to obtain a pretreated cellulose paper; wherein, the pore size of the cellulose paper is 15-25 μm, the thickness is 150 μm, and the ash content is 0.15 wt%; the cellulose paper is A4 paper; the acidic solution is oxalic acid; the concentration of the acidic solution is 200 mmol / L;

[0158] (2) Immerse the pretreated cellulose paper obtained in step (1) in a 200 mmol / L nickel sulfate solution, carry out an adsorption at room temperature for 20 s, take it out and absorb the excess solution on the surface with filter paper to obtain a cellulose paper adsorbed with metal ions;

[0159] (3) Immerse the cellulose paper adsorbed with metal ions obtained in step (2) in a 25 mmol / L sodium borohydride solution, carry out a reduction reaction at room temperature for 60 s, take it out and absorb the excess solution on the surface with filter paper to obtain a cellulose paper with a 150-nm-thick seed layer;

[0160] (4) Immerse the cellulose paper with the seed layer obtained in step (3) in an electroless nickel plating solution, carry out a displacement reaction at 90 °C for 15 min, take it out to obtain a cellulose paper with a 5-μm-thick conductive layer; wherein, the electroless nickel plating solution consists of 2 g / L nickel sulfate, 0.5 g / L sodium hypophosphite and water;

[0161] (5) Immerse the cellulose paper with the conductive layer obtained in step (4) in an electroless gold plating solution, carry out a displacement reaction at 90 °C for 10 min to obtain a cellulose paper modified with a 130-nm-thick gold film, then take it out, and then dry it under sealed conditions, and finally carry out laser engraving to obtain a paper-based electronic device, denoted as EN 15min+Au 10min; wherein, the manufacturer of the electroless gold plating solution is Coslin Electroplating Instrument; the power of laser engraving is 1 W, the rate is 1500 mm / min, and the focal length is 22.5 mm.

[0162] Example 10

[0163] On the basis of Example 9, omit the gold film modification, keep other conditions unchanged, and obtain a paper-based electronic device, denoted as EN15min.

[0164] The resistance change curves of the cellulose paper modified with a gold film in Example 9 and the cellulose paper with a conductive layer in Example 10 during the bending process of nearly 12,000 times (total duration 31,200 s, single bending cycle 2.5 s) are as Figure 18 shown.

[0165] From Figure 18 it can be seen that after 12,000 bending cycles, the reference resistance change rate of the cellulose paper with a conductive layer in Example 10 is 60.4%, and the relative resistance change rate in a single bending cycle reaches 44.4%; after 12,000 bends of the cellulose paper modified with a gold film in Example 9, its reference resistance change rate is only 5.6%, and the relative resistance change rate in a single bending cycle reaches 16.7%. This means that retaining the microfiber structure on the surface of the cellulose filter paper can ensure the conductivity of the metallized fiber paper while enabling it to obtain higher anti-bending ability; it also shows that after tens of thousands of bending tests, neither the cellulose paper with a conductive layer in Example 10 nor the cellulose paper modified with a gold film in Example 9 shows interlayer peeling, and still maintains good flexibility and conductivity, indicating that it has sufficient interfacial bonding strength.

[0166] Example 11

[0167] On the basis of Example 10, wax is applied on one side before soaking in step (2), and other conditions remain unchanged.

[0168] A simple peeling experiment is carried out on the cellulose paper containing a conductive layer in Examples 10 and 11 by using tape, and the results are as Figures 19 - 22 shown.

[0169] Figure 19 is the process of the simple peeling experiment for the cellulose paper containing a conductive layer in Example 10; Figure 20 is the simple peeling result of the cellulose paper containing a conductive layer in Example 10; Figure 21 is the process of the simple peeling experiment for the cellulose paper containing a conductive layer in Example 11; Figure 22 is the simple peeling result of the cellulose paper containing a conductive layer in Example 11.

[0170] From Figures 19 - 22 it can be seen that only a little fiber capillary can be adhered by tearing the tape, indicating that the surface metal layer of the cellulose paper containing a conductive layer is firm and dense; when peeling from the bonding part, it can be clearly seen that part of the paper fiber layer and the metal layer are firmly bonded, and even if the paper fiber layer is split and peeled, the metal layer will not fall off alone.

[0171] From the above examples, it can be seen that the preparation method provided by the present invention is efficient, environmentally friendly, and the bonding strength between the conductive layer and the paper substrate in the prepared paper-based electronic device is high.

[0172] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a paper-based electronic device, comprising the following steps: (1) Immerse cellulose paper in an acidic solution for pretreatment to obtain pretreated cellulose paper; (2) Immerse the pretreated cellulose paper obtained in step (1) in a metal salt solution for adsorption to obtain cellulose paper adsorbed with metal ions; (3) Immerse the cellulose paper adsorbed with metal ions obtained in step (2) in a reducing agent solution for a reduction reaction to obtain cellulose paper containing a seed layer; (4) Immerse the cellulose paper containing a seed layer obtained in step (3) in an electroless metal plating solution for a displacement reaction to obtain cellulose paper containing a conductive layer; (5) Subject the cellulose paper containing a conductive layer obtained in step (4) to laser engraving to obtain a paper-based electronic device.

2. The preparation method according to claim 1, characterized in that, In step (1), the pore diameter of the cellulose paper is 15 - 25 μm, and the thickness of the cellulose paper is 150 - 180 μm.

3. The preparation method according to claim 1, characterized in that, The acidic solution in step (1) is oxalic acid or glacial acetic acid, and the concentration of the acidic solution is 200 - 500 mmol / L.

4. The preparation method according to claim 1, characterized in that, In step (1), the pretreatment temperature is room temperature, and the pretreatment time is 5 - 10 min.

5. The preparation method according to claim 1, characterized in that, In step (2), the concentration of the metal salt solution is 50 - 200 mmol / L.

6. The preparation method according to claim 1, wherein In step (2), the adsorption temperature is room temperature, and the adsorption time is 10 - 20 s.

7. The preparation method according to claim 1, characterized in that, In step (3), the concentration of the reducing agent solution is 15 - 25 mmol / L.

8. The preparation method according to claim 1, wherein In step (3), the reduction reaction temperature is room temperature, and the reduction reaction time is 30 - 60 s.

9. The preparation method according to claim 1, wherein In step (5), the laser engraving power is 1 - 2 W, the laser engraving rate is 1000 - 2500 mm / min, and the laser engraving focal length is 22.5 mm.

10. A paper-based electronic device prepared by the preparation method according to any one of claims 1 - 9.

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