Method for regulating and controlling alkali metal distribution of heterojunction interface of copper-based thin film solar cell

Abstract

The invention provides a method for regulating and controlling alkali metal distribution of a heterojunction interface of a copper-based thin film solar cell. The method comprises the following steps: depositing a lithium-doped copper-zinc-tin-sulfur precursor thin film on a back electrode; preparing a lithium-doped P-type copper-zinc-tin-sulfur-selenium thin film through high-temperature selenylation annealing, and promoting alkali metal elements in the glass substrate to diffuse to the copper-zinc-tin-sulfur-selenium thin film and realize doping through a selenylation annealing process; depositing a buffer layer on the CZTSSe thin film; a window layer and a transparent conductive layer are deposited on the surface of the buffer layer at low temperature, and alkali metal elements are driven to diffuse towards a heterojunction interface through low-temperature annealing treatment. According to the method provided by the invention, through a three-stage process system of doping design of the P-type absorption layer, high-temperature selenylation synergistic diffusion and low-temperature interface reconstruction, alkali metal content regulation and control of alkali metal elements on a CZTSSe / CdS heterojunction interface are realized, and the randomness limitation of spontaneous doping of a traditional soda-lime glass substrate is broken through. The invention also provides a solar cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and specifically relates to a method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell; more specifically, relates to a method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell and a solar cell. Background Art

[0002] Copper zinc tin sulfur selenide (CZTSSe) has attracted widespread attention in the photovoltaic field in recent years due to its abundant reserves, low cost, and environmentally friendly nature. As a derivative of copper indium gallium selenide (CIGS), CZTSSe belongs to the same family of direct-bandgap semiconductors. Furthermore, CZTSSe has an extremely high light absorption coefficient. When used as a photovoltaic absorber layer, a thickness of only a few microns is required to fabricate low-cost, large-area, and highly efficient solar cell devices.

[0003] In copper-based thin-film solar cells, the introduction of alkali metal elements is a key strategy for improving device performance. A core limitation of current mainstream doping methods lies in the inability to precisely control the alkali metal doping concentration. Overdoping has been shown to significantly degrade device performance. Therefore, developing a simple and controllable method for regulating the alkali metal distribution at heterojunction interfaces is crucial for overcoming current performance bottlenecks. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and a battery for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell, aiming to provide a simple and controllable way to regulate the distribution of alkali metals at the heterojunction interface.

[0005] To achieve the above-mentioned object, the technical solution adopted by the present invention is: providing a method for regulating the distribution of alkali metals at the heterojunction interface of copper-based thin-film solar cells, comprising the following steps: depositing a lithium-doped copper-zinc-tin-sulfur precursor film on a back electrode; preparing a lithium-doped P-type copper-zinc-tin-sulfur-selenium thin film by high-temperature selenization annealing, wherein the selenization annealing process promotes the diffusion of alkali metal elements in the glass substrate into the copper-zinc-tin-sulfur-selenium thin film and achieves doping; depositing a buffer layer on the copper-zinc-tin-sulfur-selenium thin film; and depositing a window layer and a transparent conductive layer on the surface of the buffer layer by low-temperature deposition, wherein the low-temperature annealing treatment drives the diffusion of alkali metal elements to the heterojunction interface.

[0006] Preferably, the depositing of a lithium-doped copper-zinc-tin-sulfur precursor film on the back electrode includes: dissolving copper acetate, stannous chloride dihydrate, zinc chloride, thiourea, lithium chloride and silver chloride in N,N-dimethylformamide in sequence to prepare a precursor solution, wherein the molar ratio of the metal elements in the precursor solution satisfies: Cu / (Zn+Sn)=0.6~0.75, Zn / Sn=1.0~1.5, Cu+Sn+Zn / S=1~0.9, Ag / (Cu+Ag)=0.05~0.10; Li / (Li+Cu)=0.01~0.20.

[0007] Preferably, the preparation of the lithium-doped P-type copper-zinc-tin-sulfur-selenide thin film by high-temperature selenization annealing includes: the selenization annealing temperature is 540-560 degrees Celsius, and the annealing time is 12-15 minutes.

[0008] Preferably, the buffer layer has a thickness of 20-50 nanometers.

[0009] Preferably, the window layer and the transparent conductive layer are deposited on the surface of the buffer layer at low temperature, wherein the alkali metal elements are driven to diffuse to the heterojunction interface by low temperature annealing treatment, including: the annealing temperature is 80-150 degrees Celsius.

[0010] Preferably, the window layer and the transparent conductive layer are deposited on the surface of the buffer layer at low temperature, wherein the alkali metal elements are driven to diffuse to the heterojunction interface by low temperature annealing treatment, including: the annealing time is 1.5-3 hours.

[0011] Preferably, the window layer and the transparent conductive layer are deposited on the surface of the buffer layer by low temperature deposition, comprising: the window layer is an intrinsic zinc oxide layer; the transparent conductive layer is an aluminum-doped zinc oxide layer.

[0012] Preferably, the intrinsic zinc oxide layer has a thickness of 40-60 nanometers, and the aluminum-doped zinc oxide layer has a thickness of 200-300 nanometers.

[0013] Preferably, the depositing of a lithium-doped copper-zinc-tin-sulfur precursor film on the back electrode comprises: depositing a precursor solution on a substrate, wherein the substrate includes but is not limited to a molybdenum foil substrate and a molybdenum glass substrate.

[0014] A solar cell comprises a product prepared by any of the above methods for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell.

[0015] The present invention provides a method for regulating the distribution of alkali metals at the heterojunction interface of copper-based thin-film solar cells. Compared to existing technologies, the present invention provides a CdTe solar cell and its preparation method. Through a three-stage process involving doping design of the P-type absorber layer, high-temperature selenization coordinated diffusion, and low-temperature interface reconstruction, this method achieves control of the alkali metal content at the CZTSSe / CdS heterojunction interface, overcoming the random nature of spontaneous doping in traditional soda-lime glass substrates. This method provides a promising foundation for the preparation of high-efficiency, flexible copper-zinc-tin-sulfur-selenium thin-film solar cells, enabling a simple and effective improvement in the photoelectric conversion efficiency of flexible solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is the copper-zinc-tin-sulfur-selenium thin film solar cell structure in Example 1.

[0018] FIG2 is an element depth profile of the CZTSSe:Ref and CZTSSe:Li thin films in Example 2.

[0019] Figure 3 is the formation energy of K interstitial and Li interstitial in cadmium sulfide in Example 2.

[0020] Figure 4 Box plot of Cell-Ref and Cell-Li battery parameters in Example 3. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Please also refer to Figures 1 to 4 The present invention provides a method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell. The method comprises the following steps:

[0023] Step S1, depositing a Li (lithium)-doped copper-zinc-tin-sulfur precursor film on the back electrode;

[0024] In this step, the substrate used includes but is not limited to a molybdenum foil substrate and a molybdenum glass substrate. The copper-zinc-tin-sulfur precursor film is made by depositing a Li (lithium)-doped precursor solution on the back electrode.

[0025] The specific implementation process of this step can be:

[0026] Cu(CH3COO)2·H2O (copper acetate), SnCl2·2H2O (stannous chloride dihydrate), ZnCl2 (zinc chloride), CH4N2S (thiourea), LiCl (lithium chloride), and AgCl (silver chloride) are sequentially dissolved in N,N-dimethylformamide to prepare a precursor solution, wherein the metal molar ratios in the precursor solution are Cu / (Zn+Sn)=0.6~0.75, Zn / Sn=1.0~1.5, Cu+Sn+Zn / S=0.9~1, Ag / (Cu+Ag)=0.05~0.15; Li / (Li+Cu)=0.01~0.20, wherein Li / (Li+Cu)=0.05; Ag / (Cu+Ag)=0.05~0.10 are preferred.

[0027] The precursor solution is then deposited on the flexible substrate by conventional processes such as spin coating.

[0028] Step S2: Prepare a Li-doped P-type copper-zinc-tin-sulfur-selenium absorption layer thin film by high-temperature selenization annealing. The temperature of the selenization annealing is 540-560° C., and the time of the selenization annealing is 12-15 minutes. The alkali metal elements include sodium and potassium.

[0029] The specific implementation process of this step can be: the copper-zinc-tin-sulfur precursor film deposited on the flexible substrate is inverted on Mo glass for selenization annealing, and the Mo glass is soda-lime glass coated with a Mo layer; through selenization annealing, the alkali metal in the soda-lime glass is diffused and doped into the copper-zinc-tin-sulfur-selenium film.

[0030] In this step, inverted placement refers to a placement method in which the copper-zinc-tin-sulfur precursor film faces downward (ie, the copper-zinc-tin-sulfur precursor film faces the Mo layer) and the flexible substrate faces upward.

[0031] In this step, the selenization annealing operation includes: placing selenium particles in a graphite box, mounting Mo glass on the graphite box, and placing the copper-zinc-tin-sulfur precursor film obtained in S1 upside down on the Mo glass, and then heating in a nitrogen atmosphere for selenization annealing.

[0032] Step S3: Remove the selenized copper-zinc-tin-sulfur-selenide film (including the flexible substrate) and deposit a buffer layer CdS (cadmium sulfide) film on the copper-zinc-tin-sulfur-selenide film. Specifically, an N-type buffer layer CdS film is deposited on the surface of the P-type copper-zinc-tin-sulfur-selenide absorber layer; the CdS film has a thickness of 20 to 50 nm, preferably 30 to 50 nm.

[0033] Step S4: A window layer and a transparent conductive layer are then deposited at low temperature on the surface of the buffer layer film. During the low-temperature annealing process, alkali metals diffuse into the heterojunction interface, regulating and reconstructing the alkali metal content and distribution at the heterojunction interface. The window layer is an intrinsic zinc oxide layer. The transparent conductive layer is an aluminum-doped zinc oxide layer. The thickness of the intrinsic zinc oxide layer is 40 to 60 nanometers. The thickness of the aluminum-doped zinc oxide layer is 200 to 300 nanometers. The annealing temperature is 80-150°C, preferably 150°C. The annealing time is 1.5-3 hours, preferably 1.5 hours.

[0034] Step S5: Depositing electrodes on the transparent conductive layer to obtain a copper-zinc-tin-sulfur-selenium thin-film solar cell. The electrodes are one or more of nickel / aluminum, silver, and gold. The thickness of the electrodes is 0.5 to 1.5 microns.

[0035] Example 1

[0036] A method for preparing a copper-zinc-tin-sulfur-selenium thin film solar cell comprises the following steps:

[0037] Cu(CH3COO)2·H2O, SnCl2·2H2O, ZnCl2, CH4N2S, AgCl, and LiCl were dissolved in N,N-dimethylformamide (DMF) in sequence to prepare a precursor solution; the metal molar ratios in the precursor solution were Cu / (Zn+Sn)=0.7, Zn / Sn=1.0, Cu+Sn+Zn / S=1.1, Ag / (Cu+Ag)=0.1, and Li / (Li+Cu)=0.05, respectively; the precursor solution was then spin-coated on a Mo glass substrate to obtain a Li-doped copper-zinc-tin-sulfur precursor film with a thickness of 1.0 μm.

[0038] Selenium particles were placed in a graphite box and a selenization annealing process was carried out in a nitrogen atmosphere at a selenization temperature of 560° C. for 15 minutes to obtain a lithium-doped copper-zinc-tin-sulfur-selenium thin film.

[0039] Based on the water bath deposition method, a cadmium sulfide buffer layer is deposited with a thickness of 40 nanometers, followed by an intrinsic zinc oxide layer with a thickness of 30 nanometers, and then an aluminum-doped zinc oxide layer with a thickness of 350 nanometers is deposited at 150°C, and finally a silver electrode with a thickness of 1.0 micrometer is deposited to obtain a copper-zinc-tin-sulfur-selenium thin film solar cell with a structure as shown below. Figure 1 shown.

[0040] Example 2

[0041] A method for preparing a copper-zinc-tin-sulfur-selenium thin film solar cell comprises the following steps:

[0042] Cu(CH3COO)2·H2O, SnCl2·2H2O, ZnCl2, CH4N2S, LiCl, and AgCl were sequentially dissolved in N,N-dimethylformamide (DMF) to prepare a precursor solution. The metal molar ratios in the precursor solution were Cu / (Zn+Sn) = 0.7, Zn / Sn = 1.0, Cu+Sn+Zn / S = 1.1, Ag / (Cu+Ag) = 0.1, and Li / (Li+Cu) = 0.08, respectively. The precursor solution was then spin-coated onto a flexible Mo foil substrate to produce a Li-doped CuZnSnS precursor film with a thickness of 1.1 microns. Selenium particles were placed in a graphite box, and the CuZnSnS precursor film deposited on the flexible substrate was inverted onto bare soda-lime glass and Mo glass, respectively. Selenization annealing was performed in a nitrogen atmosphere at a temperature of 560°C for 12 minutes.

[0043] A method for preparing a copper-zinc-tin-sulfur-selenium thin film solar cell comprises the following steps:

[0044] Cu(CH3COO)2·H2O, SnCl2·2H2O, ZnCl2, CH4N2S, and AgCl were sequentially dissolved in N,N-dimethylformamide (DMF) to prepare a precursor solution. The metal molar ratios in the precursor solution were Cu / (Zn+Sn) = 0.7, Zn / Sn = 1.0, Cu+Sn+Zn / S = 1.1, and Ag / (Cu+Ag) = 0.1, respectively. This precursor solution was then spin-coated onto a flexible Mo foil substrate to produce a Li-doped CuZnSnS precursor film with a thickness of 1.1 microns. Selenium particles were placed in a graphite box, and the CuZnSnS precursor film deposited on the flexible substrate was inverted and placed onto bare soda-lime glass and Mo glass, respectively. Selenization annealing was performed in a nitrogen atmosphere at a temperature of 560°C for 12 minutes.

[0045] On the above two copper-zinc-tin-sulfur-selenide films, a buffer layer CdS with a thickness of 50 nm was deposited, followed by an intrinsic zinc oxide layer with a thickness of 20 nm, and then an aluminum-doped zinc oxide layer with a thickness of 300 nm was deposited at 150°C. The samples were named CZTSSe:Ref and CZTSSe:Li respectively.

[0046] Deep elemental analysis of the two samples CZTSSe:Ref and CZTSSe:Li was performed. As shown in Figure 2, a Li peak can be detected in the bulk material of sample CZTSSe:Li, while the contents of Na and K are significantly lower than those of CZTSSe:Ref. In addition, a K peak can be detected at the heterojunction of sample CZTSSe:Ref, while this peak disappears in sample CZTSSe:Li, and Li diffuses into the heterojunction of sample CZTSSe:Li. This is mainly because the formation energy of Li interstitial in cadmium sulfide is lower than that of K interstitial, as shown in Figure 2. Figure 3 As shown, for the Li-doped sample, Li first occupies the interstitial position in CdS during the heterojunction annealing process, resulting in a decrease in the number of K interstitials, thereby significantly reducing the K content in CdS.

[0047] Example 3

[0048] A method for preparing a copper-zinc-tin-sulfur-selenium thin film solar cell comprises the following steps:

[0049] Cu(CH3COO)2·H2O, SnCl2·2H2O, ZnCl2, CH4N2S, LiCl, and AgCl were sequentially dissolved in N,N-dimethylformamide (DMF) to prepare a precursor solution. The metal molar ratios in the precursor solution were Cu / (Zn+Sn) = 0.7, Zn / Sn = 1.0, Cu+Sn+Zn / S = 1.1, Ag / (Cu+Ag) = 0.1, and Li / (Li+Cu) = 0.05, respectively. The precursor solution was then spin-coated onto a flexible Mo foil substrate to produce a Li-doped CuZnSnS precursor film with a thickness of 1.2 microns. Selenium particles were placed in a graphite box, and the CuZnSnS precursor film deposited on the flexible substrate was inverted and placed onto bare soda-lime glass and Mo glass, respectively. Selenization annealing was performed in a nitrogen atmosphere at a temperature of 560°C for 12 minutes.

[0050] A method for preparing a copper-zinc-tin-sulfur-selenium thin film solar cell comprises the following steps:

[0051] Cu(CH3COO)2·H2O, SnCl2·2H2O, ZnCl2, CH4N2S, and AgCl were sequentially dissolved in N,N-dimethylformamide (DMF) to prepare a precursor solution. The metal molar ratios in the precursor solution were Cu / (Zn+Sn) = 0.7, Zn / Sn = 1.0, Cu+Sn+Zn / S = 1.1, and Ag / (Cu+Ag) = 0.1, respectively. The precursor solution was then spin-coated onto a flexible Mo foil substrate to produce a Li-doped CuZnSnS precursor film with a thickness of 1.2 microns. Selenium particles were placed in a graphite box, and the CuZnSnS precursor film deposited on the flexible substrate was inverted and placed onto bare soda-lime glass and Mo glass, respectively. Selenization annealing was performed in a nitrogen atmosphere at a temperature of 560°C for 12 minutes.

[0052] On the above two copper-zinc-tin-sulfur-selenide films, a buffer layer CdS with a thickness of 50 nanometers was deposited, followed by an intrinsic zinc oxide layer with a thickness of 20 nanometers. Then, an aluminum-doped zinc oxide layer with a thickness of 300 nanometers was deposited at 150°C, and then an Ag electrode was deposited to obtain the corresponding battery devices, named Cell-Ref and Cell-Li respectively.

[0053] in, Figure 3 The figure shows a box plot of the device's cell parameters. Compared to the Cell-Ref, the Cell-Li device exhibits significant performance improvements, including significant improvements in average efficiency, short-circuit current, open-circuit voltage, and fill factor. This indicates that the method provided by this invention, which regulates the alkali metal distribution at the heterojunction interface of copper-based thin-film solar cells, significantly improves device performance and significantly increases the open-circuit voltage.

[0054] Compared with the prior art, the present invention provides a method for regulating the distribution of alkali metals at the heterojunction interface of copper-based thin-film solar cells. By doping the copper-zinc-tin-sulfur-selenium thin film with light alkali metal Li, the distribution of alkali metals at the heterojunction interface of the copper-based thin-film solar cell is regulated, thereby avoiding damage to flexible devices caused by excessive heavy alkali metal doping in CdS, significantly improving the photoelectric conversion efficiency of the copper-zinc-tin-sulfur-selenium device, and thus effectively improving the performance of the CZTSSe solar cell. Specifically, through the three-stage process system of doping design of the P-type absorption layer, high-temperature selenization coordinated diffusion and low-temperature interface reconstruction, the alkali metal content of alkali metal elements at the CZTSSe / CdS heterojunction interface is regulated, breaking through the randomness limitation of spontaneous doping of traditional soda-lime glass substrates. This method provides a good foundation for the preparation of high-efficiency flexible copper-zinc-tin-sulfur-selenium thin-film solar cells, and can achieve a simple and effective improvement in the photoelectric conversion efficiency of flexible solar cells. During the low-temperature annealing process, the alkali metal enters the heterojunction interface by diffusion, and the content and distribution of the alkali metal at the heterojunction interface are regulated and reconstructed. As a result, the carrier transmission and collection efficiency is optimized, the open circuit voltage is increased, and the photoelectric conversion efficiency of thin-film solar cells is significantly improved.

[0055] A solar cell, the preparation process of which includes the product prepared by any of the above-mentioned methods for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell.

[0056] In any achievable embodiment, a battery comprises, from bottom to top, a substrate, a back electrode, an absorber layer, a buffer layer, a transparent conductive layer, and a metal electrode stacked sequentially. The substrate is a glass structure, specifically a soda-lime glass (SLG) substrate. The back electrode is a Mo back electrode. The absorber layer is a Li-doped CZTSSe / CZTS absorber layer. The buffer layer is a CdS layer; the window layer is an intrinsic zinc oxide layer. The transparent conductive layer is an aluminum-doped zinc oxide layer. The metal electrode is an Ag electrode.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for regulating the distribution of alkali metals at the heterojunction interface of copper-based thin-film solar cells, characterized in that: The following steps are involved: A lithium-doped copper-zinc-tin-sulfur precursor film is deposited on the back electrode; a lithium-doped P-type copper-zinc-tin-sulfur-selenide film is prepared by high-temperature selenization annealing, wherein the selenization annealing process causes alkali metal elements in the glass substrate to diffuse into the copper-zinc-tin-sulfur-selenide film and achieve doping; a buffer layer is deposited on the copper-zinc-tin-sulfur-selenide film; a window layer and a transparent conductive layer are deposited on the surface of the buffer layer by low temperature, wherein the low-temperature annealing treatment drives the alkali metal elements to diffuse to the heterojunction interface.

2. The method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to claim 1, wherein: The method of depositing a lithium-doped copper-zinc-tin-sulfur precursor film on the back electrode includes: dissolving copper acetate, stannous chloride dihydrate, zinc chloride, thiourea, lithium chloride and silver chloride in N,N-dimethylformamide in sequence to prepare a precursor solution, wherein the molar ratio of the metal elements in the precursor solution satisfies: Cu / (Zn+Sn)=0.6-0.75, Zn / Sn=1.0-1.5, Cu+Sn+Zn / S=1-0.9, Li / (Li+Cu)=0.01-0.20, and Ag / Ag+Cu=0.05-0.

15.

3. A method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to any one of claims 1 or 2, characterized in that: The method of preparing a lithium-doped P-type copper-zinc-tin-sulfur-selenide thin film by high-temperature selenization annealing includes: the selenization annealing temperature is 540-560 degrees Celsius, and the annealing time is 12-15 minutes.

4. The method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to claim 3, wherein: The thickness of the buffer layer is 20-50 nanometers.

5. The method for regulating the distribution of alkali metals at the heterojunction interface of copper-based thin-film solar cells according to claim 3, wherein: The window layer and the transparent conductive layer are deposited on the surface of the buffer layer at low temperature, wherein the alkali metal elements are driven to diffuse to the heterojunction interface by low temperature annealing treatment, including: the annealing temperature is 80-150 degrees Celsius.

6. The method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to claim 5, wherein: The window layer and the transparent conductive layer are deposited on the surface of the buffer layer at low temperature, wherein the alkali metal elements are driven to diffuse to the heterojunction interface by low temperature annealing treatment, including: the annealing time is 1.5-3 hours.

7. The method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to claim 3, wherein: The method comprises depositing a window layer and a transparent conductive layer on the surface of the buffer layer at low temperature, wherein the window layer is an intrinsic zinc oxide layer; and the transparent conductive layer is an aluminum-doped zinc oxide layer.

8. The method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to claim 7, wherein: The thickness of the intrinsic zinc oxide layer is 40-60 nanometers, and the thickness of the aluminum-doped zinc oxide layer is 200-300 nanometers.

9. The method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell according to claim 2, wherein: The method of depositing a lithium-doped copper-zinc-tin-sulfur precursor film on the back electrode includes depositing a precursor solution on a substrate, wherein the substrate includes but is not limited to a molybdenum foil substrate and a molybdenum glass substrate.

10. A solar cell, characterized in that: The invention comprises a product prepared by the method for regulating the distribution of alkali metals at the heterojunction interface of a copper-based thin-film solar cell as described in any one of claims 1 to 9.

Images