Solar cell and method of manufacturing the same

Abstract

The present invention provides a method for manufacturing a solar cell and a solar cell manufactured by the method. The method includes a step of forming a first doped amorphous silicon layer on a substrate, a step of crystallizing the first doped amorphous silicon layer to form a first doped polycrystalline silicon layer, a step of forming an intrinsically polycrystalline silicon layer on the first doped polycrystalline silicon layer, and a step of forming a second doped polycrystalline silicon layer on the intrinsically polycrystalline silicon layer with a polarity opposite to that of the first doped polycrystalline silicon layer.

Description

[Technical Field]

[0001] This invention relates to a solar cell, particularly a crystalline solar cell. [Previous Technology]

[0002] In related technologies, crystalline solar cells have been manufactured using semiconductor substrates such as silicon wafers. Specifically, in related technologies, crystalline solar cells have been manufactured by forming an n-type semiconductor layer on one surface of a silicon wafer and a p-type semiconductor layer on the other surface of the silicon wafer.

[0003] However, when silicon wafers are used in the manner described above, it is difficult to manufacture solar cells with a large area. Furthermore, because silicon wafers increase the thickness of solar cells, it is difficult to apply solar cells to products that require thin thickness. [Summary of the Invention]

[0004] Technical Issues

[0005] The present invention aims to solve the above-mentioned problems and to provide a crystalline solar cell using a substrate with a thin thickness rather than a semiconductor substrate such as a silicon wafer, and a method for manufacturing the crystalline solar cell.

[0006] Technical means

[0007] To achieve the above objective, the present invention provides a method for manufacturing a solar cell, the method comprising: a step of forming a first doped amorphous silicon layer on a substrate; a step of crystallizing the first doped amorphous silicon layer to form a first doped polycrystalline silicon layer; a step of forming an intrinsically polycrystalline silicon layer on the first doped polycrystalline silicon layer; and a step of forming a second doped polycrystalline silicon layer on the intrinsically polycrystalline silicon layer with a polarity opposite to that of the first doped polycrystalline silicon layer.

[0008] The step of forming an intrinsically polycrystalline silicon layer may include a process of directly depositing an intrinsically polycrystalline silicon layer by using a first doped polycrystalline silicon layer as a seed layer.

[0009] The amount of hydrogen supplied in the step of forming the intrinsically polycrystalline silicon layer may be higher than the amount of hydrogen supplied in the step of forming the first doped amorphous silicon layer.

[0010] The ratio of the hydrogen content supplied in the step of forming the intrinsically polycrystalline silicon layer to the content of the silicon-containing source gas may be higher than the ratio of the hydrogen content supplied in the step of forming the first doped amorphous silicon layer to the content of the silicon-containing source gas.

[0011] The step of forming the second doped polycrystalline silicon layer may include a process of directly depositing the second doped polycrystalline silicon layer by using an intrinsic polycrystalline silicon layer as a seed layer.

[0012] The hydrogen content supplied in the step of forming the second doped polycrystalline silicon layer may be higher than the hydrogen content supplied in the step of forming the first doped amorphous silicon layer.

[0013] The ratio of the hydrogen content supplied in the step of forming the second doped polycrystalline silicon layer to the content of the silicon-containing source gas may be higher than the ratio of the hydrogen content supplied in the step of forming the first doped amorphous silicon layer to the content of the silicon-containing source gas.

[0014] The ratio of the hydrogen content supplied in the step of forming the second doped polycrystalline silicon layer to the content of the silicon-containing source gas can be equal to the ratio of the hydrogen content supplied in the step of forming the intrinsic polycrystalline silicon layer to the content of the silicon-containing source gas.

[0015] This method may further include a step of forming a perovskite solar cell comprising a first conductive charge transport layer, a light absorption layer and a second conductive charge transport layer on a second doped polycrystalline silicon layer.

[0016] This method may further include a step of forming a barrier layer between the glass substrate and the first doped amorphous silicon layer prior to the step of forming the first doped amorphous silicon layer.

[0017] The substrate may be formed of glass or plastic.

[0018] The present invention provides a solar cell comprising a substrate, a first doped polycrystalline silicon layer provided on a glass substrate, an intrinsically polycrystalline silicon layer provided on the first doped polycrystalline silicon layer, and a second doped polycrystalline silicon layer located on the intrinsically polycrystalline silicon layer and having a polarity opposite to that of the first doped polycrystalline silicon layer.

[0019] This solar cell may further comprise a perovskite solar cell located on a second doped polycrystalline silicon layer and comprising a first conductive charge transport layer, a light absorption layer and a second conductive charge transport layer.

[0020] This solar cell may further include a barrier layer located between the glass substrate and the first doped polycrystalline silicon layer.

[0021] The substrate may be formed of glass or plastic.

[0022] Beneficial effects

[0023] The following effects can be achieved according to the present invention.

[0024] According to one embodiment of the present invention, a first doped amorphous silicon layer can be formed on a substrate, followed by a crystallization process to form a first doped polycrystalline silicon layer. The intrinsically polycrystalline silicon layer can be directly deposited by using the first doped polycrystalline silicon layer as a seed layer, and a second doped polycrystalline silicon layer can be directly deposited by using the intrinsically polycrystalline silicon layer as a seed layer. Therefore, a thin-thick glass or plastic substrate can be used instead of a semiconductor substrate such as a silicon wafer, thereby enabling the manufacture of solar cells with large areas and also enabling the implementation of solar cells with thin thicknesses. Consequently, there is the advantage that solar cells can be applied to various products that can be installed in vehicles, building facades, etc.

Implementation Method

[0026] The advantages, features, and implementation methods of the present invention will be illustrated by the following embodiments described with reference to the related drawings. However, the present invention may be implemented in different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided instead to make the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art. Furthermore, the invention is defined only by the scope of the claims.

[0027] The quantities, angles, proportions, dimensions, and shapes disclosed in the drawings to describe embodiments of the present invention are merely examples, and therefore the present invention is not limited to the details shown. Similar reference numerals throughout the text denote similar elements. In the following description, detailed descriptions of related prior art will be omitted when they are deemed unnecessary to obscure the focus of the present invention. In the use of "comprising," "having," and "including" in this specification, another component may be added unless "only" is used. Unless otherwise stated, singular forms may include plural forms.

[0028] When interpreting components, even if they are not described in detail, they should still be interpreted as including a range of error.

[0029] When describing positional relationships, if the positional relationship between two components is described by terms such as "above", "above", "below" and "beside", unless "direct" or "direct" is used, one or more other components may be placed between the two components.

[0030] When describing temporal relationships, if the time sequence is described by terms such as "after", "following", "next" and "before", discontinuous cases may be included unless "immediately after" or "directly" is used.

[0031] It will be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited to these terms. These terms are only used to identify elements. For example, without departing from the scope of the invention, a first element can be represented as a second element, and similarly, a second term can be represented as a first term.

[0032] The features of the various embodiments of the present invention may be partially or entirely coupled or combined with each other, and may interact with each other in various ways and be technically driven in a manner that can be fully understood by those skilled in the art. Embodiments of the present invention may be implemented independently of each other, or may be implemented in a commonly related relationship.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the relevant drawings.

[0034] Figures 1A to 1D are process cross-sectional views of a solar cell according to an embodiment of the present invention.

[0035] First, as shown in FIG1A, a first doped amorphous silicon layer 210a is formed on substrate 100.

[0036] The substrate 100 is formed of glass or plastic rather than a semiconductor substrate such as a silicon wafer.

[0037] The first doped amorphous silicon layer 210a may be formed by P-doped amorphous silicon or by N-doped amorphous silicon.

[0038] The first doped amorphous silicon layer 210a can be formed by a thin film deposition process such as chemical vapor deposition (CVD). In this case, the first doped amorphous silicon layer 210a can be formed by using a silicon-containing source gas such as silane gas (SiH4), hydrogen gas (H2), and a material containing p-type dopant or n-type dopant.

[0039] Subsequently, as shown in FIG1B, a first doped polycrystalline silicon layer 210 is formed by crystallizing the first doped amorphous silicon layer 210a.

[0040] The crystallization process may include a laser annealing process, but is not limited to it.

[0041] The amorphous silicon is crystallized by laser annealing on the first doped amorphous silicon layer 210a, and polycrystalline silicon is formed therefrom, thereby obtaining the first doped polycrystalline silicon layer 210.

[0042] Subsequently, as shown in FIG1C, an intrinsic polycrystalline silicon layer 220 is formed on the first doped polycrystalline silicon layer 210.

[0043] The first doped polycrystalline silicon layer 210 can be used as a seed layer, and thus the intrinsic polycrystalline silicon layer 220 can be formed by a one-step process of direct deposition without undergoing a two-step process of crystallizing the amorphous silicon layer after deposition.

[0044] In detail, by using a plasma-enhanced chemical vapor deposition (PECVD) process, the intrinsic polycrystalline silicon layer 220 can be directly deposited on the first doped polycrystalline silicon layer 210.

[0045] The intrinsic polycrystalline silicon layer 220 can be formed from a silicon-containing source gas such as silane gas (SiH4) and hydrogen gas (H2). In this case, when the hydrogen gas (H2) is maintained at a high flow rate, the polycrystalline silicon can be grown more easily due to the effect of repeated deposition / etching / deposition of hydrogen.

[0046] Therefore, the flow rate of hydrogen (H2) supplied when forming the intrinsically polycrystalline silicon layer 220 is higher than the flow rate of hydrogen (H2) supplied when forming the first doped amorphous silicon layer 210a. Furthermore, the ratio of hydrogen (H2) content to the content of silicon-containing source gases such as silane gas (SiH4) is higher when forming the intrinsically polycrystalline silicon layer 220 than when forming the first doped amorphous silicon layer 210a.

[0047] Subsequently, as shown in FIG1D, a second doped polycrystalline silicon layer 230 is formed on the intrinsic polycrystalline silicon layer 220.

[0048] The intrinsic polycrystalline silicon layer 220 can serve as a seed layer, and thus a second doped polycrystalline silicon layer 230 is also formed by using a one-step direct deposition process.

[0049] The second doped polycrystalline silicon layer 230 can be formed by using a silicon-containing source gas such as silane gas (SiH4), hydrogen gas (H2), and a material containing p-type or n-type dopants. In this case, as with the intrinsic polycrystalline silicon layer 220, the second doped polycrystalline silicon layer 230 can be formed more easily when hydrogen gas (H2) is maintained at a high flow rate.

[0050] Therefore, the flow rate of hydrogen (H2) supplied when forming the second doped polycrystalline silicon layer 230 is higher than the flow rate of hydrogen (H2) supplied when forming the first doped amorphous silicon layer 210a. Furthermore, the ratio of hydrogen (H2) content to the content of silicon-containing source gases such as silane gas (SiH4) is higher when forming the second doped polycrystalline silicon layer 230 than when forming the first doped amorphous silicon layer 210a.

[0051] Furthermore, the ratio of hydrogen (H2) content to the content of silicon-containing source gas, such as silane gas (SiH4), may be the same when forming the second doped polycrystalline silicon layer 230 and when forming the intrinsic polycrystalline silicon layer 220, but may be different depending on the circumstances.

[0052] The polarity of the second doped polycrystalline silicon layer 230 is opposite to that of the first doped polycrystalline silicon layer 210. That is, when the first doped polycrystalline silicon layer 210 is formed of P-doped polycrystalline silicon, the second doped polycrystalline silicon layer 230 is formed of N-doped polycrystalline silicon, and when the first doped polycrystalline silicon layer 210 is formed of N-doped polycrystalline silicon, the second doped polycrystalline silicon layer 230 is formed of P-doped polycrystalline silicon.

[0053] As described above, according to an embodiment of the present invention, a first doped amorphous silicon layer 210a can be formed on the substrate 100, followed by a crystallization process to form a first doped polycrystalline silicon layer 210. The intrinsic polycrystalline silicon layer 220 can be directly deposited by using the first doped polycrystalline silicon layer 210 as a seed layer, and the second doped polycrystalline silicon layer 230 can be directly deposited by using the intrinsic polycrystalline silicon layer 220 as a seed layer. Therefore, a thin-thickness glass or plastic semiconductor substrate, rather than a silicon wafer, can be used as the substrate 100, thereby enabling the manufacture of solar cells with large areas and also allowing the implementation of solar cells with thin thicknesses. Therefore, there is the advantage that solar cells can be applied to various products that can be installed in vehicles, building facades, etc.

[0054] Figures 2A to 2E are process cross-sectional views of a solar cell according to another embodiment of the present invention.

[0055] Figures 2A to 2D are the same as those 1A to 1D above, so they will not be described again.

[0056] As shown in Figure 2E, after the process in Figure 2D, a buffer layer 300 is formed on the second doped polycrystalline silicon layer 230, and a perovskite solar cell 400 is formed on the buffer layer 300.

[0057] A buffer layer 300 is provided between the perovskite solar cell 400 and the polycrystalline solar cell comprising a first doped polycrystalline silicon layer 210, an intrinsic polycrystalline silicon layer 220 and a second doped polycrystalline silicon layer 230, and thus the solar cell according to an embodiment of the present invention has a structure of a stacked solar cell based on a tunnel junction.

[0058] Preferably, the buffer layer 300 is made of a material that allows light with a long wavelength to pass through the perovskite solar cell 400 and be incident on the polycrystalline silicon solar cell without loss. For example, the buffer layer 300 may be formed of a transparent conductive oxide, a carbon conductive material, a metallic material, or a conductive polymer, and may be doped with n-type or p-type dopants as appropriate. However, the buffer layer 300 may be omitted as appropriate.

[0059] The process of forming the perovskite solar cell 400 may include a process of forming a first conductive charge transport layer 410 on the buffer layer 300, a process of forming a light absorption layer 420 on the first conductive charge transport layer 410, and a process of forming a second conductive charge transport layer 430 on the light absorption layer 420.

[0060] The process of forming the first conductive charge transport layer 410 and the process of forming the second conductive charge transport layer 430 through a thin film deposition process such as evaporation may each include a process of forming an electron transport layer (ETL) or a hole transport layer (HTL) containing organic materials.

[0061] In detail, when the second doped polycrystalline silicon layer 230 is formed of N-doped polycrystalline silicon, the first conductive charge transport layer 410 includes a hole transport layer (HTL), and the second conductive charge transport layer 430 includes an electron transport layer (ETL).

[0062] Alternatively, when the second doped polycrystalline silicon layer 230 is formed of P-doped polycrystalline silicon, the first conductive charge transport layer 410 includes an electron transport layer (ETL), and the second conductive charge transport layer 430 includes a hole transport layer (HTL).

[0063] The hole transport layer may contain various p-type organic materials, such as spiro-MeO-TAD, spiro-TTB, polyaniline, polyphenols, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), PEDOT-PSS, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and poly(3-hexylthiophene-2,5-diyl), or may contain compounds containing various p-type organic or inorganic materials and various p-type metal oxides such as nickel oxide, molybdenum oxide, vanadium oxide, tungsten oxide, or copper oxide, as known to those skilled in the art.

[0064] The electron transport layer may contain compounds containing various n-type organic or inorganic materials and n-type organic materials such as bath copper (BCP), fullerene (C60) or methyl phenyl-C61-butyrate (PCBM), as known to those skilled in the art, or compounds containing various n-type metal oxides such as zinc oxide, c-TiO2 / mp-TiO2, tin dioxide or indium zinc oxide.

[0065] The process of forming the light-absorbing layer 420 may include a process known to those skilled in the art to form a perovskite compound through a thin film deposition process such as a solution process or a chemical vapor deposition (CVD) process.

[0066] Figures 3A to 3E are process cross-sectional views of a solar cell according to another embodiment of the present invention.

[0067] First, as shown in FIG3A, a barrier layer 150 is formed on the substrate 100.

[0068] The substrate 100 is formed of glass or plastic rather than a semiconductor substrate such as a silicon wafer.

[0069] The barrier layer 150 prevents the compound of the substrate 100 from penetrating into the silicon layer during the deposition process described below. Furthermore, the barrier layer 150 performs the encapsulation function of preventing external water or oxygen from penetrating into the solar cell through the substrate 100.

[0070] The barrier layer 150 may be formed of inorganic insulating materials, such as silicon oxide, silicon nitride, metal oxides or metal nitrides containing metals such as aluminum, and may be formed by thin film deposition processes such as chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0071] Subsequently, as shown in FIG3B, a first doped amorphous silicon layer 210a is formed on the barrier layer 150.

[0072] The process for forming the first doped amorphous silicon layer 210a is the same as that in Figure 1A above, so it will not be described again.

[0073] Subsequently, as shown in FIG3C, a first doped polycrystalline silicon layer 210 is formed by crystallizing the first doped amorphous silicon layer 210a.

[0074] The process for forming the first doped polycrystalline silicon layer 210 is the same as that in Figure 1B above, so it will not be described again.

[0075] Subsequently, as shown in FIG3D, an intrinsic polycrystalline silicon layer 220 is formed on the first doped polycrystalline silicon layer 210.

[0076] The process for forming the intrinsically polycrystalline silicon layer 220 is the same as that in Figure 1C above, so it will not be described again.

[0077] Subsequently, as shown in FIG3E, a second doped polycrystalline silicon layer 230 is formed on the intrinsic polycrystalline silicon layer 220.

[0078] The process for forming the second doped polycrystalline silicon layer 230 is the same as that in Figure 1D above, so it will not be described again.

[0079] Figures 4A to 4F are process cross-sectional views of a solar cell according to another embodiment of the present invention.

[0080] Figures 4A to 4E are the same as those 3A to 3E above, so they will not be described again.

[0081] As shown in Figure 4F, after the process in Figure 4E, a buffer layer 300 is formed on the second doped polycrystalline silicon layer 230, and a perovskite solar cell 400 is formed on the buffer layer 300.

[0082] The process for forming the buffer layer 300 and the process for forming the perovskite solar cell 400 are the same as those in Figure 2E above, so they will not be described again.

[0083] The embodiments of the present invention have been described in detail above with reference to the relevant drawings. However, the present invention is not limited to the embodiments and can be modified in various ways without departing from the technical spirit of the present invention. Therefore, it should be understood that the above embodiments are exemplary and not restrictive in various respects. It should be explained that the scope of the present invention is defined only by the following claims and not by the implementation methods, and the meaning and scope of the claims and all variations or modifications derived from their equivalent concepts are included in the scope of the present invention. [Simplified Explanation of the Diagram]

[0025] Figures 1A to 1D are process cross-sectional views of a solar cell according to an embodiment of the present invention. Figures 2A to 2E are process cross-sectional views of a solar cell according to another embodiment of the present invention. Figures 3A to 3E are process cross-sectional views of a solar cell according to another embodiment of the present invention. Figures 4A to 4F are process cross-sectional views of a solar cell according to another embodiment of the present invention.

Claims

1. A method for manufacturing a solar cell, the method comprising: a step of forming a first doped amorphous silicon layer on a glass substrate; a step of crystallizing the first doped amorphous silicon layer to form a first doped polycrystalline silicon layer by a laser annealing process; a step of forming a naturally polycrystalline silicon layer on the first doped polycrystalline silicon layer; and a step of forming a second doped polycrystalline silicon layer on the naturally polycrystalline silicon layer with a polarity opposite to that of the first doped polycrystalline silicon layer; wherein the formation of The step of forming the intrinsically polycrystalline silicon layer includes a process of directly depositing the intrinsically polycrystalline silicon layer by using the first doped polycrystalline silicon layer as a seed layer; wherein the step of forming the second doped polycrystalline silicon layer includes a process of directly depositing the second doped polycrystalline silicon layer by using the intrinsically polycrystalline silicon layer as a seed layer; wherein the hydrogen content supplied in the step of forming the intrinsically polycrystalline silicon layer is higher than the hydrogen content supplied in the step of forming the first doped amorphous silicon layer; The hydrogen content supplied in the step of forming the second doped polycrystalline silicon layer is higher than the hydrogen content supplied in the step of forming the first doped amorphous silicon layer; the ratio of the hydrogen content supplied in the step of forming the intrinsic polycrystalline silicon layer to the silicon-containing source gas content is higher than the ratio of the hydrogen content supplied in the step of forming the first doped amorphous silicon layer to the silicon-containing source gas content; and the ratio of the hydrogen content supplied in the step of forming the second doped polycrystalline silicon layer to the silicon-containing source gas content is higher than the ratio of the hydrogen content supplied in the step of forming the first doped amorphous silicon layer to the silicon-containing source gas content.

2. The method as claimed in claim 1, wherein the ratio of the amount of hydrogen supplied in the step of forming the second doped polycrystalline silicon layer to the amount of silicon-containing source gas is equal to the ratio of the amount of hydrogen supplied in the step of forming the intrinsic polycrystalline silicon layer to the amount of silicon-containing source gas.

3. The method as described in claim 1 further includes a step of forming a perovskite solar cell comprising a first conductive charge transport layer, a light absorption layer and a second conductive charge transport layer on the second doped polycrystalline silicon layer.

4. The method as described in claim 1 further includes a step of forming a barrier layer between the glass substrate and the first doped amorphous silicon layer prior to the step of forming the first doped amorphous silicon layer.

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