KR102074550B1 - Copolymer and organic solar cell comprising the same - Google Patents

Abstract

The present specification provides a copolymer and an organic solar cell including the same.

Description

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

The present specification relates to a copolymer and an organic solar cell including 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 according to the material constituting the thin film. Typical solar cells are made of p-n junctions by doping crystalline silicon (Si), an inorganic semiconductor. Electrons and holes generated 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 external circuits and the solar power entered into the solar cell, and is currently achieved by 24% when measured under standardized virtual solar irradiation conditions. However, since the conventional inorganic solar cell has already shown a limit in the economic and material supply and demand, the organic semiconductor solar cell is easy to process, inexpensive and versatile, has been spotlighted as a long-term alternative energy source.

It is important to increase efficiency so that solar cells can output as much electrical energy as possible from solar energy. It is important to generate as much excitons as possible inside the semiconductor to increase the efficiency of such solar cells, but it is also important to draw the generated charges to the outside without loss. One of the reasons for the loss of charge is that the generated electrons and holes disappear by recombination. Various methods have been proposed as methods for transferring the generated electrons or holes to the electrodes without loss, but most of the additional processes are required, and thus manufacturing costs may increase.

Two-layer organic photovoltaic cell (C.W.Tang, Appl. Phys. Lett., 48, 183. (1996)) Efficiencies via Network of Internal Donor-Acceptor Heterojunctions (G. Yu, J. Gao, J. C. Hummelen, F. Wudl, A. J. Heeger, Science, 270, 1789. (1995))

An object of the present specification is to provide a copolymer and an organic solar cell including the same.

The present specification provides a copolymer including a unit represented by the following Chemical Formula 1.

[Formula 1]

In Chemical Formula 1,

X1 to X5 are the same as or different from each other, and each independently CRR ', NR, O, SiRR', PR, S, GeRR ', Se or Te,

R, R 'and R1 to R6 are the same as or different from each other, and each independently hydrogen; heavy hydrogen; Halogen group; Nitrile group; Nitro group; Hydroxyl group; Carbonyl group; Ester group; Imide group; Amide group; Substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryloxy group; Substituted or unsubstituted alkyl thioxy group; Substituted or unsubstituted arylthioxy group; Substituted or unsubstituted alkyl sulfoxy group; Substituted or unsubstituted aryl sulfoxy group; Substituted or unsubstituted alkenyl group; Substituted or unsubstituted silyl group; Substituted or unsubstituted boron group; Substituted or unsubstituted amine group; Substituted or unsubstituted aryl phosphine group; Substituted or unsubstituted phosphine oxide group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

m is an integer from 3 to 10,

When m is 3 or more, the structures in parentheses are the same as or different from each other,

a is the mole fraction, where 0 <a <1,

b is the mole fraction, where 0 <b <1,

a + b = 1,

n is an integer of 1 to 1,000.

In addition, the present specification is a first electrode;

A second electrode provided to face the first electrode; And

At least one organic material layer provided between the first electrode and the second electrode, including a photoactive layer,

One or more layers of the organic material layer provides an organic solar cell including the copolymer.

The copolymer of the present specification may be used as a material of the organic solar cell organic material layer, and the organic solar cell including the same may exhibit excellent characteristics such as increase in open voltage and short circuit current and / or increase in efficiency.

Copolymers according to one embodiment of the present specification may exhibit excellent properties by having a deep HOMO level, a small band gap, and high charge mobility.

The copolymer according to an exemplary embodiment of the present specification may be used alone or in a mixture with other materials in an organic solar cell, and may improve efficiency and improve lifetime characteristics of the device by thermal stability of the compound.

1 is a view showing an organic solar cell according to an exemplary embodiment of the present specification.
2 is a diagram showing UV data of copolymer 1. FIG.
3 is a diagram showing CV data of copolymer 1. FIG.
4 is a diagram showing UV data of copolymer 3. FIG.
5 is a diagram showing CV data of copolymer 3. FIG.
6 is a diagram showing UV data of copolymer 5. FIG.
7 is a view showing the current density according to the voltage of the organic solar cell manufactured in the embodiment of the present specification.

Hereinafter, the present specification will be described in detail.

An exemplary embodiment of the present specification provides a copolymer including a unit of Chemical Formula 1.

The copolymer according to one embodiment of the present specification is a random copolymer. In the case of the random copolymer, the crystallinity is reduced, the degree of amorphousness is increased, long-term stability to heat can be ensured, and the manufacturing process of devices and modules including the copolymer is easy.

In addition, since the solubility can be easily adjusted by adjusting the ratio between the copolymers in the random copolymer, it is easy to provide solubility suitable for the manufacturing process of the organic solar cell, and thus a highly efficient organic solar cell can be manufactured.

In one embodiment of the present specification, the copolymer has a deep HOOC (Highest occupied molecular orbital) energy level and has a high charge mobility and is suitable as an electron donor material of an organic solar cell.

In addition, the copolymer according to one embodiment of the present specification may have the effect of reducing the band gap and / or increasing the amount of light absorption.

Copolymers according to one embodiment of the present specification increased the planarity of the molecules. In this case, the intermolecular interactions are increased and the stacking is well performed, so that the efficiency of the organic solar cell can be increased.

In addition, the copolymer according to one embodiment of the present specification has a high solubility and at the same time has a suitable solubility, there is an economical advantage in time and / or cost in the manufacture of the device.

In the present specification, when a part "includes" a certain component, this means that it may further include other components, without excluding other components, unless specifically stated otherwise.

In 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.

In the present specification, 'unit' is a repeating structure included in the monomer of the copolymer, and means a structure in which the monomer is bonded in the copolymer by polymerization.

In the present specification, the term "including units" means being included in the main chain in the polymer.

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

는 다른 치환기 또는 결합부에 결합되는 부위를 의미한다.In the present specification,

Means a site bonded to another substituent or binding moiety.

The term "substituted" means that a hydrogen atom bonded to a carbon atom of the compound is replaced with another substituent, and the position to be substituted is not limited to a position where the hydrogen atom is substituted, that is, a position where a substituent can be substituted, if two or more substituted , Two or more substituents may be the same or different from each other.

As used herein, the term "substituted or unsubstituted" is deuterium; Halogen group; Nitrile group; Nitro group; Hydroxyl group; Carbonyl group; Ester group; Imide group; Amine groups; Phosphine oxide groups; An alkoxy group; Aryloxy group; Alkyl thioxy group; Arylthioxy group; Alkyl sulfoxy groups; Aryl sulfoxy group; Substituted or unsubstituted silyl group; Boron group; Alkyl groups; Cycloalkyl group; Alkenyl groups; Aryl group; Aralkyl group; Ar alkenyl group; Alkylaryl group; Alkylamine group; Aralkyl amine groups; Heteroarylamine group; Arylamine group; Aryl phosphine group; And it is substituted or unsubstituted with one or more substituents selected from the group consisting of a heterocyclic group, or two or more substituents of the substituents exemplified above are substituted or unsubstituted. For example, "a substituent to which two or more substituents are linked" may be a biphenyl group. That is, the biphenyl group may be an aryl group or may be interpreted as a substituent to which two phenyl groups are linked.

Although carbon number of a carbonyl group in this specification is not specifically limited, It is preferable that it is C1-C40. Specifically, it may be a compound having a structure as follows, but is not limited thereto.

In the present specification, the ester group may be substituted with oxygen of the ester group having 1 to 25 carbon atoms, a straight chain, branched chain or cyclic alkyl group or an aryl group having 6 to 25 carbon atoms. Specifically, it may be a compound of the following structural formula, but is not limited thereto.

In the present specification, the amide group may be substituted with nitrogen of the amide group is hydrogen, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. Specifically, it may be a compound of the following structural formula, but is not limited thereto.

In this specification, although carbon number of an imide group is not specifically limited, It is preferable that it is C1-C25. Specifically, it may be a compound having a structure as follows, but is not limited thereto.

In the present specification, the silyl group may be represented by the formula of -SiR _a R _b R _c , wherein R _a , R _b and R _c are each hydrogen; Substituted or unsubstituted alkyl group; Or a substituted or unsubstituted aryl group. Specific examples of the silyl group include trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group, and phenylsilyl group, but are not limited thereto. Do not.

In the present specification, the boron group may be represented by a chemical formula of -BR _a R _b , wherein R _a and R _b are each hydrogen; Substituted or unsubstituted alkyl group; Or a substituted or unsubstituted aryl group. The boron group may include, but is not limited to, a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, and a phenylboron group.

In the present specification, examples of the halogen group include fluorine, chlorine, bromine or iodine.

In the present specification, the alkyl group may be linear or branched chain, carbon number is not particularly limited, but is preferably 1 to 40. According to an exemplary embodiment, the alkyl group has 1 to 20 carbon atoms. According to another exemplary embodiment, the alkyl group has 1 to 10 carbon atoms. According to another exemplary embodiment, the alkyl group has 1 to 6 carbon atoms. Specific examples of the alkyl group 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, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2 -Dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, 5-methylhexyl, and the like, but is not limited thereto.

In the present specification, the alkenyl group may be linear or branched chain, carbon number is not particularly limited, but is preferably 2 to 40. According to an exemplary embodiment, the alkenyl group has 2 to 20 carbon atoms. According to another exemplary embodiment, the alkenyl group has 2 to 10 carbon atoms. According to another exemplary embodiment, the alkenyl group has 2 to 6 carbon atoms. 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 and the like, but are not limited thereto.

In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms, and according to one embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another exemplary embodiment, the cycloalkyl group has 3 to 20 carbon atoms. According to another exemplary embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specifically cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3, 4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, and the like, but is not limited thereto.

In the present specification, the alkoxy group is not particularly limited, but is preferably 1 to 40 carbon atoms. According to an exemplary embodiment, the alkoxy group has 1 to 10 carbon atoms. According to another exemplary embodiment, the alkoxy group has 1 to 6 carbon atoms. Specific examples of the alkoxy group include, but are not limited to, methoxy group, ethoxy group, propoxy group, isobutyloxy group, sec-butyloxy group, pentyloxy group, iso-amyloxy group, hexyloxy group, and the like.

In the present specification, the amine group is an alkylamine group; Aralkyl amine groups; Heteroarylamine group; And arylamine groups.

In the present specification, the amine group is not particularly limited, but is preferably 1 to 30. Specific examples of the amine group include methylamine group, dimethylamine group, ethylamine group, diethylamine group, phenylamine group, naphthylamine group, biphenylamine group, anthracenylamine group, and 9-methyl-anthracenylamine group. , Diphenylamine group, phenylnaphthylamine group, ditolylamine group, phenyltolylamine group, triphenylamine group and the like, but are not limited thereto.

In the present specification, examples of the arylamine group include a substituted or unsubstituted monoarylamine group, a substituted or unsubstituted diarylamine group, or a substituted or unsubstituted triarylamine group. The aryl group in the arylamine group may be a monocyclic aryl group, may be a polycyclic aryl group. The arylamine group including two or more aryl groups may simultaneously include a monocyclic aryl group, a polycyclic aryl group, or a monocyclic aryl group and a polycyclic aryl group.

Specific examples of the arylamine group include phenylamine, naphthylamine, biphenylamine, anthracenylamine, 3-methyl-phenylamine, 4-methyl-naphthylamine, 2-methyl-biphenylamine, 9-methyl-anthra Cenylamine, diphenyl amine group, phenyl naphthyl amine group, ditolyl amine group, phenyl tolyl amine group, carbazole and triphenyl amine group and the like, but are not limited thereto.

In the present specification, examples of the arylphosphine group include a substituted or unsubstituted monoarylphosphine group, a substituted or unsubstituted diarylphosphine group, or a substituted or unsubstituted triarylphosphine group. The aryl group in the arylphosphine group may be a monocyclic aryl group, may be a polycyclic aryl group. The arylphosphine group containing two or more aryl groups may include a monocyclic aryl group, a polycyclic aryl group, or a monocyclic aryl group and a polycyclic aryl group at the same time.

In the present specification, the aryl group is not particularly limited, but preferably has 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to an exemplary embodiment, the aryl group has 6 to 30 carbon atoms. According to an exemplary embodiment, the aryl group has 6 to 20 carbon atoms. The aryl group may be a phenyl group, a biphenyl group, a terphenyl group, etc. as the monocyclic aryl group, but is not limited thereto. The polycyclic aryl group may be naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, peryleneyl group, chrysenyl group, fluorenyl group, triphenylene group, etc., but is not limited thereto.

In the present specification, a fluorenyl group may be substituted, and two substituents may be bonded to each other to form a spiro structure.

,

,

,

,

,

,

및

등이 될 수 있다. 다만, 이에 한정되는 것은 아니다.When the fluorenyl group is substituted,

,

,

,

,

,

,

And

And so on. However, the present invention is not limited thereto.

In the present specification, the heterocyclic group is a heterocyclic group containing at least one of N, O, S, Si, and Se as hetero atoms, and the carbon number is not particularly limited, but is preferably 2 to 60 carbon atoms. Examples of the heterocyclic group include thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, triazole group, Acridil group, pyridazine group, pyrazinyl group, quinolinyl group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidinyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group, isoquinoline group , Indole group, carbazole group, benzoxazole group, benzimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, phenanthroline group, thiazolyl group, Isoxazolyl group, oxdiazolyl group, thiadiazolyl group, benzothiazolyl group, phenoxazinyl group, phenothiazinyl group and dibenzofuranyl group, and the like, but are not limited thereto. The heterocyclic group may be monocyclic or polycyclic, and include an aliphatic heterocyclic group and an aromatic heterocyclic group.

In the present specification, examples of the heteroarylamine group include a substituted or unsubstituted monoheteroarylamine group, a substituted or unsubstituted diheteroarylamine group, or a substituted or unsubstituted triheteroarylamine group. The heteroarylamine group including two or more heteroaryl groups may include a monocyclic heteroaryl group, a polycyclic heteroaryl group, or a monocyclic heteroaryl group and a polycyclic heteroaryl group at the same time. For example, the heteroaryl group in the heteroarylamine group may be selected from the examples of the heteroaryl group described above.

In the present specification, examples of the heteroaryl group in the N-arylheteroarylamine group and the N-alkylheteroarylamine group are the same as the examples of the heteroaryl group described above.

In the present specification, the aryl group in the aryloxy group, arylthioxy group, aryl sulfoxy group, aryl phosphine group, aralkyl group, aralkylamine group, aralkenyl group, alkylaryl group, arylamine group, arylheteroarylamine group is described above. The description of one aryl group may apply.

In the present specification, the alkyl group of the alkyl thioxy group, the alkyl sulfoxy group, the aralkyl group, the aralkylamine group, the alkylaryl group, the alkylamine group, the description of the above-described alkyl group may be applied.

In the present specification, the heteroaryl group, the heteroarylamine group, and the arylheteroarylamine group, except that the heteroaryl group is aromatic, the description of the heterocyclic group may be applied.

In the present specification, R1 to R6 are the same as or different from each other, and each independently hydrogen; Substituted or unsubstituted alkyl group; Substituted or unsubstituted alkoxy group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group.

In the present specification, the R1 to R6 are the same as or different from each other, and each independently hydrogen; A substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms; Or a substituted or unsubstituted heterocyclic group having 2 to 60 carbon atoms.

In the present specification, R1 and R2 are substituted or unsubstituted heterocyclic groups, respectively.

In the present specification, R1 and R2 are substituted or unsubstituted thiophene groups, respectively.

In the present specification, R1 and R2 are thiophene groups each substituted with an alkyl group.

In the present specification, R1 and R2 are substituted or unsubstituted carbazole groups, respectively.

In the present specification, R1 and R2 are carbazole groups each substituted with an alkyl group.

In the present specification, R3 and R6 are each a substituted or unsubstituted alkyl group.

In the present specification, R3 and R6 are each a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms.

In the present specification, R3 and R6 are each an unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms.

In the present specification, R4 and R5 are each hydrogen.

In the present specification, R4 and R5 are each a substituted or unsubstituted alkyl group.

In the present specification, R4 and R5 are substituted or unsubstituted linear or branched alkyl groups having 1 to 20 carbon atoms, respectively.

In the present specification, R4 and R5 are each an unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms.

In the present specification, X1 is S.

In the present specification, X2 is S.

In the present specification, X3 is S.

In the present specification, X4 is S.

In the present specification, X5 is S.

In the present specification, X6 is S.

In one embodiment of the present specification, the copolymer is a copolymer represented by any one of the following Formulas 1-1 to 1-5.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

In Chemical Formulas 1-1 to 1-5, the definitions of a, b, and n are the same as defined in Chemical Formula 1.

In one embodiment of the present specification, a and b are each 0.5.

In the present specification, the end group of the copolymer is a heterocyclic group or an aryl group.

According to one embodiment of the present specification, the copolymer has a number average molecular weight of 500 g / mol to 2,000,000 g / mol. Preferably, the number average molecular weight of the copolymer is preferably 10,000g / mol to 100,000g / mol. In one embodiment of the present specification, the copolymer has a number average molecular weight of 30,000 g / mol to 70,000 g / mol.

According to an exemplary embodiment of the present specification, the copolymer may have a molecular weight distribution of 1 to 100. Preferably the copolymer has a molecular weight distribution of 1 to 3.

In the present specification, the molecular weight distribution means a polydispersity index (PDI).

The lower the molecular weight distribution, the higher the number average molecular weight, the better the electrical and mechanical properties.

In addition, the number average molecular weight is preferably 200,000 g / mol or less in order to have a solubility or higher so that the solution coating method is advantageous.

In one embodiment of the present specification, the first electrode;

A second electrode provided to face the first electrode; And

It includes at least one organic material layer provided between the first electrode and the second electrode, including a photoactive layer,

One or more layers of the organic material layer provides an organic solar cell including the copolymer.

The organic solar cell according to the exemplary embodiment of the present specification 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, when the organic solar cell receives photons from an external light source, electrons and holes are generated between the electron donor and the electron acceptor. The generated holes are transported to the anode through the electron donor layer.

In one embodiment of the present specification, the organic material layer includes a hole transport layer, a hole injection layer, or a layer for simultaneously transporting holes and holes, and simultaneously transporting the hole transport layer, the hole injection layer, or the hole transport and the hole injection. The layer comprises the copolymer.

In another exemplary embodiment, the organic material layer includes an electron injection layer, an electron transport layer, or a layer for simultaneously performing electron injection and electron transport, and the electron injection layer, an electron transport layer, or a layer for simultaneously performing electron injection and electron transport, It includes the copolymer.

In one embodiment of the present specification, when the organic solar cell receives photons from an external light source, electrons and holes are generated between the electron donor and the electron acceptor. The generated holes are transported to the anode through the electron donor layer.

In one embodiment of the present specification, the organic solar cell is one 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 generating layer, an electron blocking layer, an electron injection layer and an electron transport layer. It may further include.

In one embodiment of the present specification, the organic solar cell may further include an additional organic material layer. The organic solar cell may reduce the number of organic material layers by using an organic material having several functions at the same time.

In one embodiment of the present specification, the organic solar cell may be arranged in the order of cathode, photoactive layer and anode, and may be arranged in order of anode, photoactive layer and cathode, but is not limited thereto.

In another exemplary embodiment, the organic solar cell may be arranged in order of an anode, a hole transport layer, a photoactive layer, an electron transport layer, and a cathode, or may be arranged in the order of a cathode, an electron transport layer, a photoactive layer, a hole transport layer, and an anode. It is not limited to this.

In another exemplary embodiment, a buffer layer may be provided between the photoactive layer and the hole transport layer or between the photoactive layer and the electron transport layer. In this case, a hole injection layer may be further provided between the anode and the hole transport layer. In addition, an electron injection layer may be further provided between the cathode and the electron transport layer.

In one embodiment of the present specification, the photoactive layer includes one or two or more selected from the group consisting of an electron donor and an acceptor, and the electron donor includes the copolymer.

In one embodiment of the present specification, the electron acceptor material may be selected from the group consisting of fullerenes, fullerene derivatives, vasocuprones, semiconducting elements, semiconducting compounds, and combinations thereof. Specifically, it may be 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 the electron acceptor constitute a bulk hetero junction (BHJ). The electron donor material and the electron acceptor material may be mixed in a ratio (w / w) of 1:10 to 10: 1. Specifically, the electron donor material and the electron acceptor material may be mixed in a ratio (w / w) of 1: 1 to 1:10, and more specifically, the electron donor material and the electron acceptor material are 1: 1 to 1: 5. Can be mixed at a ratio (w / w). If necessary, the electron donor material and the electron acceptor material may be mixed in a ratio (w / w) of 1: 1 to 1: 3.

In one embodiment of the present specification, the photoactive layer has a bilayer bilayer structure including an n-type organic compound layer and a p-type organic compound layer, and the p-type organic compound layer includes the copolymer.

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

The anode electrode may be a transparent and excellent conductive material, but is not limited thereto. Metals such as vanadium, chromium, copper, zinc and gold or alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO); ZnO: Al or SNO ₂ : Combination of metals and oxides such as Sb; Conductive polymers such as poly (3-methylthiophene), poly [3,4- (ethylene-1,2-dioxy) thiophene] (PEDOT), polypyrrole and polyaniline, and the like, but are not limited thereto.

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

When the anode electrode is formed on a substrate, it may be subjected to cleaning, water removal, and hydrophilic modification.

For example, the patterned ITO substrate is sequentially cleaned with a detergent, acetone, and isopropyl alcohol (IPA), and then dried in a heating plate for 1 to 30 minutes at 100 ° C. to 150 ° C., preferably at 120 ° C. for 10 minutes to remove moisture. When the substrate is thoroughly cleaned, the surface of the substrate is modified to be hydrophilic.

Through such surface modification, the bonding surface potential can be maintained at a level suitable for the surface potential of the photoactive layer. In addition, it is easy to form a polymer thin film on the anode electrode during modification, the quality of the thin film may be improved.

Pretreatment techniques for the anode electrode include a) surface oxidation using parallel plate discharge, b) oxidation of the surface with ozone generated using UV ultraviolet light in a vacuum state, and c) oxygen generated by plasma. And oxidation using radicals.

One of the above methods can be selected depending on the state of the anode electrode or the substrate. In any case, however, it is desirable to prevent oxygen escape from the surface of the anode electrode or the substrate and to minimize the residual of moisture and organic matter in common. At this time, the substantial effect of the pretreatment can be maximized.

As a specific example, a method of oxidizing a surface through ozone generated using UV may be used. At this time, after ultrasonic cleaning, the patterned ITO substrate is baked on a hot plate, dried well, then put into a chamber, and a UV lamp is activated to cause oxygen gas to react with UV light. The patterned ITO substrate can be cleaned.

However, the surface modification method of the patterned ITO substrate in this specification does not need to be specifically limited, Any method may be used as long as it is a method of oxidizing a substrate.

The cathode electrode may be a metal having a small 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; LiF / Al, LiO ₂ / Al, LiF / Fe, Al: Li, Al: BaF ₂ , Al: BaF ₂ It may be a material of a multi-layer structure such as, but is not limited thereto.

The cathode electrode is 5x10 ^- may be formed is deposited on the internal heat evaporator showing a degree of vacuum of less than ⁷ torr, not limited to this method.

The hole transport layer and / or the electron transport layer material plays a role of efficiently transferring electrons and holes separated in the photoactive layer to the electrode, and the material is not particularly limited.

The hole transport layer material may be PEDOT: PSS (Poly (3,4-ethylenediocythiophene) doped with poly (styrenesulfonic acid)), molybdenum oxide (MoO _x ); Vanadium oxide (V ₂ O ₅ ); Nickel oxide (NiO); Tungsten oxide (WO _x ), and the like, but is not limited thereto.

The electron transport layer material may be electron-extracting metal oxides, specifically, a metal complex of 8-hydroxyquinoline; Complexes including Alq ₃ ; Metal complexes including Liq; LiF; Ca; Titanium oxide (TiO _x ); Zinc oxide (ZnO); And cesium carbonate (Cs ₂ CO ₃ ), and the like, but is not limited thereto.

The photoactive layer may be formed by dissolving a photoactive material, such as an electron donor and / or an electron acceptor, in an organic solvent and then spin coating, dip coating, screen printing, spray coating, doctor blade, brush painting, or the like. It is not limited to the method.

The manufacturing method of the copolymer and the preparation of the organic solar cell including the same will be described in detail in the following Preparation Examples and Examples. However, the following examples are intended to illustrate the present specification, and the scope of the present specification is not limited thereto.

The manufacturing method of the copolymer and the preparation of the organic solar cell including the same will be described in detail in the following Examples. However, the following examples are intended to illustrate the present specification, and the scope of the present specification is not limited thereto.

Production Example  1. Synthesis of Copolymer 1

5 ml of chlorobenzene (CB), Compound A 0.35 mmol, Compound B 0.7 mmol, Compound C 0.35 mmol, Bis (dibenzylideneacetone) palladium (0) in a microwave reactor vial (Pd (dba) ) ₂ : (bis (dibenzylideneacetone) palladium (0), 12.8mg) and tri- (o-tolyl) phosphine (17mg) were added and reacted for 1 hour at 150 ° C. The mixture was cooled to room temperature, poured into methanol, and then filtered through a solid, followed by Soxhlet extraction with methanol, acetone, hexane and chloroform, and then the chloroform portion was precipitated in methanol again to filter out the solid.

2 is a diagram showing UV data of copolymer 1. FIG.

In Figure 2 (a) is the UV data in the film state of the copolymer 1, (b) is the UV data measuring the copolymer 1 in the solution state.

In this case, (a) is the UV data measured after dissolving copolymer 1 in chlorobenzene to produce a film by spin coating method, (b) is the UV data measured after dissolving copolymer 1 in chlorobenzene.

3 is a diagram showing CV data of copolymer 1. FIG.

Production Example  2. Synthesis of Copolymer 2

5 ml of chlorobenzene (CB), Compound A 0.35 mmol, Compound B 0.7 mmol, Compound D 0.35 mmol, Bis (dibenzylideneacetone) palladium (0) in a microwave reactor vial (Pd (dba) ) _{2 :} (bis (dibenzylideneacetone) palladium (0), 12.8mg) and tri- (o-tolyl) phosphine (17mg) were added and reacted for 1 hour at 150 ° C. The mixture was cooled to room temperature, poured into methanol, and then filtered through a solid, followed by Soxhlet extraction with methanol, acetone, hexane and chloroform, and then the chloroform portion was precipitated in methanol again to filter out the solid.

Production Example  3. Synthesis of Copolymer 3

5 ml of chlorobenzene (CB), Compound E 0.35 mmol, Compound B 0.7 mmol, Compound D 0.35 mmol, Bis (dibenzylideneacetone) palladium (0) in a microwave reactor vial (Pd (dba) _{) 2: (bis (dibenzylideneacetone)} palladium (0), 12.8mg), tri- (o-tolyl) phosphine (tri- (o-tolyl) phosphine, placed 17 mg) was reacted for 1 hour under conditions 150 ℃ The mixture was cooled to room temperature, poured into methanol, filtered and the solid was filtered through Soxhlet extraction in methanol, acetone, hexane and chloroform, and then the chloroform portion was precipitated in methanol again to filter out the solid.

4 is a diagram showing UV data of copolymer 3.

In Figure 4 (a) is the UV data in the film state of the copolymer 3, (b) is UV data measured for the copolymer 3 in the solution state.

In this case, (a) is the UV data measured after dissolving copolymer 3 in chlorobenzene to produce a film through a spin coating method, (b) is the UV data measured after dissolving copolymer 3 in chlorobenzene.

5 is a diagram showing CV data of copolymer 3. FIG.

Production Example  4. Synthesis of Copolymer 4

5 ml of chlorobenzene (CB), Compound A 0.35 mmol, Compound B 0.7 mmol, Compound F 0.35 mmol, Bis (dibenzylideneacetone) palladium (0) in a microwave reactor vial (Pd (dba) ) _{2 :} (bis (dibenzylideneacetone) palladium (0), 12.8mg) and tri- (o-tolyl) phosphine (17mg) were added and reacted for 1 hour at 150 ° C. The mixture was cooled to room temperature, poured into methanol, and then filtered through a solid, followed by Soxhlet extraction with methanol, acetone, hexane and chloroform, and then the chloroform portion was precipitated in methanol again to filter out the solid.

Production Example  5. Synthesis of Copolymer 5

5 ml of chlorobenzene (CB), Compound A 0.35 mmol, Compound B 0.7 mmol, Compound G 0.35 mmol, Bis (dibenzylideneacetone) palladium (0) in a microwave reactor vial (Pd (dba) ) _{2 :} (bis (dibenzylideneacetone) palladium (0), 12.8mg) and tri- (o-tolyl) phosphine (17mg) were added and reacted for 1 hour at 150 ° C. The mixture was cooled to room temperature, poured into methanol, and then filtered through a solid, followed by Soxhlet extraction with methanol, acetone, hexane and chloroform, and then the chloroform portion was precipitated in methanol again to filter out the solid.

6 is a diagram showing UV data of copolymer 5. FIG.

In Figure 6 (a) is the UV data in the film state of the copolymer 5, (b) is the UV data measured the copolymer 5 in the solution state.

At this time, (a) is the UV data measured after dissolving copolymer 5 in chlorobenzene to prepare a film by spin coating method, (b) is the UV data measured after dissolving copolymer 5 in chlorobenzene.

Fabrication and Characterization of Organic Solar Cells

Experimental Example  1. Fabrication of Organic Solar Cell-1

Copolymer 1 and PC ₆₁ BM prepared in Preparation Example 1 were dissolved in chlorobenzene (CB) in a ratio of 1: 2 to prepare a composite solution. At this time, the concentration was adjusted to 4.0 wt%, and the organic solar cell had a structure of ITO / PEDOT: PSS / photoactive layer / Al. ITO-coated glass substrates were ultrasonically cleaned with distilled water, acetone and 2-propanol, ozonated the ITO surface for 10 minutes, and spin-coated PEDOT: PSS (baytrom P) to 45 nm for 10 minutes at 120 ° C. Heat treatment for Thereafter, the copolymer 1-PC ₆₁ BM composite solution was filtered through a 0.45 μm PP syringe filter and then spin coated to form a photoactive layer. Thereafter, Al was deposited to a thickness of 200 nm using a thermal evaporator under a 3 × 10 ⁻⁸ torr vacuum to prepare an organic solar cell.

Experimental Example  2. Fabrication of Organic Solar Cell-2

An organic solar cell was manufactured by the same method as Experimental Example 1, except that copolymer 5 prepared in Preparation Example 5 was used instead of Copolymer 1 prepared in Preparation Example 1 in Experimental Example 1.

Comparative example  1. Fabrication of Organic Solar Cell-3

An organic solar cell was manufactured by the same method as Experimental Example 1, except that the following compound H-1 was used instead of the copolymer 1 prepared in Preparation Example 1 in Experimental Example 1.

Comparative example  2. Fabrication of Organic Solar Cell-4

An organic solar cell was manufactured by the same method as Experimental Example 1, except that the following compound H-2 was used instead of the copolymer 1 prepared in Preparation Example 1 in Experimental Example 1.

< Test Example >

The photoelectric conversion characteristics of the organic solar cells prepared in Experimental Examples 1 and 2 and Comparative Examples 1 to 3 were measured under 100 mW / cm ² (AM 1.5), and the results are shown in Table 1 below.

Active layer V _OC (V) J _SC (mA / cm ² ) FF (%) PCE (%) Experimental Example 1 Copolymer 1 / PC ₆₁ BM = 1: 2 0.88 11.42 0.72 7.22 Experimental Example 2 Copolymer 5 / PC ₆₁ BM = 1: 2 0.86 9.45 0.67 5.42 Comparative Example 1 Compound H-1 / PC ₆₁ BM = 1: 2 0.36 8.0 0.58 2.96 Comparative Example 2 Compound H-3 / PC ₆₁ BM = 1: 2 0.71 2.3 0.46 0.75

In Table 1, V _oc is the open voltage, J _sc is the short-circuit current, FF is the fill factor, and PCE is the energy conversion efficiency. The open-circuit and short-circuit currents are the X- and Y-axis intercepts in the four quadrants of the voltage-current density curves, respectively. Also, the fill factor is the area of the rectangle drawn inside the curve divided by the product of the short circuit current and the open voltage. By dividing these three values by the intensity of the light emitted, the energy conversion efficiency can be obtained, and higher values are preferable.

7 shows the current density according to the voltage of the organic solar cell manufactured in the embodiment of the present specification.

101: substrate
102: first electrode
103: hole transport layer
104: photoactive layer
105: second electrode

Claims (12)

A copolymer represented by any one of the following Formulas 1-1 to 1-3:
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

In Chemical Formulas 1-1 to 1-3,
a is the mole fraction, where 0 <a <1,
b is the mole fraction, where 0 <b <1,
a + b = 1,
n is an integer of 1 to 1,000. delete delete The method according to claim 1,
The copolymer has a number average molecular weight of 500 g / mol to 2,000,000 g / mol. The method according to claim 1,
The copolymer has a molecular weight distribution of 1 to 100. The method according to claim 1,
The copolymer is a random copolymer. A first electrode;
A second electrode provided to face the first electrode; And
At least one organic material layer provided between the first electrode and the second electrode, including a photoactive layer,
At least one layer of the organic material layer is an organic solar cell comprising a copolymer according to any one of claims 1 and 4 to 6. The method according to claim 7,
The organic material layer includes a hole transport layer, a hole injection layer or a layer for simultaneously performing hole transport and hole injection,
The hole transport layer, the hole injection layer or the layer for simultaneously hole transport and hole injection comprises an organic solar cell. The method according to claim 7,
The organic material layer includes an electron injection layer, an electron transport layer or a layer for simultaneously performing electron injection and electron transport,
The electron injection layer, the electron transport layer or the layer for simultaneously performing the electron injection and the electron transport comprises an organic solar cell. The method according to claim 7,
The photoactive layer includes an electron donor and an electron acceptor,
The electron donor is an organic solar cell comprising the copolymer. The method according to claim 10,
The electron donor and the electron acceptor constitute a bulk hetero junction (BHJ). The method according to claim 7,
The organic solar cell further comprises one 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 generating layer, an electron blocking layer, an electron injection layer and an electron transport layer. .

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