JP6786582B2 - Compounds and luminescent materials - Google Patents

Description

The present invention relates to compounds and luminescent materials.
This application claims priority based on Japanese Patent Application No. 2016-30201 filed in Japan on February 19, 2016 and Japanese Patent Application No. 2016-126043 filed in Japan on June 24, 2016. Is used here.

Conventionally, an organic-inorganic perovskite AMX ₃ compound composed of an organic cation (A), a halide ion (X), and a divalent metal ion (M) has been known. In recent years, there has been increasing interest in the conductivity and luminescence properties of compounds having a perovskite structure that have Group IV element (Ge, Sn, and Pb) ions at the metal ion position (M).

In particular, when the divalent metal ion is Pb (II), a strong luminescence phenomenon at room temperature has been observed in the range from the ultraviolet region to the red spectrum region (Non-Patent Document 1). It is also possible to adjust the emission wavelength depending on the type of halide ion (X) (Non-Patent Document 2).

M.Era, A.Shimizu and M.Nagano, Rep.Prog.Polym.Phys.Jpn., 42,473-474 (1999) L. Protesescu, S. Yakunin, M.I.Bodnarchuk, F. Krieg, R. Caputo, C.H. Hendon, R.X. Yang, A. Walsh, and M.V. Kovalenko, Nano Letter. 15, 3692-3696 (2015)

However, in order to industrially apply a compound having a perovskite structure as described in Non-Patent Documents 1 or 2 as a light emitting material, further improvement of the light emitting intensity of the compound is required.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a compound having a perovskite structure having a high emission intensity when used as a light emitting material, and a light emitting material containing the compound.

As a result of diligent studies by the present inventors in order to solve the above problems, the following inventions have been reached.

That is, the embodiment of the present invention includes the following inventions [1] to [6].
[1] A perovskite-type crystal having A, B, X, and M as components and having a molar ratio [M / (M + B)] obtained by dividing the amount of M by the total amount of M and B to be 0.7 or less. A compound having a structure.
(A is a monovalent cation located at each apex of the hexahedron centered on B in the perovskite type crystal structure.
B is a lead ion.
M is a divalent or trivalent metal ion and is a cation selected from metal ions having an ionic radius of 0.9 Å or more and 1.5 Å or less at the hexacoordinate, and at least a part of M is a cation. , A part of B is substituted in the perovskite type crystal structure.
X represents a component located at each apex of the octahedron centered on B in the perovskite type crystal structure, and is selected from the group consisting of chloride ion, bromide ion, fluoride ion, iodide ion and thiocyanate ion. It is one or more kinds of ions, and the X includes at least a chloride ion or a bromide ion. )
[2] The compound according to [1], which is represented by the following general formula (1).
AB _(1-a) M _a X _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0.7) ... (1)
(A, B, M, and X have the same meanings as described above.)
[3] The compound according to [1] or [2], wherein M is an ion of an alkaline earth metal.
[4] The compound according to [3], wherein the M is a calcium ion.
[5] The compound according to any one of [1] to [4], wherein A is an organic ammonium ion.
[6] A luminescent material containing the compound according to any one of [1] to [5].

According to the present invention, it is possible to provide a compound having a perovskite structure having high luminescence intensity and a luminescent material containing the compound.

Hereinafter, the present invention will be described in detail with reference to embodiments.
<Compound>
<< First Embodiment >>
In the first embodiment of the compound of the present embodiment, the value of the molar ratio [M / (M + B)] of A, B, X, and M as components and the amount of M divided by the total amount of M and B is 0. It is a compound having a perovskite type crystal structure of 0.7 or less.
In the present embodiment, A is a monovalent cation located at each apex of a hexahedron centered on B in the perovskite type crystal structure.
B is a Pb ion.
M is a divalent or trivalent metal ion and is a cation selected from metal ions having an ionic radius of 0.9 Å or more and 1.5 Å or less at the hexacoordinate, and at least a part of M is a cation. , A part of B is substituted in the perovskite type crystal structure.
X represents a component located at each apex of the octahedron centered on B in the perovskite type crystal structure, and is selected from the group consisting of chloride ion, bromide ion, fluoride ion, iodide ion and thiocyanate ion. It is one or more kinds of ions. However, X contains at least chloride ion or bromide ion. When 1 Å = 0.1 nm (the same applies hereinafter), the ionic radius of M at the 6-coordination is 0.09 nm or more and 0.15 or less.

Usually, the basic structure of a compound having a perovskite-type crystal structure is a three-dimensional structure or a two-dimensional structure.
Wherein when the basic structure is a three-dimensional structure, represented by A'B'X _'3. Here, A'represents an organic cation or an inorganic cation, B'represents a metal cation, and X'represents a halide ion or a thiocyanate ion.
The basic structure is the case of the two-dimensional structure, represented by A _'2 B'X' _4. Here, A', B'and X'represent the same meanings as described above.
If the basic structure of the three-dimensional structure or a two-dimensional structure, 'centered on the vertex X' B and has a three-dimensional network of corner-sharing octahedral represented by B'x _'6.
B'is a metal cation capable of taking the octahedral coordination of X'.
A'is located at each vertex of the hexahedron centered on B'.

In the present embodiment, the compound having a perovskite-type crystal structure containing A, B, X, and M as components is not particularly limited, and the basic structure is any of a three-dimensional structure, a two-dimensional structure, and a pseudo two-dimensional structure. It may be a compound having the structure of.
When the basic structure is a three-dimensional structure, the perovskite-type crystal structure is represented by AB _(1-a) M _a X _{(3 + δ)} .
When the basic structure is a two-dimensional structure, the perovskite-type crystal structure is represented by A ₂ B _(1-a) M _a X _{(4 + δ)} .
Here, the a represents the above-mentioned molar ratio [M / (M + B)].
The δ is a number that can be appropriately changed according to the charge balance of B and M, but is preferably 0 or more and 0.7 or less. For example, A is a monovalent cation, B is a divalent anion (Pb ion), M is a divalent or trivalent anion (metal ion), and X is a monovalent anion (chloride ion, In the case of one or more ions selected from the group consisting of bromide ion, fluoride ion, iodide ion and thiocyanate ion), δ can be selected so that the compound is neutral (charge is 0). it can.

In the present embodiment, in the compound having a perovskite type crystal structure, the metal cation of the B'component is a Pb ion (B component), and a part of a plurality of Pb ions (B component) is a M component, which is divalent or 3 The emission intensity of the compound can be improved by substituting with a cation selected from metal ions having a valence and an ionic radius of 0.9 Å or more and 1.5 Å or less at 6 coordinations. I found out what I could do.
At least a part of M in the compound having a perovskite type crystal structure according to the present embodiment means a component that replaces a part of the lead ion represented by B.
In the compound of the present embodiment, M may be present at a position where the B component (lead ion) is present, may be present at a position where the A component is present, or is basic in the above-mentioned basic structure. It may be present in the lattice gap of the skeleton constituting the structure.
The compound having a perovskite-type crystal structure containing A, B, X, and M as components in the present embodiment will be described later.

In the present embodiment, the perovskite type crystal structure means, for example, when a compound is measured by means of X-ray diffraction (XRD, Cu Kα ray, X'pert PRO MPD, manufactured by Spectris).
In the case of a perovskite compound having a three-dimensional structure: AB _(1-a) M _a X _{(3 + δ)} , the peak of (hkl) = (001) is usually at the position of 2θ = 12 to 18 °, or 2θ = 18 A compound having a peak derived from (hkl) = (100) at a position of ~ 25 °, preferably a peak of (hkl) = (001) at a position of 2θ = 13 to 16 °. It is a compound in which a peak derived from (hkl) = (100) exists at a position of 2θ = 20 to 23 °.
Two-dimensional structure perovskite compound: In the case of A ₂ B _(1-a) M _a X _{(4 + δ)} , a compound in which a peak derived from (hkl) = (002) usually exists at a position of 2θ = 1 to 10 °. This is preferably a compound in which a peak derived from (hkl) = (002) is present at a position of 2θ = 2 to 8 °.

<< Second Embodiment >>
In the compound of this embodiment, A is a monovalent cation, M is a divalent or trivalent metal ion, and the ion radius at the hexacoordination is 0.9 Å or more and 1.5 Å or less. It is a cation selected from ions, and X is one or more ions selected from the group consisting of chloride ion, bromide ion, fluoride ion, iodide ion and thiocyanate ion (however, X is at least one kind of ion). It contains chloride ions or bromide ions) and has a perovskite structure represented by the following general formula (1).
APb _(1-a) M _a X _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0.7) ... (1)
For example, A is a monovalent cation, B is a divalent anion (Pb ion), M is a divalent or trivalent anion (metal ion), and X is a monovalent anion (chloride ion, In the case of one or more ions selected from the group consisting of bromide ion, fluoride ion, iodide ion and thiocyanate ion), δ can be selected so that the compound is neutral (charge is 0). it can.

The basic structural form generally perovskite structure is A'B'X _'3 structure.
In the present embodiment, the basic structural form of perovskites, A'B'X 'is ₃ structure, corner-sharing B'x' having a three-dimensional network of ₆ octahedra. Component 'B ₃ structure'A'B'X is a metal cation that can adopt an octahedral coordination of X 'anion. The A'cation is located at each vertex of the hexahedron centered on the B'atom, and is an organic cation or an inorganic cation in this embodiment. Component 'X ₃ structure'A'B'X is in this embodiment is usually a halide ion.

As a result of diligent studies by the present inventors, in the basic structure of the compound having a perovskite structure, the metal cation of the B component is lead, and a part of a plurality of lead ions is replaced with another atom to obtain the compound. It has been found that the emission intensity can be improved.
In the present embodiment, the compound having a perovskite structure represented by the general formula (1) (hereinafter, may be referred to as “compound (1)”) is mainly A, Pb (lead), M and X. Use as an ingredient.
Here, M means an atom that replaces a part of Pb ion which is a metal cation. In addition, M may replace the position where the B component (lead ion) exists in the basic structure, may replace the position where the A component exists, and the lattice gap of the skeleton constituting the basic structure. May be present in.
Hereinafter, the compound having a perovskite-type crystal structure containing A, B, X, and M as components in the present embodiment will be described.

[A]
In the compounds of the first embodiment and the second embodiment, A is a monovalent cation. Among the compounds, A is preferably cesium ion or organic ammonium ion.

Specific examples of the organic ammonium ion of A include a cation represented by the following general formula (A1).

In the general formula (A1), R ^{1 to} R ⁴ are independently hydrogen atoms or alkyl groups, and one of the hydrogen atoms constituting each alkyl group may be substituted with an amino group.
As the alkyl group of R ^{1 to} R ^4, a linear or branched alkyl group is preferable, a linear or branched alkyl group having 1 to 4 carbon atoms is more preferable, and an alkyl group having 1 to 3 carbon atoms is more preferable. Linear or branched alkyl groups are more preferred. By reducing the number of alkyl groups and the number of carbon atoms of the alkyl groups, a three-dimensional perovskite structure having light emitting properties can be obtained. It ^is preferable that the total number of carbon atoms in the alkyl group of R 1 to R ⁴ is ^1-4, among the ^{R 1} ~R ^4, R 1 is an alkyl group having 1 to 3 carbon atoms, ^{R 2} It is particularly preferable that ~ R ⁴ is a hydrogen atom.

More specifically, A _is, CH ₃ ^NH _{3 +,} preferably _C 2 H 5 _NH ^{3 +} or _C ³ _H 7 _NH 3 is ^_+, CH ³ _NH 3 ⁺ or _C 2 _H 5 _NH ^{3 +} in more preferably _in, CH 3 and most preferably _NH ^{3 +} (ammonium ion).

[B]
In the compound having a perovskite structure of the present embodiment, the B component is a metal cation that is the center of the crystal structure. In this embodiment, the B component is Pb (lead). The Pb ion in this embodiment is a divalent Pb ion.
In the present embodiment, the emission intensity of the compound of the present embodiment can be improved by substituting a part of the B component (Pb ion) contained in the plurality of crystal structures constituting the compound with another atom.

[M]
In the compounds of the first embodiment and the second embodiment, at least a part of M replaces a part of Pb ion which is a metal cation.
More specifically, M is a divalent or trivalent metal ion and is a cation selected from metal ions having an ionic radius of 0.9 Å or more and 1.5 Å or less at the hexacoordinate.
The ionic radius of the metal ion represented by M is preferably 0.95 Å or more and 1.4 Å or less, and more preferably 0.95 Å or more and 1.3 Å or less.

From the viewpoint of maintaining the perovskite crystal structure of the compounds of the first embodiment and the second embodiment and obtaining sufficient emission intensity, M is, for example, barium ion (ionic radius at 6 coordination; 1.35 Å). ), Calcium ion (ionic radius at 6 coordination; 1.00 Å), cerium ion (ionic radius at 6 coordination; 1.01 Å), dysprosium ion (ionic radius at 6 coordination; 1.07 Å), Lantern ion (ionic radius at 6 coordination; 1.03 Å), samarium ion (ionic radius at 6 coordination; 1.19 Å), strontium ion (ionic radius at 6 coordination; 1.18 Å), or itterbium Examples include cations of elements such as ions (ionic radii at 6 coordinations; 1.02 Å). Among them, M is preferably an ion of an alkaline earth metal, and more preferably a calcium ion.

[A]
From the viewpoint of maintaining the crystal structure of the perovskite compound and obtaining sufficient emission intensity, the amount of substitution of M with respect to Pb is a when the molar ratio of a, M and Pb is expressed as a = M / (Pb + M). Is greater than 0 and less than or equal to 0.7. a is preferably 0.01 or more and 0.7 or less, and more preferably 0.02 or more and 0.6 or less.

In the present embodiment, the value of a is a value calculated from the value of the synthesized compound measured by ICP-MS described in the following {Method for calculating a].

{Measurement method of a}
In the compound according to the present embodiment, the value of a, that is, the molar ratio [M / (M + B)] can be measured using ICP-MS (ELAN DRCII, manufactured by PerkinElmer). The molar ratio is measured after dissolving a compound having a perovskite-type crystal structure with nitric acid or the like.
Specifically, the value of the molar ratio [M / (M + B)] is a value calculated according to the following formula (T). In the following formula (T), Mmol is the number of moles of M measured by ICP-MS, and Pbmol is the number of moles of Pb measured by ICP-MS.
[M / (M + B)] = (Mmol) / (Mmol + Pbmol)… (T)

In the present embodiment, from the viewpoint that the amount of substitution of M in the compound after synthesis with respect to Pb can be calculated more accurately, the value calculated by the above-mentioned {method for calculating a} is preferably set to "a".
In addition, simply, the value of a is the charging ratio adjusted so that a in the compounds of the first embodiment and the second embodiment becomes a desired value when synthesizing the compound of the present embodiment. It can also be calculated from the value.

[X]
X is one or more ions selected from the group consisting of chloride ion, bromide ion, fluoride ion, iodide ion and thiocyanate ion. However, X contains at least chloride ion or bromide ion.
The amount of chloride ion or bromide ion in X is preferably 10% or more, more preferably 30% or more, further preferably 70% or more, and particularly preferably 80% or more in terms of mol% in X. .. The upper limit value is not particularly limited, but can be arbitrarily selected as long as it is 100% or less.
Among them, X preferably contains bromide ions. When X is two or more kinds of anions, the anion content ratio can be appropriately selected depending on the emission wavelength.

When two or more kinds of ions are selected as X, a combination of a bromide ion and a chloride ion or a combination of a bromide ion and an iodide ion is preferable.

Specific examples of the compounds of the first embodiment and the second embodiment include CH ₃ NH ₃ Pb _(1-a) Ca _a Br _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0. 7), CH ₃ NH ₃ Pb _(1-a) Sr _a Br _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0.7), CH ₃ NH ₃ Pb _(1-a) La _a Br _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0.7), CH ₃ NH ₃ Pb _(1-a) Ba _a Br _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤) _{0.7), CH 3 NH 3 Pb} (1-a) Dy a Br (3 + δ) (0 <a ≦ 0.7,0 ≦ δ ≦ 0.7), CH 3 NH 3 Pb (1-a) Ca _a (Br ₂ Cl) _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0.7), or CH ₃ NH ₃ Pb _(1-a) Ca _a (Br ₂ I) _{(3 + δ)} (0 <A ≤ 0.7,0
≦ δ ≦ 0.7), etc. are mentioned as preferable ones.

The compound having the perovskite structure of the present embodiment can be synthesized by a self-assembling reaction using a solution.
For example, a solution in which a compound containing Pb and the above-mentioned X, a compound containing the above-mentioned M and the above-mentioned X, and the above-mentioned A and the above-mentioned compound containing X is dissolved in a solvent is applied to remove the solvent. Thereby, the compound having the perovskite structure of the present embodiment can be synthesized.
As another method, a coating film is formed by applying a solution in which a compound containing Pb and the above-mentioned X and the above-mentioned M and the above-mentioned compound containing X are dissolved in a solvent and removing the solvent. Then, the compound having the perovskite structure of the present embodiment can be synthesized by applying a solution in which the above-mentioned A and the above-mentioned compound containing X are dissolved in a solvent on the above-mentioned coating film and removing the solvent. ..
At the time of synthesis, the type and amount of the compound to be blended may be adjusted so that a and δ in the compounds of the first embodiment and the second embodiment have desired values.

≪Emission spectrum≫
The compound having a perovskite structure of the present embodiment is a luminescent material that fluoresces in the visible light wavelength region, and when X is a bromide ion, it usually has a wavelength range of 480 nm or more, preferably 500 nm or more, more preferably 520 nm or more. It emits fluorescence. Further, it usually emits fluorescence in a wavelength range of 700 nm or less, preferably 600 nm or less, and more preferably 580 nm or less.
The above upper limit value and lower limit value can be arbitrarily combined.

The maximum emission intensity of the compound having a perovskite structure of the present embodiment is determined from the maximum intensity in the visible light wavelength region measured using a fluorometer and the transmittance of excitation light measured using an ultraviolet visible absorptiometer. Can be done.
As the fluorometer, for example, a fluorometer (FT-6500) manufactured by JASCO Corporation can be used. As the ultraviolet-visible absorptiometer, for example, an ultraviolet-visible absorptiometer (trade name: V-670) manufactured by JASCO Corporation can be used.
In the present embodiment, the maximum emission intensity of the compound is a value corrected according to the following formula (S). In the following formula (S), Pmax is the maximum intensity in the visible light wavelength region, and Ep is the transmittance (%) of the excitation light.
Pmax / (100-Ep) x 100 ... (S)

<Luminescent material>
The present embodiment provides a luminescent material containing the compounds of the first embodiment and the second embodiment.
The luminescent material using the compounds of the first embodiment and the second embodiment may have components other than the compounds of the first embodiment and the second embodiment. For example, it may further contain some impurities or a compound having no perovskite structure and having a composition similar to or similar to that of the compounds of the first embodiment and the second embodiment described above.
The form of the luminescent material containing the compound having a perovskite structure is not particularly limited, and can be appropriately determined depending on the intended use. The compound of the first embodiment and the compound of the second embodiment may be a film formed into a film, or an adsorbent formed into a powder and adsorbed on a substrate.

The coating or adsorbent of the compound having the perovskite structure of the present embodiment is obtained by dissolving the compounds of the first embodiment and the second embodiment in an organic solvent, and then gravure coating method, bar coating method, printing method, and spraying method. , Spin coating method, dip method, die coating method and other coating methods.

The organic solvent is not particularly limited as long as it can dissolve the above-mentioned A, Pb, M, X, and other undissolved components to form ions. The organic solvent may have various organic compounds and a branched structure or a cyclic structure, and may have a plurality of functional groups such as -O-, -CO-, -COO-, or -OH. The hydrogen atom may be replaced with a halogen atom such as fluorine. Examples of the organic solvent include esters such as methyl formate, ethyl formate, propyl formate, pental formate, methyl acetate, ethyl acetate, and pentyl acetate; γ-butyrolactone, N-methyl-2-pyrrolidone, and acetone. , Dimethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, or methylcyclohexanone; diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane. , 4-Methyldioxolane, tetrahydrofuran, methyl tetrahydrofuran, anisol, or ethers such as phenetol; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2 -Alcohols such as methyl-2-butanol, methoxypropanol, diacetone alcohol, cyclohexanol, 2-fluoroethanol, 2,2,2-trifluoroethanol, or 2,2,3,3-tetrafluoro-1-propanol. Classes; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, or triethylene glycol dimethyl ether; N, N-dimethylformamide, acetamide, or N, N- Amid-based organic solvents such as dimethyl acetamide; nitrile-based organic solvents such as acetonitrile, isobutyronitrile, propionitrile, or methoxy acetonitrile; carboat-based organic solvents such as ethylene carbonate or propylene carbonate; methylene chloride, dichloromethane, or chloroform. Halogen-based organic solvents such as n-pentane, cyclohexane, n-hexane, benzene, toluene, or xylene, and the like; or dimethylsulfoxide and the like.

Further, after applying a solution in which the compounds of the first embodiment and the second embodiment are dissolved in the organic solvent, any one or more of depressurization, drying and blowing are performed as necessary to volatilize the organic solvent. Is preferable. Drying may be carried out at room temperature or may be carried out by heating. The temperature at the time of heating can be appropriately determined in consideration of the time required for drying and the heat resistance of the substrate, but is preferably 50 to 200 ° C, more preferably 50 to 100 ° C.

The technical scope of the present embodiment is not limited to the above-described embodiment, and various changes can be made without departing from the spirit of the present embodiment.

Hereinafter, embodiments of the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Synthesis of compounds having a perovskite structure)
[Example 1]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, calcium bromide (CaBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a calcium bromide solution having a concentration of 0.1 M. Then, methylammonium bromide (CH ₃ NH ₃ Br) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium bromide solution having a concentration of 0.1 M.
The above lead bromide solution and calcium bromide solution were mixed so that Ca / (Ca + Pb) was 0.03 in molar ratio to prepare a solution. The obtained mixed solution and the above-mentioned methyl ammonium bromide solution were further mixed so that the molar ratio of methyl ammonium bromide / (Ca + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.
The compound of the coating film was derived from (hkl) = (001) at a position of 2θ = 14 ° by measuring by means of X-ray diffraction (XRD, Cu Kα ray, X'pert PRO MPD, manufactured by Spectris). It was confirmed that it had a peak of 3D and had a three-dimensional perovskite structure.

[Example 2]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 1 above except that Ca / (Ca + Pb) was set to 0.05.

[Example 3]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 1 above except that Ca / (Ca + Pb) was set to 0.1.

[Example 4]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 1 above except that Ca / (Ca + Pb) was set to 0.2.

[Comparative Example 1]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Methylammonium bromide (CH ₃ NH ₃ Br) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium bromide solution having a concentration of 0.1 M. Then, the solutions were mixed so that the molar ratio was methylammonium bromide / Pb = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Comparative Example 2]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead iodide (PbI ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a lead iodide solution having a concentration of 0.1 M. Methylammonium iodide (CH ₃ NH ₃ I) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium iodide solution having a concentration of 0.1 M. Then, the solutions were mixed so that the molar ratio was methylammonium iodide / Pb = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Comparative Example 3]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead iodide (PbI ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a lead iodide solution having a concentration of 0.1 M. Similarly, calcium iodide (CaI ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a calcium iodide solution having a concentration of 0.1 M.
The above lead iodide solution and calcium iodide solution were mixed so that Ca / (Ca + Pb) was 0.05 in molar ratio to prepare a solution. The obtained mixed solution and the methylammonium bromide solution described in [Example 1] were further mixed so that the molar ratio of methylammonium bromide / (Ca + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

(Measurement of emission spectrum)
The emission spectrum of the coating film of the compound having a perovskite structure obtained in Examples 1 to 4 and Comparative Example 1 was measured by a fluorometer (manufactured by Nippon Spectrometer, trade name FT-6500, 430 nm or less wavelength cut filter, excitation light 430 nm, Sensitivity high) was used for measurement. In addition, the transmittance (%) was measured using an ultraviolet-visible absorptiometer of the coating film. As the ultraviolet-visible absorptiometer, JASCO Corporation's trade name V-670 was used (the same equipment was also used below).
The comparison of the emission intensities between the coating films was performed by correcting the maximum emission intensity near the wavelength of 530 nm by the following formula (S) -1.
[Maximum emission intensity near wavelength 530 nm / (transmittance at 100-wavelength 430 nm)] × 100… (S) -1

(Measurement of emission spectrum)
The emission spectrum of the coating film of the compound having a perovskite structure obtained in Comparative Examples 2 and 3 was measured by a fluorometer (manufactured by Nippon Spectrometer, trade name FT-6500, wavelength cut filter of 600 nm or less, excitation light 550 nm, sensitivity high). Was measured using. In addition, the transmittance was measured using an ultraviolet-visible absorptiometer of the coating film.
The comparison of the emission intensities between the coating films was performed by correcting the maximum emission intensity near the wavelength of 750 nm by the following formula (S) -2.
[Maximum emission intensity near wavelength 750 nm / (transmittance at 100-wavelength 550 nm)] × 100… (S) -2

Table 1 below describes the composition of the compounds having the perovskite structure of Examples 1 to 4 and Comparative Examples 1 to 3 in the preparation of the solution, and the maximum emission intensity. In Table 1, "M / (M + Pb)" is a value in the charging ratio of "a" in the above general formula (1).

From the above results, the light emitting materials of Examples 1 to 4 containing the compound having a perovskite structure according to the present embodiment have excellent light emitting intensity as compared with the compounds having a perovskite structure of Comparative Examples 1 to 3. I was able to confirm that.

(Synthesis of compounds having a perovskite structure)
[Example 5]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, strontium bromide (SrBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a strontium bromide solution having a concentration of 0.1 M. Then, methylammonium bromide (CH ₃ NH ₃ Br) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium bromide solution having a concentration of 0.1 M.
The above lead bromide solution and strontium bromide solution were mixed so that Sr / (Sr + Pb) was 0.1 in terms of molar ratio to prepare a solution. The obtained mixed solution and the above-mentioned methyl ammonium bromide solution were further mixed so that the molar ratio was methyl ammonium bromide / (Sr + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Example 6]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 5 above except that Sr / (Sr + Pb) was set to 0.2.

[Example 7]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 5 above except that Sr / (Sr + Pb) was set to 0.3.

[Example 8]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 5 above except that Sr / (Sr + Pb) was set to 0.5.

[Example 9]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, lanthanum bromide (LaBr ₃ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a lanthanum bromide solution having a concentration of 0.1 M. Then, methylammonium bromide (CH ₃ NH ₃ Br) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium bromide solution having a concentration of 0.1 M.
The above lead bromide solution and strontium bromide solution were mixed so that the molar ratio of La / (La + Pb) was 0.05 to prepare a solution. The obtained mixed solution and the above-mentioned methyl ammonium bromide solution were further mixed so that the molar ratio of methyl ammonium bromide / (La + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Example 10]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 9 except that La / (La + Pb) was set to 0.1.

(Measurement of emission spectrum)
The method for comparing the luminescence intensity was the same as in Examples 1 to 4 and Comparative Example 1 described above.

Table 2 below describes the composition of the compounds having the perovskite structure of Examples 5 to 10 and Comparative Example 1 in the preparation of the solution, and the maximum emission intensity. In Table 2, "M / (M + Pb)" is a value in the charging ratio of "a" in the above general formula (1).

From the above results, the luminescent materials of Examples 5 to 10 containing the compound having a perovskite structure according to the present embodiment have excellent luminescence intensity as compared with the compound having a perovskite structure of Comparative Example 1. I was able to confirm that.

≪Measurement by ICP-MS≫
1 mL of nitric acid was added to the compound having a perovskite crystal structure on the glass substrate obtained in Examples 5 to 8 to dissolve the compound having a perovskite crystal structure. The solution after dissolution was made up to a total of 10 ml with ion-exchanged water, and the amounts of Pb and M were measured by ICP-MS (ELAN DRCII, manufactured by PerkinElmer), and the amount of M contained in the compound having a perovskite type crystal structure was (). The evaluation was made by applying the formula of M) / (M + Pb).
As a result of measurement by ICP-MS, the value of [M / (M + Pb)] in Example 5 was 0.10.
As a result of measurement by ICP-MS, the value of [M / (M + Pb)] in Example 6 was 0.20.
As a result of measurement by ICP-MS, the value of [M / (M + Pb)] in Example 7 was 0.29.
As a result of measurement by ICP-MS, the value of [M / (M + Pb)] in Example 8 was 0.51.

[Example 11]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, barium bromide (BaBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a barium bromide solution having a concentration of 0.1 M. Then, methylammonium bromide (CH ₃ NH ₃ Br) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium bromide solution having a concentration of 0.1 M.
The above lead bromide solution and barium bromide solution were mixed so that the molar ratio of Ba / (Ba + Pb) was 0.03 to prepare a solution. The obtained mixed solution and the above-mentioned methyl ammonium bromide solution were further mixed so that the molar ratio of methyl ammonium bromide / (Ba + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Example 12]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 11 above except that Ba / (Ba + Pb) was set to 0.05.

[Example 13]
A coating film of a compound having a perovskite structure was obtained in the same manner as in Example 11 above except that Ba / (Ba + Pb) was set to 0.1.

[Example 14]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, dysprosium bromide (DyBr ₃ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a dysprosium bromide solution having a concentration of 0.1 M. Then, methylammonium bromide (CH ₃ NH ₃ Br) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium bromide solution having a concentration of 0.1 M.
The above lead bromide solution and dysprosium bromide solution were mixed so that the molar ratio of Dy / (Dy + Pb) was 0.1 to prepare a solution. The obtained mixed solution and the above-mentioned methyl ammonium bromide solution were further mixed so that the molar ratio of methyl ammonium bromide / (Dy + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Example 15]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, calcium bromide (CaBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a calcium bromide solution having a concentration of 0.1 M. Then, methylammonium chloride (CH ₃ NH ₃ Cl) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium chloride solution having a concentration of 0.1 M.
The above lead bromide solution and calcium bromide solution were mixed so that Ca / (Ca + Pb) was 0.1 in molar ratio to prepare a solution. The obtained mixed solution and the above-mentioned methylammonium chloride solution were further mixed so that the molar ratio was methylammonium chloride / (Ca + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Example 16]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Similarly, calcium bromide (CaBr ₂ ) was dissolved in a solvent of DMF at 70 ° C. to prepare a calcium bromide solution having a concentration of 0.1 M. Then, methylammonium iodide (CH ₃ NH ₃ I) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium iodide solution having a concentration of 0.1 M.
The above lead bromide solution and calcium bromide solution were mixed so that Ca / (Ca + Pb) was 0.1 in molar ratio to prepare a solution. The obtained mixed solution and the above-mentioned methyl ammonium iodide solution were further mixed so that the molar ratio of methyl ammonium iodide / (Ca + Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Comparative Example 4]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Then, methylammonium chloride (CH ₃ NH ₃ Cl) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium chloride solution having a concentration of 0.1 M. Then, the solution was further mixed so that the molar ratio was methylammonium chloride / (Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

[Comparative Example 5]
A glass substrate having a size of 2.5 cm × 2.5 cm was prepared. This glass substrate was treated with ozone UV.
Lead bromide (PbBr ₂ ) was dissolved in a solvent of N, N-dimethylformamide (hereinafter referred to as "DMF") at 70 ° C. to prepare a lead bromide solution having a concentration of 0.1 M. Then, methylammonium iodide (CH ₃ NH ₃ I) was dissolved in a solvent of DMF at 70 ° C. to prepare a methylammonium iodide solution having a concentration of 0.1 M. Then, the solution was further mixed so that the molar ratio was methylammonium iodide / (Pb) = 1.
The solution was applied to the above glass substrate by spin coating at a rotation speed of 1000 rpm and dried in the air at 100 ° C. for 10 minutes to obtain a coating film of a compound having a perovskite structure.

(Measurement of emission spectrum)
The emission spectrum of the coating film of the compound having a perovskite structure obtained in Examples 11 to 14 was measured using a fluorometer (manufactured by JASCO Corporation, trade name FT-6500, excitation light 430 nm, sensitivity High). In addition, the transmittance (%) was measured using an ultraviolet-visible absorptiometer of the coating film.
The comparison of the emission intensities between the coating films was performed by correcting the maximum emission intensity near the wavelength of 530 nm by the following formula (S) -3.
[Maximum emission intensity near wavelength 530 nm / (transmittance at 100-wavelength 430 nm)] × 100… (S) -3

(Measurement of emission spectrum)
The emission spectrum of the coating film of the compound having a perovskite structure obtained in Example 15 and Comparative Example 4 was measured using a fluorometer (manufactured by JASCO Corporation, trade name FT-6500, excitation light 430 nm, sensitivity High). .. In addition, the transmittance (%) was measured using an ultraviolet-visible absorptiometer of the coating film.
The comparison of the emission intensities between the coating films was performed by correcting the maximum emission intensity near a wavelength of 500 nm by the following formula (S) -4.
[Maximum emission intensity near wavelength 500 nm / (transmittance at 100-wavelength 430 nm)] × 100… (S) -4

(Measurement of emission spectrum)
The emission spectrum of the coating film of the compound having a perovskite structure obtained in Example 16 and Comparative Example 5 was measured using a fluorometer (manufactured by JASCO Corporation, trade name FT-6500, excitation light 430 nm, sensitivity High). .. In addition, the transmittance (%) was measured using an ultraviolet-visible absorptiometer of the coating film.
The comparison of the emission intensities between the coating films was performed by correcting the maximum emission intensity near the wavelength of 540 nm by the following formula (S) -5.
[Maximum emission intensity near wavelength 540 nm / (transmittance at 100-wavelength 430 nm)] × 100… (S) -5

Tables 3 and 4 below describe the composition of the compounds having the perovskite structure of Examples 11 to 14 and Comparative Examples 4 to 5 in the preparation of the solution, and the maximum emission intensity. In Tables 3 and 4, "M / (M + Pb)" is a value in the charging ratio of "a" in the general formula (1).

As shown in the above results, Examples 11 to 13 in which barium ions are used as divalent or trivalent metal ions and Example 14 in which dysprosium ions are applied to which this embodiment is applied apply this embodiment. The maximum emission intensity was higher than that of Comparative Example 1.
Further, Example 15 in which two kinds of halide ions (Br and Cl) were used as X and the present embodiment was applied had a higher maximum emission intensity than Comparative Example 4 in which the present embodiment was not applied.
Similarly, Example 16 in which two types of halide ions (Br and I) were used as X and the present embodiment was applied had a higher maximum emission intensity than Comparative Example 5 in which the present embodiment was not applied.

According to this embodiment, it is possible to provide a compound having a perovskite structure having high luminescence intensity and a luminescent material containing the compound.
Therefore, the compound having the perovskite structure of the present embodiment and the light emitting material using the compound can be suitably used in the field of light emitting related materials.

Claims (5)

A, B, X, and M is a component, Ri 0.7 der less larger than the value 0 mole ratio obtained by dividing a total amount of the amount of M M and B [M / (M + B )], wherein A Is an organic ammonium ion, a compound having a perovskite-type crystal structure.
(A is a monovalent cation located at each apex of the hexahedron centered on B in the perovskite type crystal structure.
B is a Pb ion.
M is a divalent or trivalent metal ion and is a cation selected from metal ions having an ionic radius of 0.9 Å or more and 1.5 Å or less at the hexacoordinate, and at least a part of M is a cation. , A part of B is substituted in the perovskite type crystal structure.
X represents a component located at each apex of the octahedron centered on B in the perovskite type crystal structure, and is selected from the group consisting of chloride ion, bromide ion, fluoride ion, iodide ion and thiocyanate ion. It is one or more kinds of ions, and the X includes at least a chloride ion or a bromide ion. ) The compound according to claim 1, which is represented by the following general formula (1).
AB _(1-a) M _a X _{(3 + δ)} (0 <a ≤ 0.7, 0 ≤ δ ≤ 0.7) ... (1)
(A, B, M, and X have the same meanings as described above.) The compound according to claim 1 or 2, wherein M is an ion of an alkaline earth metal. The compound according to claim 3, wherein M is a calcium ion. A luminescent material containing the compound according to any one of claims 1 to 4 .