KR102176846B1 - Heterocyclic compound and organic solar cell comprising the same - Google Patents

Abstract

The present specification relates to a heterocyclic compound represented by Chemical Formula 1 and an organic solar cell including the same.

Description

Heterocyclic compound and organic solar cell including the same TECHNICAL FIELD

The present specification relates to a heterocyclic compound and an organic solar cell including the same.

An organic solar cell is a device that can directly convert solar energy into electric energy by applying a photovoltaic effect. Solar cells can be divided into inorganic solar cells and organic solar cells depending on the material constituting the thin film. A typical solar cell is made of a p-n junction by doping crystalline silicon (Si), an inorganic semiconductor. Electrons and holes generated by absorbing light diffuse to the p-n junction, accelerated by the electric field, and 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 entered into the solar cell, and was achieved up to 24% when measured under the currently standardized virtual solar irradiation conditions. However, since conventional inorganic solar cells already show limitations in economic and material supply and demand, organic semiconductor solar cells that are easy to process, inexpensive, and have various functions are in the spotlight as a long-term alternative energy source.

It is important to increase the efficiency of solar cells so that they can output as much electric energy as possible from solar energy. In order to increase the efficiency of such a solar cell, it is important to generate as many excitons as possible inside the semiconductor, but it is also important to draw the generated charges to the outside without loss. One of the causes of the loss of charge is that the generated electrons and holes are destroyed by recombination. Various methods have been proposed as methods for transferring generated electrons or holes to an electrode without loss, but most require an additional process, and thus manufacturing cost may increase.

US 5331183 US 5454880

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

The present specification provides a heterocyclic compound represented by the following formula (1).

[Formula 1]

In Formula 1,

m1, m2, n1 and n2 are each an integer of 1 to 3,

When m1, m2, n1 and n2 are each 2 or more, the structures in the two or more brackets are the same as or different from each other,

L2 and L3 are the same as or different from each other, and each independently a direct bond; Or a divalent linking group,

R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; heavy hydrogen; Halogen group; Nitrile group; Nitro group; Imide group; Amide group; Hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryloxy group; A substituted or unsubstituted alkyl thioxy group; A substituted or unsubstituted arylthioxy group; A substituted or unsubstituted alkyl sulfoxy group; Substituted or unsubstituted arylsulfoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted alkylamine group; A substituted or unsubstituted aralkylamine group; A substituted or unsubstituted arylamine group; A substituted or unsubstituted heteroarylamine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group containing one or more of N, O and S atoms,

G1 and G2 are the same as or different from each other, and each independently a substituted or unsubstituted branched alkyl group,

A1 and A2 are the same as or different from each other, and each independently has a structure that acts as an electron acceptor.

In addition, the present specification 1 electrode; A second electrode provided to face the first electrode; And one or more organic material layers provided between the first electrode and the second electrode and including a photoactive layer, and at least one of the organic material layers includes the aforementioned heterocyclic compound. do.

The heterocyclic compound according to an exemplary embodiment of the present specification has a core having a structure including two or more benzodithiophene (BDT) having electron donating properties, and thus has a long effective conjugation length.

In addition, since the heterocyclic compound according to an exemplary embodiment of the present specification has a core having a structure including two or more benzodithiophene (BDT), a compound having an increased molecular weight may be provided.

In addition, since the heterocyclic compound according to an exemplary embodiment of the present specification includes a branched alkoxy group in the benzothiadiazole connecting two benzodithiophenes (BDT), steric hindrance between molecules increases, so that the solubility of the compound can be controlled. have.

Accordingly, the heterocyclic compound may be used as an organic material layer material of an organic solar cell, and an organic solar cell including the same may exhibit excellent properties in terms of an increase in open circuit voltage and short-circuit current, a low band gap effect, and/or an increase in efficiency. .

The heterocyclic compound according to an exemplary embodiment of the present specification can be used alone or in combination with other materials in an organic solar cell, and it can be expected to improve the lifespan of the device due to characteristics such as improved efficiency and thermal stability of the compound. have.

1 is a diagram showing an organic solar cell according to an exemplary embodiment of the present specification.
2 is a diagram showing an NMR graph of compound 1-1.

Hereinafter, the present specification will be described in detail.

The present specification provides a heterocyclic compound represented by Chemical Formula 1.

는 다른 치환기에 연결되는 부위를 의미한다.In this specification,

Means a moiety connected to another substituent.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

Examples of the substituent are described below, but are not limited thereto.

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

In the present specification, the term "substituted or unsubstituted" refers to deuterium; Halogen group; Alkyl group; Alkenyl group; Alkoxy group; Ester group; Carbonyl group; Carboxyl group; Hydroxy group; Cycloalkyl group; Silyl group; Arylalkenyl group; Aryloxy group; Alkyl thioxy group; Alkyl sulfoxy group; Arylsulfoxy group; Boron group; Alkylamine group; Aralkylamine group; Arylamine group; Heterocyclic group; Arylamine group; Aryl group; Nitrile group; Nitro group; Hydroxy group; And one or more substituents selected from the group consisting of a heterocyclic group containing one or more of N, O, and S atoms, or not having any substituents.

The substituents may be substituted or unsubstituted with an additional substituent.

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

In the present specification, the number of carbon atoms of the imide group is not particularly limited, but it is preferably 1 to 25 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

In the present specification, the amide group may be substituted with 1 or 2 nitrogen in the amide group with hydrogen, a straight chain, branched or cyclic alkyl group having 1 to 25 carbon atoms, 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 alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 50. 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, cyclopentylmethyl, cycloheptylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethyl Heptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, and the like, but are not limited thereto.

In the present specification, the cycloalkyl group is not particularly limited, but is preferably 3 to 60 carbon atoms, and 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 and cyclooctyl, but are not limited thereto. Does not.

In the present specification, the alkoxy group may be linear, branched or cyclic. The number of carbon atoms of the alkoxy group is not particularly limited, but it is preferably 1 to 20 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 and p-methylbenzyloxy, etc. May be, but is not limited thereto.

In the present specification, the alkenyl group may be a linear or branched chain, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. 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, and styrenyl group, but are not limited thereto.

In the present specification, the silyl group is specifically trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group, phenylsilyl group, etc. However, it is not limited thereto.

In the present specification, the aryl group may be a monocyclic aryl group or a polycyclic aryl group, and includes a case where an alkyl group having 1 to 25 carbon atoms or an alkoxy group having 1 to 25 carbon atoms is substituted. In addition, the aryl group in the present specification may mean an aromatic ring.

When the aryl group is a monocyclic aryl group, the number of carbon atoms is not particularly limited, but it is preferably 6 to 25 carbon atoms. Specifically, the monocyclic aryl group may be a phenyl group, a biphenyl group, and a terphenyl group, but is not limited thereto.

When the aryl group is a polycyclic aryl group, the number of carbon atoms is not particularly limited. It is preferably 10 to 24 carbon atoms. Specifically, the polycyclic aryl group may be a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, and a fluorenyl group, but is not limited thereto.

In the present specification, the fluorenyl group is a structure in which two cyclic organic compounds are connected through one atom.

In the present specification, the fluorenyl group may be substituted, and adjacent substituents may be bonded to each other to form a ring.

,

,

및

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

,

,

And

Etc. However, it is not limited thereto.

In the present specification, the heteroaryl group is a heteroaryl group containing at least one of O, N, and S as a heterogeneous element, and the number of carbons is not particularly limited, but it is preferably 2 to 60 carbon atoms. Examples of heteroaryl groups include thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, triazole group, acridyl 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, benzoimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, thiazolyl group, isoxazolyl Group, oxadiazolyl group, thiadiazolyl group, benzothiadiazolyl group, benzothiazolyl group, phenothiazinyl group, dibenzofuranyl group, and the like, but are not limited thereto.

In the present specification, the heterocyclic group may be monocyclic or polycyclic, may be aromatic, aliphatic, or condensed rings of aromatic and aliphatic, and may be selected from examples of the heteroaryl group.

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 or a polycyclic aryl group. The arylamine 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.

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

In the present specification, the heteroaryl group of the heteroarylamine group may be selected from the examples of the aforementioned heterocyclic group.

In the present specification, the aryl group in the aryloxy group, arylthioxy group, arylsulfoxy group, and aralkylamine group is the same as the example of the aryl group described above. Specifically, the aryloxy group includes phenoxy, p-tolyloxy, m-tolyloxy, 3,5-dimethyl-phenoxy, 2,4,6-trimethylphenoxy, p-tert-butylphenoxy, 3-biphenyl Oxy, 4-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 4-methyl-1-naphthyloxy, 5-methyl-2-naphthyloxy, 1-anthryloxy, 2-anthryl Oxy, 9-anthryloxy, 1-phenanthryloxy, 3-phenanthryloxy, and 9-phenanthryloxy, and the arylthioxy group includes a phenylthioxy group, a 2-methylphenylthioxy group, and a 4-tert-butylphenyl There are thioxy groups, and the aryl sulfoxy group includes a benzene sulfoxy group and a p-toluene sulfoxy group, but is not limited thereto.

In the present specification, the alkyl group in the alkyl thioxy group and the alkyl sulfoxy group is the same as the example of the aforementioned alkyl group. Specifically, the alkyl thioxy group includes a methyl thioxy group, an ethyl thioxy group, a tert-butyl thioxy group, a hexyl thioxy group, an octyl thioxy group, and the alkyl sulfoxy group is mesyl, ethyl sulfoxy group, propyl sulfoxy group, butyl sulfoxy group. And the like, but are not limited thereto.

In the present specification, the divalent linking group is a substituted or unsubstituted alkylene group; A substituted or unsubstituted arylene group; And substituted or unsubstituted N, O, S, Si, Ge may include one or more in the group consisting of a divalent heterocyclic group including one or more of.

In the present specification, an alkylene group means that the alkyl group has two bonding positions, that is, a divalent group. Except that each of these is a divalent group, the description of the alkyl group described above can be applied.

In the present specification, an arylene group means that the aryl group has two bonding positions, that is, a divalent group. Except that each of these is a divalent group, the description of the aryl group described above may be applied.

In the present specification, a heteroarylene group refers to a heteroaryl group having two bonding positions, that is, a divalent group. Except that each of these is a divalent group, the description of the aforementioned heteroaryl group may be applied.

According to an exemplary embodiment of the present specification, in Formula 1, L2 and L3 are the same as or different from each other, and each independently a direct bond; A substituted or unsubstituted alkylene group; A substituted or unsubstituted arylene group; And one or more in the group consisting of a substituted or unsubstituted divalent heterocyclic group including one or more of N, O, S, Si, and Ge.

According to an exemplary embodiment of the present specification, L2 and L3 are the same as or different from each other, and each independently a direct bond; And it includes at least one in the group consisting of a substituted or unsubstituted unsubstituted N, O, S, Si, and a divalent heterocyclic group including at least one of Ge.

According to an exemplary embodiment of the present specification, L2 and L3 are direct bonds.

According to an exemplary embodiment of the present specification, in Formula 1, A1 and A2 are the same as or different from each other, and each independently has any one of the following structures.

In the above structure,

a is an integer from 1 to 7,

b and c are each an integer of 1 to 4,

When a is 2 or more, 2 or more R15 are the same as or different from each other,

When b is 2 or more, 2 or more R16 are the same as or different from each other,

When c is 2 or more, 2 or more R17 are the same as or different from each other,

R14 to R20 are the same as or different from each other, and each independently hydrogen; heavy hydrogen; Halogen group; Nitrile group; Nitro group; Imide group; Amide group; Hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryloxy group; A substituted or unsubstituted alkyl thioxy group; A substituted or unsubstituted arylthioxy group; A substituted or unsubstituted alkyl sulfoxy group; Substituted or unsubstituted arylsulfoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted alkylamine group; A substituted or unsubstituted aralkylamine group; A substituted or unsubstituted arylamine group; A substituted or unsubstituted heteroarylamine group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group including one or more of N, O, and S atoms.

According to an exemplary embodiment of the present specification, in Formula 1, R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; Or a substituted or unsubstituted linear or branched alkyl group.

According to an exemplary embodiment of the present specification, R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; Or a substituted or unsubstituted C 1 to C 30 linear or branched alkyl group.

According to an exemplary embodiment of the present specification, R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; Or a substituted or unsubstituted C 1 to C 20 linear or branched alkyl group.

According to an exemplary embodiment of the present specification, R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; Or a substituted or unsubstituted C 1 to C 10 linear or branched alkyl group.

According to an exemplary embodiment of the present specification, R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; A substituted or unsubstituted octyl group; Or a substituted or unsubstituted 2-ethylhexyl group.

According to an exemplary embodiment of the present specification, R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; Octyl group; Or 2-ethylhexyl group.

According to an exemplary embodiment of the present specification, R4, R8, R24, and R28 are 2-ethylhexyl groups.

According to an exemplary embodiment of the present specification, R9 to R12 are the same as or different from each other, and each independently hydrogen; Or an octyl group.

이고,According to an exemplary embodiment of the present specification, A1 and A2 are the same as or different from each other, and each independently

ego,

R14 is a substituted or unsubstituted linear or branched alkyl group.

이다.According to an exemplary embodiment of the present specification, A1 is

to be.

이다.According to an exemplary embodiment of the present specification, A2 is

to be.

According to an exemplary embodiment of the present specification, R14 is a substituted or unsubstituted linear or branched alkyl group.

According to an exemplary embodiment of the present specification, R14 is a substituted or unsubstituted C1 to C15 linear or branched alkyl group.

According to an exemplary embodiment of the present specification, R14 is a substituted or unsubstituted ethyl group.

According to an exemplary embodiment of the present specification, R14 is an ethyl group.

According to an exemplary embodiment of the present specification, m1 is 1.

According to an exemplary embodiment of the present specification, m2 is 1.

According to an exemplary embodiment of the present specification, n1 is 3.

According to an exemplary embodiment of the present specification, n2 is 3.

According to an exemplary embodiment of the present specification, in Formula 1, G1 and G2 are the same as or different from each other, and each independently a substituted or unsubstituted branched alkyl group having 3 to 10 carbon atoms.

According to an exemplary embodiment of the present specification, in Formula 1, G1 and G2 are the same as or different from each other, and each independently a substituted or unsubstituted 2-ethylhexyl group.

According to an exemplary embodiment of the present specification, in Formula 1, G1 and G2 are 2-ethylhexyl groups.

According to an exemplary embodiment of the present specification, Chemical Formula 1 is represented by Compound 1-1 below.

[Compound 1-1]

The heterocyclic compound may be prepared based on the preparation examples described later.

The heterocyclic compound according to an exemplary embodiment of the present specification is a structure in brackets of m1 and a structure in brackets of m2 are bonded through a benzothiadiazole substituted with a branched alkoxy group as a linking group, and the compound obtained through it is L2, L3 After bonding with, the compound having the structure obtained through it is combined with the compound having the structure in which the aldehyde is introduced at the ends of n1 and n2. Thereafter, A1 and A2 may be introduced to prepare not only the heterocyclic compound represented by compound 1-1, but also the heterocyclic compound represented by Chemical Formula 1.

The heterocyclic compound according to an exemplary embodiment of the present specification may be prepared by a multi-step chemical reaction. After preparing monomers through an alkylation reaction, Grignard reaction, Suzuki coupling reaction, and Stille coupling reaction, the final heterogeneity is obtained through a carbon-carbon coupling reaction such as Steel coupling reaction. Cyclic compounds can be prepared. If the substituent to be introduced is a boronic acid or boronic ester compound, it can be prepared through a Suzuki coupling reaction, and the substituent to be introduced is tributyltin or trimethyltin ) In the case of a compound, it may be prepared through a still coupling reaction, but is not limited thereto.

According to an exemplary embodiment of the present specification, the first electrode; A second electrode provided to face the first electrode; And one or more organic material layers provided between the first electrode and the second electrode and including a photoactive layer, and at least one of the organic material layers includes the heterocyclic compound.

An organic solar cell according to an 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.

According to the exemplary 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.

According to an exemplary embodiment of the present specification, the organic material layer includes a hole transport layer, a hole injection layer, or a layer for simultaneously transporting and injecting holes, and the hole transporting layer, a layer for transporting and injecting holes simultaneously, And the heterocyclic compound.

In another exemplary embodiment, the organic material layer includes an electron injection layer, an electron transport layer, or a layer that simultaneously injects and transports electrons, and the electron injection layer, an electron transport layer, or a layer that simultaneously injects and transports electrons is And the heterocyclic compound.

1 is a diagram showing an organic solar cell according to an exemplary embodiment of the present specification.

According to the exemplary 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.

According to the exemplary 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 organic materials having several functions at the same time.

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

According to the exemplary embodiment of the present specification, the organic solar cell may be arranged in the order of a cathode, a photoactive layer, and an anode, and may be arranged in the order of an anode, a photoactive layer, and a cathode, but is not limited thereto.

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

According to an exemplary embodiment of the present specification, the organic solar cell has a normal structure. In the normal structure, a substrate, an anode, an organic material layer including a photoactive layer, and a cathode may be sequentially stacked.

According to an exemplary embodiment of the present specification, the organic solar cell has an inverted structure. In the inverted structure, a substrate, a cathode, an organic material layer including a photoactive layer, and an anode may be sequentially stacked.

According to an exemplary embodiment of the present specification, the organic solar cell has a tandem structure.

The organic solar cell according to an exemplary embodiment of the present specification may have one or two or more photoactive layers. In the tandem structure, two or more photoactive layers may be included.

In another embodiment, the 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.

According to an exemplary embodiment of the present specification, the photoactive layer includes 1 or 2 or more selected from the group consisting of an electron donor and an acceptor, and the electron donor material includes the heterocyclic compound.

According to an exemplary embodiment of the present specification, the electron acceptor material may be selected from the group consisting of fullerene, fullerene derivatives, vasocuproin, semiconducting elements, semiconducting compounds, and combinations thereof. Specifically, fullerene, a fullerene derivative (PCBM ((6,6)-phenyl-C61-butyric acid-methylester) or PCBCR ((6,6)-phenyl-C61-butyric acid-cholesteryl ester), perylene ( perylene) PBI (polybenzimidazole), and PTCBI (3,4,9,10-perylene-tetracarboxylic bis-benzimidazole) is one or more compounds selected from the group consisting of.

According to an exemplary embodiment of the present specification, the electron donor and electron acceptor constitute a bulk hetero junction (BHJ).

Bulk heterojunction means that an electron donor material and an electron acceptor material are mixed with each other in a photoactive layer.

According to an exemplary embodiment of the present specification, the photoactive layer has a bilayer structure including an n-type organic material layer and a p-type organic material layer, and the p-type organic material layer includes the heterocyclic compound.

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 water resistance, but is not limited thereto, and any substrate commonly used in organic solar cells is not limited thereto. Specifically, there are glass or polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), polyimide (PI), and triacetyl cellulose (TAC). It is not limited thereto.

The anode electrode may be made of a transparent material having excellent conductivity, 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), and indium zinc oxide (IZO); A combination of a metal and an oxide such as ZnO:Al or SNO ₂ :Sb; And conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole and polyaniline, but are not limited thereto. .

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

When the anode electrode is formed on a substrate, it may undergo cleaning, moisture removal, and hydrophilic modification processes.

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

Through the surface modification as described above, the bonding surface potential can be maintained at a level suitable for the surface potential of the photoactive layer. In addition, the formation of a polymer thin film on the anode electrode becomes easy during modification, and the quality of the thin film may be improved.

The pretreatment techniques for the anode electrode include a) a surface oxidation method using parallel plate type discharge, b) a method of oxidizing the surface through ozone generated using UV ultraviolet rays in a vacuum state, and c) oxygen radicals generated by plasma. There is a method of oxidizing by using.

One of the above methods may be selected according to the state of the anode electrode or the substrate. However, regardless of which method is used, it is generally desirable to prevent the oxygen from leaving the anode electrode or the surface of the substrate and to suppress the residual moisture and organic matter as much as possible. In this case, it is possible to maximize the practical effect of the pretreatment.

As a specific example, a method of oxidizing the 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 and dried well, then put into the chamber, and the oxygen gas reacts with the UV light by the action of the UV lamp. The patterned ITO substrate can be cleaned.

However, the method for modifying the surface of the patterned ITO substrate in the present specification is not particularly limited, and any method may be used as long as it is a method of oxidizing the 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; Alternatively, it may be a material having a multilayer structure such as LiF/Al, LiO ₂ /Al, LiF/Fe, Al:Li, Al:BaF ₂ , and Al:BaF ₂ :Ba, 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 material of the hole transport layer and/or the electron transport layer plays a role of efficiently transferring electrons and holes separated in the photoactive layer to an electrode, and the material is not particularly limited.

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

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

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

The preparation method of the heterocyclic compound and the preparation of an organic solar cell including the same will be described in detail in Preparation Examples and Examples below. However, the following examples are for illustrative purposes only, and the scope of the present specification is not limited thereto.

Preparation Example 1. Preparation of compound 1-1

1) Preparation of compound A

After dissolving 2.9 g of starting material 1 in 20 mL of anhydrous tetrahydrofuran, it was cooled to -78°C. 2.0 mL of 2.5M n-BuLi was added to the resulting solution, followed by stirring for 2 hours. After injecting 5.4 mL of 1.0M Me ₃ SnCl into the reaction mixture obtained through this, the reaction mixture was heated to room temperature and stirred for 12 hours. The reaction was quenched by adding 20 mL of water to the reaction mixture obtained through this, and the organic layer was extracted three times using 20 mL of ethyl acetate. The organic layer obtained through this was dried over MgSO ₄ and then filtered, and the resulting solution was decompressed to remove the solvent to obtain compound A.

2) Preparation of compound B

After adding 45 mg of Pd ₂ (dba) ₃ and 26 mg of P( o- tol) ₃ to the reaction vessel, a solution obtained by dissolving 1.57 g of Compound A and 389 mg of starting material 2 in 13 mL of toluene was injected. I did. The reaction mixture obtained through this was stirred at 90 over 3 days, cooled to room temperature, and extracted three times using 20 mL of water and the same amount of chloroform. The organic layer obtained through this was dried over MgSO ₄ and then filtered, and the resulting solution was decompressed to remove the solvent to obtain a red oil. This oil was subjected to flash column using chloroform:hexane (1:2 by volume) as a developing solvent to obtain compound B in a yield of 90%.

3) Preparation of compound C

1.9 g of Compound B was dissolved in 50 mL of anhydrous tetrahydrofuran, and then cooled to -78. 4.9 mL of 1.0 M Lithium diisopropylamide (LDA) was injected into the resulting solution, followed by stirring for 2 hours. After injecting 4.9 mL of 1.0M Me ₃ SnCl into the reaction mixture obtained through this, the reaction mixture was heated to room temperature and stirred for 12 hours. The reaction was quenched by adding 50 mL of water to the reaction mixture obtained through this, and the organic layer was extracted three times using 30 mL of chloroform. The organic layer obtained through this was dried over MgSO ₄ and then filtered, and the resulting solution was decompressed to remove the solvent to obtain compound C.

4) Preparation of compound E

69 mg of Pd ₂ (dba) ₃ and 39 mg of P( o- tol) ₃ were added to the reaction vessel, and a solution obtained by dissolving 2.0 g of compound C and 1.9 g of compound D in 45 mL of toluene was injected into the mixture. I did. The reaction mixture obtained through this was stirred at 90 over 3 days, cooled to room temperature, and extracted three times using 40 mL of water and the same amount of chloroform. The organic layer obtained through this was dried over MgSO ₄ and then filtered, and the resulting solution was decompressed to remove the solvent to obtain a red oil. Dichloromethane:hexane (3:4 volume ratio) of this oil was flash columned with a developing solvent to obtain compound B in a yield of 43%.

5) Preparation of compound 1-1

After 1.2 g of Compound E was dissolved in 30 mL of chloroform, 4 drops of piperidine and 760 mg of 2-ethylrhodanin were added to this solution, followed by stirring at a temperature of 70 for 12 hours. Thereafter, the reaction mixture was cooled to room temperature, filtered through silica gel using chloroform, and the solvent was removed through reduced pressure. The mixture obtained through this was flash-column using hexane and chloroform, and then recrystallized using ethyl acetate and dichloromethane to obtain compound 1-1 in a yield of 67%.

The NMR data of Compound 1-1 are shown in FIG. 2.

Example 1. Fabrication of organic solar cell

Compound 1-1 and PC ₇₁ BM were dissolved at 1:2 in chloroform (CF) to prepare a composite solution. At this time, the concentration was adjusted to 4 wt%, and the organic solar cell had an inverted structure of ITO/ZnO/photoactive layer/MoO ₃ /Ag.

ITO is a bar type, and the glass substrate coated with 1.5 × 1.5 cm ² is ultrasonically cleaned using distilled water, acetone, and 2-propanol, and the ITO surface is ozone treated for 10 minutes, and then a zinc oxide precursor (ZnO precursor). solution: ZnO nanoparticle 25mg/ml in butanol), spin-coating this zinc oxide (ZnO) solution at 4000 rpm for 40 seconds, heat treatment at 100 for 10 minutes to remove the remaining solvent and remove the electron transport layer Was completed. To coat the photoactive layer, a composite solution of polymer 1 and PC ₇₁ BM was spin-coated at 1000 rpm for 20 seconds. MoO ₃ was deposited in a thickness of 10 nm at a rate of 0.2 Å/s in a thermal evaporator to prepare a hole transport layer. After manufacturing in the above order, 100 nm of Ag was deposited at a rate of 1 Å/s inside the thermal evaporator to prepare an organic solar cell having a reverse structure.

Example 2. Fabrication of organic solar cell

An organic solar cell was manufactured in the same manner as in Example 1, except that chlorobenzene (CB) was used instead of chloroform.

Example 3. Fabrication of organic solar cell

An organic solar cell was manufactured in the same manner as in Example 1, except that o -xylene was used instead of chloroform.

Comparative Example 1. Fabrication of organic solar cell

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

[Comparative Example Compound 1]

Comparative Example 2. Fabrication of Organic Solar Cell

An organic solar cell was manufactured in the same manner as in Comparative Example 1, except that chlorobenzene (CB) was used instead of chloroform.

Comparative Example 3. Fabrication of Organic Solar Cell

An organic solar cell was manufactured in the same manner as in Comparative Example 1, except that o -xylene was used instead of chloroform.

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

V _OC (V) J _SC (mA/cm ² ) FF (%) PCE (%) Example 1 0.936 10.720 0.542 5.44 Example 2 0.941 9.171 0.533 4.60 Example 3 0.836 11.605 0.599 5.99 Comparative Example 1 0.835 12.366 0.576 5.94 Comparative Example 2 0.908 4.639 0.544 2.29 Comparative Example 3 0.878 8.931 0.369 2.89

According to Table 1, the organic solar cell prepared by the heterocyclic compound according to an exemplary embodiment of the present specification in which G1 and G2 of Formula 1 includes an alkyl group having a branched chain is represented by Formula 1 used in Comparative Examples 1 to 3 above. It can be seen that G1 and G2 exhibit higher efficiency than the organic solar cell prepared with Comparative Example Compound 1, which is a linear alkyl group.

V _oc is an open-circuit voltage, J _sc is a short-circuit current, FF is a fill factor, and PCE (η) is an energy conversion efficiency. The open-circuit voltage and the short-circuit current are the X-axis 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. Also, the fill factor is a value obtained by dividing the area of a rectangle that can be drawn inside the curve by the product of the short-circuit current and the open-circuit voltage. By dividing these three values by the intensity of the irradiated light, the energy conversion efficiency can be obtained, and the higher the value, the more preferable. As a result of Table 1, it can be seen that the heterocyclic compound according to an exemplary embodiment of the present specification exhibits high efficiency.

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

Claims (12)

Heterocyclic compound represented by the following formula (1):
[Formula 1]

In Formula 1,
m1 and m2 are 3, the structures in the three brackets are the same or different from each other,
L2 and L3 are direct bonds,
R1 to R12 and R21 to R28 are the same as or different from each other, and each independently hydrogen; Or a straight or branched alkyl group having 1 to 10 carbon atoms,
G1 and G2 are the same as or different from each other, and each independently a branched alkyl group having 3 to 10 carbon atoms,
A1 and A2 are the same as or different from each other, and each independently

ego,
R14 is a C1-C15 linear or branched alkyl group. delete delete delete delete The heterocyclic compound of claim 1, wherein the formula 1 is represented by the following compound 1-1:
[Compound 1-1]

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 and including a photoactive layer, wherein at least one of the organic material layers comprises the heterocyclic compound according to any one of claims 1 and 6 Organic solar cell comprising. The method according to claim 7, wherein the organic material layer comprises a hole transport layer, a hole injection layer, or a layer that simultaneously transports and injects holes,
The hole transport layer, the hole injection layer, or a layer for simultaneously transporting and injecting holes is an organic solar cell comprising the heterocyclic compound. The method of claim 7, wherein the organic material layer comprises an electron injection layer, an electron transport layer, or a layer that simultaneously injects and transports electrons,
The electron injection layer, the electron transport layer, or the layer that simultaneously injects and transports electrons and transports electrons at the same time includes the heterocyclic compound. The method of claim 7, wherein the photoactive layer comprises one or two or more selected from the group consisting of an electron donor and an electron acceptor,
The electron donor is an organic solar cell comprising the heterocyclic compound. The organic solar cell of claim 10, wherein the electron donor and electron acceptor constitute a bulk hetero junction (BHJ). The method according to claim 7, wherein the photoactive layer is a two-layer thin film (bilayer) structure comprising an n-type organic material layer and a p-type organic material layer,
The p-type organic material layer is an organic solar cell comprising the heterocyclic compound.

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