KR102491797B1 - Polymer and organic electronic device comprising the - Google Patents

Abstract

The present specification relates to a polymer including a unit represented by Formula 1 and an organic electronic device including the polymer in an organic active layer.

Description

Polymer and organic electronic device including the same {POLYMER AND ORGANIC ELECTRONIC DEVICE COMPRISING THE}

The present specification relates to a polymer and an organic electronic device including the same.

In this specification, an organic electronic device is an electronic device using an organic semiconductor material, and requires exchange of holes and/or electrons between an electrode and an organic semiconductor material. Organic electronic devices can be largely divided into two types as follows according to the operation principle. First, excitons are formed in the organic material layer by photons introduced into the device from an external light source, and these excitons are separated into electrons and holes, and these electrons and holes are transferred to different electrodes and used as a current source (voltage source) It is an electronic device in the form of The second type is an electronic device in which a voltage or current is applied to two or more electrodes to inject holes and/or electrons into an organic semiconductor material layer forming an interface with the electrodes, and operate by the injected electrons and holes.

Examples of the organic electronic device include an organic solar cell, an organic photoelectric device, an organic light emitting device, an organic photoconductor (OPC), and an organic transistor, all of which are electron/hole injection materials, electron/hole extraction materials, and electrons for driving devices. /requires a hole transport material or a light emitting material. Hereinafter, an organic solar cell will be described in detail, but in the organic electronic devices, electron/hole injection materials, electron/hole extraction materials, electron/hole transport materials, or light emitting materials all work on a similar principle.

A solar cell is a battery that directly changes electrical energy from sunlight, and research is being actively conducted because it is a clean alternative energy source to solve global environmental problems caused by the depletion of fossil energy and its use. Here, the solar cell refers to a cell that absorbs light energy from sunlight and generates current-voltage using a photovoltaic effect in which electrons and holes are generated.

A solar cell is a device capable of directly converting solar energy into electrical energy by applying a photovoltaic effect. Solar cells can be divided into inorganic solar cells and organic solar cells according to the materials constituting the thin film.

Through the change of various layers and electrodes according to the design of the solar cell, a lot of research is being conducted to increase the energy conversion efficiency.

Two-layer organic photovoltaic cell (C.W.Tang, Appl. Phys. Lett., 48, 183. (1986)) 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 invention is to provide a polymer and an organic electronic device comprising the same.

An exemplary embodiment of the present specification provides a polymer including a unit represented by Formula 1 below.

[Formula 1]

In Formula 1,

R1 to R10 are each hydrogen; A substituted or unsubstituted alkyl group; Or a substituted or unsubstituted alkoxy group,

At least one of R7 to R10 is a substituted or unsubstituted alkoxy group,

X1 and X2 are each hydrogen; halogen group; Or a substituted or unsubstituted alkyl group,

Ar is a substituted or unsubstituted divalent thiophene group; A substituted or unsubstituted divalent bithiophene group; A substituted or unsubstituted divalent thienothiophene group; Or a substituted or unsubstituted divalent dithienothiophene group,

p and q are each an integer of 0 to 3, and when p or q is 2 or more, they are the same as or different from each other.

In addition, an exemplary embodiment of the present specification

A composition for forming an organic active layer of an organic electronic device comprising the polymer is provided.

In addition, an exemplary embodiment of the present specification

a first electrode;

a second electrode provided to face the first electrode; and

It is provided between the first electrode and the second electrode and includes one or more organic material layers including an organic active layer,

The organic active layer provides an organic electronic device comprising the polymer.

The polymer according to an exemplary embodiment of the present specification has the advantage of being able to freely control the HOMO/LUMO energy level, and when applied to an organic electronic device, the charge balance can be adjusted, so that excellent performance can be exhibited.

In addition, the polymer according to an exemplary embodiment of the present specification can be subjected to both a solution process and a deposition process, and thus is advantageous for introduction into an organic electronic device.

1 is a diagram illustrating an organic solar cell according to an exemplary embodiment of the present specification.
Figure 2 is a diagram showing the NMR spectrum of the terminal group of Compound 2 prepared in Preparation Example of the present application.
3 is a graph showing UV-Vis absorption spectra of the polymer 1-1 and a comparative compound in a film state.

Hereinafter, this specification will be described in more detail.

In one embodiment of the present specification, the polymer includes a unit represented by Formula 1 below.

[Formula 1]

In Formula 1,

R1 to R10 are each hydrogen; A substituted or unsubstituted alkyl group; Or a substituted or unsubstituted alkoxy group,

At least one of R7 to R10 is a substituted or unsubstituted alkoxy group,

X1 and X2 are each hydrogen; halogen group; Or a substituted or unsubstituted alkyl group,

Ar is a substituted or unsubstituted divalent thiophene group; A substituted or unsubstituted divalent bithiophene group; A substituted or unsubstituted divalent thienothiophene group; Or a substituted or unsubstituted divalent dithienothiophene group,

p and q are each an integer of 0 to 3, and when p or q is 2 or more, they are the same as or different from each other.

Conventional research on organic electronic devices has focused on finding high-efficiency electron donor materials when the electron acceptor of the organic active layer is a fullerene compound such as PCBM. Since the performance of devices such as lifespan is reaching a limit, research on using non-fullerene-based compounds such as ITIC as an electron acceptor is increasing.

Among non-fullerene-based compounds, monomolecular compounds have a problem in terms of device life. Accordingly, the inventors of the present invention developed a polymer having the unit of Formula 1 as a repeating unit by introducing a thiophene containing an alkoxy group into a molecule containing Si and then copolymerizing with an Ar unit having an electron donating nature. did Since the length of the conjugation bond increases in the process of polymerization, the absorption region can be extended to long wavelengths, and when used with a polymer electron donor material, mechanical properties of an organic electronic device compared to a low molecular electron acceptor material. has the effect of increasing Therefore, the polymer can be applied to both a solution process and a deposition process when manufacturing an organic electronic device.

In addition, since the polymer has a strong interaction between the oxygen atom of the alkoxy group and the sulfur atom of the neighboring thiophene and contains a strong electron donating unit including Si, absorption in a very wide range of up to 1,000 nm can be achieved. have This means that it can be an electron acceptor material with excellent performance when applied to an organic electronic device.

In this specification, when a certain part is said to 'include' a certain component, this means that it may further include other components, not excluding other components unless otherwise stated.

In this specification, when a member is said to be located 'on' another member, this includes not only a case where a member is in contact with another member, but also a case where another member exists between the two members.

In this specification, the energy level means the magnitude of energy. Therefore, even when an energy level is displayed in a negative (-) direction from a vacuum level, the energy level is interpreted as meaning an absolute value of the corresponding energy value. For example, the HOMO energy level means the distance from the vacuum level to the highest occupied molecular orbital. In addition, the LUMO energy level means the distance from the vacuum level to the lowest unoccupied molecular orbital.

In the present specification, the term 'substitution' means that a hydrogen atom bonded to a carbon atom of a compound is changed to another substituent, and the position to be substituted is not limited as long as the hydrogen atom is substituted, that is, the position where the substituent is substituted, 2 In the case of multi-substitution, two or more substituents may be the same as or different from each other.

In this specification, the term 'substituted or unsubstituted' means deuterium; halogen group; hydroxy group; an alkyl group; cycloalkyl group; alkoxy group; aryloxy group; alkenyl group; aryl group; And it means that it is substituted with one or more substituents selected from the group consisting of a heterocyclic group, or is substituted with a substituent in which two or more substituents from among the above exemplified substituents are connected, or does not have any substituents.

In the present specification, the number of carbon atoms of a substituent having a branched chain includes the number of carbon atoms of the branched chain. For example, in 'an alkyl group having 3 to 20 carbon atoms having at least one methyl group as a branched chain', '3 to 20' is a numerical value including the number of carbon atoms of the 'at least one methyl group'.

In the present specification, the alkyl group may be straight-chain or branched-chain, 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-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, iso Pentyl, 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, 2-methylhexyl, 4-methylhexyl and 5-methylhexyl, but is not limited thereto.

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

In one embodiment of the present specification, Ar is a divalent thiophene group.

In one embodiment of the present specification, Ar is a divalent thiophene group substituted with a halogen group.

In one embodiment of the present specification, Ar is a divalent thiophene group substituted with fluorine.

In one embodiment of the present specification, Ar is a divalent thienothiophene group.

In one embodiment of the present specification, Ar is a divalent dithienothiophene group.

In one embodiment of the present specification, Ar is a divalent bithiophene group.

In one embodiment of the present specification, Ar is a divalent bithiophene group substituted with a halogen group.

In one embodiment of the present specification, Ar is a divalent bithiophene group substituted with fluorine.

In one embodiment of the present specification, Chemical Formula 1 is any one of Chemical Formulas 2-1 to 2-4 below.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

In Formulas 2-1 to 2-4,

R1 to R10, X1, X2, p and q are the same as those defined in Formula 1 above,

R11 to R20 are each hydrogen or a halogen group.

In one embodiment of the present specification, R1 to R4 are each hydrogen.

In one embodiment of the present specification, R5 and R6 are each a substituted or unsubstituted alkyl group.

In one embodiment of the present specification, R5 and R6 are each a straight-chain or branched-chain alkyl group having 1 to 30 carbon atoms.

In one embodiment of the present specification, R5 and R6 are each a straight-chain or branched-chain alkyl group having 3 to 20 carbon atoms.

In one embodiment of the present specification, R5 and R6 are each a straight-chain or branched-chain alkyl group having 5 to 10 carbon atoms.

In one embodiment of the present specification, each of R5 and R6 is an ethylhexyl group.

In an exemplary embodiment of the present specification, each of R5 and R6 is a 2-ethylhexyl group.

In one embodiment of the present specification, each of R7 to R10 is hydrogen; Or a substituted or unsubstituted alkoxy group.

In an exemplary embodiment of the present specification, one of R7 and R8 is a (2-butyldecyl)oxy group and the other is hydrogen, and one of R9 and R10 is a (2-butyldecyl)oxy group, the other one is hydrogen;

In an exemplary embodiment of the present specification, one of R7 and R8 is a (2-ethylhexyl)oxy group and the other is hydrogen, and one of R9 and R10 is a (2-ethylhexyl)oxy group, the other one is hydrogen;

In one embodiment of the present specification, R7 and R10 are each hydrogen, and R8 and R9 are alkoxy groups.

In one embodiment of the present specification, R8 and R9 are each a straight-chain or branched-chain alkoxy group having 1 to 30 carbon atoms.

In one embodiment of the present specification, R8 and R9 are each a straight-chain or branched-chain alkoxy group having 3 to 20 carbon atoms.

In one embodiment of the present specification, R8 and R9 are each a straight-chain or branched-chain alkoxy group having 5 to 15 carbon atoms.

In one embodiment of the present specification, each of R8 and R9 is a (butyldecyl)oxy group.

In one embodiment of the present specification, each of R8 and R9 is an (ethylhexyl)oxy group.

In one embodiment of the present specification, each of R11 to R20 is hydrogen.

In one embodiment of the present specification, each of R11 and R12 is a halogen group.

In one embodiment of the present specification, each of R11 and R12 is fluorine.

In one embodiment of the present specification, R13 and R14 are each hydrogen.

In one embodiment of the present specification, R15 and R16 are each hydrogen.

In one embodiment of the present specification, each of R17 to R20 is hydrogen.

In one embodiment of the present specification, one of R17 and R18 is a halogen group and the other is hydrogen, and one of R19 and R20 is a halogen group and the other is hydrogen.

In one embodiment of the present specification, one of R17 and R18 is fluorine and the other is hydrogen, and one of R19 and R20 is fluorine and the other is hydrogen.

In one embodiment of the present specification, each of R17 and R20 is hydrogen, and each of R18 and R19 is a halogen group.

In an exemplary embodiment of the present specification, each of R17 and R20 is hydrogen, and each of R18 and R19 is fluorine.

In one embodiment of the present specification, Formula 1 is represented by Formula 3 below.

[Formula 3]

In Formula 3,

R5, R6, Ar, X1, X2, p and q are the same as defined in Formula 1 above,

R21 and R22 are each a substituted or unsubstituted alkyl group.

In one embodiment of the present specification, R21 and R22 are each a straight-chain or branched-chain alkyl group having 1 to 30 carbon atoms.

In one embodiment of the present specification, R21 and R22 are each a straight-chain or branched-chain alkyl group having 3 to 20 carbon atoms.

In one embodiment of the present specification, R21 and R22 are each a straight-chain or branched-chain alkyl group having 5 to 15 carbon atoms.

In one embodiment of the present specification, R21 and R22 are each a butyldecyl group.

In one embodiment of the present specification, R21 and R22 are each a 2-butyldecyl group.

In one embodiment of the present specification, R21 and R22 are each an ethylhexyl group.

In one embodiment of the present specification, R21 and R22 are each a 2-ethylhexyl group.

In one embodiment of the present specification, Formula 1 is represented by any one of Formulas 3-1 to 3-4 below.

[Formula 3-1]

[Formula 3-2]

[Formula 3-3]

[Formula 3-4]

In Formulas 3-1 to 3-4,

R5, R6, X1, X2, p and q are the same as defined in Formula 1 above,

R11 to R20 are each hydrogen or a halogen group,

R21 and R22 are each a substituted or unsubstituted alkyl group.

In one embodiment of the present specification, each of X1 and X2 is hydrogen.

In one embodiment of the present specification, X1 and X2 are each a straight-chain alkyl group having 1 to 10 carbon atoms.

In one embodiment of the present specification, each of X1 and X2 is a methyl group.

In one embodiment of the present specification, each of X1 and X2 is a halogen group.

In one embodiment of the present specification, each of X1 and X2 is fluorine.

In one embodiment of the present specification, p and q are each an integer of 0 to 2, and when p or q is 2, they are the same as or different from each other.

In one embodiment of the present specification, p and q are each 0 or 1.

In one embodiment of the present specification, Formula 1 is any one selected from Formulas 1-1 to 1-6 below.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Formula 1-6]

In one embodiment of the present specification, the repeating number of the unit represented by Chemical Formula 1 may be 1 to 10,000.

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

In one embodiment of the present specification, the terminal group of the polymer is a 4- (trifluoromethyl) phenyl group.

In one embodiment of the present specification, the terminal group of the polymer is a bromo-thiophene group.

In one embodiment of the present specification, the terminal group of the polymer is a trifluoro-benzene group.

In one embodiment of the present specification, the number average molecular weight of the polymer is 10,000 g / mol to 100,000 g / mol, preferably 30,000 g / mol to 50,000 g / mol.

According to one embodiment of the present specification, the polymer may have a molecular weight distribution of 1 to 10. It may preferably have a molecular weight distribution of 1 to 5, more preferably 1 to 2.

In one embodiment of the present specification, the polymer exhibits an absorption region of 300 nm to 1,000 nm, and preferably has a maximum absorption wavelength at 700 nm to 900 nm.

Accordingly, when applied to an organic electronic device, it exhibits complementary absorption with the absorption region (300 nm to 700 nm) of the electron donor, so that a high short-circuit current can be exhibited when applied to an organic electronic device.

In one embodiment of the present specification, the polymer is capable of absorbing light in the visible ray full-wave region, and can also absorb light in the infrared region. Accordingly, the effect of a wide absorption wavelength range of the device can be exhibited.

In one embodiment of the present specification, a composition for forming an organic active layer of an organic electronic device includes the polymer.

In one embodiment of the present specification, the polymer is included in an amount of 0.5 wt% to 5 wt%, preferably 1 wt% to 3 wt%, based on 100 wt% of the composition.

When the content of the polymer is less than 0.5wt%, it is difficult to form a thin film, and when it exceeds 5wt%, it is difficult to form a clean thin film due to solubility problems.

In one embodiment of the present specification, the composition may further include an electron donor material described below, and the content of the electron donor material may be 0.5 wt% to 5 wt% based on 100 wt% of the composition.

In one embodiment of the present specification, the composition may further include, but is not limited to, chlorobenzene as a solvent, and all of the composition except for the polymer and the electron donor may be a solvent.

In one embodiment of the present specification, an organic electronic device includes a 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 an organic active layer, wherein the organic active layer includes the polymer.

In addition, in one embodiment of the present specification, a method of manufacturing an organic electronic device includes forming a first electrode on a substrate; forming an electron transport layer on the first electrode; forming one or more organic material layers including an organic active layer on the electron transport layer; and forming a second electrode on the organic material layer, wherein the organic active layer includes the polymer.

After manufacturing the organic electronic device, the existence of the polymer can be confirmed through EQE spectrum.

In one embodiment of the present specification, the step of forming one or more organic material layers including the organic active layer is performed by a spin-coating method, and the spin-coating speed may be 700 rpm to 1,300 rpm. .

When the spin-coating speed is within the above range, the thickness of the organic active layer is formed to be about 100 nm, so that the performance of the organic electronic device can be improved.

The organic electronic device of the present invention may be manufactured by conventional organic electronic device manufacturing methods and materials, except that the polymer containing the unit represented by Chemical Formula 1 is included in the organic active layer.

In one embodiment of the present specification, the organic active layer includes an electron donor and an electron acceptor, and the electron acceptor includes the polymer.

In the present specification, the organic active layer may be a photoactive layer or a light emitting layer.

In the present specification, the organic electronic device may be an organic solar cell, an organic photoelectric device, an organic light emitting device, an organic photoconductor (OPC), or an organic transistor.

In one embodiment of the present specification, the organic electronic device is an organic solar cell.

In one embodiment of the present specification, the organic electronic device is an organic photoelectric device, preferably an organic photodiode.

Below, an organic solar cell is illustrated. In the organic solar cell, the organic active layer is a photoactive layer, and the description of the organic solar cell to be described later can be cited for the organic electronic device described above.

In one embodiment of the present specification, an organic solar cell includes a 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, wherein the photoactive layer includes the polymer.

The organic solar cell may further include a substrate, a hole transport layer, a hole injection layer, an electron injection layer, and/or an electron transport layer.

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 organic materials having multiple functions at the same time.

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

In one embodiment of the present specification, the electron donor may use a material applied in the art, for example, poly 3-hexyl thiophene (P3HT), PCDTBT (poly[N-9 '-heptadecanyl-2,7-carbazole-alt-5,5-(4'-7'-di-2-thienyl-2',1',3'-benzothiadiazole)]), PCPDTBT(poly[2,6 -(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] ), PFO-DBT (poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(4,7-bis(thiophene-2-yl)benzo-2,1,3-thiadiazole)] ), PTB7 (Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2- [(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]), PSiF-DBT(Poly[2,7-(9,9-dioctyl-dibenzosilole)-alt-4,7-bis(thiophene -2-yl)benzo-2,1,3-thiadiazole]), PTB7-Th (Poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b; 4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl) ]) and PBDB-T (poly(benzodithiophene-benzotriazole).

In one embodiment of the present specification, the electron donor is PBDB-T.

In one embodiment of the present specification, the mass ratio of the electron donor and the electron acceptor may be 1:2 to 2:1, preferably 1:1.5 to 1.5:1, more preferably 1:1. there is.

In one embodiment of the present specification, the electron donor and electron acceptor may constitute a bulk heterojunction (BHJ). A bulk heterojunction means that an electron donor material and an electron acceptor material are mixed with each other in the photoactive layer.

In one embodiment of the present specification, the electron donor may be a p-type organic compound layer, and the electron acceptor may be an n-type organic compound layer.

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

In another 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, or may be arranged in the order of a cathode, an electron transport layer, a photoactive layer, a hole transport layer, and an anode. , but not limited thereto.

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

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

1 is a diagram illustrating an organic solar cell 100 according to an exemplary embodiment of the present specification. According to FIG. 1, in the organic solar device 100, when light is incident from the side of the first electrode 101 and/or the second electrode 105 and the photoactive layer 103 absorbs light in the entire wavelength range, excitons are generated from the inside. this can be created. Excitons are separated into holes and electrons in the photoactive layer 103, and the separated holes move toward the anode, which is one of the first electrode 101 and the second electrode 105, and the separated electrons move to the first electrode 101 and the second electrode 105. It moves to the other one of the second electrodes 105, that is, the cathode, so that current can flow through the organic solar cell.

In one embodiment of the present specification, the organic solar cell has a tandem structure. In this case, the organic solar cell may include two or more photoactive layers.

An organic solar cell according to an exemplary embodiment of the present specification may have one or more photoactive layers.

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. At this time, 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 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 is limited as long as it is a substrate commonly used in organic solar cells. It doesn't work. Specifically, there are glass, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene), PI (polyimide), and TAC (triacetyl cellulose). It is not limited to this.

The material of the first electrode may be a material that is transparent and has excellent conductivity, but is not limited thereto. For example, 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); combinations of metals and oxides 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 first electrode is not particularly limited, but, for example, sputtering, E-beam, thermal evaporation, spin coating, screen printing, inkjet printing, doctor blade or gravure printing may be used.

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

For example, the patterned ITO substrate is sequentially cleaned with detergent, acetone, and isopropyl alcohol (IPA), and then heated on a heating plate at 100° C. to 150° C. for 1 minute to 30 minutes, preferably at 120° C. for 10 minutes to remove moisture. After drying and when the substrate is completely cleaned, the surface of the substrate 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, when reforming, it is easy to form a polymer thin film on the first electrode, and the quality of the thin film may be improved.

Pretreatment technologies for the first electrode include a) surface oxidation using parallel plate discharge, b) surface oxidation using ozone generated using UV rays in a vacuum state, and c) oxygen generated by plasma. There are methods of oxidation using radicals.

One of the above methods may be selected according to the state of the first electrode or substrate. However, regardless of which method is used, it is desirable to prevent oxygen escape from the surface of the first electrode or the substrate and to suppress the remaining moisture and organic matter as much as possible. At this time, the practical effect of the pretreatment can be maximized.

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, dried well, put into a chamber, and a UV lamp is operated to generate oxygen gas by reacting with UV light to generate ozone. The patterned ITO substrate can be cleaned.

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

The second electrode may be a metal having a low work function, but is not limited thereto. Specifically, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; 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 second electrode may be deposited and formed inside a thermal evaporator exhibiting a degree of vacuum of 5 × 10 ^-7 torr or less, but is not limited to this method.

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

The hole transport layer material is 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 ) It may be the like, but is not limited only to these.

The electron transport layer material may be bathocuproine (BCP) or electron-extracting metal oxides, specifically, bathocuproine (BCP); metal complexes 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 ).

In one embodiment of the present specification, a vacuum deposition method or a solution coating method may be used as a method of forming the photoactive layer, and the solution coating method refers to a photoactive material such as an electron donor and/or an electron acceptor in an organic solvent. After dissolution, it means a method of applying the solution by a method such as spin coating, dip coating, screen printing, spray coating, doctor blade and brush painting, but is not limited to these methods.

In one embodiment of the present specification, the polymer may be prepared by a manufacturing method described below. Representative examples are described in the preparation examples to be described later, but, if necessary, substituents may be added or excluded, and the position of the substituent may be changed. In addition, based on techniques known in the art, starting materials, reactants, and reaction conditions may be changed.

In addition, examples will be described in detail in order to specifically describe the present specification. However, the embodiments according to the present specification may be modified in many different forms, and the scope of the present specification is not construed as being limited to the embodiments described below. The embodiments herein are provided to more completely explain the present specification to those skilled in the art.

<Preparation Example 1: Preparation of Compounds 1 and 2>

(1) Preparation of compound 1

Pd2( 0.43 g of dba)3 and 0.57 g of tri(o-tolyl)phosphine were dissolved in 150 ml of toluene and refluxed. When the temperature reached 100 °C, 10.71 g (2.5 eq) of 5-bromo-4-((2-butyldecyl)oxy)thiophene-2-carbaldehyde was dissolved in 5 mL of toluene, slowly injected, and refluxed for 12 hours. After the reaction was completed, the compound 1 was obtained through column chromatography.

(2) Preparation of compound 2

In a round flask equipped with a condenser, 1.5 g of Compound 1 prepared in (1) and 1.2 g of 2-(6-bromo-3-oxo-2,3-dihydro-1H-inden-1-ylidene) malononitrile were mixed with 10 mL of chloroform. was dissolved in and 1 mL of pyridine was injected, followed by refluxing at 60 °C for 12 hours. After filtering through methanol, compound 2 was obtained through column chromatography.

However, 2-(6-bromo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile used here has bromine positions 5 and 6 mixed in a mass ratio of 3:7, respectively. , and its NMR spectrum is shown in FIG. 2 .

<Preparation Example 2: Preparation of Comparative Compound>

In (2) of Preparation Example 1, 2-(3-oxo-2,3-dihydro- (2) of Preparation Example 1 except for using 1H-inden-1-ylidene) malononitrile The comparative compound was prepared by performing the same procedure as above.

<Preparation Example 3: Preparation of Polymers 1-1 to 1-4>

(1) Preparation of Polymer 1-1

300mg of the compound 2, 80mg (1.0eq) of 2,5-bis(trimethylstannyl)thiophene, and 0.01g (0.03eq) of Pd(PPh ₃ ) ₄ were injected into a round flask equipped with a condenser, and then 10mL of toluene was injected. Thereafter, the mixture was refluxed at 100° C. for 17 hours, the reaction was terminated with methanol, and the synthesized polymer was purified with methanol, nucleic acid and acetone to obtain polymer 1-1. <Mn:19,000, PDI: 1.25>

(2) Preparation of Polymer 1-2

Except for using (3,4-difluorothiophene-2,5-diyl)bis(trimethylstannane) instead of 2,5-bis(trimethylstannyl)thiophene in the preparation of Polymer 1-1, the manufacturing method of Polymer 1-1 and The polymer 1-2 was prepared in the same manner. <Mn: 17,000, PDI: 1.30>

(3) Preparation of Polymer 1-3

Except for using 5,5'-bis(trimethylstannyl)-2,2'-bithiophene instead of 2,5-bis(trimethylstannyl)thiophene in the preparation of Polymer 1-1, the method for preparing Polymer 1-1 is identical. The process was carried out to prepare the polymer 1-3. <Mn: 18,500, PDI: 1.40>

(4) Preparation of Polymers 1-4

Except for using (3,3'-difluoro-[2,2'-bithiophene]-5,5'-diyl)bis(trimethylstannane) instead of 2,5-bis(trimethylstannyl)thiophene in the preparation of Polymer 1-1. Then, the polymer 1-4 was prepared by performing the same process as the preparation method of the polymer 1-1. <Mn:17,000, PDI: 1.60>

(5) Preparation of Polymers 1-5

Method for preparing Polymer 1-1 except for using 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene instead of 2,5-bis(trimethylstannyl)thiophene in the preparation of Polymer 1-1 Polymers 1-5 were prepared by the same procedure as <Mn: 16,000, PDI: 1.40>

(6) Preparation of polymers 1-6

Except for using 2,6-bis (trimethylstannyl) dithieno [3,2-b: 2', 3'-d] thiophene instead of 2,5-bis (trimethylstannyl) thiophene in the preparation of polymer 1-1, Polymer 1-6 was prepared in the same manner as in the preparation method of Polymer 1-1. <Mn:12,000, PDI: 1.20>

<Example: Preparation of organic solar cell>

Example 1.

(1) Preparation of composite solution

The compound poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene) )-Alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5 '-c']dithiophene-4,8-dione))](poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)- benzo[1, 2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'- bis(2-ethylhexyl)benzo[1 ',2'-c:4',5'-c']dithiophene-4,8-dione))], PBDB-T) (Mn: 25,000 g/mol, Solarmer Co.) as an electron donor material, prepared above Polymer 1-1 synthesized in Example was used as an electron acceptor material and dissolved in chlorobenzene (CB) at a mass ratio of 1:1 to prepare a composite solution having a concentration of 2 wt%.

(2) Manufacture of organic solar cells

A glass substrate (11.5Ω/□) coated with a 1.5×1.5cm ² bar type of ITO was ultrasonically cleaned using distilled water, acetone, and 2-propanol, and the ITO surface was treated with ozone for 10 minutes to remove it. 1 electrode was formed.

After spin-coating a ZnO nanoparticle solution (N-10, Nanograde Ltd, 2.5 wt% in 1-butanol, filtered through 0.45 μm PTFE) at 4,000 rpm for 40 seconds on the first electrode, An electron transport layer was formed by removing the remaining solvent by heat treatment at 80° C. for 10 minutes.

Thereafter, the composite solution prepared in (1) was spin-coated for 25 seconds at 700 rpm at 70° C. on the electron transport layer to form a photoactive layer, and MoO ₃ was applied on the photoactive layer at a rate of 0.2 Å/s and 10 A hole transport layer was formed by thermal evaporation to a thickness of 10 nm under ^-7 torr vacuum.

Thereafter, Ag was deposited to a thickness of 100 nm at a rate of 1 Å/s inside a thermal evaporator to form a second electrode, thereby manufacturing an organic solar cell having an inverted structure.

Example 2.

An organic solar cell was manufactured in the same manner as in Example 1, except that the composite solution prepared in (1) was spin-coated at 900 rpm when the photoactive layer was formed in Example 1.

Example 3.

An organic solar cell was manufactured in the same manner as in Example 1, except that the composite solution prepared in (1) was spin-coated at 1,100 rpm when the photoactive layer was formed in Example 1.

Example 4.

An organic solar cell was manufactured in the same manner as in Example 1, except that the composite solution prepared in (1) was spin-coated at 1,300 rpm when the photoactive layer was formed in Example 1.

Comparative Example 1.

An organic solar cell was prepared in the same manner as in Example 1, except that the comparative compound prepared in Preparation Example 2 was used instead of Polymer 1-1 as the electron acceptor material in Example 1.

Comparative Example 2.

An organic solar cell was prepared in the same manner as in Comparative Example 1, except that the composite solution prepared in (1) was spin-coated at 900 rpm when the photoactive layer was formed in Comparative Example 1.

Comparative Example 3.

An organic solar cell was manufactured in the same manner as in Comparative Example 1, except that the composite solution prepared in (1) was spin-coated at 1,100 rpm when the photoactive layer was formed in Comparative Example 1.

Comparative Example 4.

An organic solar cell was manufactured in the same manner as in Comparative Example 1, except that the composite solution prepared in (1) was spin-coated at 1,300 rpm when the photoactive layer was formed in Comparative Example 1.

The photoelectric conversion characteristics of the organic solar cells prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were measured under the condition of 100 mW/cm ² (AM 1.5), and the results are shown in Table 1 below.

Spin-speed (rpm) V _oc
(V) J _sc
(mA/cm ² ) FF η
(%) mean η
(%) PBDB-T + Compound 1 Example
One 700 0.919 17.032 0.580 9.07 8.85 0.916 16.628 0.566 8.63 Example
2 900 0.925 17.168 0.629 9.98 10.07 0.924 17.202 0.639 10.16 Example
3 1,100 0.926 16.502 0.650 9.94 9.90 0.924 16.372 0.652 9.86 Example
4 1,300 0.910 16.053 0.644 9.40 9.09 0.901 15.766 0.618 8.78 PBDB-T + comparative compound 1 comparative example
One 700 0.739 17.869 0.523 6.91 6.91 0.736 17.932 0.522 6.90 comparative example
2 900 0.733 18.340 0.568 7.63 7.63 0.729 18.552 0.564 7.62 comparative example
3 1,100 0.750 17.323 0.605 7.86 7.87 0.746 17.627 0.598 7.87 comparative example
4 1,300 0.744 16.563 0.616 7.59 7.72 0.748 16.596 0.632 7.84

In Table 1, the Spin-speed is the rotational speed of the equipment when forming the photoactive layer by spin-coating the composite solution on the electron transport layer, V _OC is the open circuit voltage, J _SC is the short circuit current, and FF is the charging rate (Fill factor), η means 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 are, the higher the efficiency of the solar cell is. In addition, 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. The energy conversion efficiency (η) can be obtained by dividing the product of the open-circuit voltage (V _oc ), the short-circuit current (J _sc ), and the charge factor (FF) by the intensity of incident light (P _in ), and the higher the value, the better. .

Looking at the results of Table 1, the organic solar cells of Examples 1 to 4 using the polymer according to an exemplary embodiment of the present specification as an electron acceptor have an open circuit voltage compared to the organic solar cells of Comparative Examples 1 to 4 using a comparative compound. It can be seen that it is high, device efficiency such as charge factor is excellent, and energy conversion efficiency is excellent. Specifically, in the case of an organic solar cell using a polymer according to an exemplary embodiment of the present specification, energy conversion efficiency was measured to be 8% or more, preferably 9% or more. In addition, Figure 3 is a graph showing the UV-Vis absorption spectrum of the film state of the polymer 1-1 and the comparative compound, the polymer 1-1 according to an exemplary embodiment of the present specification has a red-shift compared to the comparative compound It can be seen that a trend has been observed. This tendency can be seen as a result of polymerization in the case of Polymer 1-1 as the length of the conjugated bond increases, and as a result, it can contribute to high FF and lead to excellent energy conversion efficiency.

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

Claims (11)

A polymer comprising a unit represented by Formula 1 below:
[Formula 1]

In Formula 1,
R1 to R10 are each hydrogen; A substituted or unsubstituted alkyl group; Or a substituted or unsubstituted alkoxy group,
At least one of R7 to R10 is a substituted or unsubstituted alkoxy group,
X1 and X2 are each hydrogen; halogen group; Or a substituted or unsubstituted alkyl group,
Ar is a substituted or unsubstituted divalent thiophene group; A substituted or unsubstituted divalent bithiophene group; A substituted or unsubstituted divalent thienothiophene group; Or a substituted or unsubstituted divalent dithienothiophene group,
p and q are each an integer of 0 to 3, and when p or q is 2 or more, they are the same as or different from each other. The method of claim 1,
Formula 1 is any one of the following formulas 2-1 to 2-4 polymer:
[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Formula 2-4]

In Formulas 2-1 to 2-4,
R1 to R10, X1, X2, p and q are the same as those defined in Formula 1 above,
R11 to R20 are each hydrogen or a halogen group. The method of claim 1,
Formula 1 is a polymer represented by Formula 3 below:
[Formula 3]

In Formula 3,
R5, R6, Ar, X1, X2, p and q are the same as defined in Formula 1 above,
R21 and R22 are each a substituted or unsubstituted alkyl group. The method of claim 1,
Formula 1 is a polymer represented by any one of Formulas 3-1 to 3-4:
[Formula 3-1]

[Formula 3-2]

[Formula 3-3]

[Formula 3-4]

In Chemical Formulas 3-1 to 3-4,
R5, R6, X1, X2, p and q are the same as defined in Formula 1 above,
R11 to R20 are each hydrogen or a halogen group,
R21 and R22 are each a substituted or unsubstituted alkyl group. The method of claim 4,
Wherein R11, R12, R18 and R19 are halogen groups. The method of claim 1,
Formula 1 is a polymer of any one selected from Formulas 1-1 to 1-6:
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Formula 1-6]

A composition for forming an organic active layer of an organic electronic device comprising the polymer according to any one of claims 1 to 6. The method of claim 7,
The polymer is a composition for forming an organic active layer of an organic electronic device containing 0.5wt% to 5wt% based on 100wt% of the composition. a first electrode;
a second electrode provided to face the first electrode; and
It is provided between the first electrode and the second electrode and includes one or more organic material layers including an organic active layer,
The organic active layer is an organic electronic device comprising the polymer according to any one of claims 1 to 6. The method of claim 9,
The organic active layer includes an electron donor and an electron acceptor,
The electron acceptor is an organic electronic device comprising the polymer. The method of claim 9,
The organic electronic device is an organic solar cell, an organic photoelectric device, an organic light emitting device, an organic photoreceptor, or an organic transistor.

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