WO2022039522A1 - Perovskite thin film having passivated crystalline grain boundary, method for preparing same, and electronic device comprising same - Google Patents

Abstract

The present invention relates to a perovskite thin film having passivated crystalline grain boundary, a method for preparing same, and a perovskite thin film comprising same, the perovskite thin film comprising: perovskite structure crystalline; and Lewis base crystalline formed on the grain boundary of the perovskite structure crystalline. An electronic device employing the perovskite thin film of the present invention has surprisingly enhanced properties.

Description

Perovskite thin film having passivated grain boundaries, manufacturing method thereof, and electronic device comprising same

The present invention relates to a method for manufacturing a perovskite thin film having passivated grain boundaries and an electronic device including the same.

In order to manufacture a high-efficiency perovskite solar cell, it is essential to produce a perovskite thin film with a uniform thickness and excellent crystallinity and a large crystal size. In order to manufacture a high-efficiency solar cell, it is required to improve the uniformity and quality of the perovskite thin film to produce a perovskite thin film with high density and excellent crystallinity. However, in the prepared perovskite thin film, grain boundaries between crystals are inevitably formed due to the characteristics of the manufacturing method, and as a result, it is difficult to form a uniform thin film due to the grain boundaries.

It is difficult to make a thin film with excellent electrochemical properties while making a uniform thin film, so it is difficult to implement only with a pure perovskite solution. Although a method for producing a was known, there was a limit to producing a uniform perovskite thin film.

In order to solve the above problems, the present invention provides a passivation ( passivation) and confirmed that the efficiency of an electronic device including the same can be improved, and the present invention has been completed.

Accordingly, the present invention provides a perovskite thin film having a passivated grain boundary and a method for manufacturing the same.

In addition, the present invention provides an electronic device using the perovskite thin film of the present invention.

In order to achieve the above object, the present invention provides a perovskite thin film having a passivated grain boundary, the perovskite thin film of the present invention,

perovskite structure determination; and

and a Lewis base crystal formed at the grain boundary of the perovskite structure crystal.

The Lewis base according to an embodiment of the present invention may be a compound including any one or two or more electron donor elements selected from N, O, and S, and preferably a pKa value of 8 or more.

Specifically, the Lewis base according to an embodiment of the present invention is piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, 1-methylpyrrolidine, diethylamine , triethylamine, tetramethylethylenediamine, and methyl-4-pyridinemethylamine may be any one or two or more selected from, but is not limited thereto.

The perovskite thin film according to an embodiment of the present invention may be formed by heat-treating a perovskite precursor solution containing a compound satisfying the following Chemical Formula 1 and a metal halide satisfying the following Chemical Formula 2.

[Formula 1]

AX

[Formula 2]

mx ₂

(In Formulas 1 and 2,

A is Cs ⁺ or an organocation;

M is selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof;

X is Br ^- , Cl ^- or I ^- .)

Specifically, the organocation of A in Formula 1 according to an embodiment of the present invention may be a compound represented by Formula 3 or Formula 4 below.

[Formula 3]

(R ¹ R ² N=CH-NR ³ R ⁴ ) ⁺

[Formula 4]

(R ⁵ R ⁶ R ⁷ R ⁸ N) ⁺

(In Formulas 3 and 4,

R ¹ to R ⁴ are each independently selected from hydrogen and unsubstituted or substituted (C1-C6)alkyl;

R ⁵ to R ⁸ are each independently selected from hydrogen and unsubstituted or substituted (C1-C20)alkyl or unsubstituted or substituted aryl.)

In addition, the present invention provides a method for manufacturing a perovskite thin film having an immobilized grain boundary of the present invention, the method for manufacturing a perovskite thin film of the present invention is

forming a perovskite structure crystal by applying a perovskite solution to a substrate and performing primary heat treatment; and

and applying a Lewis base solution to the perovskite structure crystal and performing secondary heat treatment to form a Lewis base crystal at the grain boundary of the perovskite structure crystal.

The Lewis base solution according to an embodiment of the present invention may have a pKa value of 8 or more, specifically piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, and 1 -Methylpyrrolidine, diethylamine, triethylamine, tetramethylethylenediamine, and may be any one or two or more selected from methyl-4-pyridinemethylamine, but is not limited thereto.

The primary heat treatment according to an embodiment of the present invention may be performed at a temperature of 50 to 300 °C, and the secondary heat treatment may be performed at a temperature of 50 to 150 °C.

In addition, the present invention provides an electronic device comprising the perovskite thin film of the present invention.

The perovskite thin film according to an embodiment of the present invention effectively inhibits the oxidation of metal cations in the perovskite structure by placing Lewis base crystals at the grain boundaries of the perovskite structure crystals, thereby forming the perovskite structure. By making it stable, the efficiency of the electronic device including the same is improved.

The method of manufacturing a perovskite thin film according to an embodiment of the present invention is different from the conventionally known method of adding a Lewis base compound to a perovskite precursor solution, after forming a perovskite structure crystal By applying and heat-treating the Lewis base formed on the rovskite structure crystal, the Lewis base is not only evenly distributed at the perovskite grain boundary, but also stably maintained on the perovskite thin film at high temperature, thereby maintaining the perovskite thin film grain boundary. can maintain the immobilization of

Therefore, the electronic device including the perovskite thin film of the present invention has surprisingly improved properties.

1 is a photograph (b) of a thin film after spin-coating DMAP on a crystal (a), a substrate prepared in Preparation Example 1, and heating it at 100° C. for 30 minutes, and a perovskite thin film prepared in Example 1 SEM image of (c) is shown.

Figure 2 shows the time-dependent SEM image of the perovskite thin film of Example 1 of the present invention.

FIG. 3 shows SEM images of non-annealing and annealing when 4-dimethylaminopyridine is applied.

4 shows the XRD diffraction patterns of DMAP, the perovskite thin film and the perovskite thin film prepared in Example 1.

FIG. 5 shows SEM images for each concentration of 4-dimethylaminopyridine of the perovskite thin film.

Figure 6 shows the X-ray diffraction pattern for each concentration of 4-dimethylaminopyridine of the perovskite thin film.

7 is a graph showing the change of TCSPC (Time-Correlated Single Photon Counting) using the perovskite thin film prepared in Examples 2 to 5 of the present invention.

8 is a graph showing the strength of adhesion between the perovskite thin film and the hole transport layer prepared in Example 1 and Comparative Example 1 of the present invention.

9 is a graph showing the long-term stability of the perovskite solar cells prepared in Example 1 and Comparative Example 1 of the present invention.

10 is a view confirming 4-dimethylaminopyridine (DMAP) crystals on the perovskite thin film of the present invention through GIWAX measurement.

Hereinafter, a perovskite thin film having an immobilized grain boundary according to the present invention and a method for manufacturing the same will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms. Also, like reference numerals refer to like elements throughout.

At this time, if there is no other definition in the technical terms and scientific terms used, it has the meaning commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may be unnecessarily obscure will be omitted.

As used herein, the term “alkyl” refers to a saturated straight-chain or branched non- having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms (when the number of carbon atoms is not particularly limited). It means a cyclic hydrocarbon. "Lower alkyl" means straight-chain or branched alkyl having 1 to 4 carbon atoms. Representative saturated straight chain alkyls are -methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, -n-hexyl, -n-heptyl, -n-octyl, -n-nonyl and -n- contains decyl, whereas saturated branched alkyl is -isopropyl, -sec-butyl, -isobutyl, -tert-butyl, isopentyl, 2-methylhexyl, 3-methylbutyl, 2-methylpentyl, 3- Methylpentyl, 4-methylpentyl, 2-methylhexyl, 3-methylhexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5- Methylhexyl, 2,3-dimethylbutyl, 2,3-dimethylpentyl, 2,4-dimethylpentyl, 2,3-dimethylhexyl, 2,4-dimethylhexyl, 2,5-dimethylhexyl, 2,2-dimethyl Pentyl, 2,2-dimethylhexyl, 3,3-dimethylpentyl, 3,3-dimethylhexyl, 4,4-dimethylhexyl, 2-ethylpentyl, 3-ethylpentyl, 2-ethylhexyl, 3-ethylhexyl, 4-ethylhexyl, 2-methyl-2-ethylpentyl, 2-methyl-3-ethylpentyl, 2-methyl-4-ethylpentyl, 2-methyl-2-ethylhexyl, 2-methyl-3-ethylhexyl, 2-methyl-4-ethylhexyl, 2,2-diethylpentyl, 3,3-diethylhexyl, 2,2-diethylhexyl, and 3,3-diethylhexyl.

When described as "C1-6" in the present specification, it means that it has 1 to 6 carbon atoms. For example, C 1-6 alkyl means alkyl having 1 to 6 carbon atoms.

As used herein, “heterocycle” is a cyclic compound containing a heteroatom, including heterocycloalkyl and heteroaryl, and may be a C3-C20, preferably C3-C12, more preferably C3-C8 heterocyclic compound. there is.

As used herein, the term “heterocycloalkyl” has 2 to 12, preferably 2 to 10 carbon atoms and 1 to 6 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur, for example 1 to 5 refers to a stable 3- to 18-membered saturated or partially unsaturated radical consisting of heteroatoms, 1 to 4 heteroatoms, 1 to 3 heteroatoms, or 1 to 2 heteroatoms. Exemplary heterocyclealkyls include, but are not limited to, stable 3-15 membered saturated or partially unsaturated radicals, stable 3-12 membered saturated or partially unsaturated radicals, stable 3-9 membered saturated or partially unsaturated radicals, stable 8-membered saturated or partially unsaturated radicals, and stable 8-membered saturated or partially unsaturated radicals. radicals, stable 7-membered saturated or partially unsaturated radicals, stable 6-membered saturated or partially unsaturated radicals, or stable 5-membered saturated or partially unsaturated radicals.

As used herein, "heteroaryl" has at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur, and includes 5 to 10 carbon atoms including at least one carbon atom, including mono- and bicyclic ring systems. It is an aromatic heterocycle ring of members. Representative heteroaryls include triazolyl, tetrazolyl, oxadiazolyl, pyridyl, furyl, benzofuranyl, thiophenyl, benzothiophenyl, quinolinyl, pyrrolyl, indolyl, oxazolyl, benzoxazolyl ( benzoxazolyl), imidazolyl, benzimidazolyl, thiazolyl, benzothiazolyl, isoxazolyl, pyrazolyl, isothiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, tria Zinyl, cinnolinyl, phthalazinyl, quinazolinyl, pyrimidyl, oxetanyl, azepinyl, piperazinyl, morpholinyl, dioxanyl, thietanyl and oxazolyl. A heteroaryl group may be monocyclic or bicyclic. Heteroaryl may be used interchangeably with the terms heteroaryl ring, heteroaryl group, or heteroaromatic, and all of these terms may include an optionally substituted ring.

As used herein, the term "substituted" means that the hydrogen atom of the moiety being substituted (eg, alkyl, aryl, heteroaryl, heterocycle, or cycloalkyl) is replaced by a substituent. In one embodiment, each carbon atom of the group being substituted is unsubstituted by more than two substituents. In another embodiment, each carbon atom of the group being substituted is unsubstituted by more than one substituent. In the case of a keto substituent, the two hydrogen atoms are replaced by an oxygen attached to the carbon by a double bond. Unless otherwise stated with respect to the substituent, optionally substituted substituents of the present invention include halogen, hydroxyl, (lower) alkyl, haloalkyl, mono- or di-alkylamino, aryl, heterocycle, -NO ₂ , -NR _a1 R _b1 , -NR _a1 C(=O) R _b1 , -NR _a1 C(=O)NR _a1 R _b1 , -NR _a1 C(=O)OR _b1 , -NR _a1 SO ₂ R _b1 , - OR _a1 , -CN, -C(=O)R _a1 , -C(=O)OR _a1 , -C(=O)NR _a1 R _b1 , -OC(=O)R _a1 , -OC(=O) OR _a1 , -OC(=O)NR _a1 R _b1 , -NR _a1 SO ₂ R _b1 , -PO ₃ R _a1 , -PO(OR _a1 )(OR _b1 ), -SO ₂ R _a1 , -S(O) R _a1 , -SO(NR _a1 )R _b1 (eg sulfoximine), -S(NR _a1 )R _b1 (eg sulfilimine) and -SR _a1 may be used, wherein R _a1 and R _b1 may be the same or different, independently of each other hydrogen, halogen, amino, alkyl, _alkoxyalkyl , haloalkyl, aryl or heterocycle _; can Here, R _a1 and R _b1 may be plural depending on the atom to which they are bonded, and preferably, the alkyl may be C _1-6 alkyl, aryl may be C _6-12 , and heterocycle may be C _3-12 . there is. Preferably “substituted” substituents are hydrogen, halogen, amino, (C1-C10)alkyl, (C1-C10)alkoxy(C1-C10)alkyl, halo(C1-C10)alkyl, (C6-C12)aryl, (C3-C10)heterocycle or (C3-C12)heteroaryl.

One aspect of the present invention is a perovskite thin film having a passivated grain boundary.

Perovskite thin film according to an embodiment of the present invention is a perovskite structure crystal; and

and a Lewis base crystal formed at the grain boundary of the perovskite structure crystal.

In the perovskite thin film according to an embodiment of the present invention, the presence of a Lewis base at the grain boundary of the perovskite structure crystal can be found through GIWAX measurement of the perovskite thin film.

Specifically, in the perovskite thin film according to an embodiment of the present invention, a Lewis base is selectively present at the grain boundary of the perovskite structure crystal, thereby preventing defects in the perovskite structure crystal. Therefore, the perovskite thin film of the present invention has excellent properties.

That is, the Lewis base present at the grain boundary of the perovskite thin film according to an embodiment of the present invention is selectively distributed at the grain boundary interface of the perovskite thin film unlike conventional surface treatment materials, and the formed Lewis base crystal is The passivation is stably maintained even at a high temperature, specifically 100 ℃, which greatly improves the efficiency of the electronic device employing it.

More specifically, as can be seen from the GIWAX measurement results as shown in FIG. 10, the perovskite thin film according to an embodiment of the present invention has a crystal of a Lewis base at the grain boundary of the perovskite structure crystal. Able to know.

As a result, it can be seen that the electronic device including the perovskite thin film of the present invention has more improved efficiency and durability.

The Lewis base according to an embodiment of the present invention may be a compound containing any one or two or more electron donor elements selected from N, O, and S, and specifically, any one or two or more selected from N, O and S It may be a C3-C20 heterocyclic compound containing an electron donor element.

The Lewis base according to an embodiment of the present invention may be a monomolecular C3-C20 heterocyclic compound containing any one or two or more electron donor elements selected from N, O, and S, and is preferably selected from N and O. It may be monomolecular C3-C10 heterocycloalkyl or monomolecular C3-C10 heteroaryl containing at least one.

Preferably, the Lewis base according to an embodiment of the present invention may be a mono-molecular C3-C10 heterocycloalkyl or a mono-molecular C3-C10 heteroaryl into which a mono-C1-C10 alkylamino group or a di-C1-C10 alkylamino group is introduced.

More preferably, the Lewis base according to an embodiment of the present invention may be a compound represented by the following Chemical Formula 5 or Chemical Formula 6.

[Formula 5]

[Formula 6]

(In Formulas 5 and 6,

R and R' are independently of each other C1-C5 alkyl;

A is O, S or NR ₂₄ ;

R ₁₁ , R ₁₂ and R ₂₁ to R ₂₄ are each independently hydrogen or C 1 -C 5 alkyl;

n is an integer from 0 to 4, and m is an integer from 0 to 3.)

Preferably, in Formulas 5 and 6, R and R' are each independently C1-C3 alkyl; A is O, S or NR ₂₄ ; R ₁₁ , R ₁₂ , R ₂₁ to R ₂₄ are each independently hydrogen or C 1 -C 3 alkyl; n is an integer from 0 to 2, m may be an integer from 0 to 2, R and R' are each independently C1-C3 alkyl; A is O or NR ₂₄ ; R ₁₁ , R ₁₂ , R ₂₁ to R ₂₄ are each independently hydrogen or C 1 -C 3 alkyl; n may be an integer from 0 to 1, and m may be an integer from 0 to 1.

Specifically, the Lewis base is piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, 1-methylpyrrolidine, diethylamine, triethylamine, tetramethylethylene. It may be any one or two or more selected from diamine and methyl-4-pyridinemethylamine, and preferably, the Lewis base according to an embodiment of the present invention may have a pKa value of 8 or more.

The perovskite structure crystal according to an embodiment of the present invention may be formed by heat-treating a perovskite precursor solution containing a compound satisfying the following Chemical Formula 1 and a metal halide satisfying the following Chemical Formula 2.

[Formula 1]

AX

[Formula 2]

mx ₂

In Formulas 1 and 2,

A is Cs ⁺ or an organocation;

M is selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof;

X is Br ^- , Cl ^- or I ^- .

The organic cation of A in Formula 1 according to an embodiment of the present invention may be a compound represented by Formula 3 or Formula 4 below.

[Formula 3]

(R ¹ R ² N=CH-NR ³ R ⁴ ) ⁺

[Formula 4]

(R ⁵ R ⁶ R ⁷ R ⁸ N) ⁺

(In Formulas 3 and 4,

R ¹ to R ⁴ are each independently selected from hydrogen and unsubstituted or substituted (C1-C6)alkyl;

R ⁵ to R ⁸ are each independently selected from hydrogen and unsubstituted or substituted (C1-C20)alkyl or unsubstituted or substituted aryl.)

The Lewis base employed in the present invention is characterized in that it is a compound containing any one or two or more electron donor elements selected from N, O and S. In addition, the Lewis base employed in the present invention is characterized in that the pKa value (which is the pKa value in water) is 8 or more, specifically, the pKa value is 9 or more and 13 or less. If the pKa value is less than 8, the passivation effect of the perovskite grain boundaries may be reduced.

In one embodiment, the Lewis base is piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, 1-methylpyrrolidine, diethylamine, triethylamine , may be any one or two or more selected from tetramethylethylenediamine and methyl-4-pyridinemethylamine, but is not limited thereto.

More preferably, the Lewis base may be any one or two or more selected from 4-dimethylaminopyridine, 1-methylpiperidine and tetramethylethylenediamine. Among the Lewis bases according to an embodiment of the present invention, the compounds represented by Chemical Formulas 5 and 6 are uniformly dispersed in the perovskite grain boundaries and then bound, thereby effectively passivating the perovskite grain boundaries. there is.

The perovskite thin film of the present invention is characterized in that a hole transport layer is formed on the perovskite thin film in which Lewis base crystals are formed at grain boundaries.

Hereinafter, a method for manufacturing a perovskite thin film having a passivated grain boundary according to the present invention will be described in detail.

The manufacturing method of the perovskite thin film of the present invention,

forming a perovskite structure crystal by applying a perovskite precursor solution to a substrate and performing primary heat treatment; and

forming a Lewis base crystal at the grain boundary of the perovskite structure by applying a Lewis base solution to the crystals of the perovskite structure and performing secondary heat treatment;

includes

In the manufacturing method according to the present invention, the first step is a step of forming a perovskite structure crystal by applying a perovskite precursor solution to a substrate and performing primary heat treatment.

At this time, in order to perform the above step, a perovskite precursor solution containing an inorganic or organic halide or a metal halide is applied on a substrate and subjected to a primary heat treatment.

The inorganic or organic halide according to an embodiment of the present invention may satisfy the following formula (1).

[Formula 1]

AX

(In Formula 1,

A is Cs ⁺ or an organocation;

X is Br ^- , Cl ^- or I ^- .)

The metal halide according to an embodiment of the present invention may satisfy the following formula (2).

[Formula 2]

mx ₂

(In Formula 2,

M comprises a metal selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof;

X is Br ^- , Cl ^- or I ^- .)

According to an embodiment, the organic cation of A in Formula 1 may be represented by Formula 3 or Formula 4 below.

[Formula 3]

(R ¹ R ² N=CH-NR ³ R ⁴ ) ⁺

[Formula 4]

(R ⁵ R ⁶ R ⁷ R ⁸ N) ⁺

(In Formulas 3 and 4,

R ¹ to R ⁴ are each independently selected from hydrogen and unsubstituted or substituted (C1-C6)alkyl;

R ⁵ to R ⁸ are each independently selected from hydrogen and unsubstituted or substituted (C1-C20)alkyl or unsubstituted or substituted aryl.)

More specifically, Chemical Formula 1 may be selected from CH ₃ NH ₃ I (methylammonium iodide), CH(NH ₂ ) ₂ I (formamidinium iodide), or CsI (cesium iodide).

In an example of the present invention, the perovskite precursor solution may contain 0.8 to 1.2 moles of a metal halide with respect to 1 mole of the inorganic or organic halide.

The first heat treatment for annealing the applied perovskite precursor solution is not particularly limited as long as the solution is sufficiently dried and the temperature at which the perovskite structure can be stably maintained, but in one embodiment, the heat treatment is 50 to It may be carried out at a temperature of 300 °C for 10 minutes to 4 hours.

Before forming the perovskite structure crystal, the step of forming a metal oxide thin film may be further performed, and the forming step of the metal oxide thin film may be performed by chemical or physical vapor deposition used in a typical semiconductor process, and , The material of the metal oxide thin film is, 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, It may be at least one material selected from Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, SrTi oxide, and composites thereof, and more preferably, at least one material selected from Ti oxide, Sn oxide, and composites thereof. there is.

In the manufacturing method according to the present invention, the second step is a step of forming a Lewis base crystal at the grain boundary of the perovskite structure by applying a Lewis base solution to the crystals of the perovskite structure and performing secondary heat treatment.

The Lewis base employed in the present invention may be any one selected from N, O, and S, or a compound containing two or more electron donor elements. In addition, the Lewis base employed in the present invention is characterized in that the pKa value is 8 or more, specifically, the pKa value is 9 or more and 13 or less. If the pKa value is less than 8, the passivation effect of the perovskite grain boundaries may be reduced.

In one embodiment, the Lewis base is piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, 1-methylpyrrolidine, diethylamine, triethylamine , may be any one or two or more selected from tetramethylethylenediamine and methyl-4-pyridinemethylamine, but is not limited thereto.

More preferably, the Lewis base may be any one or two or more selected from 4-dimethylaminopyridine, 1-methylpiperidine and tetramethylethylenediamine.

Preferably, the Lewis base of the present invention may be one or two or more compounds selected from the compounds represented by Chemical Formulas 5 and 6.

In one embodiment of the present invention, the solvent for preparing the Lewis base solution may be used without particular limitation as long as it is a solvent that can dissolve the Lewis base and can be easily removed by volatilization during drying.

In a more specific and non-limiting example, the solvent is chloroform, chlorobenzene, gamma-butyrolactone, formamide, N,N-dimethylformamide, diformamide, acetonitrile, tetrahydrofuran, dimethyl sulfoxide. Side, diethylene glycol, 1-methyl-2-pyrrolidone, N,N-dimethylacetamide, acetone, α-terpineol, β-terpineol, dihydroterpineol, 2-methoxyethanol , acetylacetone, methanol, ethanol, 2-propanol, butanol, pentanol, hexanol, ketone, diethyl ether, toluene and methyl isobutyl ketone may be any one or two or more selected from.

More preferably, the solvent may be any one or two or more selected from chloroform, chlorobenzene, diethyl ether, toluene and 2-propanol.

The heat treatment temperature for the annealing of the Lewis base solution is not particularly limited, but in one embodiment may be performed at a temperature of 50 to 200° C. for 5 minutes to 20 minutes.

More preferably, the annealing of the Lewis base solution may be performed at a temperature of 50 to 150° C., which is a low temperature process, for 5 to 15 minutes.

As described above, the present invention is different from the conventionally known method of adding a Lewis base to a perovskite precursor solution, after preparing a perovskite structure crystal (structure crystal layer), the Lewis base is placed at the grain boundary of the perovskite structure. By passivating the grain boundaries of perovskite through the method of forming base crystals, unlike conventional surface treatment materials, the Lewis base is evenly distributed at the grain boundaries of the perovskite structure crystals, and the Lewis base crystals formed at the grain boundaries are at high temperature. By stably maintaining the passivation of the grain boundaries even in the present invention, the oxidation of metal cations in the perovskite structure is effectively suppressed, and the perovskite structure is stabilized, thereby improving the efficiency of the solar cell.

Hereinafter, a perovskite thin film having a crystallized floating grain boundary according to the present invention and a method for manufacturing the same will be described in more detail through the following preparation examples and examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the present invention. In addition, the unit of additives not specifically described in the specification may be weight %.

[Production Example 1]

Spin-coating a SnO ₂ thin film having a dense structure with a thickness of about 50 nm on a fluorine-containing tin oxide-coated glass substrate (FTO; F-doped SnO ₂ , 8 ohms/cm 2 , Pilkington, hereinafter FTO substrate (first electrode)) was prepared with Specifically, SnCl ₂ ·2H ₂ O was dissolved in IPA at 70 mM, spin-coated at 3000 rpm for 30 seconds, and then heat treated at 150° C. for 30 minutes to control the thickness of the thin film.

[Example 1] Preparation of perovskite solar cell

CH(NH ₂ ) ₂ I (1.4 mmol) and PbI ₂ (1.4 mmol) were dissolved in 1 ml of a mixed solvent of dimethylformamide and dimethyl sulfoxide (dimethylformamide: dimethyl sulfoxide = 4:1 volume ratio), PbBr ₂ (0.07 mmol) was sequentially added to prepare a perovskite precursor solution.

The perovskite precursor solution was spin-coated on the thin SnO ₂ layer prepared in Preparation Example 1 at 1000 rpm for 10 seconds and at 5000 rpm for 50 seconds, and annealed at a temperature of 100° C. for 60 minutes to form a perovskite. A structural crystal layer was formed. At this time, during the second spin coating, 1 ml of diethyl ether was dropped onto the first spin-coated perovskite precursor solution.

A chloroform solution containing 3 mmol of 4-dimethylaminopyridine (DMAP, pKa value in water (25° C.): 9.6) was applied on the perovskite structure crystal layer prepared above, which had been cooled after annealing, and was rotated at 5000 rpm. After spin coating for 30 seconds, it was annealed again at 100° C. for 5 minutes to form 4-dimethylaminopyridine crystals at the grain boundaries of the perovskite structure prepared above.

Bis(trifluoromethane)sulfonimide/acetonitrile (509 mg/ml) and 4-tert butylpyridine were added on the perovskite thin film layer where the Lewis base crystal was formed at the grain boundary of the prepared perovskite structure. A PTAA/chloroform (10.5 mg/ml) solution containing the PTAA/chloroform (10.5 mg/ml) solution was spin-coated at 3000 rpm for 30 seconds to form a hole transport layer.

Finally, Au was vacuum-deposited on the top of the hole transport layer with a thermal evaporator of high vacuum (5x10 ^-6 torr or less) to form an Au electrode (second electrode) having a thickness of about 60 nm, and effective active The area (effective active area) was fixed at 0.096 cm2.

A photograph of the crystals of the DMAP powder in FIG. 1 is shown in (a), and the image of the evaporated DMAP crystals after heating the DMAP powder at 100° C. for 30 minutes is shown in (b), and the peroves prepared in Example 1 When DMAP was used on the skyte thin film, the SEM image bound through the immobilization of the defect is shown in (c).

As shown in FIG. 1, when DMAP is heated at 100 ^o C in a powder state, all of the DMAP is volatilized and does not exist. However, as in Example 1, when DMAP is coated on the perovskite structure crystal layer and heat-treated, the perovskite structure is determined. It can be seen that DMAP crystals are bound to the grain boundary and exist.

Figure 2 shows the time SEM image of the perovskite thin film of Example 1, Figure 3 shows the SEM image of the case of not annealing (annealing) and annealing (a) when applying 4-dimethylaminopyridine .

In particular, when the Lewis base is treated without annealing after forming the perovskite structure crystal from FIG. 3 (pdmap w/o annealing, Comparative Example 1, (a)), the Lewis base is entirely at the grain boundary of the perovskite structure crystal. It can be seen that crystallization of the Lewis base occurs selectively at the grain boundary interface of the perovskite structure crystal when the Lewis base is treated (pdmap w annealing) after annealing after forming a perovskite structure crystal after irregular existence. there is.

In addition, Figure 4 shows the XRD diffraction patterns of DMAP, the perovskite thin film and the perovskite thin film prepared in Example 1.

In addition, it can be seen that DMAP is present on the perovskite thin film through GIWAX measurement of the perovskite thin film prepared in Example 1 in FIG. 10 .

[Examples 2 to 5] Preparation of perovskite thin films

All the processes were the same as in Example 1, but in the step of forming a Lewis base crystal at the grain boundary of the prepared perovskite structure, 5 mmol (Example 2), 10 mmol (Example 3), 15 mmol (Example 4), respectively and 20 mmol (Example 5) of 4-dimethylaminopyridine solution were spin-coated and annealed on the perovskite structure crystals respectively prepared to form 4-dimethylaminopyridine crystals at the grain boundaries of the perovskite structure.

5 shows SEM images of the perovskite thin films prepared in Example 1 (3 mmol), Example 2 (5 mmol), Example 3 (10 mmol), and Example 4 (15 mmol), It can be seen that a Lewis base crystal was formed at the grain boundary of the lobskite structure crystal.

In addition, Figure 6 shows the X-ray diffraction pattern for each concentration of 4-dimethylaminopyridine of the perovskite thin film.

7 is a graph showing the change of TCSPC (Time-Correlated Single Photon Counting) using the perovskite thin film prepared in Examples 2 to 5 of the present invention. It can be seen from Figs. 5 and 6 that a perovskite thin film was formed, and from Fig. 7, as the treatment concentration of DMAP of the present invention increased, defects of the perovskite structure crystal were passivated and the lifespan was increased. there is.

[Comparative Example 1] Preparation of perovskite solar cell

In Example 1, except that the primary heat treatment was not carried out in the step of forming the perovskite structure crystal, in the same manner as in Example 1, except that the perovskite thin film and the same were used. A perovskite solar cell was prepared by carrying out an SEM photograph (pdmap w/o annealing) of the prepared perovskite thin film is shown in FIG. 3 .

[Experimental Example 1] Measurement of characteristics of perovskite solar cells

To measure the current-voltage characteristics of the solar cells prepared in Example 1 and Comparative Example 1, an artificial solar device (ORIEL class A solar simulator, Newport, model 91195A) and a source-meter (Kethley, model 2420) ) was used.

Example 1 Comparative Example 1 Rev. For. Rev. For. V _oc (V) 1.16 1.14 1.07 1.07 J _sc (mA/cm ² ) 24.79 24.78 23.7 23.70 FF(%) 78.08 72.56 78.51 73.13 PCE 22.41 20.50 20.04 18.50

As shown in Table 1, after the perovskite thin film was prepared, a solution to which 4-dimethylaminopyridine, which is a Lewis base, was added was spin-coated and annealed on the finished perovskite structure crystal to form a Lewis base crystal. In the case of Example 1 employing the skyte thin film, it was confirmed that the figure of merit and power generation efficiency were improved compared to Comparative Example 1.

[Experimental Example 2] Measurement of adhesion between the perovskite thin film and the hole transport layer

The bonding force between the perovskite thin film and the hole transport layer formed on the perovskite thin film of the perovskite solar cell prepared in Example 1 was measured by the double cantilever beam (DCB) test method, and the results are shown in FIG. 8 shown in

In addition, the bonding between the perovskite thin film prepared in Comparative Example 1 and the hole transport layer formed on the perovskite thin film was measured in the same manner as above, and the results are shown in FIG. 8 .

As shown in FIG. 8, the adhesion between the perovskite thin film of the present invention and the hole transport layer (indicated by DMAP) is compared with the adhesion between the perovskite thin film and the hole transport layer of Comparative Example 1 (indicated by bare) Thus, it can be seen that the improvement is remarkable. It can be seen that the DMAP present at the grain boundary of the perovskite structure of the perovskite thin film of the present invention improves the adhesion, and the increase in the adhesion force allows the perovskite electronic device to have excellent durability.

[Experimental Example 2] Measurement of adhesion between the perovskite thin film and the hole transport layer

In order to measure the durability of the perovskite solar cell prepared in Example 1 and the perovskite solar cell prepared in Comparative Example 1, the photoelectric conversion efficiency after standing at 85° C. and 85% average relative humidity for 500 hours was measured, and performed a total of 5 times.

The measured results are shown in FIG. 9, and as shown in FIG. 9, the perovskite solar cell of the present invention (indicated by DMAP) is more improved compared to the perovskite solar cell (indicated by control) of Comparative Example 1 It can be seen that it has durability.

As described above, in the present invention, specific matters and limited examples and comparative examples have been described, 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 examples, and the present invention is not limited to the above examples. 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 to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (12)

perovskite structure determination; and A perovskite thin film having a passivated grain boundary comprising; a Lewis base crystal formed at the grain boundary of the perovskite structure crystal. The method of claim 1, The Lewis base is a perovskite thin film having an immobilized grain boundary, characterized in that it is a compound containing any one or two or more electron donor elements selected from N, O and S. 3. The method of claim 2, The Lewis base is a perovskite thin film having a passivated grain boundary, characterized in that the pKa value is 8 or more. The method of claim 1, The Lewis base is piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, 1-methylpyrrolidine, diethylamine, triethylamine, tetramethylethylenediamine And any one or two or more selected from methyl-4-pyridinemethylamine, a perovskite thin film having an immobilized grain boundary. The method of claim 1, The perovskite structure crystal is characterized in that it is formed by heat treatment of a perovskite precursor solution containing a compound satisfying the following formula (1) and a metal halide satisfying the following formula (2), which has a passivated grain boundary lobskite thin film. [Formula 1] AX [Formula 2] mx ₂ In Formulas 1 and 2, A is Cs ⁺ or an organocation; M is selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof; X is Br ^- , Cl ^- or I ^- . 6. The method of claim 5, A of Formula 1 is a compound represented by Formula 3 or Formula 4, a perovskite thin film having a passivated grain boundary. [Formula 3] (R ¹ R ² N=CH-NR ³ R ⁴ ) ⁺ [Formula 4] (R ⁵ R ⁶ R ⁷ R ⁸ N) ⁺ In Formulas 3 and 4, R ¹ to R ⁴ are each independently selected from hydrogen and unsubstituted or substituted (C1-C6)alkyl; R ⁵ to R ⁸ are each independently selected from hydrogen and unsubstituted or substituted (C1-C20)alkyl or unsubstituted or substituted aryl. Forming a perovskite structure crystal by applying a perovskite precursor solution to a substrate and performing primary heat treatment; and A perovskite thin film having a passivated grain boundary comprising; applying a Lewis base solution to the perovskite structure crystal and secondary heat treatment to form a Lewis base crystal at the grain boundary of the perovskite structure crystal manufacturing method. 8. The method of claim 7, The Lewis base solution is a method for producing a perovskite thin film having an immobilized grain boundary, characterized in that it contains a Lewis base having a pKa value of 8 or more. 9. The method of claim 8, The Lewis base is piperazine, morpholine, 4-dimethylaminopyridine, piperidine, 1-methylpiperidine, pyrrolidine, 1-methylpyrrolidine, diethylamine, triethylamine, tetramethylethylenediamine And methyl-4-pyridinemethylamine, characterized in that any one or two or more selected from, the method for producing a perovskite thin film having an immobilized grain boundary. 8. The method of claim 7, The first heat treatment is performed at a temperature of 50 to 300 ℃, the second heat treatment is performed at a temperature of 50 to 150 ℃, a method of manufacturing a perovskite thin film. An electronic device comprising the perovskite thin film of any one of claims 1 to 7. 12. The method of claim 11, The electronic device is a perovskite solar cell

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