Preparation method of high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock assistance
Through laser shock-assisted methods, the flattened one-dimensional nanowire network solves the problems of stress concentration and damage caused by scattered nanowires, and improves the quality and performance of the flexible conductive film.
Patent Information
- Application Number
- CN202510242457.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-06-24
AI Technical Summary
In the prior art, when one-dimensional nanowires are combined with two-dimensional materials in a scattered state, it is easy to cause stress concentration and damage of the two-dimensional material, and conventional solutions such as chemical modification, template method, and hot pressing method have problems such as environmental pollution, low production efficiency, and high energy consumption.
The laser shock-assisted method is used to flatten the scattered stacked nanowire network to reduce stress concentration when composited with two-dimensional materials, and impact and heat the nanowires through pulsed laser beams to form a high-quality two-dimensional nanowire network.
It effectively reduces the damage of two-dimensional materials during the composite process, and improves the quality and performance of flexible conductive films, including anti-oxidation, corrosion and fatigue resistance.
Smart Images
Figure CN120199549A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of transparent conductive films, and particularly to a preparation method of a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film assisted by laser shock. Background Art
[0002] The rapid development of technology has promoted the increasing demand for flexible electronic devices in fields such as flexible screens, solar cells, smart wearable devices, and sensors. To meet the demand for high-performance conductive materials in these fields, the development of flexible transparent conductive films with more excellent optoelectronic properties and stronger anti-fatigue properties remains an unremitting pursuit of people.
[0003] Currently, one-dimensional nanowire materials have occupied a certain market share in the application of flexible conductive films due to their advantages such as a high aspect ratio, good conductivity, and flexibility. However, the nanowire materials with a high specific surface area are easily oxidized and eroded during contact with air or corrosive liquids, resulting in a decline in device performance. With the popularization of the application of two-dimensional materials, it has been found that two-dimensional materials with an atomic-scale thickness planar structure have excellent optical transparency and stability, and also have good conductive properties, and can be used as an ideal protective material for the nanowire layer. By combining one-dimensional nanowires with two-dimensional materials, the advantages of both can be fully combined, so that the film has high-efficiency and stable conductive properties and stronger mechanical strength while maintaining ultrathin and high transparency. However, in the specific preparation process, one-dimensional nanowires will form a quasi-three-dimensional structure in a scattered stacking state, with a relatively high roughness. Directly combining them with two-dimensional materials will cause a large stress concentration in the two-dimensional materials due to irregular stacking, resulting in damage. To solve this problem, the conventional solutions of researchers and industry personnel are to improve the uniformity of the basic nanowire network through chemical, template, hot pressing, etc., or to add an intermediate layer and increase the thickness of the two-dimensional material. However, the limitations of these methods still restrict their market popularization and application. For example, during the surface modification process using chemical methods, the volatile organic compounds used usually cause environmental pollution; although the template method can prepare highly ordered structures, it usually has a low production efficiency; the hot pressing method has deficiencies such as high energy consumption, poor quality, and material limitations (for example, the glass transition temperature of PET material is lower than 120 °C. If the hot pressing temperature is too high, PET loses its original mechanical properties and transparency), etc.; the method of adding an intermediate layer and increasing the thickness of the two-dimensional material will inevitably cause a decrease in the optical transmittance of the film.
[0004] Based on this, the present invention provides a more reliable high-performance conductive material solution to meet the strict requirements of flexible electronic devices for conductive materials. Summary of the Invention
[0005] Aiming at the deficiencies of the above-mentioned existing technologies, the present invention provides a preparation method of a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock assistance. By means of laser shock assistance, the randomly stacked nanowire network is flattened to reduce the stress concentration problem during the composite process with two-dimensional materials, thereby improving the quality of the one-dimensional nanowire / two-dimensional material composite flexible conductive film.
[0006] To achieve the above object, the specific technical solution of the present invention is as follows:
[0007] The present invention provides a preparation method of a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock assistance, including the following steps:
[0008] S1. Prepare a nanowire layer on a substrate;
[0009] S2. Place the substrate with the nanowire layer on a bottom constraint layer, and sequentially lay a momentum transfer layer, a sacrificial layer, and a top constraint layer above the nanowire layer;
[0010] S3. Heat the nanowires, and at the same time perform shock operations on the nanowires with pulsed lasers; according to the nanowire material and the required degree of flattening, select an appropriate shock pressure, and cooperate with an appropriate heating laser power and incident angle to transform the nanowire network from the original three-dimensional form into a high-quality two-dimensional nanowire network with a certain flattened form;
[0011] S4. Composite a two-dimensional material layer above the nanowire layer after the laser shock operation to obtain a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film.
[0012] In order to reduce the breakage of two-dimensional materials caused by stress concentration during the composite process, the present invention performs high-quality flattening treatment on the nodes and main regions of nanowires in a laser shock-assisted manner to prepare a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film. Among them, the pulsed laser beam irradiates the sacrificial layer to generate an instantaneous plasma explosion shock wave. The shock wave is confined by the top confinement layer and propagates downward. The pressure is applied to the nanowires through the momentum transfer layer to flatten and lower-dimensionalize the randomly stacked nanowire network, so as to reduce the problem of stress concentration in the subsequent composite process, thereby greatly improving the quality of the composite flexible conductive film. The present invention effectively realizes the flattening of the main region of the nanowires by means of increasing the number of laser shocks or adjusting the shock energy, etc. (taking silver nanowires as an example, when a single shock is applied with a pulsed energy of 120 mj, significant deformation only occurs in the node region, while after 5 shocks, significant deformation occurs in the main region of the nanowires; and a single shock with a pulsed energy of 1000 mj can also cause significant deformation in the main region). At the same time, during the laser shock operation, serious lattice defects may be introduced into the nanowires. In order to avoid the damage to the nanowires caused by the strong pulsed laser and multiple shocks, the present invention controls the hot spot position and temperature by reasonably adjusting the heating laser energy and angle, realizes the high-quality two-dimensionalization of the nanowire network, and further effectively reduces the stress damage area of the subsequent composite two-dimensional material.
[0013] Further, in step S1, the method for preparing the nanowire layer includes, but is not limited to, spin coating or filtration.
[0014] Further, in step S1, the nanowires include, but are not limited to, one or more of metal nanowires, semiconductor nanowires, and oxide nanowires.
[0015] Still further, the metal nanowires include, but are not limited to, gold nanowires and silver nanowires; the semiconductor nanowires include, but are not limited to, silicon nanowires and zinc oxide nanowires; the oxide nanowires include, but are not limited to, titanium dioxide nanowires and iron oxide nanowires.
[0016] Further, in step S2, the bottom confinement layer is a material that can transmit the heating laser, including, but is not limited to, glass or polymer; the momentum transfer layer includes, but is not limited to, aluminum foil or tin foil; the sacrificial layer is a material with high absorption of pulsed laser, including, but is not limited to, graphite; the top confinement layer is a material that can transmit the shock laser, including, but is not limited to, glass or polymer.
[0017] Further, in step S3, the pulsed laser includes femtosecond pulsed laser, picosecond pulsed laser, nanosecond pulsed laser, or microsecond pulsed laser.
[0018] Further, in step S3, the heating method includes, but is not limited to, synchronous split-pulse laser heating, individual pulse laser heating, continuous laser heating, or hot stage heating.
[0019] Furthermore, when using the split synchronous pulse laser for heating, the operation of step S3 is as follows: Through at least one optical path management component such as a frequency doubling crystal, dichroic mirror, or semi-reflective mirror, a beam of pulsed laser emitted by a pulsed laser is split into two beams (the wavelengths of the two beams are the same or different), which are respectively used for laser shock and laser heating operations; The impact laser is controlled by a mirror group to apply an impact pressure to the processing area, and the heating laser is controlled to apply a plasmonic thermal effect to the processing area. The action areas of the two lasers are the same area; The energies of the impact laser and the heating laser are respectively regulated by variable attenuators; The spot size is adjusted by a focusing mirror; The optical path delay time is finely adjusted by the optical path distance.
[0020] When using the individual pulse laser for heating, the operation of step S3 is as follows: The individual pulse laser heating and the laser shock are respectively generated by two lasers, and the action areas of the two lasers are the same area;
[0021] When using continuous laser for heating, the operation of step S3 is as follows: The continuous laser heating and the laser shock are respectively generated by two lasers, and the action areas of the two lasers are the same area;
[0022] When using the hot stage heating method for heating, the operation of step S3 is as follows: Heating operations are carried out through a hot stage, and at the same time, a beam of pulsed laser emitted by a pulsed laser is used for laser shock operations.
[0023] Specifically, when using the split synchronous pulse laser for heating, the operation of step S3 is as follows: The synchronous split laser generated by the same pulsed laser is respectively used for shock and heating. The laser beam is frequency doubled through a nonlinear crystal, and part of the 1064 nm laser is converted into 532 nm laser; The 1064 nm laser and the 532 nm laser are divided into two independent beams through a dichroic mirror and are respectively used for shock and heating; The impact laser is controlled by a mirror group to apply an impact pressure to the processing area, and the heating laser is controlled to apply a plasmonic thermal effect to the processing area. The action areas of the two lasers are the same area; The energies of the 1064 nm laser and the 532 nm laser are respectively regulated by variable attenuators; The spot size is adjusted by a focusing mirror; The optical path delay time is finely adjusted by the optical path distance.
[0024] Further, in step S4, the method of compounding the two-dimensional material layer includes, but is not limited to, transfer, spin coating, or printing.
[0025] Further, in step S4, the two-dimensional material includes, but is not limited to, one or more planar structure materials with atomic-level thicknesses such as graphene, graphene oxide, transition metal dichalcogenides, hexagonal boron nitride, MXene, metal-organic framework materials, and two-dimensional perovskites.
[0026] Further, the structure of the high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film includes: an A / B bilayer structure, or an A / B / A sandwich structure, or an A / B / A / B alternating multi-layer composite form, and so on.
[0027] The present invention also provides a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film prepared by the method.
[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0029] The present invention uses a laser shock-assisted method to flatten the scattered and stacked nanowire network. The pulsed laser processing method has a short action time and flexible and controllable impact force, which is convenient for coupling with various thermal processing techniques such as photo-thermal processing and hot stage processing. After the pulsed laser shock-assisted processing, the surface of the nanowire network is flat and has a low roughness, which can reduce the cracking phenomenon of the two-dimensional material thin layer during the composite process, ensure the integrity of the flexible conductive film, further improve the antioxidant, anti-corrosion, anti-fatigue and other properties of the flexible conductive film, and effectively solve the problem of damage to the two-dimensional material caused by the irregular stacking of nanowires. Description of the Drawings
[0030] Figure 1 is a schematic diagram of the preparation method of the high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock assistance of the present invention;
[0031] Figure 2 is the SEM morphology of the composite flexible conductive films prepared in Example 1 and Comparative Example 1. Detailed Embodiments
[0032] The technical solutions of the present invention will be described clearly and completely below. 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 without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.
[0033] Example 1
[0034] A high-quality silver nanowire / graphene oxide composite flexible conductive film based on laser shock assistance, the preparation method includes the following steps:
[0035] (1) Clean the PET flexible substrate successively with acetone, alcohol, and deionized water, and then treat the surface of the PET flexible substrate with ozone for 30 min.
[0036] (2) Dilute the silver nanowire solution to 1 mg / mL with an isopropanol solution, disperse it evenly by micro-ultrasonic, disperse it on the surface of the treated PET flexible substrate by spin coating, and dry it at 80 °C for 30 min.
[0037] (3) Place the PET flexible substrate coated with a silver nanowire layer on the bottom constraint layer (glass), and successively lay a momentum transfer layer (aluminum foil), a sacrificial layer (graphite), and a top constraint layer (glass) above the nanowire layer.
[0038] (4) Process the nanowires by means of laser shock-assisted synchronous split-beam pulsed laser heating to prepare a highly flattened nanowire conductive network.
[0039] By means of laser beam splitting, a pulsed laser beam generated by the same laser is divided into an impact pulsed laser and a heating pulsed laser and acts on the same processing area. The specific optical path adjustment method is as follows: the laser beam is frequency-doubled through a nonlinear crystal, and part of the 1064 nm laser is converted into 532 nm laser; the 1064 nm laser and the 532 nm laser are divided into two independent beams through a dichroic mirror; the path of the impact laser is controlled by a mirror group so that it passes through the top glass constraint layer and irradiates the graphite sacrificial layer to generate a plasma explosion shock wave. The shock wave passes through the momentum transfer layer to provide mechanical pressure to the nanowires in the processing area. The path of the heating laser is controlled by a mirror group so that it passes through the bottom glass constraint layer and the PET substrate and directly irradiates the nanowires. The nanowire areas processed by the impact laser and the heating laser are the same area.
[0040] The total energy of the pulsed laser is controlled by the laser. At the same time, the pulsed energies of the impact laser and the heating laser are respectively regulated by variable attenuation mirrors. The spot size is adjusted by a focusing mirror so that the spot diameter is 2 - 3 mm.
[0041] Turn on the laser and perform single-point processing operations of laser-assisted synchronous split-beam pulsed laser heating. Control the synchronous movement of the processed sample, the constraint layer, the momentum transfer layer, and the sacrificial layer through a moving platform to achieve surface processing operations. Control the spot overlap rate by the moving speed of the moving platform.
[0042] The original wavelength of the laser used in this embodiment is 1064 nm, and the pulse width is 1.4 us. Through second harmonic generation in a nonlinear crystal, a dichroic mirror is used to divide the frequency-doubled laser into two single-wavelength lasers of 1064 nm and 532 nm, which are used for laser shock and laser heating respectively. Through a variable attenuation mirror, the shock laser energy is controlled to be 240 mj, and the heating laser energy is 200 mj. The operating frequency of the laser is 10 Hz, and the spot coincidence rate is controlled to be 25% through a moving platform to achieve surface processing.
[0043] (5)The graphene oxide solution diluted to 0.5 mg / mL was spin-coated on the surface of the nanowire layer after laser shock treatment at a rotation rate of 4000 rpm / min for 30 s to obtain a high-quality silver nanowire / graphene oxide composite flexible conductive film.
[0044] In this embodiment, a relatively large pulsed laser energy is used to flatten the nanowire junctions and the main regions. At the same time, by adjusting the heating pulse energy, the nanowires are at an appropriate temperature during the compression process to reduce the stress damage during the compression process, and finally a high-quality and highly flattened nanowire network is obtained. As Figure 2 can be seen from c, when the method of the present invention is used to process the nanowires, there is no obvious damage to the obtained composite flexible conductive film. If the pulsed laser energy is insufficient during the laser treatment process, the nanowires only have significant deformation caused by the impact pressure at the junctions, and there is no significant flattening effect in the main regions of the nanowires. There are still significant large-area damages caused by height differences in the obtained composite flexible conductive film (as Figure 2 shown in b).
[0045] Comparative Example 1
[0046] (1)The PET flexible substrate was sequentially cleaned with acetone, alcohol and deionized water, and then the surface of the PET flexible substrate was treated with ozone for 30 min.
[0047] (2)The purchased silver nanowire solution was diluted to 1 mg / mL with an isopropanol solution, dispersed evenly by micro-ultrasonic, and dispersed on the surface of the treated PET flexible substrate by spin-coating, and dried at 80 °C for 30 min.
[0048] (3)The graphene oxide solution diluted to 0.5 mg / mL was spin-coated on the surface of the nanowire layer after laser shock treatment at a rotation rate of 4000 rpm / min for 30 s to obtain a high-quality silver nanowire / graphene oxide composite flexible conductive film.
[0049] From Figure 2It can be seen that without treating the nanowires and directly compounding them with the two-dimensional material, significant damage to the two-dimensional material occurs in the obtained composite flexible conductive film, which seriously damages the comprehensive performance and service life of the composite film layer.
[0050] The above specific embodiments have described the implementation of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple variations all belong to the protection scope of the present invention.
Claims
1. A method for preparing high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock, characterized in that: The following steps are involved: S1, preparing a nanowire layer on a substrate; S2, placing the substrate covered with the nanowire layer on the bottom constraint layer, and laying a momentum transfer layer, a sacrificial layer and a top constraint layer in sequence on the nanowire layer; S3. heating the nanowires and simultaneously impacting the nanowires with a pulsed laser; S4. Composite a two-dimensional material layer on top of the nanowire layer after laser shock operation to obtain a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film.
2. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: In step S3, the pulse laser includes femtosecond pulse laser, picosecond pulse laser, nanosecond pulse laser or microsecond pulse laser.
3. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: In step S3, the heating method includes but is not limited to synchronous split-beam pulse laser heating, single pulse laser heating, continuous laser heating or hot stage heating.
4. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 3, characterized in that: When the split-beam synchronous pulse laser is used for heating, the operation of step S3 is as follows: a pulse laser beam emitted by a pulse laser is divided into two beams through at least one optical path management element selected from frequency doubling crystals, dichroic mirrors or half-reflecting mirrors, which are used for laser shock and laser heating operations respectively; the shock laser is controlled to apply shock pressure to the processing area through a reflector group, and the heating laser is controlled to apply plasmon thermal effect to the processing area, and the action areas of the two laser beams are the same area; the shock laser and heating laser energies are respectively regulated by a variable attenuation mirror; the spot size is adjusted by a focusing mirror; and the optical path delay time is fine-tuned by the optical path distance.
5. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: The nanowires include, but are not limited to, one or more of metal nanowires, semiconductor nanowires, and oxide nanowires.
6. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: The two-dimensional material is a planar structure material with atomic-level thickness, including but not limited to one or more of graphene, graphene oxide, transition metal dichalcogenides, hexagonal boron nitride, MXene, metal-organic framework materials, and two-dimensional perovskite.
7. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: The bottom constraining layer is a material that is transparent to the heating laser, including but not limited to glass or polymer; the momentum transfer layer includes but is not limited to aluminum foil or tin foil; the sacrificial layer is a material that has high absorption to the pulsed laser, including but not limited to graphite; the top constraining layer is a material that is transparent to the shock laser, including but not limited to glass or polymer.
8. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: Methods of compounding the two-dimensional material layer include but are not limited to transfer, spin coating or printing.
9. The method for preparing a high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film based on laser shock-assisted method according to claim 1, characterized in that: The structure of the high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film includes: an A / B type double-layer structure, or an A / B / A type sandwich structure, or an A / B / A / B type alternating multilayer composite form, and so on.
10. A high-quality one-dimensional nanowire / two-dimensional material composite flexible conductive film prepared by the method according to any one of claims 1 to 9.