Cigs absorber layer, copper indium gallium selenide thin film solar cell and preparation method

Abstract

The application provides a CIGS absorption layer, a copper indium gallium selenium thin film solar cell and a preparation method. High-energy plasma is generated by ionizing inert gas, a CIGS target is bombarded, a CIGS thin film is prepared on a pre-prepared substrate, and post annealing is performed in a selenium-containing atmosphere, so that the CIGS absorption layer with uniform composition and smooth surface is produced. Then, a KF-doped CIGS:KF target is used for sputtering, so that the effect of alkali metal doping treatment is achieved. The CIGS thin film prepared by the magnetron sputtering method has uniform composition and smooth surface. Meanwhile, the incorporation of alkali metal further improves the open-circuit voltage and the fill factor of the CIGS cell, effectively improves the performance parameters of the cell, and greatly improves the photoelectric conversion efficiency of the cell.

Description

Technical Field

[0001] This application relates to the field of thin-film solar cell technology, and in particular to a CIGS absorber layer, a copper indium gallium selenide thin-film solar cell, and a method for preparing the same. Background Technology

[0002] CIGS thin-film solar cells possess high efficiency and hold immense potential in the photovoltaic market. A three-step co-evaporation method using copper, indium, gallium, and selenium to prepare the CIGS absorber layer allows for precise control of sample composition. However, the fabrication of a large-area, uniform linear evaporation source is inherently challenging, and accurately controlling the evaporation rates of the four different elements requires highly precise equipment. These issues hinder the fabrication of large-area CIGS cells. Furthermore, selenium (Se) vapor is highly corrosive to stainless steel. Over prolonged use, Se condenses in various locations and forms Fe-Se binary compounds on the inner wall of the chamber. These Fe-Se compounds can peel off during equipment use and may fall onto the film surface, leading to a reduction in film quality. Therefore, the use of Se vapor also makes it difficult to achieve continuous production over extended periods using the co-evaporation process for CIGS cells. Summary of the Invention

[0003] Therefore, it is necessary to provide a high-quality CIGS absorber layer, a copper indium gallium selenide thin-film solar cell, and a preparation method for addressing the technical problem of the low quality of the main absorber layer in current CIGS solar cells.

[0004] To solve the above problems, this application adopts the following technical solution: One objective of this application is to provide a method for preparing a CIGS absorber layer, comprising the following steps: The substrate with the deposited Mo back electrode is placed in a high vacuum chamber, and the high vacuum chamber is heated to 180-200°C and held for 30-60 minutes. High-energy plasma is generated by ionizing inert gas in the high vacuum chamber and bombards the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate. The high vacuum chamber is cooled to 80-100°C, and the CIGS target is replaced with a CIGS:KF target. High-energy plasma is generated in the high vacuum chamber by ionizing inert gas and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF film on the surface of the CIGS film. After the CIGS:KF target sputtering is completed, the temperature of the high vacuum chamber is raised to 280-300℃, and annealing is performed under vacuum conditions to allow alkali metal elements to diffuse to the surface of the CIGS thin film to form a K-In-Se layer.

[0005] In some embodiments, in the step of placing a substrate with a deposited Mo back electrode in a high vacuum chamber and heating the high vacuum chamber to 180-200°C and holding it at that temperature for 30-60 minutes, Mo is deposited on the substrate as a back electrode using DC radio frequency magnetron sputtering. The substrate can be soda-lime glass or a flexible substrate, and the flexible substrate includes titanium foil or stainless steel foil.

[0006] In some embodiments, the step of generating high-energy plasma by ionizing inert gas within the high-vacuum chamber and bombarding the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate specifically includes the following steps: An inert gas is introduced into the high vacuum chamber, and an external electric field is generated by turning on the intermediate frequency power supply. This ionizes the inert gas to produce positive ions and new electrons, which bombard the target surface with high energy, causing the target material to be sputtered and depositing a CIGS thin film on the surface of the substrate. The flow rate of the argon gas is 80-100°C, the voltage of the intermediate frequency power supply is 180-220V, and the sputtering power is 345-350W.

[0007] In some embodiments, the following steps are also included: During the sputtering process, the substrate moves at a constant speed on the surface of the CIGS target to deposit a uniform CIGS film on the surface of the substrate. The Ar gas flow rate during sputtering is 200-210 sccm, the gas pressure in the high vacuum chamber is 0.2-0.3 Pa, the constant speed is 0.1-0.15 m / s, and the substrate passes over the CIGS target surface 8-10 times.

[0008] In some embodiments, the steps of cooling the high-vacuum cavity to 80-100°C, replacing the CIGS target with a CIGS:KF target, generating high-energy plasma in the high-vacuum cavity by ionizing inert gas and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF thin film on the surface of the CIGS thin film specifically include the following steps: The high-vacuum chamber is cooled to 80-100℃, the CIGS target is replaced with a CIGS:KF target, inert gas is introduced into the high-vacuum chamber, and an external electric field is generated by turning on the intermediate frequency power supply. This causes the inert gas to ionize and generate positive ions and new electrons to bombard the target surface with high energy, causing the CIGS:KF target to sputter and deposit a CIGS:KF film on the surface of the CIGS film. The inert gas flow rate is 390-400 sccm, the voltage applied to the intermediate frequency power supply is between 200V and 300V, the sputtering power is 140-155W, and the working pressure is 0.2-0.3Pa.

[0009] In some embodiments, after sputtering, the temperature of the high vacuum chamber is raised to 280-300°C, and annealing is performed under vacuum conditions to allow alkali metal elements to diffuse onto the surface of the CIGS thin film to form a K-In-Se layer. The annealing temperature is 280-300°C.

[0010] A second objective of this application is to provide a CIGS absorber layer, which is prepared by the aforementioned preparation method.

[0011] A third objective of this application is to provide a method for preparing a copper indium gallium selenide thin-film solar cell, comprising the following steps: Provide a substrate; Mo back electrode is deposited on the substrate; A CIGS absorber layer is deposited on the Mo back electrode; A cadmium sulfide (CdS), intrinsic zinc oxide (I-ZnO), and aluminum-doped zinc oxide (AZO) thin films are sequentially prepared on the surface of the CIGS absorber layer. The grid is then fabricated using electron beam evaporation to obtain the CIGS solar cell. The deposition of the CIGS absorber layer on the Mo back electrode specifically includes the following steps: The substrate with the deposited Mo back electrode is placed in a high vacuum chamber, and the high vacuum chamber is heated to 180-200°C and held for 30-60 minutes. High-energy plasma is generated by ionizing inert gas in the high vacuum chamber and bombards the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate. The high vacuum chamber is cooled to 80-100°C, and the CIGS target is replaced with a CIGS:KF target. High-energy plasma is generated in the high vacuum chamber by ionizing inert gas and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF film on the surface of the CIGS film. After the CIGS:KF target sputtering is completed, the temperature of the high vacuum chamber is raised to 280-300℃, and annealing is performed under vacuum conditions to allow alkali metal elements to diffuse to the surface of the CIGS thin film to form a K-In-Se layer.

[0012] A third objective of this application is to provide a copper indium gallium selenide (CIGS) thin-film solar cell, which is prepared by the aforementioned method for preparing a CIGS thin-film solar cell.

[0013] The present application adopts the above technical solution, and its beneficial effects are as follows: The CIGS absorber layer, copper indium gallium selenide (CIGS) thin-film solar cell, and their fabrication method provided in this application utilize a high-energy plasma generated by ionizing an inert gas to bombard a CIGS target, thereby preparing a CIGS thin film on a pre-prepared substrate. Post-annealing in a selenium-containing atmosphere produces a CIGS absorber layer with uniform composition and a smooth surface. Subsequently, a KF-doped CIGS:KF target is used for sputtering to achieve alkali metal doping. The CIGS thin film prepared by magnetron sputtering exhibits uniform composition and a smooth surface. Furthermore, the incorporation of alkali metals further improves the open-circuit voltage and fill factor of the CIGS cell, effectively enhancing its performance parameters and significantly increasing its photoelectric conversion efficiency. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart illustrating the steps of a method for preparing a CIGS absorber layer according to an embodiment of the present invention.

[0016] Figure 2 This is a flowchart illustrating the steps of a method for fabricating a copper indium gallium selenide (CIGS) thin-film solar cell according to an embodiment of the present invention.

[0017] Figure 3 A comparison of the surface morphology of CIGS prepared by vapor deposition and sputtering methods according to an embodiment of the present invention.

[0018] Figure 4 A comparison of performance parameters of CIGS prepared by vapor deposition and sputtering methods according to an embodiment of the present invention. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified. To make the objectives, technical solutions, and advantages of this application clearer, the following describes this application in further detail, taking the multifunctional detection of atherosclerosis in blood vessels as an example, in conjunction with the accompanying drawings and embodiments.

[0020] Please see Figure 1 The present application provides a flowchart of a method for preparing an absorption layer, which includes steps S110 to S140. The implementation of each step is described in detail below.

[0021] Step S110: Place the substrate with the deposited Mo back electrode in a high vacuum chamber, and heat the high vacuum chamber to 180-200°C, holding it at that temperature for 30-60 minutes. The temperature and time used in this step ensure that any moisture that may be present on the sample surface and in the chamber is removed without affecting the film growth.

[0022] In this embodiment, the substrate may be soda-lime glass or a flexible substrate, wherein the flexible substrate includes titanium foil or stainless steel foil.

[0023] It is understandable that before depositing the Mo back electrode on the substrate, a step of cleaning the substrate surface is included to remove surface contaminants and dust. After cleaning, the substrate is liquid-sealed with deionized water to avoid contamination.

[0024] In this embodiment, a Mo metal thin film is deposited on the substrate using DC radio frequency magnetron sputtering as an impurity element blocking layer and a back electrode, and good contact between the Mo layer and the substrate is achieved.

[0025] Step S120: High-energy plasma is generated in the high vacuum chamber by ionizing inert gas and bombarding the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate.

[0026] In this embodiment, the step of generating high-energy plasma by ionizing inert gas in the high-vacuum cavity and bombarding the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate specifically includes the following steps: Inert gas is introduced into the high-vacuum chamber, and an external electric field is generated by turning on the intermediate frequency power supply. This ionizes the inert gas, producing positive ions and new electrons that bombard the target surface with high energy, causing sputtering of the target material and deposition of a CIGS thin film on the substrate surface. The inert gas flow rate is 390-400 sccm, the intermediate frequency power supply voltage is 180-220V, and the sputtering power is 345-350W. These parameters were determined through repeated experiments, allowing for the cleaning of target surface residues and the purification of gas pipelines, while also ensuring greater stability of the intermediate frequency power supply during sputtering.

[0027] Furthermore, inert gases include argon.

[0028] It is understood that this embodiment pre-sputters the target material to clean impurities on the target surface and stabilize the power.

[0029] Furthermore, during the sputtering process, the substrate moves at a constant speed on the surface of the CIGS target to deposit a uniform CIGS thin film on the substrate surface. The inert gas flow rate during sputtering is 200-210 sccm, the gas pressure in the high-vacuum chamber is 0.2-0.3 Pa, the constant speed is 0.1-0.15 m / s, and the substrate passes over the CIGS target surface 8-10 times. These parameters, determined through repeated experiments, ensure a stable sputtering rate and prevent damage to the film surface. After the sample holder passes over the target 8-10 times, a CIGS thin film with a thickness of 2-2.3 μm can be prepared on the substrate surface.

[0030] Step S130: Cool the high vacuum chamber to 80-100°C, replace the CIGS target with a CIGS:KF target, generate high-energy plasma in the high vacuum chamber by ionizing inert gas and bombard the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF thin film on the surface of the CIGS thin film.

[0031] In this embodiment, the steps of cooling the high-vacuum cavity to 80-100°C, replacing the CIGS target with a CIGS:KF target, generating high-energy plasma in the high-vacuum cavity by ionizing inert gas, and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF thin film on the surface of the CIGS thin film specifically include the following steps: The high-vacuum chamber is cooled to 80-100℃, and the CIGS target is replaced with a CIGS:KF target. Inert gas is introduced into the high-vacuum chamber, and an external electric field is generated by turning on the intermediate frequency power supply. Ar atoms are ionized to produce Ar positive ions and new electrons, which bombard the target surface with high energy, causing sputtering of the CIGS:KF target and deposition of a CIGS:KF film on the surface of the CIGS film. The Ar gas flow rate is 390-400 sccm, the voltage of the intermediate frequency power supply is between 200V and 300V, the sputtering power is 140-155W, and the working pressure is 0.2-0.3Pa. After repeated experiments, it was determined that the above parameters can ensure a stable sputtering rate, avoid damage to the film surface, and have no significant impact on the film composition, thereby depositing a thin CIGS:KF layer on the surface of the CIGS film to achieve the effect of alkali metal deposition.

[0032] Step S140: After sputtering, the temperature of the high vacuum chamber is raised to 280-300℃, and annealing is performed under vacuum conditions to allow alkali metal elements to diffuse to the surface of the CIGS thin film to form a K-In-Se layer.

[0033] In this embodiment, the step of raising the temperature of the high-vacuum chamber to 280-300°C after sputtering and performing annealing under vacuum conditions to allow alkali metal elements to diffuse onto the CIGS film surface to form a K-In-Se layer specifically includes the following steps: After sputtering the CIGS film surface 8-10 times, the high vacuum chamber temperature is raised to 280-300℃, and annealing is performed at 250-300℃ under vacuum conditions. Annealing at this temperature allows the alkali metal elements on the CIGS film surface to diffuse and form a K-In-Se layer on the absorber layer surface, while avoiding Se loss due to excessively high temperatures.

[0034] It is understandable that annealing allows KF to diffuse sufficiently on the sample surface.

[0035] The CIGS absorber layer prepared in the above embodiments of this application is produced by bombarding a CIGS target with high-energy plasma generated by ionizing an inert gas to form a CIGS thin film on a pre-prepared substrate. Post-annealing in a selenium-containing atmosphere produces a CIGS absorber layer with uniform composition and a smooth surface. Subsequently, a KF-doped CIGS:KF target is used for sputtering to achieve alkali metal doping. The CIGS thin film prepared by magnetron sputtering has uniform composition and a smooth surface.

[0036] Please see Figure 2 The present application provides a flowchart of a method for fabricating a copper indium gallium selenide thin-film solar cell, including steps S210 to S240. The implementation of each step is described in detail below.

[0037] Step S210: Provide a substrate.

[0038] In this embodiment, a wide range of substrates can be selected, including soda-lime glass or flexible substrates such as titanium foil or stainless steel foil.

[0039] Step S220: Deposit a Mo back electrode on the substrate.

[0040] In this embodiment, a Mo metal thin film is deposited on the substrate using DC radio frequency magnetron sputtering as an impurity element blocking layer and a back electrode, and good contact between the Mo layer and the substrate is achieved.

[0041] It is understandable that before depositing the Mo back electrode on the substrate, a step of cleaning the substrate surface is included to remove surface contaminants and dust. After cleaning, the substrate is liquid-sealed with deionized water to avoid contamination.

[0042] Step S230: Deposit a CIGS absorber layer on the Mo back electrode.

[0043] In this embodiment, the deposition of the CIGS absorber layer on the Mo back electrode can be referred to steps S110 to S140 provided in the above embodiments, and will not be repeated here.

[0044] Step S240: Cadmium sulfide (CdS), intrinsic zinc oxide (I-ZnO), and aluminum-doped zinc oxide (AZO) films are sequentially prepared on the surface of the CIGS absorber layer, and then the grid is prepared by electron beam evaporation to obtain a CIGS solar cell.

[0045] Specifically, CdS is prepared as a buffer layer and a PN junction forming layer on the surface of the CIGS absorber layer. Intrinsic zinc oxide (I-ZnO) and aluminum-doped zinc oxide (AZO) films are prepared on the surface using magnetron sputtering. Then, the gate is prepared by electron beam evaporation to obtain a complete CIGS solar cell module.

[0046] The copper indium gallium selenide (CIGS) thin-film solar cell provided in the above embodiments of this application utilizes high-energy plasma generated by ionizing inert gas to bombard a CIGS target, thereby preparing a CIGS thin film on a pre-prepared substrate. Post-annealing in a selenium-containing atmosphere produces a CIGS absorber layer with uniform composition and a smooth surface. Subsequently, a KF-doped CIGS:KF target is used for sputtering to achieve alkali metal doping. The CIGS thin film prepared by magnetron sputtering exhibits uniform composition and a smooth surface. Furthermore, the incorporation of alkali metals further improves the open-circuit voltage and fill factor of the CIGS cell, effectively enhancing its performance parameters and significantly increasing its photoelectric conversion efficiency.

[0047] The technical solutions described above in this application will be explained in detail below with reference to specific embodiments.

[0048] Example 1 1) Clean the substrate surface using a cleaning machine, for a total of 4 cleanings, each lasting 1 hour and 20 minutes. The substrate orientation was reversed between each cleaning cycle to remove surface contaminants and dust. After cleaning, the substrate was liquid-sealed with deionized water to prevent contamination. 2) Mo metal thin films are deposited on the substrate using DC radio frequency magnetron sputtering as impurity element blocking layers and back electrodes, and good contact between the Mo layer and the substrate is achieved. 3) Place the substrate on the sample holder and send it into the intermediate frequency magnetron sputtering chamber. Heat the chamber to 200°C and hold for 30 minutes to evaporate the water vapor on the sample surface. Inert gas is introduced into the chamber, and the 220V intermediate frequency power supply is turned on to generate an external electric field, which causes argon atoms to ionize and generate Ar positive ions and new electrons to bombard the target surface with high energy. This pre-sputtering of the target material removes impurities from the target surface. The argon gas flow rate is 400 sccm and the sputtering power is 350 W. 4) After the target power stabilizes, turn on the sample holder drive device. During the growth process, the flow rate of Ar gas is 210 sccm, and the gas pressure in the growth chamber is controlled at 0.3 Pa. The sample holder speed is set to 0.1 m / s. It needs to pass over the target surface 8 times to ensure that the sample moves on the target surface at a suitable speed to obtain a uniform and high-quality film. 5) Cool the high-vacuum chamber to 100°C, replace the target material with CIGS:KF, introduce Ar gas at a flow rate of 400 sccm, apply a voltage of 300V to the intermediate frequency power supply, set the power to 150W, and the working pressure to 0.3Pa. After sputtering, raise the chamber temperature to 300°C and anneal under vacuum conditions to allow the alkali metal elements to fully diffuse onto the CIGS film surface to form a K-In-Se layer. Then, remove the sample.

[0049] 6) After completing the surface modification treatment, CdS was prepared on the surface of the CIGS film as a buffer layer and a PN junction forming layer. Using CdSO4 as the cadmium source, thiourea as the sulfur precursor, and NH3•H2O as the buffer solution, a CdS film was prepared on the surface of the CIGS film using a water bath method. After the reaction was completed, it was annealed at 300℃.

[0050] 7) Intrinsic zinc oxide (I-ZnO) and aluminum-doped zinc oxide (AZO) films were prepared on the surface using magnetron sputtering. For I-ZnO, the reactant gases were Ar and O2, with an Ar flow rate of 200 sccm and an O2 flow rate of 2 sccm. The initial sputtering power was 120 W, subsequently increased to 220 W. For AZO, the reactant gases were Ar and H2, with an Ar flow rate of 200 sccm and an H2 flow rate of 2 sccm. The sputtering temperature was 160℃ for 15 min, and the sputtering power was 750 W.

[0051] 8) The gate electrode was fabricated using electron beam evaporation. The target materials used were Ni and Al, with a Ni layer thickness of 1500 Å and an Al layer thickness of 100000 Å. The gate electrode was obtained, completing the CIGS solar cell fabrication process.

[0052] Please see Figure 3 The table compares the surface morphology of CIGS prepared by sputtering in Example 1 of this application with that prepared by vapor deposition in the prior art, wherein: Figure 3 (a) shows a CIGS surface prepared using vapor deposition, and (b) shows a CIGS surface prepared using sputtering. Figure 3 As can be seen, CIGS prepared by sputtering has a smoother surface and larger grains, indicating a better crystallization effect.

[0053] Please see Figure 4 This is a comparison of the performance parameters of CIGS prepared by the sputtering method provided in Example 1 of this application and the existing technology using the vapor deposition method. Figure 4 As can be seen from this, CIGS prepared by sputtering has a higher open-circuit voltage (V) after all process steps are completed. oc ), current density (J) sc With a fill factor (FF), its overall performance parameters are superior to those of CIGS by vapor deposition, resulting in higher photoelectric conversion efficiency.

[0054] Example 2 1) Clean the substrate surface using a cleaning machine, for a total of 4 cleanings, each lasting 1 hour and 20 minutes. The substrate orientation was reversed between each cleaning cycle to remove surface contaminants and dust. After cleaning, the substrate was liquid-sealed with deionized water to prevent contamination. 2) Mo metal thin films are deposited on the substrate using DC radio frequency magnetron sputtering as impurity element blocking layers and back electrodes, and good contact between the Mo layer and the substrate is achieved. 3) Place the substrate on the sample holder and send it into the intermediate frequency magnetron sputtering chamber. Heat the chamber to 180°C and hold for 30 minutes to evaporate the water vapor on the sample surface. Introduce argon gas into the chamber and turn on the 180V intermediate frequency power supply to generate an external electric field, causing argon atoms to ionize and produce Ar positive ions and new electrons to bombard the target surface with high energy. This pre-sputters the target material to remove impurities from the target surface. The argon gas flow rate is 390 sccm and the sputtering power is 345 W. 4) After the target power stabilizes, turn on the sample holder drive device. During the growth process, the flow rate of Ar gas is 200 sccm, and the gas pressure in the growth chamber is controlled at 0.2 Pa. The sample holder speed is set to 0.15 m / s. It needs to pass over the target surface 10 times to ensure that the sample moves on the target surface at a suitable speed to obtain a uniform and high-quality film. 5) Cool the high-vacuum chamber to 80°C, replace the target material with CIGS:KF, introduce Ar gas at a flow rate of 390 sccm, apply a voltage of 200V to the intermediate frequency power supply, set the power to 155W, and the working pressure to 0.3Pa. After sputtering, raise the chamber temperature to 280°C and anneal under vacuum conditions to allow the alkali metal elements to fully diffuse onto the CIGS film surface to form a K-In-Se layer. Then, remove the sample.

[0055] 6) After completing the surface modification treatment, CdS was prepared on the surface of the CIGS film as a buffer layer and a PN junction forming layer. Using CdSO4 as the cadmium source, thiourea as the sulfur precursor, and NH3•H2O as the buffer solution, a CdS film was prepared on the surface of the CIGS film using a water bath method. After the reaction was completed, it was annealed at 280℃.

[0056] 7) Intrinsic zinc oxide (I-ZnO) and aluminum-doped zinc oxide (AZO) films were prepared on the surface using magnetron sputtering. For I-ZnO, the reactant gases were Ar and O2, with an Ar flow rate of 200 sccm and an O2 flow rate of 2 sccm. The initial sputtering power was 120 W, subsequently increased to 220 W. For AZO, the reactant gases were Ar and H2, with an Ar flow rate of 200 sccm and an H2 flow rate of 2 sccm. The sputtering temperature was 160℃ for 15 min, and the sputtering power was 750 W.

[0057] 8) The gate electrode was fabricated using electron beam evaporation. The target materials used were Ni and Al, with a Ni layer thickness of 1500 Å and an Al layer thickness of 100000 Å. The gate electrode was obtained, completing the CIGS solar cell fabrication process.

[0058] Example 3 1) Clean the substrate surface using a cleaning machine, for a total of 4 cleanings, each lasting 1 hour and 20 minutes. The substrate orientation was reversed between each cleaning cycle to remove surface contaminants and dust. After cleaning, the substrate was liquid-sealed with deionized water to prevent contamination. 2) Mo metal thin films are deposited on the substrate using DC radio frequency magnetron sputtering as impurity element blocking layers and back electrodes, and good contact between the Mo layer and the substrate is achieved. 3) Place the substrate on the sample holder and send it into the intermediate frequency magnetron sputtering chamber. Heat the chamber to 190°C and hold for 50 minutes to evaporate the water vapor on the sample surface. Introduce argon gas into the chamber and turn on the 200V intermediate frequency power supply to generate an external electric field, causing argon atoms to ionize and produce Ar positive ions and new electrons to bombard the target surface with high energy. This pre-sputters the target material to remove impurities from the target surface. The argon gas flow rate is 395 sccm and the sputtering power is 345 W. 4) After the target power stabilizes, turn on the sample holder drive device. During the growth process, the flow rate of Ar gas is 205 sccm, and the gas pressure in the growth chamber is controlled at 0.2 Pa. The sample holder speed is set to 0.12 m / s. It needs to pass over the target surface 9 times to ensure that the sample moves on the target surface at an appropriate speed to obtain a uniform and high-quality film. 5) Cool the high-vacuum chamber to 90°C, replace the target material with CIGS:KF, introduce Ar gas at a flow rate of 395 sccm, apply a voltage of 250V to the intermediate frequency power supply, set the power to 150W, and the working pressure to 0.3Pa. After sputtering, raise the chamber temperature to 290°C and anneal under vacuum conditions to allow the alkali metal elements to fully diffuse onto the CIGS film surface to form a K-In-Se layer. Then, remove the sample.

[0059] 6) After completing the surface modification treatment, CdS was prepared on the surface of the CIGS film as a buffer layer and a PN junction forming layer. Using CdSO4 as the cadmium source, thiourea as the sulfur precursor, and NH3•H2O as the buffer solution, a CdS film was prepared on the surface of the CIGS film using a water bath method. After the reaction was completed, it was annealed at 290℃.

[0060] 7) Intrinsic zinc oxide (I-ZnO) and aluminum-doped zinc oxide (AZO) films were prepared on the surface using magnetron sputtering. For I-ZnO, the reactant gases were Ar and O2, with an Ar flow rate of 200 sccm and an O2 flow rate of 2 sccm. The initial sputtering power was 120 W, subsequently increased to 220 W. For AZO, the reactant gases were Ar and H2, with an Ar flow rate of 200 sccm and an H2 flow rate of 2 sccm. The sputtering temperature was 160℃ for 15 min, and the sputtering power was 750 W.

[0061] 8) The gate electrode was fabricated using electron beam evaporation. The target materials used were Ni and Al, with a Ni layer thickness of 1500 Å and an Al layer thickness of 100000 Å. The gate electrode was obtained, completing the CIGS solar cell fabrication process.

[0062] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A method for preparing a CIGS absorber layer, characterized in that, Includes the following steps: The substrate with the deposited Mo back electrode is placed in a high vacuum chamber, and the high vacuum chamber is heated to 180-200°C and held for 30-60 minutes. High-energy plasma is generated by ionizing inert gas in the high vacuum chamber and bombards the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate. The high vacuum chamber is cooled to 80-100°C, and the CIGS target is replaced with a CIGS:KF target. High-energy plasma is generated in the high vacuum chamber by ionizing inert gas and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF film on the surface of the CIGS film. After the CIGS:KF target sputtering is completed, the temperature of the high vacuum chamber is raised to 280-300℃, and annealing is performed under vacuum conditions to allow alkali metal elements to diffuse to the surface of the CIGS thin film to form a K-In-Se layer.

2. The method for preparing the CIGS absorber layer as described in claim 1, characterized in that, In the step of placing a substrate with a deposited Mo back electrode in a high vacuum chamber and heating the high vacuum chamber to 180-200°C and holding it at that temperature for 30-60 minutes, Mo is deposited on the substrate as a back electrode using DC radio frequency magnetron sputtering. The substrate is made of soda-lime glass or a flexible substrate, and the flexible substrate includes titanium foil or stainless steel foil.

3. The method for preparing the CIGS absorber layer as described in claim 1, characterized in that, The step of generating high-energy plasma by ionizing inert gas in the high-vacuum chamber and bombarding the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate specifically includes the following steps: An inert gas is introduced into the high vacuum chamber, and an external electric field is generated by turning on the intermediate frequency power supply. This ionizes the inert gas to produce positive ions and new electrons, which bombard the target surface with high energy, causing the target material to be sputtered and depositing a CIGS thin film on the surface of the substrate. The inert gas flow rate is 390-400 sccm, the intermediate frequency power supply voltage is 180-220V, and the sputtering power is 345-350W.

4. The method for preparing the CIGS absorber layer as described in claim 3, characterized in that, It also includes the following steps: During the sputtering process, the substrate moves at a constant speed on the surface of the CIGS target to deposit a uniform CIGS film on the surface of the substrate. The inert gas flow rate during sputtering is 200-210 sccm, the gas pressure in the high vacuum chamber is 0.2-0.3 Pa, the constant speed is 0.1-0.15 m / s, and the substrate passes over the CIGS target surface 8-10 times.

5. The method for preparing the CIGS absorber layer as described in claim 1, characterized in that, The steps of cooling the high-vacuum cavity to 80-100°C, replacing the CIGS target with a CIGS:KF target, generating high-energy plasma in the high-vacuum cavity by ionizing inert gas, and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF thin film on the surface of the CIGS thin film specifically include the following steps: The high-vacuum chamber is cooled to 80-100℃, the CIGS target is replaced with a CIGS:KF target, inert gas is introduced into the high-vacuum chamber, and an external electric field is generated by turning on the intermediate frequency power supply. This causes the inert gas to ionize and generate positive ions and new electrons to bombard the target surface with high energy, causing the CIGS:KF target to sputter and deposit a CIGS:KF film on the surface of the CIGS film. The inert gas flow rate is 390-400 sccm, the voltage applied to the intermediate frequency power supply is between 200V and 300V, the sputtering power is 140-155W, and the working pressure is 0.2-0.3Pa.

6. The method for preparing the CIGS absorber layer as described in claim 1, characterized in that, The step of raising the temperature of the high-vacuum chamber to 280-300°C after sputtering and performing annealing under vacuum conditions to allow alkali metal elements to diffuse onto the surface of the CIGS thin film to form a K-In-Se layer specifically includes the following steps: After sputtering the CIGS film surface for 8-10 times, the sputtering is completed. The temperature of the high vacuum chamber is raised to 280-300℃, and annealing is performed at 250-300℃ under vacuum conditions to allow alkali metal elements to diffuse to the CIGS film surface and form a K-In-Se layer.

7. A CIGS absorber layer, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. A method for preparing a copper indium gallium selenide thin-film solar cell, characterized in that, Includes the following steps: Provide a substrate; Mo back electrode is deposited on the substrate; A CIGS absorber layer is deposited on the Mo back electrode; A cadmium sulfide (CdS), intrinsic zinc oxide (I-ZnO), and aluminum-doped zinc oxide (AZO) thin films are sequentially prepared on the surface of the CIGS absorber layer. The grid is then fabricated using electron beam evaporation to obtain the CIGS solar cell. The deposition of the CIGS absorber layer on the Mo back electrode specifically includes the following steps: The substrate with the deposited Mo back electrode is placed in a high vacuum chamber, and the high vacuum chamber is heated to 180-200°C and held for 30-60 minutes. High-energy plasma is generated by ionizing inert gas in the high vacuum chamber and bombards the CIGS target to sputter the CIGS target and deposit a CIGS thin film on the surface of the substrate. The high vacuum chamber is cooled to 80-100°C, and the CIGS target is replaced with a CIGS:KF target. High-energy plasma is generated in the high vacuum chamber by ionizing inert gas and bombarding the CIGS:KF target to sputter the CIGS:KF target and deposit a CIGS:KF film on the surface of the CIGS film. After the CIGS:KF target sputtering is completed, the temperature of the high vacuum chamber is raised to 280-300℃, and annealing is performed under vacuum conditions to allow alkali metal elements to diffuse to the surface of the CIGS thin film to form a K-In-Se layer.

9. A copper indium gallium selenide thin-film solar cell, characterized in that, It is prepared by the method for preparing copper indium gallium selenide thin-film solar cells according to claim 8.

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