CdTe power generation glass window layer CdSe film thickness confirmation method and CdTe power generation glass preparation method

Abstract

The invention belongs to the technical field of photoelectric cells, and discloses a CdTe power generation glass window layer CdSe film thickness confirmation method and a CdTe power generation glass preparation method, and the preparation method comprises the following steps: determining CdTe power generation glass with a CdSe window layer as a to-be-tested unit, and carrying out an IV test on the CdTe power generation glass to obtain a first test result; performing a CdSe film thickness test on the unit to be tested to obtain a second test result; and based on the first test result and the second test result, constructing a correlation mathematical model of the CdSe film thickness and the IV test, and calculating the actual CdSe film thickness. The method provided by the invention has the advantages of high test speed, low equipment cost, simplicity and convenience in operation, high accuracy and the like. By implementing the method, the production efficiency and the performance stability of the CdTe power generation glass can be improved, and application and development of the CdTe power generation glass in the field of renewable energy sources are promoted. And the CdTe power generation glass is researched, developed and prepared based on the determination method, so that the accuracy of determining the thickness of the CdSe film can be improved, and the performance of the CdTe power generation glass can be optimized.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and more specifically, to a method for confirming the CdSe film thickness of the CdTe power generation glass window layer and a method for preparing CdTe power generation glass. Background Technology

[0002] CdTe solar cells hold a significant position in the field of thin-film solar cells due to their high conversion efficiency and low manufacturing cost. The window layer, as a crucial component of CdTe solar cells, has a significant impact on cell performance. For CdSe thin films, which serve as the light-absorbing or electron-transporting layer of the solar cell, their thickness can affect the following aspects:

[0003] Light absorption efficiency: Thinner CdSe films may not absorb sunlight sufficiently, resulting in reduced photoelectric conversion efficiency. Thicker CdSe films may increase light absorption, but excessive thickness may also lead to multiple reflections and light loss within the film, or increase the transport distance of charge carriers within the film, thereby increasing recombination losses.

[0004] Carrier transport: The thickness of the thin film affects the transport distance of charge carriers (electrons and holes) from the light-absorbing layer to the electrode. Thicker films may increase the transport distance, thereby increasing recombination losses and resistive losses.

[0005] Battery performance: Considering both light absorption efficiency and carrier transport, there exists an optimal CdSe film thickness that maximizes the photoelectric conversion efficiency of the solar cell. The film thickness also affects the cell's stability. Thicker films may offer better mechanical stability and weather resistance, but may also increase manufacturing costs and complexity.

[0006] However, traditional methods for determining CdSe film thickness, such as X-ray diffraction (XRD) and scanning electron microscopy (SEM), suffer from drawbacks such as long testing times, high equipment costs, and complex operations, hindering large-scale production and rapid testing. Other methods, such as metallurgical microscopy, can be affected by various factors including sample surface condition and testing environment, limiting the accuracy of measurement results. While electron microscopy offers high resolution, it requires complex equipment and technical support, and places high demands on sample preparation. Furthermore, traditional methods may only be applicable to CdSe films within a specific thickness range, and may fail to accurately measure excessively thin or thick films. The testing ranges of different methods may overlap, but gaps may also exist, preventing the effective measurement of certain CdSe films of specific thicknesses. Measurement accuracy can be affected by various factors such as instrument precision and operational errors, resulting in a certain range of error in the measurement results. Especially when measuring thinner CdSe films, the weaker measurement signal makes them more susceptible to interference and errors, and some specific measurement methods require complex operating procedures and specialized skills. This not only increases the difficulty and time cost of testing, but also may introduce errors due to improper operation, and is costly, as methods such as electron microscopy and X-ray diffraction require expensive equipment and maintenance. This limits the feasibility of these methods in widespread application, especially when a large number of tests are required, as timely response and monitoring are impossible. Therefore, developing a rapid, accurate, and low-cost method for determining CdSe film thickness is of great significance. Summary of the Invention

[0007] In view of this, the present invention provides a method for confirming the CdSe film thickness of the window layer of CdTe power generation glass and a method for preparing CdTe power generation glass, so as to solve the above problems.

[0008] To solve the above technical problems, the present invention provides

[0009] A method for confirming the CdSe film thickness of the CdTe power-generating glass window layer, the method comprising:

[0010] A CdTe photovoltaic glass with a CdSe window layer was selected as the test unit, and IV test was performed on it to obtain the first test result.

[0011] The CdSe film thickness of the test cell is tested to obtain a second test result. Based on the first and second test results, a mathematical model relating the CdSe film thickness to the IV test is constructed, and the actual CdSe film thickness is calculated.

[0012] As an optional approach, the first test results include the current-voltage characteristic curve and key parameters of the unit under test, including open-circuit voltage, short-circuit current, fill factor, and conversion efficiency.

[0013] As an alternative approach, a mathematical model relating CdSe film thickness to IV testing is used to reflect the impact of CdSe film thickness on battery performance. This model includes the following parameters:

[0014] Short-circuit current, quantum efficiency, photon flux, electron charge, effective area and CdSe film thickness;

[0015] The effective area represents the area of ​​the CdSe thin film that is illuminated and generates current.

[0016] As an optional approach, the calculation of CdSe film thickness also includes correction constants for fixed parameters and the influence factors of CdSe material properties and process flow.

[0017] As an alternative approach, when constructing the mathematical model relating CdSe film thickness to IV testing, the model is determined based on the relationship between CdSe film thickness and the key parameter short-circuit current.

[0018] As an alternative, the CdSe film thickness of the unit under test can be measured using the RXF method and / or a film thickness measuring instrument.

[0019] On the other hand, the present invention also provides a method for preparing CdTe power-generating glass, which uses the CdSe film thickness confirmation method for the CdTe power-generating glass window layer as described above to confirm the film thickness, and includes the following preparation steps:

[0020] Prepare a glass substrate, place a TCO front electrode on the other side of the glass substrate that receives sunlight, and perform a large-area near-space evaporation method on the TCO front electrode to deposit a CdSe window layer.

[0021] A CdTe absorption layer was deposited on a CdSe window layer by a large-area near-space evaporation method.

[0022] The CdTe absorber layer is etched to form a textured surface;

[0023] The CdTe absorber layer was magnetron sputtered to deposit the back contact layer.

[0024] The back contact layer is magnetron sputtered to deposit a metal back electrode.

[0025] As an alternative approach, when configuring CdTe power-generating glass, the treated glass substrate, TCO front electrode, CdSe window layer, and CdTe absorber layer are arranged sequentially; the metal back electrode is located between the CdTe absorber layer and the back contact layer.

[0026] As an alternative, laser etching is used to segment CdTe power-generating glass sub-cells.

[0027] As an alternative, CdTe photovoltaic glass is cadmium telluride photovoltaic glass.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention provides a method for rapidly determining the CdSe film thickness of the window layer in CdTe photovoltaic glass using IV testing. This method offers advantages such as fast testing speed, low equipment cost, simple operation, and high accuracy. Implementing this method will help improve the production efficiency and performance stability of CdTe photovoltaic glass, promoting its application and development in the renewable energy field. Furthermore, research and development based on this method improves the accuracy of CdSe film thickness determination, which is beneficial for optimizing the performance of CdTe photovoltaic glass. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the CdSe film thickness determination process provided in an embodiment of the present invention;

[0031] Figure 2 An IV test curve for a specific scenario provided in this embodiment of the invention;

[0032] Figure 3 A schematic diagram of a cadmium telluride power-generating glass structure with a back contact layer provided in an embodiment of the present invention;

[0033] Figure 4 This is a quantum efficiency test curve provided in one scenario according to an embodiment of the present invention.

[0034] Figure labels and their correspondences:

[0035] 1-Glass substrate, 2-TCO front electrode, 3-CdSe window layer, 4-CdTe absorber layer, 5-Metal back electrode, 6-Back contact layer. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0037] A solar cell is a device that converts light energy into electrical energy, and its working principle is based on the photoelectric effect. When sunlight shines on a solar cell, photons are absorbed by the semiconductor material inside the cell, exciting electrons. These electrons move inside the semiconductor, forming an electric current, thereby generating electrical energy. CdSe, as an N-type semiconductor material, has wide applications in the field of solar cells due to its moderate bandgap at room temperature and its ability to effectively absorb visible light energy.

[0038] As a crucial component of solar cells, the thickness of the CdSe thin film significantly impacts cell performance. On one hand, the thickness of the CdSe film determines its light absorption capacity, thus affecting the cell's photoelectric conversion efficiency. On the other hand, the thickness of the CdSe film also influences performance parameters such as internal resistance and stability. Therefore, accurately measuring the thickness of the CdSe film is essential for optimizing solar cell performance.

[0039] IV testing is a commonly used electrochemical testing method. By measuring the current response of a battery at different voltages, the current-voltage characteristic curve (i.e., IV curve) of the battery can be obtained. This curve reflects the battery's performance parameters, such as open-circuit voltage, short-circuit current, fill factor, and conversion efficiency. These parameters are closely related to the battery's structure, materials, and manufacturing process. Therefore, IV testing can indirectly reflect the thickness information of the CdSe thin film in a solar cell.

[0040] Due to time and personnel constraints during the manufacturing process of photovoltaic glass, film thickness testing is not performed on every single piece of glass. Conventional production lines perform random checks on film thickness, which cannot comprehensively cover the thickness accuracy of every batch of photovoltaic glass. Therefore, this embodiment considers that each piece of photovoltaic glass needs to undergo IV testing. Thus, the results of the IV test can be used to infer whether there are any glasses with significantly abnormal film thickness. For this purpose, please refer to... Figure 1 and Figure 2 This embodiment, based on the working principle of CdTe solar cells and IV testing technology, quickly determines the CdSe film thickness by measuring the cell's IV characteristic curve and combining it with theoretical model analysis, using the IV test results to infer the film thickness. This embodiment is implemented as follows:

[0041] First, a CdTe photovoltaic glass with a CdSe window layer was selected as the test unit, and an IV test was performed to obtain the first test result. In this embodiment, conventional IV testing equipment was used to test the current-voltage characteristics of the sample, without limiting the testing equipment. In an optional manner, the AM1.5 spectral standard was uniformly adopted during the testing process, with a test temperature of 25±2℃ and a light intensity of 1000W / m². 2 The testing machine is an AAA-level simulator, and the test yields a smooth IV curve and corresponding key parameters, such as... Figure 2 As shown.

[0042] Subsequently, the CdSe film thickness of the cell under test is measured to obtain a second test result. Optionally, the CdSe film thickness of the cell under test can be measured using the RXF method and / or a film thickness measuring instrument. The purpose is to combine the theoretical model of CdTe solar cells, perform CdSe film thickness measurement using XRF before each IV test, and then analyze the relationship between CdSe film thickness and the key parameter Isc after the IV test.

[0043] Based on the results of the first and second tests, a mathematical model relating CdSe film thickness to IV testing is constructed, and the actual CdSe film thickness is calculated.

[0044] In this embodiment, please refer again. Figure 2 The initial test results include key parameters extracted from the IV curves, such as open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF), and conversion efficiency (η). These parameters reflect the battery's performance level and form the basis for subsequent analysis. Figure 2 In this model, Pmpp represents peak power, Impp represents peak current, Umpp represents peak voltage, and Rseries represents series resistance. By fitting the second test result with the first test result, and through theoretical derivation and experimental verification, a mathematical model of the relationship between CdSe film thickness and IV curve parameters can be established. This model should accurately reflect the impact of CdSe film thickness on battery performance, and is shown below:

[0045] Isc=η·φ·q·A·g(tCdSe)

[0046] in:

[0047] Isc: Short-circuit current;

[0048] η: is the quantum efficiency, representing the proportion of absorbed photons that can generate an effective current;

[0049] φ: Photon flux, representing the number of photons per unit area that hits the thin film per unit time (this is usually proportional to the light intensity);

[0050] q: The charge of an electron (a constant, approximately 1.602 × 10⁻⁶). -19 coulomb);

[0051] A: Effective area (i.e., the area of ​​the CdSe thin film that is illuminated and generates current);

[0052] g(tCdSe)=atCdSe2+btCdSe+c, where a, b and c are constants that need to be determined by fitting experimental data. They depend on all other fixed parameters and the properties of CdSe material. They need to be appropriately modified when other processes change.

[0053] tCdSe: CdSe film thickness.

[0054] Thus, based on this associated mathematical model and the IV curve parameters, the CdSe film thickness can be calculated. It is important to note that during the calculation process, the accuracy of the input parameters and the applicability of the model should be ensured. Through calculation, numerical results for the CdSe film thickness can be obtained quickly.

[0055] Through the above-described scheme, this embodiment achieves rapid measurement via IV testing, significantly improving testing efficiency compared to traditional methods for determining CdSe film thickness. Furthermore, the IV testing equipment is relatively simple and inexpensive, reducing testing costs. Combined with theoretical model analysis, the accuracy of CdSe film thickness determination is improved, which is beneficial for optimizing the performance of CdTe photovoltaic glass.

[0056] On the other hand, this embodiment also provides a method for preparing CdTe power-generating glass, using the CdSe film thickness confirmation method for the CdTe power-generating glass window layer as described above to confirm the film thickness. It includes the following preparation steps:

[0057] Prepare a glass substrate, place a TCO front electrode on the other side of the glass substrate that receives sunlight, and perform a large-area near-space evaporation method on the TCO front electrode to deposit a CdSe window layer.

[0058] A CdTe absorption layer was deposited on a CdSe window layer by a large-area near-space evaporation method.

[0059] The CdTe absorber layer is etched to form a textured surface;

[0060] The CdTe absorber layer was magnetron sputtered to deposit the back contact layer.

[0061] The back contact layer is magnetron sputtered to deposit a metal back electrode.

[0062] As an optional method, please refer to Figure 3 In configuring the CdTe power generation glass, the treated glass substrate, TCO front electrode, CdSe window layer, and CdTe absorber layer are arranged sequentially; the metal back electrode is located between the CdTe absorber layer and the back contact layer. The CdTe power generation glass sub-cells are segmented using laser etching. Furthermore, in one embodiment, the CdTe power generation glass can be selected as cadmium telluride power generation glass.

[0063] After the CdTe power generation glass is fabricated, it can be subjected to IV testing as described above. Since CdSe is a direct bandgap N-type semiconductor, it acts as a window layer, combined with the CdTe absorption layer, forming a heterojunction at the interface. The bandgap width of CdSe is 1.7 eV, corresponding to an absorption wavelength of approximately 730 nm. Therefore, CdSe bulk material exhibits strong absorption capabilities in the visible and near-infrared regions. CdSe can improve the energy level matching and carrier transport performance at the junction interface, thereby reducing recombination of photogenerated carriers and improving battery efficiency. The buffer layer CdSe plays a significant role in improving the photoelectric conversion efficiency of the CdTe power generation glass. Film thickness is a key parameter; insufficient CdSe thickness may not effectively block the return flow of electrons to the back electrode, leading to a decrease in carrier collection efficiency. When the CdSe film thickness is too thick, it may increase light absorption and reflection, resulting in a reduction in the number of photons reaching the CdTe absorption layer, which reduces the photogenerated current of the battery. In one embodiment, through the correlation mathematical model and IV test results as described above, such as... Figure 4 As shown, the increase in the atomic percentage of Se represents an increase in film thickness. Therefore, as the CdSe thickness increases, the upper limit of the spectral response wavelength shifts from 820 nm to 900 nm. Thus, in the scenario described in this embodiment, the optimal thickness range for the window layer CdSe is 90–150 nm. Based on this optimal thickness, the optimal film thickness for CdTe is 2000–3500 nm. Therefore, when performing IV testing on the power-generating glass, if the IV test results are found to be outside the preset range, the CdSe film thickness problem can be deduced using the method described in this embodiment. In addition to immediate sampling inspection, the film thickness can also be quickly determined during routine testing.

[0064] This embodiment provides a method for rapidly determining the CdSe film thickness of the window layer in CdTe photovoltaic glass using IV testing. This method offers advantages such as fast testing speed, low equipment cost, simple operation, and high accuracy. Implementing this method will help improve the production efficiency and performance stability of CdTe photovoltaic glass, promoting its application and development in the renewable energy field. Furthermore, this method is non-destructive, rapid, and accurate, which is of great significance for optimizing the performance of solar cells. Therefore, research and development can be conducted based on this method, improving the accuracy of CdSe film thickness determination and facilitating the optimization of CdTe photovoltaic glass performance.

[0065] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for confirming the CdSe film thickness of a CdTe power-generating glass window layer, characterized in that, The method includes: A CdTe photovoltaic glass with a CdSe window layer was selected as the test unit, and IV test was performed on it to obtain the first test result. The CdSe film thickness is tested on the unit under test to obtain a second test result; based on the first test result and the second test result, a mathematical model relating CdSe film thickness to IV test is constructed, and the actual CdSe film thickness is calculated.

2. The method for confirming the CdSe film thickness of the CdTe power generation glass window layer according to claim 1, characterized in that, The first test results include the current-voltage characteristic curve and key parameters of the unit under test, including open-circuit voltage, short-circuit current, fill factor and conversion efficiency.

3. The method for confirming the CdSe film thickness of the CdTe power-generating glass window layer according to claim 2, characterized in that, The mathematical model relating CdSe film thickness to IV testing is used to reflect the impact of CdSe film thickness on battery performance, and it includes the following parameters: Short-circuit current, quantum efficiency, photon flux, electron charge, effective area and CdSe film thickness; The effective area represents the area of ​​the CdSe thin film that is illuminated and generates current.

4. The method for confirming the CdSe film thickness of the CdTe power-generating glass window layer according to claim 3, characterized in that, The calculation of the CdSe film thickness also includes correction constants for fixed parameters and the influence factors of CdSe material properties and process flow.

5. The method for confirming the CdSe film thickness of the CdTe power-generating glass window layer according to claim 3, characterized in that, When constructing the mathematical model relating CdSe film thickness to IV testing, the model is determined based on the relationship between CdSe film thickness and the key parameter short-circuit current.

6. The method for confirming the CdSe film thickness of the CdTe power generation glass window layer according to claim 1, characterized in that, The CdSe film thickness of the unit under test is measured using the RXF method and / or a film thickness measuring instrument.

7. A method for preparing CdTe power-generating glass, wherein the film thickness is confirmed using the method for confirming the CdSe film thickness of the CdTe power-generating glass window layer as described in any one of claims 1-6, characterized in that, It includes the following preparation steps: Prepare a glass substrate, and place a TCO front electrode on the other side of the glass substrate that receives sunlight. Then, perform a large-area near-space evaporation method on the TCO front electrode to deposit a CdSe window layer. A CdTe absorber layer is deposited on the CdSe window layer by a large-area near-space evaporation method. The CdTe absorber layer is etched to form a textured structure; The CdTe absorber layer was magnetron sputtered to deposit a back contact layer; The back contact layer is magnetron sputtered to deposit a metal back electrode.

8. The method for preparing CdTe photovoltaic glass according to claim 7, characterized in that, When configuring the CdTe power generation glass, the treated glass substrate, TCO front electrode, CdSe window layer and CdTe absorption layer are arranged in sequence; the metal back electrode is located between the CdTe absorption layer and the back contact layer.

9. The method for preparing CdTe photovoltaic glass according to claim 7, characterized in that, The CdTe power-generating glass sub-cells are segmented using laser etching.

10. The method for preparing CdTe power-generating glass according to claim 7, wherein, as an optional method, the CdTe power-generating glass is cadmium telluride power-generating glass.

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