High-transmittance electric heating shielding composite film and preparation method thereof

Abstract

This invention relates to the field of transparent conductive film preparation technology, specifically a high-transmittance photoelectric heating shielding composite film and its preparation method. The composite film, from top to bottom, comprises: conductive silver paste, porous silica film I, indium tin oxide film, mesh-like electrothermal shielding film, silica film I, a transparent substrate, silica film II, and porous silica film II. This invention utilizes the gap-enhancing design of the mesh-like electrothermal shielding film to solve the problem of simultaneously achieving high visible light transmittance and low sheet resistance. The indium tin oxide film helps increase carrier transport paths and reduce the sheet resistance of the composite film; the outermost layer uses a porous silica structure, which can improve visible light transmittance. The preparation method of this invention is simple, the raw materials are readily available, and the prepared high-transmittance photoelectric heating shielding composite film combines high visible light transmittance and high electromagnetic shielding effectiveness, and also possesses electrothermal properties, making it a high-performance functional composite film.

Description

Technical Field

[0001] This invention relates to the field of transparent conductive film preparation technology, specifically a high-transparency photoelectric heating shielding composite film and its preparation method. Background Technology

[0002] Electrothermal shielding composite films are electrothermal elements that combine transparency and electromagnetic shielding, and are widely used in display windows of electronic devices. Currently, the main materials for electrothermal shielding films are transparent conductive oxides such as indium tin oxide (ITO) and fluorine-doped tin oxide (FTO), as well as metal nanowires, metal nanomesh, and graphene. These electrothermal materials utilize the Joule effect to generate heat for defrosting and defogging, and their low resistance characteristics to shield electromagnetic waves. The electrical properties of these electrothermal materials are heavily dependent on carrier concentration; higher carrier concentration results in lower sheet resistance and better heating and electromagnetic shielding effectiveness. However, in the visible light region, carriers in these electrothermal materials easily scatter photons, reducing visible light transmittance, making it impossible to simultaneously achieve low sheet resistance and high transmittance. In practical applications, excessively low visible light transmittance severely affects the brightness and visual experience of the display window, while high sheet resistance increases the heating voltage of the heater and reduces the shielding effectiveness against electromagnetic waves. Therefore, there is an urgent need to develop an electrically heated shielding composite film that combines good light transmittance and electromagnetic shielding effect. Summary of the Invention

[0003] The purpose of this invention is to provide a high-transmittance photoelectric heating shielding composite film and its preparation method, so as to simultaneously achieve high visible light transmittance and high electromagnetic shielding effectiveness.

[0004] The present invention is specifically achieved through the following technical solution: a high-transmittance photoelectric heating shielding composite film proposed in the present invention comprises, from top to bottom: conductive silver paste, porous silicon dioxide film I, indium tin oxide (ITO) film, mesh electrothermal shielding film, silicon dioxide film I, transparent substrate, silicon dioxide film II, porous silicon dioxide film II, and conductive wires are welded on the conductive silver paste.

[0005] The porous silica film I and porous silica film II have a thickness of 50~120 nm, the indium tin oxide film has a thickness of 10~20 nm, the mesh electric heating shielding film has a thickness of 100-500 nm, and the silica film I and silica film II have a thickness of 5~10 nm.

[0006] In the aforementioned high-transparency photoelectric heating shielding composite film, the transparent substrate is preferably selected from polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), polyimide (PI), flexible transparent glass, ultra-white glass, soda-lime glass, and borosilicate glass.

[0007] The aforementioned high-transparency photoelectric heating shielding composite film, wherein the mesh-like electrothermal shielding film is a film formed by silver nanowires, copper nanowires, silver nanonets, or copper nanonets, wherein the silver nanowires or copper nanowires are commercially available products, and the silver nanonets or copper nanonets are prepared using photolithography or crack template methods.

[0008] This invention also provides a method for preparing the aforementioned high-transmittance photoelectric heating shielding composite film, specifically including the following steps:

[0009] S1. A silicon dioxide thin film with a thickness of 5 ~ 10 nm is prepared on both the front and back sides of a transparent substrate by magnetron sputtering, and is defined as silicon dioxide thin film I and silicon dioxide thin film II, respectively.

[0010] S2. Prepare a mesh-like electrothermal shielding film with a thickness of 100~500 nm on the surface of the silica film I obtained in step S1. The mesh-like electrothermal shielding film is a film formed by silver nanowires, copper nanowires, silver nanomesh, or copper nanomesh.

[0011] S3. An ITO film with a thickness of 10~20 nm is prepared on the surface of the mesh-like electrothermal shielding film obtained in step S2 by magnetron sputtering.

[0012] S4. A silicon dioxide-metal oxide composite film I with a thickness of 50-120 nm is prepared on the surface of the ITO film obtained in step S3 by magnetron sputtering. A silicon dioxide-metal oxide composite film II with a thickness of 50-120 nm is prepared on the surface of the silicon dioxide film II by the same magnetron sputtering process parameters. The silicon dioxide-metal oxide composite film I and the silicon dioxide-metal oxide composite film II are made of the same material, and the metal oxide is one of aluminum oxide, copper oxide and zinc oxide.

[0013] S5. Immerse the entire film obtained in step S4 in an acidic solution for 15-30 minutes to completely remove the metal oxides in the silica-metal oxide composite film I and silica-metal oxide composite film II. Then rinse the film with deionized water and dry the film at 50°C. Silica-metal oxide composite film I becomes porous silica film I and silica-metal oxide composite film II becomes porous silica film II.

[0014] S6. A layer of conductive silver paste is printed on the surface of porous silica film I using screen printing technology, and wires are led out from the conductive silver paste to complete the preparation of high-transmittance photoelectric heating shielding composite film.

[0015] In step S5, after the entire film is immersed in the acidic solution, the metal oxides in the silica-metal oxide composite film I and silica-metal oxide composite film II react with the acid in the solution. Subsequently, after rinsing with deionized water, the metal oxides in silica-metal oxide composite film I and silica-metal oxide composite film II are removed, thereby forming a porous structure in silica-metal oxide composite film I and silica-metal oxide composite film II. This makes silica-metal oxide composite film I a porous silica film I, and silica-metal oxide composite film II a porous silica film II. The porous structure in porous silica film I and porous silica film II can significantly reduce light scattering, increasing visible light transmittance. Furthermore, it facilitates the penetration of conductive silver paste into porous silica film I and its contact with the ITO conductive layer, thus enabling the electrothermal performance of the electrothermal shielding composite film to be achieved through an applied voltage.

[0016] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, the transparent substrate is preferably selected from polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), polyimide (PI), flexible transparent glass, ultra-white glass, soda-lime glass, and borosilicate glass.

[0017] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, the magnetron sputtering process parameters in step S1 are: sputtering pressure 1 Pa, sputtering power 40 ~ 200 W, and silicon target material is selected.

[0018] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, when the mesh-like electrothermal shielding film in step S2 is a film formed by silver nanowires or copper nanowires, it is prepared by spin coating. The concentration of the silver nanowire or copper nanowire suspension is 0.8~1.5 mg / mL. During spin coating, in each cycle, the spin coater first runs at a low speed (500 r / min) for 5 s, and then runs at a high speed (2000 r / min) for 20 s. The spin coating is repeated for 4~5 cycles to obtain a silver nanowire film or a copper nanowire film. When the mesh-like electrothermal shielding film is a film formed by a silver nanomesh or a copper nanomesh, it is prepared by photolithography or a crack template method.

[0019] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, the magnetron sputtering process parameters in step S3 are as follows: sputtering pressure 1 Pa, sputtering power 80 ~ 150 W, and ITO target material is selected, with the mass ratio of indium oxide to tin oxide in the ITO target material being 9:1.

[0020] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, the magnetron sputtering process parameters in step S4 are as follows: sputtering pressure 1 Pa, sputtering power 100 ~ 250 W, and the sputtering target used is a silicon-aluminum alloy target, a silicon-copper alloy target, or a silicon-zinc alloy target. The molar ratio of silicon atoms to aluminum atoms, silicon atoms to copper atoms, or silicon atoms to zinc atoms in the sputtering target is (3-7):10.

[0021] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, the acidic solution in step S5 is selected from one of phosphoric acid solution, acetic acid solution, and citric acid solution, and the mass percentage concentration of the acidic solution is 85-95%.

[0022] In the aforementioned method for preparing a high-transmittance photoelectric heating shielding composite film, the magnetron sputtering processes in steps S1, S3, and S4 are carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0023] The high-transmittance photoelectric heating shielding composite film obtained by the aforementioned preparation method has a sheet resistance of 10-22 Ω / sq, an average transmittance of 87-96% in the range of 380-780 nm, an average electromagnetic shielding effectiveness of 17-24 dB in the range of 1-15 GHz, and can be heated to 80-120℃ at a voltage of 10 V.

[0024] Compared with existing technologies, this invention has significant advantages and beneficial effects. Through the above technical solution, this invention achieves considerable technological advancement and practicality, and has broad application value, possessing at least the following advantages:

[0025] This invention utilizes the conductivity of silver nanowires, copper nanowires, silver nanomesh, or copper nanomesh, along with the anti-reflection design of the gaps between these meshes, to overcome the challenge of simultaneously achieving high visible light transmittance and low sheet resistance. Simultaneously, an ITO film with a thickness of 10-20 nm is prepared on the surface of the silver nanowires, copper nanowires, silver nanomesh, or copper nanomesh. The ITO film, acting as a conductive layer, facilitates the increase of carrier transport paths, preventing carriers from transporting solely along the silver nanowires, copper nanowires, silver nanomesh, or copper nanomesh, thus effectively reducing the film's sheet resistance. Furthermore, the ITO layer effectively protects the mesh-like electrothermal shielding film from oxidation, thereby improving its stability. The ITO film's thickness of only 10-20 nm has minimal impact on visible light transmittance. The outermost antireflection film is made of porous silica film. The porous structure of the porous silica film can not only greatly reduce the scattering of light by the substrate and improve the transmittance of visible light, but also facilitate the penetration of conductive silver paste into the porous silica film and contact with the ITO conductive layer, thereby facilitating the realization of the film's electrothermal performance by applying an external voltage.

[0026] The preparation method of this invention is simple, and the raw materials are readily available. The prepared high-transmittance photoelectric heating shielding composite film has a sheet resistance as low as 10⁻²² Ω / sq, an average transmittance of 87-96% in the 380-780 nm range, an average electromagnetic shielding effectiveness of 17-24 dB in the 1-15 GHz range, and can be heated to 80-120°C at 10 V. Therefore, the composite film prepared by this invention combines high visible light transmittance and high electromagnetic shielding effectiveness with electrothermal properties, making it a high-performance functional composite film suitable for display windows of electronic devices requiring both electrothermal heating and electromagnetic shielding. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the high-transmittance photoelectric heating shielding composite film prepared by the present invention.

[0028] Figure 2 This is a comparison of the transmittance of the high-transmittance photoelectric heating shielding composite film (including the substrate) prepared in Example 1 and a simple PET substrate in the range of 380~780 nm.

[0029] Figure 3 The electromagnetic shielding effectiveness of the high-transmittance photoelectric heating shielding composite film (including the substrate) prepared in Example 1 is in the range of 1~15 GHz.

[0030] Figure 4 The heating temperatures of the high-transmittance photoelectric heating shielding composite film (including the substrate) prepared in Example 1 under different heating voltages are shown.

[0031] Figure 1 In the diagram, 1-conductive silver paste, 2-porous silica film I, 3-ITO film, 4-mesh electric heating shielding film, 5-silica film I, 6-transparent substrate, 7-silica film II, 8-porous silica film II, 9-wire. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise specified, all conditions in the following examples were performed under standard conditions or conditions recommended by the manufacturer. Raw materials and reagents without a specified manufacturer were all commercially available products. The silicon targets, silver nanowires, copper nanowires, ITO targets, silicon-aluminum alloy targets, silicon-copper alloy targets, silicon-zinc alloy targets, and conductive silver paste used in the following examples were all commercially available products, and the conductors used were copper wires.

[0034] Example 1

[0035] S1. A 10 nm thick silicon dioxide film is prepared on both the front and back sides of a PET flexible transparent substrate using magnetron sputtering, and these are defined as silicon dioxide film I and silicon dioxide film II, respectively. In this step, the specific magnetron sputtering process is as follows: sputtering pressure 1 Pa, sputtering power 80 W, and silicon target material is selected.

[0036] S2. A layer of silver nanowires is spin-coated onto the surface of the silica film I obtained in step S1 using a spin-coating method. The concentration of the silver nanowire suspension is 1 mg / mL. In each cycle, the spin coater first runs at a low speed (500 r / min) for 5 s, and then runs at a high speed (1500 r / min) for 20 s. The spin-coating is repeated for 4 cycles to obtain a silver nanowire film with a thickness of 250 nm.

[0037] S3. An ITO film with a thickness of 10 nm is prepared on the surface of the silver nanowire film obtained in step S2 by magnetron sputtering. The specific process of magnetron sputtering in this step is as follows: sputtering pressure 1 Pa, sputtering power 80 W, and ITO target material is selected. The mass ratio of indium oxide to tin oxide in the ITO target material is 9:1.

[0038] S4. A 100 nm thick silicon dioxide-alumina composite film I is prepared on the surface of the ITO film obtained in step S3 by magnetron sputtering. A 100 nm thick silicon dioxide-alumina composite film II is then prepared on the surface of the silicon dioxide film II using the same magnetron sputtering process parameters. In this step, the specific magnetron sputtering process is as follows: sputtering pressure 1 Pa, sputtering power 200 W, and the target material used is a silicon-aluminum alloy target with a molar ratio of silicon atoms to aluminum atoms of 2:5.

[0039] S5. Immerse the entire film obtained in step S4 in a phosphoric acid solution with a mass percentage concentration of 85% for 15 minutes to completely remove the alumina in the silica-alumina composite film I and silica-alumina composite film II. Then, take out the film, rinse it with deionized water, and dry the film surface at 50°C. Silica-alumina composite film I becomes porous silica film I, and silica-alumina composite film II becomes porous silica film II.

[0040] S6. A layer of conductive silver paste is printed on the surface of porous silica film I using screen printing technology, and wires are led out from the conductive silver paste to complete the preparation of high-transmittance photoelectric heating shielding composite film.

[0041] The magnetron sputtering processes in steps S1, S3, and S4 above need to be carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0042] Figure 1 This is a schematic diagram of the structure of the high-transparency photoelectric heating shielding composite film prepared according to the present invention. From top to bottom, the high-transparency photoelectric heating shielding composite film includes: conductive silver paste 1, porous silica film I 2, ITO film 3, mesh-like electrothermal shielding film 4, silica film I 5, transparent substrate 6, silica film II 7, and porous silica film II 8. Conductive wires 9 are soldered onto the conductive silver paste 1 using tin soldering. In this embodiment, the mesh-like electrothermal shielding film 4 is a silver nanowire film. The thicknesses of porous silica film I and porous silica film II are both 100 nm, the thickness of the ITO film is 10 nm, the thickness of the silver nanowire film is 250 nm, and the thicknesses of silica film I and silica film II are both 10 nm. The ITO film covers the silver nanowires and the silica film I located between the silver nanowires.

[0043] Figure 2 The light transmittance of the high-transmittance photoelectric heating shielding composite film prepared in this embodiment is compared with that of a simple PET substrate in the range of 380-780 nm. The average light transmittance of the high-transmittance photoelectric heating shielding composite film in the range of 380-780 nm is 91.4% (including the substrate), which is significantly higher than that of the simple PET substrate (average light transmittance of 86.9%).

[0044] The sheet resistance of the high-transmittance photoelectric heating shielding composite film prepared in this embodiment was tested to be 15.1 Ω / sq. Its electromagnetic shielding effectiveness in the 1–15 GHz range was measured using a 3656D series vector network analyzer. Figure 3 As shown, the average electromagnetic shielding effectiveness in the 1–15 GHz range is 20.2 dB.

[0045] In this embodiment, power supplies with different voltages were connected between the two wires of the high-transparency photoelectric heating shielding composite film. After 30 seconds, the temperature of the high-transparency photoelectric heating shielding composite film was measured using a thermocouple sensor. The heating temperatures of the high-transparency photoelectric heating shielding composite film under different heating voltages are as follows: Figure 4As shown, within the heating voltage range of 1~10V, the heating temperature of the electrothermal shielding composite film gradually increases with the increase of the heating voltage. At a heating voltage of 10V, its temperature can be heated to 112℃, indicating that the high-transmittance photoelectric heating shielding composite film prepared in this embodiment has good electrothermal performance.

[0046] Example 2

[0047] S1. A silicon dioxide thin film with a thickness of 10 nm is prepared on both the front and back sides of a PC substrate by magnetron sputtering, and is defined as silicon dioxide film I and silicon dioxide film II, respectively. In this step, the specific process of magnetron sputtering is as follows: sputtering pressure 1 Pa, sputtering power 200 W, and silicon target material is selected.

[0048] S2. A layer of copper nanowires is spin-coated onto the surface of the silica film I obtained in step S1 using a spin-coating method. The concentration of the copper nanowire suspension is 0.8 mg / mL. In each cycle, the spin coater first runs at a low speed (500 r / min) for 5 s, and then runs at a high speed (2000 r / min) for 20 s. The spin-coating is repeated for 4 cycles to obtain a copper nanowire film with a thickness of 200 nm.

[0049] S3. An ITO film with a thickness of 20 nm is prepared on the surface of the copper nanowire film obtained in step S2 by magnetron sputtering. The specific process of magnetron sputtering in this step is as follows: sputtering pressure 1 Pa, sputtering power 150 W, ITO target material is selected, and the mass ratio of indium oxide to tin oxide in the ITO target material is 9:1.

[0050] S4. A 120 nm thick silicon dioxide-copper oxide composite film I is prepared on the surface of the ITO film obtained in step S3 by magnetron sputtering. A 120 nm thick silicon dioxide-copper oxide composite film II is then prepared on the surface of the silicon dioxide film II using the same magnetron sputtering process parameters. In this step, the specific magnetron sputtering process is as follows: sputtering pressure 1 Pa, sputtering power 250 W, and the target material used is a silicon-copper alloy target with a silicon-copper alloy target having a silicon atom to copper atom molar ratio of 3:10.

[0051] S5. Immerse the entire film obtained in step S4 in a 90% acetic acid solution for 20 minutes to completely remove the copper oxide in the silica-copper oxide composite film I and silica-copper oxide composite film II. Then, take out the film, rinse it with deionized water, and dry the film surface at 50°C. Silica-copper oxide composite film I becomes porous silica film I, and silica-copper oxide composite film II becomes porous silica film II.

[0052] S6. A layer of conductive silver paste is printed on the surface of porous silica film I using screen printing technology, and wires are led out from the conductive silver paste to complete the preparation of high-transmittance photoelectric heating shielding composite film.

[0053] The magnetron sputtering processes in steps S1, S3, and S4 above need to be carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0054] The high-transmittance photoelectric heating shielding composite film prepared in this embodiment includes, from top to bottom: conductive silver paste, porous silica film I, ITO film, copper nanowire film, silica film I, transparent substrate, silica film II, porous silica film II, and ITO film covering copper nanowires and silica film I located in the gaps between copper nanowires.

[0055] According to the test (using the same test method as in Example 1), the sheet resistance of the high-transmittance photoelectric heating shielding composite film prepared in this example is 20.8 Ω / sq, its average transmittance in the range of 380~780 nm is 87.7% (including the substrate), its average electromagnetic shielding effectiveness in the range of 1~15 GHz is 18.6 dB, and its temperature can be heated to 82°C at a heating voltage of 10 V.

[0056] Example 3

[0057] S1. Replace the substrate with soda-lime glass with a thickness of 1.1 mm, and the rest of the process is the same as step S1 in Example 1;

[0058] S2, the same as step S2 in Example 1;

[0059] S3, the same as step S3 in Example 1;

[0060] S4. A 70 nm thick silicon dioxide-zinc oxide composite film I is prepared on the surface of the ITO film obtained in step S3 by magnetron sputtering. A 70 nm thick silicon dioxide-zinc oxide composite film II is then prepared on the surface of the silicon dioxide film II using the same magnetron sputtering process parameters. In this step, the specific magnetron sputtering process is as follows: sputtering pressure 1 Pa, sputtering power 100 W, and the target material used is a silicon-zinc alloy target with a molar ratio of silicon atoms to zinc atoms of 3:10.

[0061] S5. Same as step S5 in Example 1, the final silica-zinc oxide composite film I becomes porous silica film I, and the silica-zinc oxide composite film II becomes porous silica film II.

[0062] S6, the same as step S6 in Example 1, yields a high-transmittance photoelectric heating shielding composite film.

[0063] The magnetron sputtering processes in steps S1, S3, and S4 above need to be carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0064] The high-transmittance photoelectric heating shielding composite film prepared in this embodiment includes, from top to bottom: conductive silver paste, porous silica film I, ITO film, silver nanowire film, silica film I, transparent substrate, silica film II, porous silica film II, and ITO film covering silver nanowires and silica film I located in the gaps between silver nanowires.

[0065] According to the test (using the same test method as in Example 1), the sheet resistance of the high-transmittance photoelectric heating shielding composite film prepared in this example is 14.6 Ω / sq, its average transmittance in the range of 380~780 nm is 90.3% (including the substrate), its average electromagnetic shielding effectiveness in the range of 1~15 GHz is 22.5 dB, and its temperature can be heated to 115℃ at a heating voltage of 10 V.

[0066] Example 4

[0067] S1. Replace the substrate with soda-lime glass with a thickness of 1.1 mm, and the rest of the process is the same as step S1 in Example 2;

[0068] S2, the same as step S2 in Example 2;

[0069] S3, the same as step S3 in Example 2;

[0070] S4. A 70 nm thick silicon dioxide-alumina composite film I is prepared on the surface of the ITO film obtained in step S3 by magnetron sputtering. A 70 nm thick silicon dioxide-alumina composite film II is then prepared on the surface of the silicon dioxide film II using the same magnetron sputtering process parameters. In this step, the specific magnetron sputtering process is as follows: sputtering pressure 1 Pa, sputtering power 200 W, and the target material used is a silicon-aluminum alloy target with a molar ratio of silicon atoms to aluminum atoms of 3:5.

[0071] S5. Immerse the entire film obtained in step S4 in a phosphoric acid solution with a mass percentage concentration of 85% for 15 minutes to completely remove the alumina in the silica-alumina composite film I and silica-alumina composite film II. Then, take out the film, rinse it with deionized water, and dry the film surface at 50°C. Silica-alumina composite film I becomes porous silica film I, and silica-alumina composite film II becomes porous silica film II.

[0072] S6, the same as step S6 in Example 2, yields a high-transmittance photoelectric heating shielding composite film.

[0073] The magnetron sputtering processes in steps S1, S3, and S4 above need to be carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0074] The high-transmittance photoelectric heating shielding composite film prepared in this embodiment includes, from top to bottom: conductive silver paste, porous silica film I, ITO film, copper nanowire film, silica film I, transparent substrate, silica film II, porous silica film II, and ITO film covering copper nanowires and silica film I located in the gaps between copper nanowires.

[0075] According to the test (using the same test method as in Example 1), the sheet resistance of the high-transmittance photoelectric heating shielding composite film prepared in this example is 21.3 Ω / sq, its average transmittance in the range of 380~780 nm is 94% (including the substrate), its average electromagnetic shielding effectiveness in the range of 1~15 GHz is 17.9 dB, and its temperature can be heated to 92°C at a heating voltage of 10 V.

[0076] Example 5

[0077] S1. A 10 nm thick silicon dioxide thin film is prepared on both the front and back sides of a 1.1 mm thick soda-lime glass using magnetron sputtering. These are defined as silicon dioxide thin film I and silicon dioxide thin film II, respectively. The specific magnetron sputtering process is the same as step S1 in Example 3.

[0078] S2. A copper nanomesh film is prepared on the surface of the silicon dioxide film I obtained in step S1 using photolithography. The specific steps include:

[0079] The soda-lime glass obtained in step S1 is placed on a spin coater. 3-5 drops of photoresist are applied to the surface of silicon dioxide film I using a dropper. The spin coater is then turned on to spread the photoresist evenly. The soda-lime glass is then placed on a heating stage at 110°C for pre-baking for 150 seconds. Next, the soda-lime glass is placed on a photolithography machine. A mesh-like mask with a linewidth of 10 μm and a duty cycle (linewidth:pitch) of 10:175 is placed on the photoresist. The suction buttons are pressed sequentially, and the stage height is adjusted. After close contact, exposure is performed for 20 seconds. The exposed soda-lime glass is then immersed in a 5% sodium hydroxide developer solution for 30 seconds, followed by placement on a heating stage at 120°C for 150 seconds. Finally, a copper film is sputtered onto the surface of the photoresist and silicon dioxide film I using magnetron sputtering. After sputtering, the film is immersed in anhydrous ethanol for 30 seconds. After removing the photoresist and the copper film on the photoresist surface, a copper nanomesh film with a thickness of 500 nm was finally obtained on the surface of the soda-lime glass silica film I. The magnetron sputtering process parameters were: sputtering power 200 W, sputtering pressure 1 Pa, sputtering time 20 min, and a copper target.

[0080] S3. An ITO film with a thickness of 10 nm is prepared on the surface of the copper nanomesh film obtained in step S2 by magnetron sputtering. The specific process of magnetron sputtering is the same as step S3 in Example 3.

[0081] S4, the same as step S4 in Example 3;

[0082] S5, the same as step S5 in Example 3;

[0083] S6, the same as step S6 in Example 3.

[0084] The magnetron sputtering processes in steps S1, S3, and S4 above need to be carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0085] The high-transmittance photoelectric heating shielding composite film prepared in this embodiment includes, from top to bottom: conductive silver paste, porous silica film I, ITO film, copper nanomesh film, silica film I, transparent substrate (soda-lime glass), silica film II, porous silica film II, and ITO film covering the copper nanomesh and silica film I located in the gaps between the copper nanomesh.

[0086] According to the test (using the same test method as in Example 1), the sheet resistance of the high-transmittance photoelectric heating shielding composite film prepared in this example is 10.3 Ω / sq, its average transmittance in the range of 380~780 nm is 96% (including the substrate), its average electromagnetic shielding effectiveness in the range of 1~15 GHz is 24 dB, and its temperature can be heated to 120°C at a heating voltage of 10 V.

[0087] Example 6

[0088] S1. A 10 nm thick silicon dioxide film is prepared on both the front and back sides of a PET flexible transparent substrate using magnetron sputtering, and these are defined as silicon dioxide film I and silicon dioxide film II, respectively. The specific magnetron sputtering process is the same as step S1 in Example 1.

[0089] S2. A silver nanomesh film is prepared on the surface of the silica film I obtained in step S1. The specific steps include:

[0090] The substrate obtained in step S1 was placed on a spin coater. An acrylic emulsion (purchased and used directly without dilution) was spin-coated onto the surface of the silica film I at 500 rpm for 15 s, followed by spin-coating at 8500 rpm for 30 s. After standing for 12 h, the solvent in the acrylic emulsion evaporated, causing microcracks to form in the acrylic film, resulting in a cracked acrylic film on the surface of the silica film I. The substrate with the cracked acrylic film was then transferred to a magnetron sputtering apparatus. A 100 nm thick silver film was sputtered onto the surface of the cracked acrylic film using magnetron sputtering. The magnetron sputtering process parameters were: sputtering power 100 W, sputtering pressure 1 Pa, sputtering time 10 min, and a silver target. After sputtering, the substrate with acrylic film and silver film was immersed in acetone solution (the acetone solution was purchased and used directly without dilution) for 30 seconds. During this process, the silver film in the crack of acrylic film remained on the substrate, while the acrylic film and the silver film on its surface fell off, and finally a silver nanomesh film with a thickness of 100 nm was obtained on the surface of silica film I.

[0091] S3. An ITO film with a thickness of 10 nm is prepared on the surface of the silver nanomesh film obtained in step S2 by magnetron sputtering. The specific process of magnetron sputtering is the same as step S3 in Example 1.

[0092] S4, the same as step S4 in Example 1;

[0093] S5, the same as step S5 in Example 1;

[0094] S6, the same as step S6 in Example 1.

[0095] The magnetron sputtering processes in steps S1, S3, and S4 above need to be carried out in a mixed atmosphere of argon and oxygen, with a flow rate ratio of argon to oxygen of 30:1.3.

[0096] The high-transmittance photoelectric heating shielding composite film prepared in this embodiment includes, from top to bottom: conductive silver paste, porous silica film I, ITO film, silver nanomesh, silica film I, transparent substrate, silica film II, porous silica film II, and ITO film covering the silver nanomesh and silica film I located in the gaps between the silver nanomesh lines.

[0097] According to the test (using the same test method as in Example 1), the sheet resistance of the high-transmittance photoelectric heating shielding composite film prepared in this example is 15.3 Ω / sq, its average transmittance in the range of 380~780 nm is 91.7% (including the substrate), its average electromagnetic shielding effectiveness in the range of 1~15 GHz is 20.4 dB, and its temperature can be heated to 110°C at a heating voltage of 10 V.

[0098] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-transmittance photoelectric heating shielding composite film, characterized in that, From top to bottom, the components are: conductive silver paste, porous silica film I, indium tin oxide film, mesh electrothermal shielding film, silica film I, transparent substrate, silica film II, and porous silica film II. The mesh electrothermal shielding film is a film formed by silver nanowires, copper nanowires, silver nanomesh, or copper nanomesh.

2. The high-transmittance photoelectric heating shielding composite film as described in claim 1, characterized in that, The thickness of porous silica film I and porous silica film II is 50~120 nm, the thickness of indium tin oxide film is 10~20 nm, the thickness of mesh electric heating shielding film is 100-500 nm, and the thickness of silica film I and silica film II is 5~10 nm.

3. The high-transmittance photoelectric heating shielding composite film as described in claim 1 or 2, characterized in that, The transparent substrate is selected from one of polyethylene terephthalate, polycarbonate, polyethylene naphthalate, polyimide, flexible transparent glass, ultra-white glass, soda-lime glass, and borosilicate glass.

4. A method for preparing a high-transmittance photoelectric heating shielding composite film, characterized in that, Includes the following steps: S1. A silicon dioxide thin film with a thickness of 5~10 nm is prepared on both the front and back sides of a transparent substrate by magnetron sputtering, and is defined as silicon dioxide thin film I and silicon dioxide thin film II, respectively. S2. Prepare a mesh-like electrothermal shielding film with a thickness of 100-500 nm on the surface of the silica film I obtained in step S1. The mesh-like electrothermal shielding film is a film formed by silver nanowires, copper nanowires, silver nanomesh, or copper nanomesh. S3. An indium tin oxide thin film with a thickness of 10~20 nm is prepared on the surface of the mesh-like electrothermal shielding film obtained in step S2 by magnetron sputtering. S4. A silicon dioxide-metal oxide composite film I with a thickness of 50~120 nm is prepared on the surface of the indium tin oxide film obtained in step S3 by magnetron sputtering, and a silicon dioxide-metal oxide composite film II with a thickness of 50~120 nm is prepared on the surface of the silicon dioxide film II. The metal oxide is one of aluminum oxide, copper oxide, and zinc oxide. S5. Immerse the entire film obtained in step S4 in an acidic solution for 15-30 minutes to completely remove the metal oxides in the silica-metal oxide composite film I and silica-metal oxide composite film II. Then rinse the film with deionized water and dry it at 50°C. Silica-metal oxide composite film I becomes porous silica film I and silica-metal oxide composite film II becomes porous silica film II. S6. Using screen printing technology, a layer of conductive silver paste is printed on the surface of porous silica film I, and wires are led out to complete the preparation of high-transmittance photoelectric heating shielding composite film.

5. The method for preparing the high-transmittance photoelectric heating shielding composite film as described in claim 4, characterized in that, The process parameters for magnetron sputtering in step S1 are: sputtering pressure 1 Pa, sputtering power 40 ~ 200 W, and silicon target material is selected; in step S2, a mesh-like electrothermal shielding film is prepared by spin coating, photolithography, or crack template method.

6. The method for preparing the high-transmittance photoelectric heating shielding composite film as described in claim 4, characterized in that, The process parameters for magnetron sputtering in step S3 are: sputtering pressure 1 Pa, sputtering power 80 ~ 150 W, and indium tin oxide target material is selected, with the mass ratio of indium oxide to tin oxide in the indium tin oxide target material being 9:

1.

7. The method for preparing the high-transmittance photoelectric heating shielding composite film as described in claim 4, characterized in that, The process parameters for magnetron sputtering in step S4 are: sputtering pressure 1 Pa, sputtering power 100 ~ 250 W, and the sputtering target is a silicon-aluminum alloy target, a silicon-copper alloy target, or a silicon-zinc alloy target. The molar ratio of silicon atoms to aluminum atoms, silicon atoms to copper atoms, or silicon atoms to zinc atoms in the sputtering target is (3-7):

10.

8. The method for preparing the high-transmittance photoelectric heating shielding composite film as described in claim 4, characterized in that, The acidic solution mentioned in step S5 is selected from one of phosphoric acid solution, acetic acid solution, and citric acid solution, and the mass percentage concentration of the acidic solution is 85-95%.

9. The method for preparing the high-transmittance photoelectric heating shielding composite film as described in claim 4, characterized in that, The obtained high-transmittance photoelectric heating shielding composite film has a sheet resistance of 10-22 Ω / sq, an average transmittance of 87-96% in the range of 380-780 nm, an average electromagnetic shielding effectiveness of 17-24 dB in the range of 1-15 GHz, and can be heated to 80-120℃ at a voltage of 10 V.

Images