Perovskite solar cell and method of manufacturing the same

Abstract

The present invention provides a solar cell comprising a light-absorbing layer comprising a perovskite compound; and an electron transport layer provided on a first surface of the light-absorbing layer, wherein the electron transport layer comprises a first electron transport layer provided on the first surface of the light-absorbing layer and a second electron transport layer provided on the first electron transport layer, wherein the first electron transport layer comprises an inorganic metal nitride and the second electron transport layer comprises an inorganic metal oxynitride; and a method for manufacturing the solar cell.

Description

Technical Field

[0001] This invention relates to a perovskite solar cell and a method for manufacturing the same, particularly an electron transport layer for a perovskite solar cell. Prior Technology

[0002] A perovskite solar cell comprises a light-absorbing layer containing a perovskite compound, an electron transport layer on one side of the light-absorbing layer, and a hole transport layer on the other side of the light-absorbing layer.

[0003] Traditionally, a structure consisting of sequentially stacked C60 organic material layers and metal oxide layers is used as the electron transport layer. However, in this structure, there is a problem of the metal oxide layer penetrating the C60 organic layer and the perovskite compound constituting the light-absorbing layer being oxidized, thereby reducing the efficiency of the solar cell. Summary of the Invention

[0004] [Technical Issues]

[0005] The present invention aims to solve the above-mentioned problems and to provide a solar cell having an electron transport layer capable of preventing oxidation of the perovskite compound constituting the light absorption layer, as well as a method for manufacturing the same.

[0006] [Technical means]

[0007] To achieve the above objectives, one embodiment of the present invention provides a solar cell comprising a light-absorbing layer comprising a perovskite compound; and an electron transport layer provided on a first surface of the light-absorbing layer, wherein the electron transport layer comprises a first electron transport layer provided on the first surface of the light-absorbing layer and a second electron transport layer provided on the first electron transport layer, and wherein the first electron transport layer comprises an inorganic metal nitride and the second electron transport layer comprises an inorganic metal oxynitride, or the first electron transport layer comprises an inorganic metal sulfide and the second electron transport layer comprises an inorganic metal oxynitride.

[0008] Another embodiment of the present invention provides a solar cell comprising a light-absorbing layer comprising a perovskite compound; and an electron transport layer provided on a first surface of the light-absorbing layer, wherein the electron transport layer comprises a first electron transport layer provided on the first surface of the light-absorbing layer and a third electron transport layer provided on the first electron transport layer, and wherein the first electron transport layer comprises an inorganic metal nitride or an inorganic metal sulfide, and the third electron transport layer comprises an inorganic metal oxide.

[0009] Another embodiment of the present invention provides a method for manufacturing a solar cell, comprising forming a light-absorbing layer comprising a perovskite compound; and forming an electron transport layer on a first surface of the light-absorbing layer, wherein forming the electron transport layer comprises: forming an electron transport precursor layer comprising an inorganic metal nitride or an inorganic metal sulfide, and performing an oxygen plasma treatment on the electron transport precursor layer to form a first electron transport layer comprising an inorganic metal nitride or an inorganic metal sulfide and a second electron transport layer comprising an inorganic metal oxynitride or an inorganic metal sulfide.

[0010] Another embodiment of the present invention provides a method for manufacturing a solar cell, comprising forming a light-absorbing layer comprising a perovskite compound; and forming an electron transport layer on a first surface of the light-absorbing layer, wherein forming the electron transport layer comprises: forming an electron transport precursor layer comprising an inorganic metal nitride or an inorganic metal sulfide, and performing an oxygen plasma treatment on the electron transport precursor layer to form a first electron transport layer comprising an inorganic metal nitride or an inorganic metal sulfide and a third electron transport layer comprising an inorganic metal oxide.

[0011] [Beneficial effects]

[0012] According to the present invention, the following effects can be achieved.

[0013] According to one embodiment of the present invention, an electron transport precursor layer composed of inorganic nitrides (especially oxygen-free inorganic nitrides, specifically SnN or ZnN) is formed on the light-absorbing layer, or an electron transport precursor layer composed of inorganic sulfides (especially oxygen-free inorganic sulfides, specifically SnS, SnS2, or ZnS) is formed on the light-absorbing layer. Therefore, because inorganic nitrides such as SnN or ZnN, or inorganic sulfides such as SnS, SnS2, or ZnS, do not contain oxygen, oxidation of the perovskite compounds constituting the light-absorbing layer can be prevented during the process of forming the electron transport precursor layer.

[0014] According to one embodiment of the present invention, a first electron transport layer comprising inorganic nitrides or inorganic sulfides can serve as a damage prevention film or barrier film for its underlying layer. Furthermore, a second electron transport layer comprising inorganic metal nitrides or inorganic metal sulfides can serve as a damage prevention film or barrier film for its underlying layer.

[0015] According to one embodiment of the present invention, a first electron transport layer composed of inorganic nitrides (especially oxygen-free inorganic nitrides, specifically SnN or ZnN) is formed on the light-absorbing layer; or, a first electron transport layer composed of inorganic sulfides (especially oxygen-free inorganic sulfides, specifically SnS, SnS2, or ZnS) is formed on the light-absorbing layer. Therefore, because the inorganic nitrides, such as SnN or ZnN, or the inorganic sulfides, such as SnS, SnS2, or ZnS, do not contain oxygen, oxidation of the perovskite compound constituting the light-absorbing layer provided below the first electron transport layer can be prevented.

[0016] According to one embodiment of the present invention, the thickness of the second electron transport layer is greater than the thickness of the first electron transport layer, thereby improving the conductivity characteristics. Simple Explanation of the Diagram

[0017] Figures 1A to 1D are process diagrams for manufacturing solar cells according to an embodiment of the present invention. Figures 2A to 2E are process diagrams for manufacturing solar cells according to another embodiment of the present invention. Figures 3A to 3G are process diagrams for manufacturing solar cells according to another embodiment of the present invention. Figures 4A to 4H are process diagrams for manufacturing solar cells according to another embodiment of the present invention. Figures 5A to 5D are process diagrams for manufacturing solar cells according to another embodiment of the present invention. Implementation

[0018] The advantages and features of the invention, as well as methods of carrying it, will be illustrated by the embodiments described below with reference to the accompanying drawings. However, the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. These embodiments are provided rather than intended to enable a thorough and complete understanding of the invention 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.

[0019] The shapes, dimensions, proportions, angles, and quantities disclosed in the drawings to describe embodiments of the invention are merely exemplary, and therefore the invention is not limited to the details shown. Similar reference numerals throughout the text represent similar elements. In the following description, detailed descriptions of related prior art will be omitted where it is determined that such descriptions would unnecessarily obscure the focus of the invention. When using the terms "comprising," "having," and "including" as described in this specification, another component may be added unless "only" is used. Unless otherwise stated, singular terms may include plural forms.

[0020] When interpreting a component, although the error is not described in detail, the component should be interpreted as containing such an error.

[0021] When describing positional relationships, for example, using terms such as "above," "above," "below," and "beside" to describe the positional relationship between two components, unless terms such as "directly" or "right in front" are used, one or more other components may be placed between these two components.

[0022] When describing temporal relationships, for example, using terms like "after," "following," "next," and "before" to describe the sequence of events, discontinuous situations may be included unless terms such as "immediately after" or "directly" are used.

[0023] It will be understood that while terms such as "first," "second," etc., may be used herein to describe various elements, these elements should not be limited to these terms. These terms are used only to distinguish elements. For example, without departing from the scope of the invention, a first element may be named a second element, and similarly, a second element may be named a first element.

[0024] The term "at least one" should be understood as including any and all combinations of one or more of the listed related elements. For example, "at least one of the first element, the second element and the third element" means a combination of two or more first elements, second elements and third elements, as well as all elements selected from the first element, the second element and the third element.

[0025] The features of various embodiments of the present invention may be coupled or combined with each other in part or in whole, and may interact with each other in various ways and be technically driven in a manner that will be fully understood by one of ordinary skill in the art. Embodiments of the present invention may be implemented independently of each other, or may be implemented in a commonly related manner.

[0026] The preferred embodiments of the present invention will now be described in detail with reference to the relevant drawings.

[0027] Figures 1A to 1D are process diagrams for manufacturing solar cells according to an embodiment of the present invention.

[0028] First, as shown in Figure 1A, a first electrode 20 is formed on a substrate 10, a hole transport layer 30 is formed on the first electrode 20, and a light absorption layer 40 is formed on the hole transport layer 30.

[0029] The substrate 10 may be made of materials known to those skilled in the art, such as glass or plastic.

[0030] The first electrode 20 may be made of a conductive oxide such as ITO, but is not limited thereto. The first electrode 20 may be formed by a deposition process such as atomic layer deposition (ALD).

[0031] The hole transport layer may contain substances known to those skilled in the art, such as 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-MeO-TAD), 2,2',7,7'-tetratetra(N,N-xylyl)aminospirodifluorene (Spiro-TTB), polyaniline, polyphenol, poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid. The material can contain various p-type organic materials such as sulfonate (PEDOT-PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and poly(3-hexylthiophene-2,5-diyl) (P3HT), or various p-type metal oxides such as Ni oxide, Mo oxide, V oxide, W oxide, or Cu oxide, as well as various p-type organic or inorganic materials known to those skilled in the art. The hole transport layer 30 can be formed by deposition processes such as CVD (chemical vapor deposition) or ALD (atomic layer deposition).

[0032] The light-absorbing layer 40 is made of perovskite compound.

[0033] Perovskite compounds can be obtained by reacting at least one compound selected from amino compounds and amidine compounds, organometallic compounds containing divalent cations and at least one hydrogen halide to deposit ABX 3 compounds via chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0034] In ABX 3, A can be composed of a monovalent organic cation of an amino compound, a monovalent organic cation of an amidine compound, or a monovalent organic cation of both an amino compound and an amidine compound. A can have a structure in which a monovalent organic cation of an amino compound is contained in proportion x and a monovalent organic cation of an amidine compound is contained in proportion y. In this case, each of x and y is greater than 0, and x + y = 1.

[0035] In ABX 3, B is composed of divalent cations of organometallic compounds.

[0036] In ABX 3, X is composed of one or more halogen elements.

[0037] Amine compounds can be selected from the group consisting of methylamine, ethylamine, and phenethylamine.

[0038] Amidin compounds can be composed of formamidine.

[0039] Organometallic compounds containing divalent cations can include metals selected from the group consisting of lead (Pb), tin (Sn), germanium (Ge), antimony (Sb), bismuth (Bi), and barium (Ba).

[0040] In detail, organometallic compounds containing divalent cations can include compounds represented by the following chemical formula 1:

[0041] Chemical Formula 1

[0042]

[0043] In chemical formula 1, R1 to R12 are each independently composed of hydrogen or alkyl groups, and X is selected from the group consisting of Pb, Sn, Ge, Sb, Bi and Ba.

[0044] Alternatively, organometallic compounds containing divalent cations can be selected from the group consisting of Pb(CH3)4, Pb(C2H5)4, Pb(SCN), (C2H5)3PbOCH2C(CH3)3, Pb(C11H19O2)2, Pb((CH3)3C-COCHCO-C(CH3)3)2, Pb((C6H5)2PCH2P(C6H5)2)2, Pb(N(CH3)2C(CH3)2OH)2, and C12H28N2O2Pb.

[0045] The light absorption rate, optical band gap, carrier mobility, and material stability of the final perovskite compound can be adjusted according to the type of organometallic compound containing divalent positive ions.

[0046] Hydrogen halides can be selected from the group consisting of HI, HBr, HF, and HCl. The optical band gap of the final perovskite compound can be adjusted according to the type of hydrogen halide.

[0047] Amine compounds, amidine compounds, organometallic compounds containing divalent cations, and hydrogen halides are materials that evaporate in a temperature range between room temperature and 200 degrees Celsius, and preferably in a temperature range between 50 degrees Celsius and 150 degrees Celsius. Therefore, in the process of manufacturing the compound ABX 3, chemical vapor deposition (CVD) or atomic layer deposition (ALD) processes can be performed at temperatures below 200 degrees Celsius, preferably below 150 degrees Celsius, thus preventing the decomposition of organic materials in the final ABX 3 compound during the CVD or ALD process. Plasma can be applied during the CVD or ALD process.

[0048] According to another embodiment of the present invention, a perovskite compound can be obtained by chemical vapor deposition (CVD) or atomic layer deposition (ALD) by reacting at least one compound selected from amino compounds and amidine compounds, at least one alkali metal-based compound, an organometallic compound containing a divalent positive ion and at least one hydrogen halide to deposit a CABX 3 compound.

[0049] In CABX 3, A can be composed of a monovalent organic cation of an amino compound, a monovalent organic cation of an amidine compound, or a monovalent organic cation of an amino compound and a monovalent organic cation of an amidine compound.

[0050] In CABX 3, C can consist of at least one alkali metal-based compound.

[0051] CA can have a structure in which a monovalent organic cation of an amino group is contained in proportion x, a monovalent organic cation of an amidine group is contained in proportion y, and a monovalent cation of an alkali metal is contained in proportion z. In this case, each of x, y, and z is greater than 0, and x + y + z = 1.

[0052] In CABX 3, B consists of divalent positive ions, and X consists of one or more halogen elements.

[0053] Amine compounds, amidine compounds, organometallic compounds containing divalent cations, and hydrogen halides are described as above, and therefore their repeated descriptions will be omitted.

[0054] Alkali metal-based compounds may include compounds represented by the following chemical formula 2:

[0055] Chemical formula 2

[0056]

[0057] In chemical formula 2, R1 to R6 are each independently composed of hydrogen or alkyl groups, and Y is an alkali metal.

[0058] As described above, according to another embodiment of the present invention, at least one alkali metal-based compound may be added to the reactants, and thus the susceptibility of monovalent organic cations to water, heat and plasma can be compensated.

[0059] Next, as shown in Figure 1B, an electron transport precursor layer 50a is formed on the light absorption layer 40.

[0060] The electron transport precursor layer 50a can be formed from inorganic nitrides, particularly oxygen-free inorganic nitrides. Specifically, the electron transport precursor layer 50a can be formed from SnN or ZnN.

[0061] The electron transport precursor layer 50a can be formed from inorganic sulfides, particularly oxygen-free inorganic sulfides. Specifically, the electron transport precursor layer 50a can be formed from SnS, SnS₂, or ZnS.

[0062] Inorganic nitrides such as SnN or ZnN can be formed by deposition processes such as CVD or ALD. Because inorganic nitrides such as SnN or ZnN do not contain oxygen, oxidation of the perovskite compounds constituting the light-absorbing layer 40 can be prevented during the process of forming the electron transport precursor layer 50a.

[0063] Inorganic sulfides such as SnS, SnS2, or ZnS can be formed by deposition processes such as CVD or ALD. Because inorganic sulfides such as SnS, SnS2, or ZnS do not contain oxygen, oxidation of the perovskite compounds constituting the light-absorbing layer 40 can be prevented during the process of forming the electron transport precursor layer 50a.

[0064] Next, as shown in Figure 1C, oxygen plasma treatment is performed on the electron transport precursor layer 50a.

[0065] Then, oxygen can be injected into an inorganic metal nitride, such as SnN or ZnN, and the electron transport precursor layer 50a can be transformed into an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52, and a third electron transport layer 53.

[0066] Alternatively, oxygen can be injected into an inorganic metal sulfide such as SnS, SnS2, or ZnS, and the electron transport precursor layer 50a can be transformed into an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52, and a third electron transport layer 53.

[0067] Because no oxygen is introduced, the first electron transport layer 51 is a layer that contacts the light absorption layer 40 and is made of the same material as the inorganic metal nitride or inorganic metal sulfide that constitutes the electron transport precursor layer 50a. Therefore, the first electron transport layer 51 can be composed of an oxygen-free inorganic metal nitride (specifically SnN or ZnN) or an oxygen-free inorganic metal sulfide (specifically SnS, SnS2, or ZnS).

[0068] Because inorganic nitrides such as SnN or ZnN and inorganic sulfides such as SnS, SnS2, or ZnS do not contain oxygen, oxidation of the perovskite compounds constituting the light-absorbing layer provided beneath the first electron transport layer 51 can be prevented. Therefore, the first electron transport layer 51 containing inorganic nitrides or inorganic sulfides can act as a damage prevention film or barrier film for its underlying layer.

[0069] The second electron transport layer 52 is a layer formed on and in contact with the first electron transport layer 51, and oxygen is partially sprayed into the inorganic metal nitride or inorganic metal sulfide constituting the electron transport precursor layer 50a. Therefore, the second electron transport layer 52 can be made of inorganic metal nitride oxides (specifically SnON or ZnON) or inorganic metal sulfide oxides (specifically SnOS or ZnOS). The second electron transport layer 52 containing inorganic metal nitride oxides or inorganic metal sulfide oxides can act as a damage prevention film or barrier film under its underlying layer.

[0070] The third electron transport layer 53 is a layer formed on and in contact with the second electron transport layer 52. Oxygen is injected into the inorganic metal nitride constituting the electron transport precursor layer 50a to replace nitrogen with oxygen, or oxygen is injected into the inorganic metal sulfide constituting the electron transport precursor layer 50a to replace sulfur with oxygen. Therefore, the third electron transport layer 53 can be formed of an inorganic metal oxide (specifically SnO or ZnO).

[0071] Because the first electron transport layer 51 is composed of an oxygen-free inorganic metal nitride or inorganic metal sulfide (specifically SnN, ZnN, SnS, SnS2, or ZnS), oxidation of the perovskite compound constituting the light-absorbing layer 40 provided thereunder can be prevented, but its conductivity is not good.

[0072] On the other hand, compared to the first electron transport layer 51, the second electron transport layer 52 is made of inorganic metal nitride or inorganic metal sulfur oxide (specifically SnON, ZnON, SnOS, or ZnOS), so it has excellent conductivity. Therefore, in order to improve conductivity, it is desirable that the thickness t2 of the second electron transport layer 52 is thicker than the thickness t1 of the first electron transport layer 51.

[0073] In some cases, the second electron transport layer 52 may not be formed in process 1C. Specifically, by performing oxygen plasma treatment on the electron transport precursor layer 50a, the second electron transport layer 52 may not be formed on the same first electron transport layer 51 as the electron transport precursor layer 50a, but the third electron transport layer 53 may be formed directly on the first electron transport layer 51.

[0074] For example, a third electron transport layer 53 made of SnO or ZnO can be directly formed on top of a first electron transport layer 51 containing an inorganic metal nitride such as SnN or ZnN, or a third electron transport layer 53 made of SnO or ZnO can be directly formed on top of a first electron transport layer 51 containing an inorganic metal sulfide such as SnS, SnS2, or ZnS. In this case, the thickness of the third electron transport layer 53 will be thicker than the thickness of the first electron transport layer 51.

[0075] Next, as shown in Figure 1D, a transparent conductive layer 60 is formed on the electron transport layer 50, and a second electrode 70 is formed on the transparent conductive layer 60.

[0076] The transparent conductive layer 60 may contain a material with electron transport properties. The transparent conductive layer 60 may contain ITO or IZO, but is not limited to these. The transparent conductive layer 60 may be formed by a deposition process such as ALD.

[0077] The second electrode 70 can be made of a metallic material such as Ag. The second electrode 70 can be patterned into a predetermined shape so that sunlight can enter the battery.

[0078] Figures 2A to 2E are process diagrams for manufacturing solar cells according to another embodiment of the present invention.

[0079] First, as shown in Figure 2A, a first electrode 20 is formed on the substrate 10, a hole transport layer 30 is formed on the first electrode 20, and a light absorption layer 40 is formed on the hole transport layer 30.

[0080] The specific configuration of the substrate 10, the first electrode 20, the hole transport layer 30 and the light absorption layer 40 is the same as that of the previous embodiment, and therefore repeated explanations will be omitted.

[0081] Next, as shown in Figure 2B, an electron transport precursor layer 50a is formed on the light absorption layer 40.

[0082] The specific configuration of the substrate 10 and the electron transport precursor layer 50a is the same as that of the previous embodiment, and therefore repeated explanations will be omitted.

[0083] Next, as shown in Figure 2C, oxygen plasma treatment is performed on the electron transport precursor layer 50a.

[0084] Then, oxygen can be injected into an inorganic metal nitride, such as SnN or ZnN, and the electron transport precursor layer 50a can be transformed into a first electron transport layer 51 and a second electron transport layer 52.

[0085] Alternatively, oxygen can be injected into an inorganic metal sulfide such as SnS, SnS2, or ZnS, and the electron transport precursor layer 50a can be transformed into a first electron transport layer 51 and a second electron transport layer 52.

[0086] Because no oxygen is introduced, the first electron transport layer 51 is a layer that contacts the light absorption layer 40 and is made of the same material as the inorganic metal nitride or inorganic metal sulfide that constitutes the electron transport precursor layer 50a. Therefore, the first electron transport layer 51 can be composed of an oxygen-free inorganic metal nitride (specifically SnN or ZnN) or an oxygen-free inorganic metal sulfide (specifically SnS, SnS2, or ZnS).

[0087] The second electron transport layer 52 is a layer formed on the first electron transport layer 51, in which oxygen is partially ejected into the inorganic metal nitride or inorganic metal sulfide constituting the electron transport precursor layer 50a. Therefore, the second electron transport layer 52 can be made of inorganic metal nitride oxides (specifically SnON or ZnON) or inorganic metal sulfide oxides (specifically SnOS or ZnOS).

[0088] As in the above embodiment, it is preferable that the thickness t2 of the second electron transport layer 52 is thicker than the thickness t1 of the first electron transport layer 51.

[0089] In the aforementioned process 1C, a third electron transport layer 53 is additionally formed on the second electron transport layer 52 by oxygen plasma treatment on the electron transport precursor layer 50a. However, depending on the process conditions, even if oxygen is sprayed into the inorganic metal nitride or inorganic metal sulfide constituting the electron transport precursor layer 50a, nitrogen or sulfur may not be replaced by oxygen, so the third electron transport layer 53 may not be formed.

[0090] Next, as shown in FIG2D, a third electron transport layer 53 is formed on the second electron transport layer 52 to form an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52 and a third electron transport layer 53.

[0091] The third electron transport layer 53 can be formed from an inorganic metal oxide (specifically SnO or ZnO). The third electron transport layer 53 can be formed by a deposition process such as ALD.

[0092] At this point, it is desirable that the thickness t3 of the third electron transport layer 53 is greater than the thickness t1 of the first electron transport layer 51 to improve conductivity. Furthermore, the thickness t3 of the third electron transport layer 53 can be greater than the thickness t2 of the second electron transport layer 52.

[0093] In some cases, by omitting the aforementioned process 2C and performing process 2D after the aforementioned process 2B, a third electron transport layer 53 made of inorganic metal oxide (specifically SnO or ZnO) can be formed on the upper surface of the first electron transport layer 51 made of electron transport precursor layer 50a.

[0094] Next, as shown in Figure 2D, a transparent conductive layer 60 is formed on the electron transport layer 50, and a second electrode 70 is formed on the transparent conductive layer 60.

[0095] The specific configuration of the transparent conductive layer 60 and the second electrode 70 is the same as that of the previous embodiment, and therefore repeated explanations will be omitted.

[0096] In the above embodiment, the hole transport layer 30 is formed on the lower surface of the light absorption layer 40, and the electron transport layer 50 is formed on the upper surface of the light absorption layer 40, but it is not necessarily limited to this.

[0097] The hole transport layer 30 can be formed on the upper surface of the light absorption layer 40, and the electron transport layer 50 can be formed on the lower surface of the light absorption layer 40. This principle also applies to the following embodiments.

[0098] Figures 3A to 3G are process diagrams for manufacturing solar cells according to another embodiment of the present invention, and relate to perovskite solar cells and tandem solar cells of crystalline solar cells.

[0099] First, as shown in Figure 3A, a crystalline solar cell 100 is manufactured.

[0100] Crystalline solar cells 100 are manufactured by etching one and another surface of a semiconductor substrate 110, such as a wafer, to form a textured structure, doping a specific dopant on one surface of the semiconductor substrate 110 to form a first semiconductor layer 120, and doping a specific dopant on the other surface of the semiconductor substrate 110 to form a second semiconductor layer 130.

[0101] Because one surface and the other surface of the semiconductor substrate 110 are formed with an uneven structure, the first semiconductor layer 120 and the second semiconductor layer 130 will be formed with the shape of the corresponding uneven structure.

[0102] On the other hand, the drawings illustrate that one surface and the other surface of the semiconductor substrate 110 are formed with an uneven structure, but this is not necessarily a limitation. One surface of the semiconductor substrate 110 may be formed with an uneven structure, and the other surface may be formed with a flat structure. Alternatively, the other surface of the semiconductor substrate 110 may be formed with an uneven structure, and the one surface may be formed with a flat structure. In some cases, both the one surface and the other surface of the semiconductor substrate 110 may be formed with a flat structure.

[0103] The semiconductor substrate 110 can be formed from a P-type or N-type wafer. The first semiconductor layer 120 can be doped with a dopant having a different polarity than the dopant of the semiconductor substrate 110, and the second semiconductor layer 130 can be doped with a dopant having the same polarity as the dopant of the semiconductor substrate 110. For example, the semiconductor substrate 110 can be made from a P-type wafer, the first semiconductor layer 120 can be doped with an N-type dopant, and the second semiconductor layer 130 can be doped with a P-type dopant to form a P+ layer.

[0104] Next, as shown in Figure 3B, a buffer layer 200 is formed on the crystalline solar cell 100.

[0105] The buffer layer 200 is formed on the first semiconductor layer 120. Because the first semiconductor layer 120 is formed with an uneven structure, the buffer layer 200 is formed with a shape corresponding to the uneven structure.

[0106] A buffer layer 200 is provided between the crystalline solar cell 100 and the perovskite solar cell 300 described below, and thus the solar cell according to an embodiment of the present invention has a tandem solar cell structure based on a tunnel junction.

[0107] Preferably, the buffer layer 200 contains a material for allowing light with long wavelengths to pass through the perovskite solar cell 300 and be incident on the crystalline solar cell 100 without loss. For example, the buffer layer 200 may be formed of a transparent conductive oxide, a carbonaceous conductive material, a metallic material, or a conductive polymer, and in some cases, the material may be doped with n-type or p-type dopants.

[0108] Next, as shown in Figure 3C, a hole transport layer 30 is formed on the buffer layer 200, and a light absorption layer 40 is formed on the hole transport layer 30.

[0109] The specific configurations of the hole transport layer 30 and the light absorption layer 40 are the same as those in the aforementioned embodiments, and therefore repeated explanations will be omitted.

[0110] Next, as shown in Figure 3D, an electron transport precursor layer 50a is formed on the light absorption layer 40.

[0111] The specific configuration of the electron transport precursor layer 50a is the same as that of the aforementioned embodiment, and therefore repeated explanations will be omitted.

[0112] Next, as shown in Figure 3E, oxygen plasma treatment is performed on the electron transport precursor layer 50a.

[0113] Then, oxygen is injected into inorganic metal nitrides such as SnN or ZnN, or inorganic metal sulfides such as SnS, SnS2, or ZnS, so that the electron transport precursor layer 50a can be transformed into an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52, and a third electron transport layer 53.

[0114] The specific configuration of the electron transport layer 50, which includes the first electron transport layer 51, the second electron transport layer 52 and the third electron transport layer 53, is the same as that in FIG1C, and therefore repeated descriptions will be omitted.

[0115] Next, as shown in Figure 3F, a transparent conductive layer 60 is formed on the electron transport layer 50.

[0116] The specific configuration of the transparent conductive layer 60 is the same as that of the previous embodiment, and therefore repeated explanations will be omitted.

[0117] Next, as shown in Figure 3G, the first electrode 20 is formed on the bottom surface of the crystalline solar cell 100, and the second electrode 70 is formed on the top surface of the transparent conductive layer 60.

[0118] Because the second electrode 70 is formed on the incident surface for sunlight, the second electrode 70 is patterned into a predetermined shape. The first electrode 20 can also be used to allow reflected sunlight to enter the solar cell by forming a pattern of a predetermined shape, but this is not a limitation.

[0119] The specific configurations of the first electrode 20 and the second electrode 70 are the same as those in the aforementioned embodiments, and therefore repeated explanations will be omitted.

[0120] The first electrode 20 and the second electrode 70 can be formed using various patterning methods and various conductive materials known in the art.

[0121] Although not shown in detail, a passivation layer may be formed on the second electrode 70. In this case, a portion of the passivation layer may be etched to expose the second electrode 70.

[0122] Figures 4A to 4H are process diagrams for manufacturing solar cells according to another embodiment of the present invention, and relate to perovskite solar cells and tandem solar cells of crystalline solar cells.

[0123] First, as shown in Figure 4A, a crystalline solar cell 100 is manufactured.

[0124] Crystalline solar cells 100 are manufactured by etching one and another surface of a semiconductor substrate 110, such as a wafer, to form a textured structure, doping a specific dopant on one surface of the semiconductor substrate 110 to form a first semiconductor layer 120, and doping a specific dopant on the other surface of the semiconductor substrate 110 to form a second semiconductor layer 130.

[0125] Since the specific configuration of the semiconductor substrate 110, the first semiconductor layer 120 and the second semiconductor layer 130 is the same as that in FIG3A, the repeated explanation will be omitted.

[0126] Next, as shown in Figure 4B, a buffer layer 200 is formed on the crystalline solar cell 100.

[0127] Since the specific configuration of buffer layer 200 is the same as that in Figure 3B above, its repeated description will be omitted.

[0128] Next, as shown in Figure 4C, a hole transport layer 30 is formed on the buffer layer 200, and a light absorption layer 40 is formed on the hole transport layer 30.

[0129] Since the specific configurations of the hole transport layer 30 and the light absorption layer 40 are the same as those in Figure 3C, their repeated descriptions will be omitted.

[0130] Next, as shown in Figure 4D, an electron transport precursor layer 50a is formed on the light absorption layer 40.

[0131] Since the specific configuration of the electron transport precursor layer 50a is the same as that in Figure 3D above, its repeated description will be omitted.

[0132] Next, as shown in Figure 4E, oxygen plasma treatment is performed on the electron transport precursor layer 50a.

[0133] Then, oxygen is injected into inorganic metal nitrides such as SnN or ZnN, or inorganic metal sulfides such as SnS, SnS2, or ZnS, so that the electron transport precursor layer 50a can be transformed into a first electron transport layer 51 and a second electron transport layer 52.

[0134] Since the specific configurations of the first electron transport layer 51 and the second electron transport layer 52 are the same as those in Figure 2C above, their repeated descriptions will be omitted.

[0135] Next, as shown in FIG4F, a third electron transport layer 53 is formed on the second electron transport layer 52 to form an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52 and a third electron transport layer 53.

[0136] Since the specific configuration of the third electron transport layer 53 is the same as that in Figure 2D above, its repeated description will be omitted.

[0137] As described in the above embodiment, by omitting process 4E and performing process 4F after process 4D, an electron transport layer 50 including a first electron transport layer 51 and a third electron transport layer 53 provided on the upper surface of the first electron transport layer 51 can be formed.

[0138] Next, as shown in Figure 4G, a transparent conductive layer 60 is formed on the electron transport layer 50.

[0139] Since the specific configuration of the transparent conductive layer 60 is the same as that in Figure 3F above, its repeated description will be omitted.

[0140] Next, as shown in Figure 4H, the first electrode 20 is formed on the bottom surface of the crystalline solar cell 100, and the second electrode 70 is formed on the top surface of the transparent conductive layer 60.

[0141] Since the detailed configuration of the first electrode 20 and the second electrode 70 is the same as that in Figure 3G above, the repeated description will be omitted.

[0142] Although not shown in detail, a passivation layer may be formed on the second electrode 70. In this case, a portion of the passivation layer may be etched to expose the second electrode 70.

[0143] Figures 5A to 5D are process diagrams for manufacturing a solar cell according to another embodiment of the present invention. The difference between Figures 5A to 5D and Figures 1A to 1D is that Figures 5A to 5D additionally include the process of forming a passivation layer 80 and an organic material layer 90.

[0144] First, as shown in Figure 5A, a first electrode 20 is formed on the substrate 10, a hole transport layer 30 is formed on the first electrode 20, a light absorption layer 40 is formed on the hole transport layer 30, a passivation layer 80 is formed on the light absorption layer 40, and an organic material layer 90 is formed on the passivation layer 80.

[0145] The specific configuration of the substrate 10, the first electrode 20, the hole transport layer 30 and the light absorption layer 40 is the same as that of the previous embodiment, and therefore repeated explanations will be omitted.

[0146] The passivation layer 80 can be formed from an oxygen-free inorganic insulating layer, such as silicon nitride.

[0147] The organic material layer 90 can be formed from fullerenes or fullerene derivatives. For example, the organic material layer 90 can be formed from C60 or phenyl-C61-butyric acid methyl ester (PCBM).

[0148] Next, as shown in Figure 5B, an electron transport precursor layer 50a is formed on the light absorption layer 40.

[0149] Since the specific configuration of the electron transport precursor layer 50a is the same as that in Figure 1B above, its repeated description will be omitted.

[0150] Next, as shown in Figure 5C, oxygen plasma treatment is performed on the electron transport precursor layer 50a.

[0151] Then, oxygen can be injected into an inorganic metal nitride, such as SnN or ZnN, and the electron transport precursor layer 50a can be transformed into an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52, and a third electron transport layer 53.

[0152] Alternatively, oxygen can be injected into an inorganic metal sulfide such as SnS, SnS2, or ZnS, and the electron transport precursor layer 50a can be transformed into an electron transport layer 50 comprising a first electron transport layer 51, a second electron transport layer 52, and a third electron transport layer 53.

[0153] The specific configurations of the first electron transport layer 51, the second electron transport layer 52, and the third electron transport layer 53 are the same as those in Figure 1C, and therefore their repeated descriptions will be omitted.

[0154] In this case, the first electron transport layer 51 and the second electron transport layer 52 can act as a damage prevention film or barrier film to prevent damage to the passivation layer 80 and the organic material layer 90.

[0155] Next, as shown in FIG5D, a transparent conductive layer 60 is formed on the electron transport layer 50, and a second electrode 70 is formed on the transparent conductive layer 60.

[0156] Since the specific configuration of the transparent conductive layer 60 and the second electrode 70 is the same as that in Figure 1D above, the repeated description will be omitted.

[0157] Although not specifically illustrated, the embodiments shown in Figures 2A to 2E may additionally include processes for forming a passivation layer 80 and an organic material layer 90. That is, in the aforementioned process of Figure 2A, the passivation layer 80 and the organic material layer 90 may be formed sequentially on the light-absorbing layer 40, and then in the process of Figure 2B, the electron transport precursor layer 50a may be formed on the organic material layer 90.

[0158] Furthermore, the process of forming the passivation layer 80 and the organic material layer 90 can be additionally included in the embodiments according to Figures 3A to 3G above. That is, in the process of Figure 3C, the passivation layer 80 and the organic material layer 90 can be sequentially formed on the light-absorbing layer 40, and then in the process of Figure 3D, the electron transport precursor layer 50a can be formed on the organic material layer 90.

[0159] Furthermore, the process of forming the passivation layer 80 and the organic material layer 90 can be additionally included in the embodiments according to Figures 4A to 4H above. That is, in the process of Figure 4C, the passivation layer 80 and the organic material layer 90 can be sequentially formed on the light-absorbing layer 40, and then in the process of Figure 4D, the electron transport precursor layer 50a can be formed on the organic material layer 90.

[0160] 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 these embodiments and can be modified in various ways without departing from the technical spirit of the present invention. Therefore, it should be understood that in each aspect, the above embodiments are merely exemplary and not restrictive. It should be explained that the scope of the present invention is defined by the following claims rather than by the implementation methods, and the scope and meaning of the claims, as well as all variations and modifications derived from concepts equivalent to the claims, are included within the scope of the present invention.

[0161] 10:Substrate 100: Crystalline Solar Cell 110: Semiconductor substrate 120: First semiconductor layer 130: Second semiconductor layer 20: First electrode 200: Buffer layer 30: Hole transport layer 40: Light Absorption Layer 50: Electron transport layer 50a: Electron transport precursor layer 51: First electron transport layer 52: Second electron transport layer 53: Third electron transport layer 60: Transparent conductive layer 70: Second electrode 80: Passivation layer 90: Organic material layer t1: Thickness t2: thickness t3: Thickness

Claims

1. A solar cell comprising: a light-absorbing layer comprising a perovskite compound; and an electron transport layer provided on a first surface of the light-absorbing layer, wherein the electron transport layer comprises a first electron transport layer provided on the first surface of the light-absorbing layer and a second electron transport layer provided on the first electron transport layer, and wherein the first electron transport layer comprises an inorganic metal nitride and the second electron transport layer comprises an inorganic metal oxynitride, or the first electron transport layer comprises an inorganic metal sulfide and the second electron transport layer comprises an inorganic metal oxysulfide.

2. The solar cell as claimed in claim 1, wherein the first electron transport layer comprises SnN and the second electron transport layer comprises SnON, or, the first electron transport layer comprises ZnN and the second electron transport layer comprises ZnON, or, the first electron transport layer comprises SnS or SnS2 and the second electron transport layer comprises SnOS, or the first electron transport layer comprises ZnS and the second electron transport layer comprises ZnOS.

3. The solar cell as claimed in claim 1 further includes a passivation layer located between the light-absorbing layer and the electron transport layer.

4. The solar cell as described in claim 3 further comprises an organic material layer located between the passivation layer and the electron transport layer.

5. The solar cell as claimed in claim 1, wherein the thickness of the second electron transport layer is greater than the thickness of the first electron transport layer.

6. The solar cell as claimed in claim 1 further includes a third electron transport layer located on the second electron transport layer, wherein the third electron transport layer comprises an inorganic metal oxide.

7. The solar cell as claimed in claim 6, wherein the third electron transport layer comprises SnO or ZnO.

8. A solar cell comprising: a light-absorbing layer comprising a perovskite compound; and an electron transport layer provided on a first surface of the light-absorbing layer, wherein the electron transport layer comprises a first electron transport layer provided on the first surface of the light-absorbing layer and a third electron transport layer provided on the first electron transport layer, and wherein the first electron transport layer comprises an inorganic metal nitride or an inorganic metal sulfide, and the third electron transport layer comprises an inorganic metal oxide.

9. The solar cell of claim 8, wherein the first electron transport layer comprises SnN, SnS or SnS2 and the third electron transport layer comprises SnO, or the first electron transport layer comprises ZnN or ZnS and the third electron transport layer comprises ZnO.

10. The solar cell as claimed in claim 8, wherein the thickness of the third electron transport layer is greater than the thickness of the first electron transport layer.

11. The solar cell as claimed in claim 8 further comprises a passivation layer located between the light-absorbing layer and the electron transport layer, and an organic material layer located between the passivation layer and the electron transport layer.

12. The solar cell of claim 8 further comprises a transparent conductive layer located on the electron transport layer, wherein the transparent conductive layer comprises a material having electron transport characteristics.

13. The solar cell as claimed in claim 1 or 8 further comprises a buffer layer located on a second surface of the light-absorbing layer and a crystalline solar cell located on the buffer layer.

14. A method of manufacturing a solar cell, comprising: forming a light-absorbing layer comprising a perovskite compound; and forming an electron transport layer on a first surface of the light-absorbing layer, wherein forming the electron transport layer comprises: forming an electron transport precursor layer comprising an inorganic metal nitride or an inorganic metal sulfide, and performing an oxygen plasma treatment on the electron transport precursor layer to form a first electron transport layer comprising an inorganic metal nitride or an inorganic metal sulfide and a second electron transport layer comprising an inorganic metal oxynitride or an inorganic metal sulfide.

15. The method of manufacturing a solar cell as claimed in claim 14, wherein the electron transport precursor layer and the first electron transport layer comprise SnN and the second electron transport layer comprises SnON, or, the electron transport precursor layer and the first electron transport layer comprise ZnN and the second electron transport layer comprises ZnON, or, the electron transport precursor layer and the first electron transport layer comprise SnS or SnS2 and the second electron transport layer comprises SnOS, or the electron transport precursor layer and the first electron transport layer comprise ZnS and the second electron transport layer comprises ZnOS.

16. The method of manufacturing a solar cell as described in claim 14 further comprises forming a third electron transport layer comprising an inorganic metal oxide on the second electron transport layer, wherein the third electron transport layer comprises SnO or ZnO.

17. The method of manufacturing a solar cell as described in claim 14 further comprises forming a passivation layer between the light-absorbing layer and the electron transport layer, and forming an organic material layer between the passivation layer and the electron transport layer.

18. A method of manufacturing a solar cell, comprising: forming a light-absorbing layer comprising a perovskite compound; and forming an electron transport layer on a first surface of the light-absorbing layer, wherein forming the electron transport layer comprises: forming an electron transport precursor layer comprising an inorganic metal nitride or an inorganic metal sulfide, and performing an oxygen plasma treatment on the electron transport precursor layer to form a first electron transport layer comprising an inorganic metal nitride or an inorganic metal sulfide and a third electron transport layer comprising an inorganic metal oxide.

19. The method of manufacturing a solar cell as claimed in claim 18, wherein the first electron transport layer comprises SnN, SnS or SnS2 and the third electron transport layer comprises SnO, or the first electron transport layer comprises ZnN or ZnS and the third electron transport layer comprises ZnO.

20. The method of manufacturing a solar cell as described in claim 18 further comprises forming a passivation layer between the light-absorbing layer and the electron transport layer, and forming an organic material layer between the passivation layer and the electron transport layer.

21. The method of manufacturing a solar cell as described in claim 18 further comprises forming a transparent conductive layer on the electron transport layer, wherein the transparent conductive layer comprises a material having electron transport characteristics.

22. The method of manufacturing a solar cell as described in claim 14 or 18 further includes forming a crystalline solar cell and forming a buffer layer on the crystalline solar cell before forming the light-absorbing layer, wherein the light-absorbing layer is provided on the buffer layer.

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