A low-resistance transparent conductive film and preparation method thereof

Abstract

The present invention discloses a low-resistance transparent conductive film and a preparation method thereof, and relates to the technical field of ITO thin film materials. The preparation method comprises the following steps: S1: forming an ITO film on the surface of a substrate by magnetron sputtering at room temperature; S2: subjecting the ITO film layer to a gradient freezing treatment, and then restoring it to room temperature to obtain a first ITO film; S3: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic coordinated treatment to obtain a second ITO film; S4: subjecting the second ITO film to alternating cyclic treatments in accordance with the S2 step and the S3 step in sequence to obtain the low-resistance transparent conductive film. In view of the existing ITO film preparation process, the present invention introduces a gradient freezing process and a microwave-ultrasonic coordinated treatment process to perform a joint modification treatment on the ITO film, thereby realizing the preparation of an ITO film with low resistance and high uniformity at room temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive film materials, and in particular to a low-resistance transparent conductive film and a preparation method thereof. Background Art

[0002] In the field of TCO (Transparent Conductive Oxides) thin film material technology, transparent conductive films are widely used in various optoelectronic devices due to their unique optoelectronic properties. Common TCO films are mainly divided into indium tin oxide (ITO) films, aluminum-doped zinc oxide (AZO) films, fluorine-doped tin oxide (FTO) films, antimony-doped tin oxide (ATO) films, gallium-doped zinc oxide (GZO) films, zinc oxide (ZnO) films doped with other elements, titanium oxide (TiO2)-based films, etc. These film materials have their own characteristics, but among many TCO films, ITO films stand out due to their superior optoelectronic properties. They have the characteristics of high transmittance in the visible light band, high conductivity, absorption in the ultraviolet band, and high reflection in the infrared band. Therefore, they are widely used in electronic devices such as liquid crystal displays, solar cells, touch screens, and as a good electromagnetic shielding material.

[0003] There are many methods for preparing ITO thin films, which can be mainly divided into two categories: physical methods and chemical methods. Physical methods mainly include magnetron sputtering, electron beam evaporation, pulsed laser deposition, etc. These methods can produce high-quality ITO films, but often require high deposition temperatures or subsequent heat treatment processes. For example, magnetron sputtering is a commonly used physical deposition method that can be carried out at a lower pressure, has a fast deposition rate, and can produce dense and uniform films. However, although the preparation process of ITO thin films is relatively mature, there are still some defects and problems. Among them, one of the most important problems is the need for high-temperature treatment. High-temperature treatment not only increases the preparation cost, but also limits the range of choices for substrate materials, especially for some substrate materials that are not resistant to high temperatures, such as plastics, etc., traditional high-temperature preparation processes are not applicable. On the other hand, large-size ITO films prepared at room temperature often have problems such as high resistivity and difficulty in ensuring uniformity. This is because as the size of the film increases, it becomes increasingly difficult to maintain the uniformity of its resistance and transmittance, thereby limiting the further widespread application of ITO films. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a low-resistance transparent conductive film and a preparation method thereof.

[0005] In a first aspect, the present invention provides a method for preparing a low-resistance transparent conductive film, the preparation method comprising the following steps:

[0006] S1: forming an ITO thin film on the substrate surface by magnetron sputtering at room temperature;

[0007] S2: subjecting the ITO film layer to a gradient freezing treatment, and then restoring the layer to room temperature to obtain a first ITO film;

[0008] S3: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic coordinated treatment to obtain a second ITO film;

[0009] S4: treating the second ITO film in alternating cycles according to the steps S2 and S3 to obtain the low-resistance transparent conductive film;

[0010] The working condition parameters of the microwave-ultrasonic coordinated treatment include: microwave power of 650-800W, ultrasonic power of 80-150W, and time of 30-60 seconds.

[0011] Furthermore, the microwave power is 720W, and the ultrasonic power is 115W.

[0012] Furthermore, the low-resistance transparent conductive film is a single-layer ITO film not doped with other elements, and the other elements are elements other than In, Sn and O.

[0013] Furthermore, the gradient freezing treatment step includes the following process:

[0014] The first stage: cool down from room temperature to -40~-30℃ at a cooling rate of 5℃ / min and keep it for 30~60 minutes;

[0015] The second stage: continue cooling to -60~-50℃ at a cooling rate of 1℃ / min and maintain for 60~90 minutes.

[0016] Further, the substrate includes a substrate having a size of 6 inches.

[0017] Furthermore, the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the ITO material with a weight ratio of tin oxide to indium oxide of 10:90 is used as the target material, the distance between the target material and the substrate is 50~60mm, the magnetron sputtering power is 30~60W, the magnetron sputtering gas is composed of oxygen with a flow rate of 1~5sccm and argon with a flow rate of 110~130sccm, and the pressure of the magnetron sputtering gas is 0.2~0.5Pa.

[0018] Furthermore, the thickness of the ITO film is 95-110 nm.

[0019] Furthermore, the alternating cycle treatment is performed 4 to 6 times.

[0020] In a second aspect, based on the same inventive concept, the present invention provides a low-resistance transparent conductive film, wherein the low-resistance transparent conductive film is prepared by the method for preparing the low-resistance transparent conductive film described in any one of the first aspects.

[0021] Furthermore, the property parameters of the low-resistance transparent conductive film include: an average square resistance value of less than 40Ω / □, and a square resistance uniformity of less than 10%.

[0022] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0023] The embodiment of the present invention provides a low-resistance transparent conductive film and a preparation method thereof. For the existing ITO film preparation process, the present invention introduces a gradient freezing process and a microwave-ultrasonic coordinated processing process to jointly modify the ITO film. By utilizing gradient freezing, the penetrating and heating effects of microwaves and the cavitation effect of ultrasound, the microstructures such as the grain size, distribution and orientation inside the film can be adjusted, the structural defects in the ITO film can be repaired, and the stress distribution inside the film can be balanced, thereby improving its electrical and optical properties, and successfully realizing the preparation of large-size ITO films with low resistance and high uniformity at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 A schematic flow chart of a method for preparing a low-resistance transparent conductive film provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution 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 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 are within the scope of protection of the present invention.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0029] In a first aspect, the present invention provides a method for preparing a low-resistance transparent conductive film, such as Figure 1 As shown, the preparation method comprises the following steps:

[0030] S1: forming an ITO thin film on the substrate surface by magnetron sputtering at room temperature;

[0031] S2: subjecting the ITO film layer to a gradient freezing treatment, and then restoring the layer to room temperature to obtain a first ITO film;

[0032] S3: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic coordinated treatment to obtain a second ITO film;

[0033] S4: treating the second ITO film in alternating cycles according to the steps S2 and S3 to obtain the low-resistance transparent conductive film;

[0034] The working condition parameters of the microwave-ultrasonic coordinated treatment include: microwave power of 650-800W, ultrasonic power of 80-150W, and time of 30-60 seconds.

[0035] The embodiment of the present invention provides a method for preparing a low-resistance transparent conductive film. For the existing ITO film preparation process, the present invention introduces a gradient freezing process and a microwave-ultrasonic coordinated processing process to jointly modify the ITO film. By utilizing gradient freezing, the penetrating and heating effects of microwaves and the cavitation effect of ultrasound, the microstructures such as the grain size, distribution and orientation inside the film can be adjusted, the structural defects in the ITO film can be repaired, and the stress distribution inside the film can be balanced, thereby improving its electrical and optical properties, and successfully realizing the preparation of large-size ITO films with low resistance and high uniformity at room temperature.

[0036] The microwave-ultrasonic composite field in the present invention refers to a physical composite field formed by applying microwaves and ultrasonic waves at the same time, and its realization can rely on the XO-SM series ultrasonic-microwave combined reaction systems widely sold on the market, as well as various ultrasonic-microwave reactors, microwave-ultrasonic combined reactors and other existing microwave ultrasonic reaction equipment. In specific operations, the ITO film formed on the surface of the substrate by magnetron sputtering is packaged in a vacuum sealed bag and then placed flat in the cavity of the microwave ultrasonic reaction equipment, and an appropriate amount of deionized water is injected into the cavity to ensure that the ITO film is below the water surface, and the microwave ultrasonic reaction equipment is turned on to perform microwave-ultrasonic coordinated processing according to the preset microwave power and ultrasonic power.

[0037] In some specific embodiments, the microwave power is 720W, and the ultrasonic power is 115W.

[0038] In some specific embodiments, the low-resistance transparent conductive film is a single-layer ITO film not doped with other elements, and the other elements are elements other than In, Sn and O.

[0039] In some specific embodiments, the gradient freezing step comprises the following process:

[0040] The first stage: cool down from room temperature to -40~-30℃ at a cooling rate of 5℃ / min and keep it for 30~60 minutes;

[0041] The second stage: continue cooling to -60~-50℃ at a cooling rate of 1℃ / min and maintain for 60~90 minutes.

[0042] In some specific embodiments, the substrate comprises a glass substrate having a size of 6 inches, such as soda-lime glass.

[0043] In some specific embodiments, the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the ITO material with a weight ratio of tin oxide to indium oxide of 10:90 is used as the target material, the distance between the target material and the substrate is 50~60mm, the magnetron sputtering power is 30~60W, the magnetron sputtering gas is composed of oxygen with a flow rate of 1~5sccm and argon with a flow rate of 110~130sccm, and the pressure of the magnetron sputtering gas is 0.2~0.5Pa.

[0044] In some specific embodiments, the thickness of the ITO film is 95-110 nm.

[0045] In some specific embodiments, the alternating cycle treatment is performed 4 to 6 times.

[0046] In a second aspect, based on the same inventive concept, the present invention provides a low-resistance transparent conductive film, wherein the low-resistance transparent conductive film is prepared by the method for preparing the low-resistance transparent conductive film described in any one of the first aspects.

[0047] In some specific embodiments, the property parameters of the low-resistance transparent conductive film include: an average square resistance value of less than 40Ω / □, and a square resistance uniformity of less than 10%.

[0048] It should be noted that the components and raw materials involved in the low-resistance transparent conductive film and the preparation method thereof provided in the embodiments of the present invention, unless otherwise specified or specifically described, can be directly commercially available products or homemade using existing public preparation methods; at the same time, the steps and parameters involved, unless otherwise specified or specifically described, can be carried out according to the ITO film preparation process steps and parameters disclosed in the prior art or directly using existing equipment according to the instruction manual, and the present invention document will not repeat them one by one.

[0049] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed. Example 1

[0050] This example provides a low-resistance transparent conductive film, and the preparation method of the low-resistance transparent conductive film comprises the following steps:

[0051] Step (1) Pretreatment: The 6-inch glass substrate was cleaned with acetone, water, ethanol, and water ultrasonically for 15 minutes in sequence, and then vacuum dried after the cleaning treatment; the glass substrate was placed in a magnetron sputtering equipment chamber and then vacuumed to 3.0×10 -6 Pa;

[0052] Step (2) magnetron sputtering: using an ITO material having a weight ratio of tin oxide to indium oxide of 10:90 as a target material, depositing an ITO film with a thickness of 100 nm on the surface of the glass substrate by magnetron sputtering at room temperature; wherein the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the distance between the target material and the substrate is 55 mm, the magnetron sputtering power is 45 W, the magnetron sputtering gas is composed of oxygen with a flow rate of 2 sccm and argon with a flow rate of 120 sccm, and the pressure of the magnetron sputtering gas is 0.3 Pa;

[0053] Step (3) Gradient freezing: The ITO film layer is subjected to gradient freezing treatment, firstly cooling from room temperature to -35°C at a cooling rate of 5°C / min, and maintaining for 45 minutes; then cooling to -55°C at a cooling rate of 1°C / min, and maintaining for 70 minutes; then placing in a room temperature environment and restoring to room temperature, to obtain a first ITO film;

[0054] Step (4) microwave-ultrasonic synergistic treatment: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic synergistic treatment to obtain a second ITO film; wherein the working condition parameters of the microwave-ultrasonic synergistic treatment include: microwave power of 720 W, ultrasonic power of 115 W, and time of 40 seconds;

[0055] Step (5) Alternating cycle treatment: the second ITO film is subjected to alternating cycle treatment according to the steps (3) and (4) for 5 times in sequence to obtain the low-resistance transparent conductive film.

[0056] 10 points were selected on the obtained film for square resistance detection, and the square resistance average value (arithmetic mean) was calculated; at the same time, according to the formula: square resistance uniformity (%) = (maximum square resistance - minimum square resistance) ÷ 2 ÷ square resistance average value × 100%, the smaller the square resistance uniformity value, the better the square resistance uniformity. The test results are shown in Table 1. Example 2

[0057] This example provides a low-resistance transparent conductive film, and the preparation method of the low-resistance transparent conductive film comprises the following steps:

[0058] Step (1) Pretreatment: The 6-inch glass substrate was cleaned with acetone, water, ethanol, and water ultrasonically for 15 minutes in sequence, and then vacuum dried after the cleaning treatment; the glass substrate was placed in a magnetron sputtering equipment chamber and then vacuumed to 3.0×10 -6 Pa;

[0059] Step (2) magnetron sputtering: using an ITO material having a weight ratio of tin oxide to indium oxide of 10:90 as a target material, depositing an ITO film with a thickness of 95 nm on the surface of the glass substrate by magnetron sputtering at room temperature; wherein the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the distance between the target material and the substrate is 60 mm, the magnetron sputtering power is 30 W, the magnetron sputtering gas is composed of oxygen with a flow rate of 1 sccm and argon with a flow rate of 110 sccm, and the pressure of the magnetron sputtering gas is 0.2 Pa;

[0060] Step (3) Gradient freezing: subjecting the ITO film layer to gradient freezing treatment, first cooling from room temperature to -30°C at a cooling rate of 5°C / min, and maintaining for 60 minutes; then cooling to -60°C at a cooling rate of 1°C / min, and maintaining for 60 minutes; then placing in a room temperature environment and restoring to room temperature, to obtain a first ITO film;

[0061] Step (4) microwave-ultrasonic synergistic treatment: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic synergistic treatment to obtain a second ITO film; wherein the working condition parameters of the microwave-ultrasonic synergistic treatment include: microwave power of 625 W, ultrasonic power of 80 W, and time of 60 seconds;

[0062] Step (5) Alternating cycle treatment: The second ITO film is subjected to alternating cycle treatment according to step (3) and step (4) for 6 times in sequence to obtain the low-resistance transparent conductive film.

[0063] The average square resistance and uniform square resistance of the transparent conductive film obtained in this example were obtained according to the detection and calculation method in Example 1. The results are shown in Table 1. Example 3

[0064] This example provides a low-resistance transparent conductive film, and the preparation method of the low-resistance transparent conductive film comprises the following steps:

[0065] Step (1) Pretreatment: The 6-inch glass substrate was cleaned with acetone, water, ethanol, and water ultrasonically for 15 minutes in sequence, and then vacuum dried after the cleaning treatment; the glass substrate was placed in a magnetron sputtering equipment chamber and then vacuumed to 3.0×10 -6 Pa;

[0066] Step (2) magnetron sputtering: using an ITO material having a weight ratio of tin oxide to indium oxide of 10:90 as a target material, depositing an ITO film with a thickness of 95 nm on the surface of the glass substrate by magnetron sputtering at room temperature; wherein the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the distance between the target material and the substrate is 50 mm, the magnetron sputtering power is 60 W, the magnetron sputtering gas is composed of oxygen with a flow rate of 5 sccm and argon with a flow rate of 130 sccm, and the pressure of the magnetron sputtering gas is 0.5 Pa;

[0067] Step (3) Gradient freezing: The ITO film layer is subjected to gradient freezing treatment, firstly cooling from room temperature to -40°C at a cooling rate of 5°C / min, and maintaining for 30 minutes; then cooling to -50°C at a cooling rate of 1°C / min, and maintaining for 90 minutes; then placing in a room temperature environment and restoring to room temperature, to obtain a first ITO film;

[0068] Step (4) microwave-ultrasonic synergistic treatment: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic synergistic treatment to obtain a second ITO film; wherein the working condition parameters of the microwave-ultrasonic synergistic treatment include: microwave power of 800 W, ultrasonic power of 150 W, and time of 30 seconds;

[0069] Step (5) Alternating cycle treatment: the second ITO film is subjected to alternating cycle treatment according to the steps (3) and (4) for four times in sequence to obtain the low-resistance transparent conductive film.

[0070] The average square resistance and uniform square resistance of the transparent conductive film obtained in this example were obtained according to the detection and calculation method in Example 1. The results are shown in Table 1.

[0071] Comparative Example 1

[0072] This example provides a transparent conductive film and a method for preparing the same. The difference from Example 1 is that step (3), step (4) and step (5) in Example 1 are not performed; the remaining steps and parameters are the same.

[0073] The method for preparing the transparent conductive film comprises the following steps:

[0074] Step (1) Pretreatment: The 6-inch glass substrate was cleaned with acetone, water, ethanol, and water ultrasonically for 15 minutes in sequence, and then vacuum dried after the cleaning treatment; the glass substrate was placed in a magnetron sputtering equipment chamber and then vacuumed to 3.0×10 -6 Pa;

[0075] Step (2) magnetron sputtering: using an ITO material having a weight ratio of tin oxide to indium oxide of 10:90 as a target material, a 100 nm thick ITO film (i.e., a transparent conductive film) is deposited on the surface of the glass substrate by a magnetron sputtering method at room temperature; wherein the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the distance between the target material and the substrate is 55 mm, the magnetron sputtering power is 45 W, the magnetron sputtering gas is composed of oxygen with a flow rate of 2 sccm and argon with a flow rate of 120 sccm, and the pressure of the magnetron sputtering gas is 0.3 Pa.

[0076] The average square resistance and uniform square resistance of the transparent conductive film obtained in this example were obtained according to the detection and calculation method in Example 1. The results are shown in Table 1.

[0077] Comparative Example 2

[0078] This example provides a transparent conductive film and a preparation method thereof, which is different from Example 1 only in that the gradient freezing in Example 1 is not performed; the remaining steps and parameters are the same.

[0079] The method for preparing the transparent conductive film comprises the following steps:

[0080] Step (1) Pretreatment: The 6-inch glass substrate was cleaned with acetone, water, ethanol, and water ultrasonically for 15 minutes in sequence, and then vacuum dried after the cleaning treatment; the glass substrate was placed in a magnetron sputtering equipment chamber and then vacuumed to 3.0×10 -6 Pa;

[0081] Step (2) magnetron sputtering: using an ITO material having a weight ratio of tin oxide to indium oxide of 10:90 as a target material, depositing an ITO film with a thickness of 100 nm on the surface of the glass substrate by magnetron sputtering at room temperature; wherein the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the distance between the target material and the substrate is 55 mm, the magnetron sputtering power is 45 W, the magnetron sputtering gas is composed of oxygen with a flow rate of 2 sccm and argon with a flow rate of 120 sccm, and the pressure of the magnetron sputtering gas is 0.3 Pa;

[0082] Step (3) microwave-ultrasonic synergistic treatment: placing the ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic synergistic treatment to obtain a first ITO film; wherein the working condition parameters of the microwave-ultrasonic synergistic treatment include: microwave power of 720 W, ultrasonic power of 115 W, and time of 40 seconds;

[0083] Step (4) cyclic treatment: the first ITO film is cyclically treated 5 times according to the step (3) to obtain the transparent conductive film.

[0084] The average square resistance and uniform square resistance of the transparent conductive film obtained in this example were obtained according to the detection and calculation method in Example 1. The results are shown in Table 1.

[0085] Comparative Example 3

[0086] This example provides a transparent conductive film and a preparation method thereof, which is different from Example 1 only in that the microwave-ultrasonic coordinated treatment in Example 1 is not performed; the remaining steps and parameters are the same.

[0087] The method for preparing the transparent conductive film comprises the following steps:

[0088] Step (1) Pretreatment: The 6-inch glass substrate was cleaned with acetone, water, ethanol, and water ultrasonically for 15 minutes in sequence, and then vacuum dried after the cleaning treatment; the glass substrate was placed in a magnetron sputtering equipment chamber and then vacuumed to 3.0×10 -6 Pa;

[0089] Step (2) magnetron sputtering: using an ITO material having a weight ratio of tin oxide to indium oxide of 10:90 as a target material, depositing an ITO film with a thickness of 100 nm on the surface of the glass substrate by magnetron sputtering at room temperature; wherein the working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the distance between the target material and the substrate is 55 mm, the magnetron sputtering power is 45 W, the magnetron sputtering gas is composed of oxygen with a flow rate of 2 sccm and argon with a flow rate of 120 sccm, and the pressure of the magnetron sputtering gas is 0.3 Pa;

[0090] Step (3) Gradient freezing: The ITO film layer is subjected to gradient freezing treatment, firstly cooling from room temperature to -35°C at a cooling rate of 5°C / min, and maintaining for 45 minutes; then cooling to -55°C at a cooling rate of 1°C / min, and maintaining for 70 minutes; then placing in a room temperature environment and restoring to room temperature, to obtain a first ITO film;

[0091] Step (4) cyclic treatment: the first ITO film is cyclically treated 5 times according to the step (3) to obtain the transparent conductive film.

[0092] The average square resistance and uniform square resistance of the transparent conductive film obtained in this example were obtained according to the detection and calculation method in Example 1. The results are shown in Table 1.

[0093] Comparative Example 4

[0094] This example provides a transparent conductive film and a preparation method thereof, which differs from Example 1 only in that the microwave power in step (4) microwave-ultrasonic coordinated treatment is adjusted to 150 W and the ultrasonic power is adjusted to 820 W; the remaining steps and parameters are the same.

[0095] The average square resistance and uniform square resistance of the transparent conductive film obtained in this example were obtained according to the detection and calculation method in Example 1. The results are shown in Table 1.

[0096] Table 1

[0097] Test samples Average square resistance (Ω / □) Square resistance uniformity (%) Example 1 26.9 5.4 Example 2 40.3 9.0 Example 3 34.7 7.8 Comparative Example 1 91.2 20.6 Comparative Example 2 57.8 14.1 Comparative Example 3 79.4 18.5 Comparative Example 4 48.1 11.7

[0098] It can be seen from Table 1 that compared with comparative examples 1 to 4, the transparent conductive films provided by embodiments 1 to 3 of the present invention have lower square resistance and better uniformity, indicating that the present invention introduces a gradient freezing process and a microwave-ultrasonic coordinated treatment process to jointly modify the ITO film, and the two show a significant synergistic effect, thereby achieving the preparation of large-size ITO films with low resistance and high uniformity at room temperature.

[0099] In summary, the embodiments of the present invention provide a low-resistance transparent conductive film and a method for preparing the same. For the existing ITO film preparation process, the present invention introduces a gradient freezing process and a microwave-ultrasonic collaborative processing process to jointly modify the ITO film, thereby achieving the preparation of large-size ITO films with low resistance and high uniformity at room temperature.

[0100] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which are applicable regardless of the range. In addition, whenever a numerical range is indicated herein, it is intended to include any cited number (fractional or integer) within the indicated range.

[0101] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a low-resistance transparent conductive film, characterized in that: The preparation method comprises the following steps: S1: forming an ITO thin film on the substrate surface by magnetron sputtering at room temperature; S2: subjecting the ITO film layer to a gradient freezing treatment, and then restoring the layer to room temperature to obtain a first ITO film; S3: placing the first ITO film in a microwave-ultrasonic composite field for microwave-ultrasonic coordinated treatment to obtain a second ITO film; S4: treating the second ITO film in alternating cycles according to the steps S2 and S3 to obtain the low-resistance transparent conductive film; The working condition parameters of the microwave-ultrasonic coordinated treatment include: microwave power of 650-800W, ultrasonic power of 80-150W, and time of 30-60 seconds.

2. The method for preparing a low-resistance transparent conductive film according to claim 1, characterized in that: The microwave power is 720W, and the ultrasonic power is 115W.

3. The method for preparing a low-resistance transparent conductive film according to claim 1, characterized in that: The low-resistance transparent conductive film is a single-layer ITO film not doped with other elements, and the other elements are elements other than In, Sn and O.

4. The method for preparing a low-resistance transparent conductive film according to claim 1, characterized in that: The gradient freezing treatment step includes the following processes: The first stage: cool down from room temperature to -40~-30℃ at a cooling rate of 5℃ / min and keep it for 30~60 minutes; The second stage: continue cooling to -60~-50℃ at a cooling rate of 1℃ / min and maintain for 60~90 minutes.

5. The method for preparing a low-resistance transparent conductive film according to claim 1, characterized in that: The substrate comprises a substrate having a size of 6 inches.

6. The method for preparing a low-resistance transparent conductive film according to claim 1 or 5, characterized in that: The working condition parameters of the magnetron sputtering method include: the substrate temperature is room temperature, the ITO material with a weight ratio of tin oxide to indium oxide of 10:90 is used as the target material, the distance between the target material and the substrate is 50~60mm, the magnetron sputtering power is 30~60W, the magnetron sputtering gas is composed of oxygen with a flow rate of 1~5sccm and argon with a flow rate of 110~130sccm, and the pressure of the magnetron sputtering gas is 0.2~0.5Pa.

7. The method for preparing a low-resistance transparent conductive film according to claim 1, characterized in that: The thickness of the ITO film is 95-110 nm.

8. The method for preparing a low-resistance transparent conductive film according to claim 1, characterized in that: The number of times of the alternating cycle treatment is 4 to 6 times.

9. A low-resistance transparent conductive film, characterized in that: The low-resistance transparent conductive film is prepared by the method for preparing a low-resistance transparent conductive film according to any one of claims 1 to 8.

10. The low-resistance transparent conductive film according to claim 9, characterized in that: The property parameters of the low-resistance transparent conductive film include: an average square resistance value of less than 40Ω / □, and a square resistance uniformity of less than 10%.

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