Surface treatment method for perovskite thin film and solar cell manufactured by comprising same

Abstract

The present invention relates to a surface treatment method for a perovskite thin film and, more specifically, to: a surface treatment method for a perovskite thin film, capable of improving durability and efficiency and ensuring light stability by removing surplus ions present in a perovskite thin film; and to a solar cell manufactured by comprising same.

Description

Method for surface treatment of perovskite thin film and solar cell manufactured using the same

[0001] The present invention relates to a method for surface treatment of a perovskite thin film, and more specifically, to a method for surface treatment of a perovskite thin film, which enables improvement of durability and efficiency and securing photostability through a method for removing excess ions present in the perovskite thin film, and to a solar cell manufactured including the same.

[0002] In modern society, various new and renewable energy sources are being developed to address the depletion of conventional fossil fuels and environmental pollution. For these new and renewable energy sources to be commercialized, it is crucial to ensure superior energy efficiency, long-term stability, and large-scale mass production.

[0003] Recently, the development of perovskite solar cells that utilize organic-inorganic perovskite compounds as light absorbers has been actively progressing. Organometallic halides with a perovskite structure, referred to as organic-inorganic perovskite compounds, are substances represented by the chemical formula AMX3, consisting of an organic cation (A), a metal cation (M), and a halogen anion (X).

[0004] These perovskite solar cells are the closest to commercialization among the next-generation solar cells, including dye-sensitized and organic solar cells, and are receiving increasing attention as their efficiency is reported to be approximately 20% (Korean Patent Publication No. 2014-0035284).

[0005] These perovskite solar cells are evaluated as having excellent commercial viability because they exhibit excellent efficiency comparable to silicon solar cells, but also have low material prices and can be produced through low-temperature or low-cost solution processes.

[0006] However, there are still several issues that need to be resolved for the full commercialization of these perovskite solar cell modules, the most important of which is module stability.

[0007] To improve the stability of perovskite solar cell modules, reducing surface defects in the module's constituent layers is crucial. In particular, residual ions within the perovskite thin film can degrade cell performance, so various methods are being developed to remove these ionic defects.

[0008] In the past, a vacuum process was used as a method for removing ion defects in an existing perovskite thin film, or a method was used in which another thin film was coated on the perovskite thin film, a vacuum process was performed, and then the coated thin film was removed again.

[0009] However, these existing methods have drawbacks such as requiring a long time for the vacuum process, requiring an additional solvent treatment process to remove the thin film coated on the perovskite thin film, complicating the process, and causing environmental pollution due to the solvent treatment, making it difficult to apply them to mass production processes.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] (Patent Document 1) Korean Patent Publication No. 10-2014-0035284

[0013] The present invention is intended to solve the above problems, and provides a method for surface treatment of a perovskite thin film, which can secure durability and efficiency improvement and photostability by removing excess ions present in the perovskite thin film, and a solar cell manufactured including the method.

[0014] The above and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

[0015] The above object can be achieved by a method for surface treatment of a perovskite thin film, comprising: a step of forming a perovskite thin film layer; a step of laminating an adhesive film on the thin film layer; a step of heat-treating the laminated adhesive film; and a step of delaminating the adhesive film after completing the heat treatment.

[0016] The step of forming the perovskite thin film layer is characterized by including the steps of: preparing a perovskite solution containing a perovskite compound; spin-coating the perovskite solution; and performing a primary heat treatment after spin-coating.

[0017] The above first heat treatment is characterized by performing heat treatment at 115 to 125°C for 20 to 30 minutes and annealing at 145 to 155°C for 3 to 7 minutes. The heat treatment of the present invention is not limited to a specific method and may be performed using a heat treatment device such as an oven or a hot plate.

[0018] The above adhesive film is characterized in that it is a polymer film on which an adhesive is applied or has a self-adhesive function.

[0019] The above object can be achieved by a perovskite solar cell including a perovskite thin film layer surface-treated by a surface treatment method of a perovskite thin film as a light-absorbing layer.

[0020] The above object can be achieved by a method for manufacturing a perovskite solar cell, comprising: preparing a first electrode layer; forming an electron transport layer on the first electrode layer; forming a perovskite thin film layer on the electron transport layer; performing a surface treatment method of a perovskite thin film according to any one of claims 1 to 5 on the perovskite thin film layer; forming a hole transport layer on the surface-treated perovskite thin film layer; and forming a second electrode layer on the hole transport layer.

[0021] According to the present invention, a surface treatment method for a perovskite thin film layer can effectively remove excess ions and solvents present within the thin film. This significantly reduces surface defects and failure rates in the perovskite thin film layer, thereby improving the durability and efficiency of the device.

[0022] However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0023] FIG. 1 is a diagram schematically illustrating step S30 of a surface treatment method for a perovskite thin film according to one embodiment of the present invention.

[0024] FIG. 2 is a diagram schematically showing steps S31 and S32 of a surface treatment method for a perovskite thin film according to one embodiment of the present invention.

[0025] FIG. 3 is a diagram schematically illustrating step S33 of a surface treatment method for a perovskite thin film according to one embodiment of the present invention.

[0026] Figure 4 is a photograph showing the appearance of the hole transport layer of Example 1 of the present invention after coating according to Experimental Example 2.

[0027] Figure 5 is a photograph showing the appearance of the hole transport layer of Comparative Example 1 of the present invention after coating according to Experimental Example 2.

[0028] Figure 6 is a graph showing the results of measuring the photostability of solar cells of Example 1 and Comparative Example 1 according to Experimental Example 3.

[0029] Figure 7 is a scanning electron microscope (SEM) photograph of a cross-section of a solar cell module of Example 1 and Comparative Example 1 according to Experimental Example 4.

[0030] Figure 8 is a transmission electron microscope (TEM) and scanning transmission electron microscope (STEM) photograph of the cross-section of the solar cell module of Example 1 and Comparative Example 1 according to Experimental Example 4.

[0031] Figure 9 is an image showing the results of component analysis of the solar cell of Comparative Example 1 according to Experimental Example 4.

[0032] Figure 10 is an image showing the results of component analysis of the solar cell of Example 1 according to Experimental Example 4.

[0033] Figure 11 is a graph showing the results of component analysis for the entire area of ​​the solar cells of Example 1 and Comparative Example 1 according to Experimental Example 4.

[0034] Figure 12 is a graph showing the results of component analysis of the Au electrode layer of the solar cells of Example 1 and Comparative Example 1 according to Experimental Example 4.

[0035] Figure 13 is a graph showing the results of component analysis for other layers of the solar cells of Example 1 and Comparative Example 1 according to Experimental Example 4.

[0036] Figures 14 and 15 are graphs showing the voltage-current characteristics of the solar cells of Examples 2 and 3, respectively, according to Experimental Example 5.

[0037] Hereinafter, the present invention will be described in detail with reference to examples and drawings. These examples are provided solely as examples to more specifically illustrate the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples.

[0038] Additionally, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in case of conflict, the description in this specification, including definitions, shall prevail.

[0039] To clearly explain the invention proposed in the drawings, irrelevant parts have been omitted, and similar parts have been designated with similar drawing reference numerals throughout the specification. Furthermore, when a part is said to "include" a component, this does not mean that other components are excluded, but rather that other components may be included, unless otherwise specifically stated. Furthermore, the term "part" described in the specification refers to a single unit or block that performs a specific function.

[0040] The identifiers (1, 2, etc.) for each step are used for convenience of explanation and do not describe the order of each step. Each step may be performed in a different order than stated unless the context clearly indicates a specific order. In other words, each step may be performed in the same order as stated, may be performed substantially simultaneously, or may be performed in the opposite order.

[0041] In the present invention, the perovskite compound, i.e., the organic-inorganic perovskite compound (hereinafter collectively referred to as the perovskite compound), means an organometallic halide having a perovskite structure.

[0042] In the present invention and the present specification, a solar cell means a solar cell containing a perovskite compound as a light absorber.

[0043] Hereinafter, implementation examples and embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention may not be limited to these implementation examples and embodiments and drawings.

[0044] The method for surface treatment of a perovskite thin film of the present invention may include a step of forming a perovskite thin film layer (S30); a step of laminating an adhesive film on the thin film layer (S31); a step of heat-treating the laminated adhesive film (S32); and a step of delaminating the adhesive film after completing the heat treatment (S33).

[0045] The method for surface treatment of the above perovskite thin film is to laminate the adhesive film on the perovskite thin film layer so that impurities such as excess ions or solvents in the perovskite module move into the polymer chain space of the adhesive film, thereby removing excess ions more safely and easily than with a physical method, and furthermore, it can exhibit effects such as improving the performance and durability of the perovskite module.

[0046] Figures 1 to 3 are schematic drawings showing a surface treatment method of a perovskite thin film according to one embodiment of the present invention.

[0047] Referring to Fig. 1, first, a perovskite thin film layer (30) can be formed. The perovskite compound of the perovskite thin film layer (30) may have, for example, a structure represented by the following chemical formula 1, but is not necessarily limited thereto.

[0048] <Chemical Formula 1>

[0049] (FAPbI3) x (MAPbBr3) 1-x

[0050] In chemical formula 1, A is an organic cation, M is a divalent metal ion, and is a real number of 0.10≤X≤0.90.

[0051] The above perovskite thin film layer (30) can be formed in the form of a thin film by a method such as spin-coating a perovskite solution in which the perovskite compound is dissolved in a solvent. The specific method for forming the thin film is not particularly limited and can follow a known technique.

[0052] After the above thin film formation is completed, the first heat treatment can be performed.

[0053] The above first heat treatment may be performed by heat treating the formed perosite thin film layer (30) at, for example, 115 to 125°C for 20 to 30 minutes and annealing at 145 to 155°C for 3 to 7 minutes. For example, the perosite thin film layer (30) may be heat treated at 120°C for 25 minutes and annealed at 150°C for 5 minutes. In addition, the heat treatment of the present invention is not limited to a specific method and may be performed using a heat treatment device such as an oven or a hot plate.

[0054] Referring to FIG. 2, an adhesive film (40) can be laminated on the perovskite thin film layer (30) (S31). In this case, lamination may mean attaching the adhesive film (40) to the perovskite thin film layer (30).

[0055] The above adhesive film (40) may be, for example, a polymer film coated with an adhesive. The adhesive may have an adhesive strength of, for example, 5 to 50 N / 100 mm, specifically 5 to 30 N / 100 mm, according to ASTM D3330 (adhesive = standard stainless steel panel).

[0056] The adhesive may be, for example, an acrylic adhesive, a rubber adhesive, or a silicone adhesive.

[0057] The acrylic adhesive may include, for example, a (meth)acrylic acid alkyl ester as a monomer. The rubber adhesive may include, for example, an adhesive material based on styrene-butadiene-styrene (SBS) rubber. The silicone adhesive may include, for example, an adhesive material based on polydimethylsiloxane and polysiloxane rubber, but the adhesive components are not limited thereto. For example, the adhesive may use a silicone adhesive.

[0058] Additionally, the adhesive film of the present invention may be a polymer film having a self-adhesive function, in which case a separate application of an adhesive is not required. For example, a polypropylene film having a self-adhesive function may be used.

[0059] The polymer film is a film on which the adhesive is applied on at least one surface or has a self-adhesive function, and may be, for example, polyester, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyurethane (PU), polyalkylene (polypropylene (PP), polyethylene (PE), polystyrene (PS), polyacrylate), polyimide (PI), polyamide (PA), polyetherimide (PEI), polytetrafluoroethylene (PTFE), polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), triacetyl cellulose (TAC), polyether sulfone (PES), etc. As an example, the polymer film may be made of polyethylene terephthalate (PET).

[0060] However, the examples of the polymer films above are not limited thereto.

[0061] The above polymer film exhibits the effect of removing excess ions by allowing impurity ions to penetrate into the spaces within the polymer chains, and since it depends on the physical properties of the polymer rather than the chemical properties, any type of polymer film can be applied as long as there is space between the polymer chains.

[0062] The pressure applied to bond the adhesive film (40) is sufficient as long as it is stable enough to attach the adhesive film (40) to the surface of the perovskite thin film layer (30) without causing physical damage to the perovskite thin film layer (30).

[0063] For example, when the adhesive film (40) is laminated, 0.5 to 15 kgf / cm 2 The pressure may be applied to, but is not limited to,

[0064] The pressure applied when bonding the above adhesive film (40) may be applied using any means that can uniformly apply pressure to the entire area, taking into consideration the size or area of ​​the perovskite thin film layer (30) to be manufactured.

[0065] For example, pressure may be applied through a member such as a roller or a flat plate. However, a separate member is not necessarily required when applying pressure, and in case of small size, pressure may be applied by simply pressing the adhesive film (40) with a part of the human body, such as a finger, without using a separate member.

[0066] Next, the laminated adhesive film (40) can be heat-treated (S32). The heat treatment may be a secondary heat treatment performed on the perovskite thin film layer (30) to which the adhesive film (40) is laminated.

[0067] The above secondary heat treatment can cause all excess ions present in the perovskite thin film layer (30) to move into the space between the polymer chains of the adhesive film (40).

[0068] The above secondary heat treatment may be, for example, heat treatment performed at 115 to 125°C (e.g., 120°C) for 20 to 30 minutes (e.g., 25 minutes) and annealing performed at 145 to 155°C (e.g., 150°C) for 3 to 7 minutes (e.g., 5 minutes). Like the primary heat treatment, it is not limited to a specific method and may be performed using a heat treatment device such as an oven or a hot plate.

[0069] The conditions of the secondary heat treatment described above have the effect of maximizing the mobility of excess ions. That is, excess ions that may exist not only in the perovskite thin film layer (30) but also in the first electrode and electron transport layer can all rapidly move into the space between the polymer chains within the adhesive film (40).

[0070] Referring to Fig. 3, the adhesive film (40) that has undergone heat treatment can be delaminated (S33). In this case, delamination may mean detaching (removing) the adhesive film (40) after the heat treatment. During detachment, any excess ions and solvents that have moved into the adhesive film (40) can also be removed.

[0071] In order to facilitate separation when the adhesive film (40) is separated from the perovskite thin film layer (30), a separate member may be used.

[0072] In addition, since the surface of the perovskite thin film layer (30) is physically treated during the above-described deposition, no chemical reaction is formed.

[0073] When detaching (detaching) the adhesive film (40), it is preferable to separate the adhesive film (40) by forming an angle of 90 to 180°, specifically, 120° to 180°, and more specifically, 160° to 180° between the adhesive film (40) and the perovskite thin film layer so that physical surface treatment can be performed uniformly and stably.

[0074] The speed of separating the adhesive film (40) (corresponding to the movement speed of the boundary line described above) may be, for example, 0.01 cm / sec to 5 cm / sec, but is not limited thereto. In practice, the removal speed of the adhesive film (40) does not significantly affect the presence or degree of surface treatment, and any speed that allows the adhesive film (40) to be removed without leaving any unwanted residue is sufficient.

[0075] That is, when the adhesive film (40) is used, impurities adsorbed on the surface of the perovskite thin film layer (30), impurities remaining in the surface area of ​​the film during the manufacturing process of the perovskite compound film, or surface defects are removed together, thereby forming a perovskite thin film layer surface with a more defect-free surface underlayer, and thus the film quality can be improved.

[0076] In addition, the delamination of the adhesive film (40) may be performed at any point before the formation of another component layer positioned on top of the perovskite thin film layer. For example, it is preferable that the delamination of the adhesive film (40) be performed immediately before the formation of another component layer positioned on top of the perovskite thin film layer. In this way, the perovskite thin film layer can also function as a protective film to protect it from contamination or damage.

[0077] The process of lamination-heat treatment-delamination by the above-described S30 to S33, i.e., the method of surface treatment of the perovskite thin film layer (30), can effectively remove all excess ions that may exist not only in the perovskite thin film layer (30), but also in other regions of the solar cell, such as the first electrode and the electron transport layer.

[0078] In addition, compared to the conventional method of coating an ion-removing material and then removing it using a solvent, since it is a method based on the physical properties of the polymer film itself rather than a chemical reaction, there is less concern about the additional generation of other impurities or side reactions, and furthermore, it can contribute to increasing productivity by demonstrating effects such as convenience of the process, shortening of the process time, and reduction of wastewater generation.

[0079] Meanwhile, a description of a perovskite module including a perovskite thin film layer (30) to which the surface treatment method of the perovskite thin film layer (30) is applied is as follows.

[0080] The above perovskite module may be, for example, a perovskite solar cell, but is not limited thereto.

[0081] The perovskite solar cell may include a first electrode (10); an electron transport layer (20) positioned on the first electrode (10); a light absorption layer positioned on the electron transport layer (20) and including a surface-treated perovskite thin film layer (30); a hole transport layer positioned on the light absorption layer; and a second electrode positioned on the hole transport layer.

[0082] At this time, at least one of the first electrode and the second electrode may be a transparent electrode, and the remaining electrode may be a transparent electrode or an opaque electrode (metal electrode).

[0083] The first electrode or the second electrode is not particularly limited as long as it is one commonly used in the art, and if the electrode is a transparent electrode, the transparent electrode may be a transparent conductive electrode that forms an ohmic contact with an adjacent layer (electron transport layer or hole transport layer).

[0084] As a specific example, the transparent electrode may be one or more selected from fluorine doped tin oxide (FTO), indium doped tin oxide (ITO), ZnO, carbon nanotubes, graphene, and composites thereof.

[0085] If the electrode is an opaque electrode, the electrode may include one or more materials selected from, but not limited to, gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and composites thereof.

[0086] At this time, the first electrode or the second electrode may be formed through a deposition process such as physical vapor deposition or chemical vapor deposition, and specifically, may be formed by thermal evaporation, but is not limited thereto.

[0087] In one specific example, the first electrode may be a transparent electrode, and the first electrode may be positioned on a transparent substrate. The transparent substrate may be a rigid substrate (support) or a flexible substrate (support). As an example of the transparent substrate (support), the rigid substrate may be a glass substrate, and the flexible substrate may be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), polypropylene (PP), triacetyl cellulose (TAC), or polyether sulfone (PES), but it is to be understood that the present invention is not limited to the specific material of the substrate.

[0088] The electron transport layer may be inorganic and may include a metal oxide. The electron transport layer may be a flat metal oxide layer, a metal oxide layer having a surface roughness, a composite metal oxide layer in which nanostructures of the same or different metal oxides (including metal oxide particles, nanowires, and / or nanotubes) are formed on the surface of a metal oxide in the form of a thin film, a dense metal oxide layer, or a porous metal oxide layer.

[0089] For example, the electron transport layer may be a laminated film of a metal oxide film (dense film) and a porous (meso-porous) metal oxide film, more specifically, a laminated film of a dense film and a porous film.

[0090] A metal oxide film (dense film) can be formed through a deposition process such as physical or chemical vapor deposition, or by applying and heat treating metal oxide nanoparticles. A porous metal oxide film can include metal oxide particles and have an open porous structure due to the empty spaces between these particles.

[0091] In one example, a porous metal oxide film can be manufactured by applying a slurry containing metal oxide particles on top of a metal oxide film (dense film), and drying and heat-treating the applied slurry layer. The application of the slurry can be performed by one or more methods selected from screen printing, spin coating, bar coating, gravure coating, blade coating, and roll coating.

[0092] The main factors affecting the specific surface area and open pore structure of the porous metal oxide film are the average particle size of the metal oxide particles and the heat treatment temperature. The average particle size of the metal oxide particles may be 5 to 500 nm, and the heat treatment may be performed in air at 200 to 600°C, but is not necessarily limited thereto.

[0093] The thickness of the electron transport layer may be, for example, 50 nm to 10 μm, specifically 50 nm to 5 μm, more specifically 50 nm to 1 μm, and even more specifically 50 to 800 nm, but is not necessarily limited thereto.

[0094] The metal oxide of the electron transport layer may be used without particular limitation as long as it is a metal oxide commonly used for the movement of photoelectrons in solar cells, particularly in the field of perovskite solar cells. Specifically, for example, it may be one or two or more selected from the group consisting of Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Zr oxide, Sr oxide, Yr oxide, La oxide, V oxide, Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, In oxide, and SrTi oxide and composites thereof.

[0095] The thickness of the perovskite thin film layer contained in the light-absorbing layer is not particularly limited, but may be 100 nm to 1 μm, and in a specific example, 200 to 800 nm.

[0096] The light-absorbing layer can be manufactured using a conventional solution-coating method, such as spin coating, in which a perovskite solution containing the above-described perovskite compound dissolved in a solvent is applied and dried. The method for manufacturing the perovskite thin film layer can be performed according to known techniques.

[0097] After manufacturing the perovskite thin film layer, surface treatment of the perovskite thin film layer can be performed by the above-described S30 to S33. Thereafter, a hole transport layer can be formed on the perovskite thin film layer on which the surface treatment has been completed.

[0098] The hole transport layer may be an organic hole transport layer, and the organic hole transport material of the organic hole transport layer may be a single-molecule or high-molecular organic hole transport material.

[0099] Non-limiting examples of single-molecule to small-molecule organic hole transport materials include pentacene, coumarin 6 (3-(2-benzothiazolyl)-7-(diethylamino)coumarin), zinc phthalocyanine (ZnPC), copper phthalocyanine (CuPC), titanium oxide phthalocyanine (TiOPC), Spiro-MeOTAD (2,2',7,7'-tetrakis(N,Np-dimethoxyphenylamino)-9,9'-spirobifluorene), F16CuPC (copper(II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine), SubPc (boron subphthalocyanine chloride), and One or more substances selected from N3(cis-di(thiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)- ruthenium(II)) may be mentioned, but are not limited thereto.

[0100] 고분자 유기 정공전달물질의 비 한정적인 일 예로, P3HT(poly[3-hexylthiophene]), MDMO-PPV(poly[2-methoxy5-(3',7'- dimethyloctyloxyl)]-1,4-phenylene vinylene), MEH-PPV(poly[2-methoxy -5-(2''-ethylhexyloxy)- p-phenylene vinylene]), P3OT(poly(3-octyl thiophene)), POT( poly(octyl thiophene)), P3DT(poly(3-decyl thiophene)), P3DDT(poly(3-dodecyl thiophene), PPV(poly(p-phenylene vinylene)), TFB(poly(9,9'- dioctylfluorene-co-N-(4-butylphenyl)diphenyl amine), Polyaniline, Spiro-MeOTAD ([2,22′,7,77′-tetrkis (N,N-di-p-methoxyphenyl amine)-9,9,9′-spirobi fluorine]), PCPDTBT(Poly[2,1,3-benzothiadiazole- 4,7- diyl[4,4-bis(2-ethylhexyl-4H- cyclopenta [2,1-b:3,4-b']dithiophene-2,6-diyl]], Si-PCPDTBT(poly[(4,4′- bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), PBDTTPD(poly((4,8-diethylhexyloxyl) benzo([1,2-b:4,5-b']dithiophene)-2,6-diyl)-alt-((5- octylthieno[3,4-c]pyrrole-4,6-dione)-1,3-diyl)), PFDTBT(poly[2,7-(9-(2-ethylhexyl)-9-hexyl-fluorene)- alt-5,5-(4', 7,-di-2-thienyl-2',1', 3'-benzothiadiazole)]), PFO-DBT(poly[2,7-.9,9-(dioctyl-fluorene)- alt-5,5-(4',7'-di-2-.thienyl-2', 1', 3'-benzothiadiazole)]), PSiFDTBT(poly[(2,7-dioctylsilafluorene)- 2,7-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5′-diyl]), PSBTBT(poly[(4,4′-bis(2- ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), Examples of materials selected from one or more of PCDTBT (Poly [[9-(1-octylnonyl)-9H-carbazole-2,7-diyl] -2,5-thiophenediyl -2,1,3-benzothiadiazole-4,7- diyl-2,5-thiophenediyl]), PFB (poly(9,9′-dioctylfluorene-co-bis(N,N′-(4,butylphenyl))bis(N,N′- phenyl-1,4-phenylene)diamine), F8BT (poly(9,9′-dioctylfluorene-co-benzothiadiazole), PEDOT (poly(3,4- ethylenedioxythiophene)), PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)), PTAA (poly(triarylamine)), Poly(4-butylphenyl-diphenyl-amine) and copolymers thereof may be mentioned, but are not limited thereto. no.,

[0101] The hole transport layer may, of course, further contain known additives such as tertiary butyl pyridine (TBP), lithium bis(trifluoro methanesulfonyl)imide (LiTFSI), bis(trifluoromethane) sulfonimide (HTFSI), 2,6-lutidine, and Tris(2-(1H-pyrazol-1-yl)pyridine)cobalt(III).

[0102] The thickness of the hole transport layer may be 10 to 500 nm, but is not necessarily limited thereto.

[0103] The hole transport layer can be formed by applying and drying a solution containing an organic hole transport material (hereinafter, referred to as an organic hole transport solution) on the light absorbing layer. The solvent used to form the hole transport layer may be any solvent that dissolves the organic hole transport material and does not chemically react with the perovskite compound and the materials of the electron transport layer.

[0104] For example, the solvent used for forming the hole transport layer may be a nonpolar solvent, and as a practical example, may be one or more selected from toluene, chloroform, chlorobenzene, dichlorobenzene, anisole, xylene, and hydrocarbon solvents having 6 to 14 carbon atoms, but is not limited thereto.

[0105] On the organic hole transport layer, a second electrode, which is a transparent or opaque electrode as described above, can be formed.

[0106] For example, the second electrode may be an opaque electrode (metal electrode), and the second electrode may include one or more materials selected from, but not limited to, gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and composites thereof.

[0107] At this time, the second electrode may be formed through a deposition process such as physical vapor deposition or chemical vapor deposition, and specifically, may be formed by thermal evaporation, but is not limited thereto.

[0108] In addition to the composition and manufacturing method of the perovskite solar cell described above, known composition layers and manufacturing processes commonly used in the field may be further included without limitation.

[0109] Hereinafter, the composition and resulting effects of the present invention will be described in more detail through specific examples and comparative examples. However, these examples are intended to more specifically illustrate the present invention, and the scope of the present invention is not limited to these examples.

[0110] [Example 1: Fabrication of a solar cell including a perovskite thin film layer subjected to surface treatment]

[0111] 1-1. Drying treatment of the substrate

[0112] After preparing the PET / ITO film substrate, it was dried in an oven at 120°C for 30 minutes. The above process is to prevent shrinkage of the substrate in subsequent processes.

[0113] 1-2. Plasma treatment of the substrate

[0114] The dried substrate was plasma treated using a plasma treatment device. The above process is to evenly coat the subsequent SnO2 layer.

[0115] 1-3. Fabrication of SnO2 layer

[0116] A SnO2 thin film was fabricated by applying a dispersion of tin oxide nanoparticles (SnO2 nanoparticles) dispersed in deionized water at a concentration of 15 wt% by a shearing method on a plasma-treated substrate.

[0117] 1-4. Heat treatment process

[0118] The substrate on which the SnO2 thin film was formed was dried at 150°C for 30 minutes using a hot plate.

[0119] 1-5. Plasma treatment of the substrate

[0120] The same process as 1-2 above was carried out.

[0121] The substrate on which the SnO2 thin film was formed was plasma treated using a plasma treatment device.

[0122] 1-6. Preparation of perovskite solution

[0123] (FAPbI3)x(MAPbBr3) in a mixed solvent of 0.8 ml of DMF and 0.1 ml of DMSO 1-x A perovskite solution was prepared by adding 1 mol based on the amount of 1% and adding MACl so that 0.0004 mol based on 1 mol.

[0124] 1-7. Fabrication of perovskite thin film layers

[0125] The solution prepared in the above 1-6. was coated on the SnO2 layer by the shearing method, and then spin-coated at 2,000 rpm for 30 seconds. During spin-coating, 100 ml of diethyl ether was poured 17 seconds after the start of coating, and after spin-coating was completed, the perovskite thin film layer (light-absorbing layer) was manufactured by annealing in a 120°C oven for 25 minutes and on a 150°C hot plate for 5 minutes.

[0126] 1-8. Lamination-Heat Treatment-Delamination (LHDL) Process

[0127] An adhesive film (3M PET film coated with silicone adhesive) was laminated at a speed of 1 mm / s onto the manufactured perovskite thin film layer, and then annealed in a 120°C oven for 25 minutes and on a 150°C hot plate for 5 minutes. The laminated adhesive film was then delaminated.

[0128] 1-9. Formation of an organic hole transport layer (PTAA)

[0129] An organic hole transport layer was formed by shearing coating an organic hole transport solution on a perovskite thin film layer on which the LHDL process was completed. The organic hole transport solution was prepared by adding 10 mg / ml of PTAA (poly(triarylamine)) to toluene and mixing TFSI (bis(trifluoromethane)sulfonamide) and octylamine.

[0130] 1-10. Fabrication of electrode (Au) layer

[0131] Afterwards, a solar cell was manufactured by forming an Au electrode (100 nm) on the organic hole transport layer using a thermal evaporator.

[0132] [Comparative Example 1]

[0133] Except for the contents described below, a solar cell was manufactured by performing the same manufacturing method as in Example 1 described above.

[0134] Process 1-8 of Example 1 was not performed.

[0135] <Experimental Example 1: Battery Performance Evaluation>

[0136] A performance evaluation was conducted on each solar cell manufactured according to Example 1 and Comparative Example 1. At this time, a comparison was also made between a test group in which the heat treatment conditions of steps 1-7 of Example 1 and Comparative Example 1 were performed as is, and a comparison group in which the heat treatment conditions were different.

[0137] The performance evaluation items are open circuit voltage (Voc) (V), short circuit current (Isc) (mA), and short circuit current density (JSC) (mA / cm 2 ), fill factor (FF) (%) and photoelectric conversion efficiency (PCE) (%) were measured according to known techniques, and the results are shown in Table 1 below.

[0138]

[0139] Referring to Table 1, it was confirmed that the solar cell of Example 1 had improved battery performance in all items compared to Comparative Example 1. In addition, it was confirmed that the battery performance of the experimental group was improved overall compared to the comparative group.

[0140] <Experimental Example 2: Coating Evaluation>

[0141] When performing process 1-9 (hole transport layer formation) on the solar cells according to Example 1 and Comparative Example 1, the coating properties were visually evaluated in terms of appearance. The evaluation results are shown in Figs. 4 and 5, respectively.

[0142] Referring to FIGS. 4 and 5 together, it was confirmed that Example 1 had significantly reduced impurities such as white dots in the coating layer compared to Comparative Example 1. Accordingly, it was found that in the case of Example 1, the quality of the appearance when coating the hole transport layer (PTAA) could be improved by performing process 1-8, i.e., surface treatment, to remove residual solvent or ions on the thin film surface.

[0143] <Experimental Example 3: Photostability Evaluation>

[0144] For the solar cells manufactured according to Example 1 and Comparative Example 1, photostability was evaluated according to known techniques. The evaluation results are shown in Fig. 6.

[0145] Referring to Fig. 6, when evaluating the photostability at 10,000 lx, the photostability efficiency was measured to be 93% for Example 1 and 86% for Comparative Example 1, respectively, compared to the initial efficiency after approximately 150 hours. In particular, the initial efficiency of Example 1 was stably maintained without any drop.

[0146] <Experimental Example 4: Cross-section and component analysis>

[0147] Cross-sectional analysis

[0148] Cross-sections of the perovskite solar cell modules manufactured according to Example 1 and Comparative Example 1 were photographed using an electron microscope and subjected to cross-sectional analysis. The results are shown in Figs. 7 and 8.

[0149] Referring to Figure 7, it was confirmed that the bright portion of the perovskite thin film layer in Example 1 was significantly reduced compared to Comparative Example 1.

[0150] Referring to Fig. 8, in the case of the TEM cross-sectional photograph, it was confirmed that the bright part of the perovskite thin film layer of Example 1 was significantly reduced compared to Comparative Example 1, and in the case of the STEM cross-sectional photograph, the opposite was observed. That is, in the case of Example 1, it was confirmed that the excess ions of the thin film layer were removed through the surface treatment process.

[0151] Ingredient Analysis

[0152] Component analysis (Atomic ratio (%)) was performed according to known techniques on perovskite solar cell modules manufactured according to Example 1 and Comparative Example 1. Component analysis was performed on the entire area, the second electrode layer (Au layer), and other areas of the perovskite solar cell, respectively, and the analysis results are shown in Figures 9 to 13, respectively.

[0153] Referring to FIGS. 9 to 13, a significant decrease in In, Sn, I, and Pb ions was confirmed in Example 1 compared to Comparative Example 1. In particular, when compared in the Au layer, it was confirmed that Example 1 showed a large difference in the content of I, Sn, and In compared to Comparative Example 1.

[0154] [Example 2: Fabrication of a solar cell including a perovskite thin film layer subjected to surface treatment]

[0155] Except for the details described below, a solar cell was manufactured by performing the same manufacturing method as in Example 1 described above:

[0156] In process 1-8 of Example 1, a self-adhesive polypropylene (PP) film from 3M was used as the adhesive film instead of the PET film.

[0157] [Example 3: Fabrication of a solar cell including a perovskite thin film layer subjected to surface treatment]

[0158] Except for the details described below, a solar cell was manufactured by performing the same manufacturing method as in Example 1 described above:

[0159] In process 1-8 of Example 1, a polyacrylate film from 3M coated with a silicone adhesive was used instead of the PET film as the adhesive film.

[0160] <Experimental Example 5: Battery Performance Evaluation>

[0161] Performance evaluation was conducted on each solar cell manufactured according to Examples 2 and 3. The performance evaluation items included open circuit voltage (Voc) (V), short circuit current (Isc) (mA), and short circuit current density (JSC) (mA / cm 2 ), fill factor (FF) (%) and photoelectric conversion efficiency (PCE) (%) were measured according to known techniques, and the results are shown in Table 2 below.

[0162]

[0163] Referring to Table 2, it was confirmed that the solar cells of Examples 2 and 3 had improved cell performance in all items compared to Comparative Example 1. In addition, Examples 2 and 3 demonstrated that the effects of the present invention can be achieved for various types of polymer films having polymer chains.

[0164] Also, referring to the voltage-current curves of FIGS. 14 and 15, it can be confirmed that when LHDL is applied (Examples 2 and 3), compared to when LHDL is not applied, the impurities that were hindering electron movement inside the solar cell are removed regardless of the type of polymer film, so that the leakage current is reduced and the resistance is reduced, thereby improving the cell performance.

[0165] Although this specification describes only a few examples among various embodiments performed by the inventors of the present invention, the technical idea of ​​the present invention is not limited or restricted thereto, and can be modified and implemented in various ways by those skilled in the art.

Claims

1. Step of forming a perovskite thin film layer; A step of laminating an adhesive film on the above thin film layer; A step of heat treating the laminated adhesive film; and A method for surface treatment of a perovskite thin film, comprising a step of delaminating an adhesive film that has undergone heat treatment.

2. In paragraph 1, The step of forming the perovskite thin film layer is: A step of preparing a perovskite solution containing a perovskite compound; A step of forming a thin film on a substrate using the perovskite solution; and A method for surface treatment of a perovskite thin film, characterized in that it comprises a step of performing a first heat treatment after forming a thin film.

3. In paragraph 2, A method for surface treatment of a perovskite thin film, characterized in that the first heat treatment is performed at 115 to 125°C for 20 to 30 minutes and annealing is performed at 145 to 155°C for 3 to 7 minutes.

4. In paragraph 1, A method for surface treatment of a perovskite thin film, characterized in that the adhesive film is a polymer film coated with an adhesive or a self-adhesive polymer film having adhesive performance.

5. In paragraph 1, A method for surface treatment of a perovskite thin film, characterized in that the above heat treatment is performed at 115 to 125°C for 20 to 30 minutes and annealing is performed at 145 to 155°C for 3 to 7 minutes.

6. A perovskite solar cell comprising a perovskite thin film layer surface-treated by a surface treatment method of a perovskite thin film according to any one of claims 1 to 5 as a light-absorbing layer.

7. Step of preparing the first electrode layer; A step of forming an electron transport layer on the first electrode layer; A step of forming a perovskite thin film layer on the electron transport layer; A step of performing a surface treatment method of a perovskite thin film according to any one of claims 1 to 5 on the perovskite thin film layer; A step of forming a hole transport layer on a surface-treated perovskite thin film layer; and A method for manufacturing a perovskite solar cell, comprising: forming a second electrode layer on the hole transport layer.

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