WO2022035239A1

WO2022035239A1 - Method for preparing perovskite optoelectronic device and perovskite optoelectronic device prepared thereby

Info

Publication number: WO2022035239A1
Application number: PCT/KR2021/010692
Authority: WO
Inventors: 임상혁; 허진혁
Original assignee: 고려대학교 산학협력단
Priority date: 2020-08-11
Filing date: 2021-08-11
Publication date: 2022-02-17
Also published as: KR102300107B1

Abstract

Disclosed are a perovskite optoelectronic device and porous polymer particles prepared by means of same. The present invention comprises the steps of: forming an electron transport layer on a first electrode; forming a photoactive layer comprising a perovskite compound on the electron transport layer by means of orthogonal spray coating; forming a hole transport layer on the photoactive layer comprising the perovskite compound; and forming a second electrode on the hole transport layer, wherein the photoactive layer comprising the perovskite compound has a composition gradient in the depth direction from the hole transport layer to the electron transport layer.

Description

Method for manufacturing perovskite optoelectronic device and perovskite optoelectronic device manufactured through the same

The present invention relates to a method of manufacturing a perovskite optoelectronic device and a perovskite optoelectronic device manufactured through the method, and more particularly, by using spray coating to form a photoactive layer to have a compositional gradient in the depth direction, The present invention relates to a method for manufacturing a perovskite optoelectronic device capable of improving absorption wavelength range and carrier lifetime, and to a perovskite optoelectronic device manufactured through the same.

In order to solve the global environmental problems caused by the depletion of fossil energy and its use, research on renewable and clean alternative energy sources such as solar energy, wind power, and hydroelectric power is being actively conducted.

Among them, interest in solar cells that directly change electrical energy from sunlight is increasing significantly. Here, the solar cell refers to a cell that generates current-voltage using the photovoltaic effect of absorbing light energy from sunlight to generate electrons and holes.

Currently, it is possible to manufacture np diode-type silicon (Si) single-crystal-based solar cells with a light energy conversion efficiency of more than 20%, which is used in actual photovoltaic power generation. Compound semiconductors such as gallium arsenide (GaAs) with better conversion efficiency There are also solar cells using However, since these inorganic semiconductor-based solar cells require very high-purity purified materials for high efficiency, a lot of energy is consumed for refining raw materials, and expensive process equipment is required for single crystal or thin film using raw materials. There is a limit to lowering the manufacturing cost of solar cells, which has been an obstacle to large-scale utilization.

Accordingly, in order to manufacture a solar cell at a low cost, it is necessary to significantly reduce the cost of the core material or manufacturing process of the solar cell, and as an alternative to the inorganic semiconductor-based solar cell, the dye-sensitized solar cell and Organic solar cells are being actively researched.

Dye-sensitized solar cell (DSSC) was first successfully developed in 1991 by Professor Michael Gratzel of Lausanne Institute of Technology (EPFL) in Switzerland and introduced in Nature (Vol. 353, p. 737). became The initial structure of the dye-sensitized solar cell was a simple structure in which a light-absorbing dye was adsorbed to a porous photoanode on a transparent electrode film that conducts light and electricity, another conductive glass substrate was placed on top, and a liquid electrolyte was filled. is made of

The highest efficiency reported so far for liquid-type dye-sensitized solar cells has remained at 11-12% for about 20 years. Although the liquid-type dye-sensitized solar cell has relatively high efficiency, it has potential for commercialization, but there are also problems with stability over time due to volatile liquid electrolytes and cost reduction due to the use of expensive ruthenium (Ru)-based dyes.

On the other hand, organic photovoltaic (OPV) cells, which have been studied in earnest since the mid-1990s, are organic materials with electron donor (D, or sometimes called hole acceptor) characteristics and electron acceptor (A) characteristics. is composed of When a solar cell made of organic molecules absorbs light, electrons and holes are formed, which is called exciton. Excitons move to the D-A interface to separate charges, and electrons move to electron acceptors and holes move to electron donors to generate photocurrent.

Since the exciton generated from the electron donor can normally travel at a very short distance of around 10 nm, the photoreactive organic material cannot be thickly stacked, resulting in low light absorption and low efficiency. However, recently, with the introduction of the so-called BHJ (bulk heterojuction) concept that increases the surface area at the interface and the development of an electron donor organic material with a small bandgap that is easy to absorb in a wide range of sunlight, the efficiency has greatly increased, so that 8% An organic solar cell with higher efficiency has been reported (Advanced Materials, 23 (2011) 4636).

The organic solar cell has a simpler manufacturing process compared to the conventional solar cell due to the easy processability, diversity, and low cost of organic materials. However, the organic solar cell has a big problem in that the structure of the BHJ is deteriorated by moisture or oxygen in the air, so that the efficiency is rapidly reduced, that is, the stability of the solar cell. As a way to solve this problem, stability can be increased by introducing a complete sealing technology, but there is a problem that the price increases.

In addition, an efficiency of about 9% has been reported by using a material having an organic/inorganic hybrid perovskite structure instead of a pure inorganic quantum dot instead of a dye in a dye-sensitized solar cell (Scientific Reports 2, 591). .

Organic-inorganic hybrid perovskite is a next-generation light-absorbing material with excellent optical and electrical properties, low price, and easy use in the process. In particular, recent organic-inorganic hybrid perovskite semiconductors have a basic chemical composition of ABX ₃ , so they can be easily synthesized with various types of materials, and solar cells can be manufactured at low material costs, making them the ultimate next-generation solar cell material. It's getting a lot of attention.

In addition, as perovskite solar cells can be solution-processed like organic solar cells, they can be used in a wide variety of large-area and flexible devices. .

On the other hand, since the core technology for achieving high efficiency in perovskite solar cells largely depends on the formation of a uniform perovskite film, for commercial application to perovskite solar cells, the It is important to develop skills for shaping.

The method of manufacturing a perovskite film includes a method of forming a uniform perovskite film by slowing the crystallization rate by controlling the solubility of the perovskite solution, and forcing the perovskite film through nonsolvent dripping. There is a method of crystallization, a method of forming a perovskite film by first coating PbI ₂ , etc., and then dripping MAI solution or the like thereto (two step process).

However, in the case of these methods, it is difficult to form a uniform perovskite film because it is greatly affected by the external environment (temperature, humidity), it is difficult to control the size of the perovskite crystal grains, and it is difficult to achieve rapid crystallization and unevenness. The surface roughness increases due to growth, which reduces the quality of the perovskite film, and the non-compressed film has disadvantages in forming numerous defects such as non-uniform particle size and external erosion caused by pinholes.

In addition, the rough surface of the perovskite film has a problem that recombination occurs due to poor contact between the perovskite film and the charge transport layer. There is a disadvantage in that it is difficult to manufacture a lobskite solar cell.

In order to manufacture a high-efficiency perovskite solar cell, it is necessary to develop a technology capable of forming a perovskite film with uniform and large grains in a large area regardless of the size of the substrate, and to ensure long-term operation stability. do.

In an embodiment of the present invention, a photoactive layer containing a perovskite compound is formed to have a composition gradient in the depth direction from the hole transport layer to the electron transport layer by a spray coating method to absorb sunlight (1-sun light soaking) An object of the present invention is to provide a perovskite photoelectric device capable of improving long-term operation stability so as to have less than 10% degradation even when continuously operated for 1000 hours under the present invention, and a method for manufacturing the same.

In an embodiment of the present invention, the photoactive layer containing the perovskite compound is formed to have a composition gradient in the depth direction from the hole transport layer to the electron transport layer, and the absorption wavelength is expanded to 750 nm to increase the light collecting property ( An object of the present invention is to provide a perovskite optoelectronic device capable of improving light harvesting and a method for manufacturing the same.

In an embodiment of the present invention, the perovskite film can be manufactured in a large area regardless of the size of the substrate through a relatively simple process by forming a photoactive layer containing a perovskite compound by a spray coating method. An object of the present invention is to provide an optoelectronic device and a method for manufacturing the same.

A method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention comprises: forming an electron transport layer on a first electrode; forming a photoactive layer comprising a perovskite compound on the electron transport layer by spray coating (orthogonal spray coating); forming a hole transport layer on the photoactive layer containing the perovskite compound; and forming a second electrode on the hole transport layer, wherein the photoactive layer including the perovskite compound has a composition gradient in the depth direction from the hole transport layer to the electron transport layer. .

In the photoactive layer including the perovskite compound, a band structure gradient may be continuously formed in a depth direction from the hole transport layer to the electron transport layer.

At least one electric field may be formed therein in the photoactive layer including the perovskite compound.

The perovskite compound may be represented by the following formula (1).

[Formula 1]

AaMmXc

(In Formula 1, when A is a monovalent cation, M is a divalent or trivalent metal cation, X is a monovalent anion, and M is a divalent metal cation, a+2b=c, M is a trivalent metal For positive ions, a+3b=c, and a, b, and c are natural numbers.)

The perovskite compound may be represented by the following formula (2).

[Formula 2]

AM'X' _(3-m) X" _m

(In Formula 2, A is a monovalent cation, M' is a divalent metal cation, X' and X" are monovalent anions, and m is 0≤m≤1.)

The perovskite compound may include at least two or more monovalent anions, and the composition ratio of the at least two or more monovalent anions may change in the depth direction.

Forming a photoactive layer comprising a perovskite compound by spray coating on the electron transport layer may include: coating a first perovskite compound on the electron transport layer; and coating a second perovskite compound on the coated first perovskite compound.

In the photoactive layer comprising the perovskite compound in contact with the electron transport layer, the concentration of the first perovskite compound is higher than the concentration of the second perovskite compound, and the perovskite in contact with the hole transport layer In the photoactive layer including the dot compound, the concentration of the second perovskite compound may be higher than that of the first perovskite compound.

The coating time of the second perovskite compound may be 0.5 seconds to 200 seconds.

It may include adjusting the average diameter of the perovskite compound according to the coating time of the second perovskite compound.

The first perovskite compound may be represented by the following Chemical Formula 3, and the second perovskite compound may be represented by the following Chemical Formula 4.

[Formula 3]

AM'X' _2X "

[Formula 4]

AM'X' ₃

(In

Formulas

3 and 4, A is a monovalent cation, M' is a divalent metal cation, and X' and X" are monovalent anions.)

Perovskite according to an embodiment of the present invention is a first electrode; an electron transport layer formed on the first electrode; a photoactive layer formed by orthogonal spray coating on the electron transport layer and including a perovskite compound; a hole transport layer formed on the photoactive layer including the perovskite compound; and a second electrode formed on the hole transport layer, wherein the photoactive layer including the perovskite compound has a composition gradient in a depth direction from the hole transport layer to the electron transport layer.

The perovskite compound may be represented by the following formula (1).

[Formula 1]

AaMmXc

The photoactive layer may be a perovskite compound represented by the following Chemical Formula 2.

[Formula 2]

AM'X' _(3-m) X" _m

The photoactive layer comprising the perovskite compound comprises a first perovskite compound and a second perovskite compound, and the photoactive layer comprising the perovskite compound in contact with the electron transport layer is a first The concentration of the first perovskite compound is higher than the concentration of the second perovskite compound, and the photoactive layer including the perovskite compound in contact with the hole transport layer has a second perovskite compound concentration. It can be higher than 1 perovskite compound.

According to an embodiment of the present invention, the photoactive layer containing the perovskite compound is formed to have a composition gradient in the depth direction from the hole transport layer to the electron transport layer by a spray coating method to absorb sunlight (1-sun light). Soaking), it is possible to improve long-term operation stability so as to have less than 10% degradation even when continuously operated for 1000 hours.

According to an embodiment of the present invention, the photoactive layer containing the perovskite compound is formed to have a composition gradient in the depth direction from the hole transport layer to the electron transport layer to expand the absorption wavelength to 750 nm. Light harvesting can be improved.

According to an embodiment of the present invention, the photoactive layer containing the perovskite compound is formed by a spray coating method, and the perovskite film can be manufactured in a large area regardless of the size of the substrate through a relatively simple process.

1 is a flowchart illustrating a method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention.

2 is a cross-sectional view illustrating a perovskite optoelectronic device according to an embodiment of the present invention.

3 is an image illustrating a band diagram of a perovskite optoelectronic device according to an embodiment of the present invention.

4 to 11 show the characteristics of change in morphology variations of the photoactive layer according to the spray coating time.

4 is a cross-sectional scanning electron microscopy (SEM) image of a photoactive layer prepared by spray coating for 5 seconds, and FIG. 5 is a surface scanning electron microscope image.

6 is a cross-sectional scanning electron microscope image of a photoactive layer prepared by spray coating for 10 seconds, and FIG. 7 is a surface scanning electron microscope image.

8 is a cross-sectional scanning electron microscope image of a photoactive layer prepared by spray coating for 15 seconds, and FIG. 9 is a surface scanning electron microscope image.

10 is a cross-sectional scanning electron microscope image of the photoactive layer prepared by spray coating for 20 seconds, and FIG. 11 is a surface scanning electron microscope image.

12 shows a grazing incidence X-ray diffraction (GIXRD) graph of the penetration depth of the photoactive layer according to the spray coating time.

13 is a grazing incidence X-ray diffraction graph of the photoactive layer prepared by spray coating for 5 seconds, FIG. 14 is a graph showing spray coating for 10 seconds, and FIG. 15 is spray coating for 15 seconds. It is a graph in progress, and FIG. 16 is a graph in which spray coating was performed for 20 seconds.

17 is a graph showing the depth profile of the (200) peak position of the photoactive layer according to the spray coating time.

18 is a graph showing the correlation between the Br/Pb composition ratio (y) and the (200) peak position (x).

19 is a graph showing compositional depth profiles of the photoactive layer according to spray coating time.

20 is a graph showing the depth profile of the electronic bandgap (Eg) of the photoactive layer according to the spray coating time.

21 is a graph illustrating depth profiles of conduction band minimum (CBM) and valence band maximum (VBM) of the photoactive layer according to spray coating time.

22 is a scanning electron microscope image of a perovskite photoelectric device according to an embodiment of the present invention including a photoactive layer prepared by spray coating for 15 seconds.

23 is a graph showing an absorption spectrum of a perovskite photoelectric device according to an embodiment of the present invention, FIG. 24 is a graph showing an external quantum efficiency spectrum (EQE spectra), and FIG. 25 is an open It is a graph showing the voltage (Voc), Fig. 26 is a graph showing the short-circuit current (Jsc), Fig. 27 is a graph showing the charging factor (FF), and Fig. 28 is a graph showing the energy conversion efficiency (PCE) It is a graph.

29 is a graph showing current density-voltage curves (JV curves) of a perovskite photoelectric device according to an embodiment of the present invention including a photoactive layer prepared by spray coating for 5 seconds, FIG. 30 is It is a graph of spray coating for 10 seconds, FIG. 31 is a graph of spray coating for 15 seconds, and FIG. 32 is a graph showing spray coating for 20 seconds.

33 is an image showing a sub-module of a perovskite optoelectronic device according to an embodiment of the present invention, FIG. 34 is a graph showing a photocurrent-voltage (IV) curve of the sub-module, and FIG. 35 is an initial stage ( It is a graph showing the stabilized power output (Stabilized power output) of the sub-module in early stage), and FIG. 36 is 1-sun illumination at room temperature and nitrogen (N2) atmosphere of the sub-module that is not encapsulated. It is a graph showing the results of a long-term light-soaking stability test under

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

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements, steps, or elements mentioned.

As used herein, “embodiment”, “example”, “aspect”, “exemplary”, etc. are to be construed as advantageous in any aspect or design described as being preferred or advantageous over other aspects or designs. is not doing

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'. That is, unless stated otherwise or clear from context, the expression 'x employs a or b' means any of natural inclusive permutations.

Also, as used herein and in the claims, the singular expression "a" or "an" generally means "one or more," unless stated otherwise or clear from the context that it relates to the singular form. should be interpreted as

The terms used in the description below have been selected as general and universal in the related technical field, but there may be other terms depending on the development and/or change of technology, customs, preferences of technicians, and the like. Therefore, the terms used in the description below should not be construed as limiting the technical idea, but as illustrative terms for describing the embodiments.

In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the corresponding description. Therefore, the terms used in the description below should be understood based on the meaning of the term and the content throughout the specification, rather than the simple name of the term.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

Meanwhile, in the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms used in this specification are terms used to properly express the embodiment of the present invention, which may vary according to the intention of a user or operator or customs in the field to which the present invention belongs. Accordingly, definitions of these terms should be made based on the content throughout this specification.

The method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention comprises the steps of forming an electron transport layer on the first electrode (S110), spray coating on the electron transport layer (orthogonal spray coating) on the perovskite compound. Forming a photoactive layer comprising (S120), forming a hole transport layer on the photoactive layer comprising a perovskite compound (S130), and forming a second electrode on the hole transport layer (S140) do.

The method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention proceeds with the step of forming an electron transport layer on the first electrode (S110).

As the substrate, an inorganic substrate or an organic substrate may be used.

The inorganic substrate may include at least one of glass, quartz, Al ₂ O ₃ , SiC, Si, GaAs, and InP.

The organic substrate is Kepton foil, polyimide (PI), polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN) ), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polycarbonate (PC), cellulose triacetate (CTA) and cellulose acetate It may include any one of propionate (cellulose acetate propionate, CAP).

It is more preferable that the inorganic substrate and the organic substrate are made of a transparent material through which light is transmitted, and in general, the substrate can be used as long as it can be positioned on the front electrode. When the organic substrate is introduced, the flexibility of the electrode can be increased.

The first electrode is located on the substrate and a conductive electrode, in particular a transparent conductive electrode, is preferred to enhance the transmission of light. The first electrode may be used as long as it is an electrode material commonly used in the field of solar cells.

The first electrode contains, for example, fluorine doped tin oxide (FTO), indium doped tin oxide (ITO), aluminum-doped zinc oxide (AZO) and indium. At least one of indium doped zinc oxide (IZO) may be included.

The electron transport layer may be positioned between the first electrode and the photoactive layer. The electron transport layer may allow electrons generated in the photoactive layer to be easily transferred to the first electrode.

The electron transport layer may include at least one of fullerene (C60), a fullerene derivative, perylene, polybenzimidazole (PBI), and PTCBI (3,4,9,10-perylene-tetracarboxylic bis-benzimidazole), , the fullerene derivative may include at least one of PCBM ((6,6)-phenyl-C61-butyric acid-methylester) and PCBCR ((6,6)-phenyl-C61-butyric acid cholesteryl ester), but in this It is not limited.

However, a TiO ₂ based or Al ₂ O ₃ based porous material may be used as the electron transport layer in the inverted structure, but is not limited thereto.

Thereafter, the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention proceeds with the step (S120) of forming a photoactive layer containing a perovskite compound by spray coating on the electron transport layer.

The photoactive layer may serve as a photoelectric conversion layer that generates current by separating electrons (e) and holes (h).

The photoactive layer including the perovskite compound has a composition gradient in the depth direction from the hole transport layer to the electron transport layer by spray coating.

Preferably, the photoactive layer having a composition gradient in the depth direction may be formed by performing orthogonal processable spray coating.

In the case of a general solution process (in the case of general spin coating), when the first perovskite film is formed, and then the second perovskite film is formed, the solvent contained in the perovskite solution for forming the second perovskite film Since the first perovskite film is dissolved in the

In addition, in the case of vacuum deposition without using a solvent, since there is no intermixing by solvent between the first perovskite film and the second perovskite film, a perovskite multilayer thin film is formed in a vertical direction. However, the process is complicated and it is difficult to form in a large area.

On the other hand, since the method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention uses orthogonal spray coating that can coat the perovskite multilayer thin film in a vertical direction, a solution is used, but the spray-coated When the micro-drops fall, the solvent is evaporated instantaneously to form a multi-layer thin film in a vertical direction like vacuum deposition, and a small amount of solvent remains between the first perovskite thin film formed in the lower layer and the newly formed thin film. Inter mixing may take place to produce a perovskite film having a continuous composition change.

As a spray coater used for spray coating, various spray coaters such as an air brush, ultrasonic spray, mega sonic spray, or electrospray may be used.

The method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention is not limited to a spray coater, but when ultrasonic spray coating is used, a micro drop of the sprayed perovskite solution is used. ) is small, so it is easy to precisely control in terms of process.

Spray coating can be performed while moving the spray nozzle at a speed of 0.001 m/min to 20 m/min. If the spray nozzle is moved at a speed of less than 0.001 m/min, the process speed is too slow, and 20 m/min. If it exceeds , the moving speed is excessively fast, so it is difficult to obtain a uniform inclined wall without pinholes.

The discharge amount discharged to the spray nozzle may be 0.001 ml/min to 1000 ml/min, and when the discharge amount is less than 0.001 ml/min, the amount of the solution containing the perovskite compound sprayed from the spray nozzle is small, so that the solvent is There is a disadvantage that the process time is prolonged because all of them are blown away or the amount applied is small, and when it exceeds 1000 ml/min, an excess solution is applied and it is difficult to obtain a uniform film because it is difficult to dry.

In the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention, a photoactive layer containing a perovskite compound is formed by a spray coating method, and the perovskite film is formed through a relatively simple process regardless of the size of the substrate. It can be manufactured in a large area.

The method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention proceeds with the step (S120) of forming a photoactive layer containing the perovskite compound by spray coating on the electron transport layer, the perovskite compound The photoactive layer containing may have a composition gradient in the depth direction from the hole transport layer to the electron transport layer.

The perovskite compound may include a metal halide.

Specifically, the perovskite compound of the photoactive layer having a composition gradient in the depth direction from the hole transport layer to the electron transport layer may be represented by the following formula (1).

[Formula 1]

AaMmXc

A is C _1-24 straight or branched chain alkyl, amine group (-NH ₃ ), hydroxyl group (-OH), cyano group (-CN), halogen group, nitro group (-NO), methoxy group (-OCH ₃ ) Or imidazolium group substituted C _1-24 straight or branched chain alkyl, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Fr ⁺ , Cu(I) ⁺ , Ag(I) ⁺ and Au(I) ) may include at least one of ⁺ .

M' is Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , Cu ²⁺ , Co ²⁺ , Ni ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ , Rf ²⁺ , In ³⁺ , Bi ³⁺ , Co ³⁺ , Sb ³⁺ , Ni ³⁺ , Al ³⁺ , Ga ³⁺ , Tl ³⁺ , Sc ³⁺ , Y ³⁺ , La ³⁺ , Ce ³⁺ , Fe ³⁺ , Ru ³⁺ , Cr ³⁺ , V ³⁺ , and Ti ³⁺ may be included.

X may include at least one of F ^- , Cl ^- , Br ^- , I ^- , SCN ^- , PF ₆ ^- , and BF ₄ ^- .

For example, the perovskite compound of Chemical Formula 1 of the photoactive layer having a composition gradient in the depth direction from the hole transport layer to the electron transport layer may be represented by Chemical Formula 2 below.

[Formula 2]

AM'X' _(3-m) X" _m

According to an embodiment, in the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention, the step of forming a photoactive layer containing a perovskite compound by spray coating on the electron transport layer (S120) is on the electron transport layer It may include the step of coating the first perovskite compound on (S121) and coating the second perovskite compound on the coated first perovskite compound (S122).

First, the step of coating the first perovskite compound on the electron transport layer (S121) may proceed.

Specifically, the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention is prepared by spray-coating a first perovskite compound precursor solution containing a first perovskite compound and a solvent on an electron transport layer. 1 A perovskite compound film can be formed.

The coating time of the first perovskite compound is proportional to the area to be coated, and based on the perovskite area of 1 cm ² , 0.1 seconds to 600 seconds (1 cm/(20 m/minute) = minutes/2000 = 0.03 seconds) to 1 cm/(0.001 m/min)=min/0.1=10 min=600 sec).

If the coating time of the first perovskite compound is less than 0.1 seconds, the amount of the first perovskite compound to be coated is too small, so the efficiency of the device is low, and if it exceeds 600 seconds, the first perovskite compound to be coated There are disadvantages in that the efficiency of the device is lowered or the process time is too long because the amount of the compound is too large.

Spray coating of the first perovskite compound can be performed while moving the spray nozzle at a speed of 0.001 m/min to 20 m/min, and the process speed is too high when the spray nozzle is moved at a speed of less than 0.001 m/min. There is a disadvantage that it is slow, and when it exceeds 20 m/min, the moving speed is excessively fast, so it is difficult to obtain a uniform inclined wall without a pin hole.

When the first perovskite compound is spray coated, the discharge amount discharged to the spray nozzle may be 0.001ml/min to 1000ml/min, and when the discharge amount is less than 0.001ml/min, the first perovskite compound sprayed from the spray nozzle The amount of the solution contained is small, so that all the solvent is blown away before it reaches the substrate or the amount of application is small, so the process time is long. The disadvantage is that it is difficult to obtain.

For example, the first perovskite compound may be represented by Formula 3 below.

[Formula 3]

AM'X' _2X "

(In Formula 3, A is a monovalent cation, M' is a divalent metal cation, and X' and X" are monovalent anions.)

Preferably, the first perovskite compound may be CsPbI ₂ Br.

Thereafter, the step of coating the second perovskite compound on the coated first perovskite compound (S122) may be performed.

Specifically, in the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention, a second perovskite compound precursor solution containing a second perovskite compound and a solvent is mixed with a first perovskite compound film. It is possible to form a photoactive layer having a composition gradient in the depth direction from the hole transport layer to the electron transport layer by spray coating on it.

The spray coating of the second perovskite compound can be performed while moving the spray nozzle at a speed of 0.001 m/min to 20 m/min, and if the spray nozzle is moved at a speed of less than 0.001 m/min, the process speed is too high There is a disadvantage that it is slow, and when it exceeds 20 m/min, the moving speed is excessively fast, so it is difficult to obtain a uniform inclined wall without a pin hole.

When the second perovskite compound is spray coated, the discharge amount discharged to the spray nozzle may be 0.001ml/min to 1000ml/min, and when the discharge amount is less than 0.001ml/min, the second perovskite compound sprayed from the spray nozzle The amount of the solution contained is small, so that all the solvent is blown away before it reaches the substrate or the amount of application is small, so the process time is long. The disadvantage is that it is difficult to obtain.

For example, the second perovskite compound may be represented by Formula 4 below.

[Formula 4]

AM'X' ₃

(In Formula 4, A is a monovalent cation, M' is a divalent metal cation, and X' and X" are monovalent anions.)

Preferably, the second perovskite compound may be CsPbI ₃ .

In the method for manufacturing a perovskite optoelectronic device according to an embodiment of the present invention, as the coating time of the second perovskite compound increases, the second perovskite compound-derived monovalent anion (eg, the second halide ion) ), the composition of at least two or more monovalent anions of the perovskite compound (eg, a first halide ion and a second halide ion) may be changed.

The perovskite compound of Chemical Formula 1 of the photoactive layer having a compositional gradient in the depth direction from the hole transport layer to the electron transport layer is represented by the following Chemical Formula 2, the first perovskite compound is represented by Chemical Formula 3, and the second compound When the rovskite compound is represented by Chemical Formula 4, in the method for manufacturing a perovskite photoelectric device according to an embodiment of the present invention, as the coating time of the second perovskite compound increases, X' and The composition of X" can be varied.

More specifically, when using CsPbI ₂ Br as the first perovskite compound and CsPbI ₃ as the second perovskite compound, as the coating time of the CsPbI ₃ precursor solution increases, I is increased, and Br, which is X", is decreased, and the composition is changed so that the photoactive layer has CsPbI _3.00 , CsPbI _2.75 Br _0.25 , CsPbI _2.50 Br _0.05 , CsPbI _2.25 Br _0.75 and CsPbI _2.00 Br ₁ , thereby increasing the compositional gradient in the depth direction. can have

Therefore, the perovskite compound contains at least two or more monovalent anions, and the composition ratio of at least two or more monovalent anions in the depth direction is changed, so that the band gap and Fermi level of the photoactive layer are continuously changed. can be formed.

Furthermore, in the perovskite compound, the composition ratio of X″/M′ may be changed in the depth direction.

In the photoactive layer containing the perovskite compound, when the X"/M' composition ratio of the perovskite compound is changed in the depth direction from the hole transport layer to the electron transport layer, the band gap and the Fermi level of the photoactive layer are changed continuously A band structure gradient may be formed.

Therefore, in the case of a solar cell, when the X"/M' composition ratio of the perovskite compound is continuously changed in the depth direction, the bandgap and Fermi level are continuously changed, so that the generated charges can be separated and moved more effectively without recombination. can

In addition, for example, when using CsPbI ₂ Br as the first perovskite compound and CsPbI ₃ as the second perovskite compound, as the coating time of the second perovskite compound increases , because the composition of X" is increased, the composition ratio of X"/M' in the depth direction of the photoactive layer may be increased.

In addition, in the photoactive layer comprising the perovskite compound in contact with the electron transport layer, the concentration of the first perovskite compound is higher than the concentration of the second perovskite compound, and the perovskite compound in contact with the hole transport layer The concentration of the second perovskite compound in the photoactive layer comprising a may be higher than that of the first perovskite compound.

Specifically, in the method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention, a first perovskite compound is coated on an electron transport layer, and then a second perovskite compound is coated to form a photoactive layer After that, since the hole transport layer is formed, the perovskite compound in contact with the hole transport layer, which is the upper surface portion of the photoactive layer on which the second perovskite compound is coated, has a concentration of the second perovskite compound in the first It may be higher than the concentration of the perovskite compound.

According to an embodiment, the photoactive layer including the perovskite compound in contact with the electron transport layer may include only the first perovskite compound, or the photoactive layer comprising the perovskite compound in contact with the hole transport layer 2 It may also contain only perovskite compounds.

The photoactive layer containing the perovskite compound absorbs light to generate electron-hole pairs, and the generated electrons move to the first electrode through the electron transport layer, and at the same time, the holes move to the second electrode through the hole transport layer . At this time, when the two electrodes are connected, electricity may continuously flow while electrons move to the counter electrode through an external circuit.

Therefore, the perovskite optoelectronic device manufactured by the method for manufacturing a perovskite optoelectronic device according to an embodiment of the present invention is a photoactive layer comprising a perovskite compound in contact with the electron transport layer and the perovskite in contact with the hole transport layer Electron-hole pairs can be created in the photoactive layer containing the skyte compound, leading to the electrons and holes moving in opposite directions across the photoactive layer to the electron transport layer and hole transport layer, improving charge collection ability can be

In addition, since the photoactive layer including the perovskite compound has a composition gradient in the depth direction, at least one electric field may be formed therein.

In general, in the case of a perovskite optoelectronic device, an electric field is formed at the interface where the electron transport layer and the photoactive contact and the photoactive layer and the hole transport layer contact each other. As the silver second perovskite compound is coated, Fermi level matching occurs at the interface between the first perovskite compound and the second perovskite compound, and through this, an additional electric field is generated inside the photoactive layer. Electron-hole pairs generated inside the photoactive layer are separated and moved much more effectively, so that the efficiency of the photoelectric device can be increased.

The coating time of the second perovskite compound may be 0.5 seconds to 200 seconds, and if the coating time of the second perovskite compound solution is less than 5 seconds, the coating amount of the second perovskite compound is too small, the composition It is difficult to manufacture the photoactive layer having an inclination, and when it exceeds 200 seconds, the surface roughness becomes too large, and it is difficult to form a uniform hole transport layer, so that device efficiency is lowered.

In addition, the average diameter of the perovskite compound may be adjusted according to the coating time of the second perovskite compound.

In general, the average diameter of the perovskite compound particles can be continuously increased during the spray coating process, with dissolution and regrowth.

However, in the method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention, since the second perovskite compound has lower solubility in a solvent than the first perovskite compound, the second perovskite compound When spray-coated on the first perovskite compound, the second perovskite compound is rapidly nucleated to a higher nuclei density than the first perovskite compound, so that the average perovskite compound particles The diameter may be reduced.

In addition, as the spray coating time of the second perovskite compound is increased, the trap or exciton binding energy can be adjusted.

When the spray coating time of the second perovskite compound is increased, the diameter of the perovskite compound particles is reduced, so that the interfacial trap is increased, and the exciton binding energy can be increased.

Thereafter, the method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention proceeds to the step of forming a hole transport layer on the photoactive layer containing the perovskite compound (S130).

The hole transport layer may be positioned between the photoactive layer and the second electrode. The hole transport layer may allow holes generated in the photoactive layer to be easily transferred to the second electrode.

The hole transport layer is P3HT (poly[3-hexylthiophene]), MDMO-PPV (poly[2-methoxy-5-(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-dipmethoxyphenylamine)-9,9,9′-spirobi fluorine]), CuSCN, CuI, 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]), 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-cobenzothiadiazole), PEDOT (poly(3,4-ethylenedioxythiophene)), PEDOT:PSS, poly( 3,4-ethylenedioxythiophene) poly(styrenesulfonate), PTAA (poly(triarylamine)), and poly(4-butylphenyldiphenyl-amine) may be included.

Finally, the method of manufacturing a perovskite optoelectronic device according to an embodiment of the present invention includes forming a second electrode on the hole transport layer ( S140 ).

The second electrode may be an electrode commonly used in the field of solar cells. More specifically, the second electrode is gold (Au), silver (Ag), platinum (Pt), palladium (Pd), copper (Cu), aluminum (Al), carbon (C), cobalt sulfide (CoS), sulfide At least one of copper (CuS) and nickel oxide (NiO) may be included. Since the second electrode may also be formed by the method described for the first electrode, a redundant description thereof will be omitted.

Therefore, in the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention, the photoactive layer containing the perovskite compound is a composition gradient in the depth direction from the hole transport layer to the electron transport layer by a spray coating method. Long-term operation stability can be improved so that it has less than 10% degradation even when continuously operated for 1000 hours under 1-sun light soaking.

In the method of manufacturing a perovskite photoelectric device according to an embodiment of the present invention, the photoactive layer containing the perovskite compound is formed to have a composition gradient in the depth direction from the hole transport layer to the electron transport layer to form an absorption wavelength ( The absorption wavelength can be extended to 750 nm to improve light harvesting.

Hereinafter, a perovskite optoelectronic device according to an embodiment of the present invention is a perovskite photoelectric device according to an embodiment of the present invention manufactured through a method for manufacturing a perovskite photoelectric device according to an embodiment of the present invention A photoelectric device will be described.

The perovskite optoelectronic device according to the embodiment of the present invention is manufactured through the manufacturing method of the perovskite optoelectronic device according to the embodiment of the present invention, and detailed descriptions of the same components will be omitted.

The perovskite photoelectric device according to an embodiment of the present invention is spray coated on the first electrode 110 , the electron transport layer 120 formed on the first electrode 110 , and the electron transport layer 120 . ), and formed on the photoactive layer 130 containing the perovskite compound, the hole transport layer 140 and the hole transport layer 140 formed on the photoactive layer 130 containing the perovskite compound and a second electrode 150 to be

A perovskite photoelectric device according to an embodiment of the present invention has a perovskite structure in which an anode electrode is disposed on a substrate or a plannar-heterojunction structure in which a cathode electrode is disposed on a substrate. It can be implemented as a photovoltaic cell.

The perovskite optoelectronic device according to an embodiment of the present invention includes a first electrode 110, the first electrode 110 is located on a substrate, and a conductive electrode, in particular, a transparent conductive electrode to improve light transmission. desirable.

The first electrode 110 is, for example, fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), aluminum-containing zinc oxide (Al-doped Zinc Oxide, AZO) And it may include at least one of indium-doped zinc oxide (IZO).

The perovskite photoelectric device according to an embodiment of the present invention includes an electron transport layer 120 formed on a first electrode 110 , and the electron transport layer 120 includes the first electrode 110 and the photoactive layer 130 . ) can be located between The electron transport layer 120 may allow electrons generated in the photoactive layer to be easily transferred to the first electrode 110 .

The electron transport layer 120 may be formed of a TiO ₂ based material, but is not limited thereto.

The perovskite photoelectric device according to the embodiment of the present invention is formed by spray coating (orthogonal spray coating) on the electron transport layer 120, and includes a photoactive layer 130 including a perovskite compound.

When the perovskite compound is introduced into the photoactive layer 130 , the highest occupied molecular orbital (HOMO) level of the hole transport layer 140 and the lowest unoccupied molecular orbital (LUMO) level of the electron transport layer 120 are perovskite, respectively. It matches well with a valence band and a conduction band of the electron, so that electrons can be transferred to the electron transport layer 120 and holes can be transferred to the hole transport layer 140 .

Through such a mechanism, electron-hole pairs can be effectively separated into electrons and holes, and the separated electrons and holes are accumulated with an internal electric field formed by a difference in work function between the first electrode 110 and the second electrode 150 . It is collected by moving to each electrode by the difference in the concentration of charges and finally flows in the form of current through an external circuit.

The photoactive layer 130 including the perovskite compound may have a composition gradient in the depth direction from the hole transport layer 140 to the electron transport layer 120, and the photoactive layer having a composition gradient in the depth direction ( 130) of the perovskite compound may be represented by the following formula (2).

[Formula 2]

AM'X' _(3-m) X" _m

M may include at least one of Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , Cu ²⁺ , Co ²⁺ , Ni ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ and Rf ²⁺ . .

X' and X" may include at least one of F ^- , Cl ^- , Br ^- , I ^- , SCN ^- and BF ₄ ^- .

Since the perovskite photoelectric device according to an embodiment of the present invention includes a photoactive layer 130 formed by coating a first perovskite compound and then coating a second perovskite compound, the perovskite In the compound, the composition ratio of X″/M′ may be changed in the depth direction from the hole transport layer 140 to the electron transport layer 120 .

In addition, in the photoactive layer 131 including the perovskite compound in contact with the electron transport layer 120 , the concentration of the first perovskite compound is higher than the concentration of the second perovskite compound, and the hole transport layer 140 ) and the photoactive layer 132 including the perovskite compound in contact with the concentration of the second perovskite compound may be higher than that of the first perovskite compound.

According to an embodiment, the photoactive layer 131 including the perovskite compound in contact with the electron transport layer 120 may include only the first perovskite compound, or the perovskite in contact with the hole transport layer 140 . The photoactive layer 132 including the skyte compound may include only the second perovskite compound,

Therefore, electron-hole pairs can be generated in the photoactive layer including the perovskite compound in contact with the electron transport layer and the photoactive layer including the perovskite compound in contact with the hole transport layer, so that electrons and holes are separated from the photoactive layer The charge collection ability can be improved by guiding electrons and holes to move in opposite directions across to the electron transport layer and the hole transport layer.

When the photoactive layer 130 has a composition gradient in the depth direction, a band gap gradient is generated according to the composition gradient, so that the electrons and holes generated in the photoactive layer 130 reduce the loss of open-circuit voltage. Separation and migration can occur much more effectively while being visible.

In addition, at least one electric field may be formed therein in the photoactive layer 130 including the perovskite compound.

As the second perovskite compound is coated, Fermi level matching occurs at the interface between the first perovskite compound and the second perovskite compound, and through this, an additional electric field is generated inside the photoactive layer 130 Thus, the electron-hole pairs generated inside the photoactive layer are separated and moved much more effectively, so that the efficiency of the photoelectric device can be increased.

The first perovskite compound may be represented by Formula 3 below.

[Formula 3]

AM'X' _2X "

Preferably, the first perovskite compound may be CsPbI ₂ Br.

The second perovskite compound may be represented by the following formula (4).

[Formula 4]

AM'X' ₃

Preferably, the second perovskite compound may be CsPbI ₃ .

The hole transport layer 140 may be PTAA (poly(triarylamine)), but is not limited thereto.

Gold (Au) may be used as the second electrode 150 , but is not limited thereto.

Therefore, the perovskite photoelectric device according to an embodiment of the present invention is formed so that the photoactive layer containing the perovskite compound has a composition gradient in the depth direction from the hole transport layer to the electron transport layer by a spray coating method. Long-term operation stability can be improved to have less than 10% degradation even when continuously operated for 1000 hours under 1-sun light soaking.

The perovskite photoelectric device according to an embodiment of the present invention is formed so that the photoactive layer including the perovskite compound has a composition gradient in the depth direction from the hole transport layer to the electron transport layer, so that the absorption wavelength is can be extended to 750 nm to improve light harvesting.

The perovskite photoelectric device according to an embodiment of the present invention includes a photoactive layer 130 having a composition gradient in the depth direction to the electron transport layer 120, and when illuminated by sunlight, the electron transport layer 120 is in contact with it. Electron-hole pairs may be generated in the photoactive layer 131 including the rovskite compound and the photoactive layer 132 including the perovskite compound in contact with the hole transport layer 140 .

Therefore, referring to FIG. 3 , electrons and holes cross the photoactive layer 130 to the electron transport layer 120 and the hole transport layer 140 to guide the electrons and holes to move in opposite directions, thereby making it easier to collect charges. there is.

In addition, referring to FIG. 3 , the photoactive layer including the perovskite compound has a composition gradient in the depth direction from the hole transport layer to the electron transport layer, so that the composition ratio of at least two monovalent anions of the perovskite compound is It can be seen that the band structure gradient in which the band gap and the Fermi level of the photoactive layer are continuously changed is formed by continuously changing.

[Example 1]: 5 seconds (5s)

The organic substrates doped with patterned fluorine-doped tin oxide (FTO) were extensively cleaned using deionized water, acetone and isopropanol, followed by an airbrush (DH-125, Spamax). A compact 50 nm TiO ₂ (c-TiO ₂ ) solution using spray-pyrolysis deposition with a 20 mM solution of titanium diisopropoxide bis(acetylacetate) (TAA) at 450°C ) layer was formed.

1.06 g of CsBr and 2.31 g of PbI ₂ and 0.52 g of CsI and 0.92 g of PbI ₂ were completely dissolved in 100 mL of DMSO at 60° C., respectively, to prepare a CsPbI2Br precursor solution and a CsPbI3 precursor solution.

Thereafter, using a 3D printer and a defective ultrasonic stray coater (S80, CERA-TORQ, 80 kHz), 0.5M CsPbI2Br precursor solution was sprayed at a flow rate of 0.8 mL/min for 280 seconds, and then 0.25 M CsPbI ₃ precursor solution was added. A graded CsPbI _3-x Br _x perovskite thin film was formed on the c-TiO ₂ /FTO substrate by spraying at a flow rate of 0.5 mL/min for 5 seconds.

At this time, the ultrasonic spray coating process conditions were a nozzle-to-substrate distance of 5 cm, a nozzle scan rate of 10 mm/s, and a CsPbI ₂ Br precursor solution of 0.8 mL/min. It has a solution flow rate, a CsPbI ₃ precursor solution flow rate of 0.5 mL/min (flow gas: N ₂ , pressure: 7 psi), and a deposition temperature of 150°C.

After forming a graded CsPbI _3-x Br _x perovskite thin film, poly-trilamine (PTAA, EM index) hole transport materials (HTMs) were spin-coated, followed by thermal evaporation of an Au counter electrode. ) was deposited by the method.

Perovskite optoelectronic devices were fabricated in an atmospheric atmosphere under a controlled relative humidity of ∼20%.

[Example 2]: 10 seconds (10s)

It was prepared in the same manner as in Example 1, except that 0.25M CsPbI ₃ precursor solution was sprayed for 10 seconds.

[Example 3]: 15 seconds (15s)

It was prepared in the same manner as in Example 1, except that 0.25M CsPbI ₃ precursor solution was sprayed for 15 seconds.

[Example 4]: 20 seconds (20s)

It was prepared in the same manner as in Example 1, except that 0.25M CsPbI ₃ precursor solution was sprayed for 20 seconds.

4 is a cross-sectional scanning electron microscopy (SEM) image of a photoactive layer prepared by spray coating for 5 seconds (Example 1), and FIG. 5 shows a surface scanning electron microscope image.

6 is a cross-sectional scanning electron microscope image of the photoactive layer prepared by spray coating for 10 seconds (Example 2), and FIG. 7 is a surface scanning electron microscope image.

8 is a cross-sectional scanning electron microscope image of a photoactive layer prepared by spray coating for 15 seconds (Example 3), and FIG. 9 is a surface scanning electron microscope image.

10 is a cross-sectional scanning electron microscope image of a photoactive layer prepared by spray coating for 20 seconds (Example 4), and FIG. 11 is a surface scanning electron microscope image.

4, 6, 8 and 10, as the spray coating time increases, it can be seen that the thickness of the photoactive layer having a composition gradient in the depth direction increases from ~490 nm to ~500 nm.

4, 7, 9 and 11, it can be seen that the size of the average perovskite particles gradually decreases as the spray coating time increases.

12 to 21 show the characteristics of the depth profile (Depth profiles) of the photoactive layer according to the spray coating time.

12 , according to the penetration depth, the photoactive layer is CsPbI _3.00 , CsPbI _2.75 Br _0.25 , CsPbI _2.50 Br _0.05 , CsPbI _2.25 Br _0.75 and CsPbI _2.00 Br ₁ , and the composition of I and Br is changed in the depth direction. It can be seen that the composition has a gradient.

13 is a grazing incidence X-ray diffraction graph of a photoactive layer prepared by spray coating for 5 seconds (Example 1), and FIG. 14 is a graph showing spray coating for 10 seconds (Example 2). , FIG. 15 is a graph showing spray coating for 15 seconds (Example 3), and FIG. 16 is a graph showing spray coating for 20 seconds (Example 4).

13 to 16 , the (200) peak position of (200) CsPbI ₃ is 28.69°, and the (200) peak position of CsPbI ₂ Br is 29.55°, but as the grazing incidence angle increases, the (200) peak position is It can be seen that is gradually increased.

That is, as it is seen that the single (200) peak position is gradually shifted by the grazing incident angle, as the CsPbI ₃ precursor solution is spray-coated on the CsPbI ₂ Br film, CsPbI _3-x Br _x is formed. it can be seen that

In addition, as the spray coating time increased, the (200) peak position with 0.1° grazing incidence angle shifted significantly, through which the I content of CsPbI _3-x _Br _x gradually decreased near the top surface of CsPbI 3-x Br _x . can be seen to increase.

17 is a graph showing the depth profile of the (200) peak position of the photoactive layer according to the spray coating time, and FIG. 18 shows the correlation between the Br/Pb composition ratio (y) and the (200) peak position (x) It is a graph, and FIG. 19 is a graph showing compositional depth profiles of the photoactive layer according to spray coating time.

The correlation between the Br/Pb composition ratio (y) and the (200) peak position (x) may be expressed by Equation 1 below.

[Equation 1]

y=0.83x+28.071

17 to 19 , as the spray coating time increases, the inflow of CsPbI ₃ increases, and it can be seen that CsPbI _3-x Br _x rich in I is formed on the upper surface of the photoactive layer.

At this time, when spraying proceeds for 15 seconds (Example 3), it can be seen that the CsPbI ₃ layer is formed on the upper surface of CsPbI _3-x Br _x .

20 is a graph showing the depth profile of the electronic bandgap (Eg) of the photoactive layer according to the spray coating time, and FIG. 21 is the minimum conduction band (CBM) of the photoactive layer according to the spray coating time and It is a graph showing the depth profile of the maximum valence band (VBM).

20 and 21 , it can be seen that the average carrier life is increased as the spray coating time is increased from 5 seconds to 20 seconds.

More specifically, in the metal halide perovskite compound, as the content of I increases, the band gap may decrease, and the exciton binding energy may decrease, so that the emission lifetime may be increased.

Similarly, as the spray coating time increases, the amount of I increases and the emission lifetime decreases due to the decrease of the exciton binding energy. As the content of I increases, the electron-hole pairs generated in the perovskite photoactive layer become Separation occurs more easily, which may shorten the luminescence lifetime.

22 to 32 are graphs illustrating device performance characteristics of a perovskite optoelectronic device according to an embodiment of the present invention.

22 shows a scanning electron microscope image of a perovskite photoelectric device according to an embodiment of the present invention including a photoactive layer prepared by spray coating for 15 seconds (Example 3).

Referring to FIG. 22 , it can be seen that a perovskite photoelectric device (FTO/bl-TiO ₂ /graded CsPbI _3-x Br _x /PTAA/Au) according to an embodiment of the present invention is well formed.

23 is a graph showing an absorption spectrum of a perovskite photoelectric device according to an embodiment of the present invention, FIG. 24 is a graph showing an external quantum efficiency spectrum (EQE spectra), and FIG. 25 is an open It is a graph showing the voltage (Voc), Fig. 26 is a graph showing the short circuit current density (Jsc), Fig. 27 is a graph showing the charging factor (FF), and Fig. 28 is a graph showing the energy conversion efficiency (PCE) It is one graph.

Table 1 is a table showing the electrical and optical characteristics of the perovskite optoelectronic device according to an embodiment of the present invention.

[Table 1]

Referring to FIG. 23 , as the spray coating time of the CsPbI ₃ precursor solution increases, I-rich CsPbI _3-x Br _x is formed and the absorption wavelength is red-shifted.

More specifically, since the lattice size increases as X goes from Cl → Br → I in the metal halide perovskite, the absorption wavelength may gradually shift to red, which is a longer wavelength.

24 to 27 and Table 1, it can be seen that as the spray coating time increases, the open circuit voltage is decreased while the short circuit current density is improved, so that light absorption for a long wavelength is increased.

More specifically, as the spray coating time increases, the content of I increases, so that the absorption wavelength gradually increases to a longer wavelength, so that the amount of light absorption increases, thereby increasing the amount of generated current density.

In addition, the filling factor has a maximum value when spray coating is performed for 15 seconds, and as a result, it can be seen that it has an energy conversion efficiency of 14.63±1.07% under 1-sun conditions.

29 is a graph showing current density-voltage curves (JV curves) of a perovskite photoelectric device according to an embodiment of the present invention including a photoactive layer prepared by spray coating for 5 seconds (Example 1) 30 is a graph in which spray coating is performed for 10 seconds (Example 2), FIG. 31 is a graph in which spray coating is performed for 15 seconds (Example 3), and FIG. 32 is spray coating in progress for 20 seconds. (Example 4) It is a graph.

29 to 32 and Table 1, the perovskite photoelectric device according to an embodiment of the present invention including a photoactive layer prepared by spray coating for 15 seconds (Example 3) in the case of forward scan It can be seen that 16.45%, high energy conversion efficiency of 16.81% for the reverse scan and charged particles.

33 to 36 are graphs illustrating sub-modules and long-term stability characteristics of a perovskite optoelectronic device according to an embodiment of the present invention.

33 is an image showing a sub-module of a perovskite optoelectronic device according to an embodiment of the present invention, FIG. 34 is a graph showing a photocurrent-voltage (IV) curve of the sub-module, and FIG. 35 is an initial stage ( It is a graph showing the stabilized power output of the sub-module in the early stage; 0 to 60 sec. It is a graph showing the results of a long-term light-soaking stability test under (1-sun illumination), and FIG. 37 is a graph showing a photocurrent-voltage curve during a stability test for 1000 hours.

In order to confirm the long-term stability of the perovskite optoelectronic device according to an embodiment of the present invention, a large-area perovskite optoelectronic device of 8X14cm ² was prepared as shown in FIG. 33,

The western module of FIG. 33 is composed of 7 sub-cells connected in series.

Referring to FIG. 34 , it can be seen that the open circuit voltage is 7.64V, the current density is 281.12mA, and the charging factor is 13.82%.

35 to 37 , it can be seen that the sub-module of the perovskite optoelectronic device according to the embodiment of the present invention under 1-sun illumination shows a stabilized power output and has long-term stability under continuous light absorption. there is.

In addition, it can be seen that the energy conversion efficiency of the sub-module of the perovskite optoelectronic device according to the embodiment of the present invention is 12.54%, which is reduced by only ~09.3% compared to the perovskite optoelectronic device of the initial stage.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions can be made by those skilled in the art to which the present invention pertains. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the following claims as well as the claims and equivalents.

Claims

forming an electron transport layer on the first electrode;

forming a photoactive layer including a perovskite compound on the electron transport layer by spray coating (orthogonal spray coating);

forming a hole transport layer on the photoactive layer containing the perovskite compound; and

forming a second electrode on the hole transport layer;

including,

The photoactive layer comprising the perovskite compound is a method of manufacturing a perovskite photoelectric device, characterized in that it has a composition gradient (Graded) in the depth direction from the hole transport layer to the electron transport layer.
The method of claim 1,

The photoactive layer comprising the perovskite compound is a method of manufacturing a perovskite photoelectric device, characterized in that the band structure gradient is formed continuously in the depth direction from the hole transport layer to the electron transport layer.
The method of claim 1,

The photoactive layer comprising the perovskite compound is a method of manufacturing a perovskite photoelectric device, characterized in that at least one electric field is formed therein.
The method of claim 1,

The perovskite compound is a method of manufacturing a perovskite photoelectric device, characterized in that represented by the following formula (1).

[Formula 1]

AaMmXc

(In Formula 1, when A is a monovalent cation, M is a divalent or trivalent metal cation, X is a monovalent anion, and M is a divalent metal cation, a+2b=c, M is a trivalent metal For positive ions, a+3b=c, and a, b, and c are natural numbers.)
5. The method of claim 4,

The perovskite compound is a method of manufacturing a perovskite photoelectric device, characterized in that represented by the following formula (2).

[Formula 2]

AM'X' (3-m) X" m

(In Formula 2, A is a monovalent cation, M' is a divalent metal cation, X' and X" are monovalent anions, and m is 0≤m≤1.)
The method of claim 1,

The perovskite compound includes at least two or more monovalent anions, and the composition ratio of the at least two or more monovalent anions is changed in the depth direction.
The method of claim 1,

Forming a photoactive layer comprising a perovskite compound by spray coating on the electron transport layer,

coating a first perovskite compound on the electron transport layer; and

coating a second perovskite compound on the coated first perovskite compound;

A method of manufacturing a perovskite photoelectric device comprising a.
8. The method of claim 7,

In the photoactive layer comprising the perovskite compound in contact with the electron transport layer, the concentration of the first perovskite compound is higher than the concentration of the second perovskite compound,

In the photoactive layer including the perovskite compound in contact with the hole transport layer, the concentration of the second perovskite compound is higher than that of the first perovskite compound. Method of manufacturing a perovskite photoelectric device .
8. The method of claim 7,

The second coating time of the perovskite compound is a method of manufacturing a perovskite photoelectric device, characterized in that 0.5 seconds to 200 seconds.
8. The method of claim 7,

Method of manufacturing a perovskite photoelectric device, characterized in that it comprises adjusting the average diameter of the perovskite compound according to the coating time of the second perovskite compound.
8. The method of claim 7,

The first perovskite compound is represented by the following formula (3), the second perovskite compound is a method of manufacturing a method of manufacturing a perovskite photoelectric device, characterized in that represented by the following formula (4).

[Formula 3]

AM'X' 2X "

[Formula 4]

AM'X' 3

(In Formulas 3 and 4, A is a monovalent cation, M' is a divalent metal cation, and X' and X" are monovalent anions.)
a first electrode;

an electron transport layer formed on the first electrode;

a photoactive layer formed by orthogonal spray coating on the electron transport layer and including a perovskite compound;

a hole transport layer formed on the photoactive layer including the perovskite compound; and

and a second electrode formed on the hole transport layer,

The photoactive layer comprising the perovskite compound is a perovskite photoelectric device, characterized in that it has a composition gradient in the depth direction from the hole transport layer to the electron transport layer.
13. The method of claim 12,

The photoactive layer including the perovskite compound is a perovskite photoelectric device, characterized in that the band structure gradient is formed continuously in the depth direction from the hole transport layer to the electron transport layer.
13. The method of claim 12,

The photoactive layer comprising the perovskite compound is a perovskite photoelectric device, characterized in that at least one electric field is formed therein.
13. The method of claim 12,

The photoactive layer is a perovskite compound is a perovskite photoelectric device, characterized in that represented by the following formula (1).

[Formula 1]

AaMmXc

(In Formula 1, when A is a monovalent cation, M is a divalent or trivalent metal cation, X is a monovalent anion, and M is a divalent metal cation, a+2b=c, M is a trivalent metal For positive ions, a+3b=c, and a, b, and c are natural numbers.)
16. The method of claim 15,

The photoactive layer is a perovskite compound is a perovskite photoelectric device, characterized in that represented by the following formula (2).

[Formula 2]

AM'X' (3-m) X" m

(In Formula 2, A is a monovalent cation, M' is a divalent metal cation, X' and X" are monovalent anions, and m is 0≤m≤1.)
13. The method of claim 12,

The perovskite compound includes at least two or more monovalent anions, and a perovskite photoelectric device, characterized in that the composition ratio of the at least two or more monovalent anions is changed in the depth direction.
13. The method of claim 12,

The photoactive layer comprising the perovskite compound comprises a first perovskite compound and a second perovskite compound,

In the photoactive layer comprising the perovskite compound in contact with the electron transport layer, the concentration of the first perovskite compound is higher than the concentration of the second perovskite compound,

The photoactive layer including the perovskite compound in contact with the hole transport layer is a perovskite photoelectric device, characterized in that the concentration of the second perovskite compound is higher than that of the first perovskite compound.