Preparation method of high-conductivity nano-silver wire transparent electrode

Abstract

The embodiment of the application discloses a preparation method of a high-conductivity nano-silver wire transparent electrode, and the preparation steps comprise the following steps: preparing a polycycloolefin modified degradable PVP, preparing nano-silver wire and preparing a high-conductivity nano-silver wire transparent electrode; a degradable PVP material is prepared by introducing a degradable chain segment into a PVP chain segment; the nano-silver wire is prepared by using the degradable PVP material and is coated on a base material to prepare a conductive electrode; the nano-silver wire on the electrode is purified by degrading the degradable chain segment and removing the PVP material by washing with a solvent, the conductivity and the transparency of the conductive electrode are increased, and the overall performance of the electrode is effectively improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of transparent electrodes, and in particular to a method for preparing a highly conductive nanosilver wire transparent electrode. Background Art

[0002] Currently, silver nanowires have become one of the ideal materials for making transparent conductive electrodes due to their excellent conductivity and flexibility. Silver nanowires usually have a diameter of tens to hundreds of nanometers and a length of several micrometers to tens of micrometers, which enables them to provide extremely low resistance and high transmittance when forming a network. Silver nanowires can be easily integrated onto different substrates to prepare transparent electrodes through printing, spraying or other deposition techniques. Transparent electrodes prepared from silver nanowires can achieve efficient current transmission and good optical properties while maintaining the flexibility and durability of the material. They have great applications in touch screens, flexible displays, solar panels, smart wearable devices and other fields.

[0003] During the synthesis of silver nanowires, polyvinylpyrrolidone (hereinafter referred to as PVP) is often used as a dispersant and stabilizer to prevent the silver nanowires from aggregating in the solution. PVP effectively stabilizes the size and shape of the silver wires by adsorbing on the surface of the silver wires, thereby maintaining their uniform distribution. However, when these silver nanowires are used to make transparent conductive electrodes, the presence of PVP will affect the performance of the final product. When the silver nanowires are coated on the substrate, PVP will also be coated, which may lead to an increase in the resistance of the electrode because PVP itself is not conductive. In addition, the presence of PVP may also affect the optical transparency and overall mechanical strength of the electrode. Therefore, although PVP plays a key role in the synthesis of silver nanowires, in subsequent applications, it may be necessary to remove or reduce PVP through appropriate post-processing steps, such as heat treatment or chemical treatment, to improve the overall performance of the electrode.

[0004] Due to the strong interaction between PVP and silver nanowires, simple washing or solvent treatment is difficult to completely remove PVP. Although high-temperature treatment can decompose PVP, this high temperature usually needs to be greater than 200°C, which may cause aggregation or morphological changes of silver nanowires, thereby affecting their conductive properties. Due to the difficulty of PVP removal and its potential impact on the performance of silver nanowires, there is currently relatively little research on this issue and a lack of systematic solutions. Therefore, developing more effective removal methods or finding new non-adhesive stabilizers is crucial to promoting the application of silver nanowires in advanced electronic technologies. Summary of the Invention

[0005] The main purpose of this invention is to provide a method for preparing a highly conductive, transparent silver nanowire electrode. By introducing degradable segments into PVP chains, a degradable PVP material is prepared. Silver nanowires are prepared using the degradable PVP material and then coated onto a substrate to form a conductive electrode. The degradation of the degradable segments and the removal of the PVP material by solvent washing enhance the conductivity and transparency of the conductive electrode.

[0006] In order to achieve the above object, a method for preparing a highly conductive nanosilver wire transparent electrode is provided according to the present invention, the method comprising the following steps:

[0007] Step S1: preparing polycycloolefin-modified degradable PVP;

[0008] A certain amount of cyclooctene is added to organic solvent A, stirred evenly under a nitrogen atmosphere, and the temperature is controlled at 20-50°C; a small amount of Grubbs catalyst and chain transfer agent is added, and the reaction is continued for 0.5-1 hour. The reactant is then poured into a large amount of methanol, and the bottom precipitate is collected and dried to obtain polycyclooctene;

[0009] A certain amount of polycyclooctene is added to organic solvent B, a small amount of azobisisobutyronitrile initiator is added, the temperature is raised to 40-80°C, and stirred under a nitrogen atmosphere to form a uniform polycycloolefin solution;

[0010] A certain amount of vinyl pyrrolidone is added to organic solvent C, and the mixture is stirred and mixed to obtain a vinyl pyrrolidone solution;

[0011] The vinyl pyrrolidone solution is added dropwise to the polycycloolefin solution for 1 hour. After the addition is completed, the reaction is continued for 1 to 2 hours. After washing and drying, the polycycloolefin-modified degradable PVP is obtained.

[0012] Step S2: preparing silver nanowires;

[0013] Take a certain amount of polycycloolefin-modified biodegradable PVP and add it to ethylene glycol, stirring to mix thoroughly. Raise the temperature to a certain level, drop a small amount of copper chloride and mix thoroughly. Slowly add the ethylene glycol solution of silver nitrate using a peristaltic pump. Continue the reaction for 1 hour after the addition is complete. Cool the reaction solution to room temperature, add anhydrous ethanol, and centrifuge and wash several times. Disperse the prepared silver nanowire dispersion in the ethanol solution for later use.

[0014] Step S3: preparing a highly conductive silver nanowire transparent electrode;

[0015] The prepared nano silver wire solution is sprayed on glass, heated to 50-100° C., and the glass surface is washed with an organic solvent D containing a Grubbs catalyst. After drying, a highly conductive nano silver wire transparent electrode is obtained.

[0016] Preferably, in step S1, the mass ratio of cyclooctene to organic solvent A is (10-20):100; the amount of Grubbs catalyst added is 0.01-1% of the mass of cyclooctene; the amount of chain transfer agent added is 0.1%-5% of the mass of cyclooctene; the mass ratio of polycyclooctene to organic solvent B is (10-30):100; the amount of azobisisobutyronitrile added is 1%-5% of the mass of polycyclooctene; the mass ratio of vinylpyrrolidone to organic solvent C is (10-30):100; and the mass ratio of vinylpyrrolidone to polycyclooctene is (50-200):100.

[0017] Preferably, the organic solvent A is any one or more combinations of dichloromethane, chloroform, tetrahydrofuran and toluene.

[0018] Preferably, the organic solvent B is any one or more combinations of toluene, dimethylformamide, dimethylacetamide and methylpyrrolidone.

[0019] Preferably, the organic solvent C is any one or more combinations of toluene, dimethylformamide, dimethylacetamide and methylpyrrolidone.

[0020] Preferably, the Grubbs catalyst is a ruthenium carbene complex and a modified ruthenium carbene complex, and the chain transfer agent is a thiol or boron hydride.

[0021] Preferably, in step S2, the mass ratio of the polycycloolefin-modified degradable PVP, ethylene glycol and copper chloride is (1-3):100:(0.01-0.1).

[0022] Preferably, in step S2, the concentration of the ethylene glycol solution of silver nitrate is 1-3 g / 100 ml, the addition amount is 100 ml, the addition time is 1-3 h, and the reaction temperature is 100-150° C.; the concentration of the silver nanowires dispersed in ethanol is 0.1-5 mg / ml.

[0023] Preferably, in step S3, the solubility of the Grubbs catalyst is 0.1-5%.

[0024] Preferably, the organic solvent D is any one or more combinations of dichloromethane, chloroform, tetrahydrofuran, toluene, dimethylformamide, dimethylacetamide and methylpyrrolidone.

[0025] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0026] The present invention prepares a degradable PVP material by introducing degradable segments into PVP chains. Nanosilver wires are prepared from the degradable PVP material and coated onto a substrate to form a conductive electrode. The PVP material is removed by degrading the degradable segments and washing with a solvent, thereby purifying the nanosilver wires on the electrode and enhancing the conductivity and transparency of the conductive electrode. DETAILED DESCRIPTION

[0027] The main purpose of this invention is to provide a method for preparing a highly conductive, transparent silver nanowire electrode. By introducing degradable segments into PVP chains, a degradable PVP material is prepared. Silver nanowires are prepared using the degradable PVP material and then coated onto a substrate to form a conductive electrode. The degradation of the degradable segments and the removal of the PVP material by solvent washing enhance the conductivity and transparency of the conductive electrode.

[0028] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention will be described in further detail below. It should be understood that the embodiments described herein are merely some, not all, of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments herein without inventive effort are intended to fall within the scope of protection of the present invention.

[0029] The present invention provides a method for preparing a highly conductive nanosilver wire transparent electrode, the method comprising the following steps:

[0030] Step S1: preparing polycycloolefin-modified degradable PVP;

[0031] A certain amount of cyclooctene is added to organic solvent A, stirred evenly under a nitrogen atmosphere, and the temperature is controlled at 20-50°C; a small amount of Grubbs catalyst and chain transfer agent is added, and the reaction is continued for 0.5-1 hour. The reactant is then poured into a large amount of methanol, and the bottom precipitate is collected and dried to obtain polycyclooctene;

[0032] A certain amount of polycyclooctene is added to organic solvent B, a small amount of azobisisobutyronitrile initiator is added, the temperature is raised to 40-80°C, and stirred under a nitrogen atmosphere to form a uniform polycycloolefin solution;

[0033] A certain amount of vinyl pyrrolidone is added to organic solvent C, and the mixture is stirred and mixed to obtain a vinyl pyrrolidone solution;

[0034] The vinyl pyrrolidone solution is added dropwise to the polycycloolefin solution for 1 hour. After the addition is completed, the reaction is continued for 1 to 2 hours. After washing and drying, the polycycloolefin-modified degradable PVP is obtained.

[0035] Step S2: Preparation of silver nanowires

[0036] Take a certain amount of polycycloolefin-modified biodegradable PVP and add it to ethylene glycol, stirring to mix thoroughly. Raise the temperature to a certain level, drop a small amount of copper chloride and mix thoroughly. Slowly add the ethylene glycol solution of silver nitrate using a peristaltic pump. Continue the reaction for 1 hour after the addition is complete. Cool the reaction solution to room temperature, add anhydrous ethanol, and centrifuge and wash several times. Disperse the prepared silver nanowire dispersion in the ethanol solution for later use.

[0037] Step S3: preparing a highly conductive silver nanowire transparent electrode;

[0038] The prepared nano silver wire solution is sprayed on glass, heated to 50-100° C., and the glass surface is washed with an organic solvent D containing a Grubbs catalyst. After drying, a highly conductive nano silver wire transparent electrode is obtained.

[0039] Preferably, in step S1, the mass ratio of cyclooctene to organic solvent A is (10-20):100; the amount of Grubbs catalyst added is 0.01-1% of the mass of cyclooctene; the amount of chain transfer agent added is 0.1%-5% of the mass of cyclooctene; the mass ratio of polycyclooctene to organic solvent B is (10-30):100; the amount of azobisisobutyronitrile added is 1%-5% of the mass of polycyclooctene; the mass ratio of vinylpyrrolidone to organic solvent C is (10-30):100; and the mass ratio of vinylpyrrolidone to polycyclooctene is (50-200):100.

[0040] Preferably, the organic solvent A is any one or more combinations of dichloromethane, chloroform, tetrahydrofuran and toluene.

[0041] Preferably, the organic solvent B is any one or more combinations of toluene, dimethylformamide, dimethylacetamide and methylpyrrolidone.

[0042] Preferably, the organic solvent C is any one or more combinations of toluene, dimethylformamide, dimethylacetamide and methylpyrrolidone.

[0043] Preferably, the Grubbs catalyst is a ruthenium carbene complex and a modified ruthenium carbene complex, and the chain transfer agent is a thiol or boron hydride.

[0044] Preferably, in step S2, the mass ratio of the polycycloolefin-modified degradable PVP, ethylene glycol and copper chloride is (1-3):100:(0.01-0.1).

[0045] Preferably, in step S2, the concentration of the ethylene glycol solution of silver nitrate is 1-3 g / 100 ml, the addition amount is 100 ml, the addition time is 1-3 h, and the reaction temperature is 100-150° C.; the concentration of the silver nanowires dispersed in ethanol is 0.1-5 mg / ml.

[0046] Preferably, in step S3, the solubility of the Grubbs catalyst is 0.1-5%.

[0047] Preferably, the organic solvent D is any one or more combinations of dichloromethane, chloroform, tetrahydrofuran, toluene, dimethylformamide, dimethylacetamide and methylpyrrolidone.

[0048] In the preparation of silver nanowires of the present invention, ethylene glycol, which functions as both a solvent and a reducing agent, is selected as a solvent because it has sufficient reducing ability, a high boiling point, and suitable viscosity. Cl- is selected as a controlling agent to react with Ag+ to generate insoluble silver halide, which reduces the reduction rate of silver and acts as a nucleating agent to provide initial crystallization sites. PVP, as a crystal surface protective agent, preferentially adsorbs on the {100} crystal planes on the sides of the silver nanocrystals, helping to inhibit the growth of the silver nanocrystals along the diameter direction, thereby inducing them to grow into silver nanowires along the {111} crystal planes along the longitudinal axis.

[0049] Cyclooctene is a cycloolefin capable of ring-opening metathesis polymerization (ROMP). ROMP is a chain-growth polymerization reaction that uses a transition metal catalyst to open the ring structure of a cycloolefin, forming a polymer chain containing double bonds. In the ROMP reaction of cyclooctene, a catalyst (such as a Grignard reagent or a metal carbene complex) inserts into the carbon-carbon double bond of the cyclooctene, breaking the ring structure and forming a reactive intermediate. This reactive intermediate then reacts with another cyclooctene molecule, further breaking the ring and inserting into the polymer chain, ultimately forming polycyclooctene.

[0050] A key characteristic of ROMP is its reversibility. This means that under appropriate conditions and with the same catalyst, polycyclooctene can undergo a reverse reaction—depolymerization—to reform cyclooctene monomer. This reversibility stems from the equilibrium nature of the ROMP reaction. When reaction conditions change, such as temperature or catalyst concentration, the equilibrium shifts in favor of either monomer or polymer. For example, increasing the temperature in the presence of a catalyst promotes the depolymerization of polycyclooctene, producing more cyclooctene monomer. This depolymerization temperature typically ranges from 50°C to 100°C.

[0051] The ring-opening metathesis polymerization and depolymerization of cyclooctene are as follows:

[0052]

[0053] The present invention prepares modified PVP by preparing polycyclooctene through ring-opening metathesis polymerization and then copolymerizing it with vinylpyrrolidone. Because the modified PVP contains depolymerizable polycyclooctene, it can be depolymerized into small molecular segments under heating. These small molecular segments can be easily removed with an organic solvent. Silver nanowires are prepared using the modified PVP and coated on a substrate to form a conductive electrode. The PVP is then removed to obtain a highly conductive conductive electrode.

[0054] The polymerization reaction of polycyclooctene and PVP is as follows:

[0055]

[0056] The degradation reaction of PVP is as follows:

[0057]

[0058] When Grubbs' catalyst is added and heated, the polycyclooctene segments in the modified PVP degrade into cyclooctene monomer and low-molecular-weight vinylpyrrolidone segments. These monomer and low-molecular-weight vinylpyrrolidone segments are easily removed by organic solvents. Using modified PVP to prepare silver nanowires and then removing the PVP from the conductive electrode significantly improves the conductivity and transparency of the conductive electrode.

[0059] The following six embodiments and four comparative examples are used to describe the present technical solution in detail:

[0060] Example 1

[0061] Preparation of biodegradable PVP: Add 10g of cyclooctene to 100g of chloroform and stir under a nitrogen atmosphere at 30°C. Add 0.05g of Grubbs' catalyst and 0.2g of mercaptan. Continue the reaction for 1 hour, then pour the mixture into a large amount of methanol. Collect the precipitate and dry it to obtain polycyclooctene. Add 20g of polycycloolefin to 100g of toluene and 0.6g of azobisisobutyronitrile as initiator. Raise the temperature to 60°C and stir under a nitrogen atmosphere to form a uniform polycycloolefin solution. Add 15g of vinylpyrrolidone to 100g of toluene and stir to mix. Add the vinylpyrrolidone solution dropwise to the polycycloolefin solution over 1 hour. Continue the reaction for 1 hour after the addition is complete. Wash and dry to obtain polycycloolefin-modified biodegradable PVP1.

[0062] Example 2

[0063] Preparation of a Highly Conductive Silver Nanowire Electrode: 1.5g of the degradable PVP from Example 1 was added to 100g of ethylene glycol and stirred to mix thoroughly. The temperature was raised to 160°C, 0.04g of copper chloride was added, and the mixture was thoroughly mixed. Using a peristaltic pump, 100ml of a 1g / 100ml silver nitrate solution in ethylene glycol was slowly added dropwise over 1 hour. The reaction mixture was allowed to react for 1 hour after addition. The reaction solution was cooled to room temperature, and anhydrous ethanol was added and centrifuged multiple times for washing. The prepared silver nanowires were dispersed in the ethanol solution to prepare a 1mg / ml dispersion. The silver nanowires were sprayed onto glass, heated to 60°C, and the glass surface was washed with 3% Grubbs catalyst in dimethylformamide. After drying, a highly conductive silver nanowire transparent electrode was obtained.

[0064] Example 3

[0065] Preparation of biodegradable PVP: Add 12g of cyclooctene to 100g of chloroform and stir under a nitrogen atmosphere at 35°C. Add 0.08g of Grubbs' catalyst and 0.3g of mercaptan. Continue the reaction for 1 hour, then pour the mixture into a large amount of methanol. The precipitate at the bottom is collected and dried to obtain polycyclooctene. Add 20g of polycycloolefin to 100g of dimethylformamide, add 0.4g of azobisisobutyronitrile as initiator, heat to 60°C, and stir under a nitrogen atmosphere to form a uniform polycycloolefin solution. Add 18g of vinylpyrrolidone to 100g of dimethylformamide and stir to mix. Add the vinylpyrrolidone solution dropwise to the polycycloolefin solution over 1 hour. After completion of the addition, continue the reaction for 1.5 hours. Wash and dry to obtain polycycloolefin-modified biodegradable PVP2.

[0066] Example 4

[0067] Preparation of a Highly Conductive Silver Nanowire Electrode: 1.8g of the degradable PVP from Example 3 was added to 100g of ethylene glycol and stirred to mix thoroughly. The temperature was raised to 170°C, and 0.06g of copper chloride was added and mixed thoroughly. Using a peristaltic pump, 100ml of a 1.5g / 100ml silver nitrate solution in ethylene glycol was slowly added dropwise over 1.5 hours. The reaction mixture was allowed to react for 1 hour after addition. The reaction solution was cooled to room temperature, and anhydrous ethanol was added and centrifuged multiple times for washing. The prepared silver nanowires were dispersed in the ethanol solution to prepare a dispersion with a concentration of 1.2mg / ml. The silver nanowires were sprayed onto glass, heated to 70°C, and the glass surface was washed with a 2% Grubbs catalyst solution in toluene. After drying, a highly conductive silver nanowire transparent electrode was obtained.

[0068] Example 5

[0069] Preparation of biodegradable PVP: Add 20g of cyclooctene to 100g of chloroform and stir under a nitrogen atmosphere at 35°C. Add 0.15g of Grubbs' catalyst and 0.2g of mercaptan. Continue the reaction for 1 hour, then pour the mixture into a large amount of methanol. The precipitate at the bottom is collected and dried to obtain polycyclooctene. Add 15g of polycycloolefin to 100g of methylpyrrolidone and 0.3g of azobisisobutyronitrile as initiator. Heat to 70°C and stir under a nitrogen atmosphere to form a uniform polycycloolefin solution. Add 20g of vinylpyrrolidone to 100g of methylpyrrolidone and stir to mix thoroughly. Add the vinylpyrrolidone solution dropwise to the polycycloolefin solution over 1 hour. Continue the reaction for 2 hours after the addition is complete. Wash and dry to obtain polycycloolefin-modified biodegradable PVP3.

[0070] Example 6

[0071] Preparation of a Highly Conductive Nanosilver Wire Electrode: 2g of the degradable PVP described in Example 5 was added to 100g of ethylene glycol and stirred to mix thoroughly. The temperature was raised to 160°C, 0.04g of copper chloride was added, and the mixture was mixed thoroughly. Using a peristaltic pump, 100ml of a 2g / 100ml silver nitrate solution in ethylene glycol was slowly added dropwise over 2 hours. The reaction mixture was allowed to react for 1 hour after addition. The reaction solution was cooled to room temperature, and anhydrous ethanol was added and centrifuged multiple times for washing. The prepared nanosilver wires were dispersed in the ethanol solution to prepare a dispersion with a concentration of 0.8mg / ml. The nanosilver wires were sprayed onto glass, heated to 80°C, and the glass surface was washed with a 3.5% Grubbs catalyst solution in methylpyrrolidone. After drying, a highly conductive transparent nanosilver wire electrode was obtained.

[0072] Comparative Example 1

[0073] Preparation of PVP: 100 g of vinyl pyrrolidone and 180 g of dimethylformamide were added to a three-necked flask, 3 g of initiator azobisisobutyronitrile was added, nitrogen was introduced and the temperature was raised to 65°C, and the reaction was continued for 3 h to obtain polyvinyl pyrrolidone, which was then dried to obtain PVP powder.

[0074] Comparative Example 2

[0075] Preparation of silver nanowires: Take 1.8g of the modified PVP from Comparative Example 1 and add it to 100g of ethylene glycol, stirring to mix thoroughly. Raise the temperature to 170°C, add 0.05g of cupric chloride and mix thoroughly. Use a peristaltic pump to slowly add 100ml of ethylene glycol solution with a concentration of 1g / 100ml silver nitrate over 1 hour. Continue the reaction for 1 hour after the addition is complete. Cool the reaction solution to room temperature, add anhydrous ethanol, and centrifuge and wash several times. Disperse the prepared silver nanowires in the ethanol solution to prepare a dispersion with a concentration of 1mg / ml. Spray the silver nanowires onto a glass film and dry to obtain a transparent electrode.

[0076] Comparative Example 3

[0077] Preparation of PVP: Add 100g of vinyl pyrrolidone and 140g of methyl pyrrolidone into a three-necked flask, add 1.5g of initiator azobisisobutyronitrile, introduce nitrogen and raise the temperature to 80°C, react for 1h to obtain polyvinyl pyrrolidone, and dry to obtain PVP powder.

[0078] Comparative Example 4

[0079] Preparation of silver nanowires: Take 1.5g of PVP from Comparative Example 3 and add it to 100g of ethylene glycol, stirring to mix thoroughly. Raise the temperature to 160°C, add 0.06g of copper chloride and mix thoroughly. Use a peristaltic pump to slowly add 100ml of ethylene glycol solution with a concentration of 1.7g / 100ml silver nitrate over 1.5 hours. Continue the reaction for 1 hour after the addition is complete. Cool the reaction solution to room temperature, add anhydrous ethanol and centrifuge and wash several times. Disperse the prepared silver nanowires in the ethanol solution to prepare a dispersion with a concentration of 1.4mg / ml. Spray the silver nanowires onto glass and dry to obtain a transparent electrode.

[0080] The molecular weight of the prepared polycyclooctene was tested by gel permeation chromatography (GPC), and the results were as follows:

[0081] Serial number Example 1 Example 3 Example 5 Molecular weight / Mn 2580 3520 5470

[0082] The molecular weight of the prepared polycyclooctene is between 2500 and 5500, and the molecular weight can be further increased by polymerization.

[0083] The molecular weight of the prepared degradable PVP was tested by gel permeation chromatography (GPC), and the results were as follows:

[0084]

[0085] The prepared degradable PVP has a molecular weight between 100,000 and 150,000 and can be used to prepare nanosilver wires.

[0086] The visible light transmittance of the transparent electrodes without removing the PVP in Examples 2, 4, and 6 was tested using a UV-visible spectrum scanning tester, and the results were as follows:

[0087] Serial number Example 2 Example 4 Example 6 Transmittance / % 90.4 89.8 89.6

[0088] The visible light transmittance of the prepared transparent electrode was tested using a UV-visible spectrum scanning tester, and the results are as follows:

[0089] Serial number Example 2 Example 4 Example 6 Comparative Example 2 Comparative Example 4 Transmittance / % 92.2 91.8 92.3 90.2 89.6

[0090] Transparent electrodes prepared with nano-silver wires all have good visible light transmittance. The transmittance of transparent electrodes containing PVP is around 90%, and the transmittance of transparent electrodes without PVP will increase to around 92%.

[0091] The sheet resistance of the transparent electrodes without removing the PVP in Examples 2, 4, and 6 was tested using a four-probe tester, and the results were as follows:

[0092] Serial number Example 2 Example 4 Example 6 Square resistance / Ω 10.7 11.5 9.3

[0093] The square resistance of the prepared transparent electrode was tested using a four-probe tester, and the results are as follows:

[0094]

[0095]

[0096] The square resistance of the transparent electrode prepared with PVP is between 9 and 11Ω, and the square resistance of the transparent electrode without PVP is between 4.3 and 5.2Ω. Removing PVP can effectively improve the conductivity of the prepared transparent electrode.

[0097] As can be seen from the above technical solution, the present invention prepares a degradable PVP material by introducing a degradable segment into the PVP chain. Nanosilver wires are prepared from the degradable PVP material and then coated onto a substrate to form a conductive electrode. The degradation of the degradable segment and the removal of the PVP material by solvent washing purify the nanosilver wires on the electrode, enhancing the conductivity and transparency of the conductive electrode.

[0098] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a highly conductive nanosilver wire transparent electrode, characterized in that: The method comprises the following steps: Step S1: preparing polycycloolefin-modified degradable PVP; A certain amount of cyclooctene is added to organic solvent A, stirred evenly under a nitrogen atmosphere, and the temperature is controlled at 20-50°C; a small amount of Grubbs catalyst and chain transfer agent is added, and the reaction is continued for 0.5-1 hour. The reactant is then poured into a large amount of methanol, and the bottom precipitate is collected and dried to obtain polycyclooctene; A certain amount of polycyclooctene is added to organic solvent B, a small amount of azobisisobutyronitrile initiator is added, the temperature is raised to 40-80°C, and stirred under a nitrogen atmosphere to form a uniform polycycloolefin solution; A certain amount of vinyl pyrrolidone is added to organic solvent C, and the mixture is stirred and mixed to obtain a vinyl pyrrolidone solution; The vinyl pyrrolidone solution is added dropwise to the polycycloolefin solution for 1 hour. After the addition is completed, the reaction is continued for 1 to 2 hours. After washing and drying, the polycycloolefin-modified degradable PVP is obtained. Step S2: preparing silver nanowires; A certain amount of polycycloolefin-modified biodegradable PVP was added to ethylene glycol, stirred and mixed evenly, and then heated to a certain temperature. A small amount of copper chloride was added dropwise and mixed evenly. The ethylene glycol solution of silver nitrate was slowly added using a peristaltic pump. After the addition was complete, the reaction was continued for 1 hour. The reaction solution was cooled to room temperature, anhydrous ethanol was added, and the solution was centrifuged and washed several times. The prepared nanosilver wire dispersion was dispersed in the ethanol solution for later use. Step S3: preparing a highly conductive silver nanowire transparent electrode; The prepared nano silver wire solution is sprayed on glass, heated to 50-100° C., and the glass surface is washed with an organic solvent D containing a Grubbs catalyst. After drying, a highly conductive nano silver wire transparent electrode is obtained.

2. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 1, wherein: In step S1, the mass ratio of cyclooctene to organic solvent A is (10-20):100; the amount of Grubbs catalyst added is 0.01-1% of the mass of cyclooctene; the amount of chain transfer agent added is 0.1%-5% of the mass of cyclooctene; the mass ratio of polycyclooctene to organic solvent B is (10-30):100; the amount of azobisisobutyronitrile added is 1%-5% of the mass of polycyclooctene; the mass ratio of vinyl pyrrolidone to organic solvent C is (10-30):100; and the mass ratio of vinyl pyrrolidone to polycyclooctene is (50-200):

100.

3. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 2, wherein: The organic solvent A is any one or more combinations of dichloromethane, chloroform, tetrahydrofuran and toluene.

4. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 2, wherein: The organic solvent B is any one or more combinations of toluene, dimethylformamide, dimethylacetamide and methyl pyrrolidone.

5. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 2, wherein: The organic solvent C is any one or more combinations of toluene, dimethylformamide, dimethylacetamide and methyl pyrrolidone.

6. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 2, wherein: The Grubbs catalyst is a ruthenium carbene complex and an improved ruthenium carbene complex, and the chain transfer agent is mercaptan or boron hydride.

7. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 1, wherein: In step S2, the mass ratio of polycycloolefin-modified degradable PVP, ethylene glycol and copper chloride is (1-3):100:(0.01-0.1).

8. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 7, wherein: In step S2, the concentration of silver nitrate in ethylene glycol solution is 1-3 g / 100 ml, the amount added is 100 ml, the addition time is 1-3 h, and the reaction temperature is 100-150° C.; the concentration of silver nanowires dispersed in ethanol is 0.1-5 mg / ml.

9. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 1, wherein: In step S3, the solubility of the Grubbs catalyst is 0.1-5%.

10. The method for preparing a highly conductive nano silver wire transparent electrode according to claim 9, wherein: The organic solvent D is any one or more combinations of dichloromethane, chloroform, tetrahydrofuran, toluene, dimethylformamide, dimethylacetamide and methyl pyrrolidone.

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