KR101626363B1 - Anthracenyl alternating copolymer, preparation method thereof, and organic thin film transistor using the same - Google Patents

Abstract

The present invention relates to an anthracenyl-based alternating copolymer, a process for producing the same, and an organic thin film transistor using the same. When the anthracenyl-based alternating copolymer according to the present invention is applied to an organic thin film transistor, a high hole mobility and a high flicker ratio can be obtained, and an organic thin film transistor can be manufactured by a solution process, .

Organic polymer, organic thin film transistor

Description

TECHNICAL FIELD [0001] The present invention relates to an anthracenyl-based alternating copolymer, a method for producing the same, and an organic thin film transistor using the same. BACKGROUND ART [0002]

Anthracenyl based copolymer, a method for producing the same, and an organic thin film transistor using the same.

Electronic material technology using organic materials has received great attention in recent years. Representative examples that have been actively researched by many researchers and companies include organic electroluminescent diodes, organic solar cell materials, and organic transistor materials.

Organic semiconductor materials that replace amorphous silicon or polycrystalline silicon are attracting much attention due to their ease of processability and material development and their ability to form an active layer at low temperatures. Organic thin film transistors fabricated from conventional pentacene or similar materials with high charge mobility have gone a long way in commercial applications.

In the case of pentacene, which is a typical organic semiconductor compound, the value of p-channel charge mobility is reported to be about 3 cm ² / Vs when it is prepared as a single thin film ( J. Am. Chem. Soc. , 2008, 130, 2706). This dramatic performance improvement is accelerating the development of new core structures to develop new materials that can be used as active layers. However, these materials require expensive vacuum deposition equipment at the time of thin film formation, and are difficult to form fine patterns, and thus are not suitable for economic efficiency or large-scale production.

Merck manufactures and supplies oligomer organic semiconductor materials with a mobility of 1 cm ² / Vs ( J. Am. Chem. Soc. , 2008, 130, 2706). These materials have a structure in which five aromatic rings such as triisopropylsilyl (TIPS) -pentacene or difluoro (bis-triethylsilylanthradithiophene) (dF-TES-ADT) are fused to each other. And the like. The homogeneous organic semiconductor (homogeneous OSC) shows high initial mobility, but the polymer material is used as the binder to improve the characteristics of the thin film. Although these materials exhibit sufficient characteristics, it is difficult to apply them to a manufacturing line due to unstable device characteristics during the process for fabricating devices, and problems such as delay of voltage and reliability are reduced when current-electron sweeping is repeated have.

On the other hand, polymer materials show remarkable performance improvement in recent years. Recently, McKellough reported a thiophene polymer material exhibiting high mobility of 0.6 cm ² / Vs in Nature Materials ( Nature Mater ., 2006, 5, 328). The polymer materials reported by these documents have an advantage in that the active layer can be realized through solution processing such as printing technique in terms of processability, thereby achieving a large-sized large-sized polymer material at low cost. In addition, although the mobility is relatively low as compared with a low-molecular material or an inorganic material, a transistor device can be manufactured at a low cost because a high operating frequency is not required.

Semiconductor organic compounds are currently being developed in areas such as organic thin film transistors (OTFTs), organic light emitting diodes (OLEDs), sensors and photovoltaic devices. Among them, the organic thin film transistor has attracted attention as a most suitable technology for realizing a large-area and low-cost display, and it is reported that it is close to a performance which can be applied to mass production on a commercial scale.

Conventionally, a lot of low-molecular-weight pentacene precursors and oligomeric polythiophene derivatives as an organic semiconductor material have been studied. Examples thereof include organic semiconductor materials such as the following compounds 1 to 3.

Low molecular weight pentacene precursors or pentacene derivatives have been reported to exhibit high charge mobilities of 3.2 to 5.0 cm 2 / Vs or more, but they are not suitable for commercial use because they do not exhibit stable performance due to self-denaturation of the material after film formation . In addition, although it is possible to produce a thin film by a solution process, there is a disadvantage in that it causes phase aggregation due to heat generated during driving. In order to compensate this, the uniformity of the film may be increased by incorporating a large amount of different kinds of polymer materials.

Pentacene having the following structure can maximally increase intermolecular overlap, but this arrangement has a disadvantage in that it varies in various conditions. In addition, since the benzene ring in the central portion has a chemically unstable structure, the structure of sp ² carbene has chemical instability that changes into a heterogeneous structure such as -C = O.

On the other hand, the instability of molecules such as pentacene has not been reported in the above-mentioned structured thiophene molecules, and mobility has been improved by introducing an alkyl group, but it is still not yet commercialized and needs improvement.

In addition, poly-3-alkylthiophene having the following structure shows high mobility in the regio-regular structure, but has not reached commercial level yet. This is due to the lack of thermal / chemical stability of the molecule and the introduction of a new structure into the main chain to obtain high mobility properties in polymers.

Therefore, in order to commercialize an organic thin film transistor, it is required to provide an organic thin film transistor having excellent electrical stability and economical efficiency in order to make it possible to secure electrical / thermal stability based on a single component and to exhibit excellent thin film properties even if the solution process is carried out at room temperature Design and synthesis of satisfying polymer materials are required.

It is an object of the present invention to overcome the limitations of the prior art as described above and to provide a method of manufacturing a semiconductor device which is excellent in electrical stability and economical efficiency and which can exhibit excellent thin film properties even when a solution process is performed at room temperature And to provide a polymeric material which enables the polymeric material to be obtained.

The above object of the present invention is achieved by the following.

(1) An anthracenyl polymer having a repeating unit represented by the following formula (1):

[Chemical Formula 1]

(2) An organic thin film transistor comprising the polymer of (1).

(3) reacting a compound represented by the formula (2) with a compound represented by the formula (3) to obtain a compound represented by the formula (4)

(b) a step of polymerizing the compound of formula (4) with a compound of formula

A process for producing a polymer according to claim 1, comprising:

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

An anthracenyl-based alternating copolymer according to the present invention, a method for producing the same, and an organic thin film transistor using the same are provided. The anthracenyl-based alternating copolymer according to the present invention has various substituents introduced therein, facilitating charge transfer within a molecule or between molecules, and capable of superposing a strong pervital. Therefore, when this material is used as an active layer of an organic thin film transistor, And a high blink ratio can be obtained. In addition, in the present invention, since the active layer of the organic thin film transistor can be manufactured by the solution process, the manufacturing cost can be reduced.

The present invention relates to an anthracenyl-based polymer represented by the following formula (1).

[Chemical Formula 1]

_Wherein each R < ₁ > is independently a linear or branched alkyl group having from ₁ to ₁₀ carbon atoms,

-Ar- has the following structure, in which R ₂ is a C _6-12 linear or branched alkyl group,

Or a group selected from the group consisting of the following structures,

,

,

,

,

,

,

,

,

,

및

,

And

R is a C _6-12 linear or branched alkyl group,

X is a sulfur or selenium atom,

Y is a carbon or silicon atom,

m is an integer of 1 to 4;

In the above formula (1), R ₁ is preferably an ethyl group or an isopropyl group as an alkyl group enabling the solution process, and most preferably all of the six R ₁ groups are isopropyl groups. This part not only enables the solution process, but also plays a role in improving the charge transfer by enabling effective inter-molecule superimposition when a thin film is formed.

When Y is silicon, it is possible to transfer an electric charge more improved than carbon because of its electrical characteristics, which is desirable.

Ar is, on the other hand, an aryl or heteroaryl ring, preferably substituted with a linear alkyl group, which may contain a sulfur or selenium atom in the ring. The aryl group allows an alternating copolymerization reaction to proceed, and also helps to overlap? -Ins between molecules.

Most preferably, R < _{2 >} is hexyl or dodecyl.

In addition, -Ar- may be selected from the group consisting of the following structures.

Specific examples of the polymer represented by the formula (1) include those having a repeating unit selected from the group consisting of the following formulas.

및

And

The present invention also relates to a process for preparing a polymer represented by the above formula (1), comprising the steps of: (a) reacting a compound represented by the following formula (2) with a compound represented by the formula (3) And (b) subjecting the compound of formula (4) to a polymerization reaction with a compound represented by the following formula (5).

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the formulas (2) to (5), R ₁ , -Ar-, X, Y, m and n are the same as defined above and Z is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine.

The present invention also relates to an organic thin film transistor including the polymer represented by Formula 1 above.

Example

Hereinafter, the present invention will be described in detail with reference to examples. However, the examples are merely examples of the present invention, and the scope of the present invention is not limited by these examples.

Example 1

(1) Preparation of dibromoanthradithiophene

(0.63 g, 5.6 mmol) and 2.1 equivalent of 5-bromo-2,3-thiopendicarboxaldehyde were placed in a two-necked 100 mL flask, refluxed for 10 minutes in nitrogen, 100 mL of ethanol was added. A brown precipitate was formed after slowly adding 15% aqueous KOH solution to the mixture. After stirring for about 4 hours, the mixture was filtered and washed again with ethanol to obtain a dark brown Compound 1 in a yield of 78%.

(2) Preparation of dibromo-bis (triisopropylsilylethynyl) anthradithiophene

2.1 mL of triisopropylsilyl acetylene was placed in a 100 mL two-necked flask together with 20 mL of hexane, purged with nitrogen, and 4 equivalents of butyllithium was slowly added thereto, followed by heating at 60 DEG C for 1 hour. The reaction mixture was cooled to room temperature, 1 equivalent of Compound 1 was added thereto, and the mixture was further stirred at 60 DEG C for 24 hours to give a dark brown solution. To the reaction mixture, a 10% SnCl ₂ -2H ₂ O aqueous hydrochloric acid solution was slowly added and stirred at 60 ° C for 2 hours, then cooled, dried over MgSO ₄ and filtered. Hexane to obtain dibromo-bis (triisopropylsilylethynyl) anthradithiophene (Compound 2) in a deep red solid state at a yield of 65%.

(3) Preparation of 2,5-di (trimethyltin) -3-dodecylthiophene

3-dodecylthiophene (1 g, 3.96 mmol) was added to a two-necked flask, and the mixture was maintained at -78 ° C for 30 minutes. The reaction temperature was raised to room temperature, and after 10 minutes, the temperature was again lowered to -78 ° C, and a THF (10 mL) solution of trimethyltin chloride (3 equivalents) was slowly added thereto and stirred for 24 hours while gradually warming to room temperature. The organic layer was collected by distillation under reduced pressure, and then filtered through celite to obtain 2,5-di (trimethyltin) -3-dodecylthiophene (Compound 3) in a yield of 62%.

(4) Production of polymer of Example 1

In a 50 mL two-necked flask, 1.5 mmol of each of compounds 2 and 3 were added, and the mixture was purged with nitrogen. 50 mg of Pd (PPh ₃ ) ₂ Cl ₂ was added thereto, and 30 mL of anhydrous THF was added thereto. The reaction mixture was cooled to room temperature and then poured into methanol, filtered and dried, reprecipitated twice in methanol / THF, and the metal impurities were removed by short column chromatography and then subjected to Soxhlet extraction to obtain The compound was obtained in 45% yield . Molecular weight determined by GPC: Mn = 15000, Mw = 27000

Example 2

(1) Preparation of 2,2'-bis (trimethyltin) -3,3'-di-dodecylthiophene

2,2'-bis (trimethyltin) -3,3'-di-dodecylthiophene (Compound 4) was obtained in a yield of 58% in the same manner as in (3) of Example 1.

(2) Preparation of Polymer of Example 2

1.5 mmol of each of the compounds 2 and 4 were placed in a 50 mL two-necked flask, purged with nitrogen, and then 50 mg of Pd (PPh ₃ ) ₂ Cl ₂ was added thereto, and 30 mL of anhydrous THF was added thereto and refluxed for 3 days. The reaction mixture was cooled to room temperature and then poured into methanol, filtered and dried, reprecipitated twice in methanol / THF, the metal impurities were removed by short column chromatography and then subjected to Soxhlet extraction to obtain The compound was obtained in 39% yield . Molecular weight determined by GPC: Mn = 12000, Mw = 21000

Example 3

(1) Preparation of 5,5'-bis- (trimethyltin) -3,3'-di-n-octylsilylene-2,2'-bithiophene

5,5'-bis- (trimethyltin) -3,3'-di-n-octylsilylene-2,2'-bithiophene (Compound 5) was obtained in the same manner as in (3) 52% yield.

(2) Preparation of polymer of Example 3

In a 50 mL two-necked flask, 1.5 mmol of each of the compounds 2 and 5 was added, and the mixture was purged with nitrogen. 50 mg of Pd (PPh ₃ ) ₂ Cl ₂ was added thereto, and 30 mL of anhydrous THF was added thereto. The reaction mixture was cooled to room temperature and then poured into methanol, dried by filtration, reprecipitated twice in methanol / THF, the metal impurities were removed by short column chromatography and then subjected to Soxhlet extraction to obtain The compound was obtained in 45% yield . Molecular weight determined by GPC: Mn = 11000, Mw = 1950

Example 4: Fabrication of device

Organic thin film transistor devices were fabricated as described below using the polymers synthesized in Examples 1 to 3 of the present invention as active layers, respectively.

As the gate electrode, a silicon dioxide (SiO ₂ ) thin film was deposited on the heavily doped n-type silicon wafer by chemical vapor deposition (CVD) to a thickness of 200 nm.

The polymers synthesized in Examples 1 to 3 as the active layer were each dissolved in chlorobenzene A thin film having a thickness of 50 nm was formed by spin coating, and gold (Au) was formed thereon as a source electrode and a drain electrode with a shadow mask, and the thickness was set to 50 nm. The channel length (L) and channel width (W) were 50 μm and 1.5 mm, respectively, and the device was configured to have the structure shown in FIG.

Electrical characterization was measured with a Keithley semiconductor parametric analyzer (Keithley 4200) under an inert atmosphere of nitrogen. The mobility (μ) of the charge in the saturation region was calculated using the following equation.

Where Ci is the capacitance per area [SiO ₂ dielectric (Ci = 15 nF / cm ² )] and VT is the operating voltage.

(1) Fabrication of Organic Thin Film Transistor Using Polymer of Example 1

The silicon oxide layer was treated with octyltrichlorosilane (OTS) to improve interfacial contact between the inorganic-active organic material layer, and then the polymer synthesized in Example 1 was dissolved in chlorobenzene and spin-coated to form a film. Then, a source and a drain were formed using a gold mask using a gold electrode, and mobility was measured in a glove box. The hole mobility was 0.003 cm ² / Vs and the blink ratio was 10 ⁵ .

(2) Fabrication of Organic Thin Film Transistor Using Polymer of Example 2

The silicon oxide layer was treated with octyltrichlorosilane (OTS) to improve interfacial contact between the inorganic-active organic material layer, and then the polymer synthesized in Example 2 was dissolved in chlorobenzene and spin-coated to form a film. Then, a source and a drain were formed using a gold mask using a gold electrode, and mobility was measured in a glove box. The hole mobility was 0.0011 cm ² / Vs, and the blink ratio was 10 ⁵ .

(3) Fabrication of Organic Thin Film Transistor Using Polymer of Example 3

The silicon oxide layer was treated with octyltrichlorosilane (OTS) to improve interfacial contact between the inorganic-active organic material layer, and then the polymer synthesized in Example 3 was dissolved in chlorobenzene to form a film by spin coating. Then, a source and a drain were formed using a gold mask using a gold electrode, and mobility was measured in a glove box. The hole mobility was 0.004 cm ² / Vs and the blink rate was 10 ⁵ .

Table 1 below summarizes the results of characterization of organic thin film transistors fabricated using the polymers of Examples 1 to 3.

1 is a schematic diagram of a device structure manufactured in an embodiment of the present invention.

FIGS. 2A and 2B are graphs showing electrical property measurement results of a device fabricated using the polymer synthesized in Examples 1 to 3 of the present invention as an active layer. FIG. (Black Example 1, red: Example 2, green: Example 3)

Claims (8)

An anthracenyl polymer having a repeating unit represented by the following formula (1) [Chemical Formula 1]

_Wherein each R < ₁ > is independently a linear or branched alkyl group having from ₁ to ₁₀ carbon atoms, -Ar- has the following structure, in which R ₂ is a C _6-12 linear or branched alkyl group,

Or a group selected from the group consisting of the following structures,

,

,

,

,

,

,

And

R is a C _6-12 linear or branched alkyl group, X is a sulfur or selenium atom, Y is a carbon or silicon atom, m is an integer of 1 to 4; The anthracenyl polymer according to claim 1, wherein R ₁ is ethyl or isopropyl. The anthracenyl polymer according to claim 1, wherein all of the six R ₁ groups are isopropyl. 2. The polymer of claim 1, wherein R < _{2 >} is a hexyl or dodecyl-anthracenyl polymer. The anthracenyl polymer according to claim 1, wherein -Ar- is selected from the group consisting of the following structures:

And

. The anthracenyl polymer according to claim 1, wherein the anthracenyl polymer is selected from the group consisting of:

And

. An organic thin film transistor comprising an anthracenyl polymer according to any one of claims 1 to 6. (a) reacting a compound represented by the following formula (2) with a compound represented by the formula (3) to obtain a compound represented by the formula (4) (b) a step of polymerizing the compound of formula (4) with a compound of formula A process for producing the anthracenyl polymer according to claim 1, comprising: (2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

Wherein R ₁ , -Ar-, X, Y and m are the same as defined in claim ₁ , and Z is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine.

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