KR20170114620A - Compound having Double Perovskite Structure and Solar Cell using Thereof - Google Patents

Abstract

The present invention relates to a lead-free perovskite compound which does not contain lead, and the perovskite compound according to the present invention has a direct band gap and satisfies the formula (1).
(Formula 1)
A ₂ (M ^I M ^III ) X ₆
Wherein A is a monovalent cation, A is at least one selected from an alkali ion, an organic ammonium ion and an amidinium group ion, M ¹ is a monovalent metal ion, M ^III is a trivalent metal Ion, and X is a halogen ion.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a perovskite compound and a solar cell containing the perovskite compound.

The present invention relates to a compound having a perovskite structure and a solar cell containing the same, and more particularly, to a lead-free double perovskite compound capable of effectively replacing a conventional lead-based organic-inorganic perovskite compound .

An organic / organic hybrid perovskite compound, also referred to as an organometallic halide perovskite compound, is composed of an organic cation (A), a metal cation (M) and a halogen anion (X) It is a material with a robust structure. These organic / organic hybrid perovskite compounds have very low material cost, are capable of low-temperature process and low-cost solution process, are excellent in commerciality, and have been actively studied in various fields such as light emitting devices, memory devices, sensors and photovoltaic devices .

As described above, the organic / organic hybrid perovskite compound is self-assembled and crystallized. However, since it is difficult to control the crystallization and self-assembly characteristics at a low temperature, It is difficult to produce a thin film having a dense and flat surface.

The present applicant has proposed a novel solar cell having a remarkably high power generation efficiency through Korean Patent Laid-Open Publication No. 2014-0035284. The present applicant has proposed a novel solar cell using a solution coating method using an organic / organic hybrid perovskite A method for producing a compound film has also been proposed.

However, the organic / organic hybrid perovskite compounds exhibiting the maximum efficiency to date have a limit of Pb-based heavy metal. Pb has adverse effects on human hematopoiesis and the nervous system, especially kidneys and other organs in infants. It is also known as the National Sanitation Foundation (NSF) and the Restriction of Hazardous Substances Directive (RoHS) , Attention is paid to pollution and damage caused by Pb, and there is a limitation on the use of Pb. Therefore, in order to commercialize a perovskite compound-based device, it is a reality that a lead-free perovskite compound having excellent photoelectric efficiency must be developed.

Korean Patent Publication No. 2014-0035284

It is an object of the present invention to provide a lead-free perovskite-based compound which does not contain lead. Another object of the present invention is to provide a lead-free perovskite compound which absorbs sunlight efficiently without containing lead and has excellent photoelectric properties.

The perovskite compound according to the present invention has a direct band gap, satisfies the formula (1), and is free from lead.

(Formula 1)

A ₂ (M ^I M ^III ) X ₆

Wherein A is a monovalent cation, A is at least one selected from an alkali ion, an organic ammonium ion and an amidinium group ion, M ¹ is a monovalent metal ion, M ^III is a trivalent metal Ion, and X is a halogen ion.

The perovskite compound according to an embodiment of the present invention is characterized by having a double perovskite structure.

In the perovskite compound according to an embodiment of the present invention, M ^I may be In ⁺ or M ^III may be In ³⁺ or Ga ³⁺ .

In a perovskite based compound according to one embodiment of the present invention, the M ^I -M ^III pair may be selected from i) to v) below.

i) In ¹⁺ -Sb ³⁺

ii) In ¹⁺ -Bi ³⁺

iii) Cu ¹⁺ -In ³⁺

iv) Ag ¹⁺ -In ³⁺

v) Ag ¹⁺ -Ga ³⁺

The perovskite compound according to an embodiment of the present invention may have a band gap energy of 1 to 2.5 eV.

In the perovskite compound according to an embodiment of the present invention, X may be selected from one or more of I ^- , Br ^- and Cl ^- .

The present invention includes a solar cell containing the above-mentioned perovskite compound as a light absorber.

Since the perovskite compound according to the present invention is a lead-free perovskite compound that does not contain lead, it has an advantage of being harmless to the human body and the environment. Furthermore, the perovskite-based compound according to the present invention has a direct transition band gap, has a band gap suitable for solar absorption, has an electron effective mass and a hole effective mass remarkably low, And can have substantially the same photoelectric characteristics as those of the conventional lead-based perovskite compound and can substantially replace the conventional lead-based perovskite compound.

1 is an energy band structure of a perovskite compound according to an embodiment of the present invention,
2 is an energy band structure of a perovskite compound according to another embodiment of the present invention,
3 is an energy band structure of a perovskite compound according to another embodiment of the present invention,
4 is an energy band structure of a perovskite compound according to another embodiment of the present invention,
5 is an energy band structure of a perovskite compound according to another embodiment of the present invention.

Hereinafter, the perovskite compound of the present invention will be described in detail with reference to the accompanying drawings. The following drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

The direct band gap means that the semiconductor material has a direct transition energy band structure. Specifically, when an electron transitions from a valence band to a conduction band, it is classified as a direct transition and an indirect transition according to the change in the momentum. In the case of a direct transition, the electron transition efficiency is greater than that of the indirect transition because there is no need to change the electron momentum. As a result, semiconductors with a direct transition bandgap can more effectively absorb and emit light. As a practical example, a perovskite compound CH ₃ NH ₃ PbX ₃ (X is a halogen ion) exhibiting maximum efficiency up to now is also a material having a direct transition band gap.

The excellent photoelectric characteristics of the lead-based perovskite compound typified by APbX ₃ (organic cation having A = 1 valence and X = halogen ion) are excellent because of the band gap energy (Eg, eV) suitable for solar absorption and the direct transition band gap Structure.

Therefore, in order to substantially replace the lead-based perovskite compound, the lead-free perovskite compound should have an energy bandgap suitable for solar absorption and a structure of a direct transition bandgap.

The Applicant has conducted long and in-depth studies on lead-free perovskite compounds which can substantially and immediately replace the lead-based perovskite compounds, and as a result, found that when divalent metal ions are replaced by monovalent metal ions and trivalent metal ions , And found that a lead-free compound that does not contain Pb can have a direct transition band gap when a specific composition is satisfied.

The perovskite-based compound according to the present invention based on the above-described findings has a direct band gap, satisfies the following formula (1), and is free from lead.

(Formula 1)

A ₂ (M ^I M ^III ) X ₆

Wherein A is a monovalent cation, A is at least one selected from an alkali ion, an organic ammonium ion and an amidinium group ion, M ¹ is a monovalent metal ion, M ^III is a trivalent metal Ion, and X is a halogen ion. At this time, the alkali ion may include Cs < ⁺ >.

More specifically, the perovskite-based compound according to the present invention satisfies the formula (1) and has a double perovskite structure. Such a double perovskite structure is known from metal oxide based perovskite materials and is also referred to as a superlattice structure.

In detail, the perovskite compound according to the present invention is a double perovskite compound having a double perovskite structure, which has a direct band gap and satisfies the formula (1) It does not contain any special features.

A lead-based perovskite compound typified by APbX ₃ (A = 1 organic cation, X = halogen ion) has a simple perovskite structure. The single perovskite structure is an organic cation in the middle of a three-dimensional network of PbX ₃ (or divalent metal MX ₃ ) octahedron corners-sheared. In a single perovskite structure, a bivalent metal ion (M) such as Pb is located at the center of a unit cell, and a halogen ion (X) is located at the center of each surface of the unit cell And the monovalent organic cation (A) may be located at each corner of the unit cell.

공간군(space group)에 속할 수 있다.On the other hand, the perovskite compound according to the present invention has a double perovskite structure, and the double perovskite structure has a monovalent metal ion (M ^I ) at the M-site of a single perovskite structure, And a trivalent metal ion (M ^III ) are regularly arranged, and may have a chemical formula of A ₂ M ^I M ^III X ₆ . Specifically, the double perovskite structure is a three-dimensional network in which the M ^I X ₃ octahedron and the M ^III X ₃ octahedron are alternately and periodically arranged in a corner-shearing three-dimensional network with organic cations in the middle . Such a dual perovskite structure may be a cubic crystal system

It can belong to a space group.

Specifically, the perovskite compound according to an embodiment of the present invention is a compound having a double band perovskite structure having a direct band gap and satisfying the following formula (2) Perovskite compound.

(2)

A ₂ (M ^I M ^III ) X ₆

In formula (2), A is a monovalent cation, at least one selected from Cs ⁺ , an organic ammonium ion and an amidinium group, M ^I is a monovalent metal ion, M ^III is a trivalent metal ion , X is a halogen ion, M ^I is In ^+, or M ^III is In ³⁺ or Ga ³⁺ .

That is, the perovskite compound according to one embodiment of the present invention contains In as a monovalent metal ion or trivalent metal ion, or Ga as a trivalent metal ion. In the case where In is contained as a monovalent metal ion or a trivalent metal ion, or Ga is contained as a trivalent metal ion, it may have a double perovskite structure more stably.

More specifically, the perovskite-based compound according to one embodiment of the present invention may contain In ⁺ as a monovalent metal ion, or may contain In ³⁺ as a trivalent metal ion. Specifically, it is preferable to use a compound containing In ⁺ as a monovalent metal ion and Sb ³⁺ or Bi ³⁺ as a trivalent metal ion, or containing In ³⁺ as a trivalent metal and Cu ⁺ or Ag ⁺ as a monovalent metal ion ≪ / RTI >

When the perovskite-based compound contains In ⁺ as a monovalent metal ion, it can have a remarkably small effective hole mass, and can exhibit high hole mobility. In addition, when In 3 ⁺ is contained as a trivalent metal ion, it can have a very small electron effective mass, and can exhibit high electron mobility. Further, when containing In ³⁺ free of In ^+, or trivalent metal ion to a monovalent metal ion, a trivalent metal ion or a monovalent metal ion and / or a halogen ion that is paired with the In ions, such as By tuning, it is possible to have a band gap in a range very suitable for solar absorption.

Specifically, in the perovskite-based compound according to one embodiment of the present invention, the M ¹ -M ^III pair of formula (1) may be selected from the following i) to v).

i) In ¹⁺ -Sb ³⁺

ii) In ¹⁺ -Bi ³⁺

iii) Cu ¹⁺ -In ³⁺

iv) Ag ¹⁺ -In ³⁺

v) Ag ¹⁺ -Ga ³⁺

The metal cation pairs of i) to v) are metal ion pairs having a direct transition bandgap, having a bandgap capable of absorbing solar light, and having a double perovskite structure stably formed.

More specifically, in the perovskite-based compound according to one embodiment of the present invention, the M ¹ -M ^III pair of formula (1) may be In ¹⁺ -Sb ³⁺ or In ¹⁺ -Bi ³⁺ .

That is, the perovskite compound according to an embodiment of the present invention may satisfy the following formula (3).

(Formula 3)

A ₂ (In ^I Sb ^III ) X ₆

In formula (3), A is a monovalent cation, Cs ^+, or an organic ammonium ion or an amidinium group ion. In ^I is a monovalent In ion and Sb ^III is a trivalent Sb ion And X is a halogen ion.

(Formula 4)

A ₂ (In ^I Bi ^III ) X ₆

In the formula (4), A is a monovalent cation, Cs ⁺ or an organic ammonium ion and an amidinium group ion, wherein In ¹ is a monovalent In ion and Bi ^III is a trivalent Bi ion And X is a halogen ion.

The monovalent metal ions are In, 3-valent metal ion is Sb or the case of Bi, 10 ^-2 and at the same time having a very small effective mass of a hole of the order (order), 10 ^-2 extremely small electron effective mass of the order (order) Lt; / RTI > Further, when the monovalent metal ion is In and the trivalent metal ion is Sb, as shown in Formula 3, a wide band gap capable of absorbing the sunlight in a wide wavelength range similar to Pb is provided, and represented by APbX ₃ Based perovskite compound which is equivalent to or better than the Pb-based perovskite compound.

In the perovskite compound according to one embodiment of the present invention, the organic ammonium ion of the monovalent cation (A) in the general formulas (1) to (4) may satisfy the following general formulas (5) to (6).

(Formula 5)

R ₁ -NH ₃ ⁺

In formula (5), R ₁ is C1-C24 alkyl, C3-C20 cycloalkyl or C6-C20 aryl.

(Formula 6)

R ₂ -C ₃ H ₃ N ₂ ⁺ -R ₃

R 6 in formula ₂ is an aryl-cycloalkyl or C6-C20 alkyl, C3-C20 of C1-C24, R ₃ is hydrogen or alkyl of C1-C24.

In the general formulas (1) to (4), the amidinium ion may satisfy the following general formula (7).

(Formula 7)

In formula (7), R ₄ to R ₈ are, independently of each other, hydrogen, C 1 -C ₂₄ alkyl, C 3 -C 20 cycloalkyl or C 6 -C 20 aryl.

In the general formulas (1) to (4), A represents an alkali ion including Cs ⁺ , an organic ammonium ion represented by the general formulas (5) to (6), an amidinium group or an organic ammonium ion represented by the general formula . When both the organic ammonium ion and the amidinium ion are contained, the charge mobility of the perovskite compound can be remarkably improved.

When A contains both an organic ammonium ion and an amidinium ion, it may contain an amidinium ion of 0.7 to 0.95 and an organic ammonium ion of 0.3 to 0.05, with the total number of moles of monovalent organic cations being 1 have. That is, in the general formulas (1) to (4), A may be A ^a _(1-x) A ^b _{x wherein} A ^a is an amidinium ion, A ^b is an organic ammonium ion, It can be a mistake of. The molar ratio between the amidinium ions and the organic ammonium ions, that is, the molar ratio of the amidinium ions in the range of 0.7 to 0.95 mol: 0.3 to 0.05 mol of the organic ammonium ions, can absorb light in a very wide wavelength band, exciton movement and separation, and faster photoelectrons and optical hole movement can be achieved.

R ₁ in the formula (5), R ₂ to R _{3 in the} formula (6) and / or R ₄ to R ₈ in the formula (7) can be appropriately selected depending on the use of the perovskite compound.

In detail, the size of the unit cell of the perovskite compound affects the band gap of the perovskite compound. Accordingly, in consideration of the use of a perovskite compound film such as a light emitting layer, a semiconductor layer, a light absorbing layer, and a charge storage layer, R ₁ to R 5 in Chemical Formula 5, R ₂ to R ₃ and / or R ₄ to R _{8 in the general} formula (7) can be suitably controlled, which is well known to those skilled in the art of semiconductor devices and optical devices.

As a specific example, when considering the band gap energy suitable for use as a solar cell, in Formula 5, R ₁ may be C1-C24 alkyl, specifically C1-C7 alkyl, more specifically methyl. In formula (6), R ₂ may be C1-C24 alkyl and R ₃ may be hydrogen or C1-C24 alkyl. Specifically, R ₂ may be C ₁ -C 7 alkyl and R ₃ may be hydrogen or C 1 -C 7 Alkyl, more particularly R < ₂ > may be methyl and R < ₃ > may be hydrogen. In the formula (7), R ₄ to R ₈ independently of each other may be hydrogen, amino or C 1 -C ₂₄ alkyl, specifically hydrogen, amino or C 1 -C 7 alkyl, more particularly hydrogen, amino or methyl, more particularly R ₄ is hydrogen, amino or methyl may be R ₅ to R ₈ are hydrogen. Specific and non-limiting one example, an amidinyl you umgye ions formamidinium nium _{(formamidinium, NH 2 CH = NH} 2 +) ions, acetic amidinyl nium _{(acetamidinium, NH 2 C (CH} 3) = NH 2 +) Or guanidinium (NH ₂ C (NH ₂ ) = NH ₂ ⁺ ), and the like.

As described above, specific examples of the organic cation (A) are an example in which the use of the perovskite compound film, that is, the use of sunlight as a light absorbing layer is taken into consideration. The design of the wavelength band of the light to be absorbed, R ₁ in Chemical Formula 5, R ₂ to R _{3 in} Chemical Formula 6, and / or R _{2 in} Formula ( ₁ ) are selected in consideration of the design of the light emitting wavelength band when used as a light emitting layer and the energy band gap and threshold voltage when used as a semiconductor device of a transistor. R ₄ to R _{8 in} formula (7) may be appropriately selected.

In the general formulas (1) to (4), X of X ₆ is a halogen anion. The halogen anion may be selected from one or more of I ^- , Br ^- , F ^- and Cl ^- . Specifically, the halogen anion may include one or two or more selected ions from iodine ion (I ^- ), chlorine ion (Cl ^- ) and bromine ion (Br ^- ). More specifically, the halogen anion may be an iodine ion (I ^- ), a chlorine ion (Cl ^- ), a bromine ion (Br ^- ), or an iodine ion and a bromine ion. Specific examples, in formula 1, Formula 2, Formula 3 or Formula 4, X is X ^a _(1-y) may be a X ^b _y, X ^a and X ^b are different from each other halogen ions (iodide ion (I ^-), chlorine ion (Cl ^-) and bromide (Br ^-) and are different from each other a halogen ion selected from), y can be a real number 0 <y <1.

In view of the wide band gap favorable for solar absorption, it is preferable that the halogen anion of the formulas (1) to (4) is iodine ion, chlorine ion or bromine ion, and in particular, the halogen anion of formulas (3) good. Further, from the viewpoint of improving the crystallinity and moisture resistance of the perovskite compound, the halogen anion may contain both iodine ion and bromine ion.

More specifically, X may be X ^a _(1-y) X ^b _y , X ^a iodine ion, X ^b is bromine ion, y is 0.05 Y &lt; / = 0.5, specifically 0.1? Y? 0.4. In other words, when the halogen anion contains both iodine ion and bromine ion in order to have a wide band gap favorable for absorption of sunlight, to prevent deterioration due to moisture, and to have excellent crystallinity even at a low temperature process of 100 ° C or lower, May contain 0.5 to 0.95 iodine ions and 0.5 to 0.05 bromine ions, preferably 0.6 to 0.9 iodine ions and 0.4 to 0.1 bromine ions, assuming that the total molar amount of the iodine ions is 1.

On the basis of the above description, one specific example of the specific non-limiting perovskite compound in which the monovalent metal ion is In ¹⁺ and the trivalent metal ion is Sb ³⁺ is, for example, a perovskite- _{3 NH 3) 2 InSb (I} x Cl y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( CH 3 NH 3) 2 InSb (I x Br y ) ₆ (0≤x≤1 mistake, 0≤y≤1 of the real and x + y = 1), ( CH 3 NH 3) 2 InSb (Cl x Br y) 6 (0≤x≤1 real number, 0≤y≤1 the real and x + y = 1), ( CH 3 NH 3) 2 InSb (I x F y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y _{= 1), (NH 2 CH} = NH 2) 2 InSb (I x Cl y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 CH = _{NH 2) 2 InSb (I x} Br y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 CH = NH 2) 2 InSb (I x Br _{y) 6} (0.5≤x≤0.95 mistake, 0.05≤y≤0.5 the real and x + y = 1), ( NH 2 CH = NH 2) 2 InSb (Cl x Br y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 CH = NH 2) 2 InSb (I x F y) 6 (0≤x≤1 Real number, the real number 0≤y≤1 and x + y = 1), ( NH 2 CH = NH 2 (1-x) CH 3 NH 3x) 2 InSb (I (1-y) Br y) 6 (x is and the 0 <x <1 real number, y is 0 <y <1 is _{accidentally), (NH 2 CH = NH} 2 (1-x) CH 3 NH 3x) 2 InSb (I (1-y) Br y) 6 (0.05≤x≤0.5 mistake, 0.05≤y≤0.5 the real and x + y = 1), ( NH 2 CH = CH 2 (1-x) CH 3 NH 3x) 2 InSb (I (1-x) Br _x ) ₆ (x is a real number of 0.05? X? 0.5), (NH ₂ C (CH ₃ ) = NH ₂ ) ₂ InSb (I _x Cl _y ) ₆ (0? _X ? 1, 1), (NH ₂ C (CH ₃ ) NH ₂ ) ₂ InSb (I _x Br _y ) ₆ (0 ≤ x ≤ 1, 0 _{≤ y ≤} 1, and x x y = 1), (NH ₂ C (CH ₃ ) = NH ₂ ) ₂ InSb (I _x Br _y ) ₆ (real number 0.5 ≦ _x ≦ 0.95, real number 0.05 ≦ _y ≦ 0.5, _{, (NH 2 C (CH 3} ) = NH 2) 2 InSb (Cl x Br y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 C _{(CH 3) = NH 2)} 2 InSb (I x F y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 C (CH 3) = _{NH 2 (1-x) CH} 3 NH 3x) 2 InSb (I (1-y) Br y) 6 (x is in 0 <x <1 real number, y is 0 <y <1 is accidentally), (NH _{2 C (CH 3) = NH} 2 (1-x) CH 3 NH 3x) _{2 InSb (I (1-y} ) Br y) 6 (x is a real number of 0.05≤x≤0.5, y is a real number _{0.05≤y≤0.5), (NH 2 C (CH} 3) = CH 2 (1- _{x) CH 3 NH 3x) 2} InSb (I (1-x) Br x) 6 (x is a real _{0.05≤x≤0.5), (NH 2 C (NH} 2) = NH 2) 2 InSb (I x Cl _{y) 6} (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 C (NH 2) = NH 2) 2 I x Br y (InSb) 6 (0 Y? 1 and x + y = 1), (NH ₂ C (NH ₂ ) = NH ₂ ) ₂ InSb (I _x Br _y ) ₆ (0.5? _X? mistake, 0.05≤y≤0.5 the real and x + y = 1), ( NH 2 C (NH 2) = NH 2) 2 InSb (Cl x Br y) 6 (0≤x≤1 mistake, 0≤y ≤1 is a real number and x + y = 1), ( NH 2 C (NH 2) = NH 2) 2 InSb (I x F y) 6 (0≤x≤1 mistake, 0≤y≤1 real and x + y = 1), ( NH 2 C (NH 2) = NH 2 (1-x) CH 3 NH 3x) 2 InSb (I (1-y) Br y) 6 (x is in 0 <x <1 mistake and, y is 0 <y <1 is _{accidentally), (NH 2 C (NH} 2) = NH 2 (1-x) CH 3 NH 3x) 2 InSb (I (1-y) Br y) 6 (x is a real number of 0.05≤x≤0.5, y is a real number 0.05≤y≤0.5) or _{(NH 2 C (NH 2)} = CH 2 (1-x) CH 3 NH 3x) 2 InSb (I (1-x ₎ Br _x ) ₆ (x is A real number of 0.05? X? 0.5).

On the basis of the above description, one example of a specific, non-limiting perovskite compound in which the monovalent metal ion is In ¹⁺ and the trivalent metal ion is Bi ³⁺ is a perovskite compound (CH _{3 NH 3) 2 InBi (I} x Cl y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( CH 3 NH 3) 2 InBi (I x Br y ) ₆ (0≤x≤1 mistake, 0≤y≤1 of the real and x + y = 1), ( CH 3 NH 3) 2 InBi (Cl x Br y) 6 (0≤x≤1 real number, 0≤y≤1 the real and x + y = 1), ( CH 3 NH 3) 2 InBi (I x F y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y _{= 1), (NH 2 CH} = NH 2) 2 InBi (I x Cl y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 CH = _{NH 2) 2 InBi (I x} Br y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 CH = NH 2) 2 InBi (I x Br _{y) 6} (0.5≤x≤0.95 mistake, 0.05≤y≤0.5 the real and x + y = 1), ( NH 2 CH = NH 2) 2 InBi (Cl x Br y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 CH = NH 2) 2 InBi (I x F y) 6 (0≤x≤1 Real number, the real number 0≤y≤1 and x + y = 1), ( NH 2 CH = NH 2 (1-x) CH 3 NH 3x) 2 InBi (I (1-y) Br y) 6 (x is and the 0 <x <1 real number, y is 0 <y <1 is _{accidentally), (NH 2 CH = NH} 2 (1-x) CH 3 NH 3x) 2 InBi (I (1-y) Br y) 6 (0.05≤x≤0.5 mistake, 0.05≤y≤0.5 the real and x + y = 1), ( NH 2 CH = CH 2 (1-x) CH 3 NH 3x) 2 InBi (I (1-x) Br _x ) ₆ (x is a real number with 0.05? X? 0.5), (NH ₂ C (CH ₃ ) = NH ₂ ) ₂ InBi (I _x Cl _y ) ₆ (0? _X ? 1, 1), (NH ₂ C (CH ₃ ) NH ₂ ) ₂ InBi (I _x Br _y ) ₆ (real number of 0? X? 1, real number of 0? _Y ? 1, and x + y = 1), (NH 2 C (CH 3) = NH 2) 2 InBi (I x Br y) 6 (0.5≤x≤0.95 mistake, 0.05≤y≤0.5 the real and x + y = 1) _{, (NH 2 C (CH 3} ) = NH 2) 2 InBi (Cl x Br y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 C _{(CH 3) = NH 2)} 2 InBi (I x F y) 6 (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 C (CH 3) = _{NH 2 (1-x) CH} 3 NH 3x) 2 InBi (I (1-y) Br y) 6 (x is in 0 <x <1 real number, y is 0 <y <1 is accidentally), (NH _{2 C (CH 3) = NH} 2 (1-x) CH 3 NH 3x) _{2 InBi (I (1-y} ) Br y) 6 (x is a real number of 0.05≤x≤0.5, y is a real number _{0.05≤y≤0.5), (NH 2 C (CH} 3) = CH 2 (1- _{x) CH 3 NH 3x) 2} InBi (I (1-x) Br x) 6 (x is a real _{0.05≤x≤0.5), (NH 2 C (NH} 2) = NH 2) 2 InBi (I x Cl _{y) 6} (0≤x≤1 mistake, 0≤y≤1 the real and x + y = 1), ( NH 2 C (NH 2) = NH 2) 2 I x Br y (InBi) 6 (0 X N y = 1), (NH ₂ C (NH ₂ ) = NH ₂ ) ₂ InBi (I _x Br _y ) ₆ (0.5? _X? Real number, real number of 0.05? Y? 0.5 and x + y = 1), (NH ₂ C (NH ₂ ) = NH ₂ ) ₂ InBi (Cl _x Br _y ) ₆ 1) and (NH ₂ C (NH ₂ ) = NH ₂ ) ₂ InBi (I _x F _y ) ₆ (real number of 0? _X ? 1, real number of 0? _Y ? x + y = 1), ( NH 2 C (NH 2) = NH 2 (1-x) CH 3 NH 3x) 2 InBi (I (1-y) Br y) 6 (x is in 0 <x <1 mistake and, y is 0 <y <1 is _{accidentally), (NH 2 C (NH} 2) = NH 2 (1-x) CH 3 NH 3x) 2 InBi (I (1-y) Br y) 6 (x is a real number of 0.05≤x≤0.5, y is a real number 0.05≤y≤0.5) or _{(NH 2 C (NH 2)} = CH 2 (1-x) CH 3 NH 3x) 2 InBi (I (1-x ₎ Br _x ) ₆ (x is A real number of 0.05? X? 0.5).

The perovskite compound according to one embodiment of the present invention can be prepared by using the crystallization property of the perovskite compound by self-assembly. Specifically, a solution (hereinafter, a perovskite solution) is prepared by dissolving an organic halide and a metal halide in a solvent so as to satisfy formulas (1) to (4) including the above specific examples, &Lt; / RTI &gt; At this time, it is possible to maintain the completely dissolved state by heating using the change of solubility according to temperature, but it is of course possible to cause precipitation by supersaturation upon cooling. In detail, the perovskite compound according to one embodiment of the present invention can be prepared by reacting a mixed solution of an aqueous solution of hydrobromic acid (HBr) and an aqueous solution of a solution of hydrofluoroacetic acid in an organic halide And a precursor of a metal halide, and then heating the resultant at 100 to 140 ° C, specifically 110 to 130 ° C, and cooling the perovskite compound to precipitate the perovskite compound. In this case, the heating time may be 5 to 15 minutes, but is not limited thereto. The volume ratio of the aqueous hydrobromic acid solution to the hypophosphoric acid aqueous solution may be 1: 0.1 to 0.4, the aqueous hydrobromic acid solution may contain 30 to 55 wt% of hydrobromic acid, and the aqueous hypophosphoric acid solution may contain 40 to 60 wt% It may contain phosphorous acid. Also, the precursor contained in the mixed solution may be 0.0005 mol to 0.002 mol based on the perovskite compound represented by the general formulas (1) to (4).

The present invention includes an electronic element, an optical element, a memory element, a thermoelectric element or a sensor including the above-mentioned perovskite compound.

The electronic device includes a transistor, and the optical device includes a light emitting device including a light emitting diode or a laser, a photodetector (photosensor) or a photovoltaic device (solar cell), and the memory device includes a volatile or nonvolatile memory device And the sensor includes a detection sensor for detecting an organic compound or a biochemical material.

For example, the present invention is based on the structure of a first electrode, an n-type semiconductor (electron carrier), a light emitting layer, a p-type semiconductor (hole carrier), and a second electrode, which are the basic structures of a light emitting diode, And a light emitting layer containing a light emitting layer containing the light emitting layer.

For example, the present invention includes a resistance change type memory having a semiconductor containing a perovskite compound as described above based on the structure of a first electrode-semiconductor-second electrode which is a basic structure of a resistance change type memory. As is well known, the first electrodes may be metal strips spaced apart from each other in one direction, and the second electrode may be metal strips spaced apart from each other in one direction so as to be orthogonal to the metal strips of the first electrode. have.

For example, the present invention relates to a semiconductor device having a structure of a gate located above or below a semiconductor channel with a semiconductor channel located between a source and drain and a source and a drain opposing to each other, But includes a transistor having a semiconductor channel containing the above-mentioned perovskite-based compound.

As described above, a person skilled in the related art, such as an electronic device such as a transistor, a light emitting device that generates light, a memory device, a thermoelectric device, or a photovoltaic device (solar cell) It is obvious that the device can be implemented by designing and modifying the component containing the above-mentioned perovskite compound in accordance with the device.

Among various applications of perovskite compounds, application to commercially important solar cells is described in more detail.

The present invention includes a solar cell containing the above-mentioned perovskite compound as a light absorber.

A solar cell according to an embodiment of the present invention includes a first electrode, a first charge carrier disposed on the first electrode, a light absorber including the above-described perovskite compound on the first charge carrier, And a second electrode positioned on the second charge transfer body.

The first electrode may be on a substrate, and the substrate may be a rigid substrate or a flexible substrate. As a specific example, the substrate may be a rigid substrate or a polyethylene terephthalate (PET) film including a glass substrate; Polyethylene naphthalate (PEN): polyimide (PI); Polycarbonate (PC); Polypropylene (PP); Triacetylcellulose (TAC); Polyether sulfone (PES), and the like. However, it goes without saying that the present invention can not be limited by the kind of the substrate.

The first electrode may be a conductive electrode to be ohmic-bonded to the first charge carrier, and may be a material commonly used as an electrode material of a front electrode or a rear electrode in a solar cell. In a non-limiting example, when the first electrode is an electrode material of the rear electrode, the first electrode may be formed of one of gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, Or more. In a non-limiting example, when the first electrode is a transparent electrode, the first electrode may include a fluorine-containing tin oxide (FTO), indium doped tin oxide (ITO), ZnO, CNT Nanotubes), graphene, and the like, and may be organic-based conductive electrodes such as PEDOT: PSS. In the case of providing a transparent solar cell, it is preferable that both the electrode (the first electrode and the second electrode) and the substrate are both a transparent electrode and a transparent substrate. When the electrode (the first electrode or the second electrode) is an organic conductive electrode, it is preferable to provide a flexible solar cell or a transparent solar cell.

The first charge carrier positioned above the first electrode may prevent direct contact between the first electrode and the light absorber and may provide a path for movement of charges of photoelectrons or photo holes generated in the light absorber. At this time, the first charge carrier and the second charge carrier can transfer complementary charges. For example, when the first charge carrier is an electron transferring material, the second charge carrier may be a hole transporting material, and when the first charge carrier is hole transporting, the second charge carrier may be an electron carrier.

Hereinafter, a solar cell according to an example of the present invention is described based on the case where the first charge carrier is an electron transferring material, and when the first charge carrier is a hole transferring material, the first charge carrier is a It is of course possible to have the same or similar configuration as the contents.

The electron carrier may be an electron conductive organic layer or an inorganic layer. The electron conductive organic material may be an organic material used as an n-type semiconductor in a conventional organic solar cell. (6,6] -phenyl-C61 butyric acid methyl ester), and C71-PCBM, C7-PCBM, and C7-PCBM, C84-PCBM, PC ₇₀ BM fullerene containing _{([6,6] -phenyl C 70 -butyric} acid methyl ester) - derivatives (Fulleren-derivative), PBI ( polybenzimidazole), PTCBI (3,4,9,10- perylenetetracarboxylic bisbenzimidazole, F4-TCNQ (tetrauorotetracyanoquinodimethane), or mixtures thereof.

The electron conductive inorganic material may be an electron conductive metal oxide used for electron transfer in a conventional quantum dot-based solar cell or a dye-sensitized solar cell. As a specific example, the electron conductive metal oxide may be an n-type metal oxide semiconductor. Examples of the n-type metal oxide semiconductor include Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Ba oxide, Zr oxide, Sr oxide, Yr oxide, La One or more materials selected from oxides, V oxides, Al oxides, Y oxides, Sc oxides, Sm oxides, Ga oxides, In oxides and SrTi oxides, and mixtures or composites thereof have.

In the structure, the electron carrier may be a porous layer (porous membrane) or a dense layer (dense membrane). The dense electron carrier may be a film of the above-mentioned electron conductive organic material or a dense film of the electron conductive inorganic material. The porous electron carrier may be a porous film composed of particles of the above-described electron conductive inorganic material. The thickness of the electron transporting material may be 50 nm to 10 μm, specifically 50 nm to 1000 nm. When the electron transporting material is porous, its specific surface area may be 10 to 100 m ² / g, and the average particle diameter of the metal oxide particles constituting the electron transporting material may be 5 to 500 nm. The porosity (apparent porosity) of the porous electron carrier may be 30% to 65%, specifically 40% to 60%.

When the electron transporting material is a porous structure, an electron transporting film may be further provided between the first electrode and the electron transporting material. The electron transporting film may prevent the direct contact between the light absorber and the first electrode, and may transfer electrons. The electron transport membrane may be a material that can move electrons spontaneously from the porous metal oxide to the first electrode through the electron transport membrane on the energy band diagram. As a nonlimiting and specific example, the electron transporting film may be a metal oxide thin film, and the metal oxide of the metal oxide thin film may be the same or different from the metal oxide of the porous metal oxide. In detail, the material of the metal oxide thin film may be Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Ba oxide, Zr oxide, Sr oxide, Yr oxide, La oxide, , Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, In oxide, SrTi oxide, ZnSn oxide, a mixture thereof, and a combination thereof. The thickness of the electron transporting film may be substantially 10 nm or more, more practically 10 nm to 100 nm, and more practically 50 nm to 100 nm.

When the electron transporting material is a porous layer (porous film), the light absorber positioned on the electron transporting material may be a particle image attached to the electron transporting material, similar to the dye of the dye-sensitized solar cell, And may have a structure of a dense film or a porous film covering the electron transporting body. At this time, the porous film may include an island structure in which the film forming grains are not continuously connected to each other. When the structure in which the pores of the porous electron carrier are filled with the perovskite compound is referred to as a composite layer, the protruding structure formed of the perovskite compound and protruding to the upper side of the composite layer may also fall within the category of the porous membrane have. The structure of such a protruding structure (pillar structure), a dense film or a porous film covering the multiple layer and the multiple layer is disclosed in Applicants' Publication Nos. 2014-0035285, 2014-0035284 or 2014-0035286 It is to be appreciated that the present invention entirely includes the features described in the published patents 2014-0035285, 2014-0035284 or 2014-0035286, including the proposed structure.

In the case where the electron carrier is a dense layer, the light absorbing layer may be a dense film, a porous film, or a laminated film thereof located above the electron transporting body.

The thickness of the light absorbing layer of the dense film or the porous film can be appropriately adjusted in consideration of the amount or thickness of the light absorber (or light absorbing layer) designed in the solar cell. As a specific, non-limiting example, the thickness of the light absorbing layer (thickness of the film covering the top of the electron transporting material) located on the electron transporting material may be between 1 nm and 10 μm.

The light absorber (or light absorption layer) can be produced by a conventional solution coating method or a two-step coating method in which the non-solvent is applied again after solution application. A more detailed solution coating method or a two-step coating method can be found in the applicants' published patents 2014-0035285, 2014-0035284 or 2014-0035286.

The second charge carrier may be a hole transporting material, and the hole transporting material may be an organic hole transporting material, an inorganic hole transporting material, or a laminate thereof.

When the hole transporting material includes an inorganic hole transporting material, the inorganic hole transporting material may be an oxide semiconductor, a sulfide semiconductor, a halide semiconductor, or a mixture thereof having a hole conductivity, that is, a p-type semiconductor.

Examples of the oxide semiconductor include NiO, CuO, CuAlO ₂ , and CuGaO _2. Examples of the sulfide semiconductor include PbS and examples of the halide semiconductor include PbI _2. However, the present invention is not limited thereto But is not limited thereto.

The hole transporting material may be a dense layer (dense film). A dense hole carrier is a dense film of the above-described p-type semiconductor. The thickness of the inorganic hole carrier may be 50 nm to 10 μm, specifically 10 nm to 1000 nm, more specifically 50 nm to 1000 nm.

When the hole transporting material includes an organic hole transporting material, the organic hole transporting material may include an organic hole transporting material, specifically, a monomolecular or polymer organic hole transporting material (hole transporting organic material). The organic hole transport material can be used as an organic hole transport material used in a conventional inorganic semiconductor based solar cell using an inorganic semiconductor quantum dot as a dye, and a polymer organic hole transport material is preferable from the standpoint of stability.

Non-limiting examples of monomolecular or low molecular organic hole transport materials include pentacene, coumarin 6, 3- (2-benzothiazolyl) -7- (diethylamino) coumarin, ZnPC (zinc phthalocyanine) copper phthalocyanine, titanium oxide phthalocyanine (TiOPC), Spiro-MeOTAD (2,2 ', 7,7'-tetrakis (N, Np-dimethoxyphenylamino) -9,9'- spirobifluorene), F16CuPC , 31H-phthalocyanine, SubPc (boron subphthalocyanine chloride), and N3 (cis -di (thiocyanato) -bis (2,2'-bipyridyl-4,4'-dicarboxylic acid) -ruthenium (II)).

The organic hole-transporting material is preferably a polymer (hole-conducting polymer) in terms of stability. The hole-conducting polymer includes one or more selected from thiophene, paraphenylene vinylene, carbazole and triphenylamine In consideration of energy matching, one or two or more thiophene-based compounds and triphenylamine-based compounds may be selected, more preferably triphenylamine-based ones. Non-limiting examples of the polymer organic hole transport material include poly [3-hexylthiophene] (P3HT), poly [2-methoxy-5- (3 ', 7'- dimethyloctyloxyl)] - 1,4-phenylene poly (3-octyl thiophene), POT (poly (octyl thiophene)), poly (vinylidene fluoride), polyvinylene, MEH-PPV Poly (3-decyl thiophene), poly (3-dodecyl thiophene), poly (p-phenylene vinylene), poly (9,9'-dioctylfluorene- butylphenyl) diphenyl amine), Polyaniline, Spiro-MeOTAD ([2,22 ', 7,77'-tetrkis (N, N-di-p- methoxyphenyl amine) (Poly [2,1,3-benzothiadiazole-4,7-diyl4,4-bis (2-ethylhexyl-4H-cyclopenta [ dl]], Si-PCPDTBT (poly [(4,4'-bis (2-ethylhexyl) dithieno [3,2-b: 2 ', 3'- 2,1,3-benzothiadiazole) -4,7-diyl]), PBDTTPD (poly ((4,8-diethylhexyloxyl) benzo [1,2- b: 4,5-b '] dithiophene) -1,3-diyl)), PFDTBT (poly [2,7- (9- (2-ethylhexyl) ) -9 -hexyl-fluorene) -tallow-5,5- (4 ', 7 -di-2-thienyl-2', 1 ', 3'-benzothiadiazole)], PFO-DBT (poly [2,7-. 5 '- (4', 7'-di-2-thienyl-2 ', 1', 3'-benzothiadiazole)]), PSiFDTBT (poly [ , 7-dioctylsilafluorene) -2,7-diyl-lower- (4,7-bis (2-thienyl) -2,1,3-benzothiadiazole) -5,5'-diyl], PSBTBT (poly [ , 4'-bis (2-ethylhexyl) dithieno [3,2-b: 2 ', 3'-d] silole) -2,6-diyl-6- (2,1,3-benzothiadiazole) 2,6-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2 , 5-thiophenediyl], PFB (poly (9,9'-dioctylfluorene-co-bis (N, N ' , Poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate), PTAA (poly (3,4-ethylenedioxythiophene), PEDOT (triarylamine), poly (4-butylphenyl-diphenyl-amine), and copolymers thereof. As a non-limiting and specific example, the hole transporting material may be a thin film of an organic hole transporting material, and the thickness of the thin film may be 10 nm to 500 nm.

It is needless to say that the organic hole transporting material may further include an additive conventionally used for improving properties such as conductivity improvement of an organic material-based hole conduction layer in an inorganic semiconductor-based solar cell using a conventional inorganic semiconductor quantum dot as a dye. As a non-limiting example, the hole transporting material may be either one or two of TBP (tertiary butyl pyridine), LiTFSI (Lithium Bis (Trifluoro methanesulfonyl) Imide) and Tris (2- (1H- pyrazol- Or more, and may contain 0.05 mg to 100 mg of an additive per 1 g of the organic hole transporting material. However, it goes without saying that the present invention can not be limited by the presence / absence of the additive, the kind of the additive, and the content of the additive in the hole transporting material.

The second electrode may be a conductive electrode that is ohmic-bonded to the hole transporting material, and may be used as a material commonly used as an electrode material of a front electrode or a rear electrode in a solar cell. In a non-limiting example, when the second electrode is an electrode material of the rear electrode, the second electrode may be formed of gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, Or a combination thereof. In a non-limiting example, when the second electrode is a transparent electrode, the second electrode may include a fluorine-containing tin oxide (FTO), indium doped tin oxide (ITO), ZnO, CNT Nanotubes) and graphene, and may be organic-based conductive electrodes such as PEDOT: PSS. In the case of providing a transparent solar cell, the second electrode is preferably a transparent electrode, and when the second electrode is an organic conductive electrode, it is preferable to provide a flexible solar cell or a transparent solar cell.

The energy band structure and the electron state density of a monovalent organic cation having a double perovskite structure, a perovskite compound of a monovalent metal ion, a trivalent metal ion, and a halogen ion are quantitatively analyzed by a first quantum mechanical principle The results were analyzed by applying the calculation. At this time, it is assumed that the atomic nuclei are relatively fixed according to the Born-Oppenheimer approximation, and the interaction between electrons and electrons is represented by the Kohn-Sham equation and the density function theory (DFT) Funtional Theory) was used for the analysis. At this time, Cs ⁺ is used as an organic cation, and it is already known that the energy band structure is hardly affected by the organic cation.

FIG. 1 is a diagram showing an energy band structure of Cs ₂ InSbI ₆ and Cs ₂ InSbBr ₆ , FIG. 2 is a diagram showing an energy band structure of Cs ₂ InBiI ₆ and Cs ₂ InBiBr ₆ , 3, Cs ₂ is a view showing an energy band structure of CuInI _6, Fig. 4 is a view showing an energy band structure of Cs ₂ AgInI ₆ and Cs ₂ AgInBr _6, Figure 5 is Cs ₂ AgGaI ₆ and Cs ₂ AgGaBr ₆ And Fig.

As can be seen from FIGS. 1 to 5, it can be seen that a direct transition bandgap capable of absorbing light extremely effectively is formed, and that it has a band gap energy suitable for solar absorption.

Table 1 shows the page as a lobe Sky teugye the energy band gap (E _G), electron effective mass (m * _elec) and the hole effective mass (m * _hole) organized by the compounds shown, presented as a CsPbI ₃ as a comparative example.

(Table 1)

As can be seen from FIGS. 1 to 5 and Table 1, when In ^{1 +} is contained as a monovalent metal ion, VBM (valance band maximum) is mainly caused by a hybrid of the s-orbital of In and the p- orbital of a halogen anion And has a spherical wave-function shape with an angular momentum of zero, it can have an isotropic and highly dispersive VBM. By such VBM, perovskite-based compounds containing In as a monovalent metal ion can have a remarkably small hole-effective mass.

The CBM (conduction band maximum) is mainly formed by the p-orbital of the trivalent metal ion and the p-orbital hybrid of the halogen ion. When the trivalent metal ion is Sb or Bi, the size of the spin-orbit coupling (SOC) of Sb or Bi is large and a more isotropic and highly discursive CBM is formed. By this CMB, the perovskite- It can have a significantly smaller electron effective mass.

As described above, in the case of a perovskite compound containing In ⁺ -Sb ³⁺ and In ⁺ -Bi ³⁺ as a metal ion pair, a significantly smaller hole effective mass and electron effective mass reaching 10 ^-2 order And has a bandgap which is very effective for solar absorption and can have similar or better photoelectric properties than conventional lead-based perovskite compounds. In the case of a perovskite compound containing Ag ⁺ -In ³⁺ , Cu ⁺ -In ³⁺ , and Ag ⁺ -Ga ³⁺ as a metal ion pair, a perovskite compound, which is almost similar to a conventional lead-based perovskite compound It is possible to effectively replace the lead-based perovskite compound with an effective mass and an electron effective mass and a band gap favorable for solar absorption.

_{Cs 2 AgBiX 6, Cs 2 AuBiX} 6, Cs 2 CuBiX 6, Cs 2 CuSbX 6, Cs 2 AgSbX 6, Cs 2 AuSbX 6, Cs 2 SbBiX 6, Cs 2 AgAuX 6 (X is I, Cl or Br) including, In the case of a bimetallic ion-based perovskite compound deviating from the scope of the present invention, it has an indirect transitional bandgap structure and is unsuitable as a light absorber or has a very large effective charge (electron and / or hole) It is difficult to replace the lead-based perovskite compound.

[Example 1] Preparation of Cs ₂ InSbBr ₂ I ₄ double perovskite

Hydrobromic acid (HBr) 48 wt% aqueous solution 8 ㎖ and hypophosphite _{(H 3 PO 2) CsBr 0.426} g (0.002 mol) so as to satisfy the Cs ₂ InSbBr ₂ I ₄ to 50% by weight aqueous solution of 2 ㎖ mixture, InI 0.242 g ( 0.001 mol) and 0.502 g (0.001 mol) of SbI ₃ were added in this order to prepare a precursor solution.

The prepared precursor solution was heated to 120 DEG C to dissolve all of the precursors and heated for an additional 10 minutes. When the precursor solution that has been reacted is cooled to room temperature, it can be confirmed that a precipitate is formed. The precipitate was recovered and the X-ray diffraction pattern was analyzed to confirm the double perovskite phase.

[Example 2] Preparation of Cs ₂ InBiBr ₅ I double perovskite

0.242 g (0.001 mol) of CIbr, 0.242 g (0.001 mol) of InI and 0.449 g (0.001 mol) of BiBr ₃ were added to 8 ml of a 48 wt% aqueous solution of hydrobromic acid (HBr) and 50 wt% aqueous solution of hypophosphoric acid (H ₃ PO ₂ ) Ml &lt; / RTI &gt;

The mixed solution was heated to 120 DEG C to dissolve all of the precursors and heated for an additional 10 minutes. When the solution is cooled to room temperature, it is confirmed that the precipitate is formed. The precipitate was recovered and the X-ray diffraction pattern was analyzed to confirm the double perovskite phase.

[Example 3] Preparation of Cs ₂ CuInBr ₂ I ₄ double perovskite

CsBr 0.426 g (0.002 mol), CuI 0.190 g (0.001 mol), InI 3 0.496 g (0.001 mol) of hydrobromic acid (HBr) 48 wt% aqueous solution 8 ㎖ and hypophosphite (H ₃ PO ₂₎ 50% by weight aqueous solution of 2 Ml &lt; / RTI &gt;

The mixed solution was heated to 120 DEG C to dissolve all of the precursors and heated for an additional 10 minutes. When the solution is cooled to room temperature, it is confirmed that the precipitate is formed. The precipitate was recovered and the X-ray diffraction pattern was analyzed to confirm the double perovskite phase.

[Example 4] Preparation of Cs ₂ AgInBr ₃ I ₃ double perovskite

CsBr 0.426 g (0.002 mol), AgBr 0.188 g (0.001 mol), InI 3 0.496 g (0.001 mol) of hydrobromic acid (HBr) 48 wt% aqueous solution 8 ㎖ and hypophosphite (H ₃ PO ₂₎ 50% by weight aqueous solution of 2 Ml &lt; / RTI &gt;

The mixed solution was heated to 120 DEG C to dissolve all of the precursors and heated for an additional 10 minutes. When the solution is cooled to room temperature, it is confirmed that the precipitate is formed. The precipitate was recovered and the X-ray diffraction pattern was analyzed to confirm the double perovskite phase.

[Example 5] Preparation of Cs ₂ AgGaBr ₆ double perovskite

CsBr 0.426 g (0.002 mol), AgBr 0.188 g (0.001 mol), GaBr 3 0.309 g (0.001 mol) of hydrobromic acid (HBr) 48 wt% aqueous solution 8 ㎖ and hypophosphite (H ₃ PO ₂₎ 50% by weight aqueous solution of 2 Ml &lt; / RTI &gt;

The mixed solution was heated to 120 DEG C to dissolve all of the precursors and heated for an additional 10 minutes. When the solution is cooled to room temperature, it is confirmed that the precipitate is formed. The precipitate was recovered and the X-ray diffraction pattern was analyzed to confirm the double perovskite phase.

[Example 6]

A perovskite solar cell including the double perovskite material prepared in Example 1 was prepared, and a perovskite solar cell was manufactured using a conventional method.

a) Preparation of porous TiO ₂ thin film substrate

A glass substrate (FTO: F-doped SnO 2, 8 ohms / cm 2, Pilkington, hereinafter referred to as FTO substrate (first electrode)) coated with fluorine-containing tin oxide was cut into a size of 25 x 25 mm, To remove the FTO.

On the cut and partially etched FTO substrate, a TiO2 compact film with a thickness of 50 nm was fabricated by spray pyrolysis as a metal oxide thin film. Spray pyrolysis was carried out using a solution of titanium acetylacetonate (TAA): EtOH (1: 9 v / v%), spraying for 3 seconds on the FTO substrate placed on a hot plate kept at 450 ° C and stopping for 10 seconds The thickness was adjusted by the method.

TiO ₂ powder having an average particle size (diameter) of 50 nm (prepared by hydrothermally treating titanium peroxocomplex aqueous solution of 1 wt% based on TiO ₂ dissolved therein at 250 ° C for 12 hours) was mixed with 10% by weight of ethyl cellulose acetate the ethyl cellulose solution in an alcohol, then a solution was added 5 ml per TiO ₂ powder 1g, adding the hotel pinol (terpinol) 5 g per 1 g TiO ₂ powder, and the ethanol removed by vacuum distillation TiO ₂ Paste.

To the TiO ₂ powder paste thus prepared, ethanol was added (1 (TiO ₂ powder paste): 5 (ethanol) weight ratio) to prepare a TiO ₂ slurry for spin coating. (3000 rpm) using a TiO ₂ slurry for spin coating on a TiO ₂ thin film of an FTO substrate and heat-treated at 500 ° C. for 60 minutes. Subsequently, the heat-treated substrate was immersed in a 30 mM aqueous solution of TiCl ₄ at 60 ° C. , Left for 30 minutes, washed with deionized water and ethanol, dried, and then heat-treated at 500 ° C for 30 minutes to prepare a porous TiO ₂ thin film (porous electron transport material). At this time, the thickness of the porous TiO ₂ thin film (porous electron carrier) was 100 nm, the specific surface area of the prepared porous electron carrier was 33 m ² / g, and the porosity (apparent porosity) was 50%.

b) Preparation of a double perovskite halide solution

The Cs ₂ InSbBr ₂ I ₄ solution at a concentration of 0.8 M was prepared by using a mixed solvent obtained by mixing gamma-butylolactone and dimethylsulfoxide in a volume ratio of 7: 3 as a solvent, and adding Cs ₂ InSbBr ₂ I ₄ powder.

c) Manufacture of solar cells

The above prepared Cs ₂ InSbBr ₂ I ₄ solution was applied (injected) onto the porous TiO ₂ thin film substrate (FTO / TiO ₂ substrate) prepared above, and spin-coated at 3000 rpm. When the spin-coating time was 50 seconds, 1 ml of toluene was added to the center of rotation of the FTO substrate under spinning, and spin coating was further performed for 5 seconds. After the spin coating was performed, annealing was performed at a temperature of 150 ° C and normal pressure for 30 minutes to form a perovskite compound film (light absorbing layer), which is a perovskite light absorber.

Thereafter, a toluene solution [15 mg (PTAA) / 1 ml] in which PTAA (poly (triarylamine), EM index, Mw = 17,500 g / mol) was spin-coated at 3000 rpm for 60 seconds, Layer. At this time, 2.31 mg of LiTFSI (Lithium Bis (Trifluoro methanesulfonyl) Imide) and 6.28 mg of TBP (tertiary butyl pyridine) were added to the PTAA solution.

Thereafter, an Au electrode (second electrode) having a thickness of 70 nm was formed on the hole transporting layer by vacuum evaporation of Au with a thermal evaporator of a high vacuum (5 × 10 ^-6 torr or less) to produce a solar cell . In the manufacture of the solar cell, the ambient environment maintained a temperature of 25 ° C and a relative humidity of 25%.

In order to measure the current-voltage characteristics of the manufactured perovskite solar cell, an artificial solar device (ORIEL class A solar simulator, Newport, model 91195A) and a source-meter (Kethley, model 2420) , And it was measured under a standard test condition of 1,000 W / ㎡ of sunlight intensity and constant temperature of 25 캜. As a result, the photovoltaic conversion parameters of the perovskite solar cell showed a short circuit current density Jsc of 7.8 mA / cm 2, an open circuit voltage Voc of 0.96 V, a performance index FF of 71.2%, and a photoelectric conversion efficiency of 5.3%.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (7)

A perovskite compound having a direct band gap and satisfying the formula (1) and containing no lead.
(Formula 1)
A ₂ (M ^I M ^III ) X ₆
(Wherein A is a monovalent cation, A is at least one selected from an alkali ion, an organic ammonium ion and an amidinium group ion, M ¹ is a monovalent metal ion, M ^III is a trivalent cation, Metal ion, and X is a halogen ion) The method according to claim 1,
The perovskite compound is a perovskite compound having a double perovskite structure. 3. The method of claim 2,
Wherein the M ^I is In ^+, or the M ^III is In ³⁺ or Ga ³⁺ . The method of claim 3,
Wherein said M ^I -M ^III pair is i) to vi).
i) In ¹⁺ -Sb ³⁺
ii) In ¹⁺ -Bi ³⁺
v) Cu ¹⁺ -In ³⁺
iv) Ag ¹⁺ -In ³⁺
v) Ag ¹⁺ -Ga ³⁺ The method of claim 3,
A perovskite compound having a band gap energy of 1 to 2.5 eV. The method of claim 3,
Wherein X is one or more selected from I ^- , Br ^- and Cl ^- . A solar cell comprising a perovskite compound according to any one of claims 1 to 6 as a light absorber.

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