Co-doped cadmium telluride thin film solar cell and preparation method thereof

Abstract

The invention discloses a co-doped cadmium telluride thin film solar cell which comprises a substrate, a first electrode layer, a window layer, an absorption layer and a second electrode layer which are arranged in sequence, and the absorption layer comprises a cadmium telluride thin film co-doped with copper and nitrogen family elements. According to the co-doped cadmium telluride thin film solar cell, copper and nitrogen family elements are co-doped in the cadmium telluride thin film to serve as the absorption layer, the obtained co-doped cadmium telluride thin film solar cell can regulate and control the impurity energy level and improve the hole doping concentration through the interaction of co-doping defects, and therefore the open-circuit voltage of the cadmium telluride thin film solar cell is improved, and the service life of the cadmium telluride thin film solar cell is prolonged. And the conversion efficiency of the cadmium telluride thin film solar cell is improved.

Description

Technical Field

[0001] This application relates to the field of solar cells, and in particular, to a co-doped cadmium telluride thin-film solar cell and a preparation method thereof. Background Art

[0002] To address the problems brought about by the extensive use of fossil fuels, people have gradually started to pay attention to the development of green and renewable energy. Solar energy is an important green and renewable energy, and solar cells are an important means of realizing solar energy utilization through photoelectric conversion.

[0003] Cadmium telluride (CdTe) is a photovoltaic material with excellent performance, having an ideal direct bandgap, and at the same time having advantages such as a high absorption coefficient, a simple phase, easy large-scale production, and high raw material utilization rate. The cadmium telluride thin-film solar cell prepared based on the cadmium telluride absorption layer has the advantages of high energy conversion efficiency, high stability, good low-light performance, low temperature coefficient, wide application scenarios, and simple preparation process, and is a thin-film solar cell with great development prospects. A large number of studies have shown that the main performance parameter restricting the further improvement of the conversion efficiency of the cadmium telluride thin-film solar cell is the relatively low open-circuit voltage.

[0004] Therefore, it is extremely urgent to increase the open-circuit voltage of the cadmium telluride thin-film solar cell and thus improve its conversion efficiency. Summary of the Invention

[0005] In view of this, the co-doped cadmium telluride thin-film solar cell provided by this application has a higher P-type carrier concentration, effectively improving the open-circuit voltage and conversion efficiency of the solar cell.

[0006] This application provides a co-doped cadmium telluride thin-film solar cell, including a substrate, a first electrode layer, a window layer, an absorption layer, and a second electrode layer arranged in sequence, wherein the absorption layer includes a cadmium telluride thin film co-doped with copper and a nitrogen group element.

[0007] In some specific implementation manners, the nitrogen group element includes one or more of nitrogen, phosphorus, arsenic, antimony, or bismuth.

[0008] In some specific implementation manners, the first electrode layer is a fluorine-doped tin dioxide film; the window layer is a tin oxide film; the second electrode layer is one or more of a gold film, a silver film, an aluminum film, a molybdenum film, a tellurium film, a nickel film, or a chromium film; the substrate is soda-lime glass.

[0009] In some specific implementation manners, the thickness of the substrate is 1 mm to 4 mm; the thickness of the first electrode layer is 300 nm to 500 nm; the thickness of the second electrode layer is 50 nm to 300 nm.

[0010] In some specific implementation manners, the thickness of the window layer is 10 nm to 50 nm; the thickness of the absorption layer is 1 μm to 6 μm.

[0011] The present application also provides a method for preparing a co-doped cadmium telluride thin film solar cell, including:

[0012] forming a first electrode layer and a window layer on the surface of a substrate in sequence, depositing a cadmium telluride thin film co-doped with copper and a chalcogen element on the window layer, or performing co-doping of copper and a chalcogen element on the deposited cadmium telluride thin film to form an absorption layer, and forming a second electrode layer on the absorption layer to obtain a co-doped cadmium telluride thin film solar cell.

[0013] In some specific implementation manners, the forming of the absorption layer includes performing co-doping of a chalcogen element and copper while preparing the cadmium telluride thin film, or after preparing the cadmium telluride thin film, spin-coating or soaking a solution containing a chalcogen element and copper on the surface of the cadmium telluride thin film and performing a thermal diffusion treatment to form an absorption layer.

[0014] In some specific implementation manners, the concentration of the solution containing a chalcogen element and copper is 0.0001 mmol / L to 10 mol / L; the rotation speed of the spin-coating is 100 rpm to 7000 rpm, and the dosage of the solution containing a chalcogen element and copper is 10 μL / cm 2 to 200 μL / cm 2 .

[0015] In some specific implementation manners, the soaking time is 1 min to 100 min.

[0016] In some specific implementation manners, the temperature of the thermal diffusion treatment is 100 °C to 600 °C; the time of the thermal diffusion treatment is 1 min to 200 min.

[0017] The present application co-dopes copper and a chalcogen element in the cadmium telluride thin film as the absorption layer. The obtained co-doped cadmium telluride thin film solar cell can utilize the interaction of co-doped defects to regulate impurity energy levels, increase the hole doping concentration, thereby increasing the open-circuit voltage of the cadmium telluride thin film solar cell and improving the conversion efficiency of the cadmium telluride thin film solar cell. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of a co-doped cadmium telluride thin film solar cell provided by an embodiment of the present application;

[0019] Figure 2 is a preparation flow chart of a co-doped cadmium telluride thin film solar cell provided by an embodiment of the present application;

[0020] Figure 3Current-voltage performance graphs of the co-doped cadmium telluride thin-film solar cell provided in Embodiment 1 of this application and the thin-film solar cell provided in Comparative Example 1. Detailed implementation manners

[0021] It should be understood that the expression "one or more of..." separately includes each object recited after said expression and various different combinations of two or more of the recited objects, unless otherwise understood from the context and usage. The expression "and / or" combined with three or more recited objects should be understood to have the same meaning, unless otherwise understood from the context.

[0022] The terms "comprise", "have" or "contain", including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unrecited elements or steps, unless specifically stated otherwise or otherwise understood from the context.

[0023] It should be understood that as long as this application is still operable, the order of steps or the order of performing certain actions is not important. In addition, two or more steps or actions can be carried out simultaneously.

[0024] Currently, how to improve the open-circuit voltage of cadmium telluride thin-film solar cells and thus improve their conversion efficiency is an urgent problem to be solved.

[0025] Theoretically, the technical routes to improve the open-circuit voltage of cadmium telluride thin-film solar cells are as follows: First, optimize the interfacial contact between the functional layers of the cell structure to reduce carrier recombination; second, increase the minority carrier lifetime in CdTe; third, increase the P-type carrier concentration of CdTe. Among them, increasing the P-type carrier concentration of CdTe is one of the important ways to increase the open-circuit voltage.

[0026] In recent years, significant progress has been made in cadmium telluride thin-film solar cells doped with group V elements such as P, As, Sb, and Bi. The group V doping process is divided into in-situ doping and ex-situ doping. In-situ doping means injecting impurities during raw material synthesis or thin-film deposition, and ex-situ doping means doping the doping element into the matrix through methods such as solution spin-coating and ion implantation. This kind of doping often requires heat treatment to assist the diffusion of the doping element. However, due to the relatively large ionic radius of group V elements, the doping efficiency is often low. Therefore, a method of co-doping with group V elements and copper elements is adopted to utilize the interaction between the co-doping elements to increase the solid solubility of group V elements in CdTe. At the same time, through the interaction between the co-doping defects, the impurity energy level is regulated to increase the hole doping concentration, thereby increasing the open-circuit voltage of the cadmium telluride thin-film solar cell and thus increasing the conversion efficiency of the cadmium telluride thin-film solar cell.

[0027] The present application provides a co-doped cadmium telluride thin film solar cell, which includes a substrate, a first electrode layer, a window layer, an absorption layer, and a second electrode layer arranged in sequence. The absorption layer includes a cadmium telluride thin film co-doped with copper and a chalcogen element.

[0028] The structural schematic diagram of the co-doped cadmium telluride thin film solar cell is as Figure 1 shown, where 1 is the substrate. In some specific implementation manners, the substrate includes, but is not limited to, a transparent substrate. The present application has no special requirements for the selection of the substrate. The thickness of the substrate is 1 mm to 4 mm, preferably 3.1 mm to 3.3 mm. 2 is the first electrode layer. In some specific implementation manners, the first electrode layer is a fluorine-doped tin dioxide film, and the thickness of the first electrode layer is 300 nm to 500 nm, preferably 380 nm to 420 nm. Because the first electrode layer has a high transmittance and can avoid the absorption of light by the first electrode layer during incidence, the material of the first electrode layer can be fluorine-doped tin dioxide, abbreviated as FTO, which has excellent light transmittance and conductivity, can allow most of the sunlight to pass through, and effectively transport the electrons in the solar cell to the negative electrode. 3 is the window layer. In some specific implementation manners, the window layer is a tin oxide film, and the thickness of the window layer is 10 nm to 50 nm, preferably 25 nm to 35 nm. Tin oxide has a large band gap, which can reduce the light absorption during the incidence of sunlight and ensure that more photons are absorbed by the absorption layer. 4 is the absorption layer. In some specific implementation manners, the absorption layer includes a cadmium telluride thin film co-doped with copper and a chalcogen element. The chalcogen element includes, but is not limited to, one or more of nitrogen N, phosphorus P, arsenic As, antimony Sb, or bismuth Bi. The present application has no special requirements for the selection of the chalcogen element. The absorption layer is the film layer in the solar cell that absorbs photons and generates electron-hole pairs. Cadmium telluride has the advantages of a high absorption coefficient and a moderate band gap. Therefore, cadmium telluride is used as the material of the absorption layer. The thickness range of the absorption layer can be 1 to 6 μm. The absorption layer can be manufactured by a near-space sublimation process, and the obtained absorption layer has a high crystallization quality. 5 is the second electrode layer. In some specific implementation manners, the second electrode layer is a metal with a high work function. The metal with a high work function includes, but is not limited to, one or more of a gold film, a silver film, an aluminum film, a molybdenum film, a tellurium film, a nickel film, or a chromium film. The present application has no special requirements for the selection of the metal with a high work function. The thickness of the second electrode layer is 50 nm to 300 nm, preferably 100 nm to 200 nm, and the second electrode layer serves as the positive electrode. 6 is the metal electrode layer. The metal electrode layer and the window layer are jointly arranged on the surface of the first electrode layer and can serve as the negative electrode of the solar cell. In some specific implementation manners, the metal electrode layer is a metal with a high work function of a gold film. The metal with a high work function includes, but is not limited to, one or more of a gold film, a silver film, an aluminum film, a molybdenum film, a tellurium film, a nickel film, or a chromium film. The present application has no special requirements for the selection of the metal with a high work function.

[0029] The present application also provides a method for preparing a co-doped cadmium telluride thin film solar cell, including:

[0030] Forming a first electrode layer and a window layer on a substrate in sequence, depositing a copper and chalcogen co-doped cadmium telluride thin film on the window layer, or performing copper and chalcogen co-doping on the deposited cadmium telluride thin film to form an absorption layer, and depositing and preparing a second electrode layer on the absorption layer to obtain a co-doped cadmium telluride thin film solar cell.

[0031] The preparation flow chart of the co-doped cadmium telluride thin film solar cell is as Figure 2 shown.

[0032] After forming the cadmium telluride thin film, co-doping is performed on the cadmium telluride thin film. In some specific implementation manners, the co-doping includes but is not limited to non-in-situ co-doping. Due to this co-doping method, the solubility of chalcogen in CdTe can be improved by utilizing the interaction between co-doped elements, thereby increasing the acceptor doping concentration of CdTe. At the same time, this interaction will inhibit the formation of donor impurities, reduce the self-compensation effect, and improve the p-type conductivity stability of CdTe. In addition, this co-doping method can also regulate the impurity energy level through the interaction between defects, increase the hole doping concentration, thereby increasing the open circuit voltage of the cadmium telluride thin film solar cell, and further increasing the conversion efficiency of the cadmium telluride thin film solar cell.

[0033] The present application first forms a first electrode layer and a window layer on a substrate in sequence, soaks them in deionized water, acetone, deionized water, ethanol, and deionized water in sequence, cleans each for 30 minutes in a water bath ultrasonic instrument, and after taking them out, dries the water on the surface of the transparent substrate with high-purity nitrogen.

[0034] This application then forms a co-doped cadmium telluride thin film of copper and chalcogen elements on the window layer as the absorption layer. In some specific implementation manners, the method for forming the absorption layer includes: thermally evaporating and growing a substrate including a first electrode layer and a window layer to form cadmium selenide; the time for the thermally evaporating growth is 3 min to 20 min. In some specific implementation manners, the sample including the CdSe layer is placed in a close-spaced sublimation method device, and the substrate temperature is set to 500 to 600 °C, preferably 580 °C. A graphite plate supporting a CdTe powder source is placed below it, the temperature of the source is set to 600 °C to 700 °C, preferably 650 °C, the distance between the substrate surface and the CdTe powder source is 3 mm, and then co-doping is performed. The total thickness of the grown absorption layer is 1 to 6 μm, and the thickness of the absorption layer can be adjusted by changing the heating-up time and the growth time. For example, when the heating-up time and the growth time are 500 seconds and 400 seconds respectively, the thickness of the absorption layer is about 3 μm. The sample including the transparent substrate, the first electrode layer, the window layer and the absorption layer is placed in a thermal evaporation instrument, about 60 mg of CdCl2 powder is evaporated on the sample surface, and then the sample is transferred to a tube furnace for heat treatment at 400 °C for 25 minutes to improve the crystallization quality of CdTe. After cooling to room temperature, the residual CdCl2 powder on the surface is rinsed off with deionized water, and then the sample surface is dried with high-purity nitrogen. In some specific implementation manners, the co-doping includes spin-coating or immersing a solution containing chalcogen elements and copper on the surface of the cadmium telluride thin film, and performing a thermal diffusion treatment to form the absorption layer. In some specific implementation manners, the concentration of the solution containing chalcogen elements and copper is 0.0001 mmol / L to 10 mol / L; the rotation speed of the spin-coating is 100 rpm to 7000 rpm, and the dosage of the solution containing chalcogen elements and copper is 10 μL / cm 2 to 200 μL / cm 2 ; the immersion time is 1 min to 100 min. In some specific implementation manners, the temperature of the thermal diffusion treatment is 100 °C to 600 °C; the time of the thermal diffusion treatment is 1 min to 200 min. The thermal diffusion treatment of the elements deposited on the surface of the absorption layer can be carried out in an air atmosphere. In some specific implementation manners, the solution containing chalcogen elements and copper includes, but is not limited to, a chloride solution of chalcogen elements and copper, and this application has no special requirements for the selection of the solution containing chalcogen elements and copper.

[0035] The present application then forms a second electrode layer on the absorption layer. In some specific implementations, the preparation method of the second electrode layer includes evaporating a layer of Au on the above-mentioned absorption layer thin film as the positive electrode of the solar cell, and evaporating a layer of Au on the first electrode layer and the window layer as the negative electrode of the solar cell, to obtain a co-doped cadmium telluride thin film solar cell. The co-doped cadmium telluride thin film solar cell has a higher P-type carrier concentration, effectively improving the open-circuit voltage and conversion efficiency of the solar cell.

[0036] Compared with the single-doped cadmium telluride thin film solar cell, the co-doped cadmium telluride thin film solar cell can utilize the interaction of co-doped defects to regulate the impurity energy level, increase the hole doping concentration, thereby increasing the open-circuit voltage of the cadmium telluride thin film solar cell and improving the conversion efficiency of the cadmium telluride thin film solar cell.

[0037] The following further elaborates on the present application in conjunction with embodiments. The protection scope of the present application is not limited by the following embodiments.

[0038] Embodiment 1

[0039] This embodiment provides a co-doped cadmium telluride thin film solar cell, and the preparation method of the co-doped cadmium telluride thin film solar cell includes:

[0040] S1, cleaning the transparent substrate, the first electrode layer and the window layer. The first electrode layer is 400 nm of FTO, and the window layer is 30 nm of SnO2. The transparent substrate including the first electrode layer and the window layer is successively immersed in deionized water, acetone, deionized water, ethanol and deionized water, and each is cleaned in a water bath ultrasonic instrument for 30 minutes. After taking it out, the water on the surface of the transparent substrate is blown dry with high-purity nitrogen.

[0041] S2, preparation and heat treatment of the absorption layer. The transparent substrate including the first electrode layer and the window layer is placed in a thermal evaporation instrument to grow a 120 nm CdSe thin film. Subsequently, 300 μL of CdCl2 methanol solution (rotation speed: 2000 rpm) is spin-coated on the sample surface, and then the sample is quickly transferred to a tube furnace for heat treatment at 400 °C for 15 minutes.

[0042] Place the above sample containing the CdSe layer in a close-spaced sublimation apparatus, set the substrate temperature to 580 °C, place a graphite plate supporting the CdTe powder source below it, set the source temperature to 650 °C, the distance between the substrate surface and the CdTe powder source is 3 mm, the heating time and growth time are 500 seconds and 400 seconds respectively, the thickness of the absorption layer is about 3 μm. Place the sample containing the transparent substrate, the first electrode layer, the window layer and the absorption layer in a thermal evaporation instrument, evaporate about 60 mg of CdCl2 powder on the sample surface, and then transfer the sample to a tube furnace for heat treatment at 400 °C for 25 minutes to improve the crystallization quality of CdTe. After cooling to room temperature, rinse the residual CdCl2 powder on the surface with deionized water, and then dry the sample surface with high-purity nitrogen gas.

[0043] S3. Codoping of the absorption layer. Spin-coat 150 μL of 1 mmol / L SbCl3 ethanol solution (rotation speed: 5000 rpm) on the above CdTe layer by spin coating, and then place the sample in a rapid thermal processing furnace for heat treatment at 200 °C for 30 minutes. After cooling to room temperature, immerse the sample in 0.1 mmol / L CuCl2 solution for 3 minutes, take it out and dry the excess liquid on the surface with high-purity nitrogen gas, and then put it into a rapid thermal processing furnace for heat treatment at 180 °C for 15 minutes.

[0044] S4. Preparation of the second electrode layer and the metal electrode layer. By thermal evaporation, deposit a layer of Au on the above absorption layer thin film and the first electrode layer respectively as the positive and negative electrodes of the solar cell, and the thickness of Au is about 200 nm.

[0045] Example 2

[0046] This example provides a codoped cadmium telluride thin film solar cell, which is only different from Example 1 in that: in S3, the method of soaking in solution is used for the codoping of antimony element and copper element.

[0047] S3. Codoping of the absorption layer. Place the sample with the absorption layer prepared in S2 in 1 mmol / L SbCl3 solution and soak for 3 minutes, take it out and dry the excess liquid on the surface with high-purity nitrogen gas, and then place the sample in a rapid thermal processing furnace for heat treatment at 200 °C for 30 minutes. After cooling to room temperature, immerse the sample in 0.1 mmol / L CuCl2 solution for 3 minutes, take it out and dry the excess liquid on the surface with high-purity nitrogen gas, and then put it into a rapid thermal processing furnace for heat treatment at 180 °C for 15 minutes.

[0048] The remaining steps S1, S2, and S4 are the same as the operation procedures in Example 1.

[0049] Example 3

[0050] This embodiment provides a co-doped cadmium telluride thin-film solar cell, which is only different from Embodiment 1 in that: in S3, bismuth element and copper element are co-doped.

[0051] S3, co-doping of the absorption layer. Spin-coat 150 μL of 1 mg / L BiCl3 ethanol solution (rotation speed is 5000 rpm) on the above-mentioned CdTe layer by the spin-coating method, and then place the sample in a rapid thermal processing furnace for heat treatment at 300 °C for 30 minutes. After cooling to room temperature, immerse the sample in 0.1 mmol / L CuCl2 solution for 3 minutes, take it out, dry the excess liquid on the surface with high-purity nitrogen, and put it into a rapid thermal processing furnace for heat treatment at 180 °C for 30 minutes.

[0052] The remaining steps S1, S2, and S4 are the same as the operation process in Embodiment 1.

[0053] Embodiment 4

[0054] This embodiment provides a co-doped cadmium telluride thin-film solar cell, which is only different from Embodiment 1 in that: the heat diffusion treatment temperature and time in S3 are different.

[0055] S3, co-doping of the absorption layer. Spin-coat 150 μL of 1 mmol / L SbCl3 ethanol solution (rotation speed is 5000 rpm) on the CdTe layer by the spin-coating method, and then place the sample in a rapid thermal processing furnace for heat treatment at 300 °C for 30 minutes. After cooling to room temperature, immerse the sample in 0.1 mmol / L CuCl2 solution for 3 minutes, take it out, dry the excess liquid on the surface with high-purity nitrogen, and put it into a rapid thermal processing furnace for heat treatment at 180 °C for 30 minutes.

[0056] The remaining steps S1, S2, and S4 are the same as the operation process in Embodiment 1.

[0057] Comparative Example 1

[0058] This comparative example provides a thin-film solar cell, which is only different from Embodiment 1 in that: only single doping of copper is performed in S3.

[0059] S3, single doping of the absorption layer. Immerse the sample with the absorption layer prepared in S2 in 0.1 mmol / L CuCl2 solution for 3 minutes, take it out, dry the excess liquid on the surface with high-purity nitrogen, and put it into a rapid thermal processing furnace for heat treatment at 200 °C for 30 minutes.

[0060] The remaining steps S1, S2, and S4 are the same as the operation process in Embodiment 1.

[0061] Comparative Example 2

[0062] This comparative example provides a thin-film solar cell, which is only different from Example 1 in that: only single doping of antimony is performed in S3. The specific description of S3 is as follows:

[0063] S3, single doping of the absorption layer. Spin-coat 150 μL of 1 mmol / L SbCl3 solution on the CdTe layer by spin coating (rotation speed is 5000 rpm), and then place the sample in a rapid thermal annealing furnace for heat treatment at 200 °C for 30 minutes.

[0064] The remaining steps S1, S2, and S4 are the same as the operation process in Example 1.

[0065] Comparative Example 3

[0066] This comparative example provides a thin-film solar cell, which is only different from Example 1 in that: only single doping of copper is performed in S3, and the doping concentration is 1 mmol / L.

[0067] S3, single doping of the absorption layer. Immerse the sample with the absorption layer prepared in S2 in 1 mmol / L CuCl2 solution for 3 minutes, take it out, dry the excess liquid on the surface with high-purity nitrogen, and put it into a rapid thermal annealing furnace for heat treatment at 180 °C for 30 minutes.

[0068] The remaining steps S1, S2, and S4 are the same as the operation process in Example 1.

[0069] Comparative Example 4

[0070] This comparative example provides a thin-film solar cell, which is only different from Example 1 in that: only single doping of bismuth is performed in S3, and the doping concentration is 10 mg / L.

[0071] S3, single doping of the absorption layer. Spin-coat 150 μL of 10 mg / L BiCl3 solution on the CdTe layer by spin coating (rotation speed is 5000 rpm), and then place the sample in a rapid thermal annealing furnace for heat treatment at 300 °C for 30 minutes.

[0072] The remaining steps S1, S2, and S4 are the same as the operation process in Example 1.

[0073] The co-doped cadmium telluride thin-film solar cells provided in Examples 1-4 and the thin-film solar cells provided in Comparative Examples 1-4 are tested. The test method is as follows: at room temperature, using a solar simulator under one sun (AM 1.5G).

[0074] The test results are shown in Table 1. The current-voltage performance diagrams of the co-doped cadmium telluride thin-film solar cell provided in Example 1 and the thin-film solar cell provided in Comparative Example 1 are as Figure 3as shown

[0075] Table 1

[0076] Open circuit voltage (V) Conversion efficiency (%) Example 1 0.822 18.8 Example 2 0.805 17.5 Example 3 0.837 18.6 Example 4 0.844 18.4 Comparative example 1 0.776 15.9 Comparative example 2 0.775 14.5 Comparative example 3 0.786 14.3 Comparative example 4 0.770 15.1

[0077] As can be seen from the data in Table 1, the open-circuit voltage of Examples 1-4 can reach up to 0.844V, and the conversion efficiency is 17.5% to 18.8%. The open-circuit voltages of the comparative examples are all lower than 0.8V, and the conversion efficiency is 14.3% to 15.9%.

[0078] As described above, the above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application, according to the technical solution of the present application and its application concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present application.

Claims

1. A co-doped cadmium telluride thin film solar cell, characterized in that, It includes a substrate, a first electrode layer, a window layer, an absorption layer, and a second electrode layer which are sequentially arranged, and the absorption layer includes a cadmium telluride thin film co-doped with copper and a chalcogen element.

2. The co-doped cadmium telluride thin film solar cell according to claim 1, characterized in that, The chalcogen element includes one or more of nitrogen, phosphorus, arsenic, antimony, or bismuth.

3. The co-doped cadmium telluride thin film solar cell according to claim 1, characterized in that, The first electrode layer is a fluorine-doped tin dioxide film; the window layer is a tin oxide film; the second electrode layer is one or more of a gold film, a silver film, an aluminum film, a molybdenum film, a tellurium film, a nickel film, or a chromium film; the substrate is soda-lime glass.

4. The co-doped cadmium telluride thin film solar cell according to claim 1, wherein The thickness of the substrate is 1 mm to 4 mm; the thickness of the first electrode layer is 300 nm to 500 nm; the thickness of the second electrode layer is 50 nm to 300 nm.

5. The co-doped cadmium telluride thin film solar cell according to claim 1, characterized in that, The thickness of the window layer is 10 nm to 50 nm; the thickness of the absorption layer is 1 μm to 6 μm.

6. A preparation method of a co-doped cadmium telluride thin film solar cell, characterized in that, It includes: Forming a first electrode layer and a window layer on the surface of the substrate in sequence, depositing a cadmium telluride thin film co-doped with copper and a chalcogen element on the window layer, or performing co-doping of copper and a chalcogen element after depositing the cadmium telluride thin film to form an absorption layer, and forming a second electrode layer on the absorption layer to obtain a co-doped cadmium telluride thin film solar cell.

7. The preparation method according to claim 6, characterized in that, The forming of the absorption layer includes performing co-doping of a chalcogen element and copper while preparing the cadmium telluride thin film, or after preparing the cadmium telluride thin film, spin-coating or soaking a solution containing a chalcogen element and copper on the surface of the cadmium telluride thin film and performing a thermal diffusion treatment to form an absorption layer.

8. The preparation method according to claim 7, characterized in that, The concentration of the solution containing nitrogen group elements and copper is from 0.0001 mmol / L to 10 mol / L; the rotation speed of spin coating is from 100 rpm to 7000 rpm, and the dosage of the solution containing nitrogen group elements and copper is from 10 μL / cm 2 to 200 μL / cm 2 .

9. The preparation method according to claim 7, wherein The soaking time is 1 min to 100 min.

10. The preparation method according to claim 7, characterized in that, The temperature of the thermal diffusion treatment is 100 °C to 600 °C; the time of the thermal diffusion treatment is 1 min to 200 min.

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