Photovoltaic cell and method of manufacturing the same, stacked cell, photovoltaic module

Abstract

The embodiment of the present disclosure relates to the field of photovoltaics, and provides a photovoltaic cell, a preparation method thereof, a laminated cell, and a photovoltaic module. The photovoltaic cell comprises a substrate, a first protective layer located on a surface of the substrate, an aluminum oxide layer located on a surface of the first protective layer away from the substrate, and a second protective layer located on a surface of the aluminum oxide layer away from the first protective layer. The embodiment of the present disclosure is at least beneficial to improving the blistering problem of the aluminum oxide layer, so as to improve the film quality of the aluminum oxide layer.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a photovoltaic cell and its preparation method, a tandem cell, and a photovoltaic module. Background Technology

[0002] In photovoltaic cells, alumina thin films are a crucial thin film layer. Due to the large number of fixed negative charges and low interface state density at the interface, alumina thin films play a pivotal role in photovoltaic cell passivation technology. Currently, various methods can be used to prepare alumina thin films, including thermal oxidation, physical vapor deposition, and chemical vapor deposition.

[0003] However, traditional preparation methods have some problems, such as uneven film thickness, high surface roughness, and susceptibility to blistering in alumina films. These problems ultimately affect the photoelectric conversion efficiency of photovoltaic cells. Furthermore, the contact performance between the prepared alumina film and other layers in the photovoltaic cell requires further investigation. Summary of the Invention

[0004] This disclosure provides a photovoltaic cell and its preparation method, a tandem cell, and a photovoltaic module, which at least helps to improve the blistering problem of the alumina layer, thereby improving the film quality of the alumina layer.

[0005] According to some embodiments of this disclosure, one aspect of this disclosure provides a photovoltaic cell, comprising: a substrate; a first protective layer located on the surface of the substrate; an alumina layer located on the surface of the first protective layer away from the substrate; and a second protective layer located on the surface of the alumina layer away from the first protective layer; wherein both the first protective layer and the second protective layer contain aluminum, and the aluminum content in both the first protective layer and the second protective layer is greater than 90%, while the aluminum content in the alumina layer is less than 90%.

[0006] In some embodiments, the first protective layer and the second protective layer further include hydrogen and carbon elements.

[0007] In some embodiments, the alumina layer comprises N stacked alumina films, where N is a positive integer greater than 1; wherein the aluminum content in the Nth alumina film is higher than the aluminum content in the (N+1)th alumina film; and / or, the hydrogen content in the Nth alumina film is lower than the hydrogen content in the (N+1)th alumina film; and / or, along a first direction, the thickness of the Nth alumina film is less than the thickness of the (N+1)th alumina film; the first direction is the thickness direction of the substrate.

[0008] In some embodiments, the thickness of the first protective layer is 0.3 nm to 1 nm along the first direction; and / or, the thickness of the second protective layer is 0.3 nm to 1 nm along the first direction; the first direction is the thickness direction of the substrate.

[0009] According to some embodiments of this disclosure, another aspect of this disclosure also provides a method for preparing a photovoltaic cell, comprising: providing a substrate and placing the substrate in a reaction chamber; introducing an aluminum source into the reaction chamber to perform a first pretreatment on the substrate to form a first protective layer on the surface of the substrate; forming an aluminum oxide layer on the surface of the first protective layer away from the substrate; and introducing an aluminum source again into the reaction chamber to perform a second pretreatment on the aluminum oxide layer to form a second protective layer on the surface of the aluminum oxide layer away from the substrate.

[0010] In some embodiments, the first pretreatment includes multiple first inlet stages, each of which includes a first inlet step and a first purge step connected in sequence; the first inlet step includes introducing an aluminum source into the reaction chamber, and the first purge step includes introducing a purge gas into the reaction chamber; the second pretreatment includes multiple second inlet stages, each of which includes a second inlet step and a second purge step connected in sequence; the second inlet step includes introducing an aluminum source into the reaction chamber, and the second purge step includes introducing a purge gas into the reaction chamber.

[0011] In some embodiments, the duration of aluminum source introduction in the first introduction step is the same as the duration of aluminum source introduction in the second introduction step; and / or, the gas flow rate of aluminum source in the first introduction step is the same as the gas flow rate of aluminum source in the second introduction step; and / or, the number of cycles in the first introduction stage is the same as the number of cycles in the second introduction stage; and / or, the purging duration of the first purging step is the same as the purging duration of the second purging step.

[0012] In some embodiments, the step of forming the alumina layer includes: forming the alumina layer on the surface of the first protective layer away from the substrate by performing N deposition processes, each of the deposition processes including multiple deposition stages, where N is an integer greater than 1 and less than 6; wherein each of the deposition stages includes a third induction step, a third purging step, a fourth induction step, and a fourth purging step connected sequentially; one of the third induction step and the fourth induction step includes introducing an oxygen source into the reaction chamber, and the other of the third induction step and the fourth induction step includes introducing an aluminum source into the reaction chamber; the third purging step and the fourth purging step include introducing a purging gas into the reaction chamber.

[0013] In some embodiments, the number of cycles of the deposition stage in the Nth deposition process is less than the number of cycles of the deposition stage in the (N+1)th deposition process.

[0014] In some embodiments, the introduction duration of the precursor gas in any deposition stage of the Nth deposition process is a first duration, and the introduction duration of the precursor gas in any deposition stage of the (N+1)th deposition process is a second duration; the gas flow rate of the precursor gas in any deposition stage of the Nth deposition process is a first flow rate, and the gas flow rate of the precursor gas in any deposition stage of the (N+1)th deposition process is a second flow rate; wherein the precursor gas is an oxygen source or an aluminum source, and the first duration is controlled to be greater than the second duration and the first flow rate is less than the second flow rate, or the first duration is controlled to be less than the second duration and the first flow rate is greater than the second flow rate.

[0015] In some embodiments, the third introduction step includes introducing an oxygen source into the reaction chamber, and the fourth introduction step includes introducing an aluminum source into the reaction chamber; wherein, the oxygen source introduction duration in any deposition stage of the Nth deposition process is controlled to be greater than the oxygen source introduction duration in any deposition stage of the (N+1)th deposition process, and the oxygen source gas flow rate in any deposition stage of the Nth deposition process is less than the oxygen source gas flow rate in any deposition stage of the (N+1)th deposition process; the aluminum source introduction duration in any deposition stage of the Nth deposition process is controlled to be less than the aluminum source introduction duration in any deposition stage of the (N+1)th deposition process, and the aluminum source gas flow rate in any deposition stage of the Nth deposition process is greater than the aluminum source gas flow rate in any deposition stage of the (N+1)th deposition process.

[0016] In some embodiments, in the Nth deposition process, the duration of the third infeed step is equal to the duration of the fourth infeed step.

[0017] In some embodiments, the purging time of any fourth purging step in the Nth deposition process is controlled to be less than the purging time of any fourth purging step in the (N+1)th deposition process.

[0018] According to some embodiments of this disclosure, another aspect of this disclosure also provides a tandem battery, comprising: a bottom battery, which is a photovoltaic cell as described in any of the preceding claims, or a photovoltaic cell formed by a method for preparing a photovoltaic cell as described in any of the preceding claims; and a top battery, which is located on one side of the bottom battery.

[0019] According to some embodiments of this disclosure, in another aspect, this disclosure also provides a photovoltaic module, including: a battery string, which is formed by connecting a plurality of photovoltaic cells as described in any one of the above claims, or by connecting a plurality of photovoltaic cells formed by a method for preparing a plurality of photovoltaic cells as described in any one of the above claims, or by connecting a plurality of stacked cells as described above; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film away from the battery string.

[0020] The technical solutions provided in this disclosure have at least the following advantages:

[0021] On the one hand, a first protective layer is designed between the substrate and the alumina layer. This first protective layer is rich in aluminum, and its aluminum content is greater than that of the alumina layer. This alleviates the lattice mismatch problem between the substrate and the alumina layer, reducing the interface state density between the various film layers when the alumina layer is applied, thereby reducing the number of carrier recombination centers. On the other hand, a second protective layer is designed on the surface of the alumina layer away from the first protective layer. This second protective layer is rich in aluminum, and its aluminum content is greater than that of the alumina layer. This prevents the alumina layer from being contaminated or otherwise damaged, maintaining the stability of the negative charge density and passivation effect of the alumina layer. It also allows for better metal fusion between the subsequent electrode and the second protective layer, and prevents the electrode from eroding the alumina layer. On the one hand, it is beneficial to use the first and second protective layers to seal the alumina layer, trapping the residual hydrogen atoms in the alumina layer. This can both saturate the defects in the alumina layer with hydrogen atoms to improve the film quality of the alumina layer and prevent hydrogen atoms from rapidly diffusing to the surface of the substrate to form hydrogen gas, thereby avoiding the problem of blistering or bursting of the alumina layer caused by hydrogen gas, thus improving the film quality of the alumina layer. It can also reduce the risk of hot spots in photovoltaic cells and prevent hydrogen atoms from rapidly diffusing to the interface between the alumina layer and the second protective layer to form hydrogen gas, thereby avoiding the problem of blistering or bursting of the second protective layer caused by hydrogen gas, thus improving the film quality of the second protective layer. It also facilitates the subsequent formation of other high-quality films on the side of the second protective layer away from the alumina layer. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a partial cross-sectional schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure;

[0024] Figure 2 This is another partial cross-sectional schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure;

[0025] Figure 3 A process flow diagram of a method for preparing a photovoltaic cell according to another embodiment of this disclosure;

[0026] Figure 4 This is a partial cross-sectional schematic diagram of a substrate provided in a method for fabricating a photovoltaic cell according to another embodiment of the present disclosure;

[0027] Figure 5 This is a partial cross-sectional schematic diagram of the photovoltaic cell fabrication method provided in another embodiment of the present disclosure after the formation of the first protective layer;

[0028] Figure 6 This is a partial cross-sectional schematic diagram of the photovoltaic cell fabrication method provided in another embodiment of the present disclosure after the formation of the first layer of alumina film;

[0029] Figure 7 This is a partial cross-sectional schematic diagram of the photovoltaic cell fabrication method provided in another embodiment of the present disclosure after the formation of the second layer of alumina film;

[0030] Figure 8 A partial cross-sectional schematic diagram of a stacked battery provided in yet another embodiment of this disclosure;

[0031] Figure 9 A partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in another embodiment of the present disclosure;

[0032] Figure 10 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of the present disclosure.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100, Substrate; 110, First surface side; 120, Second surface side; 101, First protective layer; 102, Alumina layer; 112, Alumina film; 103, Second protective layer; 104, Bottom cell; 105, Top cell; 40, Photovoltaic cell; 41, Encapsulating film; 42, Cover plate; 43, Conductive strip. Detailed Implementation

[0035] As can be seen from the background technology, the film quality of the alumina layer needs to be further improved.

[0036] This disclosure provides a photovoltaic cell and its fabrication method, a tandem cell, and a photovoltaic module. In the photovoltaic cell, on one hand, a first protective layer is designed between the substrate and the alumina layer. The first protective layer is rich in aluminum, and its aluminum content is greater than that of the alumina layer. This alleviates the lattice mismatch problem between the substrate and the alumina layer, reducing the interface state density between the various film layers when the alumina layer is placed, thereby reducing the number of carrier recombination centers. On the other hand, a second protective layer is rich in aluminum, and its aluminum content is greater than that of the alumina layer. This second protective layer is designed on the surface of the alumina layer away from the first protective layer. This not only prevents the alumina layer from being contaminated or otherwise damaged, maintaining the stability of the negative charge density and passivation effect of the alumina layer, but also allows for better metal fusion between the subsequent electrode and the second protective layer. This design improves performance and prevents the electrodes from eroding the alumina layer. Furthermore, it facilitates the sealing of the alumina layer using both the first and second protective layers, trapping residual hydrogen atoms within the alumina layer. This allows for the saturation of defects within the alumina layer with hydrogen atoms, improving film quality, and prevents the rapid diffusion of hydrogen atoms to the substrate surface, thus avoiding blistering or bursting of the alumina layer caused by hydrogen. This also reduces the risk of hot spots in photovoltaic cells and prevents the rapid diffusion of hydrogen atoms to the interface between the alumina layer and the second protective layer, further improving the quality of the second protective layer. Additionally, it facilitates the subsequent formation of other high-quality films on the side of the second protective layer away from the alumina layer.

[0037] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0038] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0039] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0040] In the description of embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0041] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0042] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0043] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0044] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0045] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0046] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0047] This disclosure provides a photovoltaic cell according to one embodiment. The photovoltaic cell provided by this disclosure will be described in detail below with reference to the accompanying drawings.

[0048] refer to Figure 1 or Figure 2 The photovoltaic cell includes: a substrate 100; a first protective layer 101 located on the surface of the substrate 100; an alumina layer 102 located on the surface of the first protective layer 101 away from the substrate 100; and a second protective layer 103 located on the surface of the alumina layer 102 away from the first protective layer 101. Both the first protective layer 101 and the second protective layer 103 contain aluminum, and the aluminum content in both the first protective layer 101 and the second protective layer 103 is greater than 90%, while the aluminum content in the alumina layer 102 is less than 90%.

[0049] in, Figure 1 This is a partial cross-sectional schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure; Figure 2 This is another partial cross-sectional schematic diagram of a photovoltaic cell provided in an embodiment of the present disclosure.

[0050] The alumina layer 102 contains a large number of fixed negative charges, making it an excellent passivation layer. When applied to the substrate 100, it effectively passivates the surface of the substrate 100. For example, it can utilize the large number of fixed negative charges within itself to create an electric field, reducing the recombination rate of charge carriers; it can also saturate the dangling bonds on the surface of the substrate 100, reducing the risk of recombination between electrons and holes on the substrate 100.

[0051] Based on this, on the one hand, a first protective layer 101 is designed between the substrate 100 and the alumina layer 102. The first protective layer 101 is rich in aluminum and the aluminum content in the first protective layer 101 is greater than the aluminum content in the alumina layer 102. Thus, the first protective layer 101 can be used as a transition layer to alleviate the lattice mismatch problem between the substrate 100 and the alumina layer 102, thereby reducing the interface state density between each film layer when the alumina layer 102 is set, and thus reducing the recombination centers of charge carriers.

[0052] On the other hand, a second protective layer 103 is designed on the surface of the alumina layer 102 away from the first protective layer 101. The second protective layer 103 is rich in aluminum and the aluminum content in the second protective layer 103 is greater than the aluminum content in the alumina layer 102. Firstly, the second protective layer 103 can be used as a protective layer to prevent the alumina layer 102 from being contaminated or otherwise damaged by the outside world, so as to maintain the stability of the negative charge density and passivation effect of the alumina layer 102. Secondly, the second protective layer 103 can be used as a metal layer that subsequently contacts the electrode, so that the electrode and the second protective layer 103 have better metal fusion performance and avoid the electrode from corroding the alumina layer 102.

[0053] On the other hand, along the first direction X, i.e., the thickness direction of the substrate 100, protective layers are designed on both sides of the alumina layer 102. This facilitates the sealing of the alumina layer 102 by means of the first protective layer 101 and the second protective layer 103, thus sealing the hydrogen atoms remaining in the alumina layer 102 during the preparation process within the alumina layer 102. Firstly, the defects within the alumina layer 102 can be saturated with hydrogen atoms to improve the film quality of the alumina layer 102, thereby enhancing the passivation effect of the alumina layer 102 on the substrate 100. Secondly, it can prevent hydrogen atoms from rapidly diffusing to the substrate 100. The first protective layer 101 forms hydrogen gas on the surface of the alumina layer 102, thus avoiding blistering or bursting of the alumina layer 102 caused by hydrogen gas, thereby improving the film quality of the alumina layer 102 and reducing the risk of hot spots in the photovoltaic cell. Secondly, it prevents hydrogen atoms from rapidly diffusing to the interface between the alumina layer 102 and the second protective layer 103 to form hydrogen gas, thus avoiding blistering or bursting of the second protective layer 103 caused by hydrogen gas, thereby improving the film quality of the second protective layer 103 and facilitating the subsequent formation of other high-quality films on the side of the second protective layer 103 away from the alumina layer 102. Furthermore, the encapsulation of the alumina layer 102 by the first protective layer 101 and the second protective layer 103 helps reduce the risk of adverse structural changes in the alumina layer 102 at high temperatures, thereby improving the structural stability of the alumina layer 102 and ensuring the stability of its passivation effect.

[0054] Thus, with the cooperation of the first protective layer 101 and the second protective layer 103, not only can the bubbling problem of the alumina layer 102 be improved, but the film quality of the alumina layer 102 can also be improved from multiple aspects, thereby improving the passivation effect of the alumina layer 102 and thus improving the photoelectric conversion efficiency of the photovoltaic cell. Moreover, compared with the alumina layer 102, the electrode and the second protective layer 103 have better metal fusion performance, which can also ultimately improve the photoelectric conversion efficiency of the photovoltaic cell.

[0055] In one example, the material constituting the electrode includes silver, and the second protective layer 103 can achieve silver-aluminum contact between the electrode and the second protective layer 103 to improve the electrode's collection efficiency of charge carriers, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0056] It should be noted that, in some cases, the photovoltaic cell provided in one embodiment of this disclosure, based on the stacked design of the first protective layer 101, the alumina layer 102 and the second protective layer 103, can improve the photoelectric conversion efficiency of the photovoltaic cell by about 0.019% compared to the previous one.

[0057] Furthermore, the aluminum content in the first protective layer 101, the alumina layer 102, and the second protective layer 103 can be determined by the following test methods:

[0058] In some cases, the first protective layer 101, the alumina layer 102, or the second protective layer 103 can be prepared separately, and then the elemental content, such as the aluminum content, in the first protective layer 101, the alumina layer 102, or the second protective layer 103 can be tested using an electron scanner SEM or a mass spectrometer.

[0059] In other cases, samples can be taken from the prepared first protective layer 101, alumina layer 102, or second protective layer 103, and the aluminum content in the first protective layer 101, alumina layer 102, or second protective layer 103 can be measured using EDTA titration, inductively coupled plasma optical emission spectrometry (ICP-OES), wavelength dispersive X-ray fluorescence spectrometry (WDXRF), or inductively coupled plasma optical emission spectrometry (ICP-OES).

[0060] In some other cases, after the formation of the stacked structure of the first protective layer 101, the alumina layer 102, and the second protective layer 103, cross-sectional analysis can be performed, such as using electron probe microanalysis (EPMA) or laser-induced breakdown spectroscopy (LIBS) for in-situ micro-area analysis, to obtain the elemental distribution information of the first protective layer 101, the alumina layer 102, or the second protective layer 103 in the stacked structure, thereby measuring the aluminum content in the first protective layer 101, the alumina layer 102, or the second protective layer 103.

[0061] The photovoltaic cell provided in one embodiment of this disclosure will be described in more detail below with reference to the accompanying drawings.

[0062] In some embodiments, reference Figure 1 or Figure 2 The substrate 100 has a first surface side 110 and a second surface side 120 opposite to each other along the first direction X. The stacked structure consisting of the first protective layer 101, the alumina layer 102 and the second protective layer 103 can be located on the first surface side 110.

[0063] In other embodiments, the stacked structure consisting of the first protective layer, the alumina layer, and the second protective layer may also be located on the second surface side, or the stacked structure consisting of the first protective layer, the alumina layer, and the second protective layer may be located on both the first surface side and the second surface side.

[0064] It should be noted that, Figure 1 and Figure 2 The example shown uses a laminated structure consisting of a first protective layer 101, an alumina layer 102, and a second protective layer 103 located on the first surface side 110. In practical applications, the layout and position of the above-mentioned laminated structure can be flexibly arranged on the surface of the substrate.

[0065] In some embodiments, reference Figure 2The alumina layer 102 comprises N stacked alumina films 112, where N is an integer greater than 1 and less than 6. It should be noted that... Figure 2 The example only shows that the alumina layer 102 includes two stacked alumina films 112. In actual applications, N can also be 3, 4 or 5, etc. In actual applications, the number of alumina films 112 in the alumina layer 102 can be designed according to specific requirements.

[0066] In some cases, the aluminum content in the Nth alumina film 112 can be higher than that in the (N+1)th alumina film 112. In other words, the aluminum content in the alumina layer 102 can decrease layer by layer along the direction from the substrate 100 to the alumina layer 102. Thus, compared to the (N+1)th alumina film 112, the Nth alumina film 112 is closer to the substrate 100. The increase in aluminum content is beneficial to increasing the density of fixed negative charges in the Nth alumina film 112, thereby facilitating the formation of a built-in electric field with a higher electric field strength, which enhances the passivation effect on the substrate 100 and further reduces the risk of carrier recombination on the surface of the substrate 100. Moreover, the increase in aluminum content is beneficial to improving the structural stability of the Nth alumina film 112, for example, making the Nth alumina film 112 less prone to phase transition or decomposition, so as to maintain the high negative charge density and passivation effect stability of the Nth alumina film 112.

[0067] In other cases, the hydrogen content in the Nth alumina film 112 can be lower than that in the (N+1)th alumina film 112. In other words, the hydrogen content in the alumina layer 102 can increase layer by layer along the direction from the substrate 100 to the alumina layer 102. Thus, the increase in hydrogen content is beneficial to improving the hydrogen passivation effect of the (N+1)th alumina film 112 itself. Moreover, under high temperature conditions, the subsequent alumina layer 102 may also promote the diffusion of a small amount of hydrogen from the (N+1)th alumina film 112 to the Nth alumina film 112, thereby improving the hydrogen passivation effect of the Nth alumina film 112 itself.

[0068] In some cases, along the first direction X, the thickness of the Nth alumina film 112 can be less than the thickness of the (N+1)th alumina film 112. The first direction X is the thickness direction of the substrate 100. In other words, along the direction from the substrate 100 to the alumina layer 102, the thickness of the alumina film 112 in the alumina layer 102 can increase layer by layer. Thus, the Nth alumina film 112 can serve as the base layer for preparing the (N+1)th alumina film 112. Designing the Nth alumina film 112 to be thinner helps to reduce the overall internal stress of the Nth alumina film 112, thereby reducing the risk of microcracks or uneven thickness in different areas of the Nth alumina film 112, thereby further improving the film quality of the Nth alumina film 112, and thus providing a better interface foundation for preparing the (N+1)th alumina film 112.

[0069] It should be noted that the alumina layer 102 can be as follows: Figure 1 The image shows a single-layer film structure, which can also be represented as shown below. Figure 2 The diagram shows a multilayer structure. When the alumina layer 102 has a multilayer structure, based on adjustments to the preparation process of the alumina layer 102, the above three scenarios can coexist in the same alumina layer 102, or one or two can be selected to exist in the same alumina layer 102. Furthermore, the improvement effects on the Nth alumina film 112 or the (N+1)th alumina film 112 under each scenario can be additive. In other words, not only can the increased aluminum content in the Nth alumina film 112 result in a higher... The negative charge density and passivation effect make the Nth alumina film 112 less prone to phase transition or decomposition. Furthermore, the increase in hydrogen content in the (N+1)th alumina film 112 can enhance the hydrogen passivation effect of both the (N+1)th and Nth alumina films 112. Additionally, the thinner Nth alumina film 112 can improve the film quality, thereby providing a better interface foundation for the preparation of the (N+1)th alumina film 112.

[0070] Furthermore, the element content or thickness of different layers of alumina film 112 in the alumina layer 102, including the stacked N layers of alumina film 112, can be measured by the following test methods:

[0071] In some cases, after preparing the alumina layer 102 separately, a preliminary observation of the alumina layer 102 can be performed using a scanner for electron microscopy (SEM) or a mass spectrometer to determine the approximate thickness of each alumina film 112 in the alumina layer 102. Alternatively, the content of each element in each alumina film 112 in the alumina layer 102 can be further measured using a scanner for electron microscopy (SEM) or a mass spectrometer.

[0072] In other cases, after forming an alumina layer 102 including N stacked alumina films 112, the elemental distribution information of each alumina film 112 in the alumina layer 102 can be obtained by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), electron probe microanalysis (EPMA), transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS), or secondary ion mass spectrometry (SIMS), thereby measuring the aluminum content or hydrogen content in each alumina film 112 in the alumina layer 102.

[0073] In some other cases, after forming an alumina layer 102 comprising N stacked alumina films 112, the thickness of each alumina film 112 in the alumina layer 102 can be measured using transmission electron microscopy (TEM), focused ion beam scanning electron microscopy (FIB-SEM), spectroscopy (Spectroscopic Ellipsometry), or X-ray reflectance (XRR).

[0074] In some examples, the ratio of aluminum content to oxygen content in the alumina layer 102 can be 2:3, meaning that the material of the alumina layer 102 includes aluminum oxide.

[0075] In some embodiments, reference Figure 1 or Figure 2 Along the first direction X, the thickness of the first protective layer 101 can be 0.3 nm to 1 nm, for example, it can be 0.3 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, or 1 nm, etc., where the first direction X is the thickness direction of the substrate 100. Based on this, such a thin first protective layer 101 has almost no effect on incident light; in other words, incident light can pass through the first protective layer 101 and be absorbed and utilized by the substrate 100.

[0076] In some embodiments, reference Figure 1 or Figure 2 Along the first direction X, the thickness of the second protective layer 103 can be 0.3nm to 1nm, for example, it can be 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, or 1nm, etc., where the first direction X is the thickness direction of the substrate 100. Based on this, such a thin second protective layer 103 has almost no effect on incident light; in other words, incident light can pass through the second protective layer 103 and ultimately be absorbed and utilized by the substrate 100.

[0077] In some embodiments, reference Figure 1 or Figure 2 Both the first protective layer 101 and the second protective layer 103 contain aluminum as the main component. For example, the aluminum content in the first protective layer 101 and / or the second protective layer 103 is greater than 90%.

[0078] In some cases, the first protective layer 101 and the second protective layer 103 may contain small amounts of other elements besides a large amount of aluminum, such as hydrogen or carbon. Furthermore, the first protective layer 101, which is closer to the substrate 100, may also contain the same semiconductor elements as the substrate 100; the first protective layer 101 or the second protective layer 103, which is closer to the alumina layer 102, may also contain the same oxygen elements as the alumina layer 102. Based on this, the first protective layer 101 can be considered as the first aluminum layer, and the second protective layer 103 can be considered as the second aluminum layer.

[0079] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0080] In other embodiments, the substrate 100 may also be made of a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, and copper indium selenide. The following description uses silicon as the material for the substrate 100 as an example.

[0081] In one example, the substrate 100 is a silicon substrate, and the first protective layer 101 closer to the substrate 100 may also contain silicon.

[0082] In summary, on the one hand, designing a first protective layer 101 between the substrate 100 and the alumina layer 102 can alleviate the lattice mismatch problem between the substrate 100 and the alumina layer 102, thereby reducing the interface state density between the various film layers when the alumina layer 102 is set, and thus reducing the recombination centers of charge carriers. On the other hand, designing a second protective layer 103 on the surface of the alumina layer 102 away from the first protective layer 101 can not only prevent the alumina layer 102 from being contaminated or otherwise damaged, thus maintaining the stability of the negative charge density and passivation effect of the alumina layer 102, but also enable better metal fusion performance between the subsequent electrode and the second protective layer 103, and prevent the electrode from eroding the alumina layer 102. Furthermore, it is beneficial to use the first protective layer 101 and the second protective layer 103 to achieve the protection of the alumina layer 102. The sealing process traps residual hydrogen atoms within the alumina layer 102. This not only saturates the defects within the alumina layer 102 with hydrogen atoms, thus improving the film quality of the alumina layer 102, but also prevents hydrogen atoms from rapidly diffusing to the surface of the substrate 100 to form hydrogen gas. This avoids blistering or bursting of the alumina layer 102 caused by hydrogen gas, thereby improving the film quality of the alumina layer 102 and reducing the risk of hot spots in the photovoltaic cell. Furthermore, it prevents hydrogen atoms from rapidly diffusing to the interface between the alumina layer 102 and the second protective layer 103 to form hydrogen gas, thus avoiding blistering or bursting of the second protective layer 103 caused by hydrogen gas. This also improves the film quality of the second protective layer 103 and facilitates the subsequent formation of other high-quality films on the side of the second protective layer 103 away from the alumina layer 102.

[0083] Another embodiment of this disclosure provides a method for preparing a photovoltaic cell, used to prepare the photovoltaic cell provided in the foregoing embodiments. The method for preparing a photovoltaic cell according to another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments will not be repeated here.

[0084] Reference Figures 3 to 7 , Figure 3 This is a process flow diagram of a method for preparing a photovoltaic cell according to another embodiment of the present disclosure. The method for preparing a photovoltaic cell includes at least the following steps:

[0085] S1: Reference Figure 4 , Figure 4 This is a partial cross-sectional schematic diagram of a substrate provided in a method for preparing a photovoltaic cell according to another embodiment of the present disclosure, wherein a substrate 100 is provided and the substrate 100 is placed in a reaction chamber.

[0086] S2: Refer to Figure 4 and Figure 5 , Figure 5This is a partial cross-sectional view of a photovoltaic cell fabrication method provided in another embodiment of the present disclosure after the formation of the first protective layer. An aluminum source is introduced into the reaction chamber to perform a first pretreatment on the substrate 100, so as to form a first protective layer 101 on the surface of the substrate 100.

[0087] S3: Refer to Figures 5 to 7 An aluminum oxide layer 102 is formed on the surface of the first protective layer 101 away from the substrate 100.

[0088] It should be noted that, Figure 6 This is a partial cross-sectional schematic diagram of the photovoltaic cell fabrication method according to another embodiment of the present disclosure after the formation of the first layer of alumina film. Figure 7 This is a partial cross-sectional schematic diagram showing the formation of a second alumina film in a method for fabricating a photovoltaic cell according to another embodiment of this disclosure; furthermore, Figures 5 to 7 This example only illustrates the preparation of a multilayer aluminum oxide layer 102; the method for preparing a multilayer aluminum oxide layer 102 will be described in detail later. In practical applications, a single-layer aluminum oxide layer can also be formed on the surface of the first protective layer away from the substrate.

[0089] S4: Refer to Figure 7 and Figure 2 An aluminum source is introduced into the reaction chamber again to perform a second pretreatment on the alumina layer 102, so as to form a second protective layer 103 on the surface of the alumina layer 102 away from the substrate 100.

[0090] In some cases, on the one hand, due to the structural differences between the areas used for electrode fabrication and those not used in photovoltaic cells, the thickness of the alumina formed in different areas during the alumina fabrication process can vary, thus reducing the quality of the formed alumina film. On the other hand, during the alumina fabrication process, hydrogen may remain in the alumina. In high-temperature environments (e.g., temperatures above 500°C), hydrogen can diffuse rapidly and accumulate on the surface of the substrate, easily forming hydrogen gas. When the hydrogen gas accumulates to a certain amount, the gas pressure caused by the hydrogen gas can exceed the film bonding force of the alumina film, resulting in localized blistering or film bursting of the alumina film, thus reducing the quality of the formed alumina film.

[0091] Based on this, in another embodiment of the photovoltaic cell preparation method provided in this disclosure, before and after the preparation of the alumina layer 102, a first pretreatment and a second pretreatment are designed to be performed sequentially to form a first protective layer 101 and a second protective layer 103 on opposite sides of the alumina layer 102 along the first direction X, which is beneficial to achieve the sealing of the alumina layer 102 by means of the first protective layer 101 and the second protective layer 103. Therefore, it is advantageous to confine the hydrogen atoms remaining in the alumina layer 102 during the preparation process within the alumina layer 102. Firstly, the defects within the alumina layer 102 can be saturated with hydrogen atoms to improve the film quality of the alumina layer 102, thereby enhancing the passivation effect of the alumina layer 102 on the substrate 100. Secondly, it can prevent hydrogen atoms from rapidly diffusing to the surface of the substrate 100 to form hydrogen gas, thus avoiding the problem of blistering or bursting of the alumina layer 102 caused by hydrogen gas, thereby improving the film quality of the alumina layer 102 and reducing the risk of hot spots in photovoltaic cells. Thirdly, it can prevent hydrogen atoms from rapidly diffusing to the interface between the alumina layer 102 and the second protective layer 103 to form hydrogen gas, thereby avoiding the problem of blistering or bursting of the second protective layer 103 caused by hydrogen gas, thereby improving the film quality of the second protective layer 103 and facilitating the subsequent formation of other high-quality films on the side of the second protective layer 103 away from the alumina layer 102. Moreover, the encapsulation of the alumina layer 102 by the first protective layer 101 and the second protective layer 103 helps to reduce the risk of adverse structural changes in the alumina layer 102 at high temperatures, thereby improving the structural stability of the alumina layer 102 and ensuring the stability of its passivation effect.

[0092] Furthermore, before forming the alumina layer 102, a first protective layer 101 is first formed on the surface of the substrate 100, ensuring that the film layer in contact with the surface of the substrate 100 is in an aluminum-rich state. This alleviates the lattice mismatch problem between the substrate 100 and the subsequently formed alumina layer 102, and facilitates the formation of a more stable alumina layer 102 with a higher negative charge density based on the first protective layer 101, thereby improving the passivation capability of the alumina layer 102. In other words, the first protective layer 101 ensures that the subsequent alumina layer 102 can be formed with uniform thickness on the side of the first protective layer 101 away from the substrate 100, thereby reducing the interface state density of the alumina layer 102 and reducing the recombination centers of charge carriers.

[0093] Before forming the alumina layer 102, a second protective layer 103 is formed on the side of the alumina layer 102 away from the first protective layer 101. Firstly, the second protective layer 103 can serve as a protective layer to prevent the alumina layer 102 from being contaminated or otherwise damaged by external factors, so as to maintain the stability of the negative charge density and passivation effect of the alumina layer 102. Secondly, the second protective layer 103 can serve as a metal layer that subsequently contacts the electrode, so that the electrode and the second protective layer 103 have better metal fusion performance, and prevent the electrode from corroding the alumina layer 102.

[0094] In some cases, the uniformity of the thickness of the alumina layer 102 formed by the photovoltaic cell preparation method provided in another embodiment of this disclosure can be improved by about 0.05% compared with the previous method, and the failure rate of the alumina layer 102 can be reduced to below 0.005%.

[0095] In some cases, compared to the current practice of using steam to pretreat the substrate before preparing alumina, in another embodiment of the photovoltaic cell preparation method provided by this disclosure, an aluminum source is introduced into the reaction chamber to perform a first pretreatment on the substrate 100. This helps to reduce the hydrogen content in the formed alumina layer 102 from the source, thereby further reducing the risk of blistering or bursting of the alumina layer 102 due to hydrogen.

[0096] The following will describe in more detail a method for preparing a photovoltaic cell according to an embodiment of the present disclosure, with reference to the accompanying drawings.

[0097] In some embodiments, in conjunction with reference Figure 4 and Figure 5 The first pretreatment may include multiple first introduction stages, and any first introduction stage may include a first introduction step and a first purging step connected in sequence; the first introduction step includes introducing an aluminum source into the reaction chamber, and the first purging step includes introducing a purging gas into the reaction chamber; referring to the reference Figure 7 and Figure 2 The second pretreatment may include multiple second inlet stages, and any second inlet stage may include a second inlet step and a second purging step connected in sequence; the second inlet step includes introducing an aluminum source into the reaction chamber, and the second purging step includes introducing purging gas into the reaction chamber.

[0098] It should be noted that the aluminum source introduced in the first and second introduction steps can be the same or different. In one example, the aluminum source introduced in the first and second introduction steps is the same, for example, trimethylaluminum.

[0099] It should be noted that the purging gases introduced in the first purging step and the second purging step can be the same or different. In one example, the purging gases introduced in the first purging step and the second purging step are the same, for example, both are nitrogen.

[0100] The first pretreatment and the process parameters used in the first pretreatment are described in detail below.

[0101] In some cases, the duration of aluminum source introduction in the first introduction step can be the same as the duration of aluminum source introduction in the second introduction step.

[0102] In one example, the duration of aluminum source introduction in the first introduction step and the duration of aluminum source introduction in the second introduction step can both be 3s to 10s, for example, 3s, 4s, 5s, 6s, 7s, 8s, 9s or 10s, etc.

[0103] In other cases, the gas flow rate of the aluminum source in the first introduction step can be the same as the gas flow rate of the aluminum source in the second introduction step.

[0104] In one example, the gas flow rate of the aluminum source in both the first and second introduction steps can be 12 sccm to 20 sccm, for example, 12 sccm, 13 sccm, 14 sccm, 15 sccm, 16 sccm, 17 sccm, 18 sccm, 19 sccm or 20 sccm, etc.

[0105] In some cases, the number of cycles in the first entry phase can be the same as the number of cycles in the second entry phase.

[0106] In one example, the number of cycles in both the first and second inlet phases can be 1 to 3 times, for example, 1, 2, or 3 times.

[0107] Generally, the number of cycles in the first introduction stage affects the thickness of the first protective layer 101 formed in the first direction X, and the number of cycles in the second introduction stage affects the thickness of the second protective layer 103 formed in the first direction X. Based on this, designing the number of cycles in the first and second introduction stages to be 1 to 3 times helps ensure that both the first and second protective layers 101 and 103 have a small thickness, so as to avoid the first and second protective layers 101 and 103 blocking the incident light.

[0108] In some cases, the purging time of the first purging step can be the same as the purging time of the second purging step.

[0109] In one example, the duration of the first purging step and the duration of the second purging step can both be 10 to 20 seconds, for example, 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, 16 seconds, 17 seconds, 18 seconds, 19 seconds, or 20 seconds.

[0110] It should be noted that during the first pretreatment in step S2 and the second pretreatment in step S4, the above four scenarios can coexist in the same photovoltaic cell fabrication method, which is beneficial for forming a first protective layer 101 and a second protective layer 103 with consistent film structures. In practical applications, one, two, or three of the above four scenarios can also coexist in the same photovoltaic cell fabrication method.

[0111] In some embodiments, reference Figures 5 to 7 , Figure 1 or Figure 2 Along the first direction X, the thickness of the first protective layer 101 can be 0.3nm to 1nm, for example, it can be 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm or 1nm. In this way, it can be ensured that the incident light passes through the first protective layer 101 and is absorbed and utilized by the substrate 100.

[0112] In some embodiments, reference Figure 1 or Figure 2 Along the first direction X, the thickness of the second protective layer 103 can be 0.3nm to 1nm, for example, it can be 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm or 1nm. In this way, it can be ensured that the incident light passes through the second protective layer 103 and is ultimately absorbed and utilized by the substrate 100.

[0113] In some embodiments, in conjunction with reference Figure 6 and Figure 7 The step of forming the alumina layer 102 may include: forming the alumina layer 102 on the surface of the first protective layer 101 away from the substrate 100 by performing N deposition processes. Each deposition process may include multiple deposition stages, where N is an integer greater than 1 and less than 6. Each deposition stage may include a third introduction step, a third purging step, a fourth introduction step, and a fourth purging step that are sequentially connected. One of the third introduction step and the fourth introduction step includes introducing an oxygen source into the reaction chamber, and the other of the third introduction step and the fourth introduction step includes introducing an aluminum source into the reaction chamber. The third purging step and the fourth purging step include introducing a purging gas into the reaction chamber.

[0114] It should be noted that the steps of introducing the oxygen source and the aluminum source in the third and fourth introduction steps can be interchanged. In other words, in a single deposition stage, the oxygen source can be introduced first and then the aluminum source, i.e., the third introduction step includes introducing the oxygen source into the reaction chamber and the fourth introduction step includes introducing the aluminum source into the reaction chamber; or the aluminum source can be introduced first and then the oxygen source, i.e., the third introduction step includes introducing the aluminum source into the reaction chamber and the fourth introduction step includes introducing the oxygen source into the reaction chamber.

[0115] The method for forming the alumina layer 102 will be described in detail below, using the third introduction step, which includes introducing an oxygen source into the reaction chamber, and the fourth introduction step, which includes introducing an aluminum source into the reaction chamber, as examples. It is worth noting that the introduction of an aluminum source into the reaction chamber during the first pretreatment results in a higher aluminum content on the surface of the first protective layer 101 away from the substrate 100. Based on this, the third introduction step, which introduces an oxygen source, is designed to facilitate faster formation of the alumina film 112 on the surface of the first protective layer 101 away from the substrate 100, and can be spaced apart from the introduction of the aluminum source into the reaction chamber during the first pretreatment.

[0116] Furthermore, in the step of forming the alumina layer 102, no other processing steps are interspersed between the N deposition processes, which helps to improve the efficiency of forming the alumina layer 102.

[0117] In some cases, refer to Figure 6 and Figure 7 The process of forming the alumina layer 102 by N deposition processes includes: forming the alumina layer 102 by ALD (Atomic Layer Deposition) process.

[0118] In some cases, refer to Figure 6 and Figure 7 The number of cycles in the deposition stage during the Nth deposition treatment can be less than the number of cycles in the deposition stage during the (N+1)th deposition treatment.

[0119] Generally, the thickness of a single-layer alumina film 112 formed in a single deposition process is affected by the number of cycles in the deposition stage of that single deposition process, which affects the thickness of the single-layer alumina film 112 in the first direction X. Based on this, the number of cycles in the deposition stage of the Nth deposition process can be designed to be less than the number of cycles in the (N+1)th deposition process. Along the direction from the substrate 100 to the alumina layer 102, this allows the thickness of the alumina film 112 in the alumina layer 102 to increase layer by layer. This reduces the overall internal stress of the Nth alumina film 112, thereby reducing the risk of microcracks or uneven thickness in different areas of the Nth alumina film 112, further improving the film quality of the Nth alumina film 112, and thus providing a better interface foundation for the preparation of the (N+1)th alumina film 112.

[0120] Moreover, the more cycles of the deposition stage in a single deposition process, the greater the hydrogen content in the formed alumina film 112 will be, thereby allowing the hydrogen content in the alumina layer 102 to increase layer by layer along the direction from the substrate 100 to the alumina layer 102.

[0121] In one example, N is 2, meaning that the alumina layer 102 is formed by two deposition processes. The number of cycles in the deposition stage of the first deposition process can be 8 to 14 times, for example, 8, 9, 10, 11, 12, 13 or 14 times, etc.; the number of cycles in the deposition stage of the second deposition process can be 17 to 24 times, for example, 17, 18, 19, 20, 21, 22, 23 or 24 times, etc.

[0122] In some cases, refer to Figure 6 and Figure 7 The duration of the precursor gas introduction in any deposition stage of the Nth deposition treatment is the first duration, and the duration of the precursor gas introduction in any deposition stage of the (N+1)th deposition treatment is the second duration; the gas flow rate of the precursor gas in any deposition stage of the Nth deposition treatment is the first flow rate, and the gas flow rate of the precursor gas in any deposition stage of the (N+1)th deposition treatment is the second flow rate. The precursor gas is either an oxygen source or an aluminum source.

[0123] It should be noted that in the Nth deposition process, all process parameters used in different deposition stages can be the same. For example, the introduction time of the precursor gas in the third introduction step of different deposition stages can be the same, and the gas flow rate of the precursor gas in the third introduction step of different deposition stages can also be the same. In the (N+1)th deposition process, all process parameters used in different deposition stages can also be the same. In other words, a single deposition process can be considered as a deposition stage consisting of multiple cycles, and a single deposition stage in a single deposition process can be considered as a cycle, with different cycles being identical.

[0124] In some examples, in conjunction with references Figure 6 and Figure 7 The first deposition time is controlled to be greater than the second deposition time, and the first flow rate is less than the second flow rate. In other words, regardless of whether the precursor gas is an oxygen source or an aluminum source, the gas introduction time in any deposition stage of the Nth deposition process can be designed to be longer, and the gas flow rate in any deposition stage of the Nth deposition process can be smaller. Thus, the process parameters for the gas corresponding to the Nth deposition process are a long introduction time and a small gas flow rate, and the process parameters for the gas corresponding to the (N+1)th deposition process are a short introduction time and a large gas flow rate. This is beneficial to ensure that the gas reacts fully with the already formed film layer by using the combination of large and small values ​​for the introduction time and gas flow rate, thereby facilitating the formation of alumina film 112 with higher film quality.

[0125] In other examples, in conjunction with references Figure 6 and Figure 7Alternatively, the first deposition time can be controlled to be shorter than the second deposition time, and the first flow rate to be greater than the second flow rate. In other words, regardless of whether the precursor gas is an oxygen source or an aluminum source, the gas introduction time in any deposition stage of the Nth deposition process can be designed to be shorter, and the gas flow rate in any deposition stage of the Nth deposition process can be greater. Thus, the process parameters for the gas corresponding to the Nth deposition process are a short introduction time and a large gas flow rate, while the process parameters for the gas corresponding to the (N+1)th deposition process are a long introduction time and a small gas flow rate. This allows for the effective use of a combination of large and small values ​​for the introduction time and gas flow rate to ensure sufficient reaction between the gas and the already formed film, thereby facilitating the formation of alumina film 112 with higher film quality.

[0126] In some cases, refer to Figure 6 and Figure 7 The third introduction step includes introducing an oxygen source into the reaction chamber, and the fourth introduction step includes introducing an aluminum source into the reaction chamber; wherein, the oxygen source introduction duration in any deposition stage of the Nth deposition treatment is controlled to be greater than the oxygen source introduction duration in any deposition stage of the (N+1)th deposition treatment, and the oxygen source gas flow rate in any deposition stage of the Nth deposition treatment is less than the oxygen source gas flow rate in any deposition stage of the (N+1)th deposition treatment; the aluminum source introduction duration in any deposition stage of the Nth deposition treatment is controlled to be less than the aluminum source introduction duration in any deposition stage of the (N+1)th deposition treatment, and the aluminum source gas flow rate in any deposition stage of the Nth deposition treatment is greater than the aluminum source gas flow rate in any deposition stage of the (N+1)th deposition treatment.

[0127] This not only facilitates having a long oxygen source process parameter with a low gas flow rate for the Nth deposition treatment and a short oxygen source process parameter with a high gas flow rate for the (N+1)th deposition treatment, but also facilitates having a short aluminum source process parameter with a high gas flow rate for the Nth deposition treatment and a long aluminum source process parameter with a low gas flow rate for the (N+1)th deposition treatment. Furthermore, it facilitates having alternating long and short oxygen source induction times in the third and fourth induction steps, and alternating short and long aluminum source induction times in the third and fourth induction steps, thus ensuring that the total time consumed in a single deposition stage is essentially the same across different deposition treatments.

[0128] In some examples, in the Nth deposition process, the duration of the third infeed step is equal to the duration of the fourth infeed step. In other words, the long infeed duration of the oxygen source corresponding to the Nth deposition process is equal to the short infeed duration of the aluminum source corresponding to the Nth deposition process.

[0129] In one example, in the first deposition process, the duration of the third induction step, i.e., the oxygen source induction duration, can be 2s to 10s, for example, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s, or 10s; the duration of the fourth induction step, i.e., the aluminum source induction duration, can also be 2s to 10s. Furthermore, in the second deposition process, the duration of the third induction step, i.e., the oxygen source induction duration, can be 1s to 9s, for example, 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, or 9s; the duration of the fourth induction step, i.e., the aluminum source induction duration, can be 3s to 11s, for example, 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, or 11s.

[0130] In some examples, the gas flow rate of the oxygen source in the third inlet step of the Nth deposition process can be equal to the gas flow rate of the aluminum source in the fourth inlet step of the (N+1)th deposition process. In other words, the small gas flow rate of the oxygen source corresponding to the Nth deposition process is equal to the small gas flow rate of the aluminum source corresponding to the (N+1)th deposition process. Moreover, the gas flow rate of the aluminum source in the fourth inlet step of the Nth deposition process can be equal to the gas flow rate of the oxygen source in the third inlet step of the (N+1)th deposition process. In other words, the large gas flow rate of the oxygen source corresponding to the Nth deposition process is equal to the large gas flow rate of the aluminum source corresponding to the (N+1)th deposition process.

[0131] In one example, during the first deposition process, the oxygen source gas flow rate in the third introduction step can be 12 sccm to 20 sccm, for example, 12 sccm, 13 sccm, 14 sccm, 15 sccm, 16 sccm, 17 sccm, 18 sccm, 19 sccm, or 20 sccm, etc. During the first deposition process, the aluminum source gas flow rate in the fourth introduction step can be 14 sccm to 22 sccm, for example, 14 sccm, 15 sccm, 16 sccm, 17 sccm, 18 sccm, 19 sccm, 20 sccm, 21 sccm, or 22 sccm, etc. Furthermore, during the second deposition process, the oxygen source gas flow rate in the third introduction step can be 14 sccm to 22 sccm; and during the second deposition process, the aluminum source gas flow rate in the fourth introduction step can be 12 sccm to 20 sccm.

[0132] In some examples, the purging time of any fourth purging step in the Nth deposition process is controlled to be less than the purging time of any fourth purging step in the (N+1)th deposition process. Thus, as the alumina layer 102 preparation process progresses, it facilitates more thorough purging of byproducts or excess oxygen or aluminum sources generated during the alumina film 112 formation process, further ensuring a higher quality alumina layer 102 is ultimately formed.

[0133] In one example, N is 2, meaning that the alumina layer 102 is formed by two deposition processes. The purging time of any fourth purging step in the first deposition process can be 9s to 17s, for example, 9s, 10s, 11s, 12s, 13s, 14s, 15s, 16s or 17s, etc.; the purging time of any fourth purging step in the second deposition process can be 10s to 18s, for example, 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s or 18s, etc.

[0134] In one example, N is 2, meaning that the alumina layer 102 is formed by two deposition processes. The purging time of any third purging step in the first deposition process can be 9s to 17s; the purging time of any third purging step in the second deposition process can also be 9s to 17s.

[0135] In some embodiments, reference Figure 6 The alumina layer 102 formed in step S3 may include N stacked alumina films 112, where N is a positive integer greater than 1.

[0136] In some cases, the aluminum content in the Nth alumina film 112 can be higher than that in the (N+1)th alumina film 112. This is beneficial for increasing the density of fixed negative charges in the Nth alumina film 112, thereby facilitating the formation of a built-in electric field with a higher electric field strength. Moreover, it is beneficial for improving the structural stability of the Nth alumina film 112, for example, making the Nth alumina film 112 less prone to phase transition or decomposition, so as to maintain the high negative charge density and passivation effect stability of the Nth alumina film 112.

[0137] In other cases, the hydrogen content in the Nth alumina film 112 can be lower than that in the (N+1)th alumina film 112. This is beneficial for improving the hydrogen passivation effect of the (N+1)th alumina film 112 itself. Moreover, the subsequent alumina layer 102 may also promote the diffusion of a small amount of hydrogen from the (N+1)th alumina film 112 into the Nth alumina film 112 under high temperature conditions, thereby improving the hydrogen passivation effect of the Nth alumina film 112 itself.

[0138] In some other cases, along the first direction X, the thickness of the Nth alumina film 112 is less than the thickness of the (N+1)th alumina film 112; the first direction X is the thickness direction of the substrate 100. Thus, forming a thinner Nth alumina film 112 helps reduce the risk of microcracks or uneven thickness in different regions of the Nth alumina film 112, thereby further improving the film quality of the Nth alumina film 112 and providing a better interface foundation for the preparation of the (N+1)th alumina film 112.

[0139] In the above embodiments, during the processes of forming the first protective layer 101 in step S2, forming the alumina layer 102 in step S3, and forming the second protective layer 103 in step S4, the aluminum source provided may include at least one of alkyl aluminum compounds, aluminum halide sources, or aluminum-containing alkoxides.

[0140] It should be noted that during the formation of the first protective layer 101 in step S2 and the formation of the second protective layer 103 in step S4, aluminum is the main component in both the first protective layer 101 and the second protective layer 103. For example, the content of aluminum in the first protective layer 101 and / or the second protective layer 103 is greater than or equal to 90%. Based on this, due to the influence of the aluminum source including other elements besides aluminum, such as carbon or hydrogen contained in trimethylaluminum, the first protective layer 101 and / or the second protective layer 103 may contain hydrogen or carbon in addition to a large amount of aluminum. Due to the influence of the substrate 100, the first protective layer 101, which is closer to the substrate 100, may contain semiconductor elements similar to those in the substrate 100 in addition to a large amount of aluminum. Due to the influence of the alumina layer 102, the first protective layer 101 or the second protective layer 103, which is closer to the alumina layer 102, may also contain oxygen, similar to that in the alumina layer 102.

[0141] In some examples, the alkylaluminum compound may include at least one of trimethylaluminum or triethylaluminum. Trimethylaluminum can be directly introduced into the reaction chamber as a gaseous aluminum source.

[0142] In some examples, the aluminum halide source may include at least one of aluminum trichloride or aluminum triiodide.

[0143] In some examples, aluminum-containing alkoxides may include aluminum triisopropoxide.

[0144] In the above embodiments, during the process of forming the alumina layer 102 in step S3, the oxygen source provided may include at least one of ozone, water vapor, oxygen or hydrogen peroxide.

[0145] In the above embodiments, during the process of forming the first protective layer 101 in step S2, forming the alumina layer 102 in step S3, and forming the second protective layer 103 in step S4, the purging gas introduced may include at least one of the following gases that do not react with the aluminum source, oxygen source, and the formed alumina layer 102: nitrogen, argon, or helium.

[0146] Another embodiment of this disclosure provides a tandem battery, which includes a photovoltaic cell formed by the manufacturing method of the photovoltaic cell provided in the foregoing embodiments, or the photovoltaic cell provided in the foregoing embodiments. The tandem battery provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments will not be repeated here.

[0147] refer to Figure 8 , Figure 8 This is a partial cross-sectional schematic diagram of a tandem solar cell provided in another embodiment of the present disclosure. The tandem solar cell (TSC) includes: a bottom cell 104, which is a photovoltaic cell provided in the foregoing embodiment, or a photovoltaic cell formed by the preparation method of the photovoltaic cell provided in the foregoing embodiment; and a top cell 105, which is located on one side of the bottom cell 104.

[0148] In some embodiments, the top cell 105 may be one of perovskite solar cells, donor-acceptor cells, cadmium telluride (CdTe) photovoltaic cells, copper indium gallium selenide (CIGS) photovoltaic cells, or gallium arsenide (GaAs) photovoltaic cells.

[0149] In some embodiments, the top cell 105 may include: a first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer, and an antireflection layer stacked together. The first transport layer is directly opposite the bottom cell 104.

[0150] In some examples, the first transport layer can be either an electron transport layer or a hole transport layer, and the second transport layer can be either an electron transport layer or a hole transport layer.

[0151] In some embodiments, the bandgap width of the top cell 105 is wider than that of the bottom cell 104. Therefore, stacking the top cell 105 on top of the bottom cell 104 can give the stacked cell a wider spectral response range, thereby maximizing the utilization of solar energy and improving the efficiency of the stacked cell.

[0152] In some embodiments, the stacked battery may further include an intermediate connecting layer (not shown in the figure), which is connected between the bottom battery 104 and the top battery 105.

[0153] In some cases, the intermediate connecting layer is typically a tunnel junction or a very thin metal or transparent electrode composite layer. Optionally, the intermediate connecting layer can be a transparent conductive oxide, which has good optoelectronic properties, high photon transmittance, and high conductivity, thereby enabling the top cell 105 and the bottom cell 104 to maintain good ohmic contact.

[0154] In other cases, the electrodes in the photovoltaic cell that serves as the bottom cell 104 can also serve as an intermediate connecting layer for electrical connection with the top cell 105.

[0155] Another embodiment of this disclosure provides a photovoltaic module, which is formed by connecting multiple photovoltaic cells provided in the foregoing embodiments, or by connecting photovoltaic cells formed by the preparation methods of multiple photovoltaic cells provided in the foregoing embodiments, or by connecting multiple tandem cells provided in the foregoing embodiments. The photovoltaic module provided in another embodiment of this disclosure will be described below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments will not be repeated here.

[0156] Reference Figures 1 to 10 Photovoltaic module: a battery string, which is formed by connecting multiple photovoltaic cells 40 provided in the foregoing embodiments, or by connecting multiple photovoltaic cells 40 formed by the preparation method of photovoltaic cells provided in the foregoing embodiments, or by connecting multiple stacked cells provided in the foregoing embodiments; an encapsulating film 41, used to cover the surface of the battery string; a cover plate 42, used to cover the surface of the encapsulating film 41 facing away from the battery string.

[0157] in, Figure 9 A partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in another embodiment of the present disclosure; Figure 10 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of the present disclosure.

[0158] In some embodiments, the photovoltaic cell 40 includes, but is not limited to, one or any combination of PERC cells (Passivated Emitter RearCell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology), thin-film solar cells, and tandem cells. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0159] In some embodiments, the photovoltaic cell 40 can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, the multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0160] In some embodiments, the photovoltaic cells 40 are electrically connected in the form of a single cell or multiple segments to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The photovoltaic cells 40 can be a single cell or a sliced ​​cell, where a sliced ​​cell refers to a cell formed by cutting a complete single cell.

[0161] In some embodiments, in conjunction with reference Figure 9 and Figure 10 Multiple photovoltaic cells 40 can be electrically connected to each other via conductive strips 43. Figure 9 and Figure 10 This illustration only shows one positional relationship between photovoltaic cells 40, where the electrodes of the photovoltaic cells 40 with the same polarity are arranged in the same direction, or in other words, the electrodes of each photovoltaic cell 40 with positive polarity are arranged facing the same side, so that the conductive strip 43 connects different sides of two adjacent photovoltaic cells 40 respectively. In other embodiments, the photovoltaic cells can also be arranged with electrodes of different polarities facing the same side, that is, the electrodes of multiple adjacent photovoltaic cells are arranged in the order of first polarity, second polarity, and first polarity respectively, then the conductive strip connects the same side of two adjacent photovoltaic cells.

[0162] In some embodiments, there may be no gap between adjacent photovoltaic cells, that is, adjacent photovoltaic cells may overlap each other.

[0163] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the photovoltaic cell 40, and the second encapsulating layer covers the other of the front or back sides of the photovoltaic cell 40. Specifically, at least one of the first or second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer can also be an EP film, an EPE film, or a PVP film. Here, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film + POE film + EVA film; and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0164] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0165] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0166] In some embodiments, the photovoltaic cell 40 may be a cell with a main grid or a cell without a main grid.

[0167] In some cases, when the photovoltaic cell 40 is a busbar cell, the surface of the photovoltaic cell 40 has multiple main grids spaced apart along the second direction Y and multiple sub-grids spaced apart along the third direction Z. The main grid includes main grid connection lines and pads located on the main grid connection lines. During the process of constructing a cell string using the photovoltaic cells 40, the conductive strip 43 is electrically connected to at least one main grid on each of two adjacent photovoltaic cells 40. The conductive strip 43 can be electrically connected to the main grid by soldering to the pads, or it can be pre-fixed to the main grid with adhesive dots, and the electrical connection with the main grid is achieved by the fusion of the adhesive dots and the deformation of the conductive strip 43 during the lamination process.

[0168] It should be noted that the first direction X, the second direction Y, and the third direction Z intersect each other pairwise. In one example, the first direction X, the second direction Y, and the third direction Z can be orthogonal to each other. In practical applications, the angle formed by any two of the first, second, and third directions can be either acute or obtuse.

[0169] The intersection of the first direction X and the second direction Y includes the following scenarios: the first direction X and the second direction Y are orthogonal; the included angle is obtuse; or the included angle is acute. In some examples, the included angle of the first direction X and the second direction Y can be between 10° and 90°, for example, 10°, 20°, 45°, 55°, 70°, 82°, or 90°. In some specific examples, the included angle of the first direction X and the second direction Y can also be between 45° and 90°. It should be noted that the intersection of the second direction Y and a third direction Z, and the intersection of the first direction X and a third direction Z, are similar to the cases of the intersection of the first direction X and the second direction Y described above, and will not be elaborated further here.

[0170] In other cases, where the photovoltaic cell 40 is a gridless cell, the surface of the photovoltaic cell 40 has multiple sub-grids arranged at Z intervals along the third direction. During the process of constructing a cell string using the photovoltaic cells 40, the conductive strip 43 is electrically connected to the multiple sub-grids on each of two adjacent photovoltaic cells 40. The conductive strip 43 can be fixed at a specific position above the photovoltaic cell 40 by adhesive dots, and then the electrical connection between the conductive strip 43 and the sub-grids is achieved by the fusion of the adhesive dots and the deformation of the conductive strip 43 during the lamination process.

[0171] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized by, The application relates to a substrate and a method for manufacturing the same. The substrate comprises: a substrate; a first protective layer on a surface of the substrate; an aluminum oxide layer on a surface of the first protective layer away from the substrate; a second protective layer on a surface of the aluminum oxide layer away from the first protective layer; 2. The photovoltaic cell of claim 1, wherein, wherein the first protective layer and the second protective layer both contain aluminum, and the content of aluminum in the first protective layer and the second protective layer is greater than 90%, and the content of aluminum in the aluminum oxide layer is less than 90%.

3. The photovoltaic cell of claim 1, wherein, The first protective layer and the second protective layer further contain hydrogen and carbon. The aluminum oxide layer comprises N layers of aluminum oxide films stacked together, and N is a positive integer greater than 1; 4. The photovoltaic cell of claim 1, wherein, wherein the content of aluminum in the Nth layer of the aluminum oxide films is higher than the content of aluminum in the (N+1)th layer of the aluminum oxide films; and / or, the content of hydrogen in the Nth layer of the aluminum oxide films is lower than the content of hydrogen in the (N+1)th layer of the aluminum oxide films; and / or, along a first direction, the thickness of the Nth layer of the aluminum oxide films is less than the thickness of the (N+1)th layer of the aluminum oxide films; the first direction is the thickness direction of the substrate.

5. A method of producing a photovoltaic cell, characterized by, Along the first direction, the thickness of the first protective layer is 0.3-1 nm; and / or, along the first direction, the thickness of the second protective layer is 0.3-1 nm; the first direction is the thickness direction of the substrate. The application further relates to a method for manufacturing the substrate. The method comprises the following steps: providing a substrate and placing the substrate in a reaction chamber; performing a first pretreatment on the substrate by introducing an aluminum source into the reaction chamber to form a first protective layer on a surface of the substrate; 6. The method of claim 5, wherein the step of depositing the transparent conductive layer is performed by sputtering. forming an aluminum oxide layer on a surface of the first protective layer away from the substrate; performing a second pretreatment on the aluminum oxide layer by introducing an aluminum source into the reaction chamber again to form a second protective layer on a surface of the aluminum oxide layer away from the substrate; wherein the first protective layer and the second protective layer both contain aluminum, and the content of aluminum in the first protective layer and the second protective layer is greater than 90%, and the content of aluminum in the aluminum oxide layer is less than 90%.

7. The method of claim 6, wherein the method further comprises the step of depositing a transparent conductive layer on the transparent substrate prior to the step of depositing the first layer of semiconductor material. The first pretreatment comprises a plurality of first introduction stages, and any one of the first introduction stages comprises a first introduction step and a first purging step connected in sequence; the first introduction step comprises introducing an aluminum source into the reaction chamber, and the first purging step comprises introducing a purging gas into the reaction chamber; 8. The method of claim 5, wherein the step of forming the photoactive layer is performed by depositing a solution of a photoactive material onto the substrate. The second pretreatment comprises a plurality of second introduction stages, and any one of the second introduction stages comprises a second introduction step and a second purging step connected in sequence; the second introduction step comprises introducing an aluminum source into the reaction chamber, and the second purging step comprises introducing a purging gas into the reaction chamber. The duration of the introduction of the aluminum source in the first introduction step is the same as the duration of the introduction of the aluminum source in the second introduction step; and / or, the gas flow of the aluminum source in the first introduction step is the same as the gas flow of the aluminum source in the second introduction step; and / or, the number of cycles of the first introduction stage is the same as the number of cycles of the second introduction stage; and / or, the purging duration of the first purging step is the same as the purging duration of the second purging step. The step of forming the aluminum oxide layer comprises: forming the aluminum oxide layer on a surface of the first protective layer distal to the substrate by N deposition processes, any of the deposition processes comprising a plurality of deposition stages, N being an integer greater than 1 and less than 6; wherein any of the deposition stages comprises sequentially connected third introducing step, third purging step, fourth introducing step and fourth purging step; one of the third introducing step and the fourth introducing step comprises introducing an oxygen source into the reaction chamber, the other of the third introducing step and the fourth introducing step comprises introducing an aluminum source into the reaction chamber; the third purging step and the fourth purging step comprise introducing a purging gas into the reaction chamber.

9. The method of claim 8, wherein the method further comprises the step of depositing a transparent conductive layer on the transparent substrate prior to the step of depositing the first layer of transparent conductive material. The number of cycles of the deposition stages in the Nth deposition process is less than the number of cycles of the deposition stages in the (N+1)th deposition process.

10. The method of claim 8, wherein the method further comprises: The duration of introducing the precursor gas in any of the deposition stages of the Nth deposition process is a first duration, and the duration of introducing the precursor gas in any of the deposition stages of the (N+1)th deposition process is a second duration; The gas flow rate of the precursor gas in any of the deposition stages of the Nth deposition process is a first flow rate, and the gas flow rate of the precursor gas in any of the deposition stages of the (N+1)th deposition process is a second flow rate; wherein the precursor gas is an oxygen source or an aluminum source, the first duration is controlled to be greater than the second duration and the first flow rate is controlled to be less than the second flow rate, or the first duration is controlled to be less than the second duration and the first flow rate is controlled to be greater than the second flow rate.

11. The method of claim 8, wherein the method further comprises: The third introducing step comprises introducing an oxygen source into the reaction chamber, and the fourth introducing step comprises introducing an aluminum source into the reaction chamber; wherein the duration of introducing the oxygen source in any of the deposition stages of the Nth deposition process is controlled to be greater than the duration of introducing the oxygen source in any of the deposition stages of the (N+1)th deposition process, and the gas flow rate of the oxygen source in any of the deposition stages of the Nth deposition process is controlled to be less than the gas flow rate of the oxygen source in any of the deposition stages of the (N+1)th deposition process; the duration of introducing the aluminum source in any of the deposition stages of the Nth deposition process is controlled to be less than the duration of introducing the aluminum source in any of the deposition stages of the (N+1)th deposition process, and the gas flow rate of the aluminum source in any of the deposition stages of the Nth deposition process is controlled to be greater than the gas flow rate of the aluminum source in any of the deposition stages of the (N+1)th deposition process.

12. The method of claim 11, wherein the method further comprises: In the Nth deposition process, the duration of the third introducing step is equal to the duration of the fourth introducing step.

13. The method of claim 11, wherein the method further comprises: The purging duration of any of the fourth purging steps of the Nth deposition process is controlled to be less than the purging duration of any of the fourth purging steps of the (N+1)th deposition process.

14. A stacked battery characterized by comprising: comprising: a bottom cell, the bottom cell being a photovoltaic cell as claimed in any of claims 1 to 4, or being a photovoltaic cell formed by the method of producing a photovoltaic cell as claimed in any of claims 5 to 13; a top cell, the top cell being located on one side of the bottom cell.

15. A photovoltaic module, characterized by comprising: a battery string formed by connecting a plurality of photovoltaic cells according to any one of claims 1 to 4, or a photovoltaic cell formed by the method for producing a photovoltaic cell according to any one of claims 5 to 13, or a plurality of stacked cells according to claim 14; an encapsulant film for covering a surface of the battery string; a cover plate for covering a surface of the encapsulant film facing away from the battery string.

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