KR20200027257A - Polymer and organic solar cell comprising the same - Google Patents

Abstract

The present specification provides a polymer including a unit represented by chemical formula 1 and an organic solar cell including the polymer. The polymer according to one embodiment of the present specification can freely adjust HOMO/LUMO energy levels.

Description

A polymer and an organic solar cell containing the same TECHNICAL FIELD

The present specification relates to polymers and organic solar cells comprising the same.

Organic solar cells are devices that can directly convert solar energy into electrical energy by applying the photovoltaic effect. Solar cells can be divided into inorganic solar cells and organic solar cells according to the material constituting the thin film. Typical solar cells are made of p-n junctions by doping crystalline silicon (Si), an inorganic semiconductor. Electrons and holes generated by absorbing light diffuse to the p-n junction and are accelerated by the electric field to move to the electrode. The power conversion efficiency of this process is defined as the ratio of the power given to the external circuit and the solar power entered into the solar cell, and has been achieved by up to 24% when measured under current standardized virtual solar irradiation conditions. However, since the conventional inorganic solar cell has already shown a limit in the economic and material supply and demand, the organic semiconductor solar cell, which is easy to process, inexpensive and has various functions, has been spotlighted as a long-term alternative energy source.

It is important to increase efficiency so that solar cells can output as much electrical energy as possible from solar energy. Conventional electron acceptor materials, such as low molecular materials (eg, ITIC), have low absorption in the long wavelength region and low thermal stability. There are such problems.

Accordingly, in recent years, many examples of organic solar cells using a polymer material as an electron acceptor material have been published, and research on compounds capable of various molecular designs and synthesis has been actively conducted.

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

The present specification provides a polymer and an organic solar cell comprising the same.

The present specification provides a polymer comprising a unit of Formula 1 below.

[Formula 1]

In Chemical Formula 1,

[D1] is a group that acts as an electron donor,

R1 to R4 are substituted or unsubstituted alkyl groups; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

R10 to R13 are the same as or different from each other, and each independently hydrogen; Halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group.

Another embodiment of the present specification is a first electrode;

A second electrode provided to face the first electrode; And

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

The organic layer provides an organic solar cell including the polymer.

The polymer according to the exemplary embodiment of the present specification can freely adjust the HOMO / LUMO energy level.

In addition, the polymer according to an exemplary embodiment of the present specification can control the charge balance when applied to an organic solar cell, and may exhibit excellent performance.

In addition, the polymer according to one embodiment of the present specification is capable of solution processing, which is advantageous for device application.

1 is a view showing an organic solar cell according to an exemplary embodiment of the present specification.
2 is a diagram showing the results of NMR measurement of Compound C.
3 is a view showing the results of UV measurement of polymer 1 and compound ITIC-Th.
4 is a view showing the photoelectric conversion characteristics of the organic solar cell prepared in Example 1 and Comparative Example 1.

Hereinafter, the present specification will be described in detail.

One embodiment of the specification provides a polymer comprising the unit of Formula 1 above.

The unit represented by Chemical Formula 1 can be polymerized by combining a short unit of [D1] with a thiophene-fused single molecule, and a wide absorption region due to a longer conjugation length of the molecule and Absorption of long wavelength regions is possible.

In Chemical Formula 1, [D1] is capable of binding to the meta or para position of a single molecule in which thiophene is fused.

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

In the present specification, when a member is said to be positioned “on” another member, this includes not only the case where one member is in contact with the other member but also another member between the two members.

In the present specification, “unit” refers to a repeating structure included in a polymer monomer, and refers to a structure in which the monomer is bonded to the copolymer by polymerization.

In the present specification, the meaning of “including units” is meant to be included in the main chain in the polymer.

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

는 상기 다른 단위 또는 치환기에 연결되는 부위를 의미한다.In this specification,

Means a site connected to the other unit or substituent.

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

The term "substitution" 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 to a position where the hydrogen atom is substituted, that is, a position where the substituent can be substituted, and when two or more are substituted , 2 or more substituents may be the same or different from each other.

As used herein, the term "substituted or unsubstituted" is deuterium; Halogen group; Alkyl groups; Cycloalkyl group; Alkoxy groups; Aryl group; Heterocyclic group; Imide group; Amide group; Carbonyl group; Ester groups; Alkenyl group; Silyl group; And one or more substituents selected from the group consisting of amine groups or having no substituents.

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

In the present specification, the alkyl group may be straight chain or branched chain, and carbon number is not particularly limited, but is preferably 1 to 30. Specific examples are methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl , Isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n -Heptyl, 1-methylhexyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, 5-methylhexyl, and the like, but is not limited thereto.

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

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

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

When the aryl group is a monocyclic aryl group, the number of carbon atoms is not particularly limited, but is preferably 6 to 30 carbon atoms. Specifically, the monocyclic aryl group may be a phenyl group, a biphenyl group, a terphenyl group, etc., 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 preferable that it has 10 to 30 carbon atoms. Specifically, the polycyclic aryl group may be a naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, peryllenyl group, chrysenyl group, fluorenyl group, and the like, but is not limited thereto.

In the present specification, the heterocyclic group includes one or more atoms other than carbon and heteroatoms, and specifically, the heteroatoms may include one or more atoms selected from the group consisting of O, N, Se, and S, and the like. The number of carbon atoms is not particularly limited, but preferably 2 to 30 carbon atoms, and the heterocyclic group may be monocyclic or polycyclic. Examples of the heterocyclic group include thiophene group, furanyl group, pyrrol group, imidazolyl group, thiazolyl group, oxazolyl group, oxadiazolyl group, pyridyl group, bipyridyl group, pyrimidyl group, triazinyl group, tria Jolyl group, acridil group, pyridazinyl group, pyrazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, phthalazinyl group, pyridopyrimidyl group, pyridopyrazinyl group, pyrazino pyrazinyl group , Isoquinolinyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, benzocarbazolyl group, benzothiophene group, dibenzothiophene group, benzofuranyl group, pe Nanthrolyl group (phenanthroline), thiazolyl group, isooxazolyl group, oxadiazolyl group, thiadiazolyl group, phenothiazinyl group, and dibenzofuranyl group, but are not limited thereto.

In this specification, the number of carbon atoms of the imide group is not particularly limited, but is preferably 1 to 30 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

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

In this specification, the number of carbon atoms of the carbonyl group is not particularly limited, but is preferably 1 to 30 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

In the present specification, the oxygen of the ester group may be substituted with an alkyl group having 1 to 25 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms. Specifically, it may be a compound of the following structural formula, but is not limited thereto.

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

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

In the present specification, the amine group is -NH ₂ ; Monoalkylamine groups; Dialkylamine groups; N-alkylarylamine group; Monoarylamine group; Diarylamine group; N-aryl heteroarylamine group; It may be selected from the group consisting of N-alkylheteroarylamine groups, monoheteroarylamine groups and diheteroarylamine groups, and the number of carbon atoms is not particularly limited, but is preferably 1 to 30. Specific examples of the amine group are methylamine group, dimethylamine group, ethylamine group, diethylamine group, phenylamine group, naphthylamine group, biphenylamine group, anthracenylamine group, and 9-methyl-anthracenylamine group , Diphenylamine group, ditolylamine group, N-phenyltolylamine group, triphenylamine group, N-phenylbiphenylamine group; N-phenyl naphthylamine group; N-biphenyl naphthylamine group; N-naphthylfluorenylamine group; N-phenylphenanthrenylamine group; N-biphenylphenanthrenylamine group; N-phenylfluorenylamine group; N-phenyl terphenylamine group; N-phenanthrenylfluorenylamine group; N-biphenyl fluorenylamine group and the like, but is not limited thereto.

In one embodiment of the present specification, [D1] is any one of the following structures.

In the above structure,

X1 to X8 are the same as or different from each other, and each independently CRR ', NR, O, SiRR', PR, S, GeRR ', Se or Te,

R20 to R29, R and R 'are the same as or different from each other, and each independently hydrogen; Halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group.

In one embodiment of the present specification, [D1] 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 dithienothiophene group.

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

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

In Chemical Formulas 1-1 to 1-4,

X1 to X8 are the same as or different from each other, and each independently CRR ', NR, O, SiRR', PR, S, GeRR ', Se or Te,

R1 to R4 are substituted or unsubstituted alkyl groups; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,

R10 to R13, R20 to R29, R and R 'are the same as or different from each other, and each independently hydrogen; Halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group.

In one embodiment of the present specification, X1 to X8 are the same as or different from each other, and each independently, NR, O, or S.

In one embodiment of the present specification, X1 to X8 are each S.

In one embodiment of the present specification, R1 to R4 are the same as or different from each other, and each independently a substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group.

In one embodiment of the present specification, R1 to R4 are the same as or different from each other, and each independently a substituted or unsubstituted phenyl group; Or a substituted or unsubstituted thiophene group.

In one embodiment of the present specification, R1 to R4 are the same as or different from each other, and each independently an phenyl group unsubstituted or substituted with an alkyl group; Or a thiophene group unsubstituted or substituted with an alkyl group.

In one embodiment of the present specification, R1 to R4 are the same as each other, and each is a phenyl group substituted with an alkyl group.

In one embodiment of the present specification, R1 to R4 are the same as each other, and each is a thiophene group substituted with an alkyl group.

In one embodiment of the present specification, Chemical Formula 1 includes any one of the following structures.

In one embodiment of the present specification, the polymer includes 2 to 10,000 units represented by Chemical Formula 1.

In one embodiment of the present specification, the polymer has a maximum absorption wavelength at 300 nm to 850 nm, preferably at 500 nm to 750 nm.

Accordingly, when applied to a solar cell, since light absorption is possible in two or more of the green, red, and blue areas, the efficiency of the solar cell is improved.

In one embodiment of the present specification, the compound absorbs light in the green and red regions.

In one embodiment of the present specification, the green region has a maximum emission wavelength of 500 nm to 570 nm, the red region has a maximum emission wavelength of 630 nm to 780 nm, and the blue region has a maximum emission wavelength of 400 nm to 480 nm It can mean something in between.

In one embodiment of the present specification, the compound is capable of absorbing light in the green and red regions, and can also absorb light in the infrared region. For example, it is possible to absorb not only the wavelength range of 500 nm to 780 nm, but also light in a region of 780 nm or more. Accordingly, when applied to an organic solar cell, the absorption wavelength range of the organic solar cell can exhibit a wide effect.

An exemplary embodiment of the present specification is a first electrode;

A second electrode provided to face the first electrode; And

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

The photoactive layer provides an organic solar cell comprising the polymer.

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

The electron acceptor includes the polymer.

In one embodiment of the present specification, the description of the compound is the same as described above.

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 (thiophen-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)]), PBDB-T (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) )]), PEC10 and PBDBT (poly (benzodithiophene-benzotriazole)).

In one embodiment of the present specification, the electron donor and the electron acceptor may be mixed in a ratio of 1:10 to 10: 1. Specifically, the electron donor and the electron acceptor may be mixed in a mass ratio of 1: 2 to 5: 1, and more specifically, the electron donor and electron acceptor may be mixed in a mass ratio of 1: 2 to 2: 1. If necessary, the electron donor and electron acceptor may be mixed in a mass ratio of 1: 1.

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

The bulk heterojunction means that the electron donor material and the electron acceptor material are mixed with each other in the photoactive layer.

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

The organic solar cell according to the exemplary embodiment of the present specification includes a first electrode, a photoactive layer, and a second electrode.

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

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

In one embodiment of the present specification, the 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.

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

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

In one embodiment of the present specification, a passivation layer may be further included on the second electrode.

The passivation layer may be formed on the exposed surface of the organic solar cell, and may absorb shock and stress generated when removing the substrate, as well as protecting the organic solar cell.

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

In one embodiment of the present specification, the organic solar cell may be used without limiting materials and / or methods in the art except for using the compound as a photoactive 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, handling ease, and waterproofness, but is not limited thereto, and is limited if it is a substrate commonly used in organic solar cells. Does not work. Specifically, there are glass or polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), polyimide (PI), and triacetyl cellulose (TAC). It is not limited to this.

The material of the first electrode may be a material that is transparent and has excellent conductivity, but is not limited thereto. Metals such as vanadium, chromium, copper, zinc, gold or alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); A combination of metal and oxide such as ZnO: Al or SnO2: Sb; And conductive polymers such as poly (3-methylthiophene), poly [3,4- (ethylene-1,2-dioxy) thiophene] (PEDOT), polypyrrole and polyaniline, but is not limited thereto. .

The method for forming the first electrode is not particularly limited, but, for example, sputtering, E-beam, thermal deposition, 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, water removal, and hydrophilic modification processes.

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

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

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

One of the above methods can be selected according to the state of the first electrode or the substrate. However, in any method, it is desirable to prevent oxygen desorption on the surface of the first electrode or the substrate in common and to suppress the residual of moisture and organic matter as much as possible. At this time, the substantial effect of the pretreatment can be maximized.

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

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

The second 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, LiF / Al, LiO ₂ / Al, LiF / Fe, Al: Li, Al: BaF ₂ , or Al: BaF ₂ : Ba may be a material having a multilayer structure, but is not limited thereto.

The second 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 passivation layer may be made of an inorganic material such as a silicon oxide film (SiOx) and a silicon nitride film (SiNx), or an organic material such as benzocyclobutene (BCB) and photoacryl, but is not limited thereto.

The passivation layer may be formed on the exposed surface of the organic solar cell by using plasma enhanced chemical vapor deposition (PECVD).

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

Materials applied to the hole transport layer include PEDOT: PSS (Poly (3,4-ethylenediocythiophene) doped with poly (styrenesulfonic acid)), molybdenum oxide (MoOx); Vanadium oxide (V ₂ O ₅ ); Nickel oxide (NiO); And tungsten oxide (WO _x ) and the like, but is not limited thereto.

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

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

Manufacturing example  1. Preparation of Polymer 1

(1) Preparation of compound C

Compound A (340 mg, 0.3 mmol) and Compound B (340 mg, 0.9 mmol) were dissolved in 50 mL chloroform (CHCl ₃ ). Then, 2 mL of pyridine was injected and refluxed at 70 ° C. for 8 hours. The reaction mixture was purified by column chromatography on silica gel (dichloromethane / n-hexane (1: 1)) and recrystallized from dichloromethane / methanol. Then, it dried under vacuum to obtain 490 mg of Compound C. (Yield 98%)

2 is a diagram showing the results of NMR measurement of Compound C.

(2) Preparation of polymer 1

Compound C (393 mg, 0.24 mmol), 2,5-bis (trimethylsterenyl) thiophene (100 mg, 0.24 mmol), tetrakis (triphenylphosphine) palladium (0) (Pd (PPh ₃ ) ₄ ) ( 14 mg, 0.01 mmol) was dissolved in 15 mL of degassed toluene and the resulting reaction mixture was refluxed at 100 ° C. for 12 hours under nitrogen conditions. The reaction mixture was cooled and precipitated in 100 mL of methanol. The polymer was collected by filtration and washed with methanol to give a solid. The polymer was treated with sequential Soxhlet extraction with acetone, hexane, and chloroform. The chloroform fraction was concentrated in vacuo, precipitated in methanol and collected by filtration to obtain polymer 1 in solid form.

UV results of the polymer 1 and the compound ITIC-Th prepared above are shown in FIG. 3.

From FIG. 3, it can be confirmed that as the conjugation length is longer when the polymer 1 is compared to the ITIC-Th single molecule, light absorption in a wide area is possible and absorption is extended to a long wavelength area.

Example  One.

Compound 1 prepared in Preparation Example 1 was used as an electron acceptor, and the following PEC10 was used as an electron donor to dissolve in chlorobenzene (CB) at a ratio of 1.5: 1 to prepare a composite solution. At this time, the concentration was adjusted to 2.0 wt%, and the organic solar cell had a structure of ITO / ZnO / photoactive layer / MoO ₃ / Ag.

[PEC10]

The glass substrate coated with ITO was ultrasonically cleaned using distilled water, acetone, and 2-propanol, ozonized the ITO surface for 10 minutes, and then spin-coated the ZnO precursor solution at a rate of 4000 rpm for 40 seconds for 10 minutes at 80 ° C. An electron transport layer was formed by heat treatment.

Then, the composite solution was filtered through a 0.45 μm PP syringe filter, spin-coated at 800 rpm for 15 seconds, and heat-treated at 135 ° C. for 10 minutes to form a photoactive layer.

In the thermal evaporator, MoO ₃ was deposited on the photoactive layer to a thickness of 10 nm at a rate of 0.2 Pa / s to prepare a hole transport layer.

Thereafter, Ag was deposited on the hole transport layer at a thickness of 100 nm at a rate of 1 kPa / s inside the thermal evaporator to prepare an organic solar cell.

Example  2.

Compound 1 prepared in Preparation Example 1 was used as an electron acceptor, and PEC10 was used as an electron donor to dissolve in chlorobenzene (CB) at a ratio of 1.5: 1 to prepare a composite solution. At this time, the concentration was adjusted to 2.0 wt%, and the organic solar cell had a structure of ITO / ZnO / photoactive layer / MoO ₃ / Ag.

The glass substrate coated with ITO was ultrasonically cleaned using distilled water, acetone, and 2-propanol, ozonized the ITO surface for 10 minutes, and then spin-coated the ZnO precursor solution at a rate of 4000 rpm for 40 seconds for 10 minutes at 80 ° C. An electron transport layer was formed by heat treatment.

Thereafter, the composite solution was filtered with a 0.45 μm PP syringe filter, spin-coated at 1000 rpm for 15 seconds, and heat-treated at 135 ° C. for 10 minutes to form a photoactive layer.

In the thermal evaporator, MoO ₃ was deposited on the photoactive layer to a thickness of 10 nm at a rate of 0.2 Pa / s to prepare a hole transport layer.

Thereafter, Ag was deposited on the hole transport layer at a thickness of 100 nm at a rate of 1 kPa / s inside the thermal evaporator to prepare an organic solar cell.

Comparative example  One.

In Example 1, an organic solar cell was manufactured in the same manner as in Example 1, except that ITIC-Th having the following structure was used instead of Compound 1 when preparing the composite solution.

Comparative example  2.

In Example 2, an organic solar cell was manufactured in the same manner as in Example 1, except that ITIC-Th of the above structure was used instead of Compound 1 when preparing the composite solution.

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

Voc
(V) Jsc
(mA / cm ² ) FF η
(%) Mean η
(%) Example 1 0.858 7.155 0.450 2.76 2.71 0.852 7.274 0.428 2.65 Example 2 0.702 6.360 0.348 1.55 1.77 0.798 6.430 0.388 1.99 Comparative Example 1 0.760 1.376 0.382 0.40 0.41 0.776 1.433 0.375 0.42 Comparative Example 2 0.695 1.373 0.358 0.34 0.34 0.665 1.514 0.336 0.34

In Table 1, Voc is the open voltage, Jsc is the short-circuit current, FF is the fill factor, and η is the energy conversion efficiency. The open voltage and short-circuit current are the X-axis and Y-axis intercepts in the quadrant of the voltage-current density curve, respectively. The higher these two values, the higher the efficiency of the solar cell is. In addition, the fill factor is a value obtained by dividing the area of the rectangle that can be drawn inside the curve by the product of the short-circuit current and the open voltage. The energy conversion efficiency can be obtained by dividing these three values by the intensity of the irradiated light. The higher the value, the better.

From Table 1, it can be seen that the organic solar cell incorporating the polymer according to one embodiment of the present specification has superior performance compared to the organic solar cell incorporating the conventional ITIC-Th.

10: Substrate
20: first electrode
30: electron transport layer
40: photoactive layer
50: hole transport layer
60: second electrode

Claims (8)

Polymer comprising a unit represented by the formula (1):
[Formula 1]

In Chemical Formula 1,
[D1] is a group that acts as an electron donor,
R1 to R4 are substituted or unsubstituted alkyl groups; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,
R10 to R13 are the same as or different from each other, and each independently hydrogen; Halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group. The method according to claim 1,
[D1] is a polymer of any one of the following structures:

In the above structure,
X1 to X8 are the same as or different from each other, and each independently CRR ', NR, O, SiRR', PR, S, GeRR ', Se or Te,
R20 to R29, R and R 'are the same as or different from each other, and each independently hydrogen; Halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group. Following claim 1,
[D1] 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 dithienothiophene polymer. The method according to claim 1,
The Formula 1 is a polymer represented by any one of the following Formulas 1-1 to 1-4:
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

In Chemical Formulas 1-1 to 1-4,
X1 to X8 are the same as or different from each other, and each independently CRR ', NR, O, SiRR', PR, S, GeRR ', Se or Te,
R1 to R4 are substituted or unsubstituted alkyl groups; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,
R10 to R13, R20 to R29, R and R 'are the same as or different from each other, and each independently hydrogen; Halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroring group. The method according to claim 1,
Formula 1 is a polymer comprising any one of the following structures:

A first electrode;
A second electrode provided to face the first electrode; And
At least one organic material layer provided between the first electrode and the second electrode, including a photoactive layer,
At least one layer of the organic layer is an organic solar cell comprising the polymer according to any one of claims 1 to 5. The method according to claim 6,
The photoactive layer includes an electron donor and an electron acceptor,
The electron acceptor is an organic solar cell comprising the polymer. The method according to claim 5,
The organic solar cell further comprises one or more organic material layers selected from the group consisting of a hole injection layer, a hole transport layer, a hole blocking layer, a charge generating layer, an electron blocking layer, an electron injection layer and an electron transport layer. .

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