KR20100114280A - Photo-curable diamine monomer and polyimide, and organic thin film transistor using the same as insulator - Google Patents

Abstract

PURPOSE: A photo-curable diamine monomer and polyimide, and organic thin film transistor using the same as an insulator are provided to improve the packing density and insulating property of an organic insulator thin film as well as to improve the chemical resistance of the thin film. CONSTITUTION: In a photo-curable diamine monomer and polyimide, and organic thin film transistor using the same as insulator, the molecular weight of polyimide is within 5,000-1,000,000 g/mol. The intrinsic viscosity of the polyimide is within 0.1-1.5dL/g. The polyimide has an insulating film formation temperature of 100-300300°C.

Description

Photocurable diamine monomers and polyimides and organic thin film transistors using them as insulators

The present invention relates to a novel diamine derivative and polyimide that can be used as an organic insulator, which is a key component of an organic thin film transistor, and an organic thin film transistor using the same as an organic insulating film.

Since the 1980s, researches on organic thin film transistors (OTFTs) using organic materials as active layers have been actively conducted worldwide. The organic thin film transistor is structurally similar to the conventional silicon transistor (Si-TFT), but there is a difference in using an organic material instead of silicon in the semiconductor region. The organic thin film transistor is capable of using a spin coating or printing method of atmospheric pressure instead of a physical / chemical deposition method using an inorganic thin film of a conventional silicon transistor, thereby simplifying the manufacturing process and having a low temperature process.

In general, as an insulator of the organic thin film transistor, inorganic silicon dioxide (SiO ₂ ) is used, and as organic materials, polyvinyl alcohol (PVA), polyvinylphenol (PVP), polymethyl methacrylate (PMMA) and polyimide Substances, such as (PI), are used. Since the insulator forms an interface with the organic semiconductor, the crystallinity and shape of the organic semiconductor depend on the interface characteristics of the insulator, which is an essential part of the device characteristics of the final thin film transistor.

Among the insulators using organic materials, polyvinyl alcohol (PVA) or polyvinylphenol (PVP) -based organic insulators have been limited in application to flexible substrates because thermal curing reactions are introduced at high temperatures by introducing a curing agent. Even after curing, hydroxy (OH) groups are included in the structure, and thus, when the organic insulating film made of such a material is applied to the organic thin film transistor, there are problems such as leakage current and hysteresis by the hydroxy group. .

Conventional polyimide polymers can be divided into a case of melting in a general organic solvent and a case of forming a final organic insulating film through a high temperature heat treatment process after forming the insulating film in a polymer precursor state. In the former case, the final polymer may be melted in an organic solvent to proceed to a thin film process to form a final insulating film through low temperature solvent drying.However, the side chain of the polymer introduced to increase the solubility may include insulation characteristics and chemical resistance of the organic insulating film. There was a downside to dropping. Despite these problems, development of soluble organic insulators is important for the implementation of next-generation low-cost displays and organic devices.

In order to obtain the excellent characteristics of the organic thin film transistor, it is necessary to develop an organic insulator having excellent insulating properties, and in order to implement the organic thin film transistor on a flexible substrate, the temperature of forming the organic insulator thin film must be low temperature process. In addition, the organic insulator needs to be patterned in order to manufacture an actual array device using the organic thin film transistor. Therefore, it is necessary to develop an organic insulator having excellent solubility in the solvent used in the solution process and excellent chemical resistance to the solvent used in the subsequent solution process so that the organic insulating film can be easily patterned through a printing process.

In order to solve the above problems, the present invention seeks to develop a novel diamine derivative capable of photocuring without the addition of a photoinitiator and a novel polyimide polymer soluble in an organic solvent and capable of low temperature processing. In addition, an object of the present invention is to develop an organic thin film transistor capable of minimizing leakage current and hysteresis by applying the polyimide polymer as an organic insulator.

In order to achieve the above object, the present invention is to develop a novel diamine monomer capable of photo curing and to develop a new polyimide polymer that can be photo cured by the reaction of the diamine monomer and an acid dianhydride, excellent electrical properties and process method We want to develop an improved organic insulator. In addition, to provide an organic thin film transistor equipped with this organic insulator.

Hereinafter, the present invention will be described in detail.

The present invention provides a polyimide polymer selected from the following Chemical Formula 1, Chemical Formula 2 and Chemical Formula 3 as a novel polyimide organic insulator which is soluble in an organic solvent and capable of photocuring.

[Formula 1]

[Formula 2]

(3)

는

,

,

,

,

,

,

,

,

,

,

및

로 이루어진 군으로부터 선택되는 1종 이상의 4가기이며;In Formula 1, Formula 2 and Formula 3,

Is

,

,

,

,

,

,

,

,

,

,

And

At least one tetravalent group selected from the group consisting of:

는

,

,

,

,

,

,

,

,

및

로 이루어진 군으로부터 선택되는 1종 이상의 2 가기이며;

Is

,

,

,

,

,

,

,

,

And

At least one 2-group selected from the group consisting of;

q is an integer from 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C1-C10 alkyl, cyano or halogen substituents;

The sum of m, n and l is an integer from 10 to 3,000 (m contains 0).

Prior to describing any one of the polyimide polymers selected from Chemical Formulas 1, 2 and 3, the present invention provides a novel diamine monomer capable of photocuring as a starting material for preparing a polyimide polymer. A diamine derivative of formula 5 was developed.

[Formula 4]

[Chemical Formula 5]

In Chemical Formulas 4 and 5, q is an integer of 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C 1 -C 10 alkyl, cyano or halogen substituents.

The diamine derivative represented by Chemical Formula 4 or Chemical Formula 5 is capable of photocuring and finally preparing a polyimide polymer having properties desired by the inventor of the present invention. In other words, the diamine derivative can produce a novel polyimide polymer, the polyimide polymer prepared is well dissolved in an organic solvent and photocurable, and can minimize leakage current and hysteresis as an organic insulator of an organic thin film transistor. Take advantage of that.

In the present invention to prepare the diamine derivative,

a) dissolving 3,5-dinitro benzyl alcohol to reduce the catalyst and under reduced pressure to obtain a solid of 3,5-diamino benzyl alcohol;

b) 3,5-diamino benzyl alcohol and di-tert-butyl dicarbonate (di-t-BOC) are dissolved and reacted under a catalyst to di-tert-butyl-5- (hydroxymethyl) -1,3- Obtaining a phenylenedicarbamate solid;

c) dissolving di-tert-butyl-5- (hydroxymethyl) -1,3-phenylenedicarbamate and adding a halide of Formula 7 or Formula 8 to obtain a compound of Formula 9 or Formula 10 Making; And

d) dissolving a compound of Formula 9 or Formula 10 and adding trifluoroacetic acid to obtain a diamine derivative of Formula 4 or Formula 5;

It consists of.

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

In Formulas 7 to 10, q is an integer of 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C 1 -C 10 alkyl, cyano or halogen substituents.

Step a) relates to a reduction reaction using hydrogen, and a C 2 -C 10 alkyl alcohol or 3,5-dinitro as a solvent for dissolving 3,5-dinitro benzyl alcohol. A solvent having solubility for benzyl alcohol is selected, preferably ethanol is used. As the catalyst added in step a), a noble metal catalyst including Pt, Pd, Ru, Ag, Au is used, and preferably a Pd / C catalyst is used. 1 to 20% by weight of 3,5-dinitrobenzyl alcohol and 0.1 to 3,5-dinitrobenzyl alcohol based on the mixture of 3,5-dinitrobenzyl alcohol, solvent and catalyst charged to the hydrogen reactor To 1% by weight, and the rest as a solvent. The reaction is reduced for 1 to 12 hours under atmospheric pressure to 10 atmospheres. After the reaction, the catalyst was removed using a membrane filter, the reaction mixture was concentrated under reduced pressure and recrystallized from a solvent such as ethanol to obtain 3,5-diamino benzyl alcohol as a brown solid. .

Scheme 1

In step b), 3,5-diamino benzyl alcohol obtained in step a) is added to a flask immersed in an ice bath, dissolved by adding a mixed solvent, and then di-tert-butyl dicarbonate; di -t-BOC) is added and sodium carbonate (Na ₂ CO ₃ ) is added as a catalyst. The solids of the 3,5-diamino benzyl alcohol, di-tert-butyl dicarbonate and the catalyst with respect to the total reactants are preferably 5 to 40% by weight, with the remainder being a solvent. As the mixed solvent, it is preferable to use a solvent obtained by mixing 1,4-dioxane / water (1,4-dioxaene / H ₂ O) in a volume ratio of 4/1 to increase the solubility. The molar ratio of 3,5-diamino benzyl alcohol: di-tert-butyl dicarbonate is from 1: 1 to 5, preferably from 1: 2 to 3. The sodium carbonate is preferably added 2 to 10 moles, preferably 3 to 5 moles per 1 mole of 3,5-diamino benzyl alcohol. The reaction is sufficiently stirred under the low temperature of the ice bath to dissolve the solid content and the temperature is raised to room temperature to react for 1 to 12 hours, preferably 6 to 7 hours. The reaction mixture was filtered to remove sodium carbonate, concentrated under reduced pressure, diluted sufficiently under ethanol and the polar solvent in ethanol was removed using an aqueous sodium chloride solution. Finally, water was removed using anhydrous magnesium sulfate and recrystallized. Di-tert-butyl-5- (hydroxymethyl) -1,3-phenylenedicarbamate is obtained as a solid.

Scheme 2

In the step c), the di-tert-butyl-5- (hydroxymethyl) -1,3-phenylenedicarbamate obtained in the step b) is added to a flask immersed in an ice bath and dissolved by adding a solvent. A halide such as Formula 7 or Formula 8 is added and stirred. Examples of the halides include cinnamoyl chloride, 3-naphthalen-1-yl-acryloyl chloride, 3-biphenyl-4-yl-acrylo Monochloride (3-Biphenyl-4-yl-acryloyl chloride, etc. is added and stirred.) At low temperature in an ice bath, an alkylamine, such as triethylamine (TEA), is injected and heated to room temperature for 1 to 24 hours. The solvent may be an organic solvent having solubility in both the reactant and the catalyst, and preferably methylene chloride (MC), using di-tert-butyl-5-. (Hydroxymethyl) -1,3-phenylenedicarbamate, halides and Alkylamine is added in an amount of 1 to 20% by weight, with the remainder being a solvent. The molar ratio of di-tert-butyl-5- (hydroxymethyl) -1,3-phenylenedicarbamate: halide: alkylamine is 1: 1 to 5: 2 to 10, preferably 1: 1 It is advantageous to obtain a product in the range of 2 to 1 to 4. After the reaction mixture is mixed using a known polar solvent removal method, water removal method, purification method to obtain a compound of the formula (9) or (10).

Scheme 3

In step d), the compound of Formula 9 or Formula 10 obtained in step c) is dissolved in a solvent, and trifluoroacetic acid (CF ₃ COOH) is added thereto, followed by reaction for 1 to 12 hours at room temperature. . As the solvent, any solvent having high solubility with respect to the reactant may be used, and methylene chloride (MC) is preferably used. 1 to 5% by weight of the compound of Formula 9 or 10 is added to the mixed reactant, and trifluoroacetic acid should not exceed 50% by weight of the mixed reactant. Insert as much as possible. After the reaction mixture, a novel diamine derivative such as Chemical Formula 4 or Chemical Formula 5 is obtained by using a known polar solvent removal method, water removal method, or purification method.

The present invention is a 3,5-diamino benzyl cinnamate (DABC), 3-naphthalen-2-yl-acrylic acid-3,5-diamino-benzyl ether ( NAP) and 3-biphenyl-4-yl-acrylic acid-3,5-diamino-benzyl ether (BIP) and the like. In addition, the diamine derivatives prepared in this way have the advantage of curing using UV light without applying heat, and by using this, polyimide used as an insulator of organic thin film transistors is developed to cure only with UV light without a photo initiator at low temperature. Possible photocured polyimides can be prepared.

The present invention can produce a polyimide using the novel diamine monomer represented by Formula 4 or Formula 5 prepared above.

In the present invention, in preparing a polyimide organic insulator which is soluble in an organic solvent and photocurable, a tetracarboxylic dianhydride and a diamine of the following Chemical Formula 6 may be used as a diamine derivative of one or a mixture selected from Chemical Formula 4 or Chemical Formula 5. By mixing the monomers in an appropriate ratio, it is possible to prepare a polyimide organic insulator polymer having excellent solubility while minimizing degradation of mechanical properties and heat resistance.

[Formula 6]

는

,

,

,

,

, ,

,

,

,

및

로 이루어진 군으로부터 선택되는 1종 이상의 2 가기이다.In Chemical Formula 6,

Is

,

,

,

,

,,

,

,

,

And

At least one 2 member selected from the group consisting of:

The tetracarboxylic dianhydride,

1,2,3,4-cyclobutane tetracarboxylic dianhydride [CBDA], 1,2,3,4-cyclopentane tetracarboxylic dianhydride [CPDA], 5- (2,5-dioxotetrahydrofuryl ) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA], 4- (2,5-dioxotetrahydrofuryl-3-yl) -tetraline-1,2-dicarboxyl One or two or more aliphatic dianhydrides selected from acid dianhydride [DOTDA] and bicyclooctene-2,3,5,6-tetracarboxylic dianhydride [BODA]; Or one or two or more aromatic tetracarboxylic dianhydrides selected from pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, oxydiphthalic dianhydride, nonphthalic dianhydride, and hexafluoroisopropylidenediphthalic dianhydride. It may be included, it is preferable to use 5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA].

As an example of the diamine monomer of the formula (6),

Para-phenylenediamine ( p- PDA), meta-phenylenediamine ( m- PDA), 4,4-oxydianiline (ODA), 4,4-methylenedianiline (MDA), 2,2-bisamino Phenylhexafluoropropane (HFDA), metabisaminophenoxydiphenylsulfone ( m- BAPS), parabisaminophenoxydiphenylsulfone ( p- BAPS), 1,4-bisaminophenoxybenzene (TPE-Q) 1 selected from 1,3-bisaminophenoxybenzene (TPE-R), 2,2-bisaminophenoxyphenylpropane (BAPP) and 2,2-bisaminophenoxyphenylhexafuluropropane (HFBAPP) Species or two or more aromatic diamines may be included, preferably 4,4-methylenedianiline (MDA).

In preparing the polyimide polymer of the present invention, examples of the diamine monomer of the general formula (4) or the general formula (5) capable of polymerization reaction with the tetracarboxylic dianhydride,

3,5-diaminobenzyl cinnamate, 3-naphthalen-2-yl-acrylic acid-3,5-diamino-benzyl ether and 3-biphenyl-4-yl-acrylic acid-3,5-diamino-benzyl ether It is preferable to select one diamine derivative selected from the like.

The diamine monomer of one kind or mixture selected from the general formula (4) or (5) capable of photocuring is polymerized in the same equivalent amount as the tetracarboxylic dianhydride monomer, or the diamine monomer of one kind or mixture selected from the general formula (4) or (5). In addition to the tetracarboxylic dianhydride monomer in addition to the aliphatic or aromatic diamine monomer represented by the formula (6) through the polymerization of the copolymerized form can be prepared a polyimide polymer that can finally adjust the degree of curing, solubility and surface energy.

In addition, the present invention can be prepared by adding an aliphatic or aromatic diamine monomer of the formula (6) to further increase the degree of polymerization of the tetracarboxylic dianhydride monomer and the diamine monomer of one or a mixture selected from formula (4) or (5). have. Preferably, 4,4-methylene dianiline (MDA) may be added as the diamine monomer of Chemical Formula 6 to prepare one or more polyimide polymers selected from Chemical Formula 1, Chemical Formula 2 and Chemical Formula 3.

The soluble polyimide polymer prepared using the diamine monomer of Formula 4 or Formula 5 may include an organic thin film transistor formed by forming an organic insulator thin film through a solution process and applying the same.

The polyimide polymer of the present invention has a weight average molecular weight in the range of 5,000 to 1,000,000 g / mol, has an intrinsic viscosity of 0.1 to 1.5 dL / g, the glass transition temperature (Tg) of 150 to 400 ℃ range. In addition, the photocurable and soluble polyimide polymers according to the present invention are aprotic such as dimethylacetamide (DMAc), dimethylformamide (DMF), N -methyl-2-pyrrolidone (NMP), acetone, ethyl acetate and the like. In addition to polar solvents, organic solvents such as meta-cresol (m-crasol) are easily dissolved at room temperature. In particular, low solubility solvents such as tetrahydrofuran (THF), chloroform, and low absorption solvents such as gamma-butyrolactone also exhibit high solubility of at least 10% by weight at room temperature. Moreover, high solubility is shown also about these mixed solvents.

Soluble polyimide polymer represented by Formula 1, Formula 2 and Formula 3 according to the present invention, the surface tension is in the range of 20 to 60 dyne / cm, the dielectric constant is in the range of 2 to 6.

Photocurable soluble polyimide resin according to the present invention is capable of forming a fine pattern of 10 to 50 ㎛ by irradiation with ultraviolet light (UV) having a wavelength of 260 to 400 nm, polycarbonate due to excellent solubility (polycarbonate), polysulfone (polysulfone), polyether sulfone (polyether sulfone), such as a low temperature process on the plastic substrates have excellent properties. Preferably, the novel polyimide organic insulator of the present invention, in which the photocuring machine is introduced, can be used as an insulating thin film of an organic thin film transistor to form an insulating thin film at a low temperature of 50 to 160 ° C. Polyimide resin. 1 is shown to help understand the light curing mechanism of the polyimide of the present invention.

In an organic thin film transistor including a gate electrode, an organic insulating film, an organic active layer, a source / drain electrode, and a protective layer on a substrate, the organic insulating film may use the polyimide polymer of the present invention. The organic insulating film of the organic thin film transistor may be formed using a spin coating method, an inkjet printing method, a dipping method, or the like, and the thickness of the organic insulating film formed by the thin film coating method has a range of 30 to 900 nm.

The present invention is an organic active layer of an organic thin film transistor using at least one polyimide selected from Formulas (1), (2) and (3) as an organic insulating film, pentacene, metal phthalocyanine, polythiophene, polyphenylenevinylene, C By using a compound selected from the group consisting of ₆₀ , phenylene tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, fluorinated phthalocyanine and derivatives thereof, the electrical properties of the organic thin film transistor can be further improved.

The electric field mobility of the organic thin film transistor including at least one polyimide selected from Chemical Formulas 1, 2, and 3 as the organic insulating layer and including the organic active layer was measured to have a range of 0.01 to 10 cm 2 / Vs. .

Thus, the excellent electrical, chemical, and physical properties of the organic thin film transistor manufactured by the present invention are expected to be widely applied as various display devices such as flexible displays and sensors, and are a technology that must be applied in the next-generation organic device technology.

The present invention is a novel organic insulator that can be applied to an organic thin film transistor (OTFT) as a driving switching element in a next-generation flexible display and can be processed at low temperature and photocured. Conventional polyimide polymers require a high process temperature when converting from polyamic acid to final polyimide polymers, but the polyimide polymers of the present invention have a good solubility in existing organic solvents, and thus can form thin films at low temperatures and The packing density and insulation property of the organic insulator thin film are improved by introducing into the curable novel diamine derivative polymer main chain and finally curing the polymer chain through photocuring. In addition, through the photocuring of the organic insulator thin film, the chemical resistance of the thin film is improved, and the patterning property is important in the actual array device fabrication process.

The photocurable novel polyimide organic insulator developed in the present invention has no problem in realizing a device of a flexible plastic substrate since the low temperature process is possible when using the organic insulating thin film.

The novel photocurable diamine monomer may be used to polymerize various dicarboxylic dianhydrides and diamine derivatives to prepare organic insulating polymers having excellent properties.

Therefore, the novel photocurable polyimide organic insulator of the present invention can be widely applied as a driving switch to a next-generation flexible display and a sensor, and can improve process temperature, chemical resistance, electrical characteristics, etc. as compared to the existing organic insulator. Can be.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the invention only.

[ Production Example  One] Photocuring  possible Diamine  Monomer [ DABC Manufacture of

3,5- Diamino  Benzyl alcohol [3,5- Diamino benzyl alcohol Preparation (Compound 1):

 100 mL of ethanol was added to a hydrogen reactor, and 10 g of 3,5-dinitrobenzyl alcohol was dissolved. After adding 1 g of Pd / C (5%) as a catalyst, a reduction reaction was carried out for 5 to 6 hours at a pressure of 3.5 atm. The solid obtained by concentrating the reaction mixture from which the Pd / C was removed using the membrane filter under reduced pressure was recrystallized in ethanol to obtain a brown solid.

Di - tert - butyl-5- (hydroxymethyl) -1,3-phenylene dicarboxylic carbamate [Di - tert - butyl-5- (hydroxymethyl) -1,3-phenylenedicarbamate] Preparation (Compound 2):

6 g of Compound 1 was added to a 500 mL round bottom flask equipped with an ice bath and dissolved by adding 240 mL of 1,4-dioxane / water (1,4-dioxane / H ₂ 0; volume ratio 4/1) mixed solvent. After the addition, 13.8 g of Na ₂ CO ₃ and 23.22 g of di-tert-butyl dicarbonate (di-t-BOC) were added as a catalyst and stirred for 5 minutes. Then, after the temperature was raised to room temperature, stirring was continued for 6 to 7 hours. The reaction mixture was filtered to remove Na ₂ CO ₃ , and 200 mL of ethanol was added to the reaction mixture, which was concentrated under reduced pressure, and diluted. The polar solvent in ethanol was removed using brine, and finally, a solution obtained by removing the moisture with anhydrous magnesium sulfate (anhydrous MgSO ₄ ) was concentrated under reduced pressure to prepare a reaction product containing a small amount of impurities. Then ethanol was used as the recrystallization solvent to obtain a white solid.

3,5-bis (tert- butoxycarbonylamino) benzyl cinnamate [3,5-Bis (tert - butoxycarbonylamino ) benzyl cinnamate] Preparation (Compound 3):

6 g of Compound 2 was added to a 500 mL round bottom flask equipped with an ice bath, dissolved in 250 mL methylene chloride, and 3.5 g of cinnamoyl chloride was added thereto and stirred. After slowly injecting 4 g of triethylamine (TEA) at 0 ° C., the temperature was raised to room temperature and stirring was continued for 12 hours. The reaction mixture was brine, and the polar solvent in MC was removed. Finally, a solution obtained by removing water with anhydrous magnesium sulfate (anhydrous MgSO ₄ ) was concentrated under reduced pressure to prepare a reaction product containing trace impurities. Then purified by column chromatography (ethanol: hexane = 1: 4) to give a white solid.

Scheme 4

3,5 -diamino benzyl cinnamate [3,5- Diamino benzyl cinnamate ( DABC )] Preparation (Compound 4):

6 g of Compound 3 was added to a 500 mL round bottom flask, dissolved in 200 mL methylene chloride, and 100 mL of trifluoroacetic acid (CF ₃ COOH) was added thereto, followed by stirring at room temperature for 4 hours. The reaction mixture was concentrated under reduced pressure to remove volatiles and diluted with 250 mL MC. The diluted reaction mixture was neutralized with NaHCO _3, and then the brine was used to remove the polar solvent in MC. Finally, the solution which had been removed with anhydrous magnesium sulfate (anhydrous MgSO ₄ ) under reduced pressure was concentrated under reduced pressure. Was prepared. Subsequent purification by column chromatography (ethanol: hexane = 3: 2) afforded a yellow liquid compound.

2 is nuclear magnetic resonance (H-NMR) analysis data of 3,5-diamino benzyl cinnamate.

Scheme 5

[ Example  One] KPI Manufacture of -1

2.6423 g (0.01 mol) of 5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA] and 2.6812 g (0.01 mol) of compound 4 (DABC) Was prepared in a 50 mL round bottom flask, and 21.294 g of m-cresol was added as a polymerization solvent to completely dissolve both monomers. Solid content ratio was set to 20 wt% in the reaction solvent of the monomer. The reaction was slowly heated to 70 ° C. over 2 hours, maintained at 70 ° C. for 2 hours, and the temperature was raised over 2 hours from 70 ° C. to 130 ° C. The reaction was sent at 130 ° C. for 10 hours and the reaction was terminated. The viscosity of the final reaction solution was measured at 1100 cps. The terminated reaction mixture was precipitated in excess methanol and filtered under reduced pressure to remove the solvent and residual solvent in the oven to obtain the final polymer.

Scheme 6

[ Example  2] KPI -One/ MDA Copolymer  [ KPIC -5] manufacturing, DOCDA (10) / DABC (5) / MDA (5)

5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA] 3.435 g (0.013 mol), compound 4 (DABC) 1.743 g (0.0065 mol) 1.289 g (0.0065 mol) of 4,4'-methylenedibenzenamine (MDA) was prepared in a 50 mL round bottom flask, and 25.866 g of m-cresol was added as a polymerization solvent. Dissolve both monomers completely. Solid content ratio was set to 20 wt% in the reaction solvent of the monomer. The reaction was slowly heated to 70 ° C. over 2 hours, maintained at 70 ° C. for 2 hours, and the temperature was raised over 2 hours from 70 ° C. to 130 ° C. The reaction was sent at 130 ° C. for 10 hours and the reaction was terminated. The viscosity of the final reaction solution was measured at 2,850 cps. The terminated reaction mixture was precipitated in excess methanol and filtered under reduced pressure to remove the solvent and residual solvent in the oven to obtain the final polymer.

Scheme 7

[ Example  3] KPI -One/ MDA Copolymer  [ KPIC -3] manufacturing; DOCDA (10) / DABC (3) / MDA (7)

5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA] 3.435 g (0.013 mol), compound 4 (DABC) 1.046 g (0.0039 mol) 1.804 g (0.0091 mol) of 4,4′-methylenedibenzeneamine (MDA) was prepared in a 50 mL round bottom flask, and 25.140 g of m-cresol was added as a polymerization solvent to completely dissolve both monomers. Solid content ratio was set to 20 wt% in the reaction solvent of the monomer. The reaction was slowly heated to 70 ° C. over 2 hours, maintained at 70 ° C. for 2 hours, and the temperature was raised over 2 hours from 70 ° C. to 130 ° C. The reaction was sent at 130 ° C. for 10 hours and the reaction was terminated. The viscosity of the final reaction solution was measured at 3,100 cps. The terminated reaction mixture was precipitated in excess methanol and filtered under reduced pressure to remove the solvent and residual solvent in the oven to obtain the final polymer.

[ Example  4] KPI -One/ MDA Copolymer  [ KPIC -1] manufacture, DOCDA (10) / DABC (One)/ MDA (9)

Solid 5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA] 3.435 g (0.013 mol), compound 4 (DABC) 0.349 g (0.0013 mol ), 2,320 g (0.0117 mol) of 4,4'-methylenedibenzeneamine (MDA) was prepared in a 50 mL round bottom flask, and 24.413 g of m-cresol was added as a polymerization solvent to completely dissolve both monomers. Solid content ratio was set to 20 wt% in the reaction solvent of the monomer. The reaction was slowly heated to 70 ° C. over 2 hours, maintained at 70 ° C. for 2 hours, and the temperature was raised over 2 hours from 70 ° C. to 130 ° C. The reaction was sent at 130 ° C. for 4 hours and the reaction was terminated. The viscosity of the final reaction solution was measured at 6,400 cps. The terminated reaction mixture was precipitated in excess methanol and filtered under reduced pressure to remove the solvent and residual solvent in the oven to obtain the final polymer.

[ Example  5] KPI -1 thin film production and Photocuring

The organic insulator thin film was prepared by spin coating at a speed of about 3000 rpm using a solution in which the prepared KPI-1 polymer was dissolved at a concentration of 12 wt% in a γ-butyrolactone solvent. The thin film was adjusted to 300 nm in thickness and subjected to soft baking (90 ° C., 10 minutes) to remove residual solvent. UV light of 1000 mJ to 1500mJ was irradiated for the photocuring of the thin film, and finally an organic insulator thin film was finally photocured by hard baking for 10 minutes at 90 ° C. and 30 minutes at 160 ° C. after UV irradiation. It was. 1 shows the photocuring mechanism and the chemical structure of the photocured polymer thin film.

[ Example  6] KPIC -1 thin film production and Photocuring

The organic insulator thin film was prepared by spin coating at a speed of about 3000 rpm using a solution in which the prepared KPIC-1 polymer was dissolved at a concentration of 12 wt% in a γ-butylarolactone solvent. The prepared thin film was adjusted to 300 nm in thickness and subjected to soft baking (90 ° C., 10 minutes) to remove residual solvent. UV light of 1000 mJ to 1500mJ was irradiated for the photocuring of the thin film. After UV irradiation, the organic insulator thin film was finally cured by hard baking for 10 minutes at 90 ° C and 30 minutes at 160 ° C. Prepared.

[ Comparative example  One] Not photocured  Not KPI Preparation of -1 Thin Film

The organic insulator thin film was prepared by spin coating at a speed of about 3000 rpm using a solution in which KPI-1 polymer was dissolved at a concentration of 12 wt% in a γ-butylolactone solvent. The thin film was adjusted to a thickness of 300 nm and subjected to soft baking (90 ° C., 10 minutes) to remove residual solvents, and then hardly baked at 160 ° C. for 30 minutes. An insulator thin film was prepared.

[ Comparative example  2] Not photocured  Not KPIC Preparation of -1 Thin Film

An organic insulator thin film was prepared by spin coating at a speed of about 3000 rpm using a solution in which KPIC-1 polymer was dissolved in a γ-butylolactone solvent at a concentration of 12 wt%. The thickness of the prepared thin film was adjusted to 300 nm, and after soft baking (90 ° C., 10 minutes) to remove residual solvent, KPIC-1 organic insulator was not finally cured by hard baking at 160 ° C. for 30 minutes. A thin film was prepared.

[ Example  7] Characterization of the manufactured organic insulator thin film

(1) for organic solvents Surface roughness  evaluation:

General organic solvents (cyclohexanone, chloroform, N, N-dimethylformamide (DMF), n-methylpyrroli to evaluate the chemical resistance of organic insulator thin film which plays an important role in the manufacture of organic thin film transistor through solution process) After the thin film was dipped into ton (NMP) and a mixed solvent thereof, the surface roughness of the thin film was measured and evaluated. As a result of the cyclohexanone, chloroform or NMP solvent, KPI-1 of Comparative Example 1 was completely dissolved in the solvent, and the KPI-1 of Example 5 photocured by UV irradiation was completely surface in the organic solvent. Was not damaged. As a result of detailed analysis of the insulating thin film surface of Example 5 through atomic force microscopy (AFM), the RMS value, which is the surface roughness property, was excellent even after the organic solvent treatment. After dipping the thin film of KPIC-1 of Example 6 into an organic solvent, the surface thereof was analyzed, and almost the same value as KPI-1 of Example 5 was obtained.

KPI-1 and KPIC-1 of the present invention showed excellent solubility in general organic solvents, and the organic insulator thin film could be formed by photocuring at 150 to 160 ° C, and the insulating thin film formed by photocuring was dissolved again in the organic solvent. And maintained the insulating thin film.

(2) Leakage current evaluation of insulating thin film:

KPI-1 and KPIC-1 organic insulator thin films were compared before and after photo curing to evaluate leakage current, the most important characteristic. Devices of an electrode-dielectric-electrode (metal-insulator-metal (MIM)) structure were fabricated, respectively, and the conditions for preparing the dielectrics were the conditions for manufacturing the thin films of Comparative Examples 1 and 2, which were not photocured, and Example 5, which were photocured. And a thin film was prepared under the conditions of 6. Patterned indium-tin-oxide (ITO) electrodes were used as the lower electrodes, and gold (Au) was deposited using a shadow mask as the upper electrodes, and the thickness of the organic insulating layer was set to 300 nm.

3 shows the leakage current density of KPI-1 before and after photo curing. In the case of KPI-1, the leakage current density was 5.6 × 10 ^-10 A / cm ² at 2MV / cm before light curing, but improved to 1.1 × 10 ^-11 after light curing (1000 mJ energy irradiation), especially 3.0 MV. Excellent breakdown voltage of more than / cm. The dielectric breakdown voltage of 3MV / cm or more of photo-cured KPI-1 is not limited to organic polymers (1 ~ 2 MV / cm) such as polyvinyl alcohol (PVA), polyvinylphenol (PVP), etc. Compared with the improved value, this can be interpreted that the packing density of the polymer film due to photocuring between polymer chains is increased.

4 shows the leakage current density of KPIC-1 before and after photo curing. In the case of KPIC-1, the leakage current density was 1.2 × 10 ^-10 A / cm ² at 2MV / cm before light curing, but improved to 1.0 × 10 ^-11 after light curing (1000 mJ energy irradiation), especially 3.0 MV. Excellent breakdown voltage of more than / cm. The dielectric breakdown voltage of 3MV / cm or more of photocured KPIC-1 is not limited to organic polymers (1 ~ 2 MV / cm) such as polyvinyl alcohol (PVA) and polyvinylphenol (PVP), which are widely used as conventional organic insulators. It is a better value, which can be interpreted as an increase in packing density of polymer membranes by photocuring between polymer chains.

[ Example  8] Fabrication and Characterization of Organic Thin Film Transistor

The present invention fabricated an organic thin film transistor using the polyimide organic insulator thin film of the present invention capable of low temperature process and photocuring and measured its characteristics. As the organic active layer, pentacene, which is widely used in organic thin film transistors and has a relatively good performance, was used. Since the organic insulator of the present invention has a process temperature of 150 to 160 ° C, a plastic substrate such as polyethersulfone and glass are used.

The device structure of the organic thin film transistor is in the form of a top contact, and the method of fabricating the device is as follows. Substrate cleanliness is one of the most important factors when manufacturing electronic devices, so if the substrate is glass, ultrasonic cleaning with detergent, distilled water, acetone, and isopropyl alcohol was used, and then dried sufficiently in an oven. It was used as it was only after detaching the protective film without a separate washing process.

Gold (Au) was thermally vacuum deposited on a well cleaned substrate in a vacuum of 1 × 10 ⁻⁶ torr using a shadow mask to form a 2 mm wide gate electrode having a thickness of 40 nm. The low temperature process of the present invention and the photocurable polyimide organic insulators (KPI-1 and KPIC-1) were each spin-coated to a thickness of 300 nm, dried at 90 ° C. for 10 minutes, and then photocured through UV irradiation. Finally, in order to completely remove the residual solvent and finally dried for 30 minutes at a temperature of 160 ℃ to obtain a photo-cured polyimide organic insulator thin film.

As a comparative example, in order to confirm the effect of the introduction of the photocuring machine, the organic insulator thin film of KPI-1 and KPIC-1 which omitted only photocuring (UV irradiation) in the manufacturing process of the organic thin film transistor including KPI-1 and KPIC-1. Was prepared.

Pentacene, an organic active layer, was deposited to a thickness of 50 nm on the organic insulator thin films prepared as described above using thermal vacuum deposition in a vacuum of 1 × 10 ⁻⁶ torr. At this time, the temperature of the substrate which greatly affects the crystallization of pentacene was kept constant at 90 ℃. Finally, gold was deposited to a thickness of 50 nm in the same manner as gate deposition to form source and drain electrodes. Bottom-contact devices were fabricated by changing the order of formation of pentacene and source and drain electrodes. The characteristics of the device fabricated as described above were measured in the saturation region by measuring the drain voltage-drain current according to the gate voltage and the gate voltage-drain current curve according to the drain voltage by using the E5272 device of Agilent Technology. Various characteristics were evaluated using the current and voltage equations.

[Equation 1]

와 V_gs 의 그래프로부터 I_ds 가 0인 게이트 전압으로 결정되고 전계효과 전하이동도는

와 V_gs의 그래프의 기울기로부터 산출하였다. V _T Is the threshold voltage, V _gs is the applied gate voltage, μ is the field effect charge mobility, W and L are the width and length of the channel, and C is the capacitance of the insulating film. Threshold voltage

From the graphs of V _gs and V _gs , we determine the gate voltage with I _ds 0 and the field effect charge mobility

It was computed from the slope of the graph of and V _gs .

FIG. 5 shows the current-voltage characteristics of the organic thin film transistor including the photocured KPI-1 prepared in Example 5 and Comparative Example 1 and the non-photocured KPI-1 as the organic insulator thin film. The on-current values of KPI-1 before and after photo curing showed similar values from 1.14 × 10 ⁻⁵ A to 1.85 × 10 ⁻⁵ A. However, the off current was significantly improved from 6.26 × 10 ^-7 A to 8.75 × 10 ^-11 A, which can be interpreted as an improvement in insulation due to an increase in packing density of the KPI-1 thin film by photocuring. The ratio of lighting current to flashing current (Ion / Ioff), which is important for transistor performance, has also been significantly improved from 2.95 × 10 to 1.30 × 10 ⁵ . For devices containing photocured KPI-1, the field mobility was about 0.12 cm ² / Vs.

FIG. 6 shows current-voltage characteristics of organic thin film transistors including photocured KPIC-1 and KPIC-1 not photocured as an organic insulator thin film prepared in Example 6 and Comparative Example 2. FIG. The on current value of KPI-1 before and after photocuring increased to 1.63 × 10 ^-5 A before photocuring and 2.69 × 10 ^-5 A after photocuring. The off current was 2.91 × 10 ⁻¹¹ A before photocuring and 3.70 × 10 ⁻¹¹ A after photocuring, showing similar values. The field mobility characteristics were improved to 0.20 cm ² / Vs before light curing and 0.24 cm ² / Vs after light curing.

In the case of KPI-1 and KPIC-1, the organic insulating thin film showed excellent chemical resistance after photo curing. In the case of KPIC-1, which has improved molecular weight compared to KPI-1 through the copolymerization method, the mobility characteristics of the organic thin film transistor device This is about twice as much. In the case of KPI-1 and KPIC-1 prepared using the photocurable diamine derivative of Formula 3 or Formula 4, it has the advantage that it can be patterned through photocuring using a photomask, and polymer chains by photocuring Curing of resulted in improving the insulating properties of the organic insulating thin film. The newly prepared photocurable DABC monomers can be used to prepare organic insulating polymers capable of photocuring and low temperature processing through polymerization with various dicarboxylic dianhydrides and diamine derivatives.

1 is a curing mechanism by photo curing of the novel organic insulator of the present invention,

2 is a figure confirmed through the 3,5-diamino-benzyl cinnamate the ¹ H- nuclear magnetic resonance analysis ^{(DABC) (1 H-NMR} ) of Preparation 1,

3 is a leakage current density before and after photocuring of the organic insulator (KPI-1) of Example 5 and Comparative Example 1,

4 is a leakage current density before and after photocuring of the organic insulator (KPIC-1) of Example 6 and Comparative Example 2,

5 is a current-voltage (I-V) curve of the organic thin film transistor element before and after photocuring of the organic insulator (KPI-1) of Example 5 and Comparative Example 1,

6 is a current-voltage (I-V) curve of the organic thin film transistor element before and after photocuring of the organic insulator (KPIC-1) of Example 6 and Comparative Example 2. FIG.

Claims (19)

A polyimide for one organic thin film transistor organic insulator selected from Formula 1, Formula 2 and Formula 3. [Formula 1]

[Formula 2]

(3)

In Formula 1, Formula 2 and Formula 3,

Is

,

,

,

,

,

,

,

,

,

,

And

At least one tetravalent group selected from the group consisting of:

Is

,

,

,

,

,

,

,

,

And

At least one 2-group selected from the group consisting of; q is an integer from 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C1-C10 alkyl, cyano or halogen substituents; The sum of m, n and l is an integer from 10 to 3,000 (m contains 0). The method of claim 1, A polyimide for organic thin film transistor organic insulators having a mass average molecular weight of the polyimide in the range of 5,000 to 1,000,000 g / mol. The method of claim 1, Polyimide for organic thin film transistor organic insulator having an intrinsic viscosity of the polyimide in the range of 0.1 to 1.5 dL / g. The method of claim 1, The polyimide for organic thin film transistor organic insulator whose insulating thin film formation temperature of the said polyimide is 100-300 degreeC. A diamine derivative selected from the following formula (4) or (5) for the preparation of the polyimide for organic thin film transistor organic insulator of claim 1. [Formula 4]

[Chemical Formula 5]

In Chemical Formulas 4 and 5, q is an integer of 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C 1 -C 10 alkyl, cyano or halogen substituents. The method of claim 5, The diamine derivatives include 3,5-diamino benzyl cinnamate, 3-naphthalen-2-yl-acrylic acid-3,5-diamino-benzyl ether, 3-biphenyl-4-yl-acrylic acid-3,5- Diamine derivatives selected from diamino-benzyl ethers and derivatives thereof. A method for preparing a polyimide prepared by polymerization of at least one diamine and tetracarboxylic dianhydride selected from the following Chemical Formulas 4, 5, and 6, wherein the polyimide is selected from Formula 4 or Formula 5 Method for producing a polyimide, characterized in that it comprises. [Formula 4]

[Chemical Formula 5]

[Formula 6]

[In Formula 4 to Formula 6,

Is

,

,

,

,

,

,

,

,

And

At least one 2-group selected from the group consisting of; q is an integer from 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, alkyl of C1-C10, cyano or halogen.] The method of claim 7, wherein The polyimide is a method for producing a polyimide is any one selected from the following formula (1), (2) and (3). [Formula 1]

[Formula 2]

(3)

In Formula 1, Formula 2 and Formula 3,

Is

,

,

,

,

,

,

,

,

,

,

And

At least one tetravalent group selected from the group consisting of:

Is

,

,

,

,

,

,

,

,

And

At least one 2-group selected from the group consisting of; q is an integer from 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C1-C10 alkyl, cyano or halogen substituents; The sum of m, n and l is an integer from 10 to 3,000 (m contains 0). The method of claim 7, wherein The tetracarboxylic dianhydride monomers are 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 5- (2,5-dioxotetra Hydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuryl-3-yl) -tetraline-1,2-dicarboxylic acid One or two or more aliphatic dianhydrides selected from anhydrides and bicyclooctene-2,3,5,6-tetracarboxylic dianhydrides; Or one or two or more aromatic tetracarboxylic dianhydrides selected from pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, oxydiphthalic dianhydride, nonphthalic dianhydride, and hexafluoroisopropylidenediphthalic dianhydride. The manufacturing method of polyimide to be. The method of claim 7, wherein The diamine derivative of Chemical Formula 6 may be para-phenylenediamine, meta-phenylenediamine, 4,4-oxydianiline, 4,4-methylenedianiline, 2,2-bisaminophenylhexafuluropropane, metabis Aminophenoxydiphenylsulfone, parabisaminophenoxydiphenylsulfone, 1,4-bisaminophenoxybenzene, 1,3-bisaminophenoxybenzene, 2,2-bisaminophenoxyphenylpropane and 2,2-bis A method for producing a polyimide, which is one or two or more aromatic diamines selected from aminophenoxyphenylhexafuluropropane. The method of claim 7, wherein The polymerization solvent is one or two selected from dimethylacetamide, dimethylformamide, N -methyl-2-pyrrolidone, acetone, ethyl acetate, meta-cresol, tetrahydrofuran, chloroform and gamma-butyrolactone. The manufacturing method of the polyimide made into the above solvent. The method of claim 7, wherein Solid content ratio with respect to a polymerization reaction is 5-40 weight% of the manufacturing method of polyimide. a) dissolving 3,5-dinitro benzyl alcohol to reduce the catalyst and under reduced pressure to obtain a solid of 3,5-diamino benzyl alcohol; b) dissolution of 3,5-diamino benzyl alcohol and di-tert-butyl dicarbonate (t-BOC) under a catalyst to react with di-tert-butyl-5- (hydroxymethyl) -1,3-phenylene Obtaining a dicarbamate solid; c) dissolving di-tert-butyl-5- (hydroxymethyl) -1,3-phenylenedicarbamate and adding a halide of Formula 7 or Formula 8 to obtain a compound of Formula 9 or Formula 10 Making; And d) dissolving a compound of Formula 9 or Formula 10 and adding trifluoroacetic acid to obtain a diamine derivative of Formula 4 or Formula 5 below; Method for producing a diamine derivative represented by the following formula (4) or (5) comprising a. [Formula 4]

[Chemical Formula 5]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

In Chemical Formulas 6 to 9, q is an integer of 0 to 10; X ¹ , X ² , X ³ , X ⁴ and X ⁵ are independently of each other hydrogen, C 1 -C 10 alkyl, cyano or halogen substituents. An organic thin film transistor composed of a gate electrode, an organic insulating film, an organic active layer, a source / drain electrode, and a protective layer on an upper substrate, wherein the organic insulating film is any one selected from claims 1 to 4. An organic thin film transistor which is supposed to be a polyimide of one term. The method of claim 14, The polyimide is an organic thin film transistor to form an organic insulating film by a method selected from the group consisting of a spin coating method, an inkjet printing method and a dipping method. The method of claim 14, The organic insulating film has a thickness of 30 to 900 nm range of the organic thin film transistor. The method of claim 14, The organic active layer is composed of pentacene, metal phthalocyanine, polythiophene, polyphenylenevinylene, C ₆₀ , phenylene tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, fluorinated phthalocyanine and derivatives thereof Organic thin film transistor selected from the group. The method of claim 14, An organic thin film transistor having an electric field mobility of 0.01 to 10 cm 2 / Vs. A display device using the organic thin film transistor of any one of claims 14 to 18.

Images