WO2017026766A1

WO2017026766A1 - Perovskite having improved moisture stability and photostability, and solar cell using same

Info

Publication number: WO2017026766A1
Application number: PCT/KR2016/008710
Authority: WO
Inventors: 박남규; 이진욱; 김덕환
Original assignee: 성균관대학교산학협력단; 재단법인 멀티스케일 에너지시스템 연구단
Priority date: 2015-08-07
Filing date: 2016-08-08
Publication date: 2017-02-16

Abstract

One embodiment of the present invention relates to a perovskite solar cell production method and a perovskite solar cell comprising a perovskite. The perovskite solar cell production method comprises the step of forming a recombination prevention layer on a first electrode, a perovskite layer comprising a perovskite, a hole transport layer, and a second electrode, wherein the perovskite layer comprising the perovskite formed in the solar cell production method and the perovskite of the perovskite solar cell have the chemical formula (R)_1-yA_yMX₃ and the effect of improving moisture stability and photostabilty.

Description

Perovskite with improved moisture and light stability and solar cell using same

The present application relates to a molecular mobility ionic crystalline perovskite material having improved moisture stability and light stability, and a solar cell using the perovskite material.

Although the photoelectric conversion efficiency (PCE) of state-of-the-art perovskite solar cells has already exceeded 20%, the photo- and / or moisture-stability of organic lead halide perovskite is concerned with further commercialization. In particular, the fundamental weak interaction of organic cations with peripheral iodides due to the eight equivalent orientations of organic cations along the body diagonal in the unit cell, and the organic cations that are not chemically inert, may be the basis of the organic metal halide perovskite. And / or cause water-instability.

Since the initiation of organometallic halide perovskite as a short-lived light harvester in liquid dye-sensitized solar cell structures, the perovskite solar cell's stability has been improved by replacing the liquid electrolyte with a solid state hole transport material. The report on long-term durable solid-state perovskite solar cells has sparked extensive research into the fundamentals of perovskite light harvesters, solar cell device structures, manufacturing processes and materials engineering. As a result, photoelectric conversion efficiency (PCE) has improved rapidly over the years. Recently, 20.1% of PCE has been demonstrated, which ensures that organic lead halide perovskite solar cells are one of the most promising candidates for low cost solar power generation.

The best PCE of perovskite solar cells is known to be due to its advantageous bipolar charge transfer properties with high absorption coefficients in direct bandgap transitions. Perovskite can transport itself photo-generated electron and hole carriers in parallel with the generation of charge at high light harvesting efficiency. This unique optoelectronic characteristic of the organometallic halide perovskite allows for a variety of structures from sensitized systems to mesoscopic or planar heterojunction structures to device structures, which is a new form of solar cells. Classify solar cells. Since the introduction of various device structures, the proliferation of PCE has led to optimization of the synthesis pathway. Alteration of the synthetic pathway leads to high surface coverage and improved crystallinity, with the result that PCE exceeds 20%.

In this regard, Korean Patent No. 1430139 discloses a technology for manufacturing a mesoporous thin film solar cell based on MAPbI ₃ perovskite.

Most of the perovskite solar cells reported so far are based on CH ₃ NH ₃ ⁺ PbI ₃ (MAPbI ₃ ). However, MAPbI ₃ has been reported to undergo a reversible phase transition from tetragonal to cubic phase at 55 ° C. in the range of solar cell operating temperatures. Therefore, the structural phase transition is expected to adversely affect the light stability and thermal stability of the perovskite solar cell. MAPbI ₃ has been reported to be unstable to light and heat due to its low crystallization energy. Recently, lead halide perovskite [HC ⁺ (NH ₂ ) ₂ PbI ₃ , FAPbI ₃ ] based on formamidinium cations has been expanded due to reduced bandgap energy, longer charge diffusion distance and superior light stability. It has been proposed as an alternative to MAPbI ₃ because of its light harvesting capacity. FAPbI ₃ crystallizes in either yellow hexagonal non-perovskite or black trigonal perovskite phase depending on the heat treatment temperature. MAPbI to ₃ in contrast, FAPbI ₃ has been confirmed that there is no phase change at a temperature between 25 ℃ to 150 ℃. 16.01% of PCE was reported using black polymorph FAPbI ₃ in mesoscopic structures, while 14.2% of PCE was demonstrated through planar heterojunction structures.

Despite the many advantages of FAPbI ₃ compared to MAPbI ₃ and, FAPbI ₃ it has not intensively studied. This is due to the instability of FAPbI ₃ with respect to humidity. The instability of the black perovskite FAPbI ₃ is due to the instability of the black phase or formamidinium itself in the presence of water. Although all are stable in a dry atmosphere, the black perovskite FAPbI ₃ is converted to the yellow non-perovskite phase in the presence of a solvent while the formamidinium cation dissociates to ammonia and sym -triazine in the presence of water. Reported. In order to stabilize the black _{_{_{_{FAPbI 3, FA 1- x MA x}}}} PbI 3 or FA _1- _x MA PbI _x ₃ _- _x yi Br _x of mixed cation and / or a halide systems have been proposed. The mixing of the MA cations resulted in stabilization of the black FAPbI ₃ upon enhanced PCE, which was due to the higher dipoles of the MA cations leading to stronger interactions with the PbI ₆ octahedral cage. However, considering the relatively volatile nature of MA cations, mixing of MA cations may not overcome light and thermal stability. In addition, the mixing of bromide will lead to the loss of advantageous narrow bandgap of FAPbI ₃ with phase separation problems.

However, there is no report on perovskite having excellent light stability and water stability.

The present application is to provide a molecular mobility ion crystal material and a method of manufacturing the molecular mobility ion crystal material with improved water stability and light stability.

However, the problem to be solved by the present application is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to a first aspect of the present disclosure, there is provided a method of forming a recombination preventing layer on a first electrode including a conductive transparent substrate; Forming a perovskite layer including perovskite represented by Chemical Formula 1 in the recombination prevention layer; Forming a hole transport layer on the perovskite layer; And forming a second electrode in the hole transport layer.

[Formula 1]

(R) _1-y A _y MX ₃

In Formula 1, R is a substituted or unsubstituted alkyl group, and when R is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, a nitro group or a methoxy group, and A is an alkali metal or an alkaline earth metal And M is selected from the group consisting of Pb, Sn, Ge, and combinations thereof, X is F, Cl, Br, or I and y is greater than 0 to 0.2.

A second aspect of the present application provides a perovskite solar cell, comprising a perovskite represented by the following Chemical Formula 1:

[Formula 1]

(R) _1-y A _y MX ₃

According to one embodiment of the present invention, in the manufacture of the perovskite solar cell, formamide by cubic-octahedral volume reduction by partially replacing the formamidinium cation contained in the perovskite with alkali metal or alkaline earth metal According to the improved interaction between the nium and the iodide, it is possible to obtain a solar cell having improved light stability and water stability of perovskite.

According to one embodiment of the present application, in the perovskite, the mixing density is reduced by mixing the alkali metal or alkaline earth metal, thereby improving the open circuit voltage and filling coefficient, thereby achieving excellent PCE of about 19.0%. can do.

Figure 1, in one embodiment of the present application, shows the structure of a perovskite solar cell.

Figure 2 shows, in one embodiment of the present application, the structure and time-dependent PCE of FAPbI ₃ and FA _1- _x Cs _x PbI ₃ .

3 (a) to 3 (c) show absorbance, X-ray diffraction pattern, and FAPbI ₃ at 630 nm, respectively, of an FA _1-x Cs _x PbI ₃ film coated on glass in one example herein. and FA _0. ₉ Cs _{_0.} Differential scanning calorimetry analysis of ₁ PbI ₃ is shown, and the inset of (a) is a photograph of the film according to the Cs content.

4 (a) and 4 (b) respectively show absorbance and photoluminescence (PL) spectra of an FA _1- _x Cs _x PbI ₃ film spin-coated on a glass substrate without heat treatment in one embodiment of the present application. Inset of (b) shows the photoluminescence spectrum in the narrow wavelength region.

5A to 5D are XRD patterns of FA _1- _x Cs _x PbI ₃ films, respectively, in one embodiment of the present application, and an enlarged 101 of the FA _1- _x Cs _x PbI ₃ films. peak, FAPbI ₃ and FA _0. ₉ Cs _{_0.} _1, the absorption coefficient (α) as a function of wavelength for a PbI _3, and ₃ and FAPbI FA _0. ₉ Cs _{_0.} (Αhv) ² of ₁ PbI ₃ is shown, and the inset in (c) shows α in a narrow wavelength range to show the difference in absorption initiation profile.

(A) and (b) of FIG. 6 show absorbance and normalized PL spectra of FA _1- _x Cs _x PbI ₃ films after heat treatment at 150 ° C. in one example of the present application, respectively, of (a) Inset shows absorbance in the narrow wavelength range.

7A to 7D are surface scanning electron microscope images of (a) FAPbI ₃ and (b) FA _0.9 Cs _0.1 PbI ₃ in one embodiment of the present application, and (c) FAPbI ₃ and ( d) FA _0. ₉ Cs _{_0.} A cross-sectional SEM image of a planar perovskite solar cell to which ₁ PbI ₃ is applied.

(A) and (b) of Figure 8, in one embodiment of the present application, the density (a) FAPbI on the TiO ₂ layer coated on FTO glass _3, and (b) FA _0. ₉ ₀ _Cs. ₁ PbI ₃ Energy dispersive X-ray spectroscopy (EDS) mapping of the film is shown.

Figure 9 is, in one embodiment of the present application, and FA FAPbI ₃ _0. ₉ ₀ _Cs. ₁ PbI ₃ Thermogravimetric Analysis (TGA) was performed in an atmosphere of perovskite.

10A to 10C are statistical distributions of photoelectric conversion efficiency of a perovskite solar cell to which (a) FAPbI ₃ and (b) FA _0.9 Cs _0.1 PbI ₃ are applied in one embodiment of the present application. , and (c) FAPbI ₃ and FA _0. ₉ Cs _{_0.} Shows the current density-voltage (JV) curve of the highest performance device for ₁ PbI ₃ , and the inserted table in (c) shows the short circuit current density (J _sc ), the open circuit voltage (V _oc ) and the filling factor (FF) , And PCE.

(A) and (b) of FIG. 11 are measured in reverse (solid line) and positive (dotted line) scans under one sun illumination (100 mW / cm ² ) of AM 1.5 G in one embodiment of the present application (a) The current density-voltage curve of the perovskite solar cell to which FAPbI ₃ and (b) FA _0.9 Cs _0.1 PbI ₃ is applied.

Figure 12 is, in one embodiment of the present application, FAPbI ₃ and FA _0. ₉ Cs _{_0.} The external quantum efficiency (EQE) spectrum of a perovskite solar cell to which ₁ PbI ₃ is applied is shown.

(A) to (c) of Figure 13, respectively, according to an embodiment of the present application, the FAPbI measured at room temperature and ₃ FA _0. ₉ Cs _{_0.} ₁ PbI ₃ The time constant, capacitance-frequency, and calculated trap density (N _T ) for electron recombination of the perovskite solar cell are shown.

Figure 14 is, in one embodiment of the present application, FAPbI ₃ and FA _0. ₉ Cs _{_0.} The dark current density-voltage curve of the perovskite solar cell to which ₁ PbI ₃ is applied is shown, and the dashed line and the solid line show measured data and fitting results, respectively.

15A and 15B show, in one embodiment of the present application, (a) under a sulfur lamp (relative humidity <50%, temperature <65 ° C.), and (b) as a function of time. ) in (at constant humidity of T = 25 ℃) relative humidity 85%, and ₃ FAPbI FA _0. ₉ Cs _{_0.} Normalized absorbance of ₁ PbI ₃ is shown.

(A) to (d) of FIG. 16, according to one embodiment of the present application, as a function of irradiation time (a) FAPbI _3, (b) FA _0. ₉ ₀ _Cs. _{_{1 PbI 3, (c) FA}} 0. 5 Cs 0. Absorbance spectra of ₅ PbI ₃ , and (d) MAPbI ₃ are shown.

17A and 17B show (a) FAPbI ₃ and (b) FA ₀ stored at 85% relative humidity (dark, T = 25 ° C.) as a function of time in one embodiment of the present application. _{_.} ₉ Cs _{_0.} The absorbance of ₁ PbI ₃ is shown.

18A to 18D show an embodiment of the present application under illumination of continuous white light (about 100 mW / cm ² ) [relative humidity (RH) <50%, temperature (T) <65 ° C. ], Normalized (a) short-circuit current density (J _sc ), (b) opening of encapsulated planar heterojunction perovskite solar cells with FAPbI ₃ (red square) and FA _0.9 Cs _0.1 PbI ₃ (blue circle) Circuit voltage (V _oc ), (c) filling factor (FF), and (d) photoelectric conversion efficiency (PCE).

FIG. 19 shows a current-voltage curve of a perovskite solar cell made by applying a perovskite layer prepared by replacing 10% HC (NH ₂ ) ₂ I with CsI to an inverse structure in an example of the present disclosure. It is shown.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

Throughout this specification, when a part is said to be "connected" with another part, this includes not only the "directly connected" but also the "electrically connected" between other elements in between. do.

Throughout this specification, when a member is located “on” another member, this includes not only when one member is in contact with another member but also when another member exists between the two members.

Throughout this specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding the other components unless otherwise stated. As used throughout this specification, the terms “about”, “substantially”, and the like, are used at, or in close proximity to, numerical values when manufacturing and material tolerances inherent in the meanings indicated are provided, and an understanding of the present application may occur. Accurate or absolute figures are used to assist in the prevention of unfair use by unscrupulous infringers. As used throughout this specification, the term “step of” or “step of” does not mean “step for”.

Throughout this specification, the term "combination (s) thereof" included in the expression of a makushi form refers to one or more mixtures or combinations selected from the group consisting of components described in the expression of makushi form, It means to include one or more selected from the group consisting of the above components.

Throughout this specification, the description of “A and / or B” means “A or B, or A and B”.

Throughout the present specification, the "perovskite" is described as having in the ABX ₃ structure, ABX ₃ structure can be easily estimated based on gongchayul (tolerance factor, t):

t = (r _A + r _X ) / [2 ^1/2 (r _B + r _X )]

Here, r _A and r _B are the effective ion radius of the cations of the cubo-octahedral A and octahedral B sites, and r _X is the anion radius.

Hereinafter, with reference to the accompanying drawings will be described embodiments and embodiments of the present application; However, the present disclosure may not be limited to these embodiments, examples, and drawings.

[Formula 1]

(R) _1-y A _y MX ₃

In Formula 1, R is a substituted or unsubstituted alkyl group, for example, R is a C _1-20 alkyl group, C _1-15 alkyl group, C _1-10 alkyl group, C _1-6 alkyl group, or C _{1 It} may include a _-5 alkyl group, when R is substituted, the substituent is an amino group, hydroxyl group, cyano group, halogen group, nitro group or methoxy group, A is an alkali metal or alkaline earth metal, M is Pb, Sn, Ge, and combinations thereof, X is F, Cl, Br, or I, and y is greater than 0 to 0.2. For example, A may be one selected from the group consisting of Cs, K, Rb, Mg, Ca, Sr, Ba, and combinations thereof, but may not be limited thereto.

In one embodiment of the present application, R may include a linear or branched alkyl group having 1 to 20, 1 to 15, 1 to 10, 1 to 6, or 1 to 5 carbon atoms. For example, R may include methyl, ethyl, propyl, butyl, or pentyl, or an isomer thereof, but may not be limited thereto. In one embodiment of the present application, when R is substituted may be an alkyl group having one or more of the substituents. In one embodiment of the present application, when R is a substituted alkyl group may be substituted by one or more amino groups (-NH ₂ ), for example, one, two, or three amino groups to include It may be, but may not be limited thereto.

In one embodiment of the present application, in Formula 1, R, A, and M may be present in the form of a cation, X may be present in the form of an anion. For example, in Formula 1, R may be a + monovalent organic cation, A may be a + monovalent cation, M is a + divalent cation, X is a-monovalent anion form It may be present as.

In one embodiment of the present application, in Formula 1, R has (R ¹ R ² R ³ R ⁴ N) ⁺ , R ¹ is hydrogen, unsubstituted or substituted C _1-20 alkyl, Or unsubstituted or substituted aryl; R ² is hydrogen, unsubstituted or substituted C _1-20 alkyl, or unsubstituted or substituted aryl; R ³ is hydrogen, unsubstituted or substituted C _1-20 alkyl, or unsubstituted or substituted aryl; And R ⁴ may be hydrogen, unsubstituted or substituted C _1-20 alkyl, or unsubstituted or substituted aryl, but is not limited thereto.

In one embodiment of the present application, in Formula 1, R has Formula (R ⁵ R ⁶ N = CH-NR ⁷ R ⁸ ) ⁺ , and R ⁵ is hydrogen, unsubstituted or substituted C _1-20 alkyl (alkyl) or unsubstituted or substituted aryl; R ⁶ is hydrogen, unsubstituted or substituted C _1-20 alkyl, or unsubstituted or substituted aryl; R ⁷ is hydrogen, unsubstituted or substituted C _1-20 alkyl, or unsubstituted or substituted aryl; And R ⁸ may be hydrogen, unsubstituted or substituted C _1-20 alkyl, or unsubstituted or substituted aryl, but is not limited thereto.

Alkyl groups used throughout this specification may be substituted or unsubstituted, linear or branched chain saturated radicals, which may often be substituted or unsubstituted linear chain saturated radicals, and more often May be an unsubstituted linear chain saturated radical. C ₁ -C ₂₀ alkyl groups are substituted or unsubstituted, linear or branched chain saturated hydrocarbon radicals. Usually C ₁ -C ₁₀ alkyl is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl, or C ₁ -C ₆ alkyl such as methyl, Ethyl, propyl, butyl, pentyl or hexyl, or C ₁ -C ₄ alkyl, for example methyl, ethyl, i-propyl, n-propyl, t-butyl, s-butyl or n-butyl.

When an alkyl group is substituted, it usually has one or more substituents selected from: substituted or unsubstituted C ₁ -C ₂₀ alkyl, substituted or unsubstituted aryl, as defined herein ), Cyano, amino, C ₁ -C ₁₀ alkylamino, di (C ₁ -C ₁₀ ) alkylamino, arylamino, diarylamino, arylalkylamino , Amide, acyllamido, hydroxyl, oxo, halogen, carboxy, ester, acyl, acyloxy, C ₁ -C ₂₀ alkoxy, aryloxy, halogenoalkyl, sulfonic acid, sulfonyl [i.e. thiol, -SH], C ₁ -C ₁₀ alkyl Alkylthio, arylthio, sulfonyl, phosphoric acid, phosphate ester, phosphonic acid and phospho Sites ester (phosphonate ester).

Examples of substituted alkyl groups include halogenalkyl, hydroxyalkyl, aminoalkyl, alkoxyalkyl, and alkaryl groups. The term alkalyl as used herein belongs to a C ₁ -C ₂₀ alkyl group in which at least one hydrogen atom is substituted with an aryl group. Examples of each group include benzyl [phenylmethyl, PhCH _2- ], benzhydryl (Ph ₂ CH-), trityl [triphenylmethyl, Ph ₃ C-], phenethyl [phenylethyl, Ph-CH ₂ CH _2- ], styryl (Ph CH = CH-), cinnamin (Ph CH = CH CH ₂ -), But not limited to them.

Usually substituted alkyl groups have one, two or three, for example one or two substituents.

An aryl group is a monocyclic or bicyclic aromatic group, substituted or unsubstituted, which group contains 6 to 14 carbon atoms, preferably 6 to 10 carbon atoms in the ring portion. It is common to include carbon atoms. Examples include phenyl, naphthyl, indenyl, and indanyl groups. Ali groups are unsubstituted or substituted. When an aryl group as defined above is substituted, it generally has one or more substituents selected from: unsubstituted C ₁ -C ₆ alkyl [forms an aralkyl group], unsubstituted Aryl, cyano, amino, C ₁ -C ₁₀ alkylamino, di (C ₁ -C ₁₀ ) alkylamino, arylamino, diarylamino, arylalkylamino, amide (amido), acyllamido, hydroxyl, halogen, carboxy, ester, acyl, acyloxy, C ₁ -C ₂₀ alkoxy, aryloxy, halogenoalkyl , Sulfhydryl [ie thiol, -SH], C ₁ -C ₁₀ alkylthio, arylthio, sulfonic acid, phosphoric acid, phosphate Phosphate esters, phosphonic acids, and sulfonyl groups.

Usually it has 0, 1, 2, or 3 substituents. Substituted aryl groups may be combined with a single C ₁ -C ₆ alkylene group or with the formula —X— (C ₁ -C ₆ ) alkylene, or —X— (C ₁ -C ₆ ) alkylene- May be substituted at two positions with a bidentate group represented by X-, where X is selected from O, S and NR, and R is H, aryl or C ₁ -C ₆ alkyl . Thus, the substituted aryl group may be a cycloalkyl group or a aryl group fused with a heterocyclyl group. The ring atoms of an aryl group may contain one or more heteroatoms (as heteroaryl groups). The aryl group (or heteroaryl group) is a substituted or unsubstituted mono or bicyclic heterocyclic aromatic group, which aromatic group comprises one or more heteroatoms It is common to include 6 to 10 atoms in the part. It is usually a 5- or 6-parted ring and contains at least one heteroatom selected from O, S, N, P, Se and Si. It may, for example, comprise 1, 2 or 3 heteroatoms. Examples of heteroaryl groups are pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl, thienyl, pyrazolidinyl , Pyrrolyl, oxazolyl, oxadiazolyl, isoxazolyl, thiadiazolyl, thiazolyl, isothiazolyl, isozozolyl, imidazolyl (imidazolyl), pyrazolyl, quinolyl, and isoquinolyl. Heteroaryl groups may be unsubstituted or substituted, for example, as defined for aryl above. Usually it has 0, 1, 2 or 3 substituents.

In this regard, Figure 1 is a schematic diagram showing the structure of a perovskite solar cell according to an embodiment of the present application.

The solar cell including the perovskite according to the exemplary embodiment of the present disclosure may include a sensitive structure, a mesoscopic structure, or a heterojunction structure, but may not be limited thereto.

1, the perovskite solar cell according to the exemplary embodiment of the present application includes a first electrode 10 including a conductive transparent substrate, a recombination preventing layer 20 formed on the first electrode 10, and the The perovskite layer 30 formed on the recombination prevention layer 20, the hole transfer layer 40 formed on the perovskite layer 30, and the second electrode 50 formed on the hole transfer layer 40 are formed. It may include.

The perovskite solar cell according to the exemplary embodiment of the present disclosure may have a sandwich structure in which two electrodes, that is, the first electrode 10 and the second electrode 50 are bonded to each other, but are not limited thereto. Can be. For example, the first electrode 10 may be represented as a working electrode or a semiconductor electrode, and the second electrode 50 may be represented as a counter electrode, but is not limited thereto. You may not.

In one embodiment of the present disclosure, the conductive transparent substrate is indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin-based oxide, zinc oxide, and It may be a glass substrate or a plastic substrate containing a material selected from the group consisting of combinations thereof, but may not be limited thereto. The conductive transparent substrate may be used without particular limitation so long as it has a material having conductivity and transparency. For example, the plastic substrate may include one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyimide, triacetyl cellulose, and combinations thereof, but is not limited thereto. You may not.

In one embodiment of the present application, the conductive transparent substrate may include a doped with a metal selected from the group consisting of Group 3 metal, for example, Al, Ga, In, Ti, and combinations thereof, This may not be limited.

In one embodiment of the present application, the recombination prevention layer 20 may include an organic semiconductor, an inorganic semiconductor, or a mixture thereof, but may not be limited thereto. For example, the recombination prevention layer 20 may include a metal oxide selected from the group consisting of TiO ₂ , SnO ₂ , ZnO, WO ₃ , Nb ₂ O ₅ , TiSrO ₃ , and combinations thereof. This may not be limited.

In one embodiment of the present application, forming the perovskite layer 30, MX ₂ (wherein M is selected from the group consisting of Pb, Sn, Ge, and combinations thereof, and X Is F, Cl, Br, or I) and the precursor for preparing perovskite (R) _1-y A _y X [where R is a substituted or unsubstituted alkyl group, and when R is substituted, the substituent Is an amino group, hydroxyl group, cyano group, halogen group, nitro group or methoxy group, A is alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca, Sr, Ba), and X is F, Cl, Br , Or I, and y is greater than 0 to 0.2], which may be performed by coating the recombination prevention layer 20.

In one embodiment of the present application, the precursor (R) _1- _y A _y X for perovskite preparation is a ratio of the equivalent of RX in the RX-containing solution and the equivalent of AX in the AX-containing solution (1- y): As y, the y may be formed by mixing to be greater than 0 to 0.2, but may not be limited thereto.

In one embodiment of the present application, by partially replacing the precursor for preparing perovskite with the alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca, Sr, Ba), having a three-dimensional RMX ₃ structure The R-site of the perovskite may be one that hybridizes organic-inorganic cations. In one embodiment of the present application, by partially replacing the precursor for producing the perovskite with the alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca, Sr, Ba), the precursor for producing the perovskite The cubic-octahedral volume of is reduced. As a result, the interaction between cations [FA ⁺ ] and iodide of the precursor for preparing perovskite may be improved, and thus, light stability and moisture of the perovskite solar cell according to the exemplary embodiment of the present application. Stability can be improved.

In one embodiment of the present application, the precursor for preparing perovskite is [HC (NH ₂ ) ₂ ] _1-y A _y X (where A is an alkali metal or alkaline earth metal, X is F, Cl, Br, Or I, y is greater than 0 to 0.2), but may not be limited thereto.

In one embodiment of the present application, the precursor for preparing perovskite may include [HC (NH ₂ ) ₂ ] _1-y Cs _y I (where y is greater than 0 to 0.2), but is not limited thereto. It may not be.

In one embodiment of the present application, the perovskite layer is [HC (NH ₂ ) ₂ ] _1- _y A _y MX ₃ [where A is an alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca , Sr, Ba), M is selected from the group consisting of Pb, Sn, Ge, and combinations thereof, X is F, Cl, Br, or I, and y is greater than 0 to 0.2] It may be included, but may not be limited thereto.

In one embodiment of the present application, the perovskite layer is [HC (NH ₂ ) ₂ ] _1- _y A _y PbX ₃ [where A is an alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca , Sr, Ba), X is F, Cl, Br, or I, y is greater than 0 to 0.2], but may not be limited thereto.

In one embodiment of the present application, the perovskite layer may include [HC (NH ₂ ) ₂ ] _1- _y Cs _y PbI ₃ (where y is greater than 0 to 0.2), but is not limited thereto. You may not.

In one embodiment of the present application, coating the MX ₂ and the (R) _1-y A _y X to the recombination prevention layer is to be carried out by spin coating, doctor braid, screen printing, vacuum deposition, or spray coating It may be, but may not be limited thereto.

In one embodiment of the present application, the perovskite layer may be formed on the recombination prevention layer, and may further include heat treatment at about 50 ° C. to about 200 ° C., but may not be limited thereto. For example, the heat treatment may include about 50 ° C. to about 200 ° C., about 80 ° C. to about 200 ° C., about 110 ° C. to about 200 ° C., about 140 ° C. to about 200 ° C., about 170 ° C. to about 200 ° C., about 50 ° C. To about 170 ° C, about 50 ° C to about 140 ° C, about 50 ° C to about 110 ° C, or about 50 ° C to about 80 ° C, but may not be limited thereto.

Subsequently, a hole transport layer (HTM) 40 may be formed on the perovskite layer 30. The second electrode 50 may be formed in the hole transport layer 40. The hole transport layer 40 may be formed for the purpose of reducing the oxidized photoactive layer 30, but may not be limited thereto.

In one embodiment of the present application, the hole transport layer 40 may include a single molecule hole transport material or a polymer hole transport material, but may not be limited thereto. For example, as the single molecule hole transport material, spiro-MeOTAD [2,2 ', 7,7'-tetrakis (N, Np-dimethoxy-phenylamino) -9,9'-spirobifluorene] may be used. P3HT [poly (3-hexylthiophene)], polytriarylamine (PTAA), or poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) may be used as the polymer hole transport material, but is not limited thereto. Also, for example, the hole transport layer 40 may be a dopant selected from the group consisting of Li-based dopants, Co-based dopants, and combinations thereof as the doping material, but may not be limited thereto. . For example, as the hole transport material, spiro-MeOTAD, 4-tert-Butylpyridine (tBP), trifluoromethane (sulfonimide) lithium salt (Li-TFSI), or a mixture thereof may be used, but may not be limited thereto. .

According to one embodiment of the present application, the second electrode 50 is made of Pt, Au, Ni, Cu, Ag, In, Ru, Pd, Rh, Ir, Os, C, conductive polymer, and combinations thereof It may include one selected from the group, but may not be limited thereto. For example, by using gold (Au), which is a highly stable metal, as the second electrode, long-term stability of the perovskite solar cell of the present application may be improved, but may not be limited thereto.

[Formula 1]

(R) _1-y A _y MX ₃

In Formula 1, R is a substituted or unsubstituted alkyl group, for example, R is a C _1-20 alkyl group, C _1-15 alkyl group, C _1-10 alkyl group, C _1-6 alkyl group, or C _{1 It} may include a _-5 alkyl group, when the R is substituted, the substituent is an amino group, hydroxyl group, cyano group, halogen group, nitro group or methoxy group, A is an alkali metal (Cs, K, Rb) or alkali Earth metal (Mg, Ca, Sr, Ba), M comprises one selected from the group consisting of Pb, Sn, Ge, and combinations thereof, X is F, Cl, Br, or I, y is 0 Greater than or equal to 0.2.

In one embodiment of the present application, in Formula 1, R, A, and M may be present in the form of a cation, X may be present in the form of an anion.

With respect to the perovskite solar cell according to the second aspect of the present application, detailed descriptions of portions overlapping with the first side of the present application are omitted, but the contents described in the first aspect of the present application are the same as the second side of the present application. Can be applied.

In one embodiment of the present invention, in Formula 1, R may include a linear or branched alkyl group having 1 to 20, 1 to 15, 1 to 10, 1 to 6, or 1 to 5 carbon atoms. For example, R may include methyl, ethyl, propyl, butyl, or pentyl, or an isomer thereof, but may not be limited thereto. In one embodiment of the present application, when R is substituted may be an alkyl group having one or more of the substituents. In one embodiment of the present application, when R is a substituted alkyl group may be substituted by one or more amino groups (-NH ₂ ), for example, one, two, or three amino groups to include It may be, but may not be limited thereto.

In one embodiment of the present application, the perovskite solar cell, a first electrode comprising a conductive transparent substrate; A recombination prevention layer formed on the first electrode; A perovskite layer comprising perovskite represented by Formula 1 formed on the recombination preventing layer; A hole transport layer formed on the perovskite layer; And a second electrode formed on the hole transport layer, but may not be limited thereto.

In one embodiment of the present application, by partially replacing the perovskite precursor contained in the perovskite with the alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca, Sr, Ba), 3 The R-site of the perovskite having a dimensional RMX ₃ structure may be one of hybridization of an organic-inorganic cation. In one embodiment of the present application, by partially replacing the precursor for producing the perovskite with the alkali metal (Cs, K, Rb) or alkaline earth metal (Mg, Ca, Sr, Ba), the precursor for producing the perovskite The cubic-octahedral volume of is reduced. As a result, the interaction between cations [FA ⁺ ] and iodide of the precursor for preparing perovskite may be improved, and thus, light stability and moisture of the perovskite solar cell according to the exemplary embodiment of the present application. Stability can be improved.

In one embodiment of the present application, the perovskite layer is AX-containing 0 to 20 parts by weight of the RX-containing solution, relative to 100 parts by weight of the MX ₂ -containing solution and RX-containing solution in the anti-recombination layer It may be formed by coating the (R) _1- _y A _y X-containing solution formed by replacing with a solution, but may not be limited thereto.

In one embodiment of the present application, the perovskite layer may include [HC (NH ₂ ) ₂ ] _1- _y A _y MX ₃ (where y is greater than 0 to 0.2), but is not limited thereto. You may not.

Hereinafter, the embodiments of the present application will be described in detail. However, the present application may not be limited thereto.

[[ 실시예Example ] ]

1.Synthesis of HC (NH ₂ ) ₂ I

HC (NH ₂ ) ₂ I (FAI) was synthesized by reaction of 30 mL hydroiodic acid (57 wt% in water, Sigma-Aldrich) with 15 g of formaminium acetate (99%, Aldrich) at 0 ° C. . After stirring for 2 hours, the dark yellow precipitate was recovered by evaporating the solvent at 60 ° C. using a rotary evaporator. The solid was washed with ether and recrystallized from ethanol. The resulting white precipitate was dried under vacuum for 24 hours and stored in a glove box filled with Ar.

2. Perovskite Solar Cell Manufacturing

Fluorine-doped tin oxide (FTO) glass substrates (Pilkington, TEC-8, 8Ω / sq) were washed with detergent and subjected to UV-ozone treatment by sonication in ethanol bath for 15 minutes. About 60 nm thick dense TiO ₂ layer was deposited on the FTO substrate by spin-coating three repeated 0.1 M 1-butanol (Aldrich, 99.8%), titanium diisopropoxide bis (acetylacetonate) solutions. . Between each coating, the substrate was dried on a hot plate at 125 ° C. for 5 minutes and finally annealed at 500 ° C. for 20 minutes after completion of spin-coating. The dense TiO ₂ -coated FTO glass was treated with UV-ozone for 10 minutes before spin-coating the perovskite solution. Perovskite solution was prepared in 600 mg of N, N-dimethylformamide (DMF) (Sigma-Aldrich, 99.8%) and 1 mmol of PbI ₂ (461 mg, Aldrich, 99%), FAI (0.172 mg), And dimethyl sulfoxide (DMSO) (78 mg, Sigma,> 99.9%). For FA _1-x Cs _x PbI ₃ , the corresponding amount of CsI (Aldrich, 99.9%) was added instead of FAI. The solution was filtered by a syringe filter (Whatman) with a 0.45 μm pore size. 30 μL of the perovskite solution was spin-coated at 4,000 rpm for 30 seconds and dropped after 10 seconds on a substrate on which 500 μL of diethyl ether (SAMCHUN, 99.0%) was spun. The substrate was heat treated at 50 ° C. for 3 minutes and at 15 ° C. for 5 minutes. The spiro-MeOTAD solution consists of 28.8 μL of 4-tert-butyl pyridine and 17.5 μL of lithium bis (trifluoromethanesulfonyl) imide solution [520 mg LITSFI (Sigma-Aldrich, 99.8%) in 1 mL of acenitrile]. Prepared by dissolving 72.3 mg of spiro-MeOTAD in 1 mL of chlorobenzene added. spiro-MeOTAD was deposited by dropping 20 μL of the spiro-MeOTAD solution onto a substrate rotating at 3,000 rpm. For the counter electrode, Ag was thermally evaporated at a deposition rate of 0.3 kW / s for about 110 minutes. Au electrode was used for long term stability test.

[실험예]Experimental Example

1. Characteristics

The current density-voltage curve is a Keithley 2400 source meter under one solar light (AM 1.5G, 100 mW / cm ² ) simulated by a solar simulator (Oriel Sol 3A classAAA) with a 450 W Xenon lamp (Newport 6280NS). It was measured using. Light intensity was adjusted by NREL-corrected Si solar cells equipped with KG-2 filters. During the measurement, the device was covered with a metal aperture mask with an active area of 0.125 cm ² . External quantum efficiency (EQE) was measured by a specially designed EQE system (PV measurement Inc.). Monochromatic beams were generated from 75 W Xenon source lamps (USHIO, Japan). EQE data was collected in DC mode without bias light. The time limited photocurrent response was monitored with a monochrome beam of 530 nm at 4 Hz. Absorption coefficients were calculated from the transmittance and reflectivity of the perovskite film coated on the glass. Both transmittance and reflectance were measured by a UV-vis spectrometer equipped with an integrating sphere (Perkinelmer, lamda35). The thickness of the perovskite film was measured by an alpha-step IQ surface profiler (KAL Tencor). Differential scanning calorimetry analysis was measured by DSC7020 (Seico Inst.). X-ray diffraction patterns were measured by Bruker AXS (D8 advance, Bruker Corporation) using Cu Kα radiation at a scan rate of 4 ° / min. The time constants for electron transfer and recombination were measured with weak laser pulses at 532 nm by superimposing relatively large bias illumination at 680 nm using the transient photocurrent-voltage measurement setup described elsewhere. The diffusion coefficient was calculated using the time constant for electron transfer and the thickness of the perovskite film. Admittance spectroscopy measurements were performed by potentiometer / constant current method (PGSTAT 128N, Autolab, Eco-Chemie) under dark conditions. To avoid unintended effects by bias voltage on capacitance, 20 mV AC sinusoidal pulses with frequencies from 1 Hz to 1 MHz were used without other DC voltages. In order to x-axis transform from angular frequency to E _ω [= kT ln (2ν ₀ / ω)], the trial-to-ejection frequency (ν ₀ ) is frequency dependent via a relaxation process instead of the Arrhenius plot of the characteristic frequency. Calculated from the phosphor capacitance plot.

2. Sample for stability evaluation

To test the stability of the _{_{_{film, FAPbI 3, FA 0. 9 Cs}}} 0. _{_{_{_{1 PbI 3, FA 0. 5 MA}}}} 0. ₅ PbI ₃ , and MAPbI ₃ films were deposited by spin coating each precursor solution onto dense-TiO ₂ coated FTO glass. FA _0. ₅ MA _{_0.} ₅ PbI ₃ and MAPbI ₃ For the solution, the corresponding amount of CH ₃ NH ₃ I (MAI) was added to the precursor solution in place of FAI. The device for evaluation of stability was prepared by depositing spiro-MeOTAD and Au, as described above. Encapsulation of the device was performed using a UV-curable adhesive (foto polymer, SECURE CP-7233D) with a Tor seal (VARIN). During the measurement at 30 minute intervals, the device was subsequently exposed to white light produced by a 730 W sulfur lamp (LG electronics, PSH0731B).

3. Optical stability

_{_{_{_{FAPbI 3, FA 0. 9 Cs 0}}}} . _{_{_{_{1 PbI 3, FA 0. 5 MA}}}} 0. ₅ PbI ₃ , and MAPbI ₃ The film was exposed to the white light produced by the 730 W sulfur lamp. The temperature of the film was measured at about 60 ° C. while the relative humidity (RH) was less than 50%.

4. Moisture stability

_{_{_{_{FAPbI 3, FA 0. 9 Cs 0}}}} . ₁ PbI ₃ The film was stored in a constant humidity and temperature chamber in the dark, adjusted to have humidity and temperature of 25 ° C. and RH 85%, respectively.

[결과][result]

3 (a) shows the absorbance of a FA _1- _x Cs _x PbI ₃ film coated on glass at 630 nm as a function of _x . Without adding cesium iodide (CsI) to the precursor solution (x = 0), the film exhibits low absorbance at 630 nm because it absorbs little at full wavelength [FIG. 4 (a)], which shows FAPbI ₃ of pure non-due to formation of the perovskite yellow. As x increases, the color of the film gradually changes to yellowish dark brown. As a result, the absorbance increases at 630 nm and reaches its maximum at x = 0.1 (FA _0.9 Cs _0.1 PbI ₃ ) and then decreases with higher x. The change in color of the film indicates the formation of different phases. In order to examine the image of the film, the X-ray diffraction (XRD) pattern of the film was measured and shown in FIG. For x = 0 (FAPbI ₃ ), a pure yellow phase was formed. However, when the mixing phase the highest portions on the black color of yellow, and black FAPbI ₃ is detected in the _{_{x = 0.1 (FA 0. 9 Cs}} 0. 1 PbI 3), is formed by the addition of CsI. When x is greater than 0.1, the CsPbI ₃ phase begins to appear with the black FAPbI ₃ phase. FIG FA in _{_{_{4 (b) 0. 9 Cs 0}}} . The highest PL intensity of ₁ PbI ₃ also supports the highest portion of the black FAPbI ₃ phase formed at x = 0.1. In Figure 3 (c), differential scanning calorimetry analysis (differential scanning calorimetry, DSC) is FA _0. ₉ Cs _{_0.} _It is measured to investigate the thermodynamic behavior of ₁ PbI ₃ . For FAPbI ₃ , the peak at 106.5 ° C. was due to the phase transition from yellow to black, whereas the endothermic peak at 89 ° C. was thought to be due to solvent evaporation. In contrast to FAPbI _3, FA _0. ₉ Cs _{_0.} ₁ PbI ₃ did not show additional peaks except those observed at lower temperatures of 81.3 ° C. Indeed when the FA _0.9 Cs _0.1 PbI ₃ film is heated to 80 ° C., completely black perovskite is formed.

The XRD pattern of the 150 ° C.-annealed FA _1- _x Cs _× PbI ₃ film is shown in FIG. 5 (a). CsPbI ₃ peaks begin to appear at x = 0.15 and 0.20, while when x is 0, 0.05 and 0.10, a black phase of FAPbI ₃ is detected. Absorbance and normalized photoluminescence (PL) spectra of the FA ₁ _- _x Cs _x PbI ₃ film show that the onset of absorption at x = 0.05 is blue region while about 10 nm blue-shift is observed at x = 0.10, 0.15, and 0.20. Slightly shifted is shown in FIG. 6. Normalized PL peaks show 5 nm blue-shift for x = 0.05 and 18 nm blue-shift for x = 0.10, 0.15 and 0.20. x = 0.10, 0.15, and 0.20 in consideration of the occurrence of CsPbI ₃ peak in the XRD pattern for the absorption with the same start and the PL peak position of the film x = 0.15 and 0.20, FA _0. ₉ Cs _{_0.} A mixed phase of ₁ PbI ₃ and CsPbI ₃ will be formed for x = 0.15 and 0.20. Interestingly, the 110 and 220 peak is greatly improved with respect to x = 0.1, this FA _0. ₉ Cs _{_0.} _{It means that 1} PbI ₃ film is highly oriented in the (110) axis. The (101) peak in the XRD pattern of FA _1- _x Cs _x PbI ₃ is fitted with a Gaussian distribution function in FIG. 5 (b) to determine the position of peak maximum and full width at half maximum (FWHMs). The position of the peak maximum was determined to be 14.00 °, 13.98 °, 14.07 °, 14.04 °, and 14.01 °, for x = 0, 0.05, 0.10, 0.15 and 0.20, respectively. FAPbI ₃ with all peaks tending to be the same It originated from the move. The shift of the peak maximum towards higher angles for x = 0.10, 0.15 and 0.20 indicates a decrease in the lattice parameter. The lattice parameter of FAPbI ₃ (x = 0) is calculated as a = 8.9377 mm ₃ and c = 11.0098 mm ³ , resulting in a unit cell volume of 761.2263 mm ³ , which is a = 8.9817 mm ^{3 with} a unit cell volume of 768.9 mm ³ And a reported value of c = 11.0060 mm 3. The peak for x = 0.10 shifts to a significantly higher angle where the lattice parameter is calculated as a = 8.9116 ms and c = 10.9763 ms, corresponding to a unit cell volume of 749.4836 mm 3. The change in lattice parameters is estimated by FA ⁺ 's (2.79 Å; DFT calculations), which results in a reduction of the cubic-octahedral volume for the A-site cation surrounded by the corner shared by the 8 PbI ₆ octahedron in the unit cell. Compared to), probably due to the mixing of a smaller ion radius of Cs ⁺ (1.81 mm 3). Shrinkage of the cubic-octahedral volume for the A-site cation leads to a strong interaction between the A-site cation and the iodide, which is due to the presence of the black perovskite phase at relatively low temperatures upon mixing of Cs in FAPbI ₃ . (Fig. 3). FWHMs were calculated as 0.2743, 0.2568, 0.1735, 0.1752 and 0.2438 for x = 0, 0.05, 0.10, 0.15 and 0.20, respectively. Overall, FWHMs reduced by the addition of CsI means an improvement in crystallinity according to the Scherrer equation, where further increases in CsI in amounts of x = 0.15 and 0.20 result in increased FWHMs of CsPbI ₃ impurities. This may be due to formation. FAPbI ₃ and FA _0. ₉ Cs _{_0.} The absorption coefficient of ₁ PbI ₃ is calculated from the reflectance, transmittance, and film thickness in FIG. 5C. FA ₀ _.9 Cs _0.1 PbI ₃ shows a slightly higher absorption coefficient at the wavelength of visible light to near infrared range, in which the absorption start is shifted to a lower wavelength by about 10 nm. Absorption start and the PL peak in both the blue-because movement to indicate the change in optical band gap (Eg), the researchers have used the Kubellka-munk FAPbI equation ₃ and FA _0. ₉ Cs _{_0.} Egs of ₁ PbI ₃ are determined (FIG. 5 (d)). FAPbI ₃ and FA _0. ₉ Cs _{_0.} Egs of ₁ PbI ₃ are determined to be 1.53 eV and 1.55 eV, respectively. A slight increase in Eg is associated with strong Pb-I interactions as a result of reduced lattice parameters.

(A) and (b) of Figure 7 is compact TiO ₂ layer coated FTO (fluorine-doped tin oxide) on the glass ₃ and FAPbI FA _0. ₉ Cs _{_0.} Scanning electron microscope (SEM) images of ₁ PbI ₃ film are shown. The FA _0.9 Cs _0.1 PbI ₃ film shows large crystals with clear grain boundaries, while the FAPbI ₃ film shows a relatively small crystal hierarchy with unclear grain boundaries. The relatively large crystal size is significantly related to the XRD patterns of Figs. 5A and 5B. From FAPbI ₃ FA _0. ₉ Cs _{_0.} ₁ different from the morphology of PbI ₃ also, as shown in (c) and (d) of Figure 7, can be observed in the cross-sectional images of the entire cell, FA _0. ₉ Cs _{_0.} _{The 1} PbI ₃ film shows larger crystals whose grain boundaries are perpendicular to the substrate. In Figure 8 FA _0. ₉ Cs _{_0.} ₁ element distribution map of PbI ₃ film is Cs atoms entire FA _0. ₉ Cs _{_0.} It was confirmed that it was uniformly distributed on the ₁ PbI ₃ film. Nominal Composition FA _0. ₉ Cs _{_0.} The realistic stoichiometry of ₁ PbI ₃ is inferred from its thermal gravimetric analysis (TGA) curve for that obtained from FAPbI ₃ (FIG. 9). Both perovskites suffer significant weight loss upon heat treatment at 350 ° C. due to the sublimation of the organic components of HC (NH ₂ ) ₂ I. FA _0. ₉ Cs _{_0.} The small weight loss (~ 3%) of ₁ PbI ₃ is due to CsI (or CsPbI ₃ ) remaining stable up to 600 ° C. From the weight loss, the composition of the 10% film of FAI replaced by CsI is calculated as FA _0.884 Cs _0.116 PbI ₃ , which is similar to the nominal composition (FA _0.9 Cs _0.1 PbI ₃ ).

FA _0. ₉ Cs _{_0.} The photovoltaic performance of perovskite solar cells using ₁ PbI ₃ is compared to that of the initial FAPbI ₃ in FIG. 10. Data was obtained in reverse scan at a scan rate of 0.11 V / s. The measured data is summarized in Table 1 and Table 2 below.

TABLE 1

TABLE 2

Compared with FAPbI ₃ based perovskite solar cells (16.3 ± 0.667%) the average photoelectric conversion efficiency (PCE) of, FA _0. ₉ Cs _{_0.} Perovskite solar cells containing ₁ PbI ₃ exhibit 4.9% higher average PCE (17.1 ± 0.753%), with a slight increase in short-circuit current density (J _sc ) and open circuit voltage (V _oc ). Primarily due to a 3.9% increased fill factor (FF, 0.697 ± 0.17 to 0.724 ± 0.016). As it can be seen in Figure 11, FAPbI ₃ and FA _0. ₉ Cs _{_0.} _{Both 1} PbI ₃ perovskite solar cells exhibit a similar degree of JV hysteresis due to the planar structure. The current density-voltage (JV) curve of the highest performance device is shown in FIG. 10 (c) and shows 17.4% PCE for FAPbI ₃ (J _sc = 23.0 mA / cm ² , V _oc = 1.05 V, FF = 0.721) the FA _0. ₉ Cs _{_0.} Significantly improved to 19.0% (J _sc = 23.4 mA / cm ² , V _oc = 1.07 V, FF = 0.759) for ₁ PbI ₃ . The external quantum efficiency (EQE) spectrum of the device is shown in FIG. 12. The integrated J _sc is calculated to 13.30 mA / cm ² for each FAPbI ₃ FA _0. ₉ Cs _{_0.} Calculated at 16.97 mA / cm ² for ₁ PbI ₃ , which is measured from the solar simulator J _sc Much lower than The low J _sc calculated from the EQE spectra may be due to the limitation of the measurement system for planar heterojunction structures.

In FIG. 13, the recombination kinetics of the perovskite solar cell was investigated from the transient photovoltage collapse profile. As it can be seen in the _{_{13 (a), FA 0. 9}} Cs 0. ₁ page lobe having a PbI ₃ Sky bit solar cell as compared to that of FAPbI ₃ showed a longer time constant with respect to recombination (τ _R), which is slightly higher than that of FA _0. ₉ Cs ₀ FAPbI _{_3.} _{It is} related to V _oc of ₁ PbI ₃ perovskite solar cell. The origin of other recombinant kinetics was investigated by dark current measurement (FIG. 14). Shunt and series resistances are obtained from reverse slopes near the zero bias and V _oc regions, respectively. The ideal coefficient n and the saturation current J ₀ are calculated by applying data to equation (1).

Where J _D , V _b , q, k _B and T represent the current density, bias voltage, electron charge, Boltzmann constant and temperature, respectively. The fitting results are summarized in Table 2 above. FA _0.9 Cs _0.1 PbI ₃ perovskite while the shunt resistor is responsible for the high FF of the solar cells increased almost three times from 20399.84 to ^{_{64683.05 Ω · cm 2, FA 0.}} 9 Cs 0. _1, the series resistance for PbI ₃ is lower _{FAPbI 3 46% (8.16 Ω ·} cm 2) than for the (14.93 Ω · cm ^2). J _0, and n is for each _{^{FAPbI 3 3.32 × 10 -6 mA /}} cm 2 and 2.91, and FA _0. ₉ Cs _{_0.} _It is determined to be 3.45 × 10 ⁻⁷ mA / cm ² and 2.53 for ₁ PbI ₃ . High and low R _sh J ₀ is FA _0. ₉ Cs _{_0.} _{It is} associated with the high V _oc of ₁ PbI ₃ perovskite solar cells. To explain the origin of high shunt resistance and low saturation current density, admittance spectroscopy measurements were performed (FIGS. 13B and 13D).

Using the admittance spectroscopy, FAPbI ₃ and FA _0. ₉ Cs _{_0.} The trapping density (N _T ) of ₁ PbI ₃ is estimated using equation (2) by the angular frequency dependent capacitance [Fig. 13 (b)],

Where V _bi is the internal diffusion potential, W is the depletion width, C is the capacitance, ω is the frequency, k is the Boltzmann constant, and T is the temperature. As described elsewhere, V _bi and W are obtained from the C ^-2 -V plot. As shown in (b) of Figure 13, FA _0.9 Cs _0.1 PbI ₃ as compared to FAPbI _3, nearly single-digit showed a low trapping density, which FAPbI ₃ to Cs mixed successfully valence band (E _ω = E of _T -E _V , where E _T and E _V are the trap energy and valence band edges, respectively, to reduce the overall capture state and thus enhance FF and V _oc . The N _T peak near E _ω = 0.15 eV in FAPbI ₃ is generally due to shallow capture, which shows a value similar to MAPbI ₃ . The origin of E _ω = 0.3 eV near the unique deep capture is not yet known, but it may be from electrode polarization at the interface that appears to be closely related to hysteresis.

FA _0. ₉ Cs _{_0.} The light and water stability of the ₁ PbI ₃ film is evaluated in comparison to that of FAPbI ₃ . FIG. 15 shows absorbance normalized at 630 nm as a function of time (see full absorption spectra in FIGS. 16 and 17). For the light stability tests, FAPbI ₃ FA and _0. ₉ formed in the dense phase -TiO ₂ layer coated on FTO glass Cs _{_0.} ₁ PbI ₃ film was prepared by exposure to continuous white light illumination using a sulfur lamp with an intensity of about 100 mW / cm ² . The absorbance of both films gradually decreased and the decrease was significant after about 10 hours (FIG. 15A), which may be due to a gradual increase in substrate temperature up to 60 ° C. However, FAPbI film ₃ (85.9% degradation) is FA _0. ₉ Cs _{_0.} After 19 hours compared to ₁ PbI ₃ (65.0% degradation), more severe degradation is shown. Herein, FA _0. ₅ MA _{_0.} The light stability of ₅ PbI ₃ and MAPbI ₃ was also compared (FIG. 16). In the case of MAPbI ₃ , the color of the film is completely bleached within 1 hour upon exposure to white light. In addition, when replacing 50% of the cation with FA MA cation _{_{_{_{_{(FA 0. 5 MA 0. 5}}}}} PbI 3), the color of the film can not avoid the degradation that is completely bleached after 8 hours. The mechanism of photo-induced degradation of MAPbI ₃ in atmospheric conditions has been reported to be due to the production of HI by protons released from MA cations. However, in the case of FAPbI ₃ , the extent to which protons are released is expected to be less than in the case of MA cations because FA ⁺ ions are stabilized by the resonance properties of CN bonds. The partial substitution of Cs ⁺ for FA ⁺ is not leading to more improvement of the light stability due to the generation of rational HI is will be quenched (quenching) by a CsI. For the moisture stability test, both films are exposed to 85% relative humidity (RH) at 25 ° C. (dark conditions). As compared to FAPbI _3, for 7 hours FA _0. ₉ Cs _{_0.} _When much more severe degradation (77.8%) was observed for FAPbI ₃ than degradation of ₁ PbI ₃ (49.9%), FA _0.9 Cs _0.1 PbI ₃ shows a relatively good stability with respect to humidity [Fig. 15 (b) ]. As demonstrated by XRD in FIG. 3, because of the low stability of FAPbI ₃ to humidity caused by the conversion from black to yellow or accelerated dissociation of formamidinium cations to ammonia and sym-triazines, The mixing of 10% Cs stabilizes the black FAPbI ₃ at a relatively low temperature and the FA _0.9 Cs _0.1 PbI ₃ is expected to be more stable since the Cs cation hardly undergoes dissociation. In addition, FA _0. ₉ Cs _{_0.} The improved light and moisture stability of ₁ PbI ₃ is related to the reduced lattice parameters associated with the more tightly enclosed FA cations by Cs doping.

Finally, the stability of the entire cell of the device was investigated when the device was encapsulated under Ar atmosphere. As it is shown in Figure 18, FA _0. ₉ Cs _{_0.} Devices using ₁ PbI _{3 show} much better stability than earlier FAPbI ₃ based devices. FA ₀ _.9 _0.1 Cs ₃ PbI-based, while the _SC J, V _oc, FF and the PCE of the device, each deterioration of 35%, 1.6% (improvement), 16.9% and 45.2%, FAPbI ₃ J _sc , V _oc , FF and PCE for the device degraded 70.3%, 72.9%, 42.6% and 95.4%, respectively. Encapsulation was performed under Ar atmosphere in the glove box, but H ₂ O or O ₂ may not be completely removed even in the Ar purged glove box. In addition, the transmission of O ₂ and H ₂ O cannot be ruled out during prolonged exposure to light without cooling in atmospheric conditions. FAPbI ₃ based on more than FA _0. ₉ Cs _{_0.} ₁ PbI ₃ The good stability of perovskite solar cells can be attributed to better intrinsic stability to light and humidity, as observed in FIG. 15. Since the possibility of ion interlocking and molecular motion of FA cations as a factor influencing stability cannot be ruled out, related research is ongoing.

In conclusion, FA _0. ₉ Cs _{_0.} Highly efficient planar heterojunction perovskite solar cells with ₁ PbI ₃ have been successfully produced by Lewis base additions of PbI ₂ . Average PCE improved from 16.3% to 17.1% by partial substitution of Cs cations for FA cations due to suppressed charge recombination, and the highest PCE of 19.0% in reverse scan measurements was FA _0.9 Cs _0.1 PbI ₃ based perovskite Achieved from solar cells. Suppressed charge recombination is due to the reduced trap density near the valence band maximum value, resulting in an increase in shunt resistance and a decrease in saturation current. FA ₀ _. ₉ Cs ₀ _. The light and water stability of ₁ PbI ₃ was found to be significantly improved compared to the initial FAPbI ₃ . Part of a mixed Cs ions in the FA- site Cubic - led to the collapse of the octahedral volume, thereby FA _0. ₉ Cs _{_0.} ₁ Improves (FA-I) interactions primarily responsible for the improved stability of PbI ₃ . As a result, perovskite solar cells using FA _0.9 Cs _0.1 PbI ₃ demonstrated superior stability over FAPbI ₃ based devices under continuous illumination.

The above description of the present application is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present application is indicated by the following claims rather than the above description, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present application.

Claims

Forming a recombination prevention layer on the first electrode including the conductive transparent substrate;

Forming a perovskite layer including perovskite represented by Chemical Formula 1 in the recombination prevention layer;

Forming a hole transport layer on the perovskite layer; And,

Forming a second electrode on the hole transport layer

Including, a perovskite solar cell manufacturing method:

[Formula 1]

(R) 1- y A y MX 3

In Formula 1,

R is a substituted or unsubstituted alkyl group, and when R is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, a nitro group or a methoxy group,

A is an alkali metal or alkaline earth metal,

M includes one selected from the group consisting of Pb, Sn, Ge, and combinations thereof,

X is F, Cl, Br, or I,

y is greater than 0 to 0.2.
The method of claim 1,

Forming the perovskite layer includes MX 2 , wherein M is selected from the group consisting of Pb, Sn, Ge, and combinations thereof, and X is F, Cl, Br, or I And precursor (R) 1- y A y X for producing perovskite, wherein R is a substituted or unsubstituted alkyl group, and when R is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, A nitro group or a methoxy group, A is an alkali metal or alkaline earth metal, X is F, Cl, Br, or I, and y is greater than 0 to 0.2) perovskite Method for manufacturing sky solar cell.
The method of claim 2,

The precursor for preparing perovskite is [HC (NH 2 ) 2 ] 1- y A y X (where A is an alkali metal or an alkaline earth metal, X is F, Cl, Br, or I, and y is greater than 0 To 0.2), wherein the method of manufacturing a perovskite solar cell.
The method of claim 2,

The precursor for producing perovskite is [HC (NH 2 ) 2 ] 1- y C y y (where y is greater than 0 to 0.2), the method of manufacturing a perovskite solar cell.
The method of claim 2,

The coating of the MX 2 and the (R) 1- y A y X on the anti-recombination layer is performed by spin coating, doctor braid, screen printing, vacuum deposition, or spray coating, perovskite solar cell Method of preparation.
The method of claim 1,

The perovskite layer is [HC (NH 2 ) 2 ] 1- y A y MX 3 (where y is greater than 0 to 0.2), the method of manufacturing a perovskite solar cell.
The method of claim 1,

The perovskite layer is a method of manufacturing a perovskite solar cell, including [HC (NH 2 ) 2 ] 1- y Cs y PbI 3 (where y is greater than 0 to 0.2).
The method of claim 1,

Forming the perovskite layer on the recombination prevention layer, and further comprising heat treatment at 50 ℃ to 200 ℃, manufacturing method of a perovskite solar cell.
A perovskite solar cell comprising a perovskite represented by Formula 1 below:

[Formula 1]

(R) 1- y A y MX 3

In Formula 1,

R is a substituted or unsubstituted alkyl group, and when R is substituted, the substituent is an amino group, a hydroxyl group, a cyano group, a halogen group, a nitro group or a methoxy group,

A is an alkali metal or alkaline earth metal,

M includes one selected from the group consisting of Pb, Sn, Ge, and combinations thereof,

X is F, Cl, Br, or I,

y is greater than 0 to 0.2.
The method of claim 9,

The perovskite solar cell,

A first electrode comprising a conductive transparent substrate;

A recombination prevention layer formed on the first electrode;

A perovskite layer comprising perovskite represented by Formula 1 formed on the recombination preventing layer;

A hole transport layer formed on the perovskite layer; And,

A second electrode formed on the hole transport layer

That includes, perovskite solar cell.
The method of claim 9,

The perovskite layer was formed by replacing 0 to 20 parts by weight of the RX-containing solution with an AX-containing solution relative to 100 parts by weight of the MX 2 -containing solution and the RX-containing solution in the recombination preventing layer (R). A perovskite solar cell, which is formed by coating a 1- y A y X-containing solution.
The method of claim 9,

The perovskite layer is a perovskite solar cell comprising [HC (NH 2 ) 2 ] 1- y A y MX 3 (where y is greater than 0 to 0.2).
The method of claim 9,

The perovskite layer is a perovskite solar cell comprising [HC (NH 2 ) 2 ] 1- y Cs y PbI 3 (where y is greater than 0 to 0.2).