Double-sided transparent conductive film and preparation method of double-sided transparent conductive film

Abstract

The invention discloses a double-sided transparent conductive film and a preparation method of the double-sided transparent conductive film, in the double-sided transparent conductive film, a first patterned adhesive layer is arranged on a first surface, a second patterned adhesive layer is arranged on a second surface, and the first surface and the second surface are oppositely arranged. A plurality of first grooves are formed in the first patterned adhesive layer, the plurality of first grooves are communicated, first conductive laminated structures are arranged in the first grooves, and the plurality of first conductive laminated structures are connected to form a first grid structure. A plurality of second grooves are formed in the second patterned adhesive layer, and the plurality of second conductive laminated structures are connected to form a second grid structure. The vertical projection of the first grid structure and the vertical projection of the second grid structure coincide in the thickness direction of the transparent substrate. Thus, the performance of the transparent conductive film can be improved by arranging the double-sided grid structures, the first grid structures and the second grid structures are accurately aligned, the metal duty ratio is greatly reduced, and therefore high light transmittance is achieved while high conductivity is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive layers, and particularly relates to a double-sided transparent conductive film and a preparation method thereof. Background Art

[0002] Due to their high light transmittance and high conductivity, transparent conductive functional materials have been widely used in optoelectronic devices, such as electrochromic devices, optical window electromagnetic shielding, flat panel displays, photovoltaic devices, and touchscreens. Currently, widely used transparent conductive functional materials include ITO, metal nanowires, carbon materials, and metal grids. However, with the development and progress of modern technology, the requirements for optoelectronic devices have gradually increased. For example, for electrochromic devices, large size, flexibility, fast color change speed, and high color contrast are required; for the field of transparent electromagnetic shielding, large size, strong electromagnetic shielding in a wide frequency band, and high light transmittance are required. In the applications of these high-performance optoelectronic devices, high-conductivity and high-transparency transparent conductive functional materials play a crucial role. Therefore, metal grids have important advantages due to their independently adjustable properties of high conductivity and high light transmittance.

[0003] Currently, the metal grid transparent conductive functional materials are usually single-layer grids, with insufficient conductivity, and it is impossible to achieve high shielding efficiency in a wide frequency band in the field of electromagnetic shielding. When applied to a double-layer electrochromic device with a fast color change speed and thinness, it is required to fabricate devices on both the front and back sides of the double-layer conductive grid. However, only one side of the single-layer grid is exposed on the surface, so it is impossible to fabricate double-layer devices. Summary of the Invention

[0004] The present invention provides a double-sided transparent conductive film. By setting the grid structures on both sides, the performance of the transparent conductive film can be improved, and the first grid structure and the second grid structure are accurately aligned, greatly reducing the metal duty ratio, thereby ensuring high conductivity while having a relatively high light transmittance.

[0005] In a first aspect, an embodiment of the present invention provides a double-sided transparent conductive film, including a transparent substrate, a first patterned adhesive layer, and a second patterned adhesive layer;

[0006] The transparent substrate includes a first surface and a second surface disposed opposite to each other. The first patterned adhesive layer is disposed on the first surface, and the second patterned adhesive layer is disposed on the second surface;

[0007] A plurality of first grooves are provided in the first patterned adhesive layer. The plurality of first grooves are connected and communicated, and a first conductive stack structure is provided in the first grooves. The plurality of first conductive stack structures are connected to form a first grid structure;

[0008] A plurality of second grooves are provided in the second patterned glue layer. The plurality of second grooves are communicated with each other, and a second conductive laminated structure is provided in the second grooves. The plurality of second conductive laminated structures are connected to form a second grid structure;

[0009] In the thickness direction of the transparent substrate, the vertical projection of the first grid structure coincides with the vertical projection of the second grid structure.

[0010] Optionally, both the first conductive laminated structure and the second conductive laminated structure include a conductive structure or a laminated structure of a conductive structure and a functional structure.

[0011] Optionally, the first conductive laminated structure includes a first conductive structure. The first conductive structure includes a first sub-structure and a second sub-structure arranged in a laminated manner. The first sub-structure is located on the side of the second sub-structure close to the transparent substrate, and the materials of the first sub-structure and the second sub-structure are different;

[0012] The second conductive laminated structure includes a second conductive structure. The second conductive structure includes a third sub-structure and a fourth sub-structure arranged in a laminated manner. The third sub-structure is located on the side of the fourth sub-structure close to the transparent substrate, and the materials of the third sub-structure and the fourth sub-structure are different.

[0013] Optionally, the materials of the first sub-structure and the third sub-structure are the same, and the materials of the second sub-structure and the fourth sub-structure are the same.

[0014] Optionally, the first conductive laminated structure includes a third conductive structure. The third conductive structure includes a fifth sub-structure and a sixth sub-structure arranged in a laminated manner. The fifth sub-structure is located on the side of the sixth sub-structure close to the transparent substrate, and the materials of the fifth sub-structure and the sixth sub-structure are different;

[0015] The second conductive laminated structure includes a laminated structure of a fourth conductive structure and a first functional structure. The fourth conductive structure includes a seventh sub-structure and an eighth sub-structure. The seventh sub-structure is located on the side of the eighth sub-structure close to the transparent substrate, and the eighth sub-structure is located between the first functional structure and the seventh sub-structure.

[0016] Optionally, in the thickness direction of the transparent substrate, the depth of the first groove is less than the depth of the second groove.

[0017] Optionally, both the first conductive laminated structure and the second conductive laminated structure include a laminated structure of a fifth conductive structure and a second functional structure;

[0018] The fifth conductive structure includes a ninth sub-structure and a tenth sub-structure. The ninth sub-structure is located on the side of the tenth sub-structure close to the transparent substrate, and the tenth sub-structure is located between the ninth sub-structure and the second functional layer.

[0019] Optionally, the material of the conductive structure includes one of metal nanoparticles, metal nanowires, or bulk metal materials;

[0020] The functional material includes an ion storage material.

[0021] Optionally, denoting the depth of the first groove as D1 and the width of the first groove as D2, the depth and width of the first groove satisfy 4≥D1 / D2≥1;

[0022] Denoting the depth of the second groove as D3 and the width of the second groove as D4, the depth and width of the second groove satisfy 4≥D3 / D4≥1.

[0023] In a second aspect, an embodiment of the present invention further provides a method for preparing a double-sided transparent conductive film for preparing the double-sided transparent conductive film according to any item of the first aspect. The preparation method includes:

[0024] Providing a transparent substrate;

[0025] Preparing a first patterned glue layer on the first surface of the transparent substrate and a second patterned glue layer on the second surface of the transparent substrate, wherein the first surface and the second surface are oppositely arranged;

[0026] Forming a plurality of first grooves connected in communication in the first patterned glue layer, and filling a first conductive stacked structure in the first grooves so that a plurality of the first conductive stacked structures are connected to form a first grid structure;

[0027] According to the plurality of first grooves in the first patterned glue layer, a plurality of second grooves in alignment are formed in the second patterned glue layer by means of alignment imprinting or self-masking lithography, so that along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide. Wherein, a second conductive stacked structure is filled in the second grooves so that a plurality of the second conductive stacked structures are connected to form the second grid structure.

[0028] In an embodiment of the present invention, the transparent substrate includes a first surface and a second surface that are oppositely disposed. The first patterned glue layer disposed on the first surface includes a plurality of first grooves, the plurality of first grooves are communicatively arranged, and a first conductive stack structure is disposed in the first grooves. The plurality of first conductive stack structures are connected to form a first grid structure. The second patterned glue layer disposed on the second surface includes a plurality of second grooves, the plurality of second grooves are communicatively arranged, and a second conductive stack structure is disposed in the second grooves. The plurality of second conductive stack structures are connected to form a second grid structure. Along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide. Thus, on the one hand, since both the first surface and the second surface of the transparent substrate include conductive grid structures, the conductivity of the double-sided transparent conductive film is improved. On the other hand, since along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide, that is, the first grid structure and the second grid structure are in high-precision alignment, the metal duty cycle is greatly reduced, thereby improving the light transmittance of the double-sided transparent conductive film on the basis of ensuring high conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a top view structural schematic diagram of a double-sided transparent conductive film provided by an embodiment of the present invention;

[0030] Figure 2 is a cross-sectional structural schematic diagram of a double-sided transparent conductive film provided by an embodiment of the present invention;

[0031] Figure 3 is a cross-sectional schematic diagram of another double-sided transparent conductive film provided by an embodiment of the present invention;

[0032] Figure 4 is a cross-sectional schematic diagram of yet another double-sided transparent conductive film provided by an embodiment of the present invention;

[0033] Figure 5 is a cross-sectional schematic diagram of yet another double-sided transparent conductive film provided by an embodiment of the present invention;

[0034] Figure 6 is a flowchart schematic diagram of a preparation method of a double-sided transparent conductive film provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings rather than all structures.

[0036] The inventors have found through research that in the prior art, the metal grid transparent conductive functional material is usually a single-layer grid, that is, a grid structure is formed on one side surface of a transparent substrate. However, for fields such as electromagnetic shielding and electrochromism, in order to improve the conductive performance of its devices, a double-layer conductive grid structure is often required. Currently, the transparent conductive functional material with a double-layer conductive grid structure is usually prepared by forming a second grid structure on the surface of the grid structure of the single-layer grid. The double-layer grid obtained by this method has a low light transmittance of the transparent conductive material because the grid structures are not accurately aligned, resulting in a metal duty cycle that is twice that of the single-layer grid. In addition, when applied to a double-layer electrochromic device with a fast color change speed and thinness, it is required to fabricate devices on both the front and back sides of the double-layer grid structure. However, only one side of the grid structure is exposed on the surface in the above method, so the fabrication of the double-layer device cannot be achieved.

[0037] Figure 1 FIG. 4 is a top view structural schematic diagram of a double-sided transparent conductive film provided by an embodiment of the present invention. Figure 2 FIG. 5 is a cross-sectional structural schematic diagram of a double-sided transparent conductive film provided by an embodiment of the present invention. Refer to Figure 1 and Figure 2 FIG. 5, the double-sided transparent conductive film includes a transparent substrate 10, a first patterned adhesive layer 20, and a second patterned adhesive layer 30. The transparent substrate 10 includes a first surface S1 and a second surface S2 that are oppositely arranged. The first patterned adhesive layer 20 is disposed on the first surface S1, and the second patterned adhesive layer 30 is disposed on the second surface S2. A plurality of first grooves 210 are formed in the first patterned adhesive layer 20. The plurality of first grooves 210 are connected and communicated, and a first conductive stacked structure 40 is disposed in the first grooves 210. The plurality of first conductive stacked structures 40 are connected to form a first grid structure 400. A plurality of second grooves 310 are formed in the second patterned adhesive layer 30. The plurality of second grooves 310 are connected and communicated, and a second conductive stacked structure 50 is disposed in the second grooves 310. The plurality of second conductive stacked structures 50 are connected to form a second grid structure 500. Along the thickness direction of the transparent substrate 10, the vertical projection of the first grid structure 400 and the vertical projection of the second grid structure 500 coincide.

[0038] Specifically, refer to Figure 1 and Figure 2, the transparent substrate 10 includes a first surface S1 and a second surface S2 which are oppositely arranged. Among them, the first surface S1 can be the front surface of the transparent substrate 10, and the second surface S2 can be the back surface of the transparent substrate 10. Patterned glue layers are provided on both the first surface S1 and the second surface S2 of the transparent substrate 10. Exemplarily, the patterned glue layer on the first surface S1 is the first patterned glue layer 20, and the patterned glue layer on the second surface S2 is the second patterned glue layer 30. It can be understood that the patterned glue layer can be a photoresist layer or an imprint glue layer, and the present invention does not limit this. Those skilled in the art can set it according to needs. First, the first patterned glue layer 20 can be patterned by imprinting or lithography to form a plurality of first grooves 210 in the first patterned glue layer 20. The plurality of first grooves 210 communicate with each other and form a grid-like trench structure as a whole. For example, in the embodiment shown in Figure 1 , the grid-like trench structure is a plurality of continuous regular hexagon structures. Then, a variety of different conductive or functional materials are filled in the plurality of first grooves 210 to form a first conductive stack structure 40 in the first grooves 210. Since the plurality of first grooves 210 communicate with each other and form a grid-like trench structure as a whole, the plurality of first conductive stack structures 40 are electrically connected to each other to form a first grid structure 400. It can be understood that the first grid structure 400 is essentially a conductive wire. Therefore, the first grid structure 400 itself is opaque, and the position where the meshes of the first grid structure 400 are located is a light-transmitting area.

[0039] After the first groove 210 and the first grid structure 400 are fabricated, multiple second grooves 310 in alignment are formed on the second patterned photoresist layer 30 of the second surface S2 by means of high-precision alignment imprinting or self-masking lithography with the multiple first grooves 210 in the first patterned photoresist layer 20 as templates. That is, along the thickness direction of the transparent substrate 10, the first groove 210 and the second groove 310 completely overlap. Then, various different conductive or functional materials are filled into the second grooves 310 to form a second conductive stack structure 50 in the second grooves 310. Since the multiple second grooves 310 are connected and form a grid-like trench structure as a whole, multiple second conductive stack structures 50 are electrically connected to each other to form a second grid structure 500. Since the first groove 210 and the second groove 310 completely overlap, along the thickness direction of the transparent substrate 10, the vertical projection of the first grid structure 400 and the vertical projection of the second grid structure 500 overlap. In this way, on the one hand, since both the first surface S1 and the second surface S2 of the transparent substrate 10 include conductive grid structures, the conductivity of the double-sided transparent conductive film is improved. On the other hand, since along the thickness direction of the transparent substrate 10, the vertical projection of the first grid structure 400 and the vertical projection of the second grid structure 500 overlap, that is, the first grid structure 400 and the second grid structure 500 are fabricated with high-precision alignment, the light-transmitting regions and the grid structures between them overlap, greatly reducing the metal duty cycle of the two, thereby improving the light transmittance of the double-sided transparent conductive film on the basis of ensuring high conductivity.

[0040] It should be noted that Figure 1 only the grid-like trench structure in the form of multiple consecutive regular hexagon structures is taken as an example for illustration, but it is not limited thereto. In other embodiments, the grid-like trench structure can also be a square, etc., which can be set by those skilled in the art according to needs.

[0041] In summary, in the embodiment of the present invention, the transparent substrate includes a first surface and a second surface arranged opposite to each other. The first patterned glue layer disposed on the first surface includes a plurality of first grooves, the plurality of first grooves are connected and arranged, and a first conductive stack structure is disposed in the first grooves, and the plurality of first conductive stack structures are connected to form a first grid structure. The second patterned glue layer disposed on the second surface includes a plurality of second grooves, the plurality of second grooves are connected and arranged, and a second conductive stack structure is disposed in the second grooves, and the plurality of second conductive stack structures are connected to form a second grid structure. Along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide. Thus, on the one hand, since both the first surface and the second surface of the transparent substrate include conductive grid structures, the conductivity of the double-sided transparent conductive film is improved. On the other hand, since along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide, that is, the first grid structure and the second grid structure are in high-precision alignment, and the metal duty cycle is greatly reduced, so that on the basis of ensuring high conductivity, the light transmittance of the double-sided transparent conductive film is improved.

[0042] Optionally, on the basis of the above embodiment, continue to refer to Figure 2 , both the first conductive stack structure 40 and the second conductive stack structure 50 include a conductive structure or a stacked structure of a conductive structure and a functional structure. Specifically, the first conductive stack structure 40 may only include a conductive structure to ensure the high conductivity of the first grid structure 400, or may include a stacked structure of a conductive structure and a functional structure to realize the multifunctionality of the first grid structure 400. Similarly, the second conductive stack structure 50 may only include a conductive structure to ensure the high conductivity of the second grid structure 500, or may include a stacked structure of a conductive structure and a functional structure to realize the multifunctionality of the second grid structure 400. It should be noted that when the first conductive stack structure 40 only includes a conductive structure, the second conductive stack structure 50 may only include a conductive structure or may include a stacked structure of a conductive structure and a functional structure. When the second conductive stack structure 50 only includes a conductive structure, the first conductive stack structure 50 may only include a conductive structure or may include a stacked structure of a conductive structure and a functional structure. The present invention does not limit this, and those skilled in the art can set it according to needs. It can be understood that in the same type of grooves, the types of filled materials are the same. For example, when only a conductive structure is disposed in the first groove 210, all the first grooves 210 only dispose a conductive structure, and the materials of the conductive structures in different first grooves 210 are the same.

[0043] It should be noted that the material of the conductive structure may include any one of metal nanoparticles, metal nanowires or bulk metal materials, and the material of the functional structure may include an ion storage material. Among them, the ion storage material may include at least one of MXene, polymers and inorganic materials. MXene is an ion storage material for two-dimensional materials. Polymers may include polythiophene or PEDOT:PSS, etc. Inorganic materials may include tungsten oxide or titanium dioxide, etc. The present invention does not limit the above specific materials, and those skilled in the art can set them as needed.

[0044] Optionally, in one embodiment, Figure 3 is a schematic cross-sectional view of another double-sided transparent conductive film provided by an embodiment of the present invention. Refer to Figure 3 , the first conductive stack structure 40 includes a first conductive structure 410. The first conductive structure 410 includes a first sub-structure 411 and a second sub-structure 412 arranged in a stack. The first sub-structure 411 is located on the side of the second sub-structure 412 closer to the transparent substrate 10, and the materials of the first sub-structure 411 and the second sub-structure 412 are different. The second conductive stack structure 50 includes a second conductive structure 510. The second conductive structure 510 includes a third sub-structure 513 and a fourth sub-structure 514 arranged in a stack. The third sub-structure 513 is located on the side of the fourth sub-structure 514 closer to the transparent substrate 10, and the materials of the third sub-structure 513 and the fourth sub-structure 514 are different.

[0045] Exemplarily, as in Figure 1 and Figure 3 In the shown embodiment, it can be set that both the first grid structure and the second grid structure are conductive structures, that is, the first conductive stack structure 40 includes a first conductive structure 410, and the first conductive structure 410 includes a first sub-structure 411 and a second sub-structure 412 arranged in a stack. Specifically, the material of the first sub-structure 411 may include silver nanoparticles (metal nanoparticles), and the material of the second sub-structure 412 may include copper. Further, after preparing a plurality of first grooves 210 on the first surface S1, if the depth of the first groove 210 is 6 μm, then 1 μm thick silver nanoparticles can be scrape-coated in the first groove 210 by a scraping method and annealed at 130 °C for 15 minutes to obtain the first sub-structure 411. Then, 5 μm thick copper is deposited on the surface of the first sub-structure 411 away from the transparent substrate 10 by electroplating to form the second sub-structure 412. At this time, the light transmittance (the first grid structure 400) of the double-sided transparent conductive film is 86%.

[0046] Next, taking the multiple first grooves 210 in the first patterned glue layer 20 as templates, through the method of high-precision alignment imprinting, a plurality of aligned second grooves 310 are formed on the second patterned glue layer 30 of the second surface S2. That is, along the thickness direction of the transparent substrate 10, the first groove 210 and the second groove 310 are completely coincident (it can be understood that theoretically, it is required to set the first groove 210 and the second groove 310 to be completely coincident, but due to the limitations of the manufacturing process, there will be a deviation between the first groove 210 and the second groove 310 in the thickness direction of the transparent substrate 10). The second conductive stack structure 50 includes a second conductive structure 510, and the second conductive structure 510 includes a stacked third sub-structure 513 and a fourth sub-structure 514. Among them, the material of the third sub-structure 513 may include silver nanoparticles (metal nanoparticles), and the material of the fourth sub-structure 514 may include copper. If the depth of the second groove 310 is the same as the depth of the first groove 210, then 1 μm thick silver nanoparticles can be scrape-coated in the second groove 310 by the scrape-coating method and annealed at 130 °C for 15 minutes to obtain the third sub-structure 513. Then, a 5 μm thick copper film is plated on the surface of the third sub-structure 513 away from the transparent substrate 10 by chemical plating to form the fourth sub-structure 514. At this time, the light transmittance of the double-sided transparent conductive film (the first grid structure 400 and the second grid structure 500) is 84%. Furthermore, when the present invention is applied to electromagnetic shielding, on the one hand, since both the first grid structure 400 and the second grid structure 500 have high conductivity, the electromagnetic shielding efficiency of the device can be improved. For example, in the frequency band of 300 MHz - 18 GHz, the shielding efficiency is greater than 40 dB. On the other hand, since along the thickness direction of the transparent substrate 10, the vertical projections of the first grid structure 400 and the second grid structure 500 coincide, that is, the first grid structure and the second grid structure are in high-precision alignment, the metal duty cycle is greatly reduced, so that on the basis of ensuring high conductivity, the light transmittance of the double-sided transparent conductive film is improved.

[0047] It should be noted that the above embodiments are only exemplarily described with the materials of the first sub-structure 411 and the third sub-structure 513 being the same, and the materials of the second sub-structure 412 and the fourth sub-structure 514 being the same, but are not limited thereto. In other embodiments, the materials of the first sub-structure 411 and the third sub-structure 513 may also be set to be different, and the materials of the second sub-structure 412 and the fourth sub-structure 514 may be different. Those skilled in the art can set according to needs.

[0048] In yet another embodiment, Figure 4 is a schematic cross-sectional view of another double-sided transparent conductive film provided by an embodiment of the present invention. Refer to Figure 4, the first conductive stack structure 40 includes a third conductive structure 430. The third conductive structure 430 includes a fifth sub-structure 435 and a sixth sub-structure 436 arranged in a stack. The fifth sub-structure 435 is located on the side of the sixth sub-structure 436 closer to the transparent substrate 10, and the materials of the fifth sub-structure 435 and the sixth sub-structure 436 are different. The second conductive stack structure 50 includes a stacked structure of a fourth conductive structure 540 and a first functional structure 520. The fourth conductive structure 540 includes a seventh sub-structure 547 and an eighth sub-structure 548. The seventh sub-structure 547 is located on the side of the eighth sub-structure 548 closer to the transparent substrate 10, and the eighth sub-structure 548 is located between the first functional structure 520 and the seventh sub-structure 547.

[0049] Specifically, as Figure 1 and Figure 4 shown in the embodiment, the first grid structure can be set as a conductive structure. That is, the first conductive stack structure 40 includes a third conductive structure 430, and the third conductive structure 430 includes a fifth sub-structure 435 and a sixth sub-structure 436 arranged in a stack. Specifically, the material of the fifth sub-structure 435 may include silver nanoparticles (metal nanoparticles), and the material of the sixth sub-structure 436 may include copper. Then, after preparing a plurality of first grooves 210 on the first surface S1, if the depth of the first groove 210 is 6 μm, 1 μm thick silver nanoparticles can be scrape-coated in the first groove 210 by a scrape-coating method and annealed at 130 °C for 15 minutes to obtain the fifth sub-structure 435. Then, a 5-μm-thick copper is deposited on the surface of the fifth sub-structure 435 away from the transparent substrate 10 by electro-deposition to form the sixth sub-structure 436. At this time, the light transmittance of the double-sided transparent conductive film (the first grid structure 400) is 86%.

[0050] Next, using the multiple first grooves 210 in the first patterned photoresist layer 20 as a template, a plurality of aligned second grooves 310 are formed on the second patterned photoresist layer 30 of the second surface S2 by means of self-masking lithography. That is, along the thickness direction of the transparent substrate 10, the first grooves 210 and the second grooves 310 are completely coincident. The second grid structure includes a stacked structure of a conductive structure and a functional structure. That is, the second conductive stacked structure 50 includes a stacked structure of a fourth conductive structure 540 and a first functional structure 520. The fourth conductive structure 540 includes a seventh sub-structure 547 and an eighth sub-structure 548 which are stacked. Among them, the material of the seventh sub-structure 547 may include silver nanoparticles (metal nanoparticles), the material of the eighth sub-structure 548 may include nickel, the depth of the second groove 310 may be 8 μm, then 1-μm-thick silver nanoparticles can be spin-coated in the second groove 310 by a spin-coating method and annealed at 130 °C for 15 minutes to obtain the seventh sub-structure 547. Then, 5-μm-thick nickel is deposited on the surface of the seventh sub-structure 547 away from the transparent substrate 10 by electrodeposition to form the eighth sub-structure 548. Then, MXene material is spin-coated on the side of the eighth sub-structure 548 away from the seventh sub-structure 547 to fill the second groove 310 to form the first functional structure 520. At this time, the light transmittance of the double-sided transparent conductive film (the first grid structure 400 and the second grid structure 500) is 84%. Since the first functional structure 520 has an ion-conducting function, the second grid structure formed by the fourth conductive structure 540 and the first functional structure 520 not only has high conductivity but also has an ion-conducting function. When it is applied to an electrochromic device, the second grid structure can be used as the counter electrode in the preparation of the electrochromic device. Moreover, the first grid structure and the second grid structure are in high-precision alignment, and the metal duty cycle is greatly reduced, thereby improving the light transmittance of the double-sided transparent conductive film and further improving the contrast of the electrochromic device.

[0051] It should be noted that by setting the depth of the second groove 310 to be greater than the depth of the first groove 210, a larger space is provided for the second groove 310 in the thickness direction of the transparent substrate 10, so that the conductive structure and the functional structure can be accommodated simultaneously, thereby ensuring that the second conductive stacked structure 40 has high conductivity and multifunctionality.

[0052] Optionally, in another embodiment, Figure 5 is a cross-sectional schematic diagram of another double-sided transparent conductive film provided by an embodiment of the present invention. Refer to Figure 5, both the first conductive stack structure 40 and the second conductive stack structure 50 include a stack structure of a fifth conductive structure 450 and a second functional structure 530. The fifth conductive structure 450 includes a ninth sub-structure 459 and a tenth sub-structure 4510. The ninth sub-structure 459 is located on the side of the tenth sub-structure 4510 close to the transparent substrate 10, and the tenth sub-structure 4510 is located between the ninth sub-structure 459 and the second functional layer 530.

[0053] Specifically, as Figure 1 and Figure 5 shown in the embodiment, it can be set that both the first grid structure and the second grid structure include a stack structure of a conductive structure and a functional structure. That is, both the first conductive stack structure 40 and the second conductive stack structure 50 include a stack structure of a fifth conductive structure 450 and a second functional structure 530. The fifth conductive structure 450 includes a ninth sub-structure 459 and a tenth sub-structure 4510 arranged in a stack. Furthermore, by means of double-sided precise alignment imprinting, a first groove 210 can be formed in the first patterned glue layer 20 and a second groove 310 can be formed in the second patterned glue layer 30 at the same time. That is, along the thickness direction of the transparent substrate 10, the first groove 210 and the second groove 310 are completely coincident.

[0054] Specifically, the material of the ninth sub-structure 459 may include silver nanoparticles (metal nanoparticles), the material of the tenth sub-structure 4510 may include copper, and the depth of the first groove 210 and the second groove 310 is 1 μm - 15 μm. Then, silver nanoparticles can be scrape-coated in the first groove 210 and dried at 120 °C for 30 min to obtain the ninth sub-structure 459. Then, copper with a thickness of 1 μm - 5 μm is deposited on the surface of the ninth sub-structure 459 away from the transparent substrate 10 by electroplating to form the tenth sub-structure 4510. Then, an ion storage material is scrape-coated on the side of the tenth sub-structure 4510 away from the ninth sub-structure 459 to form the second functional structure 530. Among them, the ion storage material can be prepared by mixing MXene and PEDOT:PSS in a ratio of 3 / 1. In this way, the first grid structure and the second grid structure formed by the fifth conductive structure 450 and the second functional structure 530 not only have high conductivity but also have the function of ion conduction. When applied to an electrochromic device, a double-sided counter electrode can be prepared.

[0055] Optionally, on the basis of the above embodiment, continue to refer to Figure 2 , denote the depth of the first groove 210 as D1 and the width of the first groove as D2. Then, the depth and width of the first groove 210 satisfy 4 ≥ D1 / D2 ≥ 1. Denote the depth of the second groove 310 as D3 and the width of the second groove 310 as D4. Then, the depth and width of the second groove 310 satisfy 4 ≥ D3 / D4 ≥ 1.

[0056] Specifically, by setting the depth and width of the first groove 210 to satisfy 4≥D1 / D2≥1, the depth of the first groove 210 is made greater than the width of the first groove 210, so that on the basis of ensuring high conductivity of the first conductive stack structure 40 in the first groove 210, the width of the first groove 210 is reduced, thereby reducing the metal proportion and improving the light transmittance. In other words, by reducing the width of the first groove 210 and adding the reduced width to the depth of the first groove 210 in the thickness direction of the transparent substrate 10, on the basis of ensuring unchanged conductivity, the proportion of the first conductive stack structure 40 in the horizontal direction is reduced, thereby reducing the metal proportion and improving the light transmittance. Similarly, the second groove 310 has the same beneficial effects and will not be elaborated here one by one.

[0057] Based on the same inventive concept, an embodiment of the present invention further provides a method for preparing a double-sided transparent conductive film. Figure 6 is a schematic flow chart of a method for preparing a double-sided transparent conductive film provided by an embodiment of the present invention. Refer to Figure 6 , the preparation method includes:

[0058] S110. Provide a transparent substrate.

[0059] The transparent substrate includes a first surface and a second surface which are oppositely arranged. Among them, the first surface can be the front surface of the transparent substrate, and the second surface can be the back surface of the transparent substrate.

[0060] S120. Prepare a first patterned glue layer on the first surface of the transparent substrate, and prepare a second patterned glue layer on the second surface of the transparent substrate.

[0061] Patterned glue layers are provided on both the first surface and the second surface of the transparent substrate. Exemplarily, the patterned glue layer on the first surface is the first patterned glue layer, and the patterned glue layer on the second surface is the second patterned glue layer. It can be understood that the embodiment of the present invention takes the example of providing patterned glue layers on both the first surface and the second surface of the transparent substrate for illustration, but does not limit this. In other embodiments, photoresist layers can also be provided on both the first surface and the second surface of the transparent substrate.

[0062] S130. Form a plurality of first grooves that are connected and arranged in the first patterned glue layer, and fill the first conductive stack structure in the first grooves so that a plurality of first conductive stack structures are connected to form a first grid structure.

[0063] The first patterned photoresist layer can be etched by an imprinting method to form a plurality of first grooves in the first patterned photoresist layer. The plurality of first grooves communicate with each other, so that an overall grid-like trench structure is formed. For example, the grid-like trench structure is a plurality of continuous regular hexagon structures. Then, a variety of different conductive or functional materials are filled in the plurality of first grooves to form a first conductive stack structure in the first grooves. Since the plurality of first grooves communicate with each other and the overall grid-like trench structure is formed, the plurality of first conductive stack structures are electrically connected to each other to form a first grid structure. It can be understood that the first grid structure is essentially a conductive wire. Therefore, the first grid structure is opaque, and the position of the mesh of the first grid structure is a light-transmitting area.

[0064] S140. According to the plurality of first grooves in the first patterned photoresist layer, a plurality of second grooves in alignment are formed in the second patterned photoresist layer by an alignment imprinting method or a self-masking photolithography method, and a second conductive stack structure is filled in the second grooves to form a second grid structure, so that along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide.

[0065] After the first grooves and the first grid structure are prepared, taking the plurality of first grooves in the first patterned photoresist layer as a template, a plurality of aligned second grooves are formed on the second patterned photoresist layer on the second side by a high-precision alignment imprinting method or a self-masking photolithography method, that is, along the thickness direction of the transparent substrate, the first grooves and the second grooves completely coincide. Then, a variety of different conductive or functional materials are filled in the second grooves to form a second conductive stack structure in the second grooves. Since the plurality of second grooves communicate with each other and the overall grid-like trench structure is formed, the plurality of second conductive stack structures are electrically connected to each other to form a first grid structure. Since the first grooves and the second grooves completely coincide, along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide. In this way, on the one hand, since both the first side and the second side of the transparent substrate include conductive grid structures, the conductivity of the double-sided transparent conductive film is improved. On the other hand, since along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide, that is, the first grid structure and the second grid structure are made by high-precision alignment, the light-transmitting areas between them coincide, and the grid structures coincide, so that the metal duty cycle of the two is greatly reduced, thereby improving the light transmittance of the double-sided transparent conductive film on the basis of ensuring high conductivity.

[0066] In summary, in the embodiment of the present invention, a first patterned glue layer is prepared on the first surface of the transparent substrate, and a second patterned glue layer is prepared on the second surface of the transparent substrate, wherein the first surface and the second surface are arranged opposite to each other. A plurality of first grooves communicating with each other are formed in the first patterned glue layer, and a first conductive laminated structure is filled in the first grooves, so that a plurality of first conductive laminated structures are connected to form a first grid structure. According to the plurality of first grooves in the first patterned glue layer, a plurality of second grooves in alignment are formed in the second patterned glue layer by means of alignment imprinting or self-masking lithography, so that along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide. In this way, on the one hand, since both the first surface and the second surface of the transparent substrate include conductive grid structures, the conductivity of the double-sided transparent conductive film is improved. On the other hand, since along the thickness direction of the transparent substrate, the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide, that is, the first grid structure and the second grid structure are in high-precision alignment, the metal duty ratio is greatly reduced, so that on the basis of ensuring high conductivity, the light transmittance of the double-sided transparent conductive film is improved.

[0067] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A double-sided transparent conductive film, characterized in that: It includes a transparent substrate, a first patterned adhesive layer and a second patterned adhesive layer; The transparent substrate comprises a first surface and a second surface which are arranged opposite to each other, the first patterned adhesive layer is arranged on the first surface, and the second patterned adhesive layer is arranged on the second surface; A plurality of first grooves are arranged in the first patterned adhesive layer, the plurality of first grooves are arranged in communication, a first conductive stacked structure is arranged in the first groove, and the plurality of first conductive stacked structures are connected to form a first grid structure; A plurality of second grooves are arranged in the second patterned adhesive layer, the plurality of second grooves are arranged in communication, a second conductive stacked structure is arranged in the second groove, and the plurality of second conductive stacked structures are connected to form a second grid structure; Along the thickness direction of the transparent substrate, a vertical projection of the first grid structure and a vertical projection of the second grid structure coincide with each other.

2. The double-sided transparent conductive film according to claim 1, characterized in that: The first conductive stacked structure and the second conductive stacked structure both include a conductive structure or a stacked structure of a conductive structure and a functional structure.

3. The double-sided transparent conductive film according to claim 2, characterized in that: The first conductive stacked structure includes a first conductive structure, the first conductive structure includes a first substructure and a second substructure stacked, the first substructure is located on a side of the second substructure close to the transparent substrate, and the first substructure and the second substructure are made of different materials; The second conductive stacked structure includes a second conductive structure, which includes a third substructure and a fourth substructure stacked in layers. The third substructure is located on a side of the fourth substructure close to the transparent substrate, and the third substructure and the fourth substructure are made of different materials.

4. The double-sided transparent conductive film according to claim 3, characterized in that: The first substructure is made of the same material as the third substructure, and the second substructure is made of the same material as the fourth substructure.

5. The double-sided transparent conductive film according to claim 2, characterized in that: The first conductive stacked structure includes a third conductive structure, the third conductive structure includes a fifth substructure and a sixth substructure stacked, the fifth substructure is located on a side of the sixth substructure close to the transparent substrate, and the fifth substructure and the sixth substructure are made of different materials; The second conductive stacked structure includes a stacked structure of a fourth conductive structure and a first functional structure, the fourth conductive structure includes a seventh substructure and an eighth substructure, the seventh substructure is located on a side of the eighth substructure close to the transparent substrate, and the eighth substructure is located between the first functional structure and the seventh substructure.

6. The double-sided transparent conductive film according to claim 5, characterized in that: Along the thickness direction of the transparent substrate, the depth of the first groove is smaller than the depth of the second groove.

7. The double-sided transparent conductive film according to claim 2, characterized in that: The first conductive stacked structure and the second conductive stacked structure both include a stacked structure of a fifth conductive structure and a second functional structure; The fifth conductive structure includes a ninth substructure and a tenth substructure. The ninth substructure is located on a side of the tenth substructure close to the transparent substrate, and the tenth substructure is located between the ninth substructure and the second functional layer.

8. The double-sided transparent conductive film according to claim 2, characterized in that: The material of the conductive structure includes one of metal nanoparticles, metal nanowires or metal bulk materials; The material of the functional structure includes an ion storage material.

9. The double-sided transparent conductive film according to claim 1, characterized in that: The depth of the first groove is D1, and the width of the first groove is D2. Then the depth and width of the first groove satisfy 4≥D1 / D2≥1. Let the depth of the second groove be D3, and the width of the second groove be D4, then the depth and width of the second groove satisfy 4≥D3 / D4≥1.

10. A method for preparing a double-sided transparent conductive film, used for preparing the double-sided transparent conductive film according to any one of claims 1 to 9, characterized in that: The preparation method comprises: providing a transparent substrate; Preparing a first patterned adhesive layer on the first surface of the transparent substrate, and preparing a second patterned adhesive layer on the second surface of the transparent substrate, wherein the first surface and the second surface are arranged opposite to each other; Forming a plurality of first grooves connected to each other in the first patterned adhesive layer, and filling the first conductive stacked structures in the first grooves, so that the plurality of the first conductive stacked structures are connected to form a first grid structure; According to the multiple first grooves in the first patterned glue layer, multiple second grooves are formed in the second patterned glue layer by means of alignment stamping or self-mask photolithography, so that the vertical projection of the first grid structure and the vertical projection of the second grid structure coincide with each other along the thickness direction of the transparent substrate, wherein the second conductive stacked structure is filled in the second groove so that the multiple second conductive stacked structures are connected to form the second grid structure.

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