KR20210108216A - Manufacturing method of perovskite compound improving color purity and perovskite optoelectric device including the same - Google Patents

Abstract

Disclosed are a method for preparing a perovskite compound and a perovskite photoelectric device comprising the same. A method for preparing a perovskite compound according to an embodiment of the present invention comprises the steps of: preparing a metal halide-ligand solution containing a divalent or trivalent metal cation and a monovalent anion; and preparing a perovskite compound, represented by the following chemical formula, by mixing the metal halide-ligand solution, a metal oleate solution containing a monovalent metal cation, and a halogen donor, wherein the halogen donor is a solution containing a halogen anion: [Formula] ABX_3 (where A is a monovalent metal cation, B is a divalent metal cation, and X is a monovalent anion).

Description

Manufacturing method of a perovskite compound with improved color purity and a perovskite photoelectric device comprising the same

The present invention relates to a method for preparing a perovskite compound having improved color purity and a perovskite photoelectric device comprising the same.

Metal halide perovskite solar cells have been developed to have the same photoelectric conversion efficiency as commercial solar cells.

This is because perovskite materials have suitable photovoltaic properties such as high absorption coefficient due to direct bandgap, long diffusion length of charge carriers due to long lifetime, high open circuit voltage due to small exciton binding energy, and low temperature solution processability. am.

Due to these properties, nano-sized perovskite is a very attractive material for optoelectronic devices.

In particular, perovskite materials can physically confine excitons within nanoscale crystals, overcoming the small exciton binding energies that are problematic for LED fabrication.

Therefore, perovskite nanocrystals are ideal for demonstrating full-color LEDs with high color purity.

In addition, compared to commercial LEDs such as OLEDs and QDLEDs, perovskite nanocrystal (PNC)-based LEDs are less expensive than OLEDs because of shorter process steps and cheaper materials.

In addition, PNC-based LEDs allow easier control of their electrical properties than QDLEDs because fine and uniform crystal size control is not required.

Currently, many experimental procedures for synthesizing metal halide perovskite nanocrystals have been reported.

Among the proposed methods, the hot-injection method is a PbX ₂ (X=Cl, Br, I) salt, oleic acid, and oleylamine ^{acting as Pb 2+} and X ^{− sources in octadecene (ODE).} _{CsPbX 3} Perovskite nanocrystals were obtained by injecting Cs-oleate into a high-temperature solution (140-200° C.) prepared by dissolution.

However, the method by CsPbX ₃ perovskite PbX ₂ to synthesize a nanocrystal, fills the insufficient halide portion using PbX ₂ in an excess amount does not react to control so as to adjust the band gap by mixing PbX ₂ salt There was a problem that impurities were generated.

Korean Patent Publication No. 10-1815588, "Perovskite nanocrystal particles and optoelectronic devices using the same" Korean Patent Publication No. 10-1158985, "Method for producing perovskite compound powder"

An embodiment of the present invention is a method for preparing a perovskite compound capable of preparing nano-sized perovskite compound crystals with reduced impurities by filling the insufficient halogen composition using a halogen donor when preparing the perovskite compound would like to provide

An embodiment of the present invention is to provide a method for preparing a perovskite compound capable of performing a uniform halogen substitution reaction using a halogen donor when preparing the perovskite compound.

An embodiment of the present invention is to provide a method for producing a perovskite compound prepared by using a halogen donor is a perovskite compound in which the halogen anion is uniformly substituted to have a narrow line width.

An embodiment of the present invention is to provide a method for preparing a perovskite compound capable of preparing a perovskite compound having reduced impurities at a lower temperature than before using a halogen donor when preparing the perovskite compound.

An embodiment of the present invention is to provide a perovskite photoelectric device having a long PL lifetime and high color purity, including a perovskite compound with few impurities and a narrow line width.

The method for preparing a perovskite compound according to the present invention comprises the steps of: preparing a metal halide-ligand solution containing a divalent or trivalent metal cation and a monovalent anion; and mixing the metal halide-ligand solution, a metal oleate solution containing a monovalent metal cation, and a halogen donor to prepare a perovskite compound represented by the following formula, wherein the halogen donor produces a halogen anion It is characterized in that it is a solution containing

[Formula]

A _a B _b X _c

(Where A is a monovalent metal cation, B is a divalent or trivalent metal cation, and X is a monovalent anion.)

a+2b=c (a,b,c are natural numbers) or a+3b=4c (a,b,c are natural numbers)

According to the method for producing a perovskite compound according to an embodiment of the present invention, the halogen donor may react with the metal oleate solution to form a metal halide.

According to the method for producing a perovskite compound according to an embodiment of the present invention, the halogen donor may generate crystal nuclei of the perovskite compound.

According to the method for producing a perovskite compound according to an embodiment of the present invention, the perovskite compound is a nano-sized nanorod, a nanoplate, a nanocube, and a nanowire cube ( cube) may have at least one shape selected from the group consisting of, and the perovskite compound is orthorhombic, cubic, tetragonal, dimer or layered (layer) It may have a structure or a structure in which two or more of these structures are mixed.

According to the method for producing a perovskite compound according to an embodiment of the present invention, the crystal size of the perovskite compound may be 1 nm to 100 nm.

According to the method for producing a perovskite compound according to an embodiment of the present invention, the halogen donor and the divalent or trivalent metal cation contained in the metal halide-ligand solution are in a molar ratio of 1:1 to 10:1. may include

According to the method for producing a perovskite compound according to an embodiment of the present invention, X may include different halogen anions from each other by a halogen substitution reaction.

According to the method for producing a perovskite compound according to an embodiment of the present invention, the perovskite compound includes a metal impurity formed by the divalent or trivalent metal cation, or the monovalent anion, and the metal Impurities may be included in an amount of 10% by weight or less based on the total weight of the perovskite compound.

According to the method for producing a perovskite compound according to an embodiment of the present invention, the perovskite compound may be prepared at 20 °C to 150 °C.

The perovskite photoelectric device according to the present invention may include a perovskite compound prepared according to the method for preparing the perovskite compound.

According to the perovskite photoelectric device according to an embodiment of the present invention, the perovskite compound includes different halogen anions, and the perovskite photoelectric device according to the exciton binding energy of the perovskite compound line width can be adjusted.

According to the perovskite photoelectric device according to an embodiment of the present invention, the PLQY (photoluminescence quantum yield) of the perovskite photoelectric device may be 70% to 100%.

According to the perovskite optoelectronic device according to an embodiment of the present invention, the PL (photoluminescence) line width (full width at half maximum) of the perovskite photoelectric device is 10 nm at room temperature (20 ℃) to 30 nm.

According to the perovskite optoelectronic device according to the embodiment of the present invention, the EL (electroluminescence) line width of the perovskite photoelectric device may be 15 nm to 40 nm.

According to the perovskite photoelectric device according to the embodiment of the present invention, the PL (photoluminescence) wavelength of the perovskite photoelectric device may be 350nm to 1200nm.

According to an embodiment of the present invention, when the perovskite compound is prepared, a nano-sized perovskite compound crystal having reduced impurities can be prepared by filling the insufficient halogen composition using a halogen donor.

According to an embodiment of the present invention, a uniform halogen substitution reaction may be performed using a halogen donor when preparing the perovskite compound.

According to an embodiment of the present invention, in the perovskite compound prepared using a halogen donor, halogen anions are uniformly substituted, so that the line width may be narrowed.

According to an embodiment of the present invention, a perovskite compound having reduced impurities can be prepared at a lower temperature than in the prior art by using a halogen donor when preparing the perovskite compound.

According to an embodiment of the present invention, it is possible to manufacture a perovskite optoelectronic device having a long PL lifetime and high color purity by including a perovskite compound with few impurities and a narrow line width.

1A to 1C are transmission electron microscopy (TEM) images and high-resolution transmission electron microscopy (HR-TEM) images showing the appearance of a perovskite compound according to an embodiment of the present invention.
Figure 2 is a graph showing the PLQY (PL quantum yield) of the perovskite compound according to an embodiment of the present invention.
3A and 3B are graphs showing PL (photoluminescence) spectra of the perovskite compounds of Comparative Examples and Examples, and FIGS. 3C and 3D are the line width and PL spectrum peaks of the perovskite compounds of Comparative Examples and Examples. It is a graph showing the position.
4 is a graph showing luminance versus voltage of a perovskite photoelectric device according to an embodiment of the present invention.
5 is a graph showing the EL (electroluminescence) intensity of a perovskite photoelectric device according to an embodiment of the present invention.
6 is a graph illustrating external quantum efficiency of a perovskite photoelectric device according to an embodiment of the present invention.
7 is a graph showing color coordinates of a perovskite photoelectric device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the 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. As used herein, 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 steps mentioned.

As used herein, “embodiment”, “example”, “aspect”, “exemplary”, etc. are to be construed as advantageous in which any aspect or design described is preferred or advantageous over other aspects or designs. it 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 one 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 are 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 understood as limiting the technical idea, but should be understood as exemplary 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, not 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. And, the terms (terminology) used in this specification are terms used to properly express the embodiment of the present invention, which may vary according to the intention of the 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 for producing a perovskite compound according to an embodiment of the present invention comprises the steps of preparing a metal halide-ligand solution containing a divalent or trivalent metal cation and a monovalent anion (S110), the metal halide-ligand solution, and mixing a metal oleate solution containing a monovalent metal cation and a halogen donor to prepare a perovskite compound represented by the following Chemical Formula 1 (S120).

[Formula 1]

A _a B _b X _c

(Where A is a monovalent metal cation, B is a divalent or trivalent metal cation, and X is a monovalent anion.)

a + 2b = c (a,b,c are natural numbers) or a + 3b = 4c (a, b,c are natural numbers)

Meanwhile, when B of the compound represented by Formula 1 is a trivalent cation, it may be represented by any one of Formulas 1-1 to 1-3 below satisfying a + 3b = 4c.

[Formula 1-1]

AMX ₃

[Formula 1-2]

AM ₂ X ₇

[Formula 1-3]

A ₃ M ₂ X ₉

In Formulas 1-1 to 1-3, A is a monovalent cation, M is a trivalent cation, and X is a monovalent anion.

The metal halide-ligand solution contains a divalent or trivalent metal cation, a monovalent anion, and a ligand, and a divalent or trivalent metal cation and monovalent contained in the perovskite compound prepared in step S120 to be described later It may be a precursor solution that provides anions.

The monovalent metal cation is alkylammonium, formamidinium, guanidinium, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Fr ⁺ , Cu(I) ⁺ , Ag(I) ⁺ and Au ( I) ^{may include any one of +} , but is not limited thereto.

The divalent metal cation includes any one of Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , Cu ²⁺ , Co ²⁺ , Ni ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ and Rf ²⁺ . can, but is not limited thereto.

The trivalent metal cation may ^{include any one of Sb 3+} , Bi ³⁺ and In ³⁺ , but is not limited thereto.

The monovalent anion may include any one of halogen ions (F-, Br-, Cl-, I-), SCN-, PF6-, and BF4-, but is not limited thereto.

The monovalent anion may include any one of halogen anions including ^{F −} , Cl ⁻ , Br ⁻ and I ⁻ _{, BF 4} ⁻ , PF ₆ ⁻ and SCN ⁻ , but is not limited thereto.

The ligand may include at least one of oleylamine (OLAm) and oleic acid (OA), but is not limited thereto.

For example, the metal halide-ligand solution may include Pb ^{2+ as a divalent metal cation, Br −} as a monovalent anion, OLAm and OA as the ligand, and thus (OLAm)PbBr ₂ (OA) may include

In step S120, the perovskite compound represented by Chemical Formula 2 below may be prepared by mixing the metal halide-ligand solution, a metal oleate solution containing a monovalent metal cation, and a halogen donor.

[Formula 2]

ABX ₃

Here, A is a monovalent metal cation included in the metal oleate solution, B is a divalent metal cation included in the metal halide-ligand solution, and X is a monovalent anion or halogen included in the metal halide-ligand solution It is a halogen anion contained in the donor.

In this case, the halogen donor is a solution containing a halogen anion, and the halogen anion may include any one ^{of F -} , Cl ^- , Br ^- and I ^-.

According to an embodiment, the halogen donor may be an alkyl group having 1 to 20 carbon atoms or a solution in which hydrogen (H) is ionically bonded to a halogen anion. For example, the halogen donor may be HBr.

The metal oleate solution may be prepared by mixing a precursor containing a monovalent metal cation and oleic acid.

The monovalent metal cation may be Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Fr ⁺ , Cu(I) ⁺ , Ag(I) ⁺ , Au(I) ⁺ or a combination thereof. It is not limited to the material.

For example, the metal oleate solution _{may be prepared by mixing Cs 2} CO ₃ ^{(cesium carbonate) containing Cs +} , which is a monovalent metal cation, and oleic acid, and thus Cs-OA may be included.

The halogen donor may react with the metal oleate solution to form a metal halide.

Specifically, a halogen anion included in the halogen donor and a monovalent metal cation included in the metal oleate solution may react to form a metal halide.

^{For example, Cs +} contained in the metal oleate solution ^{may react with Br −} of the halogen donor to form CsBr.

The halogen donor reacts with the metal oleate solution to form a metal halide, and reacts with a divalent or trivalent metal cation and monovalent anion contained in the metal halide-ligand solution to form a crystal nucleus of the perovskite compound can be formed In this case, the final product of the perovskite compound can be synthesized while the formed crystal nuclei undergo crystal growth.

According to an embodiment, the halogen donor may include a halogen anion that is the same as or different from the monovalent anion contained in the metal halide-ligand solution.

When the halogen anion included in the halogen donor is the same as the monovalent anion included in the metal halide-ligand solution, the halogen donor generates crystal nuclei of the perovskite compound, resulting in nano-sized cube crystals A perovskite compound crystal having a structural phase can be prepared.

The perovskite compound may have at least one shape selected from the group consisting of a nano-sized nanorod, a nanoplate, a nanocube, and a nanowire cube, The lobskite compound may have an orthorhombic, cubic, tetragonal, dimer or layer structure, or a structure in which two or more of these structures are mixed. .

For example, when the metal halide-ligand solution includes (OLAm)PbBr ₂ (OA) and the halogen donor ^{includes Br −} , the halogen donor generates crystal nuclei of the perovskite compound, CsPbBr ₃ crystalline compounds can be prepared.

When the halogen anion contained in the halogen donor is the same as the monovalent anion contained in the metal halide-ligand solution, it is better than the perovskite compound prepared by the conventional hot-injection method by filling the insufficient halogen composition. It may contain a small amount of metallic impurities.

The metal impurity is a material in which divalent or trivalent metal cations and monovalent anions contained in the metal halide-ligand solution in step S120 have not reacted with the halogen donor and the metal oleate solution. It may cause PL quenching of the compound.

For example, when the metal halide-ligand solution is (OLAm)PbBr ₂ (OA), PbBr ₂ does not react with the halogen donor and the metal oleate solution, so that Pb or PbBr _{2 is added to the perovskite compound.} may be present as metal impurities.

However, the halogen donor fills the insufficient halogen composition when generating the crystal of the perovskite compound so that the divalent or trivalent metal cation and monovalent anion contained in the metal halide-ligand solution can react sufficiently. , the perovskite compound may contain less metal impurities than in the prior art.

When the halogen anion contained in the halogen donor is different from the monovalent anion contained in the metal halide-ligand solution, the halogen anion and the monovalent anion may be uniformly substituted by a halogen substitution reaction.

For example, when the metal halide-ligand solution includes (OLAm)PbBr ₂ (OA) and the halogen donor ^{includes I −} , a halogen substitution reaction as shown in the following reaction scheme may occur.

[reaction formula]

PbBr ₂ +HI→PbBr _2-x I _x (where 0<x<3)

Halogen-substituted PbBr _2-x I _x reacts with a metal oleate solution to prepare a perovskite compound including two different halogen anions at the X site.

According to the halogen substitution reaction, the perovskite compound may emit a color including blue, red, or green, and the monovalent anion and the halogen anion can be uniformly substituted by using the halogen donor. It is possible to reduce the line width of the lobskite compound.

In addition, in the perovskite compound including different halogen anions at the X site, the exciton binding energy is reduced compared to the case where the X site contains a single halogen anion, so that the PL intensity is reduced, and the line width ( full width at half maximum (fwhm) can be narrow.

On the other hand, the exciton binding energy is inversely proportional to the square of the permittivity, and is proportional to the effective mass. The halogen element has a value of Cl<Br<I in the case of dielectric constant and Cl>Br>I in the case of effective mass, and the exciton binding energy shows a tendency of Cl>Br>I. In addition, the PL line width is widened in the order of Cl < Br < I, and the PL strength increases as the binding energy of the same material increases.

Accordingly, in step S120, the metal halide-ligand solution and the metal oleate solution are mixed with halogen donors including different halogen anions to prepare a perovskite compound with a narrow line width and almost no metal impurities. can

In step S120, the exciton binding energy of the perovskite compound may be adjusted by adjusting the molar ratio of the halogen donor to the divalent or trivalent metal cation contained in the metal halide-ligand solution.

Specifically, in step S120, the halogen donor and the metal halide are included in a molar ratio of 1:1 to 10:1 between the halogen donor and the (divalent or trivalent) metal cation contained in the metal halide-ligand solution. -Can mix ligand solutions. The molar ratio of 1:1 is the minimum value according to the stoichiometry, and when it exceeds 10:1, the amount of distilled water (DI water), which is a solvent of the halogen donor, increases, and the resulting perovskite compound may be decomposed by the distilled water. More preferably, the metal cation contained in the metal halide-ligand solution may be in a molar ratio of 1:1 to 3:1, and even more preferably, the halogen donor and the metal are included in a molar ratio of 3:1. The halide-ligand solution may be mixed. However, when using a halogen donor (R-X or H-X) in a gas phase that does not use distilled water as a solvent, the molar ratio is not limited.

The crystal size of the perovskite compound may be 1 nm to 100 nm.

The method for producing a perovskite compound according to an embodiment of the present invention can produce a perovskite compound having a small content of metal impurities and a narrow line width at a lower temperature than the conventional hot injection method performed at 140° C. to 200° C. have.

Specifically, the method for preparing a perovskite compound according to an embodiment of the present invention can prepare the perovskite compound at 20 °C to 150 °C.

In summary, the method for producing a perovskite compound according to an embodiment of the present invention fills the insufficient halogen composition by adding more halogen donors during the production of the perovskite compound, so that uniform halogen substitution is possible, and metal impurities are less than conventional ones. It is possible to prepare nano-sized perovskite compound crystals with high purity even at room temperature by remarkably reduced.

In addition, different halogen anions may be included in the perovskite compound through a halogen substitution reaction using a halogen donor of the perovskite compound according to an embodiment of the present invention, and exciton binding energy only through the process of adding a halogen donor can reduce the line width compared to the prior art.

Hereinafter, a perovskite photoelectric device including a perovskite compound prepared by the method for preparing a perovskite compound according to an embodiment of the present invention will be described.

Since the perovskite compound included in the perovskite optoelectronic device includes the components of the above-described method for preparing the perovskite compound, a redundant description thereof will be omitted.

The perovskite optoelectronic device of the present invention may include a first electrode, an electron transport layer, a photoactive layer, a hole transport layer, and a second electrode.

The first electrode may be formed on a substrate, and the substrate may be an organic substrate or an inorganic substrate.

The inorganic substrate may include glass, quartz, Al ₂ O ₃ , SiC, Si, GaAs, or InP, but is not limited thereto.

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 be selected from propionate (cellulose acetate propionate, CAP), but is not limited thereto.

The inorganic substrate and the organic substrate are preferably made of a transparent material through which light is transmitted, and when the substrate is an organic substrate, flexibility of the perovskite photoelectric device can be increased.

The first electrode is formed on the substrate and may serve as an anode when the perovskite optoelectronic device has an inverted structure.

For example, the first electrode contains fluorine doped tin oxide (FTO), indium doped tin oxide (ITO), aluminum-doped zinc oxide (AZO), and indium. It may be selected from the group consisting of zinc oxide (Indium doped Zinc Oxide, IZO) or a mixture thereof, but is not limited thereto.

Preferably, the first electrode may include ITO, which is a transparent electrode having a large work function to facilitate injection of holes into the highest occupied molecular orbital (HOMO) level of the photoactive layer.

The first electrode is formed on a substrate by thermal evaporation, e-beam evaporation, radio frequency sputtering, magnetron sputtering, vacuum deposition, or chemical vapor deposition. vapor deposition) may be formed by any one method.

In addition, the first electrode may include a transparent conductive electrode having an OMO (O=organic, metal oxide, M=metal) structure.

According to an embodiment, the first electrode may have a sheet resistance of 1Ω/cm ² to 1000Ω/cm ² , and a transmittance of 80% to 99.9%.

In the case the surface resistance of the first electrode 1Ω / cm ² is less than if the transmittance is lowered it is difficult to use a transparent electrode, 1000Ω / cm ² than if there is a disadvantage that high resistance perovskite degraded performance of the photoelectric device.

In addition, when the transmittance of the first electrode is less than 80%, light extraction or light transmission is low, so that the performance of the perovskite optoelectronic device is deteriorated.

The electron transport layer is formed between the first electrode and the photoactive layer, so that electrons can be easily transferred between the photoactive layer and the first electrode.

When a perovskite photoelectric device is used as a light emitting device, the electron transport layer can move electrons injected from the second electrode to the photoactive layer, and when the perovskite photoelectric device is used as a solar cell, in the photoactive layer The generated electrons may be easily transferred to the first electrode.

According to an embodiment, the electron transport layer may include fullerene (C60), a fullerene derivative, perylene, or TPBi(2,2',2"-(1,3,5-benzinetriyl)-tris(1-phenyl-) 1-H-benzimidazole)), polybenzimidazole (PBI) and PTCBI (3,4,9,10-perylene-tetracarboxylic bis-benzimidazole), Naphthalene diimide (NDI) and their derivatives, TiO ₂ , SnO ₂ , ZnO, ZnSnO ₃ , 2,4,6-Tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine, 8-Hydroxyquinolinolato-lithium, 1,3,5-Tris(1-phenyl-1Hbenzimidazol- 2-yl)benzene, 6,6'-Bis[5-(biphenyl-4-yl)-1,3,4-oxadiazo-2-yl]-2,2'-bipyridyl, 4,4'-Bis( 4,6-diphenyl-1,3,5-triazin-2-yl)biphenyl (BTB), Rb ₂ CO ₃ (Rubidium carbonate), ReO ₃ (Rhenium (VI) oxide) may include at least one .

The fullerene derivative may be PCBM ((6,6)-phenyl-C61-butyric acid-methylester) or PCBCR ((6,6)-phenyl-C61-butyric acid cholesteryl ester). no.

According to an embodiment, when the perovskite photoelectric device has an inverted structure, a TiO ₂ based or Al ₂ O ₃ based porous material may be mainly used as the electron transport layer.

The photoactive layer includes the perovskite compound prepared by the above-described method for preparing the perovskite compound, and redundant description will be omitted.

The perovskite compound may be represented by the following formula (1), preferably it may be represented by the following formula (2).

[Formula 1]

A _a B _b X _c

(Where A is a monovalent metal cation, B is a divalent or trivalent metal cation, and X is a monovalent anion.)

a + 2b = c (a,b,c are natural numbers) or a + 3b = 4c (a, b,c are natural numbers)

[Formula 2]

ABX ₃

Here, A is a monovalent metal cation, B is a divalent metal cation, and X is a monovalent anion.

Meanwhile, when B of the compound represented by Formula 1 is a trivalent cation, it may be represented by any one of Formulas 1-1 to 1-3 below satisfying a + 3b = 4c.

[Formula 1-1]

AMX ₃

[Formula 1-2]

AM ₂ X ₇

[Formula 1-3]

A ₃ M ₂ X ₉

In Formulas 1-1 to 1-3, A is a monovalent cation, M is a trivalent cation, and X is a monovalent anion.

The metal halide-ligand solution contains a divalent or trivalent metal cation, a monovalent anion, and a ligand, and a divalent or trivalent metal cation and monovalent contained in the perovskite compound prepared in step S120 to be described later It may be a precursor solution that provides anions.

The monovalent metal cation is alkylammonium, formamidinium, guanidinium, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Fr ⁺ , Cu(I) ⁺ , Ag(I) ⁺ and Au ( I) ^{may include any one of +} , but is not limited thereto.

The divalent metal cation includes any one of Pb ²⁺ , Sn ²⁺ , Ge ²⁺ , Cu ²⁺ , Co ²⁺ , Ni ²⁺ , Ti ²⁺ , Zr ²⁺ , Hf ²⁺ and Rf ²⁺ . can, but is not limited thereto.

The trivalent metal cation may ^{include any one of Sb 3+} , Bi ³⁺ and In ³⁺ , but is not limited thereto.

The monovalent anion may include any one of halogen ions (F ^- , Br ^- , Cl ^- , I ^- ), SCN ^- , PF ₆ ^-, and BF ₄ ^- , but is not limited thereto.

The monovalent anion may include any one of halogen anions including ^{F −} , Cl ⁻ , Br ⁻ and I ⁻ _{, BF 4} ⁻ , PF ₆ ⁻ and SCN ⁻ , but is not limited thereto.

The ligand may include at least one of oleylamine (OLAm) and oleic acid (OA), but is not limited thereto.

For example, the metal halide-ligand solution may include Pb ^{2+ as a divalent metal cation, Br −} as a monovalent anion, OLAm and OA as the ligand, and thus (OLAm)PbBr ₂ (OA) may include

In some embodiments, X may include a single halogen anion or different halogen anions.

For example, the perovskite compound may be CsPbBr ₃ or CsPbBr _3-x I _x .

When X of the perovskite compound includes different halogen anions, the line width of the perovskite photoelectric device may be adjusted according to the exciton binding energy of the perovskite compound.

Specifically, when X of the perovskite compound includes different halogen anions, the exciton binding energy of the perovskite compound decreases, and thus perovskite photoelectric cells including the perovskite compound The line width of the device may be narrowed.

The hole transport layer is formed on the photoactive layer, and when a perovskite photoelectric device is used as a light emitting device, it serves to move the holes injected from the second electrode to the photoactive layer, and the perovskite photoelectric device is a solar cell When used as a , it is possible to easily transfer the holes generated in the photoactive layer to the second electrode.

For example, 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([2,2',7,7'-tetrkis(N,N-dipmethoxyphenylamine)-9,9'-spirobifluorine]), CuSCN, CuI, MoO _x , VO _x , NiO _x , CuO _x , 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-t hienyl-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)), poly(4-butylphenyldiphenyl-amine), 4,4'-bis[N-( 1-naphtyl)-N-phenylamino]-biphenyl (NPD), PEDOT: PSS bis (N- (1-naphthyl-n-phenyl)) benzidine (α-NPD) mixed with PFI (perfluorinated ionomer), N, N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1, 1'-diphenyl-4,4'-diamine (TPD), copper phthalocyanine (CuPc), 4,4',4"-tris(3-methylphenylamino)triphenylamine (m-MTDATA), 4,4',4"-tris(3-methylphenylamino)phenoxybenzene (m-MTDAPB), starburst type amines 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA), At least one may be selected from 4,4',4"-tris(N-(2-naphthyl)-N-phenylamino)-triphenylamine (2-TNATA) and copolymers thereof, is not limited to

The second electrode is formed on the hole transport layer and may serve as a cathode when the perovskite photoelectric device has an inverted structure.

For example, the second electrode may be lithium fluoride/aluminum (LiF/Al), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), copper (Cu), aluminum (Al), or carbon. (C), cobalt sulfide (CoS), copper sulfide (CuS), nickel oxide (NiO), or a mixture thereof, but is not limited thereto.

Since the second electrode may be formed by the same method as the method described for the first electrode, a redundant description thereof will be omitted.

The second electrode has a low work function to facilitate injection of holes into the highest occupied molecular orbital (HOMO) level of the photoactive layer, and a metal electrode having excellent internal reflectance may be used.

The perovskite photoelectric device according to the embodiment of the present invention may be any one of a light emitting device, a photo detector, an X-ray detector, and a solar cell capable of expressing RGB colors through the photoactive layer.

PL (photoluminescence) line width (full width at half maximum (fwhm)) of the perovskite photoelectric device according to an embodiment of the present invention may be 10 nm to 30 nm at room temperature (20 ° C), preferably 15 nm to 20 nm.

In addition, the EL (electroluminescence) line width of the perovskite photoelectric device according to an embodiment of the present invention may be 15 nm to 40 nm, preferably 22 nm to 30 nm.

The perovskite optoelectronic device according to an embodiment of the present invention may have a narrow line width and excellent PL lifetime by using a perovskite compound containing different monovalent anions while having a small amount of metal impurities.

In addition, the perovskite photoelectric device according to an embodiment of the present invention may include a perovskite compound having a small amount of metal impurities, thereby exhibiting excellent color purity.

Specifically, the photoluminescence quantum yield (PLQY) of the perovskite photoelectric device according to an embodiment of the present invention may be 70% to 100%, preferably 70% to 95%.

In addition, the PL (photoluminescence) wavelength of the perovskite photoelectric device according to an embodiment of the present invention may be 350 nm to 1200 nm, preferably 420 nm to 670 nm.

Hereinafter, a perovskite compound and a perovskite optoelectronic device including the same were prepared according to Examples and Comparative Examples, and then optical properties and device properties were evaluated.

1. Preparation of perovskite compounds

[Example 1]

_{(OLAm)PbBr 2} (OA) solution was prepared by mixing and stirring 8 mL of oleylamine (OLAm), 6 mL of oleic acid (OA), and 0.734 g of PbBr2 in 6 mL of toluene at 80°C.

Then, 7 mL of toluene, 3 mL of oleic acid (OA), and 0.326 g of Cs2CO3 were stirred at 80° C. until transparent to prepare a Cs(OA) solution.

Then, 20 mL of toluene and 2 mL of (OLAm)PbBr ₂ (OA) solution were mixed and stirred in an oil bath at 60 to 65 ° C., and at the same time, 1 mL of Cs(OA) solution, 69 ul of HBr as a halogen donor was added dropwise. While stirring for a total of 5 minutes (min), CsPbBr3 perovskite compound nanocrystals were prepared.

At this time, _{the molar ratio of HBr and PbBr 2} was 3:1.

Thereafter, the mixed solution was cooled to room temperature, and root particles were filtered using centrifugation to obtain _{pure CsPbBr 3 perovskite compound nanocrystals.}

[Comparative Example 1]

A perovskite compound was prepared in the same manner as in [Example 1], except that the molar ratio of HBr and PbBr _{2 was 2:1.}

[Comparative Example 2]

A perovskite compound was prepared in the same manner as in [Example 1], except that the molar ratio of HBr and PbBr _{2 was 1:1.}

[Example 2]

A perovskite compound was prepared in the same manner as in [Example 1], except that 54ul of HI was added dropwise with 23ul of HBr as a halogen donor to prepare CsPbBr _3-x I _{x perovskite compound nanocrystals.} did

[Comparative Example 3]

40 mL of octadecene (ODE), 2.5 mL of oleic acid, and _{0.814 g of Cs 2} CO ₃ were mixed and stirred at 150 ° C. in a nitrogen (N ₂ ) atmosphere until transparent to obtain a Cs (OA) solution. prepared. And, octadecene oleyl amine in 5 mL (Oleylamine) 0.5 mL, oleic acid 0.5 mL, PbI ₂ 0.058 g, PbBr ₂ to 0.023 by mixing g stirring until completely dissolved at 120 ℃, a nitrogen atmosphere, a metal halide-ligand A solution was prepared.

After that, the metal halide-ligand solution was heated to 160 °C, and 0.4 mL of the prepared Cs(OA) was injected and stirred for about 30 seconds (s) to form CsPbBr _3-x I _x perovskite compound nanocrystals. prepared.

Then, the prepared CsPbBr _3-x I _x perovskite compound nanocrystal solution was cooled with ice water. Then, the _{precipitate was collected by centrifugation to obtain pure CsPbBr 3-x} I _x perovskite compound nanocrystals, and then redispersed in toluene.

2. Fabrication of perovskite optoelectronic devices

[Example 3]

PEDOT:PSS:PFI was spin-coated on the washed ITO substrate (Hanalin Tech Co., Ltd.) at 3000 rpm for 60 seconds to form a hole injection layer.

Thereafter, the solution containing [Example 1] was spin-coated at 1500 rpm for 90 seconds on a PEDOT:PSS:PFI/ITO substrate to form a perovskite nanocrystal layer (PNC layer).

Thereafter, an electron injection layer was formed by depositing TPBi and LiF, and then an Al electrode was deposited to prepare an RGB color perovskite light emitting device.

The above Examples and Comparative Examples are summarized in the following table according to the mixing molar ratio of the perovskite compound and the sample used.

[graph]

1A to 1C are transmission electron microscopy (TEM) images and high-resolution transmission electron microscopy (HR-TEM) images showing the appearance of perovskite compounds for Comparative Examples and Examples.

1a and 1b are TEM images and HR-TEM images showing the appearance of the perovskite compound for Comparative Example 2 and Comparative Example 1, respectively, and FIG. 1c is the perovskite compound for Example 1 TEM image and HR-TEM image showing the appearance of

1A to 1C , it can be seen that all of the perovskite compounds of Example 1, Comparative Example 1, and Comparative Example 2 have nano-sized cubic crystal structures.

Referring to the HR-TEM images inserted in FIGS. 1A and 1B , in _{Comparative Example 2 and Comparative Example 1, wherein the molar ratios of HBr and PbBr 2} are 2:1 and 1:1, respectively, metallic impurities represented by black dots You can check what is included.

On the other hand, referring to the HR-TEM image inserted in FIG. 1c , in _{Example 1, in which the molar ratio of HBr and PbBr 2} is 3:1, the black dots appear blurry than those of Comparative Examples 1 and 2, so it is relatively It can be seen that the metal impurities are small.

Accordingly, the present invention can reduce the metal impurity content in the perovskite compound by preparing a crystal of the perovskite compound using a halogen donor.

Figure 2 is a graph showing the PLQY (PL quantum yield) of the perovskite compound according to an embodiment of the present invention.

In this case, HBr x1 described in FIG. 2 is the perovskite compound of Comparative Example 2, HBr x2 is the perovskite compound of Comparative Example 1, and HBr x3 is the perovskite compound of Example 1 .

2, the PLQY of Comparative Example 2 in which the molar ratio of HBr and PbBr ₂ is 1:1 is 72%, the PLQY of Comparative Example 1 in which the _{molar ratio of HBr and PbBr 2} is 2:1 is 87%, It can be seen that the PLQY of Example 1 in which the molar ratio of HBr and PbBr _{2 is 3:1 is 94%.}

Therefore, it can be confirmed that the PLQY value of the perovskite compound increases as the molar ratio of HBr, which is a halogen donor, increases, and it can be seen that the perovskite compound prepared using the halogen donor has excellent luminous efficiency.

3a and 3b are graphs showing PL (photoluminescence) spectra of the perovskite compounds of Comparative Examples 3 and 2, respectively, and FIGS. 3c and 3d are the perovskites of Comparative Examples 3 and 2, respectively. It is a graph showing the line width and PL spectral peak position of the compound.

First, referring to FIGS. 3A and 3B , it can be seen that in Comparative Example 3 prepared by the conventional hot injection method, halogen substitution reaction occurs non-uniformly and thus has a plurality of PL peaks.

On the other hand, in the case of Example 2 prepared by using a halogen donor, it can be confirmed that the halogen substitution reaction occurs uniformly and thus has a single PL peak.

Referring to FIGS. 3C and 3D , it can be seen that Example 2 manufactured using a halogen donor has a narrower line width than Comparative Example 3 manufactured by a conventional hot injection method.

Therefore, according to the present invention, the perovskite compound prepared using a halogen donor may have a uniform halogen anion composition, thereby narrowing the line width of a light emitting device including the same and increasing color purity.

4 is a graph showing luminance versus voltage of a perovskite photoelectric device according to an embodiment of the present invention.

Referring to FIG. 4 , in Example 3, it can be seen that the maximum luminance for R is 1317 cd/m ² , the maximum luminance for G is 3354 cd/m ² , and the maximum luminance for B is 612 cd/m ² . have.

5 is a graph showing the EL (electroluminescence) intensity of a perovskite photoelectric device according to an embodiment of the present invention.

Referring to FIG. 5 , it can be seen that Example 3 has a PL wavelength of about 42 8 nm for color B, about 523 nm for color G, and about 622 nm for color R.

6 is a graph illustrating external quantum efficiency of a perovskite photoelectric device according to an embodiment of the present invention.

Referring to FIG. 6, when a bias voltage of 5V is applied in Example 3, it can be seen that the EQE of R is 3.53%, the EQE of G is 10.01%, and the EQE of B is 2.67%.

7 is a graph showing color coordinates of a perovskite photoelectric device according to an embodiment of the present invention.

Referring to FIG. 7 , it can be seen that the CIE color coordinates of Example 3 are R(0.69,0.17), G(0.08,0.71), and B(0.167,0.00085).

Therefore, according to the present invention, a perovskite light emitting device having few impurities and high color purity can be manufactured through a perovskite compound prepared using a halogen donor.

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 are provided 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 (14)

preparing a metal halide-ligand solution comprising a divalent or trivalent metal cation and a monovalent anion;
Preparing a perovskite compound represented by the following formula by mixing the metal halide-ligand solution, a metal oleate solution containing a monovalent metal cation, and a halogen donor
includes,
The halogen donor is a method for producing a perovskite compound, characterized in that the solution containing the halogen anion.
[Formula]
A _a B _b X _c
(Where A is a monovalent metal cation, B is a divalent or trivalent metal cation, and X is a monovalent anion.)
a+2b=c (a,b,c are natural numbers) or a+3b=4c (a,b,c are natural numbers)
According to claim 1,
The method for producing a perovskite compound, characterized in that the halogen donor reacts with the metal oleate solution to form a metal halide.
According to claim 1,
The halogen donor is a method for producing a perovskite compound, characterized in that for generating a crystal nucleus of the perovskite compound.
4. The method of claim 3,
The perovskite compound is a perovskite, characterized in that at least one shape selected from the group consisting of nano-sized nanorods, nanoplates, nanocubes, and nanowire cubes. A method for preparing a skyte compound.
4. The method of claim 3,
The method for producing a perovskite compound, characterized in that the crystal size of the perovskite compound is 1 nm to 100 nm.
According to claim 1,
The method for producing a perovskite compound, characterized in that the halogen donor and the di- or trivalent metal cations contained in the metal halide-ligand solution are included in a molar ratio of 1:1 to 10:1.
According to claim 1,
Wherein X is a method for producing a perovskite compound, characterized in that it contains different halogen anions from each other by a halogen substitution reaction.
According to claim 1,
The perovskite compound is a method for producing a perovskite compound, characterized in that it is prepared at 20 ℃ to 150 ℃.
A perovskite photoelectric device comprising a perovskite compound prepared according to any one of claims 1 to 8.
10. The method of claim 9,
The perovskite compound includes different halogen anions from each other,
A perovskite photoelectric device, characterized in that the line width of the perovskite photoelectric device is controlled according to the exciton binding energy of the perovskite compound.
10. The method of claim 9,
PLQY (photoluminescence quantum yield) of the perovskite photoelectric device is a method for producing a perovskite compound, characterized in that 70% to 100%.
10. The method of claim 9,
A perovskite photoelectric device, characterized in that the PL (photoluminescence) line width of the perovskite photoelectric device is 10 nm to 30 nm.
10. The method of claim 9,
An electroluminescence (EL) line width of the perovskite photoelectric device is 15 nm to 40 nm.
10. The method of claim 9,
PL (photoluminescence) wavelength of the perovskite photoelectric device is a perovskite photoelectric device, characterized in that 350 nm to 1200 nm.

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