CN117560918A - Transparent broadband electromagnetic shielding film and preparation method thereof - Google Patents

Abstract

The invention discloses a transparent broadband electromagnetic shielding film and a preparation method thereof, wherein the electromagnetic shielding film comprises a high polymer coiled material substrate, a first metal oxide layer, a metal seed layer, a metal conducting layer and a second metal oxide layer which are stacked in sequence from bottom to top; the metal conductive layer is made of metal copper silver, and the metal seed layer is made of metal copper. According to the invention, an ultrathin metallic copper seed layer is introduced before silver film deposition, and metallic copper serving as the seed layer can improve the activation energy barrier of surface diffusion of deposited silver atoms, so that escape and diffusion of silver cores on the surface are inhibited, and construction of an ultrathin continuous metallic silver film is realized; based on the ultrathin copper-silver composite film as a main body, the conductive oxide film structures are clamped at two sides, so that the electromagnetic wave in the range of 8-40 GHZ can be efficiently shielded, and meanwhile, the higher transmittance in the visible light range can be realized.

Description

Transparent broadband electromagnetic shielding film and preparation method thereof

Technical Field

The invention relates to the field of electromagnetic shielding materials, in particular to a transparent broadband electromagnetic shielding film and a preparation method thereof.

Background

The rapid rise of microwave wireless communication, modern electronic technology and highly integrated circuits causes serious electromagnetic energy pollution, and long-term strong electromagnetic radiation is harmful to human health, which may cause various diseases such as cancers and insomnia. Therefore, the elimination of harmful electromagnetic radiation is critical to prevent the sensitive circuits from being disturbed and to maintain a healthy living environment. Among them, a metal thin film is a mainstream scheme of a transparent conductive shielding material, and among all metals, silver is the most widely used material due to its ultra-high conductivity and the lowest optical loss. However, in order to improve the optical transmittance, the thinner the thickness of the metallic silver is, the better. However, due to the characteristic that the film is in a three-dimensional growth mode in the initial growth stage, the roughness of the three-dimensional island structure of the surface is larger when the thickness of the single-layer silver film is lower, and the electromagnetic shielding performance is reduced when the surface roughness is high. Therefore, the construction of a silver thin film with low surface roughness on a very thin thickness dimension is of great importance for the preparation of a silver thin film having both high transmittance and high electromagnetic shielding properties.

In summary, the invention provides a novel silver-based transparent broadband electromagnetic shielding film structure and a film forming scheme: the ultrathin metallic copper seed layer is introduced before silver film deposition, and the metallic copper serving as the seed layer can improve the activation energy barrier of surface diffusion of deposited silver atoms, so that escape and diffusion of silver cores on the surface are inhibited, and the construction of the ultrathin continuous metallic silver film is realized. Based on an ultrathin copper-silver composite film as a main body, the two sides are clamped with conductive oxide film structures so as to realize high-efficiency shielding of electromagnetic waves in the range of 8-40 GHZ, and simultaneously realize higher transmittance in the visible light range, thereby solving the problem of compromise between the optical transmittance and electromagnetic shielding performance of the traditional silver-based electromagnetic shielding material.

Disclosure of Invention

The invention aims to solve the technical problem of providing a transparent broadband electromagnetic shielding film and a preparation method thereof aiming at the defects in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme: a transparent broadband electromagnetic shielding film comprises a high polymer coiled material substrate, a first metal oxide layer, a metal seed layer, a metal conducting layer and a second metal oxide layer which are stacked in sequence from bottom to top;

the metal conductive layer is made of metal copper silver, and the metal seed layer is made of metal copper.

Preferably, the metal conductive layer and the metal seed layer are prepared by a roll-to-roll magnetron sputtering process.

Preferably, the first metal oxide layer and the second metal oxide layer are at least one of indium oxide, tin oxide, zinc oxide, niobium oxide, tantalum oxide, and titanium oxide or a combination thereof.

Preferably, the polymer coiled material substrate is coiled material formed by a mixture composed of one or more of the following materials: polyethylene naphthalate, polyethylene terephthalate, cellulose triacetate, cycloolefin copolymers, cycloolefin polymers, polycarbonates, polyimides.

Preferably, the thickness of the metal conductive layer is 5-15nm, and the thickness of the metal seed layer is 0.05-0.5 nm.

Preferably, the thicknesses of the first metal oxide layer and the second metal oxide layer are both 30-60nm, and the refractive indexes n at 550nm are all satisfied: n is more than or equal to 1.8 and less than or equal to 3.5.

The invention also provides a preparation method of the transparent broadband electromagnetic shielding film, which comprises the following steps:

s1, preparing a first metal oxide layer on the surface of a polymer coiled material substrate through a roll-to-roll magnetron sputtering process;

s2, injecting argon with the constant power of 6-20w into a roll-to-roll sputtering system by using a copper target pulse direct current sputtering method through a gas flow controller, and preparing a metal seed layer on the surface of the first metal oxide layer;

s3, injecting 50-200sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 200-600w, and preparing a metal conductive layer on the surface of the metal seed layer;

s4, preparing a second metal oxide layer on the surface of the metal conductive layer through a roll-to-roll magnetron sputtering process, so that the transparent broadband electromagnetic shielding film is obtained.

Preferably, the preparation method of the transparent broadband electromagnetic shielding film comprises the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a polymer coiled material substrate to obtain a first metal oxide layer with the thickness of 40 nm; the polymer coiled material substrate is a PET substrate with the thickness of 50 um;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 6w, and preparing a metal seed layer with the thickness of 0.05nm on the surface of the first metal oxide layer;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conductive layer with the thickness of 8nm on the surface of the metal seed layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

Preferably, the preparation method of the transparent broadband electromagnetic shielding film comprises the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a polymer coiled material substrate to obtain a first metal oxide layer with the thickness of 40 nm; the polymer coiled material substrate is a PET substrate with the thickness of 50 um;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 10w, and preparing a metal seed layer with the thickness of 0.1nm on the surface of the first metal oxide layer;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conductive layer with the thickness of 8nm on the surface of the metal seed layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

Preferably, the preparation method of the transparent broadband electromagnetic shielding film comprises the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a polymer coiled material substrate to obtain a first metal oxide layer with the thickness of 40 nm; the polymer coiled material substrate is a PET substrate with the thickness of 50 um;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 20w, and preparing a metal seed layer with the thickness of 0.3nm on the surface of the first metal oxide layer;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conductive layer with the thickness of 8nm on the surface of the metal seed layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

The beneficial effects of the invention are as follows:

the invention provides a transparent broadband electromagnetic shielding film and a preparation method thereof, wherein an ultrathin metallic copper seed layer is introduced before silver film deposition, and metallic copper serving as the seed layer can improve the activation energy barrier of surface diffusion of deposited silver atoms, so that escape and diffusion of silver cores on the surface are inhibited, and the construction of an ultrathin continuous metallic silver film is realized; based on the ultrathin copper-silver composite film as a main body, the conductive oxide film structures are clamped at two sides, so that the electromagnetic wave in the range of 8-40 GHZ can be efficiently shielded, and meanwhile, the higher transmittance in the visible light range can be realized; compared with the traditional ITO/Ag/ITO electromagnetic shielding film, the ITO/Cu/Ag/ITO structure transparent broadband electromagnetic shielding film has the advantages that the visible light transmittance and the electromagnetic shielding efficiency are improved, and the transparent broadband electromagnetic shielding film has important significance for solving the problem of considering both the optical transmittance and the electromagnetic shielding performance of the traditional silver-based electromagnetic shielding material.

Drawings

FIG. 1 is a schematic structural view of a transparent broadband electromagnetic shielding film according to the present invention;

fig. 2 is a schematic structural view of the transparent broadband electromagnetic shielding film prepared in example 1;

fig. 3 is a schematic structural view of the transparent broadband electromagnetic shielding film prepared in example 2;

fig. 4 is a schematic structural view of the transparent broadband electromagnetic shielding film prepared in example 3;

fig. 5 is a schematic structural view of the transparent broadband electromagnetic shielding film prepared in comparative example 1.

Fig. 6 is a surface atomic force microscope scanning (AFM) image of the transparent broadband electromagnetic shielding films prepared in examples 1-3 and comparative example 1.

Reference numerals illustrate:

1-a polymeric web substrate; 2-a first metal oxide layer; 3-a metal seed layer; 4-a metal conductive layer; 5-a second metal oxide layer.

Detailed Description

The present invention is described in further detail below with reference to examples to enable those skilled in the art to practice the same by referring to the description.

It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

The test methods used in the following examples are conventional methods unless otherwise specified. The material reagents and the like used in the following examples are commercially available unless otherwise specified. The following examples were conducted under conventional conditions or conditions recommended by the manufacturer, without specifying the specific conditions. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

Referring to fig. 1, in a first aspect of the present invention, a transparent broadband electromagnetic shielding film is provided, which includes a polymeric web substrate 1, a first metal oxide layer 2, a metal seed layer 3, a metal conductive layer 4, and a second metal oxide layer 5 stacked in this order from bottom to top;

the metal conductive layer 4 is made of metal copper silver, and the metal seed layer 3 is made of metal copper. In a preferred embodiment, the metal conductive layer 4 and the metal seed layer 3 are both prepared by a roll-to-roll magnetron sputtering process.

The first metal oxide layer 2 and the second metal oxide layer 5 serve as a bottom layer and an outermost layer of the transparent broadband electromagnetic shielding film, and in a preferred embodiment, the constituent materials thereof are at least one of indium oxide (InOx), tin oxide (SnOx), zinc oxide (ZnOx), niobium oxide (NbOx), tantalum oxide (Ta 2O 5), and titanium oxide (TiOx), or a combination thereof.

In a preferred embodiment, the polymeric web substrate 1 is a web of a mixture of one or more of the following materials: polyethylene naphthalate (PEN), polyethylene terephthalate (PET), cellulose Triacetate (TAC), cyclic olefin Copolymer (COP), cyclic olefin polymer (COC), polycarbonate (PC), polyimide (PI).

In a preferred embodiment, the thickness of the metal conductive layer 4 is 5-15nm and the thickness of the metal seed layer 3 (X) is 0.05-0.5 nm.

In a preferred embodiment, the thickness of the first metal oxide layer 2 and the second metal oxide layer 5 are both 30-60nm, and the refractive index n at 550nm is both: n is more than or equal to 1.8 and less than or equal to 3.5.

In a second aspect of the present invention, there is provided a method for preparing the transparent broadband electromagnetic shielding film as above, comprising the steps of:

s1, preparing a first metal oxide layer 2 on the surface of a polymer coiled material substrate 1 through a roll-to-roll magnetron sputtering process;

s2, injecting argon with the constant power of 6-20w into a roll-to-roll sputtering system by using a copper target pulse direct current sputtering method through a gas flow controller, and preparing a metal seed layer 3 on the surface of the first metal oxide layer 2;

s3, injecting 50-200sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 200-600w, and preparing a metal conductive layer 4 on the surface of the metal seed layer 3;

s4, preparing a second metal oxide layer 5 on the surface of the metal conductive layer 4 through a roll-to-roll magnetron sputtering process, so that the transparent broadband electromagnetic shielding film is obtained.

The foregoing is a general inventive concept and the following detailed examples and comparative examples are provided on the basis thereof to further illustrate the invention.

Example 1

Referring to fig. 2, the embodiment provides a transparent broadband electromagnetic shielding film, which includes a polymer coiled material substrate, a first metal oxide layer, a metal seed layer, a metal conductive layer and a second metal oxide layer stacked in sequence from bottom to top, and the preparation method of the transparent broadband electromagnetic shielding film includes the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a colorless transparent polyethylene terephthalate substrate (PET) with the thickness of 50um to obtain a first metal oxide layer with the thickness of 40nm, namely Indium Tin Oxide (ITO) with the thickness of 40 nm;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 6w, and preparing a metal seed layer with the thickness of 0.05nm on the surface of the first metal oxide layer, namely, preparing a metal copper seed layer with the thickness of 0.05 nm;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conducting layer with the thickness of 8nm on the surface of the metal seed layer, namely, metal silver with the thickness of 8nm on the metal conducting layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

Example 2

Referring to fig. 3, the embodiment provides a transparent broadband electromagnetic shielding film, which includes a polymer coiled material substrate, a first metal oxide layer, a metal seed layer, a metal conductive layer and a second metal oxide layer stacked in sequence from bottom to top, and the preparation method of the transparent broadband electromagnetic shielding film includes the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a colorless transparent polyethylene terephthalate substrate (PET) with the thickness of 50um to obtain a first metal oxide layer with the thickness of 40nm, namely Indium Tin Oxide (ITO) with the thickness of 40 nm;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 10w, and preparing a metal seed layer with the thickness of 0.1nm on the surface of the first metal oxide layer, namely, preparing a metal copper seed layer with the thickness of 0.1 nm;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conducting layer with the thickness of 8nm on the surface of the metal seed layer, namely, metal silver with the thickness of 8nm on the metal conducting layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

Example 3

Referring to fig. 4, the embodiment provides a transparent broadband electromagnetic shielding film, which includes a polymer coiled material substrate, a first metal oxide layer, a metal seed layer, a metal conductive layer and a second metal oxide layer stacked in sequence from bottom to top, and the preparation method of the transparent broadband electromagnetic shielding film includes the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a colorless transparent polyethylene terephthalate substrate (PET) with the thickness of 50um to obtain a first metal oxide layer with the thickness of 40nm, namely Indium Tin Oxide (ITO) with the thickness of 40 nm;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 20w, and preparing a metal seed layer with the thickness of 0.3nm on the surface of the first metal oxide layer, namely, preparing a metal copper seed layer with the thickness of 0.3 nm;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conducting layer with the thickness of 8nm on the surface of the metal seed layer, namely, metal silver with the thickness of 8nm on the metal conducting layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

Comparative example 1

Referring to fig. 5, the present embodiment provides a transparent broadband electromagnetic shielding film, which includes a polymer coiled material substrate, a first metal oxide layer, a metal conductive layer and a second metal oxide layer stacked in sequence from bottom to top, and the preparation method of the transparent broadband electromagnetic shielding film includes the following steps:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a colorless transparent polyethylene terephthalate substrate (PET) with the thickness of 50um to obtain a first metal oxide layer with the thickness of 40nm, namely Indium Tin Oxide (ITO) with the thickness of 40 nm;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 600w, and preparing a metal conducting layer with the thickness of 8nm on the surface of the first metal oxide, namely, metal silver with the thickness of 8nm on the metal conducting layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

The transparent broadband electromagnetic shielding films prepared in examples 1 to 3 and comparative example 1 were subjected to the following performance test:

(1) Electromagnetic shielding performance measurement, namely measuring the average electromagnetic shielding performance of 8-40 GHZ wave bands by referring to the standard GJB 6190-2008;

(2) The average light transmittance of the visible light region of 400-800 nm is tested, the test method is a transmission method, and specific test standards refer to GB/T7962.12-2010;

(3) The method for testing the surface roughness is an atomic force scanning electron microscope method, and specific testing standards refer to GB/T31227-2014.

The test results are shown in table 1 below:

TABLE 1

Classification	Example 1	Example 2	Example 3	Comparative example 1
					400-800 nm visible light average transmittance (%)	87.75	90.77	90.43	82.22
8-40 GHZ average electromagnetic shielding effectiveness (dB)	17.45	21.16	21.25	14.63
					Surface roughness (nm) of silver metal layer	3.87	1.32	1.35	5.46

As can be seen from comparing the examples with the comparative examples, the transmittance, shielding effectiveness, and surface roughness in the examples are all superior to those in comparative example 1, because the presence of the metallic copper seed layer induces the growth of high density silver clusters at the initial stage of silver film deposition and forms a smooth and uniform silver film with a lower penetration threshold. Of these, example 2 is optimal because neither too thick nor too thin copper seed layer performs optimally, i.e., a metallic copper seed layer of approximately 0.1nm thickness is optimal for forming a continuous ultrathin silver film. Therefore, compared with comparative example 1, the products of examples 1-3 of the present invention have significantly improved visible light transmittance and electromagnetic shielding effectiveness, and have important significance in solving the problem of compromise between the optical transmittance and electromagnetic shielding performance of the conventional silver-based electromagnetic shielding material.

Although embodiments of the present invention have been disclosed above, it is not limited to the use of the description and embodiments, it is well suited to various fields of use for the invention, and further modifications may be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the particular details without departing from the general concepts defined in the claims and the equivalents thereof.

Claims (10)

1. The transparent broadband electromagnetic shielding film is characterized by comprising a high polymer coiled material substrate, a first metal oxide layer, a metal seed layer, a metal conductive layer and a second metal oxide layer which are stacked in sequence from bottom to top;

the metal conductive layer is made of metal copper silver, and the metal seed layer is made of metal copper.

2. The transparent broadband electromagnetic shielding film according to claim 1, wherein the metal conductive layer and the metal seed layer are prepared by a roll-to-roll magnetron sputtering process.

3. The transparent broadband electromagnetic shielding film according to claim 1, wherein the first metal oxide layer and the second metal oxide layer are each at least one of indium oxide, tin oxide, zinc oxide, niobium oxide, tantalum oxide, and titanium oxide, or a combination thereof.

4. The transparent broadband electromagnetic shielding film according to claim 1, wherein the polymeric web substrate is a web of a mixture of one or more of the following materials: polyethylene naphthalate, polyethylene terephthalate, cellulose triacetate, cycloolefin copolymers, cycloolefin polymers, polycarbonates, polyimides.

5. The transparent broadband electromagnetic shielding film according to claim 2, wherein the thickness of the metal conductive layer is 5-15nm, and the thickness of the metal seed layer is 0.05-0.5 nm.

6. The transparent broadband electromagnetic shielding film according to claim 3, wherein the thicknesses of the first metal oxide layer and the second metal oxide layer are each 30-60nm, and the refractive indexes n at 550nm are each satisfied: n is more than or equal to 1.8 and less than or equal to 3.5.

7. A method for producing the transparent broadband electromagnetic shielding film according to any one of claims 1 to 6, comprising the steps of:

s1, preparing a first metal oxide layer on the surface of a polymer coiled material substrate through a roll-to-roll magnetron sputtering process;

s2, injecting argon with the constant power of 6-20w into a roll-to-roll sputtering system by using a copper target pulse direct current sputtering method through a gas flow controller, and preparing a metal seed layer on the surface of the first metal oxide layer;

s3, injecting 50-200sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 200-600w, and preparing a metal conductive layer on the surface of the metal seed layer;

s4, preparing a second metal oxide layer on the surface of the metal conductive layer through a roll-to-roll magnetron sputtering process, so that the transparent broadband electromagnetic shielding film is obtained.

8. The method for preparing a transparent broadband electromagnetic shielding film according to claim 7, comprising the steps of:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a polymer coiled material substrate to obtain a first metal oxide layer with the thickness of 40 nm; the polymer coiled material substrate is a PET substrate with the thickness of 50 um;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 6w, and preparing a metal seed layer with the thickness of 0.05nm on the surface of the first metal oxide layer;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conductive layer with the thickness of 8nm on the surface of the metal seed layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

9. The method for preparing a transparent broadband electromagnetic shielding film according to claim 7, comprising the steps of:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a polymer coiled material substrate to obtain a first metal oxide layer with the thickness of 40 nm; the polymer coiled material substrate is a PET substrate with the thickness of 50 um;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 10w, and preparing a metal seed layer with the thickness of 0.1nm on the surface of the first metal oxide layer;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conductive layer with the thickness of 8nm on the surface of the metal seed layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.

10. The method for preparing a transparent broadband electromagnetic shielding film according to claim 7, comprising the steps of:

s1, performing single-target direct current sputtering by using an indium tin oxide target material, wherein the constant power is 6000w, injecting 200sccm argon gas into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of a polymer coiled material substrate to obtain a first metal oxide layer with the thickness of 40 nm; the polymer coiled material substrate is a PET substrate with the thickness of 50 um;

s2, injecting 80sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a copper target pulse direct current sputtering method with constant power of 20w, and preparing a metal seed layer with the thickness of 0.3nm on the surface of the first metal oxide layer;

s3, injecting 100sccm argon into a roll-to-roll sputtering system through a gas flow controller by utilizing a silver target pulse direct current sputtering method with constant power of 400w, and preparing a metal conductive layer with the thickness of 8nm on the surface of the metal seed layer;

s4, performing single-target direct current sputtering by using an indium tin oxide target material, injecting 200sccm argon into a roll-to-roll sputtering system through a gas flow controller, and performing sputtering on the surface of the metal conductive layer to obtain a second metal oxide layer with the thickness of 40nm, wherein the constant power is 6000 w.