KR20180127263A - Preparation for method of perovskite photoactive layer and perovskite solar cells comprising the perovskite photoactive layer thereby - Google Patents

Abstract

According to the present invention, disclosed are a manufacturing method of a perovskite photoactive layer which is dense and controls a crystalline, and a perovskite solar cell including a perovskite photoactive layer manufactured thereby. According to an embodiment of the present invention, the manufacturing method of a perovskite photoactive layer comprises the following steps of: coating a perovskite precursor solution on a substrate and forming a perovskite precursor film; applying pressure to the perovskite precursor film; and applying heat to the pressed perovskite precursor film.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perovskite photoactive layer, a perovskite photoactive layer, a perovskite photoactive layer, and a perovskite photoactive layer. The perovskite photoactive layer includes a perovskite photoactive layer,

The present invention relates to a process for producing a perovskite photoactive layer and a perovskite solar cell comprising the perovskite photoactive layer thus produced.

Research on renewable and clean alternative energy sources such as solar energy, wind power, and hydro power is actively being conducted to solve the global environmental problems caused by depletion of fossil energy and its use. Among these, there is a great interest in solar cells that change electric energy directly from sunlight. Here, a solar cell refers to a cell that generates a current-voltage by utilizing a photovoltaic effect that absorbs light energy from sunlight to generate electrons and holes.

Currently, np diode-type silicon (Si) single crystal based solar cells with a photoelectric conversion efficiency of more than 20% can be manufactured and used in actual solar power generation. Compound semiconductors such as gallium arsenide (GaAs) There is also solar cell using.

However, since such an inorganic semiconductor-based solar cell requires a highly refined material for high efficiency, a large amount of energy is consumed for refining the raw material, and expensive process equipment is required in the process of making single crystal or thin film using raw material And the manufacturing cost of the solar cell can not be lowered, which has been a hindrance to a large-scale utilization.

Accordingly, in order to manufacture a solar cell at a low cost, it is necessary to drastically reduce the cost of a material or a manufacturing process used as a core of the solar cell. As an alternative to an inorganic semiconductor-based solar cell, Type solar cells and organic solar cells have been actively studied.

However, the photoelectric conversion efficiency of the organic solar cell using the conductive polymer remains at 8% (Advanced Materials, 23 (2011), 4636). In the case of the dye-sensitized solar cell, the photoelectric conversion efficiency (Science 334, (2011) 629) at the maximum of 12% to 13%, and is still as low as 7% to 8% when the solid type hollow conductor is used.

The organic / inorganic hybrid solar cell, which combines inorganic semiconductor nanoparticles and a hole conductive polymer with a dye-sensitized solar cell structure, is still showing about 6% efficiency (NanoLetters, 11 (2011) 4789). Accordingly, there is an urgent need to develop a solar cell capable of having a sufficiently high efficiency to replace a conventional silicon single crystal based solar cell.

Recently, perovskite (solar cell) solar cells are being developed, and processes are being optimized for high efficiency.

The perovskite type photoactive layer (light absorbing layer) can be divided into two types. First, a first precursor (PbI ₂ ) and a second precursor (Methylammonium iodide, CH ₃ NH ₃ I) (MAPbI ₃ ). In the second method, a single layer is formed of a first precursor, which is then immersed in a second precursor solution to form a perovskite photoactive layer To form a perovskite photoactive layer.

In the first method, the perovskite photoactive layer prepared by mixing and coating both the first precursor and the second precursor is not only difficult to obtain a dense thin film, but also has difficulty in controlling the morphology.

When the perovskite photoactive layer is formed by immersing the first precursor in the second precursor solution after the first precursor is formed by the second method, crystal growth occurs first in the upper layer contacting the solution due to the nature of the solution deposition method There is a possibility that the second precursor solution is less likely to penetrate to the lower side and the first precursor layer remaining unconverted at the lower side is inevitably formed.

Korean Registered Patent No. 10-1540311 (Jul. 23, 2015), "Photocrystalline Photocrystalline Photovoltaic Cells and Method for Producing the Same"

An embodiment of the present invention seeks to provide a method for producing a dense, crystalline controlled perovskite photoactive layer.

In addition, embodiments of the present invention provide a perovskite solar cell having excellent photoelectric conversion efficiency and a method of manufacturing the same.

A method of manufacturing a perovskite photoactive layer according to an embodiment of the present invention includes: forming a perovskite precursor film by coating a perovskite precursor solution on a substrate; Applying pressure to the perovskite precursor film; And applying heat to the pressurized perovskite precursor film.

The step of applying the pressure may be to apply pressure to the nanoimprinting method.

The step of applying the pressure may be to apply a pressure of 1.0 kgf / cm ² to 2.0 kgf / cm ² for 3 seconds to 15 seconds.

The step of applying the pressure may be performed at a temperature of 60 ° C to 120 ° C.

The step of applying the heat may be performed at a temperature of 60 ° C to 120 ° C for 1 minute to 30 minutes.

The coating may be performed by any one method selected from the group consisting of spin coating, dip coating and spray coating.

A perovskite solar cell according to an embodiment of the present invention includes a substrate; A first electrode formed on the substrate; A hole transport layer formed on the first electrode; A perovskite photoactive layer formed on the hole transport layer and manufactured by the method according to the embodiment of the present invention; An electron transport layer formed on the perovskite photoactive layer; And a second electrode formed on the electron transporting layer.

The thickness of the perovskite photoactive layer may be 100 nm to 1000 nm.

The method of manufacturing a perovskite photoactive layer according to an embodiment of the present invention is characterized in that the perovskite photoactive layer is smoothly crystallized by applying pressure to the perovskite precursor film for forming the perovskite photoactive layer, it is possible to manufacture a perovskite photoactive layer free from pinpoints, dense, and excellent in mopology and crystallinity.

In addition, the perovskite solar cell according to the embodiment of the present invention can exhibit excellent photoelectric conversion efficiency by including the perovskite photoactive layer manufactured according to the embodiment of the present invention.

1 is a flow chart of a method for manufacturing a perovskite photoactive layer according to an embodiment of the present invention.
2 shows a structure of a perovskite solar cell according to an embodiment of the present invention.
3 is an SEM image of the perovskite photoactive layer prepared in Example 1. Fig.
4 is an SEM image of the perovskite photoactive layer prepared in Comparative Example 1. FIG.
5 is a graph of a current-voltage of the perovskite solar cell manufactured in Example 2 and Comparative Example 2. FIG.
6 is a graph of external quantum efficiency (EQE) of the perovskite solar cell manufactured in Example 2 and Comparative Example 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to limit or limit the invention.

The terms " comprises "and / or" comprising ", as used herein, mean that a component, step, operation and / And does not exclude the presence or addition thereof.

As used herein, the terms "embodiment," "example," "side," "example," etc. are intended to be inclusive and mean that any aspect or design described should be construed as being preferred or advantageous over other aspects or designs. It is not.

As used herein, the term "or" refers to an inclusive logical OR rather than an exclusive OR. That is, unless expressly stated otherwise or clear from the context, the expression 'x uses a or b' means any of the natural inclusive permutations.

As used herein, "a" or "an" shall be interpreted generally to mean "one or more ", unless the context clearly dictates otherwise.

It will also be appreciated that where a portion of a film, layer, region, configuration request, etc. is referred to herein as being "on" or "on" another portion, , And a case where a component or the like is interposed.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, a method of manufacturing a perovskite photoactive layer according to an embodiment of the present invention will be described in detail.

1 is a flow chart of a method for manufacturing a perovskite photoactive layer according to an embodiment of the present invention.

Referring to FIG. 1, a method for manufacturing a perovskite photoactive layer according to an embodiment of the present invention includes forming a perovskite precursor film by coating a perovskite precursor solution on a substrate (S110) Applying a pressure to the lobbicular precursor membrane (S120), and applying heat to the pressurized perovskite precursor membrane (S130).

Hereinafter, a method of manufacturing the perovskite photoactive layer according to an embodiment of the present invention will be described in detail for each step.

Step S110 is a step of forming a perovskite precursor film by coating a perovskite precursor solution on the substrate. Specifically, step S110 is to coat a perovskite precursor solution on the substrate to form a single layer of perovskite precursor film.

The substrate is for forming a perovskite precursor film, and the substrate may be an inorganic substrate or an organic substrate.

Inorganic substrate from Si, SiO _2, Ge, GaN, AlN, GaP, InP, GaAs, SiC, Al ₂ O _3, LiAlO _3, MgO, glass, quartz, sapphire, graphite, graphene, and the group consisting of a combination of But are not limited to, those selected.

The organic substrate may be formed of a material selected from the group consisting of polyimide (PI), polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate , Polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polycarbonate (PC), cellulose triacetate (CTA), and cellulose acetate pro But are not limited to, cellulose acetate propionate (CAP).

The perovskite precursor solution is for forming a perovskite precursor film and finally forming a perovskite photoactive layer. The perovskite precursor solution may include a perovskite precursor solution and a solvent.

The perovskite compound is a compound that forms a perovskite structure. The perovskite compound is not limited to the compound that forms the perovskite structure generally used.

The perovskite compound can be represented by the formula of ABX _3. For example, in the above formula, A represents a C1-C20 alkyl group, a monovalent metal (for example, Li, Na, Cs, Rb, Ammonium ion, B may be a divalent metal ion, and X may be a halogen ion.

The perovskite compound used in the present invention may be any one selected from the group consisting of AMX ₃ , A ₂ MX ₆ , A ₃ M ₂ X ₉ , and A ₂ MM'X ₆ , a is CS ^+, C _n H2 _{n + 1} NH ₃ ⁺ (n is an integer of 1 to ^{_{9), NH 4 +, HC}} (NH 2) 2 +, CS +, NF 4 +, NCl 4 +, PF 4 + , PCl ₄ ⁺ , CH ₃ PH ₃ ⁺ , CH ₃ ASH ₃ ⁺ , CH ₃ SbH ₃ ⁺ , PH ₄ ⁺ , ASH ₄ ⁺ , SbH ₄ ⁺ , and combinations thereof. Lt; / RTI > cation,

M, and M 'are Mg, Cu, Mo, Ba, Si, Zn, Tc, Hf, Ca, Ga, Ru, Ta, Sc, Ge, Rh, W, Ti, Pb, Re, Cr, A divalent metal containing at least one selected from the group consisting of Al, Os, Mn, Sr, Cd, Ir, Fe, Y, In, Pt, Co, Zr, Sn, Au, Ni, Nb, Te, Trivalent, tetravalent metal, non-metal cation,

X is a halogen anion comprising any one selected from the group consisting of F-, Cl-, Br-, I-, and combinations thereof.

However, M and M 'in the above formula are different from each other.

The solvent is used for dissolving or dispersing the perovskite compound. The solvent is selected from the group consisting of dimethylformamide (DMF), dimethylsulfoxide (DMSO), g-butylolactone (GBL), N-methyl- NMP), 2-methoxyethanol and the like can be used.

The coating is a method for forming a perovskite precursor film, and the coating can be performed by wet coating such as spin coating, dip coating, spray coating and the like .

When the spin coating method is used as the coating method, the spin coating can be carried out at a rotation speed of 500 rpm to 10,000 rpm, preferably at a rotation speed of 1,500 rpm to 8,000 rpm, more preferably at 2,500 rpm to 7,000 rpm And may be performed for 1 second to 120 seconds, preferably 5 seconds to 60 seconds, but is not limited thereto.

The perovskite precursor film is formed by coating a perovskite precursor solution, and the perovskite precursor film is formed as a single layer.

When the perovskite precursor film is formed into a single layer, the process time can be greatly shortened and a uniform perovskite photoactive layer having a very small degree of roughness can be manufactured. Further, by forming the perovskite precursor film into a single layer, it is possible to make the perovskite an intermediate film which can be mechanically post-processed, so that it is easy to apply pressure.

Next, step S120 is a step of applying pressure to the perovskite precursor film formed in step S110. Specifically, in step S120, the perovskite precursor film is pressure-applied (pressed) to the monovalent perovskite precursor film so as to crystallize the perovskite precursor film so as to have a pin-hole-free and dense structure.

More specifically, when the perovskite precursor film is pressed in step S120, the crystallinity is greatly improved, and a crystal structure having a preferred orientation in a specific direction is formed. Further, due to the pressure of the perovskite precursor film, the perovskite crystal is obtained which shows a phenomenon in which the crystal grain size increases and the morphology becomes dense, the grain boundary angle decreases, and the photoactive layer having few defects is reduced There is a number.

In step S120, the pressing may use a nano imprinting method.

The nanoimprinting method refers to a method capable of forming a nano pattern by imprinting with a mold having a nanostructure formed therein, and a thermal imprint process, a UV imprint process, or the like can be used.

In the nanoimprinting, various patterns such as nano dots, nano meshes, nanorods, and nano holes can be used. By controlling the height of the nano patterns, the distance between patterns, and the size of the pattern, the perovskite photoactive layer The crystallinity and optical properties of the film can be controlled.

In step S120, the pressing may be carried out in a 0.5 pressure kgf / cm ² to 5.0 kgf / cm ² for 1 second to 15 seconds, preferably 1.0 kgf / cm ² to 2.0 kgf / cm for 3 seconds to 15 seconds ^{2. &} Lt; / RTI >

If the pressurization is performed outside the above-described time and pressure range, the durability of the perovskite photoactive layer may deteriorate. In particular, when the pressure is increased, the substrate supporting the perovskite photoactive layer may be broken, and the perovskite photoactive layer itself may be decomposed. When the pressing time is less than 1 second, there is a problem that the crystal growth is not properly performed and the grain size is small. When the pressing time exceeds 15 seconds, the perovskite photoactive layer is disassembled. Further, when the pressing time is longer than 15 seconds and the pressure is greatly increased, the photoactive layer of the perovskite may be decomposed or the morphology of the perovskite photoactive layer may be irregular, Should be.

Step S120 may apply heat to the perovskite precursor film formed in step S110 at the same time as applying pressure. That is, step S120 can pressurize and heat (heat-treat) the perovskite precursor film.

In step S120, when heat treatment is performed concurrently with the pressurization, the pressurization and the heat treatment can be performed at a temperature of 60 占 폚 to 120 占 폚, and preferably at a temperature of 100 占 폚.

When the pressurization and the heat treatment are carried out in the above-mentioned temperature range, if the heat treatment is carried out at a temperature lower than 60 ° C, the crystallization degree by pressurization may be affected. If it exceeds 120 ° C, the mold may be damaged, The decomposition of the stratum may occur rapidly.

Finally, step S130 is a step of applying heat to the pressurized perovskite precursor film in step S120. Specifically, in step S130, the perovskite precursor film is pressurized (heat-treated) in step S120 to stabilize the perovskite photoactive layer.

When more specifically, to be in step S130 perovskite precursor film is heat-treated, Fe lobe case be a sky agent precursor film is heat-treated, becomes the solvent is removed, the perovskite crystal due to binding of PbI2 with CH ₃ NH ₃ I Can be obtained.

In step S130, the heat treatment may be performed at a temperature of 60 占 폚 to 120 占 폚 for 1 minute to 60 minutes, and preferably at a temperature of 100 占 폚 for 5 minutes to 20 minutes.

When the heat treatment is not performed in the above-mentioned time and temperature range, that is, when the heat treatment is performed at less than 60 ° C, the crystallization time and the crystallinity of the photoactive layer may affect the morphology. If the heat treatment is carried out for a long time, the perovskite layer can be decomposed.

According to the embodiment, when the heat treatment is simultaneously performed with the perovskite precursor in step S120, the heat treatment in step S120 may be a primary heat treatment, and the heat treatment in step S130 may be a secondary (additional) heat treatment .

The perovskite photoactive layer produced by the process for producing a perovskite photoactive layer according to an embodiment of the present invention has pinhole-free, dense, and excellent morphology.

In particular, the perovskite photoactive layer according to the embodiment of the present invention is greatly improved in crystallinity and has a crystal structure having a preferred orientation in a specific direction. In addition, perovskite crystals forming a photoactive layer with fewer bonds can be obtained, showing a phenomenon in which the morphology becomes dense and the crystal grain boundary angle decreases as the crystal size increases. Further, in the case of the pressing method using nano-points, a uniform pressure is applied to the perovskite photoactive layer over the entire surface, and a perovskite photoactive layer having few defects is obtained. Further, in the case of the pressing method using nano dots as in the present invention, uniform pressure is applied to the perovskite photoactive layer over the entire surface, and a perovskite photoactive layer having few defects is obtained.

The perovskite photoactive layer produced by the perovskite photoactive layer manufacturing method according to an embodiment of the present invention may have a thickness of 100 nm to 1000 nm, preferably 300 nm to 500 nm Lt; / RTI > If the perovskite photoactive layer has a thickness of less than 100 nm, it may cause a problem of low photocurrent due to light absorption of the photoactive layer, and when the thickness exceeds 1000 nm, hole-electron recombination occurs rapidly The device efficiency can be greatly reduced.

Hereinafter, a perovskite solar cell according to an embodiment of the present invention and a method of manufacturing the same will be described in detail.

2 shows a structure of a perovskite solar cell according to an embodiment of the present invention.

Referring to FIG. 2, a perovskite solar cell according to an embodiment of the present invention includes a substrate 110, a first electrode 120 formed on the substrate 110, a first electrode 120 formed on the first electrode 120, A perovskite photoactive layer 140 formed on the hole transporting layer 130 and a perovskite photoactive layer according to an embodiment of the present invention, An electron transport layer 150 formed on the first electrode layer 140 and a second electrode 160 formed on the electron transport layer 150.

The substrate 110 is a base substrate on which a perovskite solar cell is formed, and the substrate may be an inorganic substrate or an organic substrate.

Inorganic substrate from Si, SiO _2, Ge, GaN, AlN, GaP, InP, GaAs, SiC, Al ₂ O _3, LiAlO _3, MgO, glass, quartz, sapphire, graphite, graphene, and the group consisting of a combination of But are not limited to, those selected.

The organic substrate may be selected from the group consisting of polyimide (PI), polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate But are not limited to, those selected from the group consisting of sulfide (PPS), polyarylate, polycarbonate (PC), cellulose triacetate (CTA) and cellulose acetate propionate (CAP).

A first electrode (120) is formed on the substrate (110). The first electrode 120 may be an anode and is generally used in the field of solar cells. Examples of the first electrode 120 include transparent indium tin oxide (ITO), indium zinc oxide (IZO), fluorinated tin oxide (FTO), tin oxide , Metal oxides such as zinc oxide and zinc aluminum oxide, metal nitrides such as titanium nitride, and polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, poly (3-methylthiophene), polyphenylene sulfide Of a conductive polymer may be used.

A hole transport layer 130 is formed on the first electrode 120. The hole transport layer 130 is formed by applying a hole transporting material. The hole transporting material may include PEDOT: PSS (poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate)), polyaniline, (Phenyl) acetylene, poly (t-butyl) diphenylacetylene, poly (trifluoromethyl) diphenylacetylene, Cu-PC (cooper- phthalocyanine) poly (bistrifluoromethyl) acetylene, (Phenyl) acetylene, poly (trimethylsilyl) diphenylacetylene, poly (carbazole) diphenylacetylene, polydiacetylene, polyphenylacetylene, polypyridine acetylene, polymethoxyphenylacetylene, polymethylphenylacetylene, May be selected from the group consisting of phenylacetylene, polynitrophenylacetylene, poly (trifluoromethyl) phenylacetylene and poly (trimethylsilyl) phenylacetylene, or mixtures thereof, One that does not. The hole transport layer 130 may be formed by spin-coating a hole transport material.

The perovskite photoactive layer 140 is formed on the hole transport layer 130.

The perovskite photoactive layer 140 is manufactured by the method of manufacturing the perovskite photoactive layer according to the embodiment of the present invention, and a repeated description thereof will be omitted.

An electron transport layer 150 is formed on the perovskite photoactive layer 140.

The electron transport layer 150 is a material used in the field of the solar cell and includes, for example, fullerene (C60, C70, C74, C76, C78, C82, C95) and a fullerene derivative containing the same, polybenzimidazole (PBI), carbon nanorods, carbon nanotubes, zinc sulfide (ZnS), 3,4,9,10-perylene tetracarboxylic bisbenzimidazole (PTCBI), materials containing perylene diimide ), Corannulene, Truxenone, Subphthalocyanines (SubPcs) compounds, metal oxides, and derivatives thereof.

The second electrode 160 is formed on the electron transporting layer 150.

The second electrode 160 may be a negative electrode. The second electrode 160 receives the charges generated in the perovskite photoactive layer 140 together with the first electrode 120 to generate a potential difference. The second electrode 160 may be a metal, a metal alloy, semimetal) or a light-transparent transparent oxide. The second electrode 160 may be formed of a metal such as Fe, Ag, Au, Cu, Cr, W, Al, Mo, Zn, Ni, Pt, Pd, Co, In, Mn, Si, Ta, , V, Ru, Ir, Zr, Rh, Mg, ITO, FTO, AZO, GZO, IZO and PEDOT: PSS.

The perovskite solar cell according to the embodiment of the present invention can exhibit excellent photoelectric conversion efficiency including a perovskite photoactive layer having no pinhole, dense and excellent morphology.

Specifically, the perovskite solar cell according to the embodiment of the present invention can greatly improve the crystallinity of the perovskite photoactive layer by using only the mechanical pressing method for a short period of time without any post-treatment or chemical treatment have.

Hereinafter, examples and comparative examples of the present invention will be described. The following examples illustrate the invention and are not intended to limit the scope of the invention.

Example 1: Preparation of perovskite photoactive layer

The indium tin oxide (ITO) glass substrate, which is a transparent electrode substrate, was washed with acetone and 2-propanol and further washed in an ultraviolet / ozone (UV / OZONE) washer for 30 minutes. PEDOT: PSS was spin-coated on the cleaned transparent electrode substrate as a hole transport layer at 4,000 rpm for 30 seconds and then heat-treated at 150 ° C for 10 minutes using a hot plate.

The perovskite precursor solution was prepared by mixing N, N-dimethylmethanamide and dimethylsulfoxide in a 1: 1 molar ratio of lead iodide (PbI ₂ ) and methylammonium iodide (CH ₃ NH ₃ I) In a mixed solvent.

The prepared perovskite precursor solution was spin-coated on the prepared PEDOT: PSS substrate to form a perovskite precursor film. A polyurethane-acrylate (PUA) mold having a nanodot of 250 nm was placed on the prepared perovskite precursor film and a pressure of 1.6 kgf / cm ^{2 was} applied at a temperature of 100 ° C for 9 seconds. Subsequently, heat treatment was performed at a temperature of 100 占 폚 for 10 minutes in a state where no pressure was applied.

At this time, a perovskite photoactive layer having a nano dot pattern having a total thickness of 380-400 nm was prepared.

Example 2: Preparation of perovskite solar cell

The perovskite photoactive layer prepared in Example 1 was spin-coated with PCBM (Phenyl C61 butyric acid methyl ester) solution dispersed in chlorobenzene and spin coated with BCP (bathocuproine) solution to form an electron transport layer . Then, a silver (Ag) electrode was formed using a thermal evaporator and a metal mask to finally produce a perovskite solar cell.

Comparative Example 1: Production of perovskite photoactive layer

The ITO glass substrate, which is a transparent electrode substrate, was washed with acetone and 2-propanol, and further washed in an ultraviolet / ozone washing machine for 30 minutes. PEDOT: PSS was spin-coated on the cleaned transparent electrode substrate as a hole transport layer at 4,000 rpm for 30 seconds and then heat-treated at 150 ° C for 10 minutes using a hot plate.

The perovskite precursor solution was prepared by dissolving lead iodide (PbI ₂ ) and methylammonium iodide (CH ₃ NH ₃ I) in a mixed solvent of dimethylformamide and dimethylsulfoxide in a molar ratio of 1: 1.

The prepared perovskite precursor solution was spin-coated on the prepared PEDOT: PSS substrate to form a perovskite precursor film. The perovskite precursor film thus prepared was heat-treated at a temperature of 100 캜 for 10 minutes in a state of not applying pressure.

At this time, a flat perovskite photoactive layer having a total thickness of 380-400 nm was produced.

Comparative Example 2: Production of perovskite solar cell

The perovskite photoactive layer prepared in Comparative Example 1 was spin-coated with a PCBM solution dispersed in chlorobenzene, and the BCP solution was spin-coated to form an electron transport layer. Then, a silver (Ag) electrode was formed using a thermal evaporator and a metal mask to finally produce a perovskite solar cell.

Scanning electron microscope (SEM) image analysis of perovskite photoactive layer

SEM images of the perovskite photoactive layer prepared in Example 1 and Comparative Example 1 were observed in order to confirm a scanning electron microscope (SEM) image of the perovskite photoactive layer according to an embodiment of the present invention.

3 to 4, the perovskite photoactive layer produced in Example 1 has a larger crystal size and dense morphology than the perovskite photoactive layer produced in Comparative Example 1 , The crystal grain boundary angle is decreased, and the perovskite crystal forming the photoactive layer with few defects is obtained.

Photoelectric conversion efficiency analysis of perovskite solar cell

In order to confirm the performance of the perovskite solar cell according to the embodiment of the present invention, the photoelectric conversion efficiency of the perovskite solar cell manufactured in Example 2 was measured with a solar simulator. The measured values of the open-circuit voltage (VOC), the short-circuit current density (JSC), the filling factor (FF) and the photoelectric conversion efficiency (η) of the measured solar cell were AM 1.5 (1sun, 100 mW / cm ² ) Table 1 shows the results.

Open-circuit voltage
(V) Short circuit current density
(mA / cm ² ) Fill factor
(%) Photoelectric conversion efficiency
(%) Example 2 0.94 20.49 81.08 15.61 Comparative Example 2 0.87 17.50 81.94 12.49

Referring to Table 1, it can be seen that the open-circuit voltage and the short-circuit current density of Example 2 are significantly improved as compared with Comparative Example 2, thereby increasing the light conversion efficiency from 12.49% to 15.61%.

FIG. 5 is a current-voltage graph of the perovskite solar cell manufactured in Example 2, and FIG. 6 is a graph of external quantum efficiency (EQE) of the perovskite solar cell manufactured in Example 2. FIG.

Referring to FIGS. 5 and 6, it can be seen that the open-circuit voltage and the short-circuit current density of Example 2 are significantly improved as compared with Comparative Example 2. As can be seen from the external quantum efficiency graph, the quantum efficiency is improved in all the wavelength regions It can be confirmed that the current density is improved.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

110: substrate
120: first electrode
130: hole transport layer
140: perovskite photoactive layer
150: electron transport layer
160: Second electrode

Claims (6)

Coating a perovskite precursor solution on the substrate to form an intermediate perovskite precursor film;
Wherein the intermediate state of the perovskite in the precursor film for 3 seconds to 15 seconds while applying a pressure of 1.0 kgf / cm ² to 2.0 kgf / cm ² 1 primary heat treatment; And
Performing a secondary heat treatment on the pressed perovskite precursor film to form a perovskite photoactive layer
Lt; / RTI >
In the intermediate state of the perovskite precursor film, crystal growth and crystal growth progress in the step of applying the pressure and the first heat treatment,
The step of applying the pressure and performing the first heat treatment may be performed by applying pressure to a nanoimprinting method including a nano pattern and controlling the height of the nano pattern, the distance between patterns, or the size of the pattern, A method for producing a perovskite photoactive layer that controls crystallinity and optical properties.
The method according to claim 1,
Wherein the first heat treatment is performed at a temperature of 60 ° C to 120 ° C.
The method according to claim 1,
Wherein the second heat treatment is performed at a temperature of 60 ° C to 120 ° C for 1 minute to 30 minutes.
The method according to claim 1,
Wherein the coating is performed by any one method selected from the group consisting of spin coating, dip coating, and spray coating.
Board;
A first electrode formed on the substrate;
A hole transport layer formed on the first electrode;
A perovskite photoactive layer formed on the hole transporting layer and produced by the method of any one of claims 1 to 4;
An electron transport layer formed on the perovskite photoactive layer; And
A second electrode formed on the electron transport layer,
A perovskite solar cell.
6. The method of claim 5,
Wherein the perovskite photoactive layer has a thickness of 100 nm to 1000 nm.

Images