KR101833215B1 - Organic semiconducting compounds, manufacturing method thereof, and organic electronic device containing the same - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a compound that exhibits the highest light-to-electricity conversion efficiency in an organic semiconductor compound of an organic solar cell having an excellent electric characteristic and a large-area sub-module organic solar cell device, a method for producing the same, and an organic electronic device containing the same .

Description

TECHNICAL FIELD The present invention relates to an organic semiconductor compound, a method for producing the same, and an organic electronic device including the organic semiconductor compound.

The present invention relates to an organic semiconductor compound, a method for producing the organic semiconductor compound, and an organic electronic device including the organic semiconductor compound, and more particularly, to an organic semiconductor compound containing thiophene-vinylene having a novel fluorine, Device. The organic semiconductor compound of the present invention is a high-performance organic semiconductor compound suitable for a high-efficiency unit cell and a large-area module solar cell device.

In 2009, the photovoltaic industry has installed more than 6GW in the world, forming an independent industrial country of $ 30 billion market, and it is expected to continue to grow rapidly until mid-21st century.

Current major products are crystalline silicon solar cells, which have overwhelming use in the solar power market. In recent years, however, market share of inorganic thin film solar cells such as a-Si, CdTe and CIGS has been steadily increasing. Respectively. In addition, organic solar cells represented by dye-sensitized and organic thin-film type are not yet entering the market in earnest, but they can lead the ubiquitous solar era, which is expected in the future by promoting cheap material cost, process cost, and light, Another possibility is presented. However, if the efficiency is higher than 10% in the future, it will be used for building integrated photovoltaic system (BIPV), which creates a beautiful appearance by installing it on a window or a balcony of a building It is expected to be largely written on. In the future, it is expected to serve as a diverse energy source supporting various flexible displays, military, indoor, and disposable solar cells.

In 1986, Eastman Kodak's CW Tang produced copper phthalocyanine (CuPc) and perylenetetracarboxylic acid (CuPc) in 1986. However, in the 1970s when the possibility of organic solar cells was first suggested, efficiency was too low to be practical. (perylene tetracarboxylic acid) derivatives, the interest and research on organic solar cell have been rapidly increasing and the development has been made. In 1995, Yu and Yu introduced the concept of bulk-heterojunction (BHJ). Fullerene derivatives such as PCBM, which have improved solubility, have been developed as n-type semiconductor materials. there was.

In particular, the research of organic solar cells has rapidly increased since 2000, and polymer solar cells capable of introducing photoactive by a solution process have introduced a bulk-hetero junction concept with PCBM in the early 2000s, By using P3HT as a photoactive layer, efficiency of 4 ~ 6% has been generally obtained. As a result, attempts to develop new materials and device structures by attracting attention from academia and industry have been made since 2005 It started in earnest.

In the case of polymer solar cells, improvement of efficiency is prominent due to new device configuration and process conditions change. In order to replace existing materials, donor materials with low bandgap and high charge mobility The development of new acceptor materials continues to require research and development. To date, organic solar cell materials have reported efficiencies of up to 10%. However, in order to commercialize organic solar cells, it is necessary to make large-area solar cell devices. However, the currently reported high efficiency organic solar cell materials have a photoactive layer area of 0.1 cm ² , which makes commercialization difficult.

Also, as the area of the photoactive layer is widened, the efficiency is lowered and the conventional photoactive material suffers difficulties. In addition, the photoactive materials of organic solar cells, which have been reported to date, exhibit excellent performance in very thin films of less than 100 nm. For commercialization, it is necessary to use roll-to-roll process, slot-die printing, and ink-jet printing. Thin film is difficult to commercialize.

In other words, for the commercialization of organic solar cells, it is urgent to develop materials that exhibit excellent efficiency in a photoactive layer of a thick thickness (about 200 nm or more) and excellent efficiency in a large area.

Korean Patent Publication No. 10-2013-0069445 Korean Patent Publication No. 10-2014-0125924

Nature Commun. 5, 5293 (2014)

The present invention provides an organic semiconductor compound containing thiophene-vinylene having fluorine as a high-performance organic material optimized for a large-area submodule organic solar cell.

The present invention also provides a method for producing the organic semiconductor compound of the present invention.

The present invention also provides an organic electronic device containing the organic semiconductor compound of the present invention.

The present invention also provides a unit cell containing the organic semiconductor compound of the present invention and a stacked-area submodule organic solar cell device.

The present invention provides an organic semiconducting compound capable of exhibiting excellent performance in a large-area submodule solar cell directly related to commercialization, and it is an object of the present invention to provide an organic semiconducting compound of an organic solar cell that exhibits the world's highest efficiency in a large- And more particularly to an organic semiconductor compound containing thiophene-vinylene having fluorine.

The organic semiconductor compound of the present invention is represented by the following Formula 1:

[Chemical Formula 1]

[In the above formula (1)

A is C ₆ -C ₃₀ arylene or C ₃ -C ₃₀ heteroarylene;

The arylene and heteroarylene of A may be substituted by one or more substituents selected from the group consisting of C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy, C ₁ -C ₃₀ alkylthio, C ₃ -C ₃₀ cycloalkyl, C ₁ -C ₃₀ alkoxy C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy C ₆ -C ₃₀ aryl, C ₃ -C ₃₀ heteroaryl, C ₃ -C ₃₀ heteroaryl Which may be further substituted with one or more substituents selected from the group consisting of aryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkyl C ₃ -C ₃₀ heteroaryl and C ₁ -C ₃₀ alkoxy C ₃ -C ₃₀ heteroaryl, ;

n is an integer from 1 to 2000;

Wherein said heteroaryl and heteroarylene comprise at least one heteroatom selected from N, O and S.

The organic semiconductor compound of the present invention is produced by copolymerizing thiophene-vinylene having electron donor fluorine with various electron acceptors (represented by A in Chemical Formula 1) to form a unit cell organic electronic device, specifically, a large-area (6600 mm ² ) And can be used for solar cell devices.

In particular, the organic semiconductor compound of the present invention has a high crystallinity as well as a lowering of the HOMO energy level by introducing fluorine atoms into the molecule, and can realize improved hole and electron mobility and nano structure In addition to exhibiting the world's best performance in the unit cell organic solar cell device using the same, it achieved the world's best performance in the large-area sub-module organic solar cell device.

Substituents comprising " alkyl ", " alkoxy " and other " alkyl " moieties described in the present invention include both straight chain and branched forms.

&Quot; Aryl ", as used herein, refers to an organic radical derived from an aromatic hydrocarbon by the removal of one hydrogen, with a single or fused ring containing in each ring suitably 4 to 7, preferably 5 or 6 ring atoms . Specific examples include, but are not limited to, phenyl, naphthyl, biphenyl, anthryl, fluorenyl, phenanthryl, triphenylenyl, pyreneyl, perylenyle, klycenyl, naphthacenyl, fluoranthenyl and the like.

&Quot; Heteroaryl " in the present invention means an aryl group having 1 to 4 hetero atoms selected from N, O and S as the aromatic ring skeletal atoms and the remaining aromatic skeletal atom carbon, Monocyclic heteroaryl, and condensed polycyclic heteroaryl with one or more benzene rings. The heteroaryl in the present invention also includes a form in which one or more heteroaryl is connected to a single bond. Specific examples thereof include monocyclic heteroaryl such as furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, isoxazolyl, oxazolyl and pyridyl, benzofuranyl, dibenzofuranyl, Examples of the polycyclic heterocycle such as benzothiophenyl, benzothiophenyl, isobenzofuranyl, benzoimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, quinolyl, isoquinolyl, Aryl, and the like.

In the organic semiconductor compound of Formula 1 according to an embodiment of the present invention, A may be C ₃ -C ₃₀ heteroarylene, preferably one or more heteroarylene selected from the following structures:

[Wherein X ¹ and X ² are each independently O or S;

R ^1, R ^2, R ⁵ and R ⁶ are each independently hydrogen, C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy, C ₁ -C ₃₀ alkylthio, C ₃ -C ₃₀ cycloalkyl, C ₁ - C ₃₀ alkoxycarbonyl C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy C ₆ -C ₃₀ aryl, C ₃ -C ₃₀ heteroaryl, , C ₃ -C ₃₀ heteroaryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkyl C ₃ -C ₃₀ heteroaryl or C ₁ -C ₃₀ alkoxy C ₃ -C ₃₀ heteroaryl;

R ³ and R ⁴ are each independently hydrogen or halogen.

In the organic semiconductor compound of Formula 1 according to an embodiment of the present invention, the organic semiconductor compound may be represented by Formula 2 below.

(2)

[In the formula (2)

R ¹ and R ² are each independently selected from the group consisting of hydrogen, C ₁ -C ₃₀ alkyl, C ₃ -C ₃₀ cycloalkyl, C ₁ -C ₃₀ alkoxy C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ Alkyl or C ₃ -C ₃₀ heteroaryl C ₁ -C ₃₀ alkyl;

R ³ and R ⁴ are each independently hydrogen or fluorine;

and n is an integer of 1 to 2000.]

일 수 있으며, 여기서 a는 1 내지 5의 정수이고, R은 분지쇄의 C₉-C₂₀알킬일 수 있다.In the organic semiconductor compound of Formula 2 according to an embodiment of the present invention, R ¹ and R ² are each independently a C ₁ to C _{6 group} in order to have high charge mobility and high electron density and high solubility in an organic solvent. may be -C ₃₀ alkyl, preferably C ₆ -C ₃₀ alkyl may be, more preferably C ₈ -C ₂₅ alkyl may be, more preferably, R ¹ and R ² than are, each independently

Where a is an integer from 1 to 5 and R may be branched C ₉ -C ₂₀ alkyl.

In one embodiment of the present invention, the organic semiconductor compound of the present invention may be selected from the following structures, but is not limited thereto.

And n is an integer of 1 to 2000.

The present invention also provides a method for preparing an organic semiconductor compound represented by Formula 1 by copolymerizing a tin compound represented by Formula 3 and a halide derivative represented by Formula 4 below.

(3)

[Chemical Formula 4]

[In the above formulas (3) and (4)

A is C ₆ -C ₃₀ arylene or C ₃ -C ₃₀ heteroarylene and the arylene and heteroarylene of A are selected from the group consisting of C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy, C ₁ -C ₃₀ alkyl alkylthio, C ₃ -C ₃₀ cycloalkyl, C ₁ -C ₃₀ alkoxy C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy C ₆ -C ₃₀ aryl, C ₃ -C ₃₀ heteroaryl, C ₃ -C ₃₀ heteroaryl, C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkyl, C ₃ -C ₃₀ heteroaryl and C ₁ -C ₃₀ alkoxy C ₃ It may further be substituted by one or more substituents selected from the group consisting of -C ₃₀ heteroaryl, and;

Y is halogen;

n is an integer from 1 to 2000;

Wherein said heteroaryl and heteroarylene comprise at least one heteroatom selected from N, O and S.

The tin compound of Formula 3 and the halide derivative of Formula 4 may be prepared by a conventional method known to those skilled in the art.

The present invention also provides an organic electronic device comprising the organic semiconductor compound of the present invention, particularly an organic thin film transistor or an organic solar cell. More specifically, the present invention provides an organic electronic device containing the organic semiconductor compound of the present invention in a photoactive layer.

The organic electronic device of the present invention can be any conventional organic electronic device that a person skilled in the art can recognize. Generally, an organic solar cell is a metal-organic semiconductor (a photoactive layer) / metal (MSM, MIM) structure. ITO (Indium Tin Oxide), which has a high work function and is a transparent electrode, is used as a cathode, and Ag or MoO ₃ having a high work function is used as a cathode.

In particular, a BHJ (Bulk Hetero Junction) structure in which an organic semiconductor compound / C60 or an organic semiconductor compound / C70 composite is used as an electron donor and an electron acceptor as an organic semiconductor will be described as an example.

First, the organic semiconductor compound / C60 composite solution, which is a photoactive layer, is coated on the ITO layer to a thickness of about 200 nm by spin coating, inkjet printing or the like. An Ag or MoO3 metal is vacuum deposited on the electrode and used as a cathode. If necessary, an exciton blocking layer (EBL) may be inserted between the electrode and the photoactive layer to improve the lifetime of the charge. As the EBL layer, a mixture of ZnO can be used.

In general, the diffusion distance of excitons in organic donor materials is about 10-30 nm, which is much shorter than the appropriate thickness (over 100 nm) of electron donor materials for solar absorption. This is one of the fundamental reasons for limiting the efficiency of organic solar cells. However, it is difficult to solve such a problem with the conventional bi-layer structure. In addition, since the two materials forming the BL (bi-layer) structure are organic monomolecules, it is necessary to deposit them. In the case of the polymer, it is difficult to manufacture by a simple process such as spin coating. On the other hand, since the polymer BHJ structure uses a mixture of electron donor (D) and electron acceptor (A) materials, the manufacturing process is simple and the surface area of the D / A (donor / And the charge collection efficiency as an electrode is also increased.

In this respect, the organic solar cell according to the present invention is preferably a BHJ structure, and an organic semiconductor compound according to the present invention is used as an electron-donating material and at least one selected from the following electron- .

Among the above electron-accepting materials, it is more preferable to use materials such as PCBM and PCBCR, which are designed to dissolve well in an organic solvent, but the present invention is not limited thereto.

In particular, the large-area sub-module organic solar cell device manufactured by the present invention was fabricated through a slot-die coating method, and all layers except for the electrode were formed by a solution process. The production of a detailed laminated organic solar cell element is described in the Examples.

The organic semiconductor compound of the present invention has a structure copolymerized with a thiophenvinylene novel electron donor having fluorine and various electron acceptors (represented by A in the formula (1)), exhibits excellent crystallinity due to the introduction of fluorine, Electron mobility, and nano structure. In particular, such structure formation exhibits very good properties in a thick photoactive layer thickness. This is very advantageous for equipment such as roll-to-roll, ink-jet printing to produce large area sub-modules for commercialization.

Also, in the present invention, a large-area submodule organic solar cell was manufactured using a material exhibiting excellent performance in a unit cell, and the world's highest photoelectric conversion efficiency could be achieved. This indicates that the material is a photoactive material highly advantageous for commercialization of an organic solar cell .

Therefore, the organic semiconductor compound of the present invention is an organophosphorous compound containing a fluorine-containing thiophene-vinylene as an electron acceptor and is copolymerized with various electron acceptors to exhibit excellent photoelectric conversion efficiency even in a thick photoactive layer, Exhibits the world's best photoelectric conversion efficiency in organic solar cell devices.

Further, since the present invention has been developed as a new donor material and can increase the maximum energy conversion efficiency of existing organic solar cells and is advantageous for commercialization rather than actual laboratory scale, (breakthrough).

The present invention also provides a method for producing an organic semiconductor compound having high electrical properties.

FIG. 1 shows the thermal stability (TGA) results of Polymers 1 and 2 prepared in Examples 1 and 2. FIG.
2 is a UV spectrum of a solution state of Polymers 1 and 2 prepared in Examples 1 and 2. FIG.
3 is a UV spectrum of the film state of Polymers 1 and 2 prepared in Examples 1 and 2. FIG.
4 is a JV characteristic curve of the unit cell organic solar cell fabricated in Examples 3 and 4.
FIG. 5 shows the results of measurement of external quantum efficiency of the unit cell organic solar cell fabricated in Examples 3 and 4. FIG.
FIG. 6 is a two-dimensional grazing-incidence X-ray diffraction (2D-GIXD) image of Polymers 1 and 2 prepared in Examples 1 and 2. FIG.
FIG. 7 is a schematic diagram of a large-area sub-module organic solar cell actually manufactured (left) and a JV characteristic curve of the large-area sub-module organic solar cell manufactured in Example 5 (right).

Hereinafter, the present invention will be described in detail by way of examples. However, the following Preparation Examples and Examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Here, unless otherwise defined in the technical terms and the scientific terms used, those having ordinary skill in the art to which the present invention belongs have the same meaning as commonly understood by those skilled in the art. Repeated descriptions of the same technical constitution and operation as those of the conventional art will be omitted.

Example

All reagents required for synthesis were purchased from Junsei, Aldrich, Alpha and Tixia. Silicagel was purchased from Merck and Chloroform, Hexane, Methanol, and Acetone for HPLC used in the purification process were purchased from JT Baker. Respectively.

The electron donor material used in the present invention, 4,7-bis (5-bromo-4- (2-octyldodecyl) thiophen-2-yl) benzo [c] [1,2,5] thiadiazole And 4,7-bis (5-bromo-4- (2-octyldodecyl) thiophen-2-yl) -5,6-difluorobenzo [c] [1,2,5] thiadiazole Was synthesized by a reported paper (Nature Commun. 5, 5293 (2014)).

UV in the film state was measured by filtration using a 0.45 μm syringe filter before measurement and spin coating. PCBM ([6,6] -phenyl C71-butyric acid methyl ester) was used as an electron acceptor material of the organic solar cell device. ^{The 1} H NMR spectrum was measured with a Varian Mercury Plus 300 MHz spectrometer and the ultraviolet absorption spectrum was measured with JASCO JP / V-570. Cyclic voltammetry was measured using a CH Instruments Electrochemical Analyzer to determine the HOMO level of the material and the JV curve of the solar cell was measured using a 1Kw solar simulator (Newport 91192) Respectively. The IPCE characteristics were measured by Solar cell response / Quantum efficiency / IPCE measurement system (PV Measurements, Inc.).

Production Example 1 Production of (E) -1,2-bis (3-fluoro-5- (trimethylstannyl) thiophen-2-yl) ethane (compound ffTVT)

Preparation of (E) -1,2-bis (3-bromothiophen-2-yl) ethane (Compound 1)

A 500 mL round flask was vacuumed with 3-bromothiophene-2-carbaldehyde (14 g, 73.2 mmol). After THF (100 mL) was added, TiCl ₄ (12.07 mL, 109.8 mmol) was slowly added at -18 ° C. After 30 minutes, Zn powder (15 g, 219.6 mmol) was slowly added thereto, stirred at room temperature for 30 minutes, and refluxed at 50 ° C for 4 hours. After completion of the reaction, the mixture was quenched through distilled water (100 mL), the organic layer was extracted with chloroform and brine, and the remaining water was removed with anhydrous magnesium sulfate, and pure compound 1 was obtained by column chromatography. Yield: 39% (10 g) of clear E isomer was obtained.

^{1 H NMR (300 MHz, CDCl} 3, ppm): δ 7.20 (d, 2H), 7.12 (s, 2H), 6.98 (d, 2H)

¹³ C NMR (75 MHz, CDCl ₃ , ppm):? 132.5, 132.0, 128.2, 124.0, 110.1.

Preparation of (E) -1,2-bis (3-bromo-5- (trimethylsilyl) thiophen-

A 500 mL round flask was vacuumed with compound 1 (10.0 g, 28.56 mmol). After injecting diethyl ether (200 mL), LDA was slowly injected at -78 ° C. After that, trimethylsilane chloride (7.6 mL, 59.97 mmol) was poured at the same temperature and stirred at room temperature for 12 hours. After completion of the reaction, the reaction mixture was quenched through distilled water (100 mL), the organic layer was extracted with ethyl acetate and brine, and the remaining water was removed with anhydrous magnesium sulfate, and pure compound 2 was obtained by column chromatography.

Yield: 76% (10.8 g)

^{1 H NMR (300 MHz, CDCl} 3, ppm): δ 7.13 (s, 2H), 7.06 (s, 2H), 0.32 (s, 18H)

¹³ C NMR (75 MHz, CDCl ₃ , ppm):? 138.5, 137.6, 135.3, 125.3, 111.4. -0.91.

Preparation of (E) -1,2-bis (3-fluoro-5- (trimethylsilyl) thiophen-

A 500 mL round flask was vacuumed with compound 2 (10.0 g, 20.22 mmol). After injecting THF (200 mL), n-BuLi was slowly injected at -78 ° C. Then, N-fluorobenzenesulfonimide ((PhSO ₂ ) ₂ NF) (19.1 g, 60.66 mmol) was introduced at the same temperature and stirred at room temperature for 12 hours. After completion of the reaction, quenching was carried out with 100 mL of distilled water. The organic layer was extracted with ethyl acetate and brine, and the remaining water was removed with anhydrous magnesium sulfate, and pure compound 3 was obtained by column chromatography.

Yield: 79% (6.1 g)

^{1 H NMR (300 MHz, CDCl} 3, ppm): δ 6.92 (s, 2H), 6.88 (s, 2H), 0.31 (s, 18H).

¹³ C NMR (75 MHz, CDCl ₃ , ppm):? 140.8, 138.3, 137.1, 132.6, 115.3. -0.88.

(E) -1,2- Bis (3-fluoro-thiophen-2-yl) ethane  (compound 4) of  Produce

Trifluoroacetic acid (30 mL) and chloroform (30 mL) were poured into Compound (3) (3.0 g, 8.05 mmol) in a 250 mL round flask and stirred at room temperature for 5 hours. After completion of the reaction, the reaction mixture was quenched through distilled water (50 mL), and the organic layer was extracted with chloroform and brine. The residual water was removed with anhydrous magnesium sulfate, and pure compound 4 was obtained by column chromatography.

Yield: 80% (2.3 g)

^{1 H NMR (300 MHz, CDCl} 3, ppm): δ 6.90 (d, 2H), 6.88 (s, 2H), 6.85 (d, 2H).

¹³ C NMR (75 MHz, CDCl ₃ , ppm):? 141.2, 139.8, 137.6, 135.8, 121.1.

Preparation of (E) -1,2-bis (3-fluoro-5- (trimethylstannyl) thiophen-2- yl) ethane (compound ffTVT)

After injecting 100 mL of THF and LDA into a 100 mL round flask, 4 (1.0 g, 4.38 mmol) prepared at -78 ° C was slowly injected. Thereafter, 13.14 mL of trimethyltin chloride (1 M in hexanes) was slowly injected, followed by stirring at room temperature for 2 hours. When the reaction was completed, quenching was carried out with distilled water (50 mL). The organic layer was extracted with chloroform and brine, and the remaining water was removed with anhydrous magnesium sulfate, and pure compound ffTVT was obtained by recrystallization.

Yield: 49% (1.2 g)

^{1 H NMR (300 MHz, CDCl} 3, ppm): δ 6.87 (s, 2H), 6.82 (s, 2H), 0.37 (s, 18H).

¹³ C NMR (75 MHz, CDCl ₃ , ppm):? 148.9, 147.6, 143.2, 140.7, 128.4, -8.28.

Anal. Calc. for C16H22: C, 34.69; H, 4.00. Found: C, 34.62; H, 4.02.

[ Example  1 and 2] Organic semiconductor compounds (polymer 1 and 2) of  Produce

(200 mg, 0.49 mmol) and 4,7-bis (5-bromo-4- (2-octyldodecyl) thiophene- yl) benzo [c] [1,2,5] thiazol-thiazol ^{(R 3 = R 4 = H} ) or 4,7-bis (5-bromo-4- (2-octyldodecyl) thiophene -2 (R ³ = R ⁴ = F) (0.49 mmol) was added to the mixture, and anhydrous toluene (10 mL) was added thereto Melted. Pd (pph ₃ ) ₄ catalyst (10 mg, 0.03 eq) was dissolved in anhydrous DMF (1 mL) and added. After the completion of the reaction, the resulting solid was dissolved in chloroform, and the resulting solution was columned with Florisil to remove the catalyst. The resulting solid was recrystallized from methanol to obtain a purple solid. The resulting solid was dissolved in methanol and acetone And purified by an extractor (Soxhlet) to obtain polymer compounds 1 and 2, respectively. To the weight average molecular weight (Mw), number average molecular weight (Mn), PDI (polydispersity index ) , and the decomposition temperature (decomposition temperature, T _d) of the obtained polymer compound shown in Table 1.

Polymer Mn (g / mol) PDI T _d (° C) Example 1 Polymer 1 41,000 2.0 417 Example 2 Polymer 2 35,000 2.6 426

The polymers 1 and 2 prepared in Examples 1 and 2 were well dissolved in chloroform, THF and toluene, which are general organic solvents, at room temperature. The physical properties and optical characteristics of the obtained Polymers 1 and 2 are shown in Figs. 1 to 3.

The thermogravimetric analysis (TGA) curves of the polymers 1 and 2 prepared in Examples 1 and 2 are shown in FIG. 1. As shown in FIG. 1, the organic semiconductor compounds of the present invention are thermally stable.

Also, the polymers 1 and 2 prepared in Examples 1 and 2 were dissolved in an organic solvent such as chloroform to measure the UV absorption spectrum in a solution state and a solid film state, and they are shown in FIG. 2 and FIG.

As shown in FIG. 2, the polymers 1 and 2 prepared in Examples 1 and 2 exhibited an absorption of 300 to 750 nm in common in a UV absorption spectrum in a chloroform solution state, and a particularly strong vibronic peak was observed , Which can be seen as a peak due to strong interactions between molecules.

Further, as shown in Fig. 3, in the UV absorption spectrum of the film state of the polymer produced in Example 1, the absorption spectrum in a region wider than the absorption spectrum in the solution state can be observed. In the liquid state, the molecules are distributed over a wide range and can move relatively freely. However, in the case of the solid film state, the aggregation tendency phenomenon of each group can be regarded as a result. As a result of calculation of the bandgap (bandgap = 1240 /? _Edge ) using the absorption spectrum in the film state, the polymers 1 and 2 prepared in Examples 1 and 2 exhibited band gaps of 1.63 to 1.62 eV. Surprisingly, in the case of Polymer 2 (Example 2) in which four fluorine atoms were substituted, it exhibited a relatively high absorbance, and thus it is possible to predict excellent characteristics in organic solar cells.

In addition, the polymer prepared in Examples 1 and 2 was subjected to cyclic voltammetry using a ferrocene / ferrocenium redox system (-4.8 V) as a reference in a solid film state, HOMO levels of 1 and 2 were obtained. The HOMO levels of the two polymers were -5.36 eV for Polymer 1 and -5.43 eV for Polymer 2. The electron density in the molecule decreased as the amount of fluorine atoms having high electron accepting ability was increased, resulting in a low HOMO energy level. The LUMO energy level of each polymer was calculated as -3.73 to -3.81 eV as a difference from the band gap calculated in the UV absorption spectrum.

[ Example  3 and 4] Unit cell  Fabrication of organic solar cell device

A single layer organic solar cell device containing the organic semiconductor compound according to the present invention as a photoactive layer was prepared as follows.

UV-O ₃ was treated on clean ITO (Indium Tin Oxide) glass, and then ZnO was spin-coated at 5000 rpm for 1 minute and then heat-treated at 120 ° C for 10 minutes to form a 10 nm thick electron transport layer ETL).

The organic semiconductor compound (polymer 1 or polymer 2) according to the present invention and PCBM (C70) were added to 1,2-dichlorobenzene at a weight ratio of 1: 1.5 and stirred for 24 hours at 50 ° C for sufficient mixing. Compound mixture was prepared.

The organic semiconductor compound mixture solution was spin-coated under nitrogen on the ETL layer as a coating layer and then heat-treated at 120 ° C for 10 minutes to form a photoactive layer having a thickness shown in Table 2. Finally, MoO ₃ (10 nm) / Ag (100 nm) at a high temperature to fabricate an organic solar cell device.

In order to investigate the photovoltaic characteristics of the fabricated organic solar cell device, a solar simulator and a radiant power meter were used to generate 100 mW photovoltaic cells under AM 1.5 conditions, and a 1 kW solar simulator (Newport 91192) The current density-voltage characteristics of the organic solar cell device were measured using the photolithography method and the results are shown in FIG.

The photovoltaic parameters of the prepared organic solar cell device, that is, the electrical characteristics such as open circuit voltage (V _oc ), short-circuit current density (J _SC ), fill factor (FF) and overall conversion efficiency (photovoltaic parameters) are summarized in Table 2.

Photoactive layer Photoactive layer thickness
[nm] V _oc
[V] J _sc
[mA / cm ² ] FF
[%] PCE
[%] Example 3 Polymer 1 175 0.71 13.58 66 6.37 Example 4  Polymer 2 200 0.82 15.65 75 9.63

The organic solar cells of Examples 3 and 4 showed high photoelectric conversion efficiencies of 6.37% and 9.63%, respectively. In particular, the organic solar cell of Example 4 has a photoelectric conversion efficiency of 9% or more, which corresponds to the world's highest level of photoelectric conversion efficiency. Surprisingly, the organic solar cell of Example 4 showed a maximum efficiency at a thickness of 200 nm and a thick thickness of the photoactive layer. FIG. 5 shows the result of measuring the external quantum efficiency of the manufactured organic solar cell device. From this, the organic solar cell of Example 4 exhibits excellent external quantum efficiency of at least 75% at 500-700 nm, Supporting excellent J _sc in battery devices.

In general, the organic solar cell exhibits the highest light-to-electricity conversion efficiency at a photoactive layer thickness of less than 100 nm because the diffusion distance of the generated exciton is short. However, in the case of the polymer 2 synthesized in the present invention, as shown in FIG. 6, it is expected that it has a very good crystallinity and a molecular arrangement favorable to an organic solar cell, and thus exhibits high efficiency even with such a thick photoactive layer thickness.

Therefore, the polymer 2 developed in the present invention is suitable for application to a large-area sub-module organic solar cell through various roll-to-roll processes. In order to fabricate a large-area sub-module organic solar cell device, a polymer 2 exhibiting high efficiency in a unit device was selected to fabricate a large-area sub-module device in the following embodiments.

[ Example  5] Fabrication of large area sub-module organic solar cell device

In order to investigate the photovoltaic characteristics of the large-area sub-module organic solar cell device manufactured using the polymer 2 exhibiting the highest light-to-electricity conversion efficiency among the polymers produced in the examples as a new electron donor material, , A large-area sub-module organic solar cell device having a structure of [ITO / ZnO / organic semiconductor compound (polymer 2 of Example 2): PCBM (C71) / MoO ₃ / Ag] was prepared.

First, UV-O ₃ was treated on a cleaned strip-pattern ITO (Indium tin oxide) glass (length 100 mm and stripe length 8 nm), and then ZnO, an electron transporting layer, was deposited at a rate of 100 μm / Lt; / RTI > The ZnO layer was formed through slot die coating and then heat-treated at 200 ° C for 1 hour. The thickness of the ZnO layer after the heat treatment was 50 nm.

The organic semiconductor compound (polymer 2) according to the present invention and PCBM (C70) were added to 1,2-dichlorobenzene at a weight ratio of 1: 1.5 and stirred at 50 ° C for 24 hours for sufficient mixing to obtain an organic semiconductor compound mixture .

The photoactive layer was slot-die-coated on the ZnO layer at a rate of 60 μm / s at 80 ° C. and a thickness of 225 nm. Each module consists of 11 cells.

Finally, a MoO ₃ (10 nm) / Ag (80 nm) electrode was formed by vacuum deposition.

In the case of large-area submodule organic solar cells, the photoactive layer area was measured as 6600 mm ² .

[Comparative Example] Fabrication of PCE10 large area sub-module organic solar cell device

In order to compare the performance of the material developed in the present invention, a material showing high light-to-electricity conversion efficiency in a unit cell such as PCE10 that is being commercialized was used and a large area sub-module organic A solar cell device was fabricated.

In order to investigate the photovoltaic characteristics of the organic solar cell device fabricated in Example 5 and Comparative Example, a solar simulator and a radiant power meter were used to generate 100 mW of solar light having an AM 1.5 condition Current density-voltage characteristics of the organic solar cell device were measured using a 1kW solar simulator (Newport 91192), and the results are shown in FIG. 7 (right).

Large-area sub of Example 5 produced by using the polymer two-module organic solar cell element and the example of comparison made using the PCE10 large-area sub-module electrical characteristics of the organic solar cell device, that is, V _oc (open circuit Table 3 summarizes the photovoltaic parameters of voltage, short-circuit current density (J _SC ), fill factor (FF), and overall conversion efficiency (η)

Photoactive layer The photoactive layer thickness (d _ave )
[nm] V _OC
[V] J _SC
[mAcm ^-2 ] FF
[%] PCE
[%] Example 5 Polymer 2: PC ₇₁ BM 85 ± 22 8.12 1.13 64 5.82 225 ± 62 8.19 1.31 66 7.09 Comparative Example PCE10: PC ₇₁ BM 89 ± 19 8.34 1.27 50 5.29 248 ± 47 8.14 1.22 37 3.68

As shown in Table 3, in the case of the PCE10 being commercialized, the unit cell organic solar cell exhibits excellent light-to-electricity conversion efficiency of 8% or more, but in the large-area sub-module organic solar cell, the light- Efficiency. Also, in the large-area sub-module organic solar cell, the photoelectric conversion efficiency of 3.68% at the thickness 250 nm of the photoactive layer of PCE10 is shown.

However, the polymer 2 developed in the present invention exhibits a high light-to-electricity conversion efficiency of 7% or more at a thick thickness. This is a very favorable material for an organic solar cell process requiring a roll-to-roll process for commercialization. In addition, the light-to-electric conversion efficiency of 7% or more at 6600 mm ² is the world's highest photo-conversion efficiency.

That is, it is the world's first and highest efficiency to realize a photovoltaic cell that exhibits a light-to-electricity conversion efficiency of 7.09% by using the polymer 2, which is an organic semiconductor compound of the present invention, as a photoactive layer.

Claims (11)

An organic semiconductor compound having a repeating unit represented by the following formula
[Chemical Formula 1]

[In the above formula (1)
A is heteroarylene selected from the following structures;

X ¹ and X ² are each independently O or S;
R ^1, R ^2, R ⁵ and R ⁶ are each independently hydrogen, C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy, C ₁ -C ₃₀ alkylthio, C ₃ -C ₃₀ cycloalkyl, C ₁ - C ₃₀ alkoxycarbonyl C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy C ₆ -C ₃₀ aryl, C ₃ -C ₃₀ heteroaryl, , C ₃ -C ₃₀ heteroaryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkyl C ₃ -C ₃₀ heteroaryl or C ₁ -C ₃₀ alkoxy C ₃ -C ₃₀ heteroaryl;
R ³ and R ⁴ are each independently hydrogen or halogen;
Wherein said heteroaryl comprises at least one heteroatom selected from N, O and S.
delete delete The method according to claim 1,
Wherein the organic semiconductor compound is an organic semiconductor compound having a repeating unit represented by the following formula:
(2)

[In the formula (2)
R ¹ and R ² are each independently selected from the group consisting of hydrogen, C ₁ -C ₃₀ alkyl, C ₃ -C ₃₀ cycloalkyl, C ₁ -C ₃₀ alkoxy C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ Alkyl or C ₃ -C ₃₀ heteroaryl C ₁ -C ₃₀ alkyl;
R ³ and R ⁴ are each independently hydrogen or fluorine. 5. The method of claim 4,
Wherein R ¹ and R ² are each independently C ₁ -C ₃₀ alkyl. 6. The method of claim 5,
Wherein the organic semiconductor compound has a structure selected from the following structures as a repeating unit:

A method for producing an organic semiconductor compound having a repeating unit represented by the following formula (1) by copolymerizing a tin compound represented by the following formula (4) with a halide derivative represented by the following formula (3)
[Chemical Formula 1]

(3)

[Chemical Formula 4]

[In the above formulas (1), (3) and (4)
A is C ₆ -C ₃₀ arylene or C ₃ -C ₃₀ heteroarylene and the arylene and heteroarylene of A are selected from the group consisting of C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy, C ₁ -C ₃₀ alkyl alkylthio, C ₃ -C ₃₀ cycloalkyl, C ₁ -C ₃₀ alkoxy C ₁ -C ₃₀ alkyl, C ₆ -C ₃₀ aryl, C ₆ -C ₃₀ aryl C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkoxy C ₆ -C ₃₀ aryl, C ₃ -C ₃₀ heteroaryl, C ₃ -C ₃₀ heteroaryl, C ₁ -C ₃₀ alkyl, C ₁ -C ₃₀ alkyl, C ₃ -C ₃₀ heteroaryl and C ₁ -C ₃₀ alkoxy C ₃ It may further be substituted by one or more substituents selected from the group consisting of -C ₃₀ heteroaryl, and;
Y is halogen;
Wherein said heteroaryl and heteroarylene comprise at least one heteroatom selected from N, O and S. An organic electronic device comprising an organic semiconductor compound according to any one of claims 1 to 6. An organic solar cell device comprising an organic semiconductor compound according to any one of claims 1 and 4 to 6. 10. The method of claim 9,
Wherein the organic semiconductor compound is used as an electron-donating material. delete

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