KR102613202B1 - Copolymer and organic solar cell comprising the same - Google Patents

Abstract

A unit represented by the following formula (1); It relates to a copolymer containing units and conjugated monomers represented by Formula 2 and an organic solar cell containing the same.

Description

Copolymer and organic solar cell comprising the same {COPOLYMER AND ORGANIC SOLAR CELL COMPRISING THE SAME}

This specification relates to copolymers and organic solar cells containing the same.

Organic solar cells are devices that can directly convert solar energy into electrical energy by applying the photovoltaic effect. Solar cells can be divided into inorganic solar cells and organic solar cells depending on the materials that make up the thin film. A typical solar cell is made by doping crystalline silicon (Si), an inorganic semiconductor, into a p-n junction. Electrons and holes created by absorbing light diffuse to the p-n junction and are accelerated by the electric field to move to the electrode. The power conversion efficiency of this process is defined as the ratio of the power given to the external circuit and the solar power input to the solar cell, and has been achieved up to 24% when measured under currently standardized virtual solar irradiation conditions. However, since conventional inorganic solar cells already show limitations in economics and material supply and demand, organic semiconductor solar cells that are easy to process, inexpensive, and have a variety of functions are attracting attention as a long-term alternative energy source.

It is important to increase the efficiency of solar cells so that they can output as much electrical energy as possible from solar energy. In order to increase the efficiency of these solar cells, it is important to generate as many excitons as possible inside the semiconductor, but it is also important to bring the generated charges to the outside without loss. One of the causes of charge loss is the disappearance of generated electrons and holes through recombination. Various methods have been proposed to transfer the generated electrons or holes to the electrode without loss, but most require additional processes, which may increase manufacturing costs.

Two-layer organic photovoltaic cell (C.W.Tang, Appl. Phys. Lett., 48, 183 (1986))

This specification provides a copolymer and an organic solar cell containing the same.

An exemplary embodiment of the present specification includes a unit represented by the following formula (1);

A unit represented by the following formula (2); and

A copolymer comprising a conjugated monomer is provided.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

of formula 1 and of Formula 2 above are different from each other,

R1 and R2 are the same or different from each other and are each independently a heterocyclic group substituted with a silyl group,

R3 and R4 are the same or different from each other, and are each independently a hydroxy group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Substituted or unsubstituted aryloxy group; Or a substituted or unsubstituted heterocyclic group,

X1 to

R and R' are the same or different from each other and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

Another embodiment of the present specification includes a first electrode;

a second electrode provided opposite the first electrode; and

It is provided between the first electrode and the second electrode, and includes one or more organic layers including a photoactive layer,

An organic solar cell is provided wherein at least one of the organic layers includes the copolymer.

The copolymer according to an exemplary embodiment of the present specification has excellent solubility.

The copolymer according to an exemplary embodiment of the present specification may have the effect of reducing the band gap and/or increasing the amount of light absorption. Accordingly, when applied to an organic solar cell, high current value (Isc) and excellent efficiency can be achieved.

The copolymer according to an exemplary embodiment of the present specification realizes high efficiency and has appropriate solubility, so it has an economical advantage in terms of time and/or cost when manufacturing a device.

The copolymer according to an exemplary embodiment of the present specification can be used alone or mixed with other materials in an organic solar cell.

1 is a diagram showing an organic solar cell according to an exemplary embodiment of the present specification.
Figure 2 is a diagram showing the UV measurement results of Copolymer 1.
Figure 3 is a diagram showing the UV measurement results of Copolymer 2.
Figure 4 is a diagram showing the UV measurement results of Copolymer 3.
Figure 5 is a diagram showing the UV measurement results of Copolymer 4.
Figure 6 is a diagram showing the UV measurement results of Copolymer 5.
Figure 7 is a diagram showing the UV measurement results of Copolymer 6.

Hereinafter, this specification will be described in detail.

An exemplary embodiment of the present specification includes a unit represented by the following formula (1);

A unit represented by the following formula (2); and

A copolymer comprising a conjugated monomer is provided.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

of formula 1 and of Formula 2 above are different from each other,

R1 and R2 are the same or different from each other and are each independently a heterocyclic group substituted with a silyl group,

R3 and R4 are the same or different from each other, and are each independently a hydroxy group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Substituted or unsubstituted aryloxy group; Or a substituted or unsubstituted heterocyclic group,

X1 to

R and R' are the same or different from each other and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the present specification, the unit represented by Formula 1 and the unit represented by Formula 2 are different from each other. Specifically, the formula 1 and of Formula 2 above are different from each other. More specifically, R1 and R2 in Formula 1 are heterocyclic groups substituted with silyl groups, and R3 and R4 in Formula 2 do not include heterocyclic groups substituted with silyl groups.

In one embodiment of the present specification, the copolymer includes both a unit containing a heterocyclic group substituted with a silyl group (Formula 1) and a unit not containing a silyl group (Formula 2). Accordingly, both the effects that can be shown by including a silyl group and the effects that can be shown by not including a silyl group can be shown.

In one embodiment of the present specification, Formula 1 represents s*(Si)-p*(C) bond interaction by including a heterocyclic group substituted with a silyl group. Accordingly, the HOMO level may decrease and V _oc may increase, and the extinction coefficient may increase and J _sc may increase. In addition, mobility and J _sc can be improved by improving crystallinity and improving intermolecular interactions.

In one embodiment of the present specification, Formula 2 has the effect of improving solubility by not containing a silyl group, so the solubility of the copolymer is improved and the morphology is easily controlled when manufacturing a device. Accordingly, the performance of the device is improved.

As used herein, “unit” refers to a repeating structure included in a copolymer. In other words, “unit” may mean a structure included in the form of two or more groups in a copolymer through a polymerization reaction. The unit may be included in the main chain of the copolymer to form a copolymer.

In this specification, “including a unit” means included in the main chain of the copolymer.

In this specification, means a site that is bonded to another substituent, monomer, or binding site.

In the present specification, a monomer may refer to a repeating unit or a substance that becomes a unit included in a copolymer. For example, the conjugated monomer in a copolymer may refer to a repeating unit derived from the conjugated monomer.

In this specification, “combination” means connecting multiple one structures or connecting different types of structures.

As used herein, “origin” means that a bond between at least two adjacent elements in a copolymer is broken, or a new bond is created when a hydrogen or substituent is removed. The repeating unit derived from the conjugated monomer may refer to a unit forming one or more of the main chain and side chain of the copolymer.

Examples of substituents in this specification are described below, but are not limited thereto.

In this specification, the term “substituted or unsubstituted” refers to deuterium; halogen group; Nitrile group; imide group; amide group; carbonyl group; ester group; hydroxyl group; Alkyl group; Cycloalkyl group; Alkoxy group; alkenyl group; Alkylthio group; silyl group; Amine group; Aryl group; Aryloxy group; and a heterocyclic group, or is substituted with a substituent in which two or more of the above-exemplified substituents are linked, or does not have any substituent. For example, “a substituent group in which two or more substituents are connected” may be a biphenyl group. That is, the biphenyl group may be an aryl group, or it may be interpreted as a substituent in which two phenyl groups are connected.

In this specification, the halogen group may be fluorine, chlorine, bromine, or iodine.

In the present specification, the alkyl group may be straight chain or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 30. Specific examples include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl. , isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n -heptyl, 1-methylhexyl, octyl, n-octyl, tert-octyl, n-decyl, n-dodecyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2- Dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, 4-methylnonane, 4-ethylnonane, 5-methylhexyl, 5-methylundecane, 5- Examples include ethyl undecane, 5-propyl undecane, 7-methylpentadecane, and 7-ethylpentadecane, but are not limited thereto.

In the present specification, the alkylthio group can be represented as -SR ₂₀₀ , and R ₂₀₀ is an alkyl group.

In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 30 carbon atoms, specifically cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, and cyclohexyl. , 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, etc., but are limited to these. It doesn't work.

In the present specification, the alkoxy group may be straight chain, branched chain, or ring chain. The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably 1 to 30 carbon atoms. Specifically, methoxy, ethoxy, n-propoxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentyloxy, neopentyloxy, Isopentyloxy, n-hexyloxy, 3,3-dimethylbutyloxy, 2-ethylbutyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, benzyloxy, p-methylbenzyloxy, etc. It may be possible, but it is not limited to this.

In the present specification, the aryl group may be monocyclic or polycyclic.

When the aryl group is a monocyclic aryl group, the number of carbon atoms is not particularly limited, but is preferably 6 to 30 carbon atoms. Specifically, the monocyclic aryl group may be a phenyl group, a biphenyl group, or a terphenyl group, but is not limited thereto.

If the aryl group is a polycyclic aryl group, the number of carbon atoms is not particularly limited. It is preferable to have 10 to 30 carbon atoms. Specifically, the polycyclic aryl group may be a naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, perylenyl group, chrysenyl group, fluorenyl group, etc., but is not limited thereto.

In the present specification, the heterocyclic group includes one or more non-carbon atoms and heteroatoms, and specifically, the heteroatoms may include one or more atoms selected from the group consisting of O, N, Se, and S. . The number of carbon atoms is not particularly limited, but is preferably 2 to 30 carbon atoms, and the heterocyclic group may be monocyclic or polycyclic. Examples of heterocyclic groups include thiophene group, furanyl group, pyrrole group, imidazolyl group, thiazolyl group, oxazolyl group, oxadiazolyl group, pyridyl group, bipyridyl group, pyrimidyl group, triazinyl group, and triazinyl group. Zolyl group, acridyl group, pyridazinyl group, pyrazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group , isoquinolinyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, benzocarbazolyl group, benzothiophene group, dibenzothiophene group, benzofuranyl group, pe Examples include, but are not limited to, phenanthroline, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, phenothiazinyl, and dibenzofuranyl.

In the present specification, the silyl group may be represented as -SiR ₁₀₀ R ₁₀₁ R ₁₀₂ , and R ₁₀₀ , R ₁₀₁ and R ₁₀₂ are the same or different, and each independently represents a substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or it may be selected from the group consisting of substituted or unsubstituted heterocyclic groups. For example, the silyl group may specifically be trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group, and phenylsilyl group. It is not limited to this.

In the present specification, the alkenyl group may be straight chain or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 30. Specific examples include vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1- Butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-( Naphthyl-1-yl) vinyl-1-yl, 2,2-bis (diphenyl-1-yl) vinyl-1-yl, stilbenyl group, styrenyl group, etc., but are not limited thereto.

In this specification, the aryl group of the aryloxy group is the same as the example of the aryl group described above. Specifically, aryloxy groups include phenoxy group, p-toryloxy group, m-toryloxy group, 3,5-dimethyl-phenoxy group, 2,4,6-trimethylphenoxy group, p-tert-butylphenoxy group, 3- Biphenyloxy group, 4-biphenyloxy group, 1-naphthyloxy group, 2-naphthyloxy group, 4-methyl-1-naphthyloxy group, 5-methyl-2-naphthyloxy group, 1-anthryloxy group , 2-anthryloxy group, 9-anthryloxy group, 1-phenanthryloxy group, 3-phenanthryloxy group, 9-phenanthryloxy group, etc., and arylthoxy groups include phenylthyloxy group and 2-phenanthryloxy group. These include, but are not limited to, methylphenylthioxy group and 4-tert-butylphenylthioxy group.

In the present specification, the description of the alkenyl group described above can be applied, except that the alkenylene group is a divalent group.

In the present specification, the description of the aryl group described above may be applied, except that the arylene group is a divalent group.

In the present specification, the description of the heterocyclic group described above can be applied, except that the divalent heterocyclic group is a divalent group.

In one embodiment of the present specification, the copolymer includes a structure represented by the following formula (3).

[Formula 3]

In Formula 3,

f is the mole fraction, which is a real number 0<f<1,

g is the mole fraction, which is a real number 0<g<1,

f+g=1,

n is an integer from 1 to 10,000,

E1 and E2 are the same or different from each other and are each independently a conjugated monomer,

X1 to

and are different from each other,

R1 and R2 are the same or different from each other and are each independently a heterocyclic group each substituted with a silyl group,

R3 and R4 are the same or different from each other, and are each independently a hydroxy group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Substituted or unsubstituted aryloxy group; Or a substituted or unsubstituted heterocyclic group,

R and R' are the same or different from each other and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

However, when R3 and R4 are substituted heterocyclic groups, R3 and R4 are not substituted with a silyl group.

In one embodiment of the present specification, R1 and R2 are each a thiophene group substituted with a silyl group.

In an exemplary embodiment of the present specification, the unit represented by Formula 1 is represented by the following Formula 1-1.

[Formula 1-1]

In Formula 1-1,

X1 and X2 are the same or different from each other and are each independently CRR', NR, O, SiRR', PR, S, GeRR', Se or Te,

R10 to R15 are the same as or different from each other, and are each independently a substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

R and R' are the same or different from each other and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In one embodiment of the present specification, the copolymer includes a structure represented by the following Chemical Formula 3-1.

[Formula 3-1]

In Formula 3-1,

f is the mole fraction, which is a real number 0<f<1,

g is the mole fraction, which is a real number 0<g<1,

f+g=1,

n is an integer from 1 to 10,000,

E1 and E2 are the same or different from each other and are each independently a conjugated monomer,

X1 to

R3 and R4 are the same or different from each other, and are each independently a hydroxy group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Substituted or unsubstituted aryloxy group; Or a substituted or unsubstituted heterocyclic group,

R10 to R15 are the same as or different from each other, and are each independently a substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

R and R' are the same or different from each other and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

However, when R3 and R4 are substituted heterocyclic groups, R3 and R4 are not substituted with a silyl group.

In one embodiment of the present specification, R3 and R4 are not heterocyclic groups substituted with a silyl group.

In an exemplary embodiment of the present specification, X1 to

In an exemplary embodiment of the present specification, X1 to X4 are each S.

In an exemplary embodiment of the present specification, R3 and R4 are the same as or different from each other, and are each independently a substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the present specification, R3 and R4 are the same as or different from each other, and are each independently a substituted or unsubstituted alkoxy group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the present specification, R3 and R4 are the same as or different from each other, and are each independently an alkoxy group substituted or unsubstituted by an alkyl group; Or SR ₂₀₀ is a heterocyclic group substituted with one or more of an alkyl group, a halogen group, and a heterocyclic group, and R ₂₀₀ is an alkyl group.

In an exemplary embodiment of the present specification, R10 to R15 are the same as or different from each other, and each independently represents a substituted or unsubstituted alkyl group.

In an exemplary embodiment of the present specification, R10 to R15 are the same as or different from each other, and each independently represents an alkyl group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, the unit represented by Formula 2 is represented by any one of the following Formulas 2-1 to 2-3.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

In Formulas 2-1 to 2-3,

a and b are each integers from 1 to 4,

When a and b are 2 or more, the substituents in parentheses are the same or different from each other,

R50 to R59 are the same or different from each other, and are each independently hydrogen; halogen group; Alkylthio group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the present specification, R50 to R55 are the same or different from each other, and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Or it is a substituted or unsubstituted alkylthio group.

In an exemplary embodiment of the present specification, R50 and R53 are the same or different from each other, and are each independently a substituted or unsubstituted alkyl group; Or it is a substituted or unsubstituted alkylthio group.

In an exemplary embodiment of the present specification, R50 and R53 are the same or different from each other, and are each independently a straight-chain or branched-chain alkyl group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, R50 and R53 are the same or different from each other, and each independently represents an alkylthio group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, R51 and R54 are the same as or different from each other, and are each independently hydrogen; Or it is a halogen group.

In an exemplary embodiment of the present specification, R51 and R54 are the same as or different from each other, and are each independently hydrogen; Or fluorine.

In an exemplary embodiment of the present specification, R52 and R55 are each hydrogen.

In an exemplary embodiment of the present specification, R56 and R57 are the same or different from each other, and each independently represents a substituted or unsubstituted alkyl group.

In an exemplary embodiment of the present specification, R56 and R57 are the same or different from each other, and are each independently a straight-chain or branched-chain alkyl group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, R58 and R59 are the same or different from each other, and are each independently hydrogen; Or it is a substituted or unsubstituted alkyl group.

In an exemplary embodiment of the present specification, R58 and R59 are the same or different from each other, and are each independently hydrogen; or a straight-chain or branched-chain alkyl group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, the unit represented by Formula 2 is represented by any of the following structures.

As used herein, “conjugated monomer” refers to a monomer containing a structure in which two or more multiple bonds exist between one single bond and exhibit interaction with each other.

In one embodiment of the present specification, the conjugated monomer includes a combination of one or two or more groups among a substituted or unsubstituted alkenylene group, a substituted or unsubstituted arylene group, and a substituted or unsubstituted divalent heterocyclic group. do.

In an exemplary embodiment of the present specification, the conjugated monomer includes any one or a combination of two or more of the following structures.

In the above structure,

_{X10 to _ _ _ _ _ _}

R20 to R33, R _d and R _e are the same or different from each other, and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the present specification, the conjugated monomer includes any one or a combination of two or more of the following structures.

_{In the above structure , X10 to _}

R20 to R27, R30, R31, R _d and R _e are the same or different from each other, and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the present specification, the conjugated monomer has any one of the following structures.

_{In the above structure , X10 to e} ,

R20 to R27, R30, R31, R30', R31', R _d and R _e are the same or different from each other, and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or it is a substituted or unsubstituted heterocyclic group.

In an exemplary embodiment of the _{present specification} , X10 to

In one embodiment of the present specification, X10 is S.

In an exemplary embodiment of the present specification, X12 is NR _d , and R _d is a substituted or unsubstituted alkyl group.

In one embodiment of the present specification, X19 and X19' are each S.

In an exemplary embodiment of the present specification, R20 to R27, R30, R31, R30', and R31' are the same or different from each other, and are each independently hydrogen; halogen group; Substituted or unsubstituted alkyl group; Or it is a substituted or unsubstituted aryl group.

In an exemplary embodiment of the present specification, R20 and R21 are the same as or different from each other, and each independently represents a substituted or unsubstituted alkyl group.

In an exemplary embodiment of the present specification, R20 and R21 are the same as or different from each other, and each independently represents a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, R20 and R21 are the same or different from each other, and are each independently a branched chain alkyl group having 1 to 30 carbon atoms.

In an exemplary embodiment of the present specification, R22 and R23 are the same as or different from each other, and are each independently hydrogen; Or it is a halogen group.

In an exemplary embodiment of the present specification, R22 and R23 are each fluorine.

In an exemplary embodiment of the present specification, R24 and R25 are the same as or different from each other, and each independently represents a substituted or unsubstituted aryl group.

In an exemplary embodiment of the present specification, R24 and R25 are the same or different from each other, and each independently represents an aryl group substituted with an alkoxy group.

In an exemplary embodiment of the present specification, R24 and R25 are the same or different from each other, and each independently represents a phenyl group substituted with an alkoxy group.

In an exemplary embodiment of the present specification, R26 and R27 are the same or different from each other and are each independently a halogen group.

In an exemplary embodiment of the present specification, R26 and R27 are the same or different from each other and each is fluorine.

In one embodiment of the present specification, R30, R31, R30', and R31' are each hydrogen.

In an exemplary embodiment of the present specification, the conjugated monomer has any one of the following structures.

In one embodiment of the present specification, the copolymer includes any one of the following structures.

In one embodiment of the present specification, n is an integer from 1 to 10,000.

In one embodiment of the present specification, n is an integer from 2 to 5,000.

In one embodiment of the present specification, n is an integer from 5 to 1,000.

In an exemplary embodiment of the present specification, the number average molecular weight of the copolymer is 5,000 g/mol to 1,000,000 g/mol.

In one embodiment of the present specification, the terminal group of the copolymer is a substituted or unsubstituted heterocyclic group; Or it is a substituted or unsubstituted aryl group.

In one embodiment of the present specification, the end group of the copolymer is benzo[1,2-b:4,5-b']dithiophenyltrimethylstanane (benzo[1,2-b:4,5- b']dithiophenyltrimethylstannane group or bromo-thiophene group.

An exemplary embodiment of the present specification includes: a first electrode;

a second electrode provided opposite the first electrode; and

It is provided between the first electrode and the second electrode, and includes one or more organic layers including a photoactive layer,

An organic solar cell is provided wherein at least one of the organic layers includes the copolymer.

In one embodiment of the present specification, the photoactive layer includes the copolymer.

In one embodiment of the present specification, the photoactive layer includes an electron donor and an electron acceptor, and the electron donor includes the copolymer.

In one embodiment of the present specification, the electron acceptor may be selected from the group consisting of fullerene, fullerene derivative, basocuproine, semiconducting element, semiconducting compound, non-fullerene, and combinations thereof. Specifically, the electron acceptor material is ITIC (3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno [2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene), PC ₆₀ BM(phenyl C ₆₀ -butyric acid methyl ester) , PC ₆₁ BM (phenyl C ₆₁ -butyric acid methyl ester) or PC ₇₁ BM (phenyl C ₇₁ -butyric acid methyl ester).

In one embodiment of the present specification, the electron donor and electron acceptor constitute a bulk heterojunction (BHJ).

Bulk heterojunction means that electron donor materials and electron acceptor materials are mixed together in the photoactive layer.

In one embodiment of the present specification, the electron donor and electron acceptor may be mixed at a weight ratio of 1:10 to 10:1. Specifically, electron donors and electron acceptors may be mixed at a weight ratio of 1:1 to 1:10, and more specifically, electron donors and electron acceptors may be mixed at a weight ratio of 1:1 to 1:5. If necessary, the electron donor and electron acceptor may be mixed at a weight ratio of 1:1 to 1:3.

In one embodiment of the present specification, the organic solar cell may further include an additional organic material layer. The organic solar cell can reduce the number of organic material layers by using organic materials that have multiple functions simultaneously.

In one embodiment of the present specification, the organic solar cell includes one or two or more organic material layers selected from the group consisting of a hole injection layer, a hole transport layer, a hole blocking layer, a charge generation layer, an electron blocking layer, an electron injection layer, and an electron transport layer. It further includes.

In one embodiment of the present specification, the organic material layer includes a hole transport layer, a hole injection layer, or a layer that performs hole transport and hole injection simultaneously, and the hole transport layer, the hole injection layer, or a layer that performs hole transport and hole injection simultaneously Includes the above copolymer.

In another embodiment, the organic material layer includes an electron injection layer, an electron transport layer, or a layer that performs electron injection and electron transport simultaneously, and the electron injection layer, the electron transport layer, or a layer that performs electron injection and electron transport simultaneously Includes the above copolymer.

In one embodiment of the present specification, the organic solar cell includes a first electrode, a photoactive layer, and a second electrode. The organic solar cell may further include a substrate, a hole transport layer, and/or an electron transport layer.

In one embodiment of the present specification, the organic solar cell further includes a substrate, an electron transport layer, and a hole transport layer.

1 shows a substrate 10, a first electrode 20, an electron transport layer 30, a photoactive layer 40, a hole transport layer 50, and a second electrode 60 according to an embodiment of the present specification. This is a diagram showing an organic solar cell.

In one embodiment of the present specification, the first electrode is an anode and the second electrode is a cathode. In another embodiment of the present specification, the first electrode is a cathode and the second electrode is an anode.

In one embodiment of the present specification, the organic solar cell has a normal structure. In the normal structure, a substrate, a first electrode, a hole transport layer, an organic material layer including a photoactive layer, an electron transport layer, and a second electrode may be stacked in that order.

In one embodiment of the present specification, the organic solar cell has an inverted structure. In the inverted structure, a substrate, a first electrode, an electron transport layer, an organic material layer including a photoactive layer, a hole transport layer, and a second electrode may be stacked in that order.

In this specification, the substrate may be a glass substrate or a transparent plastic substrate with excellent transparency, surface smoothness, ease of handling, and waterproofness, but is not limited thereto, and is not limited to any substrate commonly used in organic solar cells. Specifically, there are glass, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene), PI (polyimide), and TAC (triacetyl cellulose). It is not limited to this.

The first electrode may be made of a transparent and highly conductive material, but is not limited thereto. Metals such as vanadium, chromium, copper, zinc, gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); Combinations of metals and oxides such as ZnO:Al or SnO ₂ :Sb; Conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene](PEDOT), polypyrrole, and polyaniline are included, but are not limited to these.

The method of forming the first electrode is not particularly limited, but is applied to one side of the substrate or in the form of a film using, for example, sputtering, E-beam, thermal evaporation, spin coating, screen printing, inkjet printing, doctor blade, or gravure printing. It can be formed by coating.

When forming the first electrode on a substrate, it may undergo cleaning, moisture removal, and hydrophilic modification processes.

For example, the patterned ITO substrate was sequentially cleaned with a detergent, acetone, and isopropyl alcohol (IPA), and then washed on a heating plate at 100°C to 150°C for 1 minute to 30 minutes, preferably at 120°C for 10 minutes to remove moisture. After drying and completely cleaning the substrate, the surface of the substrate is modified to be hydrophilic.

Through the surface modification described above, the bonding surface potential can be maintained at a level suitable for the surface potential of the photoactive layer. Additionally, during modification, the formation of a polymer thin film on the first electrode may become easier and the quality of the thin film may be improved.

Pretreatment techniques for forming the first electrode include a) a surface oxidation method using parallel plate discharge, b) a method of oxidizing the surface through ozone generated using UV ultraviolet rays in a vacuum, and c) a method of oxidizing the surface using plasma. There is a method of oxidation using the generated oxygen radicals.

One of the above methods can be selected depending on the state of the first electrode or substrate. However, whichever method is used, it is generally desirable to prevent oxygen escape from the surface of the first electrode or substrate and to suppress the remaining moisture and organic matter as much as possible. At this time, the practical effect of pre-processing can be maximized.

As a specific example, a method of oxidizing the surface through ozone generated using UV light can be used. At this time, after ultrasonic cleaning, the patterned ITO substrate is baked on a hot plate and dried well, then placed in a chamber, and a UV lamp is applied to produce ozone generated when oxygen gas reacts with UV light. The patterned ITO substrate can be cleaned.

However, the method for modifying the surface of the patterned ITO substrate in this specification does not need to be particularly limited, and any method may be used as long as it oxidizes the substrate.

The second electrode may be a metal with a low work function, but is not limited thereto. Specifically, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead, or alloys thereof; It may be a multi-layered material such as LiF/Al, LiO ₂ /Al, LiF/Fe, Al:Li, Al:BaF ₂ , Al:BaF ₂ :Ba, but is not limited thereto.

The second electrode may be formed by depositing inside a thermal evaporator with a vacuum of 5x10 ^{- 7} torr or less, but the method is not limited to this method.

The hole transport layer and/or electron transport layer material serves to efficiently transfer electrons and holes separated from the photoactive layer to the electrode, and the material is not particularly limited.

The hole transport layer includes hole transport materials such as PEDOT:PSS (Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonic acid)), molybdenum oxide (MoO _x ); vanadium oxide (V ₂ O ₅ ); Nickel oxide (NiO); and tungsten oxide (WO _x ), etc., but is not limited to these.

The electron transport layer may include electron-extracting metal oxides as an electron transport material, specifically a metal complex of 8-hydroxyquinoline; Complex containing Alq ₃ ; Metal complexes containing Liq; LIF; Ca; Titanium oxide (TiO _x ); zinc oxide (ZnO); and cesium carbonate (Cs ₂ CO ₃ ), but is not limited to these.

In one embodiment of the present specification, the photoactive layer is formed by dissolving a photoactive material such as an electron donor and/or an electron acceptor in an organic solvent, and then applying the solution to spin coating, dip coating, screen printing, spray coating, doctor blade, brush painting, etc. It can be formed by the following methods, but is not limited to these methods.

The method for producing the copolymer and the production of an organic solar cell containing the same will be described in detail in the following Preparation Examples and Examples. However, the following examples are for illustrating the present specification, and the scope of the present specification is not limited thereto.

Preparation Example 1. Preparation of Copolymer 1

Monomer A-1 (0.5eq), monomer B-1 (0.5eq) and monomer C-1 (1eq) were mixed with tetrakis(triphenylphosphine)palladium(0)(Pd(PPh ₃ ) ₄ )(0.02eq). and toluene was injected at a rate of 10 mL per 1 mmol of monomer C-1 under nitrogen conditions. After stirring at 110°C for 16 hours, the reaction was terminated using methanol, and then purified with methanol, acetone, and hexane to prepare Copolymer 1.

At this time, it was confirmed that Copolymer 1 was produced by measuring the number average molecular weight (Mn). (Mn=31,164g/mol, PDI=1.80)

Figure 2 is a diagram showing the UV measurement results of Copolymer 1.

Specifically, in Figure 2, (a) shows the UV measurement results in a film state, and (b) shows the UV measurement results in a solution state.

UV measurements were performed at room temperature using Agilent's Cary UV-vis-NIR spectrometer equipment.

The film state was prepared by preparing a chlorobenzene solution containing 1 wt% of Copolymer 1, passing it through a 0.45㎛ PTFE syringe filter, and spin coating at 1,200 rpm on a glass substrate.

The solution state was measured in a quartz cell by preparing a chlorobenzene solution containing 0.001 wt% of Copolymer 1.

Preparation Example 2. Preparation of Copolymer 2

Copolymer 2 was prepared in the same manner as Preparation Example 1, except that monomer B-2 was used instead of monomer B-1 and monomer C-2 was used instead of monomer C-1.

At this time, it was confirmed that Copolymer 2 was produced by measuring the number average molecular weight (Mn). (Mn=13,694g/mol, PDI=1.39)

Figure 3 is a diagram showing the UV measurement results of Copolymer 2.

Specifically, in Figure 3, (a) shows the UV measurement results in a film state, and (b) shows the UV measurement results in a solution state.

UV measurements were performed at room temperature using Agilent's Cary UV-vis-NIR spectrometer equipment.

The film state was prepared by preparing a chlorobenzene solution containing 1 wt% of copolymer 2, passing it through a 0.45㎛ PTFE syringe filter, and spin coating at 1,200 rpm on a glass substrate.

The solution state was measured in a quartz cell by preparing a chlorobenzene solution containing 0.001 wt% of copolymer 2.

Preparation Example 3. Preparation of Copolymer 3

Copolymer 3 was prepared in the same manner as Preparation Example 1, except that monomer B-3 was used instead of monomer B-1 and monomer C-3 was used instead of monomer C-1.

At this time, it was confirmed that copolymer 3 was produced by measuring the number average molecular weight (Mn). (Mn=5,007g/mol, PDI=1.64)

Figure 4 is a diagram showing the UV measurement results of Copolymer 3.

Specifically, in Figure 4, (a) shows the UV measurement results in a film state, and (b) shows the UV measurement results in a solution state.

UV measurements were performed at room temperature using Agilent's Cary UV-vis-NIR spectrometer equipment.

The film state was prepared by preparing a chlorobenzene solution containing 1 wt% of Copolymer 3, passing it through a 0.45㎛ PTFE syringe filter, and spin coating at 1,200 rpm on a glass substrate.

The solution state was measured in a quartz cell by preparing a chlorobenzene solution containing 0.001 wt% of Copolymer 3.

Preparation Example 4. Preparation of Copolymer 4

Copolymer 4 was prepared in the same manner as Preparation Example 1, except that monomer B-2 was used instead of monomer B-1.

At this time, it was confirmed that copolymer 4 was produced by measuring the number average molecular weight (Mn). (Mn=30,426g/mol, PDI=1.76)

Figure 5 is a diagram showing the UV measurement results of Copolymer 4.

Specifically, in Figure 5, (a) shows the UV measurement results in a film state, and (b) shows the UV measurement results in a solution state.

UV measurements were performed at room temperature using Agilent's Cary UV-vis-NIR spectrometer equipment.

The film state was prepared by preparing a chlorobenzene solution containing 1 wt% of copolymer 4, passing it through a 0.45㎛ PTFE syringe filter, and spin coating at 1,200 rpm on a glass substrate.

The solution state was measured in a quartz cell by preparing a chlorobenzene solution containing 0.001 wt% of copolymer 4.

Preparation Example 5. Preparation of Copolymer 5

Copolymer 5 was prepared in the same manner as Preparation Example 1, except that monomer B-3 was used instead of monomer B-1.

At this time, it was confirmed that Copolymer 5 was produced by measuring the number average molecular weight (Mn). (Mn=32,525g/mol, PDI=1.73)

Figure 6 is a diagram showing the UV measurement results of Copolymer 5.

Specifically, in Figure 6, (a) shows the UV measurement results in a film state, and (b) shows the UV measurement results in a solution state.

UV measurements were performed at room temperature using Agilent's Cary UV-vis-NIR spectrometer equipment.

The film state was prepared by preparing a chlorobenzene solution containing 1 wt% of copolymer 5, passing it through a 0.45㎛ PTFE syringe filter, and spin coating at 1,200 rpm on a glass substrate.

The solution state was measured in a quartz cell by preparing a chlorobenzene solution containing 0.001 wt% of copolymer 5.

Preparation Example 6. Preparation of copolymer 6

Copolymer 6 was prepared in the same manner as Preparation Example 1, except that monomer B-4 was used instead of monomer B-1.

At this time, it was confirmed that copolymer 6 was produced by measuring the number average molecular weight (Mn). (Mn=34,350g/mol, PDI=1.63)

Figure 7 is a diagram showing the UV measurement results of Copolymer 6.

Specifically, in Figure 7, (a) shows the UV measurement results in a film state, and (b) shows the UV measurement results in a solution state.

UV measurements were performed at room temperature using Agilent's Cary UV-vis-NIR spectrometer equipment.

The film state was prepared by preparing a chlorobenzene solution containing 1 wt% of copolymer 6, passing it through a 0.45㎛ PTFE syringe filter, and spin coating at 1,200 rpm on a glass substrate.

The solution state was measured in a quartz cell by preparing a chlorobenzene solution containing 0.001 wt% of Copolymer 6.

Table 1 summarizes the UV measurement results of copolymers 1 to 6.

Solution
λ _max (nm) Film
λ _max (nm) Film λ _onset (nm) Optical E _g (eV) copolymer 1 585 590 641 1.93 copolymer 2 557 616 677 1.83 copolymer 3 533 583 696 1.78 copolymer 4 582 589 635 1.95 copolymer 5 583 588 634 1.96 copolymer 6 575 580 637 1.95

In Table 1, Solution λ _max refers to the maximum absorption wavelength of the copolymer in the solution state, Film λ _max refers to the maximum absorption wavelength of the copolymer in the film state, and Film λ _onset refers to the absorption onset point in the film state. means, and Optical E _g means the HOMO and LUMO energy band gaps of the copolymer calculated based on Film λ _onset .

Example 1. Preparation of organic solar cells

Copolymer 1 was used as an electron donor, and ITIC of the following structure was used as an electron acceptor, and was dissolved in chlorobenzene (CB) at a 1:1 mass ratio to prepare a composite solution. At this time, the concentration was adjusted to 2.0 wt%, and the organic solar cell had the structure of ITO/ZnO/photoactive layer/MoO ₃ /Ag. The ITO-coated glass substrate was ultrasonically cleaned using distilled water, acetone, and 2-propanol, and the ITO surface was treated with ozone for 10 minutes, followed by spin coating with a ZnO precursor solution and heat treatment at 120°C for 10 minutes. Afterwards, the composite solution was filtered through a 0.45μm PTFE syringe filter and then spin-coated to form a photoactive layer. Afterwards, MoO ₃ was deposited on the photoactive layer to a thickness of 5 nm to 20 nm in a thermal evaporator to prepare a hole transport layer. Afterwards, Ag was deposited to a thickness of 10 nm on the hole transport layer inside a thermal evaporator to manufacture an organic solar cell.

Example 2.

An organic solar cell was manufactured in the same manner as Example 1, except that Copolymer 4 was used instead of Copolymer 1 in Example 1.

Example 3.

An organic solar cell was manufactured in the same manner as Example 1, except that Copolymer 5 was used instead of Copolymer 1 in Example 1.

Example 4.

An organic solar cell was manufactured in the same manner as Example 1, except that Copolymer 6 was used instead of Copolymer 1 in Example 1.

Comparative Example 1.

An organic solar cell was manufactured in the same manner as Example 1, except that Copolymer J of the following structure was used instead of Copolymer 1 in Example 1.

The photoelectric conversion characteristics of the organic solar cells prepared in Examples 1 to 5 were measured under 100 mW/cm ² (AM 1.5) conditions, and the results are shown in Table 2.

V _oc
(V) J _sc
(mA/ ^cm2 ) FF η
(%) Example 1 0.896 15.981 63.23 9.054 Example 2 0.882 13.842 65.25 7.964 Example 3 0.930 14.112 57.86 7.594 Example 4 0.858 13.404 62.36 7.175 Comparative Example 1 0.930 11.941 51.96 5.770

In Table 2, Voc means open circuit voltage, Jsc means short circuit current, FF means fill factor, and η means energy conversion efficiency. The open-circuit voltage and short-circuit current are the X- and Y-axis intercepts in the fourth quadrant of the voltage-current density curve, respectively, and the higher these two values, the higher the efficiency of the solar cell. Additionally, the fill factor is the area of the rectangle that can be drawn inside the curve divided by the product of the short-circuit current and the open-circuit voltage. By dividing these three values by the intensity of irradiated light, energy conversion efficiency can be obtained, and higher values are more desirable.

From Table 2, it can be seen that the organic solar cells (Examples 1 to 4) according to an exemplary embodiment of the present specification have superior performance compared to Comparative Example 1.

10: substrate
20: first electrode
30: Electron transport layer
40: Photoactive layer
50: hole transport layer
60: second electrode

Claims (11)

A copolymer comprising a structure represented by the following formula 3-1:
[Formula 3-1]

In Formula 3-1,
f is the mole fraction, which is a real number 0<f<1,
g is the mole fraction, which is a real number 0<g<1,
f+g=1,
n is an integer from 1 to 10,000,
X1 to X4 are each S,
R3 and R4 are the same or different from each other and are each independently an alkoxy group; or a heterocyclic group substituted or unsubstituted with one or more substituents selected from the group consisting of a halogen group, an alkyl group, and an alkylthio group, provided that when R3 and R4 are substituted heterocyclic groups, R3 and R4 are not substituted with a silyl group.
R10 to R15 are each an alkyl group,
E1 and E2 are any one or a combination of two or more of the following structures,

X10 to X12 and X19 are each S or NR _d ,
R _d is an alkyl group,
R20 to R27, R30 and R31 are the same or different from each other and are each independently hydrogen; heavy hydrogen; halogen group; Alkyl group; Or it is an aryl group substituted or unsubstituted with an alkoxy group. delete delete delete delete delete delete In claim 1,
The copolymer is a copolymer comprising any one of the following structures:

first electrode;
a second electrode provided opposite the first electrode; and
It is provided between the first electrode and the second electrode, and includes one or more organic layers including a photoactive layer,
An organic solar cell wherein at least one of the organic layers includes the copolymer according to claim 1 or 8. In claim 9,
The photoactive layer includes an electron donor and an electron acceptor,
An organic solar cell wherein the electron donor includes the copolymer. In claim 9,
The organic solar cell further includes one or two or more organic material layers selected from the group consisting of a hole injection layer, a hole transport layer, a hole blocking layer, a charge generation layer, an electron blocking layer, an electron injection layer, and an electron transport layer. .