KR102404027B1 - Perovskite Compound Having Improved Stability - Google Patents

Abstract

The organic-inorganic perovskite compound according to the present invention contains an amidinium-based monovalent cation, an alkylammonium-based monovalent cation and an alkylenediammonium-based divalent cation as an organic cation, and an inorganic cation, a divalent metal It contains an ion and an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion, and contains a halogen ion as an inorganic anion.

Description

Organic-inorganic perovskite compound having improved stability {Perovskite Compound Having Improved Stability}

The present invention relates to an organic-inorganic perovskite compound having improved stability, and more particularly, to an organic-inorganic perovskite compound having improved thermal stability, moisture stability and light stability, and excellent photoelectric conversion efficiency.

Organometallic halide of perovskite structure, also referred to as organic-inorganic perovskite compound or organometal halide perovskite compound, is an organic cation (A), a metal cation (M) and a halogen anion. It consists of (X), and is a substance represented by the chemical formula of AMX ₃ .

Currently, perovskite solar cells using organic/inorganic perovskite compounds as light absorbers are the closest to commercialization among next-generation solar cells including dye-sensitized and organic solar cells, and have reported efficiencies of up to 20% (Korea Patent Publication No. 2014-0035284), and interest in organic/inorganic perovskite compounds is increasing.

These organic/inorganic perovskite compounds have very low material prices, and have excellent commercial properties because low-temperature processes or low-cost solution processes are possible. Accordingly, there is a need for technology development for organic-inorganic perovskite compounds having high stability and improved efficiency.

Currently, the organic-inorganic perovskite compound exhibiting the best photoelectric conversion efficiency is an amidinium-based perovskite compound containing an amidinium-based cation as an organic cation. However, the amidinium-based perovskite compound is less stable than other perovskite compounds, and for the actual commercialization of perovskite solar cells with excellent efficiency, the stability of the amidinium-based perovskite compound It is essential to develop technologies to improve

Republic of Korea Patent Publication No. 2014-0035284

The present invention is to provide an amidinium-based organic-inorganic perovskite compound having excellent stability and improved efficiency.

The organic-inorganic perovskite compound according to an aspect of the present invention contains an amidinium-based monovalent cation, an alkylammonium-based monovalent cation and an alkylenediammonium-based divalent cation as an organic cation, and is an inorganic cation, It contains a divalent metal ion and an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion, and contains a halogen ion as an inorganic anion.

The organic-inorganic perovskite compound according to another aspect of the present invention is a base material and a dopant doped to the base material of the following Chemical Formula 1, an organic dopant of an alkylenediammonium divalent cation and 0.8 based on an ionic radius of M in Chemical Formula 1 and an inorganic dopant of an alkali metal ion having an ionic radius of from 1.3.

(Formula 1)

A' _x A'' _1-x MX ₃

A' is a monovalent amidinium cation, A'' is a monovalent organic ammonium cation, M is a divalent metal ion, X is a halogen anion, and x is a real number such that 0<x<1.

In the organic-inorganic perovskite compound according to an embodiment of the present invention, the alkali metal ion may include K ⁺ .

In the organic-inorganic perovskite compound according to an embodiment of the present invention, the alkylenediammonium-based divalent cation may be a C1-C12 alkylenediammonium cation.

The organic-inorganic perovskite compound according to an embodiment of the present invention may contain 0.001 to 0.020 moles of alkali metal ions based on 1 mole of divalent metal ions.

In the organic-inorganic perovskite compound according to an embodiment of the present invention, the organic-inorganic perovskite compound is an alkylenediammonium divalent cation in an amount of 0.02 to 0.06 moles based on 1 mole of the divalent metal ion. may contain.

In the organic-inorganic perovskite compound according to an embodiment of the present invention, based on 1 mole of the divalent metal ion, 0.90 to 0.99 moles of amidinium-based monovalent cations and 0.01 to 0.10 moles of alkylammonium-based compounds It may contain monovalent cations.

The present invention includes a method for preparing a film of the organic-inorganic perovskite compound described above.

The method for producing an organic-inorganic perovskite compound membrane according to the present invention contains an amidinium-based monovalent cation, an alkylammonium-based monovalent cation and an alkylenediammonium-based divalent cation as an organic cation, and an inorganic cation, Containing a divalent metal ion and an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion, applying and drying a perovskite solution containing a halogen ion as an inorganic anion; include

In the method for manufacturing an organic-inorganic perovskite compound membrane according to an embodiment of the present invention, the perovskite compound solution is 0.90 to 0.99 moles of amidinium-based monovalent cations based on 1 mole of divalent metal ions , containing 0.01 to 0.10 moles of an alkylammonium-based monovalent cation and 0.02 to 0.06 moles of an alkylenediammonium-based divalent cation, along with 0.05 to 0.25 moles based on 1 mole of the alkylenediammonium-based divalent cation of alkali metal ions.

The present invention includes a perovskite solar cell including a light absorption layer containing the above-described organic-inorganic perovskite compound.

The perovskite compound according to the present invention is improved photoelectric conversion efficiency and It has the advantage of having high light stability and excellent thermal and moisture stability.

Hereinafter, the organic-inorganic perovskite compound of the present invention will be described in detail. At this time, unless there are other definitions in the technical terms and scientific terms used, it has a meaning commonly understood by a person of ordinary skill in the art to which this invention belongs, and in the following description, it may unnecessarily obscure the subject matter of the present invention. A description of possible known functions and configurations will be omitted.

Also, the singular forms used in the specification and appended claims may also be intended to include the plural forms unless the context specifically dictates otherwise.

In this specification and the appended claims, terms such as first, second, etc. are used for the purpose of distinguishing one element from another, not in a limiting sense.

In this specification and the appended claims, terms such as include or have means that a feature or element described in the specification is present, and unless specifically limited, one or more other features or elements are added. This does not preclude the possibility that it will be.

In this specification and the appended claims, when a part of a film (layer), region, component, etc. is on or on another part, not only when it is directly on the other part in contact with it, but also another film ( layer), other regions, and other components are also included.

As a result of long-term research to improve the stability of amidinium-based perovskite compounds, the present applicants have used alkylenediammonium-based divalent cations and alkali metal cations satisfying a specific size as amidinium-based perovskite compounds. In the case of doping the compound, it was confirmed that, by the synergistic effect of co-doping, the thermal stability, moisture stability, and light stability of the amidinium-based perovskite compound were all significantly improved, and the photoelectric conversion efficiency was also significantly increased. Thus, the present invention was completed.

In the present invention, the perovskite compound, organic-inorganic perovskite compound, amidinium-based perovskite compound or amidinium-based organic-inorganic perovskite compound is an amidinium-based monovalent organic cation. It may mean an organometallic halide containing a cation and having a perovskite structure, and may mean an organometallic halide doped with an alkylenediammonium divalent cation and an alkali metal cation. At this time, the content of amidinium-based cations contained in the perovskite compound is 0.70 mol or more to less than 1.00 mol, 0.80 to 0.99 mol, 0.90 based on 1 mol of the divalent metal ion contained in the perovskite compound. to 0.99 moles or 0.95 to 0.99 moles.

The present invention includes one aspect based on the component contained in the perovskite compound and another aspect based on the dopant. may be applicable.

From the viewpoint of components of ions contained in the perovskite structure, the organic-inorganic perovskite compound according to an embodiment is an amidinium-based perovskite compound, an organic cation, an amidinium-based monovalent cation, an alkyl It contains an ammonium-based monovalent cation and an alkylenediammonium-based divalent cation, and contains, as an inorganic cation, an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion and the divalent metal ion, It contains a halogen ion as an inorganic anion.

From the viewpoint of the base material and the dopant doped to the base material, the organic-inorganic perovskite compound according to another embodiment is a dopant doped to the base material and the base material of the following Chemical Formula 1, and an organic dopant of an alkylenediammonium divalent cation and Chemical Formula 1 Including an inorganic dopant of alkali metal ions having an ionic radius of 0.8 to 1.3 based on the ionic radius of M.

(Formula 1)

A' _x A'' _1-x MX ₃

A' is a monovalent amidinium cation, A'' is a monovalent organic ammonium cation, M is a divalent metal ion, X is a halogen anion, and x is 0<x<1, 0.7≤x<1 , 0.8≤x<0.99, 0.90≤x<0.99, or 0.95≤x<0.99.

As described above, the perovskite compound according to the present invention contains an alkylenediammonium-based divalent cation and contains an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion, It may have improved photoelectric conversion efficiency, and may have excellent stability.

In one embodiment, the alkylenediammonium-based divalent cation may be a C1-C12 alkylenediammonium cation. The C1-C12 alkylenediammonium cation is advantageously a C1-C5 alkylenediammonium cation, more advantageously a C1-C3 alkylenediammonium cation, in terms of being homogeneously doped into the lattice structure of the perovskite compound. It may advantageously be a C1-C2 alkylenediammonium cation. The alkylenediammonium-based divalent cation may improve phase stability of the amidinium-based perovskite compound. However, when doped with a divalent alkylenediammonium-based cation alone, the light stability of the perovskite compound may be deteriorated. In the case of doping an alkali metal ion having an ionic radius, light stability can be remarkably improved by a synergistic effect by co-doping.

Alkali metal ions have an ionic radius of 0.8 to 1.3 (0.8R _M to 1.3R _M ) based on the ionic radius (R _M ) of the divalent metal ion (M of AMX ₃ ), specifically, an ionic radius of 0.9 to 1.2 (0.9R _M ) to 1.2R _M ), more specifically, may be an alkali metal ion having an ionic radius of 1 to 1.2 (1.0R _M to 1.2R _M ). Based on Pb ²⁺ , which is the most representative divalent metal ion of the perovskite compound, the alkali metal ion may include K ⁺ . Accordingly, when the divalent metal ion contains Pb ²⁺ , the alkali metal ion may contain K ⁺ .

Alkali metal ions satisfying the above-mentioned ionic radius are doped with alkylenediammonium divalent cations, and by the synergistic effect, the photoelectric conversion efficiency is improved by more than 109% compared to the undoped perovskite compound (base material). It can have a photoelectric conversion efficiency that is improved by 107% or more than the perovskite compound (base material) doped with alkali metal ions alone, and perovskite compounds doped with alkylenediammonium-based divalent cations alone ( It can have 103% or more improved photoelectric conversion efficiency compared to the base material). That is, alkali metal ions satisfying the above-described ionic radius and alkylenediammonium divalent cations are doped together to exhibit a synergistic effect, thereby increasing the photoelectric conversion efficiency by alkali metal ions alone and alkylenediammonium divalent cations. A significant improvement in the photoelectric conversion efficiency can be achieved beyond the sum of the increases in the photoelectric conversion efficiency alone.

In addition, due to the synergistic effect that appears when alkali metal ions satisfying the above-mentioned ionic radius and alkylenediammonium divalent cations are doped together, compared to alkali metal ion alone doping or alkylenediammonium divalent cation alone doping, it is significantly It can have improved light stability, and thermal and moisture stability, which is not improved by doping alone with alkali metal ions or doping with alkylenediammonium-based divalent cations alone, can also be remarkably improved by this co-doping.

In one embodiment, the perovskite compound may contain 0.02 to 0.06 moles, specifically 0.03 to 0.05 moles of an alkylenediammonium divalent cation based on 1 mole of the divalent metal ion. In other words, based on 1 mole of the base material according to Formula 1, 0.02 to 0.06 moles, specifically 0.03 to 0.05 moles of an alkylenediammonium-based divalent cation may be doped.

In one embodiment, the perovskite compound is 0.001 to 0.020 moles, specifically 0.002 to 0.02 moles, more specifically 0.0025 moles to 0.010 moles, even more specifically 0.003 to 0.008 moles, based on 1 mole of the divalent metal ion. It may contain alkali metal ions. In other words, based on 1 mole of the base material according to Formula 1, 0.001 to 0.020 moles, specifically 0.002 to 0.02 moles, more specifically 0.0025 moles to 0.010 moles, even more specifically 0.003 to 0.008 moles of alkali metal ions are doped can be

In one embodiment, the molar ratio of the alkylenediammonium-based divalent cation: the alkali metal ion contained in the perovskite compound (doped to the base material) is 1: 0.05 to 0.50, specifically 1: 0.10 to 0.30, more specifically to 1: 0.10 to 0.20.

The above-mentioned content ratio of alkali metal ions and alkylenediammonium cations is a synergistic effect of co-doping with potassium ions and alkylenediammonium cations, which cannot be obtained by doping alone with alkali metal ions or alkylenediammonium cations. This is the range in which photoelectric conversion efficiency, light stability, and heat and moisture stability can be improved.

In detail, when the perovskite compound contains an alkylenediammonium divalent cation and an alkali metal ion in the above content, even after 1 SUN and 1 hour of light soaking, the efficiency retention rate of 98% or more, It may have excellent light stability.

In addition, when the alkylenediammonium-based divalent cation and alkali metal ion are contained in the above-mentioned content, 96% or more of It can have good thermal and moisture stability, exhibiting efficiency retention.

In one embodiment, the alkylammonium-based monovalent cation is of the formula (R ₁ -NH ₃ ⁺ ) (R ₁ is C1-C24 alkyl) or (R ₂ -C ₃ H ₃ N ₂ ⁺ -R ₃ )(R ₂ may satisfy the formula of C1-C24 alkyl). As a non-limiting and specific example in consideration of the use of the light absorber, R ₁ may be C1-C7 alkyl, C1-C3 alkyl, or methyl. R ₂ may be C1-C24 alkyl and R ₃ may be hydrogen or C1-C24 alkyl, specifically R ₂ may be C1-C7 alkyl and R ₃ may be hydrogen or C1-C7 alkyl, More specifically, R ₂ may be methyl and R ₃ may be hydrogen. In one embodiment, the alkylammonium-based monovalent cation may be CH ₃ NH ₃ ⁺ .

In one embodiment, the amidinium-based monovalent cation may satisfy the following formula.

(Formula)

In this case, R ₄ to R ₈ are each independently hydrogen, C1-C24 alkyl, C3-C20 cycloalkyl, or C6-C20 aryl. In consideration of absorption of sunlight, as a non-limiting and specific example, R ₄ to R ₈ are each independently hydrogen, amino or C1-C24 alkyl, specifically hydrogen, amino or C1-C7 alkyl, more specifically hydrogen, may be amino or methyl. More specifically, R ₄ may be hydrogen, amino or methyl and R ₅ to R ₈ may be hydrogen. As a specific and non-limiting example, the amidinium-based monovalent cation is a formamidinium (formamidinium, NH ₂ CH=NH ₂ ⁺ ) ion, acetamidinium (acetamidinium, NH ₂ C(CH ₃ )=NH ₂ ⁺ ) or guamidinium (Guamidinium, NH ₂ C(NH ₂ )=NH ₂ ⁺ ) and the like.

In one embodiment, more than 0 moles to less than 1.00 moles, 0.70 moles or more to less than 1.00 moles, 0.80 to 0.99 moles, 0.90 to 0.99 moles or 0.95 to 0.95 moles based on 1 mole of the divalent metal ion contained in the perovskite compound. may contain 0.99 moles of amidinium-based monovalent cations, together with more than 0 moles to less than 1.00 moles, greater than 0 moles to 0.3 moles or less, 0.01 to 0.20 moles, 0.01 to 0.10 moles, or 0.01 to 0.05 moles. It may contain an alkylammonium-based monovalent cation.

In one embodiment, the molar ratio between the moles of the divalent metal ion contained in the perovskite compound: the molar ratio of the sum of the amidinium-based monovalent cation and the alkylammonium-based monovalent cation contained in the perovskite compound is 1: 0.8 to 1.3, specifically 1: 0.9 to 1.1 or 1: 0.95 to 1.05, substantially 1:1.

The inorganic anion (X) may include a halogen ion, and the halogen anion may be one or two or more selected from I ^- , Br ^- , F ^- and Cl ^- . As an example in consideration of the use of the light absorber, the halogen anion may include I ⁻ , and specifically include I ⁻ and Br ⁻ . When the inorganic anion contains I ^- and Br ^- , more than 0 moles to less than 1.00 moles, 0.70 moles or more to less than 1.00 moles, 0.80 to 0.99 moles, 0.90 to 0.99 moles, or 0.95 to 0.99 moles based on 1 mole of the total inorganic anions moles of I ⁻ , along with greater than 0 moles to less than 1.00 moles, greater than 0 moles to 0.3 moles or less, 0.01 to 0.20 moles, 0.01 to 0.10 moles or 0.01 to 0.05 moles of Br ^- have.

Examples of divalent metal ions (M) include Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Ge ²⁺ , Sn ²⁺ , One or two or more types selected from Pb ²⁺ and Yb ²⁺ may be mentioned, but the present disclosure is not limited thereto.

In one embodiment, the perovskite compound is an amidinium-based monovalent cation to A', an alkylammonium-based monovalent cation to A'', a divalent metal ion to M, an inorganic anion to X, A' _x A'' _1-x MX ₃ (x is a real number where 0<x<1, specifically, 0.7≤x<1, 0.8≤x<0.99, 0.90≤x<0.99 or 0.95≤x<0.99 Real number) is doped with an alkylenediammonium divalent cation of 0.02 to 0.06 moles, specifically 0.03 to 0.05 moles, per 1 mole of the base material, and the molar ratio of alkylenediammonium divalent cations: alkali metal ions It may be a compound doped with an alkali metal ion such that γ is 1:0.05 to 0.25, advantageously 1:0.10 to 0.20. In this case, the halogen anion of the base material may include I ^- , specifically I ^- and Br ^- . When the base material contains I ^- and Br ^- , I ^- as X' and Br ^- as X'', the base material is A' _x A'' _1-x M(X' _y X'' _1-y ) ₃ (x is a real number with 0<x<1, specifically, 0.7≤x<1, 0.8≤x<0.99, 0.90≤x<0.99, or 0.95≤x<0.99 real number, y is 0<y<1 is a real number, for example, 0.7≤y<1, 0.8≤y<0.99, 0.90≤y<0.99, or 0.95≤y<0.99) may be satisfied.

Accordingly, the present invention includes a method for preparing the above-described perovskite compound film.

As the above-described perovskite compound can be prepared by spontaneous crystallization (self-assembly) as the solvent is removed from a solution containing ions constituting the perovskite compound, conventional perovskite compound preparation The above-described perovskite compound film can be prepared using the solution application method used.

Specifically, the above-described perovskite compound film may be prepared by coating and drying a solution containing a base material ion source and a dopant source or containing a base material and a dopant source (hereinafter, a perovskite solution). That is, the perovskite solution may contain a base material or a base material ion source, a dopant source, and a solvent. The base material is the same as or similar to that described above for the perovskite compound. The parent material ion source may include a halide of a monovalent amidinium-based cation, a halide of a monovalent alkylammonium-based cation, and a halide of a divalent metal ion, and the dopant source is an alkylenediammonium-based cation. It may include a halide of a divalent cation and a halide of an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion. In this case, of course, the halogen anion, which is a counter anion of each cation, provides the inorganic anion of the perovskite compound.

The perovskite solution may contain a parent material ion source (or parent material) and a dopant source to satisfy the composition of the desired perovskite compound. In this case, the base ion source may contain a halide of a monovalent amidinium-based cation, a halide of a monovalent alkylammonium-based cation, and a halide of a divalent metal ion so as to satisfy the chemical formula of the above-described base material. .

Optionally, the perovskite solution further contains additives commonly used to improve the film quality of the prepared perovskite compound or to improve the interfacial properties between the perovskite compound and other components such as electron transporters. may contain. As an example of a typical additive, there may be mentioned methylammonium chloride, which is a chlorine source. Additives may be included at a level of 0.1 to 0.4 moles based on 1.00 moles of the base material, but it goes without saying that the present invention cannot be limited by the specific type and content of the additives. In addition, chlorine may be additionally supplied by using a relatively large amount of a halide of an alkylenediammonium-based divalent cation among dopant sources in the perovskite solution as a chloride.

The solvent of the perovskite solution may be any polar organic solvent in which the base ion source (or the base material) and the dopant source are easily dissolved and can be easily removed by volatilization during drying. For example, the solvent is gamma-butyrolactone, formamide, N,N-dimethylformamide, diformamide, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, diethylene glycol, 1-methyl-2- Pyrrolidone, N,N-dimethylacetamide, acetone, α-terpineol, β-terpineol, dihydroterpineol, 2-methoxyethanol, acetylacetone, methanol, ethanol, propanol, butanol, One or more may be selected from pentanol, hexanol, ketone, methyl isobutyl ketone, and the like, but the present invention is not limited by the specific material of the solvent.

The molar concentration of the base ion source (or base material) in the perovskite solution may be 0.5M to 1.4M, specifically 1.0M to 1.4M, but the present invention is not limited thereto.

Application of the perovskite solution includes inkjet printing, microcontact printing, imprinting, gravure printing, gravure-offset printing, flexography printing, offset/reverse offset printing, slot die coating, bar coating, blade coating, spray coating, It may be carried out by dip coating, roll coating, etc., but is not limited thereto.

After application of the solution, annealing the coating film may be further performed, and the annealing may be performed at a temperature of 80 to 200° C., specifically, 100 to 180° C., but is not limited thereto.

As described above, the perovskite compound film can be prepared using a solution application method of applying a perovskite solution, and further, a solvent-nonsolvent application in which the perovskite solution and a nonsolvent are sequentially applied. It can be prepared using a method. The solution application method and the solvent-nonsolvent application method may be performed with reference to Korean Patent No. 10-1547877 or No. 10-1547870 of the present applicant.

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

In one embodiment, the perovskite solar cell includes a first electrode, a first charge transporter positioned on the first electrode, a light absorption layer positioned on the first charge transporter and containing the above-described perovskite compound, the light It may include a second charge transfer member disposed on the absorption layer and transferring charges complementary to the first charge transport member, and a second electrode (counter electrode of the first electrode) disposed on the second charge transport member.

As a specific example in which the first charge carrier is an electron transport member and the second charge transport member is a hole transport member, the perovskite solar cell is positioned on the first electrode, the electron transport layer positioned on the first electrode, and the electron transport layer. a light absorption layer comprising a lobskite compound; an organic hole transport layer positioned on the light absorption layer; and a second electrode positioned on the organic hole transport layer.

In this case, at least one of the first electrode and the second electrode may be a transparent electrode, and both electrodes may be a transparent electrode, or one electrode may be a transparent electrode and the other electrode may be an opaque electrode (metal electrode).

The first electrode and the second electrode are not particularly limited as long as they are commonly used in perovskite solar cells. For example, when the first electrode (or the second electrode) is a transparent electrode, the electrode may be a transparent conductive electrode that is ohmically bonded to the electron transport layer. As a specific example, the transparent electrode may include fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), ZnO, carbon nanotube, graphene, and these It may be any one or two or more selected from the complex of. When the first electrode (or the second electrode) is an opaque electrode, the electrode is any one or two or more selected from gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and composites thereof. It may include a material, but is not limited thereto.

The electrode is to be formed through a deposition process such as physical vapor deposition or chemical vapor deposition on a transparent substrate (support) that is a rigid substrate (support) or flexible substrate (support). can As an example of the transparent substrate (support), the rigid substrate may be a glass substrate, and the flexible substrate is polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), polypropylene ( PP), triacetyl cellulose (TAC) or polyether sulfone (PES) may be used, but of course, the present invention is not limited to the specific material of the substrate.

The electron transport layer may be an inorganic material and may include a metal oxide. As a practical example, the electron transport layer may be a lamination film of a metal oxide film (dense film) and a porous (meso-porous) metal oxide film, more specifically, a lamination film of a dense film and a porous film.

The metal oxide film (dense film) may be formed through a deposition process such as physical vapor deposition or chemical vapor deposition, or coating and heat treatment of metal oxide nanoparticles.

The porous metal oxide film may include metal oxide particles, and may have a porous structure open by empty spaces between the particles.

In one example, the porous metal oxide film may be prepared by applying a slurry containing metal oxide particles on an upper portion of the metal oxide film (dense film), and drying and heat treating the applied slurry layer. The application of the slurry is performed by screen printing, spin coating, bar coating, gravure coating, blade coating, roll coating, etc. It may be performed by any one or two or more methods selected.

The main factors affecting the specific surface area and open pore structure of the porous metal oxide film are the average particle size of the metal oxide particles and the heat treatment temperature. The average particle size of the metal oxide particles may be 5 to 500 nm, and the heat treatment may be performed at 200 to 600° C. in air, but is not necessarily limited thereto.

The thickness of the electron transport layer may be, for example, 50 nm to 10 µm, specifically 50 nm to 5 µm, more specifically 50 nm to 1 µm, and even more specifically 50 to 800 nm, but must be It is not limited.

The metal oxide of the electron transport layer may be used without particular limitation as long as it is a metal oxide commonly used for photoelectron movement in solar cells, particularly perovskite solar cells. Specifically, for example, Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Zr oxide, Sr oxide, Yr oxide, La oxide, V oxide, Al oxide, Y oxide, It may be any one or two or more selected from Sc oxide, Sm oxide, Ga oxide, In oxide, SrTi oxide, and composites thereof.

The thickness of the light absorption layer is not particularly limited, but may be 100 nm to 1 μm, and specifically, 200 to 800 nm. The light absorption layer may be prepared through the above-described method for preparing the perovskite compound film.

The hole transport layer may be an organic hole transport layer, and the organic hole transport material of the organic hole transport layer may be a single molecule or a polymer organic hole transport material. Non-limiting examples of single to low molecular weight organic hole transport materials include pentacene, coumarin 6, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin), ZnPC (zinc phthalocyanine), CuPC (copper phthalocyanine), TiOPC (titanium oxide phthalocyanine), Spiro-MeOTAD(2,2',7,7'-tetrakis(N,N-p-dimethoxyphenylamino)-9,9'-spirobifluorene), F16CuPC(copper(II) 1 ,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine), SubPc (boron subphthalocyanine chloride) and N3 (cis -di(thiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II)) may include one or two or more materials selected from the group consisting of, but is not limited thereto.

As a non-limiting example of a polymer organic hole transport material, P3HT (poly[3-hexylthiophene]), MDMO-PPV (poly[2-methoxy-5-(3',7'-dimethyloctyloxyl)]-1,4-phenylene vinylene), MEH-PPV(poly[2-methoxy-5-(2''-ethylhexyloxy)-p-phenylene vinylene]), P3OT(poly(3-octyl thiophene)), POT( poly(octyl thiophene)), P3DT(poly(3-decyl thiophene)), P3DDT(poly(3-dodecyl thiophene), PPV(poly(p-phenylene vinylene)), TFB(poly(9,9'-dioctylfluorene-co-N-(4- butylphenyl)diphenyl amine), Polyaniline, Spiro-MeOTAD ([2,22′,7,77′-tetrkis (N,N-di-p-methoxyphenyl amine)-9,9,9′-spirobi fluorine]), PCPDTBT (Poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6- diyl]], Si-PCPDTBT(poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-( 2,1,3-benzothiadiazole)-4,7-diyl]), PBDTTPD(poly((4,8-diethylhexyloxyl) benzo([1,2-b:4,5-b']dithiophene)-2,6 -diyl)-alt-((5-octylthieno[3,4-c]pyrrole-4,6-dione)-1,3-diyl)), PFDTBT(poly[2,7-(9-(2-ethylhexyl) )-9-hexyl-fluorene)-alt-5,5-(4', 7, -di-2-thienyl-2',1' , 3'-benzothiadiazole)]), PFO-DBT (poly[2,7-.9,9-(dioctyl-fluorene)-alt-5,5-(4',7'-di-2-.thienyl-) 2', 1', 3'-benzothiadiazole)]), PSiFDTBT (poly[(2,7-dioctylsilafluorene)-2,7-diyl-alt-(4,7-bis(2-thienyl)-2,1, 3-benzothiadiazole)-5,5′-diyl]), PSBTBT(poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2 ,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), PCDTBT(Poly [[9-(1-octylnonyl)-9H-carbazole-2,7-diyl] -2 ,5-thiophenediyl -2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]), PFB(poly(9,9′-dioctylfluorene-co-bis(N,N′-(4, butylphenyl))bis(N,N′-phenyl-1,4-phenylene)diamine), F8BT(poly(9,9′-dioctylfluorene-co-benzothiadiazole), PEDOT (poly(3,4-ethylenedioxythiophene)), PEDOT : PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)), PTAA (poly(triarylamine)), Poly(4-butylphenyl-diphenyl-amine) and copolymers thereof However, the present invention is not limited thereto.

The hole transport layer is TBP (tertiary butyl pyridine), LiTFSI (Lithium Bis (Trifluoro methanesulfonyl) Imide), HTFSI (bis (trifluoromethane) sulfonimide), 2,6-lutidine and Tris (2- (1H -pyrazol-1-yl) Of course, it may further contain known additives such as pyridine) cobalt (III).

The thickness of the hole transport layer may be 10 to 500 nm, but is not necessarily limited thereto.

The hole transport layer may be formed by applying and drying a solution containing an organic hole transport material (hereinafter, referred to as an organic hole transport solution) on the light absorption layer. The solvent used to form the hole transport layer may be any solvent in which the organic hole transport material is dissolved and does not chemically react with the perovskite compound and the material of the electron transport layer. For example, the solvent used to form the hole transport layer may be a non-polar solvent, and as a practical example, toluene, chloroform, chlorobenzene, dichlorobenzene, anisole ( anisole), xylene, and may be any one or two or more selected from hydrocarbon-based solvents having 6 to 14 carbon atoms, but is not limited thereto.

The above-described second electrode may be positioned on the organic hole transport layer in contact with the organic hole transport layer.

Hereinafter, the excellence of the perovskite compound according to the present invention is experimentally demonstrated based on the perovskite solar cell, which is the most representative use of the perovskite compound, but the present invention may be limited by the examples presented. Of course none.

(Example 1)

A 20 mM solution of titanium diisopropoxide bis (acetylacetonate) on an FTO substrate (a glass substrate coated with fluorine-containing tin oxide, FTO; F-doped SnO ₂ , 8 ohms/cm ² , Pilkington) at 450° C. A 60 nm TiO ₂ thin film was prepared by spray pyrolysis.

Thereafter, anatase-phase TiO ₂ nanoparticle paste (SC-HT040, ShareChem, Korea) with an average diameter of 50 nm was spin-coated on the TiO ₂ thin film and calcined in air at 500° C. for 1 hour to form a 100 nm-thick porous TiO ₂ layer. formed.

NN-dimethylformamide (DMF): 0.8 g of FAPbI ₃ (FA = formamidinium), 0.01 g of MAPbBr ( MA=methylammonium), 0.03 g of additive (methylammonium chloride), and a dopant source were mixed to prepare a perovskite solution. The composition of the base material was (FAPbI ₃ ) _0.983 (MAPbBr ₃ ) _0.017 , and as a dopant source, methylene diammonium dihydrochloride and potassium iodide were added to satisfy 0.04 moles compared to 1 mole of the base material and 0.0050 moles compared to 1 mole of the base material. .

Thereafter, the perovskite solution prepared on the porous TiO ₂ layer was spin-coated at 1000 rpm for 5 sec and 5000 rpm for 20 sec. During the spin coating of the perovskite solution, after 12 seconds from the start of the coating, 1 ml of diethyl ether was injected and , and annealing at 150° C. for 10 minutes after spin coating was completed to form a perovskite compound film (light absorption layer) doped with divalent methylenediammonium cations and potassium cations.

Then, the organic hole transport solution was spin-coated on the prepared light absorption layer at 2000 rpm for 30 seconds to form an organic hole transport layer. At this time, the organic hole transport solution was prepared by dissolving Spiro-OMeTAD in chlorobenzene to have a concentration of 30 mg/ml, and 21.5 μl Li-bis(trifluoromethanesulfonyl) imide (Li-TFSI)/acetonitrile (170 mg/ml) as an additive. 1ml), 21.5 μl TBP (4-tert-Butylpyridine was added).

Then, Au was vacuum-deposited with a high vacuum (5x10 ^-6 torr or less) thermal evaporator to form an Au electrode (second electrode) having a thickness of about 60 nm.

(Examples 2-4)

When preparing the perovskite solution in Example 1, instead of 0.0050 mol of potassium iodide relative to 1 mol of the base material, 0.0020 mol (Example 2), 0.0025 mol (Example 3) or 0.0100 mol (Example 4) of potassium A solar cell was manufactured in the same manner as in Example 1, except that iodide was added.

(Comparative Example 1)

A solar cell was prepared in the same manner as in Example 1, except that a dopant source was not added when preparing the perovskite solution in Example 1.

(Comparative Example 2)

A solar cell was manufactured in the same manner as in Example 1, except that, when preparing the perovskite solution in Example 1, only potassium iodide was added as a dopant source without adding methylenediammonium dihydrochloride.

(Comparative Examples 3-5)

When preparing the perovskite solution in Example 1, only methylenediammonium dihydrochloride was added as a dopant source without adding potassium iodide, but 0.02 mol (Comparative Example 3), 0.04 mol (Comparative Example) compared to 1 mol of the base material 4) or 0.06 mol (Comparative Example 5), except that the input was prepared in the same manner as in Example 1 to prepare a solar cell.

The characteristics of the manufactured solar cells were measured using a Keithley 2420 source meter and a solar simulator (Newport Oriel Class A 91195A) using a 450 W Xe-lamp (Oriel) with an AM 1.5 G filter, using a standard 100 mW/cm ² (1 SUN) conditions. Current density versus voltage (JV) was measured in the range of 1.5V to -0.2V with a step of 10mV and a scan rate of 150mV/sec. Table 1 summarizes the short-circuit current density (J _SC ), open circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (PCE) of the solar cells manufactured in Examples to Comparative Examples.

(Table 1)

The solar cell of Comparative Example 1 was a solar cell (hereinafter referred to as a reference solar cell) provided with a light absorption layer made of only a base material, and exhibited a photoelectric conversion efficiency of 22.85%. Comparative Example 2 doped with only the same amount of alkali ion (potassium ion) as in Example 1, Comparative Examples 3, 4 and 5 doped with an alkylenediammonium divalent cation of 0.02 mol, 0.04 mol or 0.06 mol relative to 1 mol of the base material All of them have higher photoelectric conversion efficiency than the reference solar cell, and it can be seen that both alkali ions and divalent alkylenediammonium-based cations improve the photoelectric properties of the solar cell. However, looking at the photoelectric conversion efficiency of the solar cells manufactured in Examples 1 to 4, even if both the degree of improvement by the alkali ion doping and the degree of improvement by the alkylenediammonium-based cation doping are considered, alkali ions and alkylene It can be seen that the photoelectric conversion efficiency is significantly improved by the synergistic effect of co-doping of diammonium-based cations. In particular, the photoelectric conversion efficiency of 25.07% of the solar cell prepared in Example 1 is the highest among the efficiencies of the perovskite solar cell reported so far.

The solar cell light stability test was performed by maximum power point tracking (MPPT) for 1 hour under the condition of 100 mW/cm ² (1 SUN). During the test, the ambient temperature and humidity were maintained at 25°C and 30% relative humidity.

Table 2 shows the efficiency before the light stability test (initial efficiency), the efficiency (light soaking efficiency) and the efficiency maintenance rate (%) after the light stability test (light immersion) of the solar cells manufactured in Examples to Comparative Examples.

(Table 2)

As can be seen from the results of Comparative Examples 1 to 5 in Table 2, it can be seen that although the photostability is improved by the alkali metal ion doping, the photostability is rather greatly reduced when the alkylenediammonium-based cation is doped.

However, as in the embodiment, when an alkali metal ion and an alkylenediammonium-based cation are co-doped, the light stability is significantly higher than that of the alkali metal ion alone doping due to the synergistic effect of the alkali metal ion and the alkylenediammonium-based cation. improvement can be seen. In particular, in the case of Example 1, it can be confirmed that the efficiency maintenance ratio of 98% or more is substantially not caused by light deterioration.

The thermal and moisture stability test was conducted under a very harsh environment in which heat and moisture were simultaneously applied. In detail, the thermal and moisture stability test was performed by leaving the prepared perovskite solar cell in a thermo-hygrostat maintained at 85° C. and a relative humidity of 85% for 100 hours. Table 3 shows the efficiency (initial efficiency) before the thermal and moisture stability test, the efficiency (8585 efficiency) and the efficiency maintenance rate (%) after the thermal and moisture stability test of the manufactured solar cell. In the thermal and moisture stability test, there is a risk that the hole transport layer influences the overall moisture and thermal stability of the solar cell due to the moisture vulnerability of Spiro-OMeTAD. Accordingly, in the thermal and moisture stability test, a solar cell in which a hole transport layer of poly(triarylamine) (PTAA) was formed instead of a hole transport layer of Spiro-OMeTAD in Comparative Examples 1, 2, and 4 and Example 1 was used. In detail, the PTAA hole transport layer is formed on the prepared perovskite compound film, PTAA is added to toluene so that 11 mg/ml, and 3.7 μl of Li-TFSI (Li-bis (trifluoromethanesulfonyl) imide) acetonitrile solution ( 340 mg/ml) and 3.7 μl of t BP (4-tert-butylpyridine) were mixed to form a hole transport solution prepared by spin coating at 3000 rpm for 30 seconds.

(Table 3)

As can be seen from Table 3, in the case of the reference solar cell (Comparative Example 1), the efficiency retention rate was 95.31%, and the efficiency retention ratio of the solar cell of Comparative Example 2 doped with only the same amount of alkali metal ions as in Example 1 was 95.35%. , it can be seen that only alkali metal ion doping under severe conditions hardly improves thermal and moisture stability. In addition, in the case of the solar cell of Comparative Example 4 doped with only the same amount of alkylenediammonium-based cations as in Example 1, the efficiency retention rate was 89.49%, indicating that thermal and moisture stability was rather deteriorated. However, when the alkali metal ion and the alkylenediammonium-based cation are co-doped, the efficiency maintenance rate is 96.54% due to the synergistic effect of the alkali metal ion and the alkylenediammonium-based cation, and it can be seen that the thermal and moisture stability is greatly improved. have.

As described above, the present invention has been described with specific details and limited examples and drawings, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is not limited to the above embodiments. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims described below, but also all of the claims and all equivalents or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (10)

As an organic cation, it contains an amidinium-based monovalent cation, an alkylammonium-based monovalent cation and an alkylenediammonium-based divalent cation,
As an inorganic cation, it contains a divalent metal ion and an alkali metal ion having an ionic radius of 0.8 to 1.3 based on the ionic radius of the divalent metal ion,
Organic/inorganic perovskite compounds containing halogen ions as inorganic anions. The method of claim 1,
The alkali metal ion is an organic-inorganic perovskite compound comprising K ⁺ . 3. The method of claim 2,
The organic-inorganic perovskite compound wherein the alkylenediammonium-based divalent cation is a C1-C12 alkylenediammonium cation. The method of claim 1,
The organic-inorganic perovskite compound is an organic-inorganic perovskite compound containing 0.001 to 0.020 moles of alkali metal ions based on 1 mole of the divalent metal ions. 3. The method of claim 2,
The organic-inorganic perovskite compound is an organic-inorganic perovskite compound containing 0.02 to 0.06 moles of alkylenediammonium-based divalent cations based on 1 mole of the divalent metal ion. The method of claim 1,
An organic-inorganic perovskite compound containing 0.90 to 0.99 moles of an amidinium-based monovalent cation and 0.01 to 0.10 moles of an alkylammonium-based monovalent cation based on 1 mole of the divalent metal ion. The base material of Formula 1 and the dopant doped into the base material, including an organic dopant of an alkylenediammonium-based divalent cation and an inorganic dopant of alkali metal ions having an ionic radius of 0.8 to 1.3 based on the ionic radius of M in Formula 1 organic-inorganic perovskite compound.
(Formula 1)
A' _x A'' _1-x MX ₃
(A' is a monovalent amidinium cation, A'' is a monovalent organic ammonium cation, M is a divalent metal ion, X is a halogen anion, and x is a real number where 0<x<1) As an organic cation, it contains an amidinium-based monovalent cation, an alkylammonium-based monovalent cation and an alkylenediammonium-based divalent cation, and as an inorganic cation, a divalent metal ion and 0.8 based on the ionic radius of the divalent metal ion to containing an alkali metal ion having an ionic radius of 1.3, and applying and drying a perovskite solution containing a halogen ion as an inorganic anion; A method for preparing a film of an organic-inorganic perovskite compound according to the present invention. 9. The method of claim 8,
The perovskite compound solution contains 0.90 to 0.99 moles of amidinium-based monovalent cations, 0.01 to 0.10 moles of alkylammonium-based monovalent cations, and 0.02 to 0.06 moles of alkylenediammonium based on 1 mole of divalent metal ions. A method containing a divalent cation, and, together with it, an alkali metal ion of 0.05 to 0.25 moles based on 1 mole of the alkylenediammonium divalent cation. A perovskite solar cell comprising a light absorption layer containing the organic-inorganic perovskite compound according to any one of claims 1 to 7.