A metal nanowire transparent conductive film with high stability and an electronic device

Abstract

The present invention belongs to the technical field of transparent conductive films, and specifically discloses a highly stable metal nanowire transparent conductive film and electronic device. The transparent conductive film includes a base layer, a conductive layer, and an overcoat. The conductive layer includes metal nanowires. The transparent conductive film also includes a light stabilizer. The light stabilizer includes a vanadium oxide compound, wherein the vanadium in the vanadium oxide compound has a valence of +2 to +5, but not +5. The light stabilizer is contained in at least one of the base layer, the conductive layer, and the overcoat. Compared to traditional ITO conductive films, the transparent conductive film of the present invention has beneficial characteristics such as high transparency, strong bending resistance, good stability, and resistance to ultraviolet radiation. This expands the application of transparent conductive films in electronic devices such as outdoor applications, thin-film solar cells, transparent thin-film heaters, transparent electromagnetic shielding, automotive optoelectronic products, and precision ultraviolet optical devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of transparent conductive films, and in particular relates to a metal nanowire transparent conductive film with high stability and an electronic device. Background Art

[0002] Transparent conductive film (TCF), also known as transparent electrode, refers to a thin film structure with high transparency and good conductivity in the visible light band (400nm-800nm). It can be used in touch screens, smart dimming films, LEDs, flexible displays, smart wearables, electronic skin, biosensors, transparent electromagnetic shielding, solar thin film batteries, and transparent thin film heating devices. It is difficult for general conductive materials to have both good conductivity and light transmittance. Currently, the most widely used transparent conductive oxide is indium-doped tin oxide (ITO), which has a conductivity comparable to that of metal and a transmittance of over 90% in the visible light region. However, due to its inherent ceramic brittleness, ITO needs to be deposited by sputtering, making it difficult to improve manufacturing efficiency. In addition, the brittleness of ceramics limits the application of ITO in curved, foldable, flexible, electronic skin, and smart wearables.

[0003] Metal nanowire transparent conductive films offer advantages such as excellent conductivity, high light transmittance, resistance to bending and stretching, and relatively stable physical and chemical properties. They possess diverse application potential and irreplaceable advantages. Metal nanowires include, but are not limited to, at least one of gold, silver, copper, iron, cobalt, nickel, and aluminum, as well as composite metal nanowires (doped and core-shell) composed of two or more metals. Due to the combined effects of high temperatures, light (UV radiation), moisture, and oxygen, metal oxidation and migration can reduce the stability of the metal nanowires and their conductive layers, leading to even rapid aging and failure. Therefore, the stability of metal nanowire transparent conductive films, their devices, and products remains a pressing challenge.

[0004] Currently, researchers believe that the most effective strategy is to encapsulate and protect the metal nanowire conductive layer, effectively blocking water and oxygen, thereby improving the stability of metal nanowire transparent conductive films, devices, and products in indoor applications. However, under outdoor lighting conditions (especially ultraviolet light), traditional encapsulation layers cannot effectively block light. Metal atoms on the surface of metal nanowires that absorb UV photons are prone to plasma resonance, causing metal atom diffusion and migration. The photothermal effect further accelerates this process, ultimately causing the transparent electrode to fail due to spherical fracture or short circuiting of the metal nanowires.

[0005] Patent publication number CN106660312B discloses improved light stability for a nanowire-based transparent conductor. A light-stabilized optical stack is disclosed, comprising a transparent conductive film formed from silver nanostructures or a silver mesh, the conductive film comprising silver nanowires, and a light stabilizer comprising a transition metal salt or transition coordination complex of Fe, Co, Mn, or V. The optical stack has a light-exposed region, wherein metal atoms on the surface of the metal nanowires absorb light and undergo plasmon resonance, resulting in the formation of photoactive species in the optical stack and an increase in sheet resistance. The light stabilizer acts as a catalyst to accelerate the reaction of the photoactive species with an organic material present in the optical stack, causing the photoactive species to be consumed by the organic material before interacting with the silver nanowires. However, the light stabilizer does not effectively improve the absorption of light by the metal nanowires, but rather utilizes the organic material to consume the photoactive species. This can accelerate oxidation reactions of the organic material under the influence of external factors such as high temperature and light in outdoor applications, leading to adverse effects such as organic material aging.

[0006] Patent document CN109804439B discloses a stabilized sparse metal conductive film comprising a substrate, a sparse metal conductive layer supported by the substrate, and a coating adjacent to the sparse metal conductive layer. The sparse metal conductive layer comprises a molten metal nanostructure network. A stabilizer is incorporated into the coating adjacent to the sparse metal conductive layer, the coating comprising a polymer matrix and a vanadium + 5 stabilizing composition. However, because the presence of the vanadium + 5 stabilizing composition inhibits the chemical melting process of the metal nanowires, the vanadium + 5 stabilizing composition cannot be applied to the sparse metal conductive layer. Similarly, the sparse metal conductive layer is enhanced in terms of photostability by adding a complex of a transition metal salt Co to the sparse metal conductive layer, thereby consuming the photoactive species by the organic material before interacting with the silver nanowires. Similarly, the photostabilizer does not effectively improve the metal nanowires' absorption of light.

[0007] In summary, there is an urgent need to provide a metal nanowire transparent conductive film with high stability and a preparation method, which can effectively improve the defect of metal nanowires absorbing light and causing an increase in sheet resistance. Summary of the Invention

[0008] The object of the present invention is to provide a metal nanowire transparent conductive film and an electronic device with high stability, which can effectively improve the defect of the metal nanowires absorbing light and causing an increase in sheet resistance.

[0009] In a first aspect, the present invention provides a transparent conductive film, comprising a base layer, a conductive layer, and an outer covering layer, wherein the conductive layer comprises metal nanowires, and the transparent conductive film further comprises a light stabilizer, wherein the light stabilizer comprises a vanadium oxide compound, wherein the vanadium in the vanadium oxide compound has a valence of +2 to +5, and is not +5, and the light stabilizer is contained in at least one of the base layer, the conductive layer, and the outer covering layer.

[0010] Optionally, the metal nanowires include at least one of gold, silver, copper, iron, cobalt, nickel, aluminum, indium, tin, platinum, palladium or titanium nanowires;

[0011] And / or, the metal nanowires include composite metal nanowires composed of at least two metals selected from the group consisting of gold, silver, copper, iron, cobalt, nickel, aluminum, indium, tin, platinum, palladium or titanium.

[0012] Optionally, the vanadium oxide compound includes at least one of strontium vanadate, lanthanum vanadate, cerium vanadate, calcium vanadate, yttrium vanadate, praseodymium vanadate, neodymium vanadate, vanadium dioxide or vanadium trioxide.

[0013] Optionally, the transparent conductive film further comprises an optically transparent adhesive layer and / or a top protective layer, and the light stabilizer is contained in at least one of the base layer, the conductive layer, the overcoat layer, the optically transparent adhesive layer or the top protective layer.

[0014] Optionally, the outer covering layer is composed of a composition including a polymer; and the light stabilizer is contained in at least one of the conductive layer and the outer covering layer.

[0015] Optionally, the conductive layer is prepared from a solution comprising the metal nanowires and the light stabilizer, and the content of the light stabilizer is 0.001 wt % to 3 wt % of the solution;

[0016] And / or, the outer coating layer is prepared from a solution comprising a polymer and the light stabilizer, and the content of the light stabilizer is 0.001 wt % to 3 wt % of the solution.

[0017] Optionally, the vanadium oxide compound is a micron or nanometer material, and the micron or nanometer material includes at least one of micron or nanometer particles, micron or nanometer fibers, micron or nanometer sheets, or micron or nanometer spheres.

[0018] Optionally, the metal nanowires include silver nanowires.

[0019] Optionally, the sheet resistance of the transparent conductive film does not exceed 40 ohms / square, the visible light transmittance is at least 85%, and the haze value does not exceed 8%. After 1000 hours of ultraviolet irradiation, the sheet resistance of the transparent conductive film does not exceed 100 ohms / square, the visible light transmittance is at least 85%, and the haze value does not exceed 8%.

[0020] Optionally, the ultraviolet irradiation uses a UVB light source with a wavelength of 313 nm, the distance between the surface of the transparent conductive film and the light source is 5 cm, and the ultraviolet light energy density on the surface of the transparent conductive film reaches 0.5 mW / cm 2 .

[0021] In a second aspect, the present invention provides an electronic device, comprising the transparent conductive film described in any one of the above items.

[0022] In summary, the present invention has at least one of the following beneficial effects:

[0023] The metal nanowire transparent conductive film provided by the present invention utilizes a vanadium oxide compound with a valence of +2 to +5, but not +5, to enhance the stability of the metal nanowire transparent conductive film. The vanadium oxide compound is added to at least one of the key metal nanowire conductive layers and / or the base layer and outer coating in the transparent conductive film. Compared with metal nanowire transparent conductive films without the vanadium oxide compound, the overall stability of the transparent conductive film is significantly improved, particularly in terms of resistance to UV radiation. The vanadium oxide compound / metal nanowire transparent conductive film exhibits resistance to UV radiation, sweat, and ethanol immersion at room temperature that is far superior to commercial transparent conductive films and approaches that of ITO. It also possesses excellent optical, thermal, and chemical stability, expanding its application in outdoor applications, thin-film solar cells, transparent film heaters, transparent electromagnetic shielding, automotive optoelectronic products, and precision UV optical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 is a schematic structural diagram of a transparent conductive film according to an embodiment of the present invention;

[0026] Figure 2 This is a comparison chart of the photoelectric properties (sheet resistance Rs, visible light transmittance Tvis, and haze H) of silver nanowire transparent conductive films without strontium vanadate added in Example 1 and with strontium vanadate added in Example 4 of the present invention after 1000 hours of ultraviolet irradiation;

[0027] Figure 3This is a comparison chart of the photoelectric properties (sheet resistance Rs, visible light transmittance Tvis, and haze H) of different types of vanadium oxide / silver nanowire composite transparent conductive films of Example 1 and Examples 4-8 of the present invention after 1000 hours of ultraviolet irradiation;

[0028] Figure 4 This is a comparison chart of the photoelectric performance (sheet resistance Rs, visible light transmittance Tvis, and haze H) of different forms of strontium vanadate / silver nanowire composite transparent conductive films of Examples 4 and 9 of the present invention after 1000 hours of ultraviolet irradiation;

[0029] Figure 5 This is a comparison chart of the photoelectric properties (sheet resistance Rs, visible light transmittance Tvis, and haze H) of the strontium vanadate / silver nanowire composite transparent conductive films of Examples 1, 4, 10, and 11 of the present invention with different addition amounts after 500 hours of ultraviolet irradiation;

[0030] Figure 6 This is a comparison chart of the optoelectronic properties (square resistance Rs, visible light transmittance Tvis, haze H) of silver nanowire transparent conductive films of Example 1 of the present invention without adding strontium vanadate, Example 4 with adding strontium vanadate, and Comparative Examples 1 and 2 with adding +5-valent vanadium oxide (NaVO3 and SrV2O6), after 1000 hours of ultraviolet irradiation. DETAILED DESCRIPTION

[0031] The present invention provides a metal nanowire transparent conductive film and an electronic device with high stability. In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention. It should be noted that the directional terms such as up, down, left, right, front, back, inside, and outside that appear or will appear in the text of the present invention are based only on the drawings of the present invention and are not specific limitations of the present invention.

[0032] Reference Figure 1A typical transparent conductive film includes a multilayer structure, which generally includes a substrate 100, a conductive layer 110, an overcoat (OC) 120, an optional optically clear adhesive layer (OCA) 130, and an optional top protective layer 140. It should be understood that not all embodiments include all layers. The overcoat 120 can be one or two layers, deposited on the upper and / or lower sides of the conductive layer 110 to protect the conductive layer 110. Optional means that the layer is included or not included. For example, the optional optically clear adhesive layer 130 may be included or not included to bond the adjacent upper and lower layers. The optional top protective layer 140 may be included or not included to protect the multilayer structure. The substrate 100 is used to provide support. The conductive layer 110 includes metal nanowires in an interconnected structure or a network structure. The metal nanowires include but are not limited to at least one of gold, silver, copper, iron, cobalt, nickel, aluminum, indium, tin, platinum, palladium or titanium nanowires, as well as composite metal nanowires (doped type and core-shell type) composed of two or more of the aforementioned metals. Metal nanowire transparent conductive films are widely used in various electronic devices due to their high conductivity, transparency and flexibility, such as electronic displays (liquid crystal displays, touch screens and flexible displays), solar cells, optoelectronic devices (photoelectric conductive converters), and organic light-emitting diodes (OLEDs). Silver nanowire transparent conductive films are especially widely used due to their optimal conductivity.

[0033] The substrate 100 can be made of a material that is translucent to visible light, for example, a durable support layer is formed by one or more appropriate materials such as quartz, sapphire, glass or plastic. Plastics can be listed as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polysulfone ether (PES), polycarbonate (PC), polyetherimide (PEI), polyacrylate (PA), polydimethoxysiloxane (PDMS), polyvinyl alcohol (PVA), their copolymers or their mixtures, and other suitable optically transparent polymers with high transparency, low haze and good protective support, all of which can be used as materials for the substrate 100 of the present invention. The thickness of the substrate 100 is not particularly limited and can be appropriately selected according to the purpose. In some embodiments of the present invention, the thickness of the substrate 100 can be 5μm to 1.5mm, further, 10μm to 1mm, and further 50μm to 500μm.

[0034] Conductive layer 110 is formed from a dispersion (solution) containing metal nanowires. The dispersion includes a solvent, and conventional additives in the art may be added to enhance the dispersion's ability to form conductive layer 110. Solvents used in the metal nanowire dispersion may include aqueous solvents, organic solvents, or mixtures thereof, including water, alcohols (ethanol, isopropyl alcohol, isobutyl alcohol, n-butanol, or tert-butanol), ketones (methyl ethyl ketone, methyl isobutyl ketone), esters (ethyl acetate, butyl acetate, ethyl lactate), ethers (glycol ethers), aromatic compounds (toluene), alkanes (hexane), and mixtures thereof. Additives include dispersants, surfactants, binders, thickeners, antioxidants, anti-settling agents, viscosity modifiers, defoamers, UV stabilizers, fillers, softeners, and mixtures thereof. In some embodiments of the present invention, the metal nanowire content is 0.001 to 3 wt% of the dispersion, optionally 0.003 to 2 wt%, and further optionally 0.005 to 1 wt%. The amount of additives is selected based on actual needs, typically not exceeding 3 wt% of the dispersion, but is not specifically limited. The metal nanowires can be made of gold, silver, copper, iron, cobalt, nickel, aluminum, indium, tin, platinum, palladium, titanium, and alloys thereof. The average diameter of the metal nanowires is selected according to actual needs and is not specifically limited. Optionally, the average diameter of the metal nanowires in some embodiments of the present invention is less than 300 nm to provide good transparency and low haze. Further, the average diameter of the metal nanowires is less than 200 nm, and can be selected from 10 nm to 150 nm, and further, can be selected from 10 nm to 100 nm. Similarly, the average length of the metal nanowires is selected according to actual needs and is not specifically limited. Optionally, the average length of the metal nanowires in some embodiments of the present invention is greater than 2 μm to provide good conductivity. Further, the average length of the metal nanowires is greater than 5 μm, and further, can be selected from 10 μm to 100 μm. In some embodiments of the present invention, the method for depositing a metal nanowire dispersion to form the conductive layer 110 can utilize conventional coating formation methods in the art, such as drop coating, spin coating, spray coating, roller coating, dip coating, doctor blade coating, rod coating, printing, screen printing, knife edge coating, slot die coating, etc. After forming the coating, the sparse metal can be dried to remove the liquid at a drying temperature of 45°C to 160°C. After drying, the coating can be washed with ethanol, isopropyl alcohol, or other solvents and further dried to remove excess solids and reduce haze. It should be understood that the conductive layer 110 can also be patterned by selecting a conventional stripping process.The average thickness of the conductive layer 110 is selected based on actual needs and is not specifically limited. Optionally, the average thickness of the conductive layer 110 formed in some embodiments of the present invention is 4 μm or less, further preferably 3 μm or less, and even more preferably 10 to 800 nm. In some embodiments of the present invention, the metal nanowires in the conductive layer 110 overlap to form an interconnected structure or a network structure, and the mass per unit area of ​​the metal nanowires is 0.1 mg / m. 2 Up to 350 mg / m 2 , in order to improve transparency, conductivity and reduce haze, further, 1mg / m 2 Up to 280 mg / m 2 , further, 10mg / m 2 Up to 150 mg / m 2 , all are the qualities before patterning.

[0035] The outer coating 120 can be arranged on the upper side and / or lower side of the conductive layer 110 to provide protection for the conductive layer 110, which can include mechanical, humidity, radiation, heat, oxygen and other protections. It is composed of a composition of polymers and is also called a polymer layer. The outer coating 120 is formed by a dispersion (solution) including a polymer, and the dispersion includes a solvent, and can be formed into an outer coating 120 by adding conventional additives in the art. The solvent and additives of the outer coating 120 and the amount added can refer to the solvent and additives and the amount added for forming the conductive layer 110 as described above, and will not be repeated here. The polymer of the outer coating 120 can be listed as: polyurethane (PU), acrylic resin (PA), acrylic acid (ester)-styrene-acrylonitrile copolymer (ASA), epoxy resin (EP), other polyesters, polyethers, cellulose polymers, polysaccharide polymers, and mixtures thereof. The polymer can be self-crosslinked under heating or irradiation, or can be crosslinked by adding a photoinitiator or other crosslinking agent. The content of the polymer is 0.001wt% to 10wt% based on the mass of the dispersion. Optionally, the content of the polymer is 0.01wt% to 8wt%. The preparation method of the outer coating 120 also refers to the preparation method of the conductive layer 110 described above, and will not be repeated here. The junction between the prepared outer coating 120 and the conductive layer 110 may be entangled or interwoven. The average thickness of the outer coating 120 is selected according to actual needs and is not specifically limited. Optionally, in some embodiments of the present invention, the outer coating 120 can have an average thickness of 10nm to 1.5μm, and further, it can be selected to be 10nm to 500nm.

[0036] The optically transparent adhesive layer 130 can be optionally disposed on the upper and / or lower sides of the conductive layer 110 or the outer coating layer 120. The aforementioned component layers can optionally be sequentially coated or bonded via the optically transparent adhesive layer 130. The optically transparent adhesive layer 130 can be formed by, for example, coating a liquid optically transparent adhesive or adhesive tape. The liquid optically transparent adhesive can include a UV-curable coating composition based on acrylic or polysiloxane chemical components. The average thickness of the optically transparent adhesive layer 130 is selected based on actual needs and is not specifically limited. Optionally, in some embodiments of the present invention, the optically transparent adhesive layer 130 can have an average thickness of 10 nm to 300 μm, and further, can be 10 nm to 100 μm.

[0037] Suitable compositions of the top protective layer 140 can refer to the composition of the substrate 100 described above, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polysulfone ether (PES), polycarbonate (PC), polyetherimide (PEI), polyacrylate (PA), polydimethoxysiloxane (PDMS), polyvinyl alcohol (PVA), copolymers thereof, or mixtures thereof, as well as other suitable optically transparent polymers with high transparency, low haze, and good protective support, can all be used as the material of the top protective layer 140 of the present invention. The thickness of the top protective layer 140 is not particularly limited and can be appropriately selected according to the purpose. In some embodiments of the present invention, the thickness of the top protective layer 140 can be 5 μm to 500 μm, further, 10 μm to 300 μm, and even more preferably 50 μm to 150 μm.

[0038] In some embodiments of the present invention, the light stabilizer adopts a vanadium oxide compound, and the vanadium of the vanadium oxide compound is +2 to +5 valence, and is not +5 valence, including but not limited to at least one of strontium vanadate, lanthanum vanadate, cerium vanadate, calcium vanadate, yttrium vanadate, praseodymium vanadate, neodymium vanadate, vanadium dioxide or vanadium trioxide. Optionally, the vanadium of the vanadium oxide compound is +2 to +4 valence, and further optionally, the vanadium of the vanadium oxide compound is +3 to +4 valence. Taking strontium vanadate as an example, it is a typical perovskite-type transition metal oxide, and its carrier concentration (2.2*10 22 cm -3 ) is higher than ITO(10 21 cm -3 ) of the same magnitude, its resistivity (3.1*10 -7Ω·m) is only one order of magnitude higher than that of metallic silver, and it has excellent metal-like conductivity. At the same time, the optical band gap of strontium vanadate (4.3eV) is larger than that of indium-doped tin oxide (ITO, 3.7eV), and its light transmission window coverage is wider than that of ITO and silver. It has no strong absorption and reflection effects in the Vis (visible light region), almost no intrinsic absorption in the UV (ultraviolet region), and relatively little reflection in the IR (infrared region). This can reduce the absorption of UV by metal nanowires, effectively alleviate the UV-induced plasmon resonance effect and photothermal effect of metal nanowires, and inhibit the diffusion and migration of metal atoms, thereby improving the optical stability of the metal nanowire transparent conductive film. The light stabilizer can be incorporated into at least one of the substrate 100, conductive layer 110, optional overcoat (OC) 120, optional optically clear adhesive layer (OCA) 130, and optional top protective layer 140 in the transparent conductive film multilayer structure as needed. The light stabilizer can be incorporated into a dispersion-based composition, which can be applied to form any component layer of a given transparent conductive film. In some embodiments of the present invention, the light stabilizer is incorporated into the dispersion composition based on the conductive layer 110 and / or the overcoat layer 120 in a predetermined amount; further, in other embodiments of the present invention, the light stabilizer is incorporated into the dispersion (solution) based on the overcoat layer 120 in a predetermined amount; the amount of the light stabilizer added to the dispersion is 0.001 to 3 wt %, optionally, the amount of the light stabilizer added to the dispersion is 0.001 to 1 wt %, further optionally, the amount of the light stabilizer added to the dispersion is 0.005 to 0.08 wt %, and further optionally, the amount of the light stabilizer added to the dispersion is 0.008 to 0.06 wt %. In addition, the light stabilizer can also be independently formed into a solution and applied to any component layer of the transparent conductive film multilayer structure by conventional methods such as dipping, spraying or coating. Optionally, the vanadium oxide compound is a micron or nano material, and the micron or nano material includes at least one of micron or nano particles, micron or nano fibers, micron or nano sheets or micron or nano spheres. Further optionally, the vanadium oxide compound is at least one of micron spheres, micron sheets, nano fibers or nano particles. Further optionally, the average diameter of the micron spheres is 5 to 100 μm, optionally 10 to 50 μm, or optionally 10 to 30 μm; the average length of the nano fibers is 0.5 to 50 μm, optionally 0.5 to 30 μm, and the average diameter of the nano fibers is 10 to 500 nm, or optionally 30 to 300 nm; the sheet length of the micro sheets is 3 to 100 μm, optionally 5 to 50 μm, and the width is 0.5 to 10 μm, or optionally 1 to 5 μm; the average diameter of the nano particles is 5 to 500 nm, optionally 10 to 300 nm, or further optionally 10 to 100 nm.

[0039] Ultraviolet (UV) irradiation was used to evaluate the stability of the transparent conductive film. The UV irradiation used a UVB light source with a wavelength of 313nm. The distance between the film surface and the light source lamp was set to only 5cm. This can achieve close-range high-intensity irradiation, thereby causing strong metal atomic resonance on the surface of the metal nanowires, which has the effect of accelerating aging. The UV light energy density on the sample surface reached 0.5mW / cm 2 , irradiate for 500h or 1000h, compare the photoelectric properties of the transparent conductive film before and after irradiation, including the change rate of square resistance Rs, visible light transmittance Tvis, and haze H, sample at each time point, and detect the values ​​of any three points on the transparent conductive film in parallel, and then take the average value to obtain the photoelectric performance data (square resistance Rs, visible light transmittance Tvis, haze H) of the transparent conductive film after UV irradiation for a certain period of time.

[0040] Among them, the four-probe method is used to test the square resistance Rs of the conductive film to characterize its conductivity. s The unit of measurement is ohms / square (Ω / □ or ohms / sq), tested according to ASTM D991-89 (2020). Different applications and fields have different requirements for the sheet resistance of transparent conductive films. Generally, the sheet resistance of transparent conductive films used in optoelectronic products and devices should not exceed 500Ω / □. For example, the sheet resistance of transparent conductive films used in optoelectronic devices such as OLED and OPV should not exceed 50Ω / □, the sheet resistance of transparent conductive films used in large-size capacitive touch screens should not exceed 100Ω / □, and the sheet resistance of transparent conductive films used in optoelectronic devices such as PDLC smart dimming films should not exceed 500Ω / □.

[0041] Visible light transmittance (Tvis) is tested according to ASTM D1003-21. Currently, mainstream optoelectronic devices and products require transparent conductive films to have a Tvis of at least 80% in the visible light region. OLEDs and capacitive touchscreens require a Tvis of at least 85%. Infrared imaging optoelectronic devices have even higher requirements for transparent conductive films, generally requiring a Tvis of at least 90%.

[0042] Haze H is another important optical performance indicator. Higher haze will cause optoelectronic display products to appear blurry, turbid, and have reduced clarity, affecting practical applications. It is tested according to standards ASTM D1003-21 or JIS K7105-1981.

[0043] The present invention requires that the sheet resistance (Rs) of each example sample after UV irradiation aging should not exceed 40Ω / □, the visible light transmittance (Tvis) should be at least 85%, and the haze (H) should not exceed 8.0%. After 1000 hours of UV irradiation, the sheet resistance (Rs) should not exceed 100Ω / □, the visible light transmittance (Tvis) should not be less than 85%, and the haze (H) should not be higher than 8.0%, indicating that the performance requirements for practical applications are met. The effect of the light stabilizer on the stability of the transparent conductive film was determined by comparing the changes in three key optoelectronic performance parameters (sheet resistance (Rs), visible light transmittance (Tvis), and haze (H)) of the transparent conductive film incorporating the light stabilizer with those of a blank sample.

[0044] The present invention is further described below with reference to specific examples. Unless otherwise specified, the raw materials in the specific examples of the present invention are commercially available or obtained by conventional preparation methods in the art.

[0045] Preparation example:

[0046] Preparation Example 1

[0047] Preparation Example 1: Silver nanowires were prepared, comprising the following steps: 600 mL of ethylene glycol was added to a clean 1-liter stainless steel reactor, and 200 mg of sodium chloride, 200 mg of sodium bromide, and 2.0 g of polyvinylpyrrolidone (PVP, K30) were added sequentially with stirring at 500 rpm. After complete dissolution, 50 mL of ethylene glycol solution containing 1.5 g of silver nitrate was evenly added dropwise for 30 minutes. The reaction mixture was then heated to 180°C and maintained for 1.5 hours. The reaction mixture was cooled to room temperature, and 3 L of deionized water was added to disperse the mixture evenly. The silver nanowires were then selectively precipitated with acetone and collected by centrifugal sedimentation. The resulting pure silver nanowires were dispersed in 80 mL of anhydrous ethanol and stirred evenly to obtain a silver nanowire ethanol dispersion, which was then set aside. The prepared silver nanowires had an average length of 30 μm, an average diameter of 25 nm, and an aspect ratio of 1200.

[0048] Preparation Example 2

[0049] Preparation Example 2 Strontium vanadate (SrVO3, nanofiber) was prepared, comprising the following steps: 2 mmol of NH4VO3 was weighed to prepare 25 mL of a light yellow vanadium source solution; 1 mmol of an acidifying agent H2C2O4 was weighed to add the light yellow vanadium source solution to prepare an orange-red vanadium source solution; 2 mmol of strontium nitrate (Sr(NO3)2, CAS: 10042-76-9) was weighed to prepare 20 mL of a strontium source solution; 0.1 g of sodium dodecyl sulfate (SDS, CAS No.: 151-21-3) was weighed to prepare 5 mL of a 5% vanadium source solution. SDS surfactant solution; the three solutions were mixed to obtain a stable homogeneous solution; the homogeneous solution was then transferred to a hydrothermal reactor with a polytetrafluoroethylene liner with a capacity of 100 mL, kept at 180°C for 12 hours, and cooled to room temperature with the furnace; centrifugal drying was performed to obtain a strontium vanadium oxide SrV2O6 nanofiber precursor with an average length of 10 μm, an average diameter of 50 nm, and an aspect ratio of 200; the precursor was calcined at 800°C in hydrogen in a tubular furnace for 2 hours, and cooled to prepare strontium vanadate nanofibers with an average length of 10 μm, an average diameter of 50 nm, and an aspect ratio of 200.

[0050] Preparation Example 3

[0051] Preparation Example 3 prepares lanthanum vanadate (LaVO3). The difference between Preparation Example 3 and Preparation Example 2 is that an equal amount of lanthanum nitrate (La(NO3)3·6H2O, CAS: 10277-43-7) is used to replace the strontium nitrate (Sr(NO3)2) of Preparation Example 2. The remaining preparation steps are the same as those of Preparation Example 2, and lanthanum vanadate microspheres with an average diameter of 20 μm are prepared.

[0052] Preparation Example 4

[0053] Preparation Example 4 prepares cerium vanadate (CeVO3). The difference between Preparation Example 4 and Preparation Example 2 is that an equal amount of cerium nitrate (Ce(NO3)3·6H2O, CAS:10294-41-4) is used to replace the strontium nitrate (Sr(NO3)2) in Preparation Example 2. The remaining preparation steps are the same as those in Preparation Example 2. Cerium vanadate nanofibers with an average length of 1 μm, an average diameter of 100 nm, and an aspect ratio of 10 are prepared.

[0054] Preparation Example 5

[0055] Preparation Example 5 prepares vanadium dioxide (VO2). The difference between Preparation Example 5 and Preparation Example 2 is that the strontium source solution in Preparation Example 2 is removed, and the remaining preparation steps are the same as Preparation Example 2, and thin flake vanadium dioxide is prepared, the flake length of which is 10 μm, the width of which is 2 μm, and the aspect ratio of which is 5.

[0056] Preparation Example 6

[0057] Preparation Example 6 prepares vanadium trioxide (V2O3). The difference between Preparation Example 6 and Preparation Example 2 is that the strontium source solution in Preparation Example 2 is removed, and the 2 mmol NH4VO3 in the vanadium source solution in Preparation Example 2 is adjusted to 4 mmol NH4VO3. The remaining preparation steps are the same as those in Preparation Example 2. The prepared thin flake vanadium trioxide has a flake length of 20 μm, a width of 1.5 μm, and an aspect ratio of 13.33.

[0058] Preparation Example 7

[0059] Preparation Example 7: Strontium vanadate (SrVO3, nanoparticles) is prepared, comprising the following steps: weighing 2 mmol of NH4VO3 and preparing 25 mL of a vanadium source solution; weighing 2 mmol of strontium nitrate (Sr(NO3)2, CAS:10042-76-9) and preparing 25 mL of a strontium source solution; weighing 0.6 mL of dilute nitric acid and adding the strontium source solution; mixing the above solutions to obtain a stable homogeneous solution; adding 2 mL of a 0.2 M KOH solution to the above homogeneous solution to obtain a precipitate; centrifuging and drying the mixed solution after the precipitation reaction to obtain a strontium vanadium oxide precursor; calcining the precursor in a tubular furnace at 800°C for 2 h, and cooling to prepare strontium vanadate nanoparticles, the average particle size of the strontium vanadate nanoparticles being 50 nm.

[0060] Example 1 (Silver Nanowire Transparent Conductive Film: Blank Control Sample, Comparative Example)

[0061] The present invention provides a method for preparing a silver nanowire transparent conductive film, comprising the following steps:

[0062] S1. Preparation of silver nanowire dispersion: The silver nanowire ethanol dispersion prepared in Preparation Example 1 was ultrasonically dispersed for no more than 10 min, with an input power of 100 W and a frequency of 40 kHz to prepare a silver nanowire ethanol dispersion with a mass concentration of 1.0 wt%.

[0063] S2. Preparation of a polymer dispersion: A waterborne polyurethane resin (WPU, 35 wt %, Anhui Anda Huatai New Materials) was dispersed and dissolved in ethanol to obtain a waterborne polyurethane resin ethanol dispersion with a mass concentration of 5.0 wt %.

[0064] S3. Preparation of coating modifier solution: The coating modifier includes a viscosity modifier hydroxypropyl methylcellulose (HPMC, CAS No.: 9004-65-3, viscosity 4000 cps, Aladdin) and a surface tension modifier FS-31 fluorocarbon surfactant (25 wt%, DuPont, USA). The two modifiers are dispersed and dissolved in ethanol to obtain coating modifier solutions A and B, respectively. The mass concentration of the viscosity modifier of coating modifier solution A is: HPMC 0.5 wt%, and the mass concentration of the surface tension modifier of coating modifier solution B is: FS-31 2.5 wt%.

[0065] S4. Prepare a silver nanowire coating solution: The silver nanowire ethanol dispersion in step S1 and the coating regulator solution in step S3 are mixed in a certain proportion, and then uniformly dispersed by ultrasonication. The ultrasonic dispersion time does not exceed 10 min, the input power does not exceed 300 W, and the frequency is 40 kHz to prepare a silver nanowire coating solution. The mass concentrations of silver nanowires, HPMC and FS-31 in the silver nanowire coating solution are 0.18 wt%, 0.3 wt% and 0.05 wt%, respectively.

[0066] S5. Preparation of a polymer coating liquid: The aqueous polyurethane resin ethanol dispersion prepared in step S2 and the coating regulator solution prepared in step S3 are mixed in a certain proportion, and then uniformly dispersed by ultrasonication. The ultrasonic dispersion time does not exceed 10 min, the input power does not exceed 300 W, and the frequency is 40 kHz to prepare a polymer coating liquid. The mass concentrations of WPU and FS-31 in the polymer coating liquid are 0.8 wt% and 0.03 wt%, respectively.

[0067] S6. Primary coating: A PET substrate (125 μm thick, 5 cm long, 5 cm wide, Toray, Japan) was used as a flexible substrate. After cleaning and drying, it was placed on a benchtop homogenizer and fixed by adsorption using a vacuum pump. 1 mL of the silver nanowire coating solution prepared in step S4 was accurately drawn with a micropipette and evenly drop-coated on the PET substrate at a speed of 400 rpm for 5 seconds. After coating, the substrate was placed in an oven at 110°C and dried for 5 minutes to prepare a silver nanowire conductive layer on the PET substrate.

[0068] S7. Secondary coating: The same coating method as in step S6 is used on the silver nanowire conductive layer prepared in step S6. 1 mL of the polymer coating liquid prepared in step S5 is accurately aspirated again with a micropipette, and the polymer coating liquid prepared in step S5 is coated on the silver nanowire conductive layer. A polymer layer (outer coating) is prepared on the silver nanowire conductive layer. The substrate / conductive layer / polymer layer constitutes a multilayer stacked structure of a transparent conductive film, thereby preparing a silver nanowire transparent conductive film.

[0069] The silver nanowire transparent conductive film prepared in Example 1 had a square resistance (Rs) of 34.00 Ω / □, a haze (H) of 3.39%, and a visible light transmittance (Tvis) of 87.73%. After 1000 hours of UV irradiation, the square resistance (Rs) increased by 579.51% to 231.03 Ω / □, the haze (H) increased by 2.95% to 3.49%, and the visible light transmittance (Tvis) decreased by 1.47% to 86.44%.

[0070] Example 2 (Adding Light Stabilizer Strontium Vanadate to the Conductive Layer)

[0071] Example 2 differs from Example 1 in that, in step S1, a silver nanowire dispersion is prepared: the silver nanowire ethanol dispersion prepared in Preparation Example 1 and the strontium vanadate nanofibers prepared in Preparation Example 2 are ultrasonically dispersed to form a strontium vanadate / silver nanowire ethanol dispersion. In step S4, a silver nanowire coating solution is prepared, wherein the mass concentrations of silver nanowires, strontium vanadate nanofibers, HPMC, and FS-31 in the silver nanowire coating solution are 0.18 wt%, 0.01 wt%, 0.3 wt%, and 0.05 wt%, respectively. The remaining preparation steps are the same as in Example 1, and a strontium vanadate / silver nanowire transparent conductive film is prepared.

[0072] The strontium vanadate / silver nanowire transparent conductive film of Example 2 showed an Rs of 36.33 Ω / □, a haze H of 3.33%, and a visible light transmittance Tvis of 88.05%. Compared with a silver nanowire transparent conductive film based on the same batch of silver nanowires without the addition of strontium vanadate, the silver nanowire transparent conductive film without the addition of strontium vanadate had a square resistance Rs of 34.0 Ω / □, a haze H of 3.39%, and a visible light transmittance Tvis of 87.73%. This corresponds to an increase in square resistance Rs of 6.85%, a decrease in haze H of 1.77%, and an increase in visible light transmittance of 0.36%. The addition of strontium vanadate nanofibers to the conductive layer improves the transmittance of the transparent conductive film and reduces haze. However, the direct addition of strontium vanadate to the silver nanowire conductive layer slightly increases its resistance. However, its square resistance is only 36.33 Ω / □, still far below the required square resistance for practical applications.

[0073] Example 3 (light stabilizer strontium vanadate is added to both the conductive layer and the polymer layer)

[0074] The difference between Example 3 and Example 1 is that the silver nanowire ethanol dispersion prepared in Preparation Example 1 and the strontium vanadate nanofibers prepared in Preparation Example 2 are ultrasonically dispersed to form a strontium vanadate / silver nanowire ethanol dispersion; S2. Preparing a polymer dispersion: ultrasonically dispersing an aqueous polyurethane resin and the strontium vanadate nanofibers prepared in Preparation Example 2 in ethanol to obtain a strontium vanadate / aqueous polyurethane resin ethanol dispersion; in step S4., a silver nanowire coating solution is prepared, and the mass concentrations of silver nanowires, strontium vanadate nanofibers, HPMC and FS-31 in the silver nanowire coating solution are 0.18wt%, 0.01wt%, 0.3wt% and 0.05wt%, respectively; in step S5., a polymer coating solution is prepared, and the mass concentrations of WPU, FS-31 and strontium vanadate nanofibers in the polymer coating solution are 0.8wt%, 0.03wt% and 0.01wt%, respectively. The remaining preparation steps were the same as those in Example 1 to prepare a strontium vanadate / silver nanowire transparent conductive film.

[0075] The strontium vanadate / silver nanowire composite transparent conductive film of Example 3 was measured to have an Rs of 35.0Ω / □, a haze H of 3.44%, and a visible light transmittance Tvis of 87.83%; compared with the silver nanowire transparent conductive film based on the same batch of silver nanowires and without the addition of strontium vanadate, the silver nanowire transparent conductive film without the addition of strontium vanadate had a square resistance Rs of 34.0Ω / □, a haze H of 3.39%, and a visible light transmittance Tvis of 87.73%. The square resistance Rs increased by 2.94%, the haze H increased by 1.47%, and the visible light transmittance increased by 0.11%.

[0076] Example 4 (Adding a light stabilizer, strontium vanadate, to the polymer layer)

[0077] Example 4 differs from Example 1 in that, in step S2., a polymer dispersion is prepared: an aqueous polyurethane resin and the strontium vanadate nanofibers prepared in Preparation Example 2 are ultrasonically dispersed in ethanol to obtain a strontium vanadate / aqueous polyurethane resin ethanol dispersion. In step S5., a polymer coating solution is prepared, wherein the mass concentrations of WPU, FS-31, and strontium vanadate nanofibers in the polymer coating solution are 0.8 wt%, 0.03 wt%, and 0.01 wt%, respectively. The remaining preparation steps are the same as in Example 1, resulting in a strontium vanadate / silver nanowire transparent conductive film.

[0078] The strontium vanadate / silver nanowire composite transparent conductive film of Example 4 was measured to have an Rs of 33.62Ω / □, a haze H of 3.68%, and a visible light transmittance Tvis of 85.13%; compared with the silver nanowire transparent conductive film based on the same batch of silver nanowires and without the addition of strontium vanadate, the silver nanowire transparent conductive film without the addition of strontium vanadate had a square resistance Rs of 35.96Ω / □, a haze H of 4.04%, and a visible light transmittance Tvis of 85.73%. The square resistance Rs was reduced by 6.51%, the haze H was reduced by 8.91%, and the visible light transmittance Tvis was reduced by 0.70%. After 1000h of UV irradiation, the square resistance Rs of the silver nanowire transparent conductive film of Example 4 was 85.09Ω / □, which increased by 153.09%, the haze H was 4.20%, which increased by 14.13%, and the transmittance Tvis in the visible light region was 85.54%, which increased by 0.48%.

[0079] refer to Figure 2 , Figure 2 The comparison of the photoelectric performance of the silver nanowire transparent conductive film with strontium vanadate added to the polymer layer in Example 4 and the silver nanowire transparent conductive film without strontium vanadate added in Example 1 after ultraviolet irradiation for 1000 hours is shown. Figure 2 It can be seen that within the first 500 hours, the two trends are consistent, with little change in the optoelectronic performance data. However, as the irradiation time increases, the transparent conductive film in Example 4 with strontium vanadate added to the polymer layer shows only a slow increase in square resistance to 85.09 Ω / □ after 1000 hours of UV irradiation, a slight increase in transmittance to 85.54%, and a relatively small change in haze value to 4.20%. These three key parameters remain within the required range for practical applications. In contrast, the transparent conductive film in Example 1 without strontium vanadate added to the polymer layer shows a resistance of 231.03 Ω / □ after 1000 hours of irradiation, an increase of 579.51%, a rate of change much higher than that of the transparent conductive film with strontium vanadate added. This shows that strontium vanadate significantly improves the optoelectronic stability of the transparent conductive film.

[0080] Table 1. Effects of different addition positions of strontium vanadate on the photoelectric properties of transparent conductive films

[0081] <![CDATA[R / R0]]> <![CDATA[H / H0]]> <![CDATA[T / T0]]> Example 2 (conductive layer) 1.069 0.982 1.004 Example 3 (Conductive layer and polymeric layer) 1.029 1.015 1.001 Example 4 (polymeric layer) 0.935 0.911 0.993

[0082] Referring to Table 1, Table 1 shows the effects of different addition positions of strontium vanadate on the photoelectric properties of strontium vanadate / silver nanowire transparent conductive films in Examples 2-4. It can be seen from Table 1 that adding strontium vanadate to different positions of the conductive film (respectively, the conductive layer, both at the same time, or the polymer layer) has slightly different effects on the square resistance Rs of the conductive film: in Example 2, when strontium vanadate is added to the conductive layer, the square resistance increases slightly; in Example 3, when strontium vanadate is added to the conductive layer and the polymer layer, the square resistance increases slightly; in Example 4, when strontium vanadate is added to the polymer layer, the square resistance decreases slightly, which is beneficial to improving the conductive performance. The effects on the haze H and transmittance T of the transparent conductive film are small and can be ignored. Taking all factors into consideration, the subsequent examples all adopt the method of adding strontium vanadate or other light stabilizers to the polymer layer.

[0083] Example 5 (Different types of vanadium oxide compounds: lanthanum vanadate)

[0084] The difference between Example 5 and Example 4 is that the strontium vanadate in Example 4 is replaced by the lanthanum vanadate prepared in Preparation Example 3 of equal mass, and the remaining preparation steps are the same as in Example 4 to prepare a lanthanum vanadate / silver nanowire transparent conductive film.

[0085] The lanthanum vanadate / silver nanowire transparent conductive film of Example 5 showed a sheet resistance (Rs) of 26.92 Ω / □, a haze (H) of 3.34%, and a visible light transmittance (Tvis) of 85.42%. After 1000 hours of UV irradiation, the sheet resistance (Rs) increased by 108.95% to 56.25 Ω / □, the haze (H) increased by 17.66% to 3.93%, and the visible light transmittance (Tvis) increased by 1.56% to 86.75%.

[0086] Example 6 (Different Types of Vanadium Oxycompounds: Cerium Vanadate)

[0087] The difference between Example 6 and Example 4 is that the cerium vanadate prepared in Preparation Example 4 of equal mass is used to replace the strontium vanadate in Example 4, and the remaining preparation steps are the same as in Example 4 to prepare a cerium vanadate / silver nanowire transparent conductive film.

[0088] The cerium vanadate / silver nanowire transparent conductive film of Example 6 showed a square resistance (Rs) of 31.88 Ω / □, a haze (H) of 2.86%, and a visible light transmittance (Tvis) of 86.80%. After 1000 hours of UV irradiation, the square resistance (Rs) increased by 165.24% to 84.56 Ω / □, the haze (H) increased by 22.03% to 3.49%, and the visible light transmittance (Tvis) increased by 0.92% to 87.60%.

[0089] Example 7 (Different Types of Vanadium Oxides: Vanadium Dioxide)

[0090] The difference between Example 7 and Example 4 is that the strontium vanadate in Example 4 is replaced by an equal mass of vanadium dioxide prepared in Preparation Example 5, and the remaining preparation steps are the same as in Example 4 to prepare a vanadium dioxide / silver nanowire transparent conductive film.

[0091] The vanadium dioxide / silver nanowire transparent conductive film of Example 7 showed a square resistance (Rs) of 29.29 Ω / □, a haze (H) of 3.31%, and a visible light transmittance (Tvis) of 85.56%. After 1000 hours of UV irradiation, the square resistance (Rs) increased by 113.86% to 62.64 Ω / □, the haze (H) increased by 18.73% to 3.93%, and the visible light transmittance (Tvis) increased by 1.27% to 86.65%.

[0092] Example 8 (Different types of vanadium oxide compounds: vanadium trioxide)

[0093] The difference between Example 8 and Example 4 is that the strontium vanadate in Example 4 is replaced by vanadium trioxide prepared in Preparation Example 6 with an equal mass, and the remaining preparation steps are the same as in Example 4 to prepare a vanadium trioxide / silver nanowire transparent conductive film.

[0094] The vanadium trioxide / silver nanowire transparent conductive film of Example 8 showed a square resistance (Rs) of 33.31 Ω / □, a haze (H) of 3.25%, and a visible light transmittance (Tvis) of 85.55%. After 1000 hours of UV irradiation, the square resistance (Rs) increased by 130.11% to 76.65 Ω / □, the haze (H) increased by 22.15% to 3.97%, and the visible light transmittance (Tvis) decreased by 0.19% to 85.39%.

[0095] refer to Figure 3 , Figure 3 The photoelectric properties (square resistance Rs, visible light transmittance Tvis, haze H) of the transparent conductive films of Example 1 without adding stabilizer and Examples 4 to 8 with adding different types of vanadium oxide compounds / silver nanowires after UV irradiation for 1000h are shown. Figure 3 It can be seen that different types of vanadium oxide compounds, including +3-valent V2O3, lanthanum vanadate (LaVO3) and cerium vanadate (CeVO3), as well as +4-valent VO2 and strontium vanadate (SrVO3), are added to the polymer layer of the transparent conductive film as light stabilizers. After 1000 hours of ultraviolet irradiation, they all show good photoelectric properties. The square resistance Rs, visible light transmittance Tvis and haze H of the conductive film all change little and are within the allowable range for practical applications. In particular, the square resistance change has better stability than the blank sample in Example 1.

[0096] Example 9 (Different Forms of Strontium Vanadate: Nanoparticles)

[0097] The difference between Example 9 and Example 4 is that the strontium vanadate nanoparticles prepared in Preparation Example 7 of equal mass are used to replace the strontium vanadate nanofibers in Example 4, and the remaining preparation steps are the same as in Example 4 to prepare a strontium vanadate / silver nanowire transparent conductive film.

[0098] The strontium vanadate / silver nanowire composite transparent conductive film of Example 9 showed a square resistance (Rs) of 32.20 Ω / □, a haze (H) of 2.98%, and a visible light transmittance (Tvis) of 85.20%. After 1000 hours of UV irradiation, the square resistance (Rs) increased by 70.99% to 55.06 Ω / □, the haze (H) increased by 13.76% to 3.39%, and the visible light transmittance (Tvis) increased by 0.55% to 85.67%.

[0099] refer to Figure 4 , Figure 4 The photoelectric properties (square resistance Rs, visible light transmittance Tvis, haze H) of the composite transparent conductive film of Example 1 without adding stabilizer and Example 4 and Example 9 with adding different forms of strontium vanadate nanomaterials / silver nanowires after ultraviolet irradiation for 1000h are shown. Figure 4 It can be seen that different forms of strontium vanadate all improve the photoelectric performance and stability of the transparent conductive film compared to a blank sample without the addition of a light stabilizer. Furthermore, the photoelectric performance and stability of the transparent conductive film in Example 9, when strontium vanadate nanoparticles are added, are superior to those of the conductive film in Example 4, which contains strontium vanadate nanofibers, after 1000 hours of UV irradiation. The change in square resistance (Rs) is smaller, indicating better stability.

[0100] Example 10 (Strontium vanadate nanofibers with different contents)

[0101] The difference between Example 10 and Example 4 is that 0.05 wt % strontium vanadate is used to replace 0.01 wt % strontium vanadate in Example 4, and the remaining preparation steps are the same as Example 4 to prepare a strontium vanadate / silver nanowire transparent conductive film.

[0102] The strontium vanadate / silver nanowire transparent conductive film of Example 10 was measured to have a square resistance Rs of 25.50 Ω / □, a haze H of 7.28%, and a visible light transmittance Tvis of 86.45%. Compared with the silver nanowire transparent conductive film without the addition of strontium vanadate, its square resistance Rs was reduced by 25%, the haze H was increased by 114.81%, and the visible light transmittance Tvis was reduced by 1.46%.

[0103] After UV irradiation for 500h, its square resistance Rs was 54.25Ω / □, increased by 112.75%, the haze H was 7.52%, increased by 3.29%, and the transmittance Tvis in the visible light region was 85.34%, decreased by 1.29%.

[0104] Example 11 (Strontium vanadate nanofibers with different contents)

[0105] The difference between Example 11 and Example 4 is that 0.025 wt % strontium vanadate is used to replace 0.01 wt % strontium vanadate in Example 4, and the remaining preparation steps are the same as Example 4 to prepare a strontium vanadate / silver nanowire transparent conductive film.

[0106] The strontium vanadate / silver nanowire transparent conductive film of Example 11 was measured to have a square resistance Rs of 25.75Ω / □, a haze H of 4.86%, and a visible light transmittance Tvis of 86.43%; compared with the silver nanowire transparent conductive film without adding strontium vanadate, its square resistance Rs was reduced by 24.26%, the haze H was increased by 43.36%, and the visible light transmittance Tvis was reduced by 1.48%.

[0107] After UV irradiation for 500h, its square resistance Rs was 37.50Ω / □, which increased by 45.63%, its haze H was 5.40%, which increased by 11.01%, and its transmittance in the visible light region Tvis was 85.52%, which decreased by 1.05%.

[0108] refer to Figure 5 , Figure 5 The photoelectric properties (square resistance Rs, visible light transmittance Tvis, haze H) of the conductive film after 500 hours of ultraviolet irradiation of the samples without strontium vanadate in Example 1 and with different addition amounts in Examples 4, 10, and 11 are shown; Figure 5 It can be seen that: by comparing the photoelectric performance data of samples with different strontium vanadate additions and blank samples after 500 hours of ultraviolet irradiation, the photoelectric performance and stability of the transparent conductive film with added strontium vanadate are better than those of the blank control sample without added strontium vanadate. After adding strontium vanadate, the change rate of the square resistance Rs, visible light transmittance Tvis and haze H of the conductive film after ultraviolet irradiation is small, all within the allowable range of practical application, and the stability of the addition of 0.01wt% and 0.025wt% is significantly better than that of the addition of 0.05wt%.

[0109] Comparative Example 1 (+5-valent vanadium: NaVO3)

[0110] The difference between Comparative Example 1 and Example 4 is that an equal mass of sodium metavanadate (NaVO3·2H2O, CAS: 13718-26-8) with a valence of +5 is used to replace the strontium vanadate in Example 4, and the remaining preparation steps are the same as those in Example 4 to prepare a NaVO3 / silver nanowire transparent conductive film.

[0111] The NaVO3 / silver nanowire composite transparent conductive film of Comparative Example 1 had a sheet resistance (Rs) of 28.54 Ω / □, a haze (H) of 3.21%, and a visible light transmittance (Tvis) of 85.49%. After 1000 hours of UV irradiation, the sheet resistance (Rs) increased to infinity and could not be measured. The haze (H) increased by 14.02% to 3.66%, and the visible light transmittance (Tvis) decreased by 3.58% to 82.43%. After 750 hours of irradiation, the Rs reached 657.20 Ω / □, an increase of 2202.73%.

[0112] Comparative Example 2 (Vanadium +5: SrV2O6)

[0113] The difference between Comparative Example 2 and Example 4 is that an equal mass of +5-valent SrV2O6 (see the SrV2O6 nanofiber precursor in Preparation Example 2, with an average length of 10 μm, an average diameter of 50 nm, and an aspect ratio of 200) is used to replace the strontium vanadate in Example 4, and the remaining preparation steps are the same as in Example 4 to prepare a SrV2O6 / silver nanowire transparent conductive film.

[0114] The SrV2O6 / silver nanowire transparent conductive film of Comparative Example 2 was measured to have a square resistance Rs of 33.93Ω / □, a haze H of 3.21%, and a visible light transmittance Tvis of 85.42%; after 1000h of UV irradiation, its square resistance Rs was 113.52Ω / □, an increase of 234.57%, the haze H was 3.87%, an increase of 20.56%, and the visible light transmittance Tvis was 86.48%, an increase of 1.24%.

[0115] refer to Figure 6 , Figure 6 The figure shows the comparison of the photoelectric performance (square resistance Rs, visible light transmittance Tvis, haze H) of the transparent conductive film after UV irradiation for 1000h, which is obtained by adding strontium vanadate in Example 4, adding +5-valent vanadium oxide (NaVO3 and SrV2O6) in Comparative Examples 1 and 2, and the blank sample of Example 1. Figure 6 It can be seen that the two +5-valent vanadium oxide compounds (NaVO3 and SrV2O6) of Comparative Examples 1 and 2 are added to the conductive film as light stabilizers. After 1000 hours of ultraviolet irradiation, compared with the samples containing strontium vanadate and blank samples, their visible light transmittance Tvis and haze H are less affected, but their impact on the square resistance Rs is greater, and even worsens their photoelectric performance. The square resistance Rs value is much higher than the range specified for practical applications, which will cause the transparent conductive film or the corresponding electronic device to malfunction. This further highlights the improvement of the photoelectric performance and stability of the conductive film by strontium vanadate as a light stabilizer.

[0116] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A transparent conductive film comprising a base layer, a conductive layer and an overcoat layer, wherein the conductive layer comprises metal nanowires, characterized in that: The transparent conductive film further includes a light stabilizer, the light stabilizer includes a vanadium oxide compound, the vanadium in the vanadium oxide compound has a valence of +2 to +5, but not +5, and the light stabilizer is contained in at least one of the base layer, the conductive layer, and the overcoat layer; The outer covering is composed of a composition including a polymer; The sheet resistance of the transparent conductive film does not exceed 40 ohms / square, the visible light transmittance is at least 85%, and the haze value does not exceed 8%. After 1000 hours of ultraviolet irradiation, the sheet resistance of the transparent conductive film does not exceed 100 ohms / square, the visible light transmittance is at least 85%, and the haze value does not exceed 8%.

2. The transparent conductive film according to claim 1, wherein The metal nanowires include at least one of gold, silver, copper, iron, cobalt, nickel, aluminum, indium, tin, platinum, palladium or titanium nanowires; And / or, the metal nanowires include composite metal nanowires composed of at least two metals selected from the group consisting of gold, silver, copper, iron, cobalt, nickel, aluminum, indium, tin, platinum, palladium or titanium.

3. The transparent conductive film according to claim 1, wherein The vanadium oxide compound includes at least one of strontium vanadate, lanthanum vanadate, cerium vanadate, calcium vanadate, yttrium vanadate, praseodymium vanadate, neodymium vanadate, vanadium dioxide or vanadium trioxide.

4. The transparent conductive film according to claim 1, wherein The transparent conductive film further includes an optically transparent adhesive layer and / or a top protective layer, and the light stabilizer is contained in at least one of the base layer, the conductive layer, the overcoat layer, the optically transparent adhesive layer, or the top protective layer.

5. The transparent conductive film according to any one of claims 1 to 4, wherein The outer covering layer is composed of a composition including a polymer; and the light stabilizer is contained in at least one of the conductive layer and the outer covering layer.

6. The transparent conductive film according to claim 5, wherein The conductive layer is prepared from a solution comprising the metal nanowires and the light stabilizer, wherein the content of the light stabilizer is 0.001 wt % to 3 wt % of the solution; And / or, the outer coating layer is prepared from a solution comprising a polymer and the light stabilizer, and the content of the light stabilizer is 0.001 wt % to 3 wt % of the solution.

7. The transparent conductive film according to any one of claims 1 to 4, wherein The vanadium oxide compound is a micron or nanometer material, and the micron or nanometer material includes at least one of micron or nanometer particles, micron or nanometer fibers, and micron or nanometer sheets.

8. The transparent conductive film according to any one of claims 1 to 4, wherein The vanadium oxide compound is a micron or nanometer material, and the micron or nanometer material includes micron or nanometer spheres.

9. The transparent conductive film according to any one of claims 1 to 4, wherein The metal nanowires include silver nanowires.

10. An electronic device, characterized in that: The electronic device comprises the transparent conductive film according to any one of claims 1 to 9.

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