WO2021232648A1

WO2021232648A1 - Device for macro-purifying metal-based nanowire

Info

Publication number: WO2021232648A1
Application number: PCT/CN2020/117146
Authority: WO
Inventors: 唐宏浩; 叶怀宇; 张国旗
Original assignee: 深圳第三代半导体研究院
Priority date: 2020-05-22
Filing date: 2020-09-23
Publication date: 2021-11-25
Also published as: CN212857762U

Abstract

A device for macro-purifying a metal-based nanowire, comprising a dynamic stirring and centrifugal filtering device, wherein the dynamic stirring and centrifugal filtering device comprises: a solution injection system, a filtering cylinder and a filtrate outflow system. The filtering cylinder comprises a filtering framework, a stirring device and a filtering membrane, wherein the filtering membrane sequentially comprises, in a perpendicular direction, a first filtering region, a second filtering region and a third filtering region; an inward included angle between any two of the first filtering region, the second filtering region and the third filtering region is less than 180 degrees; and a plurality of filtering holes are provided on the first filtering region, the second filtering region and the third filtering region. The device basically solves the core problems of tedious steps, a complex process, high costs, etc. suffered during industrial preparation and a purification post-treatment of a metal-based nanowire at present.

Description

Device for macro-purifying metal-based nanowires

Technical field

The utility model relates to the field of nano-material preparation, in particular to a device for macro-purifying metal-based nanowires.

Background technique

In recent years, the application of flexible transparent electrodes in wearable, flexible, and translucent electronic products and devices has attracted more and more attention, and its application range covers sensors, touch screens, artificial skin, transistors, and optical displays. The reason for this attention is partly attributed to the development of new technologies and new materials, which promotes its application in many fields. Specifically for flexible transparent electrodes, currently commercially available conductive transparent indium tin oxide (ITO) films have inherent limitations when applied to flexible transparent electrodes, such as high production costs, high conductive surface roughness, poor material brittleness, and flexibility Shortcomings such as poor sex. Based on these problems, several alternative conductive materials such as carbon nanotubes, graphene, conductive polymers, metal grids, and metal nanowires have been studied by researchers in order to prepare flexible transparent electrodes with low cost, good mechanical properties and good flexibility. Attention. Among them, carbon-based and polymer-based materials have limited photoelectric performance due to their inherent low conductivity; metal grids have good electrical conductivity, but there is a Murray interference effect, although the Murray effect can be eliminated by reducing the line width of the metal grid, such as It is realized by adopting the yellow light process technology, and the corresponding preparation cost is also greatly increased. Compared with the previous materials, the conductive network of metal nanowires has advantages in terms of photoelectric performance and clarity. Its nano-scale conductive network width completely eliminates the Murray interference effect, so it has the best application prospects.

However, in the process of preparing metal nanowires, there are still some process problems that need to be resolved. For example, in order to obtain high-quality, complete metal nanowires with excellent photoelectric properties, it often takes a lot of manpower and money to post-process and purify the prepared metal nanowires, which is not conducive to controlling production costs. The performance of transparent electrodes based on metal nanowires depends on three processes: (1) the aspect ratio of the synthesized metal nanowires and the monodispersity of the size; (2) the purity of the nanowire purification, and the post-processing to remove the nano-shorts Rods, particles and polymers as surfactants; (3) The uniformity of the conductive network when the nanowires are coated and formed into a film. Regarding the first process, the polyol method is most commonly used at present (using PVP as a capping agent and high-boiling ethylene glycol as a solvent and reducing agent) to obtain metal nanowires with suitable size and aspect ratio. According to the percolation theory, metal nanowires with a higher aspect ratio have better mechanical and optoelectronic properties. Therefore, based on this theory, a lot of research work is devoted to improving the synthesis method to prepare metal nanowires with ultra-long-diameter ratio. However, the currently reported methods for preparing metal nanowires with ultra-length-to-diameter ratios have inherent shortcomings, such as complex processes and cumbersome steps, which are not conducive to large-scale and reproducible preparation in actual production. In addition, improving the photoelectric performance of the transparent electrode by increasing the aspect ratio also has side effects. For example, the diameter of the metal nanowire reduces the actual conductive coverage area in the transparent electrode, which is detrimental to charge collection in optoelectronic devices. Another method is to improve the photoelectric performance of metal nanowires from the source without changing the aspect ratio of the metal nanowires. Impurities such as non-conductive polymer PVP, metal nanoparticles, nano short rods and so on that wrap the metal nanowires are removed by purification. Conventional centrifugal washing is the most commonly used method. However, this method is inefficient and takes a long time. Excessive centrifugation can also cause metal nanowires to agglomerate. New methods including filter cloth filtration, positive pressure filtration, and decantation have been reported. Although these new methods have improved purification efficiency, the post-processing steps are still broken down into small-scale, multi-step, and time-consuming processes. In addition, cross-flow filtration can realize the separation of metal nanowires and metal nanoparticles of the same size, but the yield of this method is low. Therefore, in order to further improve the quality of metal nanowires and reduce production costs for commercial applications, it is necessary to develop an industrially scalable, high-performance, and cost-controllable method for large-scale purification of metal nanowires. .

Summary of the invention

In view of the above-mentioned technical problems in the prior art, the present invention provides a device for macro-purifying metal-based nanowires. The dynamic stirring centrifugal filtration device includes:

The dynamic stirring centrifugal filter device includes: a filter base, a solution injection system, a filter cylinder, and a filtrate outflow system;

The filter cylinder includes a filter frame, a stirring device, and a filter membrane; the filter membrane includes a first filter area, a second filter area, and a third filter area in the vertical direction. The first filter area, the second filter area The inward included angle between any two of the filter area and the third filter area is less than 180 degrees, and a plurality of filter holes are distributed on the first filter area, the second filter area and the third filter area.

The first filter area, the second filter area, and the third filter area are at an angle to each other, which will increase the filter area of the filter membrane and improve the filter efficiency. The direction toward the stirring paddle is an inward direction.

Preferably, the pore sizes of the filter holes on the first filter zone, the second filter zone and the third filter zone are different.

Preferably, the pore size of the first filtration region is 100 nm-1 μm, and/or the pore size of the second filtration region is 1 μm-5 μm, and/or the pore size of the third filtration region is 5 μm-20 μm.

The use of filter membranes with different pore sizes will increase the filtration efficiency and also extend the service life.

Preferably, the stirring device includes an electric motor and a stirring paddle connected to the electric motor.

Preferably, the filtering device includes a stirring paddle selected from one of a single-screw stirring paddle, a double-screw stirring paddle, a single-hole stirring paddle, and a porous stirring paddle.

The stirring device includes an electric motor and a stirring paddle connected with the electric motor.

The solution injection system injects the replacement solvent during the stirring and filtration to ensure that the concentration of the metal-based nanowires in the stirring centrifugal filter cylinder is relatively stable during the filtration process, and the filtrate flows out of the collection system to collect the filtered by-products.

A method for purifying metal-based nanowires using the above-mentioned macro-purifying metal-based nanowire device includes the following steps:

S1: Use diluent to dilute the mother liquid of metal-based nanowires and inject it into the filter tank through the solution injection system;

S2: Start the stirring at a fixed stirring speed; while stirring, the elution solvent continuously flows in through the solution injection system to compensate for the loss of the filtrate flowing away; the concentration of the metal nanowires in the stirring state is maintained relatively stable, and the solvent is replaced;

S3: Stir for 20-50min, stop adding the rinse solvent, and continue to stir the concentrated solution;

S4: When the concentration of the solution was concentrated to reach 1mg mL ^{^-1} -15mg mL ^-1, to collect the purified concentrate at the bottom of the filter cylinder.

Preferably, the metal-based nanowires are: gold, silver, copper, iron, aluminum, nickel, tin, and the foregoing metal oxides.

Preferably, the diluent is selected from one or more of ethanol, isopropanol, alcohol, distilled water, acetone, n-hexane, and ethyl acetate.

Preferably, the dilution concentration of the metal-based nanowire mother liquor in S1 is 0.2 mg/mL-1.2 mg/mL.

Preferably, the stirring speed is 300-1200 revolutions/min.

The beneficial effects of the utility model include at least:

1. Accurately control the filtration pressure based on stirring. The filtration pressure comes from the centrifugal force generated when the liquid is stirred, which can be controlled by the stirring speed;

2. It has a larger filter area, allowing more liquid to be filtered at the same time. The three filter membranes are fixed on the filter tank through the framework of the filter tank, which has a larger filter area compared with the traditional filter and improves the filtration efficiency;

3. The shear force generated by the stirring can clean the surface of the filter membrane, prevent nanowires from gathering and blocking the filter pores of the filter membrane, reducing subsequent filtration efficiency and continuous filtration capacity. In addition, the setting of filter membranes with different pore diameters is beneficial to extend the filter membrane The service life of the filter membrane is also realized repeatedly, and the cost is reduced;

4. The solvent can be replaced by a variety of target solvents after the metal nanowires are concentrated through the solution injection system;

5. The purification, concentration and solvent exchange of the nanowires can be realized in one step during stirring, which simplifies the post-treatment process. The device basically solves the core problems of cumbersome steps, complicated processes, and high costs faced by the current industrialized preparation and purification of metal nanowires.

Description of the drawings

Figure 1 is a schematic diagram of an apparatus for macro-purification of metal-based nanowires.

Detailed ways

The following describes the technical solutions in the embodiments of the present utility model clearly and completely with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. . Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

Example 1

This embodiment provides a method for macro-purifying metal-based nanowires, and the experimental device is shown in FIG. 1.

1. Pre-setting of mother liquor dilution treatment and stirring, filtering and centrifugal device.

Dilute the copper nanowire mother liquor with ethanol to a concentration of 0.5 mg/mL, install a filter membrane on the stirring filter bar, the first filter area has a filter pore size of 0.1 μm, the second filter area has a filter pore size of 1 μm, and the third filter area filters The hole size is 10 μm, the stirring speed is set at 500 revolutions per minute, the double screw stirring paddle is used, and the rinsing solvent is set to ethanol.

2. Stirring, filtering and concentrating.

Pour 300 ml of diluent into a stirred centrifugal filter tank equipped with a filter membrane, turn on the stirring, and the rinsing solvent will continue to flow in from the top of the filter device through the solution injection system to compensate for the loss of filtrate flowing away, so that the copper nanometer is in a stirred state. The concentration of the thread remains relatively stable and acts as a replacement for the solvent. After 30 minutes of stirring and filtering, stop adding the rinse solvent while continuing to stir to concentrate the solution to the required concentration (5 mg mL ^-1 ). The required concentration time is 40 minutes. Finally, the purified nanowire concentrate is collected at the bottom of the stirred centrifugal filter tank.

Example 2

Dilute the silver nanowire mother liquor with isopropanol to a concentration of 0.5 mg/mL, install a filter membrane on the stirring filter bar, the first filter area has a filter pore size of 0.2 μm, the second filter area has a filter pore size of 2 μm, and the third filter The size of the regional filter hole is 15 μm, the stirring speed is set at 800 rpm, a porous screw stirring paddle is used, and the rinsing solvent is set to isopropanol.

2. Stirring, filtering and concentrating.

Pour 300 ml of diluent into a stirred centrifugal filter tank equipped with a filter membrane, turn on the stirring, and the rinsing solvent will continue to flow in from the top of the filter device through the solution injection system to compensate for the loss of the filtrate flowing away, so that the silver nanometers are in a stirred state. The concentration of the thread remains relatively stable and acts as a replacement for the solvent. After 30 minutes of stirring and filtering, stop adding the rinse solvent while continuing to stir to concentrate the solution to the required concentration (8 mg mL ^-1 ). The required concentration time is 30 minutes. Finally, the purified nanowire concentrate is collected at the bottom of the stirred centrifugal filter tank.

Example 3

Dilute the gold nanowire mother liquor with distilled water to a concentration of 0.2mg/mL, and install a filter membrane on the stirring filter rod. The pore size is 20 μm, the stirring speed is set at 500 rpm, a single-hole stirring paddle is used, and the rinsing solvent is set to distilled water.

2. Stirring, filtering and concentrating.

Pour 300 ml of diluent into a stirred centrifugal filter tank equipped with a filter membrane, turn on the stirring, and the rinsing solvent will continuously flow in from the top of the filter device through the solution injection system to compensate for the loss of filtrate flowing away, so that the gold nanometers are in a stirred state. The concentration of the thread remains relatively stable and acts as a replacement for the solvent. After 10 minutes of stirring and filtering, stop adding the rinse solvent while continuing to stir to concentrate the solution to the required concentration (5 mg mL ^-1 ). The concentration time required is 25 minutes. Finally, the purified nanowire concentrate is collected at the bottom of the stirred centrifugal filter tank.

Comparative example 1

The process conditions and raw materials used in this comparative example are the same as those in Example 1, except that the filter membrane is installed on the stirring filter rod in a vertical direction.

序号Serial number	浓缩浓度Concentrated concentration	所需时间Time required
实施例1Example 1	5mg mL ^-1 5mg mL ^-1	40min40min
对比例1Comparative example 1	5mg mL ^-1 5mg mL ^-1	150min150min

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present utility model and not to limit it. Although the present utility model has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be in the form Various changes have been made to the above and details without departing from the scope defined by the claims of the present invention.

Claims

A device for macro-purifying metal-based nanowires, including a dynamic stirring centrifugal filter device, characterized in that the dynamic stirring centrifugal filter device includes: a solution injection system, a filter cylinder, and a filtrate outflow system;

The filter cylinder includes a filter frame, a stirring device, and a filter membrane; the filter membrane includes a first filter area, a second filter area, and a third filter area in the vertical direction. The first filter area, the second filter area The inward included angle between any two of the filter area and the third filter area is less than 180 degrees, and a plurality of filter holes are distributed on the first filter area, the second filter area, and the third filter area; The stirring device includes an electric motor and a stirring paddle connected with the electric motor.
The device for macro-purifying metal-based nanowires according to claim 1, wherein the pore sizes of the filter holes on the first filter zone, the second filter zone and the third filter zone are different .
The apparatus for macro-purification of metal-based nanowires according to claim 1, wherein the pore size of the first filter region is 100 nm-1 μm, and/or the pore size of the second filter region is 1 μm -5 μm, and/or, the pore size of the third filter region is 5 μm-20 μm.
The device for macro-purification of metal-based nanowires according to claim 1, wherein the filtering device comprises a stirring paddle, and the stirring paddle is selected from the group consisting of single-screw stirring paddles, double-screw stirring paddles, and single-hole stirring paddles. One of paddles and porous stirring paddles.
The device for macro-purification of metal-based nanowires according to claim 1, wherein the solution injection system injects a replacement solvent during the stirring and filtration to ensure that the metal-based nanowires in the centrifugal filter tank are stirred during the filtration process. The concentration is relatively stable, and the filtrate flows out of the collection system to collect the filtered by-products.