Method for preparing flexible crystalline indium tin oxide transparent conductive thin film by adopting silver film etching and application of flexible crystalline indium tin oxide transparent conductive thin film

Abstract

The invention relates to a method for preparing a flexible crystalline indium tin oxide transparent conductive film by adopting silver film etching and application. The problems that the photoelectric property is poor and the preparation process of a high-performance flexible ITO film is complicated due to the fact that an amorphous ITO film is directly deposited on an existing flexible substrate are solved. The preparation method comprises the following steps: 1, carrying out ultrasonic cleaning on metal Ag, a ceramic ITO target material and a silicon wafer; 2, an Ag film and an ITO film are deposited on the silicon wafer substrate, and annealing treatment is carried out at the temperature of 200-500 DEG C; and 3, dropwise adding the pre-polymerized liquid on the surface of the crystalline ITO thin film, carrying out spin-coating treatment to obtain a silicon wafer / Ag / ITO / PDMS sample, and carrying out Ag film etching to obtain the flexible crystalline indium tin oxide transparent conductive thin film. According to the invention, the material preparation limitation that annealing treatment cannot be carried out after the flexible substrate is plated with the ITO film and a direct plating interface is easy to fall off is made up, the prepared flexible ITO film has good conductivity, and the transmittance of a visible light wave band is about 90%.

Description

Technical Field

[0001] The invention belongs to the field of transparent conductive film preparation, and particularly relates to a method for preparing a flexible crystalline indium tin oxide transparent conductive film by etching a silver film and its application. Background Art

[0002] Indium tin oxide film has the characteristics of high transparency in the visible range, excellent conductivity, and good chemical stability. It is one of the most widely used transparent conductive film materials and has become one of the indispensable key materials in many modern electronic devices.

[0003] With the rise of flexible electronic products such as wearable devices and bendable displays, the demand for flexible ITO films is also increasing. Compared with the hard substrate ITO films with mature processes, the current preparation of flexible ITO films has the following difficulties: 1) ITO films need to be annealed at high temperature to be crystalline to have high optoelectronic properties, but flexible organic substrates cannot withstand high temperatures; 2) The surface of the flexible substrate does not match the film material well, and the film is easy to fall off; 3) Flexible organic substrates are mostly elastic materials, and substrate warping can easily lead to poor uniformity. Therefore, the process of preparing flexible ITO films is relatively complicated, and factors such as the characteristics of the substrate, the composition and structure of the film need to be considered, and precise control of process parameters is required to ensure the performance and stability of the film. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the photoelectric performance of the amorphous ITO film directly deposited on the existing flexible substrate is poor and the preparation process of the high-performance flexible ITO film is complicated and cumbersome, and to provide a method and application of preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching.

[0005] The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching is implemented according to the following steps:

[0006] 1. Cleaning of substrate and target:

[0007] The metal Ag target and the ceramic ITO target are placed in acetone, alcohol and deionized water for ultrasonic cleaning in turn to obtain clean Ag target and ITO target;

[0008] The silicon wafer is placed in acetone, alcohol and deionized water in turn for ultrasonic cleaning to obtain a clean silicon wafer substrate;

[0009] 2. Preparation of crystalline ITO film:

[0010] ①. Preparation before plating: Install the clean Ag target, ITO target and clean silicon wafer substrate in the chamber of the magnetron sputtering equipment in sequence, and evacuate the chamber to a pressure of 6×10 -4 Pa~4×10 -4Pa;

[0011] ②, Sputtering Ag film: introduce argon gas to a pressure of 3-5Pa, use Ag target material, the coating power supply is a DC power supply, control the coating power to be 30-40W, pre-sputter for 3-5min under a pressure of 0.5-1Pa, open the target baffle, and perform magnetron sputtering at a pressure of 0.5-1Pa to deposit an Ag film on the silicon wafer substrate;

[0012] ③. Sputtering thin film: introduce argon gas to a pressure of 3-5 Pa, rotate the sample stage target to the bottom of the ITO target, use a radio frequency power supply for the coating, control the coating power to 80-100 W, pre-sputter for 5-10 minutes under a pressure of 0.5-1 Pa, open the target baffle, and perform magnetron sputtering at a pressure of 0.5-1 Pa to obtain a silicon wafer substrate with a Ag-ITO film deposited thereon;

[0013] ④, post-annealing: turn on the heating power supply, control the heating rate to 5-10°C / min, and anneal the silicon wafer substrate with the Ag-ITO film deposited at a temperature of 200-500°C;

[0014] ⑤. Shutdown: Turn off all power supplies, wait until the temperature inside the cabin drops to room temperature, open the vent valve to release air, and obtain a silicon wafer substrate with a crystalline ITO film;

[0015] 3. Preparation of flexible ITO film:

[0016] ①. Preparation of flexible substrate: Add the monomer and curing liquid of polydimethylsiloxane into the container, stir them thoroughly and then perform vacuum defoaming treatment. After the internal bubbles disappear completely, the prepolymerized liquid is obtained.

[0017] ②, Substrate spin coating: Place the silicon wafer substrate with crystalline ITO film on the tray of the spin coater, drop the prepolymerized liquid on the surface of the crystalline ITO film, and obtain the silicon wafer / Ag / ITO / PDMS sample after spin coating and drying;

[0018] ③. Ag film etching: Dissolve iodine and potassium iodide particles in acetonitrile solution at a molar ratio of 1:10, then immerse the silicon wafer / Ag / ITO / PDMS sample to etch the Ag film. After cleaning and drying, a flexible crystalline indium tin oxide transparent conductive film is obtained.

[0019] The application of the flexible crystalline indium tin oxide transparent conductive film prepared by the present invention is to use the flexible crystalline indium tin oxide transparent conductive film as a transparent conductive electrode in a photoelectric device.

[0020] Wherein, the optoelectronic device can be selected from solar cells, OLEDs or OTFTs.

[0021] The present invention uses Ag film as the intermediate layer between the hard substrate and the ITO film, obtains a crystalline ITO film under vacuum annealing conditions, and subsequently adopts a method of spin coating a flexible substrate on the ITO surface and etching the Ag film with iodine triions to obtain a flexible substrate crystalline ITO film, which makes up for the material preparation limitations that the flexible substrate cannot be annealed after being plated with the ITO film and the direct plating interface is easy to fall off.

[0022] The method of preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching of the present invention has the following beneficial effects:

[0023] 1. The present invention adopts a method of etching after annealing to prepare a flexible crystalline ITO film, which combines the two methods of magnetron sputtering and spin coating. The cost of preparing the flexible crystalline ITO film is low and the process operation is simple.

[0024] 2. The flexible ITO film prepared by the present invention has good transparent conductive properties, a visible light transmittance of 90%, good bendability, and a resistivity of 6.5×10 -4 Ω·cm, and the critical bending radius is 5.5mm, which is suitable for the production of flexible optoelectronic devices and greatly expands the application scope of flexible ITO films. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of a method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to the present invention;

[0026] Figure 2 The XRD pattern of the crystalline ITO film prepared in the embodiment;

[0027] Figure 3 This is a physical display of the flexible crystalline indium tin oxide transparent conductive film prepared in the example;

[0028] Figure 4 This is a visible light transmittance test curve of the flexible crystalline indium tin oxide transparent conductive film prepared in the example;

[0029] Figure 5 This is a graph showing the electrical properties of the flexible crystalline indium tin oxide transparent conductive film prepared in the example. DETAILED DESCRIPTION

[0030] Specific implementation method 1: In this implementation method, a method for preparing a flexible crystalline indium tin oxide transparent conductive film by etching a silver film is implemented according to the following steps:

[0031] 1. Cleaning of substrate and target:

[0032] The metal Ag target and the ceramic ITO target are placed in acetone, alcohol and deionized water for ultrasonic cleaning in turn to obtain clean Ag target and ITO target;

[0033] The silicon wafer is placed in acetone, alcohol and deionized water in turn for ultrasonic cleaning to obtain a clean silicon wafer substrate;

[0034] 2. Preparation of crystalline ITO film:

[0035] ①. Preparation before plating: Install the clean Ag target, ITO target and clean silicon wafer substrate in the chamber of the magnetron sputtering equipment in sequence, and evacuate the chamber to a pressure of 6×10 -4 Pa~4×10 -4 Pa;

[0036] ②, Sputtering Ag film: introduce argon gas to a pressure of 3-5Pa, use Ag target material, the coating power supply is a DC power supply, control the coating power to be 30-40W, pre-sputter for 3-5min under a pressure of 0.5-1Pa, open the target baffle, and perform magnetron sputtering at a pressure of 0.5-1Pa to deposit an Ag film on the silicon wafer substrate;

[0037] ③. Sputtering thin film: introduce argon gas to a pressure of 3-5 Pa, rotate the sample stage target to the bottom of the ITO target, use a radio frequency power supply for the coating, control the coating power to 80-100 W, pre-sputter for 5-10 minutes under a pressure of 0.5-1 Pa, open the target baffle, and perform magnetron sputtering at a pressure of 0.5-1 Pa to obtain a silicon wafer substrate with a Ag-ITO film deposited thereon;

[0038] ④, post-annealing: turn on the heating power supply, control the heating rate to 5-10°C / min, and anneal the silicon wafer substrate with the Ag-ITO film deposited at a temperature of 200-500°C;

[0039] ⑤. Shutdown: Turn off all power supplies, wait until the temperature inside the cabin drops to room temperature, open the vent valve to release air, and obtain a silicon wafer substrate with a crystalline ITO film;

[0040] 3. Preparation of flexible ITO film:

[0041] ①. Preparation of flexible substrate: Add the monomer and curing liquid of polydimethylsiloxane into the container, stir them thoroughly and then perform vacuum defoaming treatment. After the internal bubbles disappear completely, the prepolymerized liquid is obtained.

[0042] ②, Substrate spin coating: Place the silicon wafer substrate with crystalline ITO film on the tray of the spin coater, drop the prepolymerized liquid on the surface of the crystalline ITO film, and obtain the silicon wafer / Ag / ITO / PDMS sample after spin coating and drying;

[0043] ③. Ag film etching: Dissolve iodine and potassium iodide particles in acetonitrile solution at a molar ratio of 1:10, then immerse the silicon wafer / Ag / ITO / PDMS sample to etch the Ag film. After cleaning and drying, a flexible crystalline indium tin oxide transparent conductive film is obtained.

[0044] In the present embodiment, the annealing temperature in step ④ of step 2 is preferably 300°C.

[0045] Specific implementation method 2: The difference between this implementation method and specific implementation method 1 is that in step 1, during the ultrasonic cleaning of metal Ag and ceramic ITO target materials, the ultrasonic power is controlled to be 100W to 200W.

[0046] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that the ultrasonic power is controlled to be 50W to 100W during the ultrasonic cleaning of the silicon wafer in step one.

[0047] Specific implementation method 4: The difference between this implementation method and any one of specific implementation methods 1 to 3 is that the thickness of the Ag film deposited on the silicon wafer substrate in step ② of step 2 is 40 to 50 nm.

[0048] Specific implementation mode 5: This implementation mode is different from specific implementation modes 1 to 4 in that the thickness of the ITO film deposited on the silicon wafer substrate in step ③ of step 2 is 400 to 500 nm.

[0049] Specific implementation example 6: This implementation example is different from specific implementation examples 1 to 5 in that in step ④ of step 2, the silicon wafer substrate with the Ag-ITO film deposited thereon is annealed at a temperature of 300° C. for 30 to 40 minutes.

[0050] Specific embodiment 7: The difference between this embodiment and any one of specific embodiments 1 to 6 is that in step 1 of step 3, the mass ratio of the polydimethylsiloxane monomer to the curing liquid is 5:1 to 10:1.

[0051] Specific embodiment eight: The difference between this embodiment and specific embodiments one to seven is that the vacuum defoaming treatment in step three (1) is carried out in a vacuum drying oven at 25° C. for 30 to 40 minutes.

[0052] Specific embodiment 9: The difference between this embodiment and specific embodiments 1 to 8 is that the spin coating process in step ② of step 3 is carried out at a speed of 500 to 1000 rpm for 2 to 3 minutes.

[0053] Specific embodiment ten: The difference between this embodiment and specific embodiments one to nine is that the drying process in step ② of step three is to maintain the temperature at 60-80° C. in a vacuum drying oven for 1-2 hours.

[0054] Embodiment 1: The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching in this embodiment is implemented according to the following steps:

[0055] 1. Cleaning of substrate and target:

[0056] Under an ultrasonic power of 100 W, the metal Ag target and the ceramic ITO target were ultrasonically cleaned in acetone, alcohol and deionized water for 15 min respectively to obtain clean Ag target and ITO target.

[0057] At an ultrasonic power of 50 W, a silicon wafer with a size of 20 mm × 20 mm × 1 mm was placed in acetone, alcohol and deionized water for ultrasonic cleaning in turn to obtain a clean silicon wafer substrate;

[0058] 2. Preparation of crystalline ITO film:

[0059] ①. Preparation before plating: Install the clean Ag target, ITO target and clean silicon wafer substrate in the chamber of the magnetron sputtering equipment in sequence, and evacuate the chamber to a pressure of 6×10 -4 Pa;

[0060] ②, Sputtering Ag film: introduce argon gas to a pressure of 3Pa, use Ag target material, the coating power supply is a DC power supply, control the coating power to 30W, pre-sputter for 5min under a pressure of 0.5Pa, open the target baffle, magnetron sputtering treatment for 5min under a pressure of 0.5Pa, the argon gas flow rate is 40sccm, and a 40nm thick Ag film is deposited on the silicon wafer substrate;

[0061] ③. Sputtering thin film: introduce argon gas to a pressure of 3Pa, rotate the sample stage target to the bottom of the ITO target, use a radio frequency power supply for the coating, control the coating power to 80W, pre-sputter for 5min at a pressure of 0.5Pa, open the target baffle, and perform magnetron sputtering for 60min at a pressure of 0.5Pa. The argon flow rate is 40sccm, and a silicon wafer substrate with a 500nm thick ITO film is obtained;

[0062] ④, Post-annealing: Turn on the heating power supply, control the heating rate to 5°C / min, and anneal the silicon wafer substrate with the ITO film deposited at 200°C for 30 minutes;

[0063] ⑤. Shutdown: Turn off all power supplies, wait until the temperature in the cabin drops to room temperature, open the air valve, and when the barometer displays atmospheric pressure, a silicon wafer substrate with a crystalline ITO film is obtained;

[0064] 3. Preparation of flexible ITO film:

[0065] ①. Preparation of flexible substrate: Add the main agent of polydimethylsiloxane monomer SK-184 and the curing liquid SK-184 hardener into the container in a ratio of 10:1, stir well and place in a vacuum drying oven (25°C) for 40 minutes, and obtain the prepolymerized liquid after the internal bubbles disappear completely;

[0066] ②, Substrate spin coating: Place the silicon wafer substrate with the crystalline ITO film on the tray of the spin coater, drop 1 mL of the prepolymerized liquid on the surface of the crystalline ITO film, run at 500 rpm for 2 min, and then cross-link in a vacuum drying oven at 80°C for 1 h to obtain a silicon wafer / Ag / ITO / PDMS sample;

[0067] ③. Ag film etching: Dissolve iodine and potassium iodide particles in acetonitrile solution at a molar ratio of 1:10, then immerse the silicon wafer / Ag / ITO / PDMS sample, wash with methanol and deionized water in turn and blow dry with nitrogen flow to obtain a flexible crystalline indium tin oxide transparent conductive film.

[0068] Embodiment 2: The difference between this embodiment and embodiment 1 is that in step ④ of step 2, the silicon wafer substrate with the ITO film deposited thereon is annealed at a temperature of 300°C.

[0069] Embodiment 3: The difference between this embodiment and embodiment 1 is that in step ④ of step 2, the silicon wafer substrate with the ITO film deposited thereon is annealed at a temperature of 400°C.

[0070] Embodiment 4: The difference between this embodiment and embodiment 1 is that in step ④ of step 2, the silicon wafer substrate deposited with the ITO film is annealed at a temperature of 500°C.

[0071] Figure 1 It is a schematic diagram of the process flow of the method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching in the embodiment.

[0072] Figure 2 These are the XRD patterns of amorphous and crystalline ITO films. It can be clearly seen that after vacuum annealing, the crystallinity of the ITO film is significantly improved.

[0073] Figure 3 This is a real picture of the flexible crystalline ITO film after etching and cleaning. It can be seen that the flexible ITO film has a certain degree of flexibility.

[0074] Figure 4It is a test curve diagram of the visible light transmittance of the flexible ITO film. The five curves are respectively the visible light range transmittance of the ITO films obtained at room temperature and in Examples 1 to 4. It can be seen from the figure that as the vacuum annealing temperature increases, the visible transmittance of the ITO film gradually increases to about 90%, and the flexible crystalline indium tin oxide transparent conductive film obtained at an annealing temperature of 300°C has the highest transmittance.

[0075] Figure 5 This is a test curve of the visible light transmittance of the flexible ITO film. It can be seen from the figure that the resistivity of the ITO film shows a trend of first decreasing and then increasing. The flexible crystalline indium tin oxide transparent conductive film obtained at the annealing temperature has the best conductivity, and its resistivity is 6.3×10 -4 Ω·cm.

Claims

1. A method for preparing a flexible crystalline indium tin oxide transparent conductive film by etching a silver film, characterized in that The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching is implemented by the following steps:

1. Cleaning of substrate and target: The metal Ag target and the ceramic ITO target are placed in acetone, alcohol and deionized water for ultrasonic cleaning in turn to obtain clean Ag target and ITO target; The silicon wafer is placed in acetone, alcohol and deionized water in turn for ultrasonic cleaning to obtain a clean silicon wafer substrate; 2. Preparation of crystalline ITO film: ①. Preparation before plating: Install the clean Ag target, ITO target and clean silicon wafer substrate in the chamber of the magnetron sputtering equipment in sequence, and evacuate the chamber to a pressure of 6×10 -4 Pa~4×10 -4 Pa; ②, Sputtering Ag film: introduce argon gas to a pressure of 3-5Pa, use Ag target material, the coating power supply is a DC power supply, control the coating power to be 30-40W, pre-sputter for 3-5min under a pressure of 0.5-1Pa, open the target baffle, and perform magnetron sputtering at a pressure of 0.5-1Pa to deposit an Ag film on the silicon wafer substrate; ③. Sputtering thin film: introduce argon gas to a pressure of 3-5 Pa, rotate the sample stage target to the bottom of the ITO target, use a radio frequency power supply for the coating, control the coating power to 80-100 W, pre-sputter for 5-10 minutes under a pressure of 0.5-1 Pa, open the target baffle, and perform magnetron sputtering at a pressure of 0.5-1 Pa to obtain a silicon wafer substrate with a Ag-ITO film deposited thereon; ④, post-annealing: turn on the heating power supply, control the heating rate to 5-10°C / min, and anneal the silicon wafer substrate with the Ag-ITO film deposited at a temperature of 200-500°C; ⑤. Shutdown: Turn off all power supplies, wait until the temperature inside the cabin drops to room temperature, open the vent valve to release air, and obtain a silicon wafer substrate with a crystalline ITO film; 3. Preparation of flexible ITO film: ①. Preparation of flexible substrate: Add the monomer and curing liquid of polydimethylsiloxane into the container, stir them thoroughly and then perform vacuum defoaming treatment. After the internal bubbles disappear completely, the prepolymerized liquid is obtained. ②, Substrate spin coating: Place the silicon wafer substrate with crystalline ITO film on the tray of the spin coater, drop the prepolymerized liquid on the surface of the crystalline ITO film, and obtain the silicon wafer / Ag / ITO / PDMS sample after spin coating and drying; ③. Ag film etching: Dissolve iodine and potassium iodide particles in acetonitrile solution at a molar ratio of 1:10, then immerse the silicon wafer / Ag / ITO / PDMS sample to etch the Ag film. After cleaning and drying, a flexible crystalline indium tin oxide transparent conductive film is obtained.

2. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step 1, during the ultrasonic cleaning of the metal Ag and ceramic ITO target materials, the ultrasonic power is controlled to be 100W to 200W.

3. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step ② of step 2, the thickness of the Ag film deposited on the silicon wafer substrate is 40 to 50 nm.

4. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step ③ of step 2, the thickness of the ITO film deposited on the silicon wafer substrate is 400 to 500 nm.

5. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step ④ of step 2, the silicon wafer substrate deposited with the Ag-ITO film is annealed at a temperature of 300° C. for 30 to 40 minutes.

6. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step 3, the mass ratio of the polydimethylsiloxane monomer to the curing liquid in step ① is 5:1 to 10:

1.

7. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step 3, step ① of the vacuum defoaming treatment is to vacuum dry the product in a vacuum oven at 25° C. for 30 to 40 minutes.

8. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that In step ② of step 3, the spin coating process is performed at a speed of 500 to 1000 rpm for 2 to 3 minutes.

9. The method for preparing a flexible crystalline indium tin oxide transparent conductive film by silver film etching according to claim 1, characterized in that The drying process of step ② in step 3 is to maintain the temperature at 60-80° C. in a vacuum drying oven for 1-2 hours.

10. Use of the flexible crystalline indium tin oxide transparent conductive film prepared as claimed in claim 1, characterized in that The flexible crystalline indium tin oxide transparent conductive film is used as a transparent conductive electrode in a photoelectric device.

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