Transparent conductive oxide ITO (Indium Tin Oxide) film as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a transparent conductive oxide ITO (Indium Tin Oxide) film, which comprises the following steps of: A1, selecting a silicon wafer, and depositing ITO transparent conductive layers on microcrystalline silicon layers on two surfaces of the silicon wafer; a2, after the ITO transparent conductive layer in the step A1 is prepared, the silicon wafer is placed in a microwave environment to be subjected to microwave treatment under the conditions that the frequency ranges from 1 GHz to 3 GHz, the power ranges from 500 W to 1200 W, the treatment time ranges from 30 seconds to 100 seconds, and then the transparent conductive oxide ITO thin film is prepared. The invention further discloses application of the transparent conductive oxide ITO thin film, and the application comprises the step of applying the transparent conductive oxide ITO thin film to preparation of a heterojunction solar cell so as to improve the electrical performance and the optical performance of the heterojunction solar cell. The transparent conductive oxide ITO thin film has high light transmittance and low sheet resistance, is applied to the heterojunction solar cell, and improves the photoelectric conversion efficiency and stability of the cell.

Description

Technical Field

[0001] The invention relates to the technical field of ITO film preparation, and in particular to a transparent conductive oxide ITO film and a preparation method and application thereof. Background Art

[0002] In the preparation process of crystalline silicon heterojunction solar cells (HJT), doped amorphous silicon thin films and intrinsic amorphous silicon thin films are usually deposited on both sides of the silicon wafer to form a heterojunction structure with the crystalline silicon substrate, change the bandgap width, and thus obtain a high open circuit voltage. The lateral electronic conductivity of the doped amorphous silicon film is poor, and it needs to be covered with a layer of transparent conductive oxide film (i.e., TCO film) for light transmission and current transmission. The TCO film is deposited on the surface of the substrate by physical vapor deposition (PVD) or reactive plasma deposition (RPD). PVD is the mainstream method for preparing TCO thin films in the industry. Its basic principle is to ionize Ar gas into Ar plasma under the action of electric and magnetic fields, and the accelerated high-energy particles (Ar) obtain high energy and bombard the target material. The atoms on the surface of the target material break away from the original lattice and escape. The sputtered particles are deposited on the surface of the substrate and react with oxygen atoms to form oxides. The coating principle of RPD is that Ar gas generates plasma through a plasma gun, enters the process chamber, and then guides the Ar plasma to hit the target material through a magnetic field, and the target material sublimates and deposits on the substrate. Both deposition methods require the use of target materials. Due to the difference in deposition principles, the material performance requirements for the target material are different. The indium tin oxide target (ITO target) used in existing photovoltaic HJT cells is mainly composed of indium oxide and tin oxide. The mass ratio of indium oxide to tin oxide is usually 90:10 or 97:3. While the high doping concentration of tin oxide brings high conductivity, the TCO film has a high absorption of light itself and a low transmittance of long-wavelength light, which makes it impossible to maximize the use of sunlight, which also seriously restricts the improvement of HJT cell efficiency.

[0003] How to improve the photoelectric conversion efficiency of solar cells has always been a research issue in the solar photovoltaic industry, and the reflection loss of light on the surface of solar cells is an important factor restricting the improvement of the photoelectric conversion efficiency of solar cells. Anti-reflection film can effectively reduce the light reflection loss on the silicon surface, thereby improving the conversion efficiency of solar cells. As a transparent conductive oxide film, tin-doped indium oxide (ITO) film has excellent conductivity and chemical stability. It is a very important anti-reflection film in crystalline silicon heterojunction solar cells, but its average visible light transmittance is low (less than 90%), and there are parasitic absorption losses and reflection losses in the ultraviolet and near-infrared regions, which reduces the efficiency of the cell. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a transparent conductive oxide ITO film, so as to solve the problem that the ITO film prepared by the conventional method has low visible light transmittance and has parasitic absorption loss and reflection loss in the ultraviolet and near-infrared regions.

[0005] In order to overcome the above defects of the prior art, the present invention provides a method for preparing a transparent conductive oxide ITO film, comprising the following steps:

[0006] A1: Select a silicon wafer and deposit an ITO transparent conductive layer on the microcrystalline silicon layer on both sides of the silicon wafer;

[0007] A2: After the ITO transparent conductive layer of step A1 is prepared, the silicon wafer is placed in a microwave environment for microwave treatment. The microwave treatment conditions are: frequency 1-3 GHz, power range 500-1200 W, and treatment time 30-100 seconds, so as to obtain a transparent conductive oxide ITO film.

[0008] Compared with the prior art, the preparation method of a transparent conductive oxide ITO film in the present invention has the following advantages: in the preparation method of the present invention, oxygen vacancies are introduced into the ITO film by microwave treatment, and the ITO film is selectively heated, thereby improving the crystallinity of the ITO film, thereby significantly improving its electrical and optical properties, providing a transparent conductive oxide ITO film suitable for improving the photoelectric conversion efficiency of heterojunction solar cells, and the preparation method is simple to operate and has low cost.

[0009] In a possible implementation, in step A1, the conditions for depositing the ITO transparent conductive layer include: a silicon wafer temperature of 100-200° C., a tin oxide content of 3-10 wt % in the ITO film, and an ITO film deposition thickness of 50-100 nm.

[0010] In a possible implementation, in step A1, the conditions for depositing the ITO transparent conductive layer include: a silicon wafer temperature of 150° C., a tin oxide content of 5% in the ITO film, and an ITO film deposition thickness of 80 nm.

[0011] In a possible implementation, in step A2, the microwave treatment conditions are: frequency 2 GHz, power 800 W, and treatment time 60 seconds.

[0012] Through the above possible implementations, the present invention improves the average transmittance of the indium tin oxide (ITO) film in the visible light range by controlling the deposition and microwave treatment of the film, and the increase in surface roughness helps to reduce light reflection and improve light absorption, thereby improving the efficiency of heterojunction solar cells. The second technical problem to be solved by the present invention is to provide a transparent conductive oxide ITO film, which is prepared by the above preparation method.

[0013] Compared with the prior art, the transparent conductive oxide ITO film of the present invention has the following advantages: compared with the conventional technical means in the field, the transparent conductive oxide ITO film of the present invention has a higher crystallinity after microwave treatment, the impedance of the film is significantly reduced, and the conductivity and charge transfer capacity of the ITO film are enhanced. A lower film square resistance is achieved, and therefore higher electrical and optical properties are also achieved.

[0014] The third technical problem to be solved by the present invention is to provide an application of a transparent conductive oxide ITO film, which includes applying the transparent conductive oxide ITO film to the preparation of heterojunction solar cells to improve the electrical and optical properties of the heterojunction solar cells, thereby solving the problems of poor conductivity and chemical stability and low battery efficiency of conventional solar cells in the prior art.

[0015] In order to solve the above technical problems, the present invention provides an application of a transparent conductive oxide ITO film, wherein the application includes applying the transparent conductive oxide ITO film to the preparation of a heterojunction solar cell, and the application includes:

[0016] Preparation of heterojunction solar cells:

[0017] S1: cleaning the silicon wafer and then texturing it to form a texture layer on both sides of the silicon wafer, and further depositing an intrinsic amorphous silicon layer and a doped microcrystalline silicon layer on the texture layers on both sides, wherein the front side is an N-type doped microcrystalline silicon layer and the back side is a P-type doped microcrystalline silicon layer;

[0018] S2: Depositing the transparent conductive oxide ITO film on the surface of the doped microcrystalline silicon layer on the front and back sides of the silicon wafer processed in step S1;

[0019] S3: preparing electrodes on the transparent conductive oxide ITO film deposited in step S2, and finally completing the preparation of the heterojunction solar cell.

[0020] Compared with the prior art, the application of a transparent conductive oxide ITO film in the present invention has the following advantages: the application of a transparent conductive oxide ITO film in the present invention utilizes microwave treatment to selectively heat the ITO film to generate oxygen vacancies inside it, and this selective heating is only for the ITO film; microwave treatment can effectively introduce oxygen vacancies in the ITO lattice through selective heating, thereby improving its electrical properties. These oxygen vacancies improve the conductivity of ITO by promoting the movement of charge carriers. The generation of oxygen vacancies helps to reduce interface scattering and prolong the lifetime of carriers, thereby improving the overall electrical properties of the ITO film. The ITO film after microwave treatment shows significantly improved photoelectric properties, including higher transmittance and lower square resistance. These performance improvements are crucial for solar cell applications and help to improve the photoelectric conversion efficiency of solar cells.

[0021] In a possible implementation, in the step S1, the thickness of the intrinsic amorphous silicon layer is 3-15 nm, and the thickness of the doped microcrystalline layer is 10-50 nm.

[0022] In a possible implementation, in step S1, the thickness of the intrinsic amorphous silicon layer is 5 nm, and the thickness of the doped microcrystalline layer is 30 nm.

[0023] Through the above possible implementations, the present invention optimizes the surface roughness and crystallinity of the film by controlling these conditions, improves the light absorption capacity and current density of the solar cell, and thus significantly improves the overall efficiency of the solar cell.

[0024] In a possible implementation, in step S3, the electrode is a silver paste electrode, and the silver paste electrode is fixed on the transparent conductive oxide ITO film by printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a scanning electron microscope image of the ITO film in Example 1;

[0026] Figure 2 The surface atomic force microscope morphology of the ITO film in Example 1. DETAILED DESCRIPTION

[0027] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0028] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0029] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0030] The present invention provides a method for preparing a transparent conductive oxide ITO film, comprising the following steps:

[0031] A1: Select a silicon wafer and deposit an ITO transparent conductive layer on the microcrystalline silicon layer on both sides of the silicon wafer;

[0032] A2: After the ITO transparent conductive layer of step A1 is prepared, the silicon wafer is placed in a microwave environment for microwave treatment. The microwave treatment conditions are: frequency 1-3 GHz, power range 500-1200 W, and treatment time 30-100 seconds, so as to obtain a transparent conductive oxide ITO film.

[0033] As a preferred solution, in step A1, the conditions for depositing the ITO transparent conductive layer include: silicon wafer temperature 100-200° C., tin oxide content in the ITO film 3-10wt%, and ITO film deposition thickness 50-100nm.

[0034] As a preferred solution, in step A1, the conditions for depositing the ITO transparent conductive layer include: silicon wafer temperature of 150° C., tin oxide content in the ITO film of 5%, and ITO film deposition thickness of 80 nm.

[0035] As a preferred solution, in step A2, the microwave treatment conditions are: frequency 2 GHz, power 800 W, and treatment time 60 seconds.

[0036] The present invention also provides a transparent conductive oxide ITO film, which is prepared by the above preparation method.

[0037] The present invention also provides an application of a transparent conductive oxide ITO film, which includes applying the transparent conductive oxide ITO film to the preparation of a heterojunction solar cell to improve the electrical and optical properties of the heterojunction solar cell.

[0038] As a preferred solution, the application includes:

[0039] Preparation of heterojunction solar cells:

[0040] S1: cleaning the silicon wafer and then texturing it to form a texture layer on both sides of the silicon wafer, and further depositing an intrinsic amorphous silicon layer and a doped microcrystalline silicon layer on the texture layers on both sides, wherein the front side is an N-type doped microcrystalline silicon layer and the back side is a P-type doped microcrystalline silicon layer;

[0041] S2: Depositing the transparent conductive oxide ITO film on the surface of the doped microcrystalline silicon layer on the front and back sides of the silicon wafer processed in step S1;

[0042] S3: preparing electrodes on the transparent conductive oxide ITO film deposited in step S2, and finally completing the preparation of the heterojunction solar cell.

[0043] As a preferred solution, in step S1, the thickness of the intrinsic amorphous silicon layer is 3-15 nm, and the thickness of the doped microcrystalline layer is 10-50 nm.

[0044] As a preferred solution, in step S1, the thickness of the intrinsic amorphous silicon layer is 5 nm, and the thickness of the doped microcrystalline layer is 30 nm.

[0045] As a preferred solution, in step S3, the electrode is a silver paste electrode, and the silver paste electrode is fixed on the transparent conductive oxide ITO film by printing.

[0046] The following provides an embodiment combined with specific data to further describe the above technical solution of the present invention:

[0047] Embodiment 1:

[0048] This embodiment provides a method for preparing a transparent conductive oxide ITO film, comprising the following steps:

[0049] A1: Select a silicon wafer and deposit an ITO transparent conductive layer on the microcrystalline silicon layer on both sides of the silicon wafer; the conditions for depositing the ITO transparent conductive layer include: a silicon wafer temperature of 150° C., a tin oxide content of 6.5 wt % in the ITO film, and an ITO film deposition thickness of 75 nm.

[0050] A2: After the ITO transparent conductive layer of step A1 is prepared, the silicon wafer is placed in a microwave environment for microwave treatment. The microwave treatment conditions are: frequency 2 GHz, power range 750 W, and treatment time 45 seconds, so as to obtain a transparent conductive oxide ITO film.

[0051] This embodiment provides a transparent conductive oxide ITO film, which is prepared by the above preparation method.

[0052] This embodiment also provides an application of a transparent conductive oxide ITO film, which includes applying the transparent conductive oxide ITO film to the preparation of a heterojunction solar cell to improve the electrical and optical properties of the heterojunction solar cell.

[0053] The applications include:

[0054] Preparation of heterojunction solar cells:

[0055] S1: Cleaning and texturing the silicon wafer to form a texture layer on both sides of the silicon wafer, and further depositing an intrinsic amorphous silicon layer and a doped microcrystalline silicon layer on the texture layers on both sides, wherein the thickness of the intrinsic amorphous silicon layer is 5 nm, and the thickness of the doped microcrystalline layer is 30 nm, wherein the front side is an N-type doped microcrystalline silicon layer, and the back side is a P-type doped microcrystalline silicon layer;

[0056] S2: Depositing the transparent conductive oxide ITO film on the surface of the doped microcrystalline silicon layer on the front and back sides of the silicon wafer processed in step S1;

[0057] S3: preparing an electrode on the transparent conductive oxide ITO film deposited in step S2, and fixing the electrode on the transparent conductive oxide ITO film by printing a silver paste electrode, thereby finally completing the preparation of a heterojunction solar cell;

[0058] like Figure 1 , Figure 2 As shown, Figure 1 is a scanning electron microscope image of the ITO film in Example 1; Figure 2 The surface atomic force microscope morphology of the ITO film in Example 1.

[0059] Embodiment 2:

[0060] This embodiment provides a method for preparing a transparent conductive oxide ITO film, comprising the following steps:

[0061] A1: Select a silicon wafer and deposit an ITO transparent conductive layer on the microcrystalline silicon layer on both sides of the silicon wafer; the conditions for depositing the ITO transparent conductive layer include: silicon wafer temperature 100° C., tin oxide content in the ITO film 3wt%, and ITO film deposition thickness 50nm.

[0062] A2: After the ITO transparent conductive layer of step A1 is prepared, the silicon wafer is placed in a microwave environment for microwave treatment. The microwave treatment conditions are: frequency 1 GHz, power range 500 W, and treatment time 30 seconds, so as to obtain a transparent conductive oxide ITO film.

[0063] This embodiment provides a transparent conductive oxide ITO film, which is prepared by the above preparation method.

[0064] This embodiment also provides an application of a transparent conductive oxide ITO film, which includes applying the transparent conductive oxide ITO film to the preparation of a heterojunction solar cell to improve the electrical and optical properties of the heterojunction solar cell.

[0065] The applications include:

[0066] Preparation of heterojunction solar cells:

[0067] S1: Cleaning and texturing the silicon wafer to form a texture layer on both sides of the silicon wafer, and further depositing an intrinsic amorphous silicon layer and a doped microcrystalline silicon layer on the texture layers on both sides, wherein the thickness of the intrinsic amorphous silicon layer is 3 nm, and the thickness of the doped microcrystalline layer is 10 nm, wherein the front side is an N-type doped microcrystalline silicon layer, and the back side is a P-type doped microcrystalline silicon layer;

[0068] S2: Depositing the transparent conductive oxide ITO film on the surface of the doped microcrystalline silicon layer on the front and back sides of the silicon wafer processed in step S1;

[0069] S3: preparing an electrode on the transparent conductive oxide ITO film deposited in step S2, and fixing the electrode on the transparent conductive oxide ITO film by printing a silver paste electrode, thereby finally completing the preparation of a heterojunction solar cell.

[0070] Embodiment 3:

[0071] This embodiment provides a method for preparing a transparent conductive oxide ITO film, comprising the following steps:

[0072] A1: Select a silicon wafer and deposit an ITO transparent conductive layer on the microcrystalline silicon layer on both sides of the silicon wafer; the conditions for depositing the ITO transparent conductive layer include: silicon wafer temperature 200°C, tin oxide content in the ITO film 10wt%, and ITO film deposition thickness 100nm.

[0073] A2: After the ITO transparent conductive layer of step A1 is prepared, the silicon wafer is placed in a microwave environment for microwave treatment. The microwave treatment conditions are: frequency 3 GHz, power range 1200 W, and treatment time 60 seconds, so as to obtain a transparent conductive oxide ITO film.

[0074] This embodiment provides a transparent conductive oxide ITO film, which is prepared by the above preparation method.

[0075] This embodiment also provides an application of a transparent conductive oxide ITO film, which includes applying the transparent conductive oxide ITO film to the preparation of a heterojunction solar cell to improve the electrical and optical properties of the heterojunction solar cell.

[0076] The applications include:

[0077] Preparation of heterojunction solar cells:

[0078] S1: Cleaning and texturing a silicon wafer to form a velvet layer on both sides of the silicon wafer, and further depositing an intrinsic amorphous silicon layer and a doped microcrystalline silicon layer on the velvet layers on both sides, wherein the thickness of the intrinsic amorphous silicon layer is 15 nm, and the thickness of the doped microcrystalline layer is 50 nm, wherein the front side is an N-type doped microcrystalline silicon layer, and the back side is a P-type doped microcrystalline silicon layer;

[0079] S2: Depositing the transparent conductive oxide ITO film on the surface of the doped microcrystalline silicon layer on the front and back sides of the silicon wafer processed in step S1;

[0080] S3: preparing an electrode on the transparent conductive oxide ITO film deposited in step S2, and fixing the electrode on the transparent conductive oxide ITO film by printing a silver paste electrode, thereby finally completing the preparation of a heterojunction solar cell.

[0081] Moreover, the average grain size of the ITO film prepared in the above embodiments 1-3 is greater than 50nm, the average surface roughness of the film is greater than 10um, the average transmittance of the film in the visible light range is greater than 95%, and the average square resistance of the film is less than 100Ω / □. The photoelectric conversion efficiency of the prepared heterojunction solar cell is increased by more than 0.2%, which solves the problems existing in the background technology.

[0082] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0083] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0084] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a transparent conductive oxide ITO film, characterized in that: The following steps are involved: A1: Select a silicon wafer and deposit an ITO transparent conductive layer on the microcrystalline silicon layer on both sides of the silicon wafer; A2: After the ITO transparent conductive layer of step A1 is prepared, the silicon wafer is placed in a microwave environment for microwave treatment. The microwave treatment conditions are: frequency 1-3 GHz, power range 500-1200 W, and treatment time 30-100 seconds, so as to obtain a transparent conductive oxide ITO film.

2. The method for preparing a transparent conductive oxide ITO thin film according to claim 1, characterized in that: In the step A1, the conditions for depositing the ITO transparent conductive layer include: a silicon wafer temperature of 100-200° C., a tin oxide content of 3-10 wt % in the ITO film, and an ITO film deposition thickness of 50-100 nm.

3. The method for preparing the transparent conductive oxide ITO thin film according to claim 2, characterized in that: In the step A1, the conditions for depositing the ITO transparent conductive layer include: a silicon wafer temperature of 150° C., a tin oxide content of 5% in the ITO film, and an ITO film deposition thickness of 80 nm.

4. The method for preparing a transparent conductive oxide ITO thin film according to claim 1, characterized in that: In step A2, the microwave treatment conditions are: frequency 2 GHz, power 800 W, and treatment time 60 seconds.

5. A transparent conductive oxide ITO film, characterized in that: The ITO film is prepared by any one of the preparation methods of claims 1-4.

6. An application of a transparent conductive oxide ITO film, characterized in that: The application includes applying the transparent conductive oxide ITO film described in claim 5 to the preparation of heterojunction solar cells to improve the electrical and optical properties of the heterojunction solar cells.

7. The use of the transparent conductive oxide ITO film according to claim 6, characterized in that: The applications include: Preparation of heterojunction solar cells: S1: cleaning the silicon wafer and then texturing it to form a texture layer on both sides of the silicon wafer, and further depositing an intrinsic amorphous silicon layer and a doped microcrystalline silicon layer on the texture layers on both sides, wherein the front side is an N-type doped microcrystalline silicon layer and the back side is a P-type doped microcrystalline silicon layer; S2: Depositing the transparent conductive oxide ITO film on the surface of the doped microcrystalline silicon layer on the front and back sides of the silicon wafer processed in step S1; S3: preparing electrodes on the transparent conductive oxide ITO film deposited in step S2, and finally completing the preparation of the heterojunction solar cell.

8. The use of the transparent conductive oxide ITO film according to claim 7, characterized in that: In the step S1, the thickness of the intrinsic amorphous silicon layer is 3-15 nm, and the thickness of the doped microcrystalline layer is 10-50 nm.

9. The use of the transparent conductive oxide ITO film according to claim 8, characterized in that: In the step S1, the thickness of the intrinsic amorphous silicon layer is 5 nm, and the thickness of the doped microcrystalline layer is 30 nm.

10. The use of the transparent conductive oxide ITO film according to claim 7, characterized in that: In the step S3, the electrode is a silver paste electrode, and the silver paste electrode is fixed on the transparent conductive oxide ITO film by printing.

Images