KR102261523B1 - Perovskite solar cell and preparing method of the same - Google Patents

Abstract

The present application relates to a perovskite solar battery, which includes: a transparent substrate; an electron transport layer formed on the transparent substrate; a perovskite light absorption layer formed on the electron transport layer; a hole transport layer formed on the perovskite light absorption layer; and an electrode formed on the hole transport layer. An organic monolayer formed at the interface between the perovskite light absorption layer and the grain boundary and the hole transport layer is included, a hydrophilic group is formed on one surface of the organic monolayer, and a hydrophobic group is formed on the other surface, in the provided perovskite solar battery.

Description

Perovskite solar cell and manufacturing method thereof

The present application relates to a perovskite solar cell and a method for manufacturing the same.

A perovskite solar cell is a solar cell device that uses a material having a perovskite structure as a light absorber. It has high photoelectric conversion efficiency, low manufacturing cost, and advantages of low-temperature process and low-cost solution process. Since it has most of the characteristics required for solar cells, it is spotlighted as a next-generation solar cell to replace silicon solar cells.

However, although the photoelectric conversion efficiency has been greatly improved, the perovskite solar cell has environmental instability to light, heat, moisture and oxygen under operating conditions, making it very difficult to commercialize. In particular, it is interpreted that the severe degradation of perovskite solar cells in a humid environment is due to the hygroscopicity of organic cations and weak metal-halogen interactions. In addition, it is known that severe thermal stress under oxygen and moisture conditions promotes the degradation of solar cells due to the volatility of organic cations. In addition, formation of a deep trap by photoelectrons and reduction of halogens greatly deteriorates the photostability of the solar cell. Moreover, it is known that the decomposition of perovskite compounds begins at grain boundaries and surface defects when exposed to moisture or oxygen conditions.

Recently, research to improve the photoelectric conversion efficiency of perovskite solar cells is active. The most efficient structure in the perovskite solar cell is known as the nip structure, and in order to achieve the theoretical efficiency of 30% or more, a technology to effectively control the interface between the surface of the perovskite light absorption layer and the grain boundary is required. situation is necessary.

In this regard, there are attempts to control the interface by introducing a passivation layer, but it is difficult to form a uniform passivation layer between the perovskite interfaces, and additional heat treatment to form the passivation layer is required, and more than necessary The problem was that the passivation layer could be a limiting factor in reaching theoretical efficiency.

Accordingly, there is a need for a technology capable of manufacturing a perovskite solar cell having high efficiency and high stability while simplifying the process by overcoming the existing passivation layer forming technology.

Korean Patent Application Laid-Open No. 10-2019-0083957 relates to a perovskite solar cell having a structure in which each of the perovskite compound grains is surrounded by an organic capping agent, and the organic capping agent of the disclosed patent is disclosed. An ammonium functional group of (-NH ₃ ⁺ ) and an alkyl chain are attached to the metal-halogen terminated surface of a perovskite material, thereby improving the stability and photoelectric conversion efficiency of a solar cell. However, in the perovskite solar cell, a configuration including an organic monomolecular layer including the hydrophilic group and the hydrophobic group between the light absorption layer and the hole transport layer and the effect of effectively disposing the hydrophilic group and the hydrophobic group to improve water stability Recognized not doing

The present application provides a perovskite solar cell and a method for manufacturing the same as to solve the problems of the prior art described above.

However, the technical problems to be achieved by the embodiments of the present application are not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the first aspect of the present application, a transparent substrate; an electron transport layer formed on the transparent substrate; a perovskite light absorption layer formed on the electron transport layer; a hole transport layer formed on the perovskite light absorption layer; and an electrode formed on the hole transport layer, and an organic monolayer formed at an interface between the perovskite light absorption layer and the hole transport layer, wherein a hydrophilic group is formed on one surface of the organic monolayer, and a hydrophobic group is formed on the other surface. It provides a perovskite solar cell that is formed.

According to the exemplary embodiment of the present application, the perovskite light absorption layer may be formed on the hydrophilic group of the organic monolayer, and the hole transport layer may be formed on the hydrophobic group of the organic monolayer, but is not limited thereto.

According to one embodiment of the present application, the hydrophilic group may be combined with the perovskite light absorption layer to reduce surface defects of the perovskite light absorption layer, but is not limited thereto.

According to one embodiment of the present application, the organic monomolecules may include, but are not limited to, self-assembled monomolecules.

According to one embodiment of the present application, the organic monomer may include an alkylamine, but is not limited thereto.

According to one embodiment of the present application, the perovskite light absorption layer may include a perovskite material represented by the following formula (1), but is not limited thereto.

[Formula 1]

RMX ₃

In Formula 1, R is an alkali metal, a C _1-24 substituted or unsubstituted alkyl group, and when R is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, a nitro group or a methoxy group. and M is a metal cation selected from the group consisting of Pb, Sn, Ge, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, and combinations thereof, wherein X is It may include a halide anion or a chalcogenide anion, but is not limited thereto.

According to the exemplary embodiment of the present application, the transparent substrate is selected from the group consisting _{of FTO, ITO, IZO, ZnO-Ga 2} O ₃ , ZnO-Al ₂ O ₃ , SnO ₂ -Sb ₂ O _{3 , and combinations thereof.} It may include, but is not limited to.

According to the exemplary embodiment of the present application, the electron transport layer is TiO ₂ , ZrO, Al ₂ O ₃ , SnO ₂ , ZnO, WO ₃ , Nb ₂ O ₅ , TiSrO ₃ , and combinations thereof. may be, but is not limited thereto.

According to one embodiment of the present application, the hole transport layer is Spiro-OMeTAD, PEDOT:PSS, G-PEDOT, PANI:PSS, PANI:CSA, PDBT, P3HT, PCPDTBT, PCDTBT, PTAA, MoO ₃ , V ₂ O ₅ , NiO, WO ₃ , CuI, CuSCN, and may include one selected from the group consisting of combinations thereof, but is not limited thereto.

According to one embodiment of the present application, the electrode is selected from the group consisting of Au, Ag, Pt, Ni, Cu, In, Ru, Pd, Rh, Mo, Ir, Os, C, a conductive polymer, and combinations thereof. It may include, but is not limited to.

A second aspect of the present application, forming an electron transport layer on a transparent substrate; forming a perovskite light absorption layer on the electron transport layer; forming an organic monolayer on the perovskite light absorption layer; forming a hole transport layer on the organic monolayer; and forming an electrode on the hole transport layer. Including, a hydrophilic group is formed on one surface of the organic monolayer, and a hydrophobic group is formed on the other surface, providing a method of manufacturing a perovskite solar cell.

According to one embodiment of the present application, the organic monolayer may form a bond with the perovskite light absorption layer by self-assembly, but is not limited thereto.

According to one embodiment of the present application, the organic monolayer ^{may be formed under a pressure of 10 -4} torr to 10 ^-2 torr, but is not limited thereto.

According to one embodiment of the present application, the organic monolayer is spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof. It may be formed on the light absorption layer by a method selected from the group consisting of, but is not limited thereto.

According to one embodiment of the present application, the perovskite light absorption layer and the hole transport layer are spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing , electrospray, and may be formed by a method selected from the group consisting of combinations thereof, but is not limited thereto.

The above-described problem solving means are merely exemplary, and should not be construed as limiting the present application. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and detailed description.

According to the above-described means for solving the problems of the present application, the perovskite solar cell according to the present application forms an organic monolayer on the perovskite light absorption layer, thereby providing a highly efficient perovskite solar cell with improved moisture stability.

The perovskite solar cell according to the present application forms an organic monomolecular layer not only on the surface of the perovskite light absorption layer but also between the deep defects inevitably present in the perovskite light absorption layer, so a perfect blocking layer (passivation layer) can be formed. can

In this regard, in the method for manufacturing a perovskite solar cell according to the present application, the organic monomolecular layer is formed by penetrating the organic monomolecular to the inside of the defect through a low-vacuum process, so that a perfect passivation layer can be formed.

In the perovskite solar cell according to the present application, since the hydrophobic group present in the organic monolayer is disposed toward the outside from the surface of the perovskite light absorption layer, it is possible to effectively protect the perovskite light absorption layer from the external moisture environment.

By forming an organic monolayer in the method for manufacturing a perovskite solar cell according to the present application, it is easy for large-area coating and module processing when forming a hole transport layer.

However, the effects obtainable herein are not limited to the above-described effects, and other effects may exist.

1 is a schematic diagram of a perovskite solar cell according to an embodiment of the present application.
2 is a schematic diagram of a crystal structure of a perovskite material included in a perovskite light absorption layer of a perovskite solar cell according to an embodiment of the present application.
3 is a schematic diagram of the microstructure of the perovskite light absorption layer of the perovskite solar cell according to an embodiment of the present application.
4 is a flowchart of a method for manufacturing a perovskite solar cell according to an embodiment of the present application.
5 is an electron microscope (SEM) image taken to confirm the difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
6 is a result of X-ray photoelectron spectroscopy (XPS) performed to confirm the difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
7 is a result of X-ray photoelectron spectroscopy (XPS) performed to determine the difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
FIG. 8 is a result of X-ray photoelectron spectroscopy (XPS) for confirming a difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
9 is a result of X-ray photoelectron spectroscopy (XPS) performed to determine the difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
10 is a result of X-ray photoelectron spectroscopy (XPS) performed to confirm the difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
11 is an X-ray diffraction (XRD) analysis result for confirming a difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.
12 is a normalized power conversion efficiency (Normalized PCE) curve of the perovskite solar cell according to Examples and Comparative Examples of the present application.
13 is a current-voltage curve comparison result of perovskite solar cells according to Examples and Comparative Examples of the present application.
14 is a box chart of photoelectric parameters of perovskite solar cells according to Examples and Comparative Examples of the present application.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement them. However, the present application may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present application in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout this specification, when a part is "connected" to another part, this includes not only the case of being "directly connected", but also the case of being "electrically connected" with another element interposed therebetween. do.

Throughout this specification, when a member is positioned “on”, “on”, “on top”, “under”, “under”, or “under” another member, this means that a member is positioned on another member. It includes not only the case where they are in contact, but also the case where another member exists between two members.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used herein, the terms "about," "substantially," and the like are used in or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid in the understanding of the present application. Accurate or absolute figures are used to prevent unconscionable infringers from using the mentioned disclosures unfairly. Also, throughout this specification, "step to" or "step to" does not mean "step for".

Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include one or more selected from the group consisting of.

Throughout this specification, reference to “A and/or B” means “A, B, or A and B”.

Hereinafter, the perovskite solar cell of the present application will be described in detail with reference to embodiments and examples and drawings. However, the present application is not limited to these embodiments and examples and drawings.

As a technical means for achieving the above technical problem, the first aspect of the present application, a transparent substrate; an electron transport layer formed on the transparent substrate; a perovskite light absorption layer formed on the electron transport layer; a hole transport layer formed on the perovskite light absorption layer; and an electrode formed on the hole transport layer, and an organic monolayer formed at the interface between the perovskite light absorption layer and the hole transport layer, wherein a hydrophilic group is formed on one surface of the organic monolayer, and on the other surface It provides a perovskite solar cell that a hydrophobic group is formed.

Hereinafter, a monomolecular means a single molecule or a molecule that has unique properties and can act as a unit, and a monomolecular layer refers to a state in which molecules form a layer with a thickness of one molecule on the surface of any solid or liquid. it means.

1 is a schematic diagram of a perovskite solar cell according to an embodiment of the present application.

According to the exemplary embodiment of the present application, the perovskite light absorption layer 300 is formed on the hydrophilic group of the organic monomolecular layer 400 , and the hole transport layer 500 is formed on the hydrophobic group of the organic monomolecular layer 400 . It may be formed in, but is not limited thereto.

In this regard, the organic monolayer 400 includes a material having a hydrophilic group and a hydrophobic group. For example, the organic monolayer 400 may include an organic compound having a hydrophilic group, and a portion of the organic compound excluding the hydrophilic group may function as a hydrophobic group.

According to one embodiment of the present application, the organic monomer may include an alkylamine, but is not limited thereto.

The alkylamine has a structure in which a hydrogen (H) atom of a saturated or unsaturated aliphatic hydrocarbon is substituted with an amine group, and the alkylamine may include an alkylamine commonly referred to as a fatty amine.

For example, the organic monomolecule is oleylamine, dodecylamine, dioctylamine, tetradecylamine, methylamine, ethylamine, propyl Amine (Propylamine), butylamine (Butylamine), pentylamine (Pentylamine), hexylamine (Hexylamine), heptylamine (Heptylamine), octylamine (Octylamine), nonylamine (Nonylamine), decylamine (Decylamine), and their It may be an alkylamine selected from the group consisting of combinations, but is not limited thereto.

As the number of carbon atoms of the alkyl group increases, the hydrophobicity of the hydrophobic group on the organic monolayer increases, and thus the stability of the perovskite solar cell according to the present application may be improved.

However, hereinafter, for convenience of description, the organic monomolecules are limited to those mainly corresponding to oleylamine.

Oleylamine has the following structure:

In the structure, the amine group has hydrophilicity, and the carbon chain portion has hydrophobicity. Specifically, the oleylamine _{is an organic compound having the molecular formula C 18} H ₃₅ NH ₂ , and has a structure in which the carboxyl group (-COOH) of oleic acid, a type of monounsaturated fatty acid, is substituted with an amine group. In the above structure, the amine group acts as a polar (hydrophilic) head and the carbon chain acts as a non-polar (hydrophobic) tail, so that the oleylamine can function as a surfactant.

As will be described later, due to the structural characteristics of oleylamine, the perovskite solar cell according to the present application binds the amine group to the defect 310 present on the crystal surface of the perovskite light absorption layer 300 . It is possible to reduce the defects 310, and thus there is a phase stabilization effect of the perovskite crystal. In addition, since the carbon chain having the hydrophobicity is directed outward from the perovskite light absorption layer 300 , it is possible to protect the perovskite light absorption layer 300 from moisture.

The organic monolayer 400 may be formed at the interface between the perovskite light absorption layer 300 and the hole transport layer 500 as described above, and the hydrophilic group included in the organic monolayer 400 may be the light The hydrophobic groups oriented in the absorption layer 300 and included in the organic monomolecular layer 400 are oriented in the hole transport layer 500 .

Moreover, the hydrophilic group of the organic monomolecular layer 400 may be oriented in the perovskite light absorption layer 300 to form a bond with the perovskite light absorption layer 300 .

According to one embodiment of the present application, the organic monomolecules may include, but are not limited to, self-assembled monomolecules.

The self-assembly means that disorderly elements form an organizational structure or form spontaneously by interaction between the elements without an external instruction.

In this regard, as will be described later in the second aspect of the present application, in the method for manufacturing a perovskite solar cell according to the present application, the organic monomolecules dispersed in a solvent and present in disorder are merely perovskite without a separate treatment. By dispersing the organic solution containing the organic monomolecules on the light absorption layer 300 , the organic monomolecular layer 400 is automatically formed by interaction with the perovskite light absorption layer 300 .

Specifically, the hydrophilic group of the organic monomolecular layer 400 may be combined with the perovskite light absorption layer 300 in a self-assembly manner. That is, the organic monolayer 400 may be a self-assembled monolayer (SAM). The bond includes a covalent bond.

According to one embodiment of the present application, the hydrophilic group may be combined with the perovskite light absorption layer 300 to reduce the surface defects 310 of the perovskite light absorption layer 300, but is limited thereto it is not

In particular, the organic monomolecules may be formed at the interface between the perovskite light absorption layer 300 and the hole transport layer 500 as well as defects 310 present on the surface of the perovskite light absorption layer 300 . It may also be formed on the organic monolayer 400 to form the organic monolayer 400 .

2 is a schematic diagram of the crystal structure of the perovskite material 320 included in the perovskite light absorption layer 300 of the perovskite solar cell according to an embodiment of the present application.

3 is a schematic diagram of the microstructure of the perovskite light absorption layer 300 of the perovskite solar cell according to an embodiment of the present application.

In this regard, the perovskite light absorption layer 300 includes a perovskite material 320, which inevitably contains defects 310 because the perovskite material 320 forms crystals. . The defect 310 refers to a region in which the arrangement of atoms in the crystal is partially disturbed, and since the physical properties of the crystal can be greatly changed, control of the defect 310 is essential.

The defect 310 includes a grain boundary and a vacancy, and the vacancy 310 may include, for example, a cation vacancy, an anion vacancy, an atomic vacancy, etc., but is not limited thereto. .

For example, the cation vacancies may be V _Cs ⁺ , V _Cs ²⁺ , V _FA ⁺ , V _MA ⁺ , V _Pb ⁺ , V _Pb ²⁺ , and the anion vacancies may be V _I ^- , V _Br ^- , However, the present invention is not limited thereto.

Referring to FIG. 3, cation vacancies, anion vacancies, and grain boundaries are illustratively illustrated as defects 310 present on the perovskite light absorption layer 300, but the controllable defects 310 herein are not limited

The perovskite solar cell according to the present application forms the organic monomolecules on the defects 310 present in the perovskite light absorption layer 300, thereby reducing the defects of the perovskite light absorption layer 300. can be controlled

In this regard, since the defect 310 includes the positive ion vacancies and the anion vacancies bearing a charge, the hydrophilic group (polarity) included in the organic monomolecule may easily interact with the defect 310 .

In addition, hydrophobic groups present in the organic monomolecular layer 400 are aligned in the hole transport layer 500 as described above. That is, since the hydrophobic group is disposed to face the outside from the surface of the perovskite light absorption layer 300, it is possible to effectively protect the perovskite light absorption layer 300 from an external moisture environment.

That is, by including the organic monolayer 400 , it is possible to control the defects 310 of the perovskite light absorption layer 300 , and to dramatically improve water stability.

Conventional perovskite solar cells are vulnerable to a moisture environment, so there is a problem in that the perovskite material included in the perovskite light absorption layer is decomposed by moisture. As such, when the perovskite material is decomposed, the power conversion efficiency (PCE) of the perovskite solar cell is significantly reduced.

On the other hand, the perovskite solar cell according to the present application may have excellent moisture stability by including the organic monolayer 400, and thus may stably maintain high photoelectric conversion efficiency.

In addition, the organic monolayer 400 may function as a passivation (passivation) layer by effectively controlling the defects 310 and improving moisture stability as described above.

According to one embodiment of the present application, the perovskite light absorption layer may include a perovskite material represented by the following formula (1), but is not limited thereto.

[Formula 1]

RMX ₃

In Formula 1, R is an alkali metal, a C _1-24 substituted or unsubstituted alkyl group, and when R is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, a nitro group, or a methoxy group. and M is a metal cation selected from the group consisting of Pb, Sn, Ge, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, and combinations thereof, wherein X is It may include a halide anion or a chalcogenide anion, but is not limited thereto.

According to the exemplary embodiment of the present application, the transparent substrate is selected from the group consisting _{of FTO, ITO, IZO, ZnO-Ga 2} O ₃ , ZnO-Al ₂ O ₃ , SnO ₂ -Sb ₂ O _{3 , and combinations thereof.} It may include, but is not limited to.

According to the exemplary embodiment of the present application, the electron transport layer is TiO ₂ , ZrO, Al ₂ O ₃ , SnO ₂ , ZnO, WO ₃ , Nb ₂ O ₅ , TiSrO ₃ , and combinations thereof. may be, but is not limited thereto.

According to one embodiment of the present application, the hole transport layer is Spiro-OMeTAD, PEDOT:PSS, G-PEDOT, PANI:PSS, PANI:CSA, PDBT, P3HT, PCPDTBT, PCDTBT, PTAA, MoO ₃ , V ₂ O ₅ , NiO, WO ₃ , CuI, CuSCN, and may include one selected from the group consisting of combinations thereof, but is not limited thereto.

According to one embodiment of the present application, the electrode is selected from the group consisting of Au, Ag, Pt, Ni, Cu, In, Ru, Pd, Rh, Mo, Ir, Os, C, a conductive polymer, and combinations thereof. It may include, but is not limited to.

A second aspect of the present application, the steps of forming an electron transport layer 200 on the transparent substrate 100; forming a perovskite light absorption layer 300 on the electron transport layer 200; forming an organic monolayer 400 on the perovskite light absorption layer 300; forming a hole transport layer 500 on the organic monolayer 400; and forming an electrode 600 on the hole transport layer 500 ; Including, a hydrophilic group is formed on one surface of the organic monolayer, and a hydrophobic group is formed on the other surface, providing a method of manufacturing a perovskite solar cell.

With respect to the method for manufacturing a perovskite solar cell according to the second aspect of the present application, detailed descriptions of parts overlapping with the first aspect of the present application are omitted, but even if the description is omitted, the contents described in the first aspect of the present application can be equally applied to the second aspect of the present application.

4 is a flowchart of a method for manufacturing a perovskite solar cell according to an embodiment of the present application.

First, the electron transport layer 200 is formed on the transparent substrate 100 (S100).

Then, the perovskite light absorption layer 300 is formed on the electron transport layer 200 (S200).

The perovskite light absorption layer 300 may be formed by applying a solution including a perovskite light absorption layer precursor material on the electron transport layer 200 .

According to one embodiment of the present application, the perovskite light absorption layer 300 is spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing, It may be formed by a method selected from the group consisting of electrospray, and combinations thereof, but is not limited thereto.

The perovskite light absorption layer 300 may be formed by additionally performing heat treatment at 100° C. to 200° C., but is not limited thereto. Preferably, the perovskite light absorption layer 300 may be formed by heat treatment at a temperature of about 150 ℃.

Next, an organic monolayer 400 is formed on the perovskite light absorption layer 300 (S300).

The organic monomolecular layer 400 may be formed by applying an organic solution containing an organic compound such as a material containing a hydrophilic group and a hydrophobic group as described above, for example, oleylamine.

The organic solution may be formulated at a concentration of about 20 mg/ml or less, but is not limited thereto. Preferably, the organic solution may have a concentration of about 20 mg/ml, and when the organic solution has a concentration of about 20 mg/ml or less, the photoelectric conversion efficiency may increase as the concentration increases. .

When the organic solution is formulated at a concentration of about 20 mg/ml or more, the photoelectric conversion efficiency may decrease due to the formation of an excessive organic layer (organic monolayer 400 ).

According to one embodiment of the present application, the organic monolayer 400 is spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing, electrospray, and It may be formed on the perovskite light absorption layer 300 by a method selected from the group consisting of combinations thereof, but is not limited thereto.

According to the exemplary embodiment of the present application, the organic monomolecular layer 400 may form a bond with the perovskite light absorption layer 300 by self-assembly, but is not limited thereto. The bonding may be formed on the hydrophilic group of the organic monomolecular layer 400 and the defect 310 of the perovskite light absorption layer 300, but is not limited thereto.

In the method for manufacturing a perovskite solar cell according to the present application, a bond with the organic monolayer 400 is automatically formed on the perovskite light absorption layer 300 by simply applying the organic solution without an additional process. That is, it means that the organic monomolecular layer 400 forms a self-assembled self-assembled monomolecular film (SAM) on the organic monomolecular layer 400 .

According to the exemplary embodiment of the present application, the organic monolayer 400 ^{may be formed under a pressure of 10 −3} torr to 10 ⁻² torr, but is not limited thereto.

The step of forming the organic monomolecular layer 400 is performed under a low vacuum (referred to as a low vacuum process), thereby effectively forming the monomolecular layer 400 on defects present in the perovskite light absorption layer 300 . have. The low vacuum ^{means a pressure condition of 10 −3} torr to 10 ⁻² torr, and preferably, the low vacuum may be about 10 ⁻² torr.

The low vacuum process may be performed for about 10 minutes, but is not limited thereto.

The step of forming the organic monolayer 400 may be sequentially performing the low-vacuum process after performing the process of applying the organic solution, but is not limited thereto.

In this regard, after the organic solvent is applied on the perovskite light absorption layer 300, an organic monomolecular layer 400 is primarily formed, and at this time, an excess solvent is formed on the perovskite light absorption layer 300. and bubbles may remain.

When an organic monolayer is formed by simply applying an organic solvent, it is difficult for the organic solvent to penetrate into the deep defects 310 such as grain boundaries due to the residual solvent and air bubbles.

In the method for manufacturing a perovskite solar cell according to the present application, the residual solvent or bubbles present on the perovskite light absorption layer 300 can be removed by performing the low vacuum process, so that the perovskite light The organic solvent may penetrate even into the deep defect 310 in the absorption layer 300 to form the organic monolayer 400 on the defect 310 secondarily. Accordingly, in the method of manufacturing a perovskite solar cell according to the present application, a passivation layer that perfectly controls the defects 310 of the perovskite light absorption layer 300 may be formed.

In addition, since the passivation effect is improved by forming the organic monolayer 400 under the low vacuum, the photoelectric conversion efficiency of the perovskite solar cell can be improved.

Then, the hole transport layer 500 is formed on the organic monolayer 400 (S400).

The hole transport layer 500 may be formed by applying a hole transport layer material solution on the organic monolayer 400 , and the hole transport layer material solution may be non-polar (hydrophobic).

The method for manufacturing a perovskite solar cell according to the present application facilitates large-area coating and module processes due to the affinity with the hydrophobic group of the hole transport layer material solution and the organic monolayer 400 .

According to one embodiment of the present application, the hole transport layer 500 is spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing, electrospray, and It may be formed by a method selected from the group consisting of combinations thereof, but is not limited thereto.

Next, an electrode 600 is formed on the hole transport layer 500 (S500).

The electrode 600 may be formed under a high vacuum, but is not limited thereto. The high vacuum means a pressure condition ^{of about 10 -6 torr.}

The electrode 600 is formed by sputtering, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), e-beam evaporation, thermal deposition, vacuum thermal deposition, and plasma deposition. , and may be formed by a method selected from the group consisting of combinations thereof, but is not limited thereto.

The present invention will be described in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[Example] Preparation of perovskite solar cells (Au/Spiro-OMeTAD/OLA/Pev/TiO ₂ /FTO)

_{Chemical bath deposition was performed with a 0.165 M TiCl 4} solution on a transparent conductive substrate (F-doped SnO ₂ , FTO) at 70° C. for 45 minutes to form a very thin thin film, and then at 150° C. for 60 minutes. Heat treatment was performed to form a metal oxide electron transport layer (TiO _{2 ) (TiO 2} /FTO).

_{Then, a perovskite light absorption layer precursor solution having a composition of (FAPbI 3} ) _0.83 (MAPbBr ₃ ) _0.12 (CsPbI ₃ ) _{0.05 at} a concentration of 1.6 M was added to 20.9 mg of CsI, 229.8 mg of FAI, 653.2 mg of PbI ₂ , 21.6 mg of MABr, 70.9 mg of PbBr ₂ , and 32.3 mg of MACl were prepared by dissolving in DMF:DMSO (7:3, v/v, total 1 ml). Then, 72.3 mg of Spiro-OMeTAD was dissolved in 1 ml of chlorobenzene to form a Spiro-OMeTAD solution. Then, 180 mg of Li-TFSI was dissolved in 250 ml of acetonitrile to form a Li-TFSI solution. A hole transport layer material solution was prepared by dissolving 28.8 μl of 4-tert-butylpyridine and 17.6 μl of the Li-TFSI solution in the Spiro-OMeTAD solution.

Then, the perovskite light absorption layer precursor solution was spin-coated on the substrate (FTO) and heat-treated at a temperature of 150° C. for 10 minutes to obtain a perovskite light absorption layer (FA _0.83 MA _0.12 Cs _0.05 PbI _2.64 Br _0.36 , Pev). ) was formed (Pev/TiO ₂ /FTO).

Then, an organic solution of 20 mg/ml was prepared by adding oleylamine to a toluene solvent.

Then, the organic solution is spin-coated on the surface of the perovskite light absorption layer (Pev) of the Pev/TiO ₂ /FTO, and the substrate is subjected to a low vacuum treatment under ^{10 -3 torr for 10 minutes.} Thereafter, an organic monolayer (OLA) was formed by spin-coating a non-polar solvent to remove the residual organic solution (OLA/Pev/TiO ₂ /FTO).

5 is an electron microscope (SEM) image taken to confirm a difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.

Specifically, (a) and (b) of Fig. 5 are the surface (Pev/TiO ₂ /FTO) of the perovskite light absorption layer before the formation of the organic monolayer was photographed at magnifications of x50,000 and x100,000, respectively. Electron microscope (SEM) images, (c) and (d) are the surface (OLA/Pev/TiO ₂ /FTO) after forming an organic monolayer on the surface of the perovskite light absorption layer x50,000 and x100, respectively, This is an electron microscope (SEM) image taken at a magnification of 000.

Referring to FIG. 5 , it can be confirmed that the organic monolayer is formed (OLA/Pev/TiO ₂ /FTO) on the perovskite light absorption layer (Pev/TiO ₂ /FTO), thereby making the surface uniform. Through this, it can be seen that the interfacial defects present on the perovskite light absorption layer (Pev) can be overcome by introducing the organic monolayer (OLA).

6 to 10 are X-ray photoelectron spectroscopy (XPS) results for confirming the difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application. . The electronic structure of the surface and the interface was measured through the X-ray photoelectron spectroscopy.

Specifically, FIG. 6 is a 1s orbital electron of a carbon (C) element, FIG. 7 is a 1s orbital electron of a nitrogen (N) element, FIG. 8 is a 4f orbital electron of a lead (Pb) element, and FIG. 9 is an iodine (I) element of 3d orbital electrons, FIG. 10 is a graph of analysis results for 3d orbital electrons of bromine (Br) element. The elements (C, N, Pb, I, Br) are elements present in the perovskite light absorption layer.

Referring to this, the increased binding energy of the Pev / TiO ₂ / FTO in OLA / Pev / TiO ₂ / FTO the organic monolayer (OLA) formed relative to the element (C, N, Pb, I, Br) can be checked Through this, it can be seen that a bond is formed between the perovskite light absorption layer (Pev) and the organic monolayer (OLA). The organic monolayer (OLA) may be formed to control defects and stabilize the phase of the perovskite crystal.

Then, the hole transport layer material solution was spin-coated on the surface of the organic monolayer (OLA) of OLA/Pev/TiO ₂ /FTO to form a hole transport layer (Spiro-OMeTAD) (Spiro-OMeTAD/OLA/Pev/TiO _{2 )} /FTO).

^{Then, gold (Au) is deposited under a high vacuum (10 -6} torr) to a thickness of 50 nm or more on the surface of the hole transport layer (Spiro-OMeTAD) of the Spiro-OMeTAD/OLA/Pev/TiO ₂ /FTO, and the electrode (Au) ) (Au/Spiro-OMeTAD/OLA/Pev/TiO ₂ /FTO).

[Comparative Example 1] Preparation of a perovskite solar cell (Au/Spiro-OMeTAD/Pev/TiO ₂ /FTO)

_{Chemical bath deposition was performed with a 0.165 M TiCl 4} solution on a transparent conductive substrate (F-doped SnO ₂ , FTO) at 70° C. for 45 minutes to form a very thin thin film, and then at 150° C. for 60 minutes. Heat treatment was performed to form a metal oxide electron transport layer (TiO _{2 ) (TiO 2} /FTO).

Then, a perovskite light absorption layer precursor solution having a composition of 1.6 M concentration of (FAPbI ₃ ) _0.83 (MAPbBr ₃ ) _0.12 (CsPbI ₃ ) _0.05 was added to 20.9 mg of CsI, 229.8 mg of FAI, 653.2 mg of PbI ₂ , 21.6 mg of MABr, 70.9 mg of PbBr ₂ , and 32.3 mg of MACl were prepared by dissolving in DMF:DMSO (7:3, v/v, total 1 ml). Then, 72.3 mg of Spiro-OMeTAD was dissolved in 1 ml of chlorobenzene to form a Spiro-OMeTAD solution. Then, 180 mg of Li-TFSI was dissolved in 250 ml of acetonitrile to form a Li-TFSI solution. A hole transport layer material solution was prepared by dissolving 28.8 μl of 4-tert-butylpyridine and 17.6 μl of the Li-TFSI solution in the Spiro-OMeTAD solution.

Subsequently, the perovskite light absorption layer precursor solution was spin-coated on the substrate (FTO) and heat-treated at a temperature of 150° C. for 10 minutes to form a perovskite light absorption layer (Pev) (Pev/TiO ₂ /FTO) ).

Subsequently, the hole transport layer material solution was spin-coated on the surface of the perovskite light absorption layer (Pev) of the Pev/TiO _{2 /FTO to form a hole transport layer (Spiro-OMeTAD) (Spiro-OMeTAD/Pev/TiO 2 )} /FTO).

^{Then, gold (Au) is deposited under high vacuum (10 -6} torr) to a thickness of 50 nm or more on the surface of the hole transport layer (Spiro-OMeTAD) of the Spiro-OMeTAD/Pev/TiO ₂ /FTO to form an electrode (Au) formed (Au/Spiro-OMeTAD/Pev/TiO ₂ /FTO).

[Comparative Example 2] Preparation of perovskite solar cell (Au/Spiro-OMeTAD/OLA'/Pev/TiO ₂ /FTO) - Low vacuum process not performed

_{Chemical bath deposition was performed with a 0.165 M TiCl 4} solution on a transparent conductive substrate (F-doped SnO ₂ , FTO) at 70° C. for 45 minutes to form a very thin thin film, and then at 150° C. for 60 minutes. Heat treatment was performed to form a metal oxide electron transport layer (TiO _{2 ) (TiO 2} /FTO).

_{Then, a perovskite light absorption layer precursor solution having a composition of (FAPbI 3} ) _0.83 (MAPbBr ₃ ) _0.12 (CsPbI ₃ ) _{0.05 at} a concentration of 1.6 M was added to 20.9 mg of CsI, 229.8 mg of FAI, 653.2 mg of PbI ₂ , 21.6 mg of MABr, 70.9 mg of PbBr ₂ , and 32.3 mg of MACl were prepared by dissolving in DMF:DMSO (7:3, v/v, total 1 ml). Then, 72.3 mg of Spiro-OMeTAD was dissolved in 1 ml of chlorobenzene to form a Spiro-OMeTAD solution. Then, 180 mg of Li-TFSI was dissolved in 250 ml of acetonitrile to form a Li-TFSI solution. A hole transport layer material solution was prepared by dissolving 28.8 μl of 4-tert-butylpyridine and 17.6 μl of the Li-TFSI solution in the Spiro-OMeTAD solution.

Then, the perovskite light absorption layer precursor solution was spin-coated on the substrate (FTO) and heat-treated at a temperature of 150° C. for 10 minutes to obtain a perovskite light absorption layer (FA _0.83 MA _0.12 Cs _0.05 PbI _2.64 Br _0.36 , Pev). ) was formed (Pev/TiO ₂ /FTO).

Then, an organic solution of 20 mg/ml was prepared by adding oleylamine to a toluene solvent.

Then, the organic solution was spin-coated on the surface of the perovskite light absorption layer (Pev) of the Pev/TiO ₂ /FTO and the remaining organic solution was removed to form an organic monolayer (OLA') (OLA'/Pev/TiO). ₂ /FTO).

Then, the hole transport layer material solution was spin-coated on the surface of the organic monolayer (OLA') of OLA'/Pev/TiO ₂ /FTO to form a hole transport layer (Spiro-OMeTAD) (Spiro-OMeTAD/OLA'/Pev) /TiO ₂ /FTO).

^{Then, gold (Au) is deposited under high vacuum (10 -6} torr) to a thickness of 50 nm or more on the surface of the hole transport layer (Spiro-OMeTAD) of the Spiro-OMeTAD/OLA'/Pev/TiO ₂ /FTO and the electrode ( Au) was formed (Au/Spiro-OMeTAD/OLA'/Pev/TiO ₂ /FTO).

[Experimental Example 1-1] Water Stability of Perovskite Light Absorption Layer

_{The Pev/TiO 2} /FTO and the OLA/Pev/TiO ₂ /FTO obtained during the manufacturing process of Examples were exposed to a moisture environment (humidity 50%) for 50 days, respectively, and the moisture of the perovskite light absorption layer according to the number of days elapsed Stability was confirmed.

11 is an X-ray diffraction (XRD) analysis result for confirming a difference according to the presence/absence of an organic monolayer in the perovskite solar cell according to an embodiment of the present application.

_{11, in the Pev/TiO 2} /FTO in which the organic monomolecular layer (OLA) is not formed, the perovskite light absorption layer (Pev) is decomposed from the first day after exposure to a moisture environment, and PbI ₂ is detected, It can be seen that the peak of _{detected PbI 2} increases as time elapses after exposure to a moisture environment. On the other hand, in the OLA/Pev/TiO ₂ /FTO in which the organic monolayer (OLA) is formed, it can be seen that _{PbI 2} is not detected even after 50 days have elapsed after exposure to a moisture environment.

[Experimental Example 1-2] Moisture stability of perovskite solar cells

The normalized efficiency (Normalized PCE) curve was obtained according to the elapsed time while exposing the perovskite solar cells prepared according to Examples and Comparative Examples to a moisture environment (humidity 50%) for 1,000 hours, respectively.

12 is a normalized power conversion efficiency (Normalized PCE) curve of the perovskite solar cell according to Examples and Comparative Examples of the present application.

Referring to FIG. 12 , it can be confirmed that the perovskite solar cell (Example) including the organic monolayer (OLA) maintains the efficiency of 80% or more of the initial efficiency even after 1,000 hours have elapsed after exposure to a moisture environment. . It can be seen that the conventional perovskite solar cell (comparative example) achieves the initial efficiency of about 60% when 1,000 hours have elapsed after exposure to a moisture environment, through which the perovskite solar cell according to the present application excellent moisture stability of

In addition, comparing FIGS. 11 and 12, the perovskite light absorbing layer (OLA/Pev/TiO ₂ /FTO) on which the organic monolayer (OLA) is formed in FIG. 11 is exposed to a moisture environment (humidity 50%) for 50 days. Since it was confirmed that the decomposition did not occur, the perovskite solar cell (Au/Spiro-OMeTAD/OLA/Pev/TiO ₂ /FTO) of the embodiment in FIG. 12 showed a decrease in efficiency of about 20% after exposure to a moisture environment. It can be seen that this is due to the influence of moisture on the organic material included in the hole transport layer (Spiro-OMeTAD). That is, by including the organic monolayer, the perovskite light absorption layer (Pev) can still effectively obtain moisture stability, so it can be seen that the perovskite solar cell according to the present application has excellent photoelectric conversion efficiency.

[Experimental Example 2] Efficiency of perovskite solar cells

A current density graph for a given voltage was obtained by driving the perovskite solar cells prepared according to Examples and Comparative Examples, respectively.

13 is a current-voltage curve comparison result of perovskite solar cells according to Examples, Comparative Examples 1, and 2 of the present application.

Specifically, (a) of Figure 13 is a current density (Current Density) graph with respect to voltage for each of the perovskite solar cells prepared according to Examples, Comparative Example 1, and Comparative Example 2, (b) is a short-circuit current (J _sc ), an open-circuit voltage (V _oc ), a charge factor (Fill factor, FF) and power conversion efficiency {power conversion efficiency, PCE, η} are compared and shown.

14 is a box chart of photoelectric parameters of perovskite solar cells according to Examples and Comparative Examples of the present application.

13 and 14 , the perovskite solar cell of Example (Au/Spiro-OMeTAD/OLA/Pev/TiO ₂ /FTO) is the perovskite solar cell of Comparative Example 1 (Au/Spiro-OMeTAD/ Pev/TiO ₂ /FTO), the V _oc and FF characteristics are greatly improved, and it can be seen that high-efficiency solar cell characteristics are exhibited.

In addition, the perovskite solar cell of Example (Au/Spiro-OMeTAD/OLA/Pev/TiO ₂ /FTO) is the perovskite solar cell of Comparative Example 2 (Au/Spiro-OMeTAD/OLA'/Pev/TiO) ₂ /FTO), the V _oc and FF characteristics are greatly improved by the vacuum process, and it can be confirmed that high efficiency solar cell characteristics are exhibited. It can be confirmed that the perfect passivation layer (OLA) is formed by the vacuum process in the embodiment, and furthermore, there is a synergistic effect of FF characteristics, and the photoelectric conversion efficiency (PCE) is increased by 1% or more compared to Comparative Example 2.

The foregoing description of the present application is for illustration, and those of ordinary skill in the art to which the present application pertains will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present application is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present application.

100: transparent substrate
200: electron transport layer
300: perovskite light absorption layer
310: defect
320: perovskite material
400: organic monolayer
500: hole transport layer
600: electrode

Claims (15)

delete delete delete delete delete delete delete delete delete delete forming an electron transport layer on a transparent substrate;
forming a perovskite light absorption layer on the electron transport layer;
forming an organic monolayer on the perovskite light absorption layer;
forming a hole transport layer on the organic monolayer; and
forming an electrode on the hole transport layer;
including,
The organic monolayer is to form a bond with the perovskite light absorption layer by self-assembly,
The organic monolayer is to be formed under a pressure of ^{10 -3} torr to 10 ^{-2 torr,}
A hydrophilic group is formed on one surface of the organic monolayer, and a hydrophobic group is formed on the other surface,
A method for manufacturing a perovskite solar cell.
delete delete 12. The method of claim 11,
The organic monolayer is a method selected from the group consisting of spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof. The method for manufacturing a perovskite solar cell, which is formed on the light absorption layer by
12. The method of claim 11,
The perovskite light absorption layer and the hole transport layer are spin coating, bar coating, inkjet printing, nozzle printing, spray coating, slot die coating, gravure printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof. Which is formed by a method selected from the group consisting of, a method of manufacturing a perovskite solar cell.

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