Perovskite solar cell and tandem solar cell including the same

Abstract

One embodiment of the present invention discloses a perovskite solar cell comprising a substrate, a first electrode disposed on the substrate, a second electrode disposed opposite to the first electrode, a photoactive layer containing a perovskite-based material disposed between the first electrode and the second electrode, and an electron transport layer disposed between the photoactive layer and the second electrode and comprising an organic material and a metal complexing agent.

Description

Technology Field

[0001] The present invention relates to a perovskite solar cell and a tandem solar cell including the same. Background Technology

[0002] In order to address the depletion of fossil fuels and the global environmental problems caused by their use, research on renewable and clean alternative energy sources such as solar, wind, and hydroelectric power is actively underway.

[0003] Among these, interest in solar cells, which convert solar energy into electrical energy, is increasing significantly. Here, a solar cell refers to a battery that generates current and voltage by utilizing the photovoltaic effect, which absorbs light energy from sunlight to generate electrons and holes.

[0004] Meanwhile, perovskite solar cells are considered a key next-generation technology, and these perovskite solar cells include a photoactive layer containing a perovskite compound and may additionally include one or more electron transport layers, such as an electron transport layer.

[0005] Among currently mass-producible technologies, fullerene thin films formed on perovskite photoactive layers are attracting attention as electron transport layers. However, fullerene layers have several limitations due to the inherent properties of the material itself. The problem to be solved

[0006] The present invention provides a solar cell with improved performance and stability. means of solving the problem

[0007] One embodiment of the present invention discloses a perovskite solar cell comprising a substrate, a first electrode disposed on the substrate, a second electrode disposed opposite to the first electrode, a photoactive layer containing a perovskite-based material disposed between the first electrode and the second electrode, and an electron transport layer disposed between the photoactive layer and the second electrode and comprising an organic material and a metal complexing agent.

[0008] In the present embodiment, the electron transport layer comprises a first electron transport layer and a second electron transport layer, wherein the first electron transport layer comprises an organic material and a metal complexing agent, and the second electron transport layer may comprise a metal oxide.

[0009] In this embodiment, the thickness of the first electron transfer layer may be 5 nm to 30 nm.

[0010] In this embodiment, the organic material may include a fullerene-based material.

[0011] In the present embodiment, the metal complexing agent may include one or more selected from Quinolinolato (8-Hydroxyquinoline) Complexes, β-Diketonates (Metal Acetylacetonates, M(acac)), Salen and Salophen Complexes, Porphyrin and Phthalocyanine Complexes, Ir(III) Complexes, Pt(II) Complexes, Pd(II) Complexes, Zn(II) Complexes, Ruthenium(II) Polypyridyl Complexes, Phthalocyanine Complexes and / or Crown Ethers and Cryptands.

[0012] In the present embodiment, the Quinolinolato (8-Hydroxyquinoline) Complexes may include one or more selected from Liq (8-Quinolinolato Lithium), Alq (Aluminum tris(8-hydroxyquinoline)), Znq₂ (Zinc bis(8-hydroxyquinoline)), and Mgq₂ (Magnesium bis(8-hydroxyquinoline)).

[0013] In the present embodiment, the organic material and the metal complexing agent may include a ratio of the metal complexing agent to the organic material of 0.1 at.% to 50 at.%.

[0014] In this embodiment, a passivation layer disposed between the perovskite photoactive layer and the electron transport layer may be further included.

[0015] In the present embodiment, the passivation layer comprises a passivation material, and the metal complexing agent may be combined with the passivation material.

[0016] In the present embodiment, the passivation material may include one or more selected from LiF, KF, and CsF.

[0017] Another embodiment of the present invention discloses a tandem solar cell comprising a silicon layer, a recombination layer on the silicon layer, an electrode disposed opposite to the recombination layer, a photoactive layer containing a perovskite-based material disposed between the recombination layer and the electrode, and an electron transfer layer disposed between the electrode and the photoactive layer and comprising an organic material and a metal complex.

[0018] In the present embodiment, the electron transport layer comprises a first electron transport layer and a second electron transport layer, wherein the first electron transport layer comprises an organic material and a metal complexing agent, and the second electron transport layer may comprise a metal oxide.

[0019] In this embodiment, the thickness of the first electron transfer layer may be 5 nm to 30 nm.

[0020] In this embodiment, the organic material may include a fullerene-based material.

[0021] In the present embodiment, the metal complexing agent may include one or more selected from Quinolinolato (8-Hydroxyquinoline) Complexes, β-Diketonates (Metal Acetylacetonates, M(acac)), Salen and Salophen Complexes, Porphyrin and Phthalocyanine Complexes, Ir(III) Complexes, Pt(II) Complexes, Pd(II) Complexes, Zn(II) Complexes, Ruthenium(II) Polypyridyl Complexes, Phthalocyanine Complexes and / or Crown Ethers and Cryptands.

[0022] In the present embodiment, the Quinolinolato (8-Hydroxyquinoline) Complexes may include one or more selected from Liq (8-Quinolinolato Lithium), Alq (Aluminum tris(8-hydroxyquinoline)), Znq₂ (Zinc bis(8-hydroxyquinoline)), and Mgq₂ (Magnesium bis(8-hydroxyquinoline)).

[0023] In this embodiment, the organic material and the metal complexing agent may include a ratio of the metal complexing agent to the organic material of 0.1 at.% to 50 at.%.

[0024] In this embodiment, a passivation layer disposed between the perovskite photoactive layer and the electron transport layer may be further included.

[0025] In the present embodiment, the passivation layer comprises a passivation material, and the metal complexing agent may be combined with the passivation material.

[0026] In the present embodiment, the passivation layer may include one or more selected from LiF, KF, and CsF. Effects of the invention

[0027] In the solar cell according to the embodiments of the present invention, the power conversion efficiency and reliability of the device can be improved by including a fullerene and a metal complex in the electron transport layer. Brief explanation of the drawing

[0028] FIG. 1 is a cross-sectional view schematically illustrating an example of a perovskite solar cell according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating an example of a tandem solar cell including a perovskite solar cell according to one embodiment of the present invention. FIG. 3 is a cross-sectional view schematically illustrating another example of a tandem solar cell including a perovskite solar cell according to one embodiment of the present invention. Specific details for implementing the invention

[0029] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted.

[0031] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0032] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0033] In the following embodiments, terms such as "include" or "have" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0034] In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, so the present invention is not necessarily limited to what is illustrated.

[0035] In the following embodiments, the x-axis, y-axis, and z-axis are not limited to three axes in an orthogonal coordinate system and can be interpreted in a broader sense that includes them. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but they may also refer to different directions that are not orthogonal to each other.

[0036] Where an embodiment can be implemented differently, a specific process sequence may be performed differently from the order described. For example, two processes described consecutively may be performed substantially simultaneously or proceed in the reverse order of the description.

[0037] FIG. 1 is a cross-sectional view schematically illustrating an example of a perovskite solar cell according to one embodiment of the present invention.

[0038] Referring to FIG. 1, a perovskite solar cell (1) may include a substrate (10), a first electrode (20), a photoactive layer (40), an electron transport layer (60), and a second electrode (80).

[0039] Additionally, the perovskite solar cell (1) may include one or more additional layers as an optional embodiment, and, for example, may include a hole transport layer (30) between the first electrode (20) and the photoactive layer (40).

[0040] Additionally, a transparent electrode (70) may be included between the electron transport layer (60) and the second electrode (80).

[0041] Additionally, as an optional embodiment, a passivation layer (50) may be further included between the photoactive layer (40) and the electron transport layer (60).

[0042] Additionally, as an optional embodiment, one or more anti-reflective films on the transparent electrode (70) may be further included.

[0043] Meanwhile, the perovskite solar cell according to one embodiment of the present invention illustrated in FIG. 1 relates to a pin planar structure among the four structures of a general perovskite solar cell, namely, nip mesoscopic, nip planar, pin planar, and pin mesoscopic structures.

[0044] However, the structure of the perovskite solar cell illustrated in FIG. 1 is one embodiment and is not limited thereto, and the composition of the composite layer according to the embodiment of the present invention can be applied in the same way to perovskite solar cells modified with a different structure, a different stacking order, or a different configuration.

[0045] A substrate (10) may be placed on a bottom surface to form a perovskite solar cell (1) and may include any one selected from glass, for example, borosilicate glass or quartz glass, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), polypropylene (PP), triacetylcellulose (TAC), or polyethersulfone (PES), but is not limited thereto.

[0046] The first electrode (20) can be placed on the substrate (10) and can be formed of various conductive materials, for example, a conductive material having light transparency.

[0047] As a specific example, the first electrode (20) may include a transparent conductive oxide, a carbonaceous conductive material, and a metallic material. Examples of transparent conductive oxides may include ITO (Indium Tin Oxide), ICO (Indium Cerium Oxide), IWO (Indium Tungsten Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide), GITO (Gallium Indium Tin Oxide), GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum-doped Zinc Oxide), FTO (Fluorine Tin Oxide), ZnO, etc.

[0048] As the carbonaceous conductive material, for example, graphene or carbon nanotubes may be used, and as the metallic material, for example, metal (Ag) nanowires or metal thin films with a multilayer structure such as Au / Ag / Cu / Mg / Mo / Ti may be used.

[0049] In this specification, the term "transparent" refers to the ability to transmit light to a certain degree or more, and is not necessarily interpreted to mean complete transparency. The materials described above are not necessarily limited to the embodiments described above and can be formed from various materials, and their structure can also be varied, such as being single-layer or multi-layered.

[0050] The hole transport layer (30) may be a layer formed on the first electrode (20) to which holes formed in the perovskite photoactive layer (40) described later are transported. For example, the hole transport layer (30) may include one or more selected from tungsten oxide (WOx), molybdenum oxide (MoOx), vanadium oxide (V2O5), and nickel oxide (NiOx), and may also include at least one selected from the group consisting of monomolecular hole transport materials and polymeric hole transport materials, but is not limited thereto and any material used in the industry may be used.

[0051] Monomolecular hole transport materials may include, for example, spiro-MeOTAD [2,2',7,7'-tetrakis(N,Np-dimethoxy-phenylamino)-9,9'-spirobifluorene], and polymeric hole transport materials may include, for example, P3HT [poly(3-hexylthiophene)], PTAA (polytriarylamine), poly(3,4-ethylenedioxythiophene) or polystyrene sulfonate (PEDOT:PSS), but are not limited thereto.

[0052] Meanwhile, the hole transport layer (30) may further include a doping material. For example, the doping material may be a dopant selected from the group consisting of Li-based dopants, Co-based dopants, Cu-based dopants, Cs-based dopants, and combinations thereof, but is not limited thereto.

[0053] A photoactive layer (40) containing a perovskite-based material can be formed on a hole transport layer (30), and, for example, can perform the role of separating hole-electron pairs generated by receiving light energy from the sun into electrons or holes.

[0054] At this time, electrons formed in the perovskite photoactive layer (40) are transferred to the electron transport layer (60) described later, and holes formed in the perovskite photoactive layer (40) can be transferred to the hole transport layer (30).

[0055] For example, the perovskite photoactive layer (40) may include a perovskite-based material, and as a specific example, the perovskite-based material may have an organic-inorganic hybrid perovskite structure represented by the chemical formula ABX3 (wherein A may be a monovalent organic cation or metal cation, B may be a divalent metal cation, and X may be a halogen anion).

[0056] As a specific example, the perovskite photoactive layer (40) may include organic halide perovskites such as methyl ammonium iodide (MAI) and formamidinium iodide (FAI), or metal halide perovskites such as lead iodide (PbI2), bromine iodide (PbBr), and lead chloride (PbCl2), and may be a multilayer stacked structure including at least one of organic halide perovskites or metal halide perovskites. More specifically, the perovskite photoactive layer (40) may be CH3NH3PbI3, CH3NH3PbI x Cl 3-x , CH3NH3PbI x Br 3-x , CH3NH3PbCl x Br 3-x , HC(NH2)2PbI3, HC(NH2)2PbI x Cl 3-x , HC(NH2)2PbI x Br 3-x , HC(NH2)2PbCl x Br 3-x , (CH3NH3)(HC(NH2)2) 1-y PbI3, (CH3NH3)(HC(NH2)2) 1-y PbI x Cl 3-x, (CH3NH3)(HC(NH2)2) 1-y PbI x Br 3-x , or (CH3NH3)(HC(NH2)2) 1-y PbCl x Br 3-x It may include the back (0≤x, y≤1).

[0057] The electron transport layer (60) may be formed on the perovskite photoactive layer (40) and may include an electron transport material. For example, the electron transport material may include a metal oxide or an organic material, and when a hole-electron pair generated by receiving light energy from the sun is separated into an electron or a hole in the perovskite photoactive layer (40), the electron can be received and easily transferred to the second electrode (80) described later.

[0058] In the second part, the electron transport layer (60) according to an embodiment of the present invention may include a first electron transport layer (61) and a second electron transport layer (62).

[0059] The first electron transport layer (61) may be disposed adjacent to the perovskite photoactive layer (40) and may include an organic material, for example, the organic material may include a fullerene-based material. Additionally, the first electron transport layer (61) according to an embodiment of the present invention may further include a metal complexing agent. When the first electron transport layer (61) includes, for example, an organic material and a metal complexing agent, the first electron transport layer (61) can more easily receive electrons formed in the perovskite photoactive layer (40).

[0060] Additionally, the metal complex can be positioned to fill the empty spaces of the organic material, thereby improving the density of the first electron transport layer (61). For example, if the organic material includes a fullerene-based material, the organic material may have a spherical structure, and the metal complex can be positioned to fill the empty spaces of this spherical structure, thereby improving the density of the first electron transport layer (61).

[0061] As a specific example, the first electron transport layer (61) may include a fullerene-based material and a metal complex, wherein the metal complex may include, for example, one or more selected from Quinolinolato (8-Hydroxyquinoline) Complexes, β-Diketonates (Metal Acetylacetonates, M(acac)), Salen and Salophen Complexes, Porphyrin and Phthalocyanine Complexes, Ir(III) Complexes, Pt(II) Complexes, Pd(II) Complexes, Zn(II) Complexes, Ruthenium(II) Polypyridyl Complexes, Phthalocyanine Complexes and / or Crown Ethers and Cryptands.

[0062] As specific examples, Quinolinolato (8-Hydroxyquinoline) Complexes may include one or more selected from Liq (8-Quinolinolato Lithium), Alq (Aluminum tris(8-hydroxyquinoline)), Znq₂ (Zinc bis(8-hydroxyquinoline)), and Mgq₂ (Magnesium bis(8-hydroxyquinoline)); β-Diketonates may include one or more selected from Li(acac) (Lithium acetylacetonate), Al(acac)3 (Aluminum acetylacetonate), and Fe(acac)3 (Iron acetylacetonate); and Salen and Salophen Complexes may include one or more selected from Ni(Salen) (Nickel Salen Complex) and Co(Salen) (Cobalt Salen Complex).

[0063] In an optional embodiment, the first electron transport layer (61) may include fullerene and Liq (8-Quinolinolato Lithium).

[0064] Meanwhile, fullerenes are widely used as electron transport materials as excellent electron transport acceptors, but when fullerenes are used alone, they can be a factor that reduces the efficiency and stability of the device due to their molecular structure characteristics, such as higher LUMO levels and spherical structures compared to perovskite-based materials.

[0065] Specifically, in order for electrons formed in the perovskite photoactive layer (40) to move smoothly to the first electron transport layer (61), it must have a LUMO level similar to that of the perovskite photoactive layer (40). However, fullerene has a higher LUMO level than this, which can hinder the interlayer movement of electrons and become a factor that lowers the efficiency of the device.

[0066] In addition, due to the spherical structure of fullerenes, each carbon atom is completely bonded to three neighboring carbon atoms and therefore does not have unpaired electrons or unconnected bonds. While this bonding structure allows fullerene molecules to possess stability, it can be difficult for them to easily bond with other layers. Consequently, when external stress is applied, they become the most mechanically vulnerable parts, which can lead to mechanical stress or problems such as cracking and delamination during the manufacturing process.

[0067] To compensate for these problems, the first electron transport layer (61) according to an embodiment of the present invention may further include a metal complexing agent, and by further including the metal complexing agent, the energy level between the fullerene and the perovskite photoactive layer (40) can be matched, and the density of the thin film can be improved by filling the spherical fullerene structure, thereby improving the low adhesion of the thin film.

[0068] Meanwhile, metal complexes consist of a central metal ion coordinately bonded to an organic ligand, and due to the interaction between the metal core and the ligand, they possess electron transfer properties and can also have the property of binding to metal ions.

[0069] Due to the characteristics of this metal complex, the first electron transport layer (61) can achieve energy level optimization with the perovskite photoactive layer (40), and the adhesion is improved so that bonding with other layers is easy.

[0070] Meanwhile, the ratio of the metal complex to the fullerene in the first electron transport layer (61) may be 0.1 at.% to 50 at.%, and more preferably 0.1 at.% to 30 at.%. At this time, if the ratio of the metal complex to the fullerene is less than 0.1 at.%, it may be difficult to match the energy band alignment with the perovskite photoactive layer, and if the ratio of the metal complex to the fullerene is more than 50 at.%, the insulation properties may be strengthened and the electron transport capability may be reduced.

[0071] Meanwhile, although both fullerene and metal complexing agents have electron transfer characteristics, in the structure of the first electron transfer layer (61), fullerene can exhibit superior electron transfer characteristics compared to metal complexing agents, so when the ratio of metal complexing agents to fullerene is 0.1 at.% to 30 at.%, the first electron transfer layer (61) can exhibit optimal electron transfer characteristics.

[0073] Type C60[Atomic percent, at%] Liq[Atomic percent, at%] Voc[V] Jsc[mA / cm 2 ] FF[%] PEC[%] Comparative Example 1 100 0 1.725 18.14 69.63 21.79 Comparative Example 2 0 100 1.696 17.26 46.24 13.54 Example 1 99.5 0.5 1.774 18.59 71.02 23.43 Example 2 90 10 1.807 18.54 73.50 24.62 Example 3 70 30 1.811 18.56 73.72 24.77 Example 4 50 50 1.780 18.45 70.73 23.23 Example 5 30 70 1.737 17.22 65.48 19.58 Example 6 10 90 1.720 17.24 65.58 19.44

[0074] Table 1 shows the parameters of a solar cell device according to the atomic percentage ratio of fullerene and metal complex in the first electron transport layer. In this case, the solar cell device may be a tandem solar cell device including a perovskite solar cell. Referring to Table 1, it can be seen that the open-circuit voltage (Voc), charge factor (FF), and power conversion efficiency (PCE) of the solar cell device in Examples 1 to 4, which include both fullerene and metal complex, are all improved compared to Comparative Example 1 and Comparative Example 2, which include only fullerene and metal complex, respectively. In particular, it can be seen that Example 3 exhibits the best performance with an open-circuit voltage (Voc) of 1.811V, a charge factor (FF) of 73.72%, and a power conversion efficiency (PCE) of 24.77%.

[0075] Meanwhile, in the case of Examples 5 and 6, where the atomic percentage ratio of the metal complex to the fullerene is higher, it can be seen that the filling factor (FF) and power conversion efficiency (PCE) are reduced compared to Comparative Example 1, which contains only fullerene.

[0076] As a result, it can be confirmed that the performance of the solar cell device is improved in the first electron transport layer (61) in the range where the ratio of the metal complex to the fullerene is 0.1 at.% to 50 at.%, and in particular, it can be confirmed that the performance of the solar cell device is further improved in the range where the ratio of the metal complex to the fullerene is 0.1 at.% to 30 at.%.

[0077] Meanwhile, the thickness of the first electron transport layer (61) may be 5 nm to 30 nm, and more preferably 5 nm to 15 nm. At this time, if the thickness of the first electron transport layer (61) is less than 5 nm, it cannot form a thin film, so the effect of improving the density of the film cannot be expected, and it is difficult to control the work function value, and it is difficult to block holes generated from the perovskite photoactive layer (40), so electrons and holes recombine, which may reduce the performance of the device. If the thickness of the first electron transport layer (61) is more than 30 nm, the electron transport characteristics are reduced due to the light absorption characteristics of carbon materials such as fullerene-based materials, and thus the performance of the device may be reduced.

[0078] The second electron transport layer (62) may be formed on the first electron transport layer (61) and may include a metal oxide. For example, the metal oxide may have superior electron transport characteristics compared to fullerene-based materials. However, if it is located directly on the perovskite photoactive layer (40) containing a perovskite compound, there is a risk of oxidizing the perovskite compound, and since the energy band alignment with the perovskite compound is not correct, it may be difficult to extract electrons from the perovskite photoactive layer (40). Therefore, it is additionally formed on the first electron transport layer (61) so that electrons transferred from the first electron transport layer (61) can be received and easily transferred to the second electrode (80) described later, utilizing the excellent electron transport characteristics.

[0079] For example, the second electron transport layer (62) may include one or more selected from SnOx, TiOx, ZnOx, WOx, NbOx, InOx, AlOx, HfOx, BaSnOx, ZrOx, VOx, and CeOx, and specifically, may include SnOx.

[0080] At this time, the first electron transport layer (61) containing a hydrophobic fullerene-based material can exhibit excellent adhesion characteristics with the second electron transport layer (62) containing a metal oxide by further including a metal complexing agent.

[0081] Meanwhile, the second electron transport layer (62) can perform a process for forming a thin film at a relatively low temperature to prevent damage to the heat-sensitive fullerene-based material.

[0082] The second electron transport layer (62) can be formed using various methods, specifically at a low temperature using atomic layer deposition (ALD), and can stably secure the desired shape and characteristics.

[0083] Meanwhile, by using atomic layer deposition (ALD) to perform the thin film process at a low temperature, the perovskite photoactive layer (40) formed from a heat-sensitive perovskite compound can be prevented from being damaged by heat, thereby preventing a decrease in the performance of the solar cell device.

[0084] In an optional embodiment, a passivation layer (50) may be further disposed between the electron transport layer (60) and the perovskite photoactive layer (40).

[0085] The passivation layer (50) may include, for example, a passivation material, and this passivation material may serve to protect a perovskite-based compound included in the perovskite photoactive layer (40).

[0086] The passivation material may include one or more selected from, for example, LiF, KF, CsF, MgF2, AlOx, TiOx, HfOx, and ZrOx, and specifically examples may include LiF, KF, and CsF.

[0087] Meanwhile, if the passivation layer (50) contains alkali metals such as LiF, KF, and CsF, these alkali metals have small ion sizes and high mobility, so when the solar cell device is operated, they move a lot inside the device, which can have a negative effect on the performance and reliability of the device. At this time, the metal complexing agent included in the first electron transport layer (61) described above can suppress the movement of highly ionic alkali metals inside the device, thereby improving the performance and reliability of the device.

[0088] Meanwhile, metal complexes consist of a central metal ion coordinately bonded to an organic ligand, and this complex exhibits electron transfer properties due to the interaction between the metal core and the ligand. Additionally, due to their ability to bind to metal ions, they can be used for removing or separating metal ions. Therefore, if the passivation material contains alkali metals with small ion sizes, the metal complex can bind to these alkali metals to inhibit their interlayer migration within the device, thereby improving the performance and reliability of the device.

[0089] The transparent electrode (70) can be formed on the electron transport layer (60) using a conductive material that is transparent, and may include, for example, a transparent conductive oxide, a carbonaceous conductive material, and a metallic material. Examples of transparent conductive oxides may be used, such as ITO (Indium Tin Oxide), ICO (Indium Cerium Oxide), IWO (Indium Tungsten Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide), GITO (Gallium Indium Tin Oxide), GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine Tin Oxide), ZnO, etc. Carbonaceous conductive materials may include, for example, graphene or carbon nanotubes, and metallic materials may include, for example, metal (Ag) nanowires or metal thin films with a multilayer structure such as Au / Ag / Cu / Mg / Mo / Ti. In this specification, the term "transparent" refers to the ability to transmit light to a certain degree or more, and is not necessarily interpreted to mean complete transparency. The materials described above are not necessarily limited to the embodiments described above and can be formed from various materials, and their structures can also be varied, such as being single-layer or multilayer.

[0090] An anti-reflective film may be further included as an optional embodiment, and the anti-reflective film is placed on the transparent electrode (70) to prevent sunlight irradiated onto the perovskite solar cell (1) from being reflected, thereby improving the transmittance of sunlight and increasing the efficiency of the perovskite solar cell (1).

[0091] For example, the anti-reflective film may include fluorine (F), which has high light transmittance and a very low refractive index, and may include LiF as an optional embodiment.

[0092] The second electrode (80) can be formed on the transparent electrode (70) and can serve to electrically connect the perovskite solar cell (1) to the outside.

[0093] For example, the second electrode (80) can be formed from a metallic material such as silver (Ag), gold (Au), copper (Cu), magnesium (Mg), molybdenum (Mo), and titanium (Ti), and a pattern of a certain shape can be formed so that sunlight can enter into the cell.

[0094] As a result, the perovskite solar cell according to the embodiment of the present invention includes an organic material and a metal complex in the electron transport layer, thereby optimizing the energy band alignment between the electron transport layer and the perovskite light absorption layer, which can increase the power conversion efficiency of the solar cell device, and improves the density of the electron transport layer to improve adhesion with other layers, which can prevent delamination between thin films, thereby improving the stability and reliability of the solar cell device.

[0095] FIG. 2 is a cross-sectional view schematically illustrating an example of a tandem solar cell including a perovskite solar cell according to one embodiment of the present invention.

[0096] Referring to FIG. 2, a tandem solar cell (2) including a perovskite solar cell (2000) may include a silicon layer (120), a recombination layer (140) formed on the silicon layer (120), a perovskite photoactive layer (170), an electron transport layer (190) formed on the perovskite photoactive layer (170), and an electrode (210).

[0097] Additionally, the perovskite solar cell (2000) may further include one or more layers as an optional embodiment, for example, a hole transport layer (150) between the recombination layer (140) and the photoactive layer (170). Additionally, as an example, it may further include a passivation layer (180) between the photoactive layer (170) and the electron transport layer (190), and may further include a transparent electrode (200) disposed on the electron transport layer (190).

[0098] Additionally, as an optional embodiment, a SAM layer (160) disposed on the hole transport layer (150) may be further included, and one or more anti-reflection films disposed on the transparent electrode (200) may be further included.

[0099] Meanwhile, referring specifically to FIG. 2, the tandem solar cell (2) including a perovskite solar cell may include a silicon solar cell (lower cell) (1000) and a perovskite solar cell (upper cell) (2000) formed on the silicon solar cell (1000), and between the silicon solar cell (1000) and the perovskite solar cell (2000), a recombination layer (140) that joins the two and electrically connects them may be included.

[0100] This recombination layer (140) can be implemented using a transparent conductive oxide (TCO), a carbonaceous conductive material, a metallic material, or a conductive polymer so that long-wavelength light passing through the perovskite solar cell (2000) can be incident on the silicon solar cell (1000) placed underneath without transmission loss.

[0101] The silicon solar cell (1000) may be a silicon solar cell having a bandgap of approximately 1.0 eV to 1.2 eV. It may include a back electrode (ME) of a metal or metal alloy disposed on the substrate, a BSF layer (110) disposed on the back electrode (ME), a silicon layer (120) disposed on the BSF layer (110), and an emitter layer (130) disposed on the silicon layer (120).

[0102] At this time, the back electrode (ME) may include silver (Ag), titanium (Ti), gold (Au), etc.

[0103] The BSF (Back Surface Field) layer (110) is placed on the back electrode (ME) so that electrons and holes generated in the silicon layer (120) and the emitter layer (130) can be transferred to the outside through the back electrode (ME).

[0104] The silicon layer (120) is disposed on the BSF layer (110) and may have one of the known silicon solar cell semiconductor layer structures, but is not limited to a specific structure. For example, the silicon layer (120) may include a p-type amorphous or crystalline silicon layer (not shown), an n-type amorphous or crystalline silicon layer (not shown), and an amorphous intrinsic silicon layer (not shown).

[0105] The emitter layer (130) may include an n-type material or a p-type material depending on the material that is disposed on the silicon layer (120) and constitutes the recombination layer (140) described later.

[0106] According to such an embodiment of the present invention, the structure of the silicon solar cell (1000) is such that n on the surface of p-type silicon ++ Al-BSF (Aluminum Back Surface Field), PERC (Passivated Emitter and Rear Cell), PERT (Passivated Emitter Rear Totally Diffusing), and PERL (Passivated Emitter and Rear Locally Diffusing) structures or SiOx tunneling layer / n formed through emitter formation ++ It is not particularly limited because it can be a TOPCon (Tunnel oxide passivated contact) structure through poly-Si formation, etc.

[0107] A perovskite solar cell (2000) may include a perovskite photoactive layer (170) disposed on a recombination layer (140), an electron transport layer (190) formed on the perovskite photoactive layer (170), and an electrode (210).

[0108] Additionally, the perovskite solar cell (2000) may further include one or more layers as an optional embodiment, for example, a hole transport layer (150) between the recombination layer (140) and the photoactive layer (170). Additionally, as an example, it may further include a passivation layer (180) between the photoactive layer (170) and the electron transport layer (190), and may further include a transparent electrode (200) disposed on the electron transport layer (190).

[0109] Additionally, as an optional embodiment, a SAM layer (160) disposed on the hole transport layer (150) may be further included, and one or more anti-reflection films disposed on the transparent electrode (200) may be further included.

[0110] The recombination layer (140) can be formed from a conductive material, for example, a conductive material having light transparency, and may include, for example, a transparent conductive oxide, a carbonaceous conductive material and a metallic material. As a transparent conductive oxide, for example, ITO (Indium Tin Oxide), ICO (Indium Cerium Oxide), IWO (Indium Tungsten Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide), GITO (Gallium Indium Tin Oxide), GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine Tin Oxide), ZnO, etc. may be used. Carbonaceous conductive materials may include, for example, graphene or carbon nanotubes, and metallic materials may include, for example, metal (Ag) nanowires or metal thin films with a multilayer structure such as Au / Ag / Cu / Mg / Mo / Ti. In this specification, the term "transparent" refers to the ability to transmit light to a certain degree or more, and is not necessarily interpreted to mean complete transparency. The materials described above are not necessarily limited to the embodiments described above and can be formed from various materials, and their structures can also be varied, such as being single-layer or multilayer.

[0111] The hole transport layer (150) may be a layer formed on the recombination layer (140) to which holes generated in the perovskite photoactive layer (170) described later are transported. For example, the hole transport layer (150) may include one or more selected from tungsten oxide (WOx), molybdenum oxide (MoOx), vanadium oxide (V2O5), and nickel oxide (NiOx), and may also include at least one selected from the group consisting of monomolecular hole transport materials and polymeric hole transport materials, but is not limited thereto and any material used in the industry may be used. For example, spiro-MeOTAD [2,2',7,7'-tetrakis(N,Np-dimethoxy-phenylamino)-9,9'-spirobifluorene] may be used as the above-mentioned single-molecule hole transport material, and P3HT [poly(3-hexylthiophene)], PTAA (polytriarylamine), poly(3,4-ethylenedioxythiophene) or polystyrene sulfonate (PEDOT:PSS) may be used as the above-mentioned polymer hole transport material, but are not limited thereto.

[0112] Meanwhile, the hole transport layer (150) may further include a doping material. For example, the doping material may be a dopant selected from the group consisting of Li-based dopants, Co-based dopants, Cu-based dopants, Cs-based dopants, and combinations thereof, but is not limited thereto.

[0113] In an optional embodiment, a SAM layer (160) may be disposed on the hole transport layer (150).

[0114] The SAM layer (160) may include a self-assembled organic material having the characteristics of a p-type semiconductor and can improve the mobility characteristics of holes generated in the perovskite photoactive layer (170).

[0115] A photoactive layer (170) containing a perovskite-based material can be formed on a hole transport layer (150), and, for example, can perform the role of separating hole-electron pairs generated by receiving light energy from the sun into electrons or holes.

[0116] At this time, electrons formed in the perovskite photoactive layer (170) are transferred to the electron transport layer (190) described later, and holes formed in the perovskite photoactive layer (170) can be transferred to the hole transport layer (150).

[0117] For example, the perovskite photoactive layer (170) may include a perovskite-based material, and as a specific example, the perovskite-based material may have an organic-inorganic hybrid perovskite structure represented by the chemical formula ABX3 (wherein A may be a monovalent organic cation or metal cation, B may be a divalent metal cation, and X may be a halogen anion).

[0118] As a specific example, the perovskite photoactive layer (170) may include organic halide perovskites such as methyl ammonium iodide (MAI) and formamidinium iodide (FAI), or metal halide perovskites such as lead iodide (PbI2), bromine iodide (PbBr), and lead chloride (PbCl2), and may be a multilayer stacked structure including at least one of organic halide perovskites or metal halide perovskites. More specifically, the perovskite photoactive layer (40) may be CH3NH3PbI3, CH3NH3PbI x Cl 3-x , CH3NH3PbI x Br 3-x , CH3NH3PbCl x Br 3-x , HC(NH2)2PbI3, HC(NH2)2PbI x Cl 3-x , HC(NH2)2PbI xBr 3-x , HC(NH2)2PbCl x Br 3-x , (CH3NH3)(HC(NH2)2) 1-y PbI3, (CH3NH3)(HC(NH2)2) 1-y PbI x Cl 3-x , (CH3NH3)(HC(NH2)2) 1-y PbI x Br 3-x , or (CH3NH3)(HC(NH2)2) 1-y PbCl x Br 3-x It may include the back (0≤x, y≤1).

[0119] The electron transport layer (190) may be formed on the perovskite photoactive layer (170) and may include an electron transport material. For example, the electron transport material may include a metal oxide or an organic material, and when a hole-electron pair generated by receiving light energy from the sun is separated into an electron or a hole in the perovskite photoactive layer (170), the electron can be received and easily transferred to the electrode (210) described later.

[0120] In the second part, the electron transport layer (190) according to an embodiment of the present invention may include a first electron transport layer (191) and a second electron transport layer (192).

[0121] The first electron transport layer (191) may be disposed adjacent to the perovskite photoactive layer (170) and may include an organic material, the organic material may include, for example, a fullerene-based material. Additionally, the first electron transport layer (191) according to an embodiment of the present invention may further include a metal complexing agent. When the first electron transport layer (191) includes, for example, an organic material and a metal complexing agent, the first electron transport layer (191) can more easily receive electrons formed in the perovskite photoactive layer (170).

[0122] Additionally, the metal complex can be positioned to fill the empty spaces of the organic material, thereby improving the density of the first electron transport layer (191). For example, if the organic material includes a fullerene-based material, the organic material may have a spherical structure, and the metal complex can be positioned to fill the empty spaces of this spherical structure, thereby improving the density of the first electron transport layer (191).

[0123] As a specific example, the first electron transport layer (191) may include a fullerene-based material and a metal complex, wherein the metal complex may include, for example, one or more selected from Quinolinolato (8-Hydroxyquinoline) Complexes, β-Diketonates (Metal Acetylacetonates, M(acac)), Salen and Salophen Complexes, Porphyrin and Phthalocyanine Complexes, Ir(III) Complexes, Pt(II) Complexes, Pd(II) Complexes, Zn(II) Complexes, Ruthenium(II) Polypyridyl Complexes, Phthalocyanine Complexes and / or Crown Ethers and Cryptands.

[0124] As specific examples, Quinolinolato (8-Hydroxyquinoline) Complexes may include one or more selected from Liq (8-Quinolinolato Lithium), Alq (Aluminum tris(8-hydroxyquinoline)), Znq₂ (Zinc bis(8-hydroxyquinoline)), and Mgq₂ (Magnesium bis(8-hydroxyquinoline)); β-Diketonates may include one or more selected from Li(acac) (Lithium acetylacetonate), Al(acac)3 (Aluminum acetylacetonate), and Fe(acac)3 (Iron acetylacetonate); and Salen and Salophen Complexes may include one or more selected from Ni(Salen) (Nickel Salen Complex) and Co(Salen) (Cobalt Salen Complex).

[0125] In an optional embodiment, the first electron transport layer (191) may include fullerene and Liq (8-Quinolinolato Lithium).

[0126] Meanwhile, fullerenes are widely used as electron transport materials as excellent electron transport acceptors, but when fullerenes are used alone, they can be a factor that reduces the efficiency and stability of the device due to their molecular structure characteristics, such as higher LUMO levels and spherical structures compared to perovskite-based materials.

[0127] Specifically, in order for electrons formed in the perovskite photoactive layer (170) to move smoothly to the first electron transport layer (191), it must have a LUMO level similar to that of the perovskite photoactive layer (170). However, fullerene has a higher LUMO level than this, which can hinder the interlayer movement of electrons and become a factor that lowers the efficiency of the device.

[0128] In addition, due to the spherical structure of fullerenes, each carbon atom is completely bonded to three neighboring carbon atoms and therefore does not have unpaired electrons or unconnected bonds. While this bonding structure allows fullerene molecules to possess stability, it can be difficult for them to easily bond with other layers. Consequently, when external stress is applied, they become the most mechanically vulnerable parts, which can lead to mechanical stress or problems such as cracking and delamination during the manufacturing process.

[0129] To compensate for these problems, the first electron transport layer (191) according to an embodiment of the present invention may further include a metal complexing agent. By further including the metal complexing agent, the energy levels between the fullerene and the perovskite photoactive layer (170) can be matched, and the density of the thin film can be improved by filling the spherical fullerene structure, thereby improving the low adhesion of the thin film.

[0130] Meanwhile, metal complexes consist of a central metal ion coordinately bonded to an organic ligand, and due to the interaction between the metal core and the ligand, they possess electron transfer properties and can also have the property of binding to metal ions.

[0131] Due to the characteristics of this metal complex, the first electron transport layer (191) can achieve energy level optimization with the perovskite photoactive layer (170), and the adhesion is improved so that bonding with other layers can be easy.

[0132] Meanwhile, the ratio of the metal complex to the fullerene in the first electron transport layer (191) may be 0.1 at.% to 50 at.%, and more preferably 0.1 at.% to 30 at.%. At this time, if the ratio of the metal complex to the fullerene is less than 0.1 at.%, it may be difficult to match the energy band alignment with the perovskite photoactive layer, and if the ratio of the metal complex to the fullerene is more than 50 at.%, the insulation properties may be strengthened and the electron transport capability may be reduced.

[0133] Meanwhile, although both fullerene and metal complexing agents have electron transfer characteristics, in the structure of the first electron transfer layer (191), fullerene can exhibit superior electron transfer characteristics compared to metal complexing agents, so when the ratio of metal complexing agents to fullerene is 0.1 at.% to 30 at.%, the first electron transfer layer (191) can exhibit optimal electron transfer characteristics.

[0135] Type C60[Atomic percent, at%] Liq[Atomic percent, at%] Voc[V] Jsc[mA / cm 2 ] FF[%] PEC[%] Comparative Example 1 100 0 1.725 18.14 69.63 21.79 Comparative Example 2 0 100 1.696 17.26 46.24 13.54 Example 1 99.5 0.5 1.774 18.59 71.02 23.43 Example 2 90 10 1.807 18.54 73.50 24.62 Example 3 70 30 1.811 18.56 73.72 24.77 Example 4 50 50 1.780 18.45 70.73 23.23 Example 5 30 70 1.737 17.22 65.48 19.58 Example 6 10 90 1.720 17.24 65.58 19.44

[0136] Table 2 shows the parameters of the tandem solar cell device according to the atomic % ratio of the fullerene and metal complex in the first electron transport layer. Referring to Table 2, it can be seen that the open-circuit voltage (Voc), charge factor (FF), and power conversion efficiency (PCE) of the solar cell device in Examples 1 to 4, which contain both the fullerene and the metal complex, are all improved compared to Comparative Example 1 and Comparative Example 2, which contain only the fullerene and the metal complex, respectively. In particular, it can be seen that Example 3 exhibits the best performance with an open-circuit voltage (Voc) of 1.811 V, a charge factor (FF) of 73.72%, and a power conversion efficiency (PCE) of 24.77%.

[0137] Meanwhile, in the case of Examples 5 and 6, where the atomic percentage ratio of the metal complex to the fullerene is higher, it can be seen that the filling factor (FF) and power conversion efficiency (PCE) are reduced compared to Comparative Example 1, which contains only fullerene.

[0138] As a result, it can be confirmed that the performance of the solar cell device is improved in the first electron transport layer (191) in the range where the ratio of the metal complex to the fullerene is 0.1 at.% to 50 at.%, and in particular, it can be confirmed that the performance of the solar cell device is further improved in the range where the ratio of the metal complex to the fullerene is 0.1 at.% to 30 at.%.

[0139] Meanwhile, the thickness of the first electron transport layer (191) may be 5 nm to 30 nm, and more preferably 5 nm to 15 nm. At this time, if the thickness of the first electron transport layer (191) is less than 5 nm, it cannot form a thin film, so the effect of improving the density of the film cannot be expected, and it is difficult to control the work function value, and it is difficult to block holes generated from the perovskite photoactive layer (170), so electrons and holes recombine, which may reduce the performance of the device. If the thickness of the first electron transport layer (191) is greater than 30 nm, the electron transport characteristics are reduced due to the light absorption characteristics of carbon materials such as fullerene-based materials, and thus the performance of the device may be reduced.

[0140] The second electron transport layer (192) may be formed on the first electron transport layer (191) and may include a metal oxide. For example, the metal oxide may have superior electron transport characteristics compared to fullerene-based materials. However, if it is located directly on the perovskite photoactive layer (170) containing a perovskite compound, there is a risk of oxidizing the perovskite compound, and since the energy band alignment with the perovskite compound is not correct, it may be difficult to extract electrons from the perovskite photoactive layer (170). Therefore, it is additionally formed on the first electron transport layer (191) so that electrons transferred from the first electron transport layer (191) can be received and easily transferred to the second electrode (80) described later using the superior electron transport characteristics.

[0141] For example, the second electron transport layer (192) may include one or more selected from SnOx, TiOx, ZnOx, WOx, NbOx, InOx, AlOx, HfOx, BaSnOx, ZrOx, VOx, and CeOx, and specifically, may include SnOx.

[0142] At this time, the first electron transport layer (191) containing a hydrophobic fullerene-based material can exhibit excellent adhesion characteristics with the second electron transport layer (192) containing a metal oxide by further including a metal complexing agent.

[0143] Meanwhile, the second electron transport layer (192) can perform a process for forming a thin film at a relatively low temperature to prevent damage to the heat-sensitive fullerene-based material.

[0144] The second electron transport layer (192) can be formed using various methods, specifically at a low temperature using atomic layer deposition (ALD), and can stably secure the desired shape and characteristics.

[0145] Meanwhile, by using atomic layer deposition (ALD) to perform the thin film process at a low temperature, the perovskite photoactive layer (170) formed from a heat-sensitive perovskite compound can be prevented from being damaged by heat, thereby preventing a decrease in the performance of the solar cell device.

[0146] In an optional embodiment, a passivation layer (180) may be further disposed between the electron transport layer (190) and the perovskite photoactive layer (170).

[0147] The passivation layer (180) may include, for example, a passivation material, and this passivation material may serve to protect a perovskite-based compound included in the perovskite photoactive layer (170).

[0148] The passivation material may include one or more selected from, for example, LiF, KF, CsF, MgF2, AlOx, TiOx, HfOx, and ZrOx, and specifically examples may include LiF, KF, and CsF.

[0149] Meanwhile, if the passivation layer (180) contains alkali metals such as LiF, KF, and CsF, these alkali metals have small ion sizes and high mobility, so when the solar cell device is operated, they move a lot inside the device, which can have a negative effect on the performance and reliability of the device. At this time, the metal complexing agent included in the first electron transport layer (191) described above can suppress the movement of highly ionic alkali metals inside the device, thereby improving the performance and reliability of the device.

[0150] Meanwhile, metal complexes consist of a central metal ion coordinately bonded to an organic ligand, and this complex exhibits electron transfer properties due to the interaction between the metal core and the ligand. Additionally, due to their ability to bind to metal ions, they can be used for removing or separating metal ions. Therefore, if the passivation material contains alkali metals with small ion sizes, the metal complex can bind to these alkali metals to inhibit their interlayer migration within the device, thereby improving the performance and reliability of the device.

[0151] The transparent electrode (200) can be formed on the electron transport layer (190) using a conductive material that is transparent, and may include, for example, a transparent conductive oxide, a carbonaceous conductive material, and a metallic material. Examples of transparent conductive oxides may include ITO (Indium Tin Oxide), ICO (Indium Cerium Oxide), IWO (Indium Tungsten Oxide), ZITO (Zinc Indium Tin Oxide), ZIO (Zinc Indium Oxide), ZTO (Zinc Tin Oxide), GITO (Gallium Indium Tin Oxide), GIO (Gallium Indium Oxide), GZO (Gallium Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine Tin Oxide), ZnO, etc. Carbonaceous conductive materials may include, for example, graphene or carbon nanotubes, and metallic materials may include, for example, metal nanowires or multilayer metal thin films such as Au / Ag / Cu / Mg / Mo / Ti. In this specification, the term "transparent" refers to the ability to transmit light to a certain degree or more, and is not necessarily interpreted to mean complete transparency. The materials described above are not necessarily limited to the embodiments described above and can be formed from various materials, and their structures can also be varied, such as being single-layer or multilayer.

[0152] An anti-reflective film may be further included as an optional embodiment, and the anti-reflective film is placed on the transparent electrode (200) to prevent sunlight irradiated onto the perovskite solar cell (2000) from being reflected, thereby improving the transmittance of sunlight and increasing the efficiency of the perovskite solar cell (2000), and furthermore, can improve the efficiency of the tandem solar cell (2) including the perovskite solar cell (2000).

[0153] For example, the anti-reflective film may include fluorine (F), which has high light transmittance and a very low refractive index, and may include LiF as an optional embodiment.

[0154] The electrode (210) can be formed on the transparent electrode (200) and can serve to electrically connect the perovskite solar cell (2000) to the outside.

[0155] For example, the electrode (210) can be formed from a metallic material such as silver (Ag), gold (Au), copper (Cu), magnesium (Mg), molybdenum (Mo) and titanium (Ti), and can be formed in a grid pattern so that sunlight can enter the cell.

[0156] FIG. 3 is a cross-sectional view schematically illustrating another example of a tandem solar cell including a perovskite solar cell according to one embodiment of the present invention.

[0157] Referring to FIG. 3, a tandem solar cell (3) including a perovskite solar cell (2000') may include a silicon layer (120'), a recombination layer (140') formed on the silicon layer (120'), a perovskite photoactive layer (170'), an electron transport layer (190') formed on the perovskite photoactive layer (170'), and an electrode (210').

[0158] Additionally, the perovskite solar cell (2000') may include one or more additional layers as an optional embodiment, for example, a hole transport layer (150') between the recombination layer (140') and the photoactive layer (170'). Also, as an example, a transparent electrode (200') may be included between the composite layer (180') and the electrode (210').

[0159] Additionally, as an optional embodiment, a SAM layer (160') on the hole transport layer (150') may be further included.

[0160] Since the tandem solar cell (3) including the perovskite solar cell has the same configuration as the tandem solar cell (2) including the perovskite solar cell described above, a detailed description will be omitted, and only the parts that differ will be described.

[0161] A tandem solar cell (3) including a solar cell may include a form in which at least some layers are textured to improve light efficiency. By such textured at least some layers, an uneven surface is formed in the direction of incident light, and the light scattering effect of the light incident through the uneven surface increases the path of light incident on the perovskite photoactive layer (170'), thereby improving light collection and increasing the absorption rate of sunlight, and thereby achieving a high current value. At this time, the pyramid angle of the surface of the texturing may exceed 5°, and preferably, the pyramid angle of the surface may exceed 30°.

[0162] In addition, by placing an electron transport layer (190') containing an organic material and a metal complex on the perovskite photoactive layer (170'), the energy band alignment between the electron transport layer and the perovskite light absorption layer can be optimized, thereby increasing the power conversion efficiency of the solar cell device, and the density of the electron transport layer can be improved to improve adhesion with other layers, thereby preventing delamination between thin films and improving the stability and reliability of the solar cell device.

[0163] As such, the present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

[0164] The specific implementations described in the embodiments are examples and do not limit the scope of the embodiments in any way. For the sake of brevity of the specification, descriptions of conventional electronic configurations, control provision methods, software, and other functional aspects of said provision methods may be omitted. Additionally, the connections of lines or connecting members between components shown in the drawings are illustrative of functional connections and / or physical or circuit connections, and may be replaced or additionally represented as various functional connections, physical connections, or circuit connections in actual devices. Furthermore, unless specifically stated as "essential," "importantly," etc., a component may not be absolutely necessary for the application of the present invention.

[0165] In the specification of the embodiments (particularly in the claims), the use of the term "the above" and similar descriptive terms may be in both singular and plural. Furthermore, where a range is described in the embodiments, it is considered to include the invention with respect to individual values ​​within said range (unless otherwise stated), and is equivalent to describing each individual value constituting said range in the detailed description. Finally, regarding the steps constituting the method according to the embodiments, unless explicitly stated in order or otherwise stated, said steps may be performed in a suitable order. The embodiments are not necessarily limited by the order in which said steps are described. The use of any examples or exemplary terms (e.g., etc.) in the embodiments is merely for the purpose of describing the embodiments in detail, and the scope of the embodiments is not limited by said examples or exemplary terms unless limited by the claims. Furthermore, those skilled in the art will understand that various modifications, combinations, and changes may be made according to design conditions and factors within the scope of the claims or equivalents. Explanation of the symbols

[0166] 1: Solar cell 2, 3: Tandem solar cell 10: Substrate 20: First electrode 30: Hole transport layer 40: Perovskite photoactive layer 50: Passivation layer 60: Electron transport layer 70: Transparent electrode 80: Second electrode 110, 110': BSF layer 120, 120': Silicon layer 130, 130': Emitter layer 140, 140': Recombination layer 150, 150': Hole transport layer 160, 160': SAM layer 170, 170': Perovskite photoactive layer 180, 180': Passivation layer 190, 190': Electron transport layer 200, 200': Transparent electrode 210, 210': Electrode

Claims

Claim 1 A perovskite solar cell comprising: a substrate; a first electrode disposed on the substrate; a second electrode disposed opposite to the first electrode; a photoactive layer containing a perovskite-based material disposed between the first electrode and the second electrode; and an electron transport layer disposed between the photoactive layer and the second electrode and comprising an organic material and a metal complexing agent, wherein the metal complexing agent is disposed within the electron transport layer in the space between the organic materials. Claim 2 A perovskite solar cell according to claim 1, wherein the electron transport layer comprises a first electron transport layer and a second electron transport layer, wherein the first electron transport layer comprises an organic material and a metal complexing agent, and the second electron transport layer comprises a metal oxide. Claim 3 A perovskite solar cell according to claim 2, wherein the thickness of the first electron transport layer is 5 nm to 30 nm. Claim 4 In claim 1, the organic material comprises a fullerene-based material, a perovskite solar cell. Claim 5 A perovskite solar cell according to claim 1, wherein the metal complex comprises one or more selected from Quinolinolato (8-Hydroxyquinoline) Complexes, β-Diketonates (Metal Acetylacetonates, M(acac)), Salen and Salophen Complexes, Porphyrin and Phthalocyanine Complexes, Ir(III) Complexes, Pt(II) Complexes, Pd(II) Complexes, Zn(II) Complexes, Ruthenium(II) Polypyridyl Complexes, Phthalocyanine Complexes and / or Crown Ethers and Cryptands. Claim 6 In claim 5, the above Quinolinolato (8-Hydroxyquinoline) Complexes comprises one or more selected from Liq (8-Quinolinolato Lithium), Alq (Aluminum tris(8-hydroxyquinoline)), Znq₂ (Zinc bis(8-hydroxyquinoline)), and Mgq₂ (Magnesium bis(8-hydroxyquinoline)), a perovskite solar cell. Claim 7 A perovskite solar cell according to claim 1, wherein the organic material and the metal complexing agent comprise a ratio of the metal complexing agent to the organic material of 0.1 at.% to 50 at.%. Claim 8 A perovskite solar cell according to claim 1, further comprising a passivation layer disposed between the perovskite photoactive layer and the electron transport layer. Claim 9 A perovskite solar cell according to claim 8, wherein the passivation layer comprises a passivation material, and the metal complexing agent comprises bonding with the passivation material. Claim 10 In claim 9, the passivation material comprises one or more selected from LiF, KF, and CsF, in a perovskite solar cell. Claim 11 A tandem solar cell comprising: a silicon layer; a recombination layer on the silicon layer; an electrode disposed opposite to the recombination layer; a photoactive layer containing a perovskite-based material disposed between the recombination layer and the electrode; and an electron transport layer disposed between the electrode and the photoactive layer and comprising an organic material and a metal complexing agent, wherein the metal complexing agent is disposed within the electron transport layer in the space between the organic materials. Claim 12 A tandem solar cell according to claim 11, wherein the electron transport layer comprises a first electron transport layer and a second electron transport layer, wherein the first electron transport layer comprises an organic material and a metal complexing agent, and the second electron transport layer comprises a metal oxide. Claim 13 A tandem solar cell according to claim 12, wherein the thickness of the first electron transport layer is 5 nm to 30 nm. Claim 14 In paragraph 11, the above organic material is a tandem solar cell comprising a fullerene-based material. Claim 15 A tandem solar cell according to claim 11, wherein the metal complex comprises one or more selected from Quinolinolato (8-Hydroxyquinoline) Complexes, β-Diketonates (Metal Acetylacetonates, M(acac)), Salen and Salophen Complexes, Porphyrin and Phthalocyanine Complexes, Ir(III) Complexes, Pt(II) Complexes, Pd(II) Complexes, Zn(II) Complexes, Ruthenium(II) Polypyridyl Complexes, Phthalocyanine Complexes and / or Crown Ethers and Cryptands. Claim 16 In claim 15, the above Quinolinolato (8-Hydroxyquinoline) Complexes comprises one or more selected from Liq (8-Quinolinolato Lithium), Alq (Aluminum tris(8-hydroxyquinoline)), Znq₂ (Zinc bis(8-hydroxyquinoline)), and Mgq₂ (Magnesium bis(8-hydroxyquinoline)), forming a tandem solar cell. Claim 17 A tandem solar cell according to claim 11, wherein the organic material and the metal complexing agent comprise a ratio of the metal complexing agent to the organic material of 0.1 at.% to 50 at.%. Claim 18 A tandem solar cell according to claim 11, further comprising a passivation layer disposed between the perovskite photoactive layer and the electron transport layer. Claim 19 A tandem solar cell according to claim 18, wherein the passivation layer comprises a passivation material, and the metal complexing agent comprises bonding with the passivation material. Claim 20 In claim 19, the above passivation layer comprises one or more selected from LiF, KF, and CsF, forming a tandem solar cell.

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