KR101856563B1 - Organic thin film transistor having liquid crystalline properties and method for fabricating the same - Google Patents

Abstract

According to an aspect of the present invention, there is provided a liquid crystal organic thin film transistor comprising a substrate, a gate electrode, a gate insulating layer, an active layer, and an electrode material layer sequentially, wherein the gate insulating layer is a vertically photo- Mate based polymer and a method of manufacturing the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal organic thin film transistor and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a liquid crystal organic thin film transistor and a manufacturing method thereof.

Along with the development of information and communication technology, there is an increasing demand for small, light and easy-to-use information communication devices and devices and electronic materials that enable such information communication devices. Among them, organic thin film transistors (OTFTs) are simpler in manufacturing process than conventional organic thin film transistors using amorphous silicon and polysilicon, and have excellent compatibility with plastic substrates for implementing flexible displays, and many studies have been made recently.

The major physical properties for evaluating the performance of the organic thin film transistor are the charge mobility and the on / off ratio. In particular, the charge mobility is determined by the kind of the semiconductor material, the thin film forming method (structure and morphology) Voltage and so on.

1 is a sectional view showing a layered structure of a general organic thin film transistor composed of a substrate 11, a gate electrode 16, a gate insulating layer 12, an active layer 13, and electrode material layers 14 and 15. The semiconductor material constituting the active layer may be divided into a low-molecular organic semiconductor and a high-molecular organic semiconductor depending on the molecular weight, and may be divided into an n-type organic semiconductor or a p-type organic semiconductor depending on whether electrons or holes are transmitted.

The low molecular weight organic semiconductors are easy to purify and can remove most impurities, so they have excellent charge mobility but can not be spin coated or printed, so that a thin film must be produced through vacuum deposition, which complicates the process. On the other hand, polymer organic semiconductors are difficult to purify with high purity, but have excellent heat resistance and can be spin coated or printed, making them suitable for mass production.

On the other hand, various studies have been conducted to improve the charge mobility of the polymer organic semiconductor material. Korean Patent No. 10-0668763, for example, has attempted to improve the charge mobility due to the alignment of molecules by introducing liquid crystalline organic polymer having excellent thermal stability. However, the arrangement of the liquid crystalline polymer is changed from the electrochemical property of the molecule itself It is difficult to improve the charge mobility to a certain level or more.

Korean Patent Registration No. 10-1096695 discloses that alignment of liquid crystal molecules can be precisely controlled by using a photo alignment layer having a cinnamide group, but this is provided separately from an organic thin film transistor among liquid crystal display elements And it is not designed to affect the orientation and physical properties of the semiconductor layer of the organic thin film transistor, that is, the active layer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic thin film transistor, in which a liquid crystalline organic polymer is introduced into an active layer of an organic thin film transistor, its orientation is precisely controlled, An organic thin film transistor excellent in thermal stability and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a liquid crystal organic thin film transistor comprising a substrate, a gate electrode, a gate insulating layer, an active layer, and an electrode material layer sequentially, wherein the gate insulating layer is a vertically photo- Mate based polymer is provided.

In one embodiment, the active layer may include a thiophene-based polymer.

In one embodiment, the thiophene-based polymer may be represented by the following formula (1).

≪ Formula 1 >

,

, 및

로 이루어진 군에서 선택된 하나이고, n이 1 내지 10,000의 정수이다.Wherein R ₁ and R ₂ are, independently of one another, a Cl to C20 alkyl group, and X is

,

, And

And n is an integer of 1 to 10,000.

In one embodiment, the thiophene-based polymer may be poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2-b] thiophene).

In one embodiment, the cinnamate-based polymer may be selected from the group consisting of polyvinylcinnamate, polyvinylmethoxycinnamate, polyvinylfluorinated cinnamate, and polysiloxane cinnamate.

In one embodiment, the cinnamate-based polymer may be polyvinylcinnamate.

In one embodiment, the polyvinyl cinnamate may have a weight average molecular weight (Mw) of 50,000 to 500,000.

According to another aspect of the present invention, there is provided a method for preparing a polymer electrolyte membrane, comprising: (a) dissolving a cinnamate-based polymer and a thiophene-based polymer in a first solvent and a second solvent, respectively; (b) coating the first solution on a substrate provided with a gate electrode to form a gate insulating layer; (c) vertically aligning the cinnamate-based polymer to the UV by irradiating the gate insulating layer with linearly polarized UV light; (d) coating the second solution on the photo-aligned gate insulating layer to form an active layer; (e) annealing the active layer at 100 to 300 캜; And (f) depositing gold on the active layer to form a source electrode and a drain electrode.

In one embodiment, the thiophene-based polymer may be represented by the following formula (1).

≪ Formula 1 >

,

, 및

로 이루어진 군에서 선택된 하나이고, n이 1 내지 10,000의 정수이다.Wherein R ₁ and R ₂ are, independently of one another, a Cl to C20 alkyl group, and X is

,

, And

And n is an integer of 1 to 10,000.

In one embodiment, the thiophene-based polymer may be poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2-b] thiophene).

In one embodiment, the first and second solvents may each independently be at least one selected from the group consisting of chloroethane, dichloroethane, chlorobenzene, dichlorobenzene, and trichlorobenzene.

In one embodiment, in the steps (b) and (d), the coating may be performed by spin coating.

In one embodiment, the intensity of the linearly polarized UV in step (c) may be 5 to 50 J / cm ² .

The liquid crystalline organic thin film transistor according to one aspect of the present invention includes a cinnamate-based polymer having a basic insulating property and a photo orientation in a predetermined direction, the gate insulating layer being located below the active layer including the liquid crystalline organic polymer, The charge mobility can be greatly improved by precisely controlling the orientation of the active layer.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal organic thin film transistor, including the steps of performing a photo alignment process and an annealing process without a separate purification process, thereby improving the productivity of the high performance organic thin film transistor.

It should be understood that the effects of the present invention are not limited to the effects described above, but include all effects that can be deduced from the description of the invention or the composition of the invention set forth in the claims.

1 is a cross-sectional view showing a layered structure of a general organic thin film transistor.
Figure 2 shows UV / Vis spectra and cycloaddition reactions of polyvinyl cinnamate according to one embodiment of the present invention.
3 is a thermogravimetric analysis (TGA) result and an AFM image of a polyvinylcinnamate according to one embodiment of the present invention.
Figure 4 shows the electrostatic capacity and leakage current density of polyvinyl cinnamate according to one embodiment of the present invention.
Figure 5 shows the UV / Vis spectra of poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2-b] thiophene) according to one embodiment of the invention and comparative example .
6 shows transfer characteristics of an organic thin film transistor according to an embodiment and a comparative example of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" . Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Liquid crystal property Organic thin film  transistor

According to an aspect of the present invention, there is provided a liquid crystal organic thin film transistor including a substrate, a gate electrode, a gate insulating layer, an active layer, and an electrode material layer sequentially, wherein the gate insulating layer is a linear polarized UV The present invention provides a liquid crystalline organic thin film transistor including a cinnamate-based polymer vertically aligned with respect to a liquid crystal polymer (hereinafter, " LPUV ").

As used herein, the term "vertical" refers to an angle formed by two lines or faces of 90 degrees, or an average value of angles formed by a plurality of lines or faces of 90 degrees, And the like. As used herein, the term "parallel ", as used herein, refers to the case where the angle formed by two lines or faces is 0 DEG, or the average value of the angle formed by a plurality of lines or faces is 0 DEG, As shown in Fig.

The liquid crystal organic thin film transistor may be applied to a liquid crystal display device which is a kind of flat panel display. The liquid crystal display element is required to have a function as a display element such as light transmittance, response time, viewing angle, contrast, and the like. Since such a function is determined according to the arrangement characteristic of the liquid crystal molecules of the liquid crystal display element, it is important to control the alignment of the liquid crystal molecules uniformly Do.

As a method for uniformly orienting the liquid crystal molecules, a method of rubbing a surface of a film or film made of an organic polymer material with a special type of cloth can be mentioned. However, while rubbing is simple in process, there is a problem that the alignment film can be contaminated by dust adhering to a special type cloth used between processes, and compatibility is different depending on the material of the alignment film.

In order to solve the problems of the rubbing method, research and development of a rubbing free treatment have been carried out, and a photo alignment method has been attracting attention. In the related art, the cinnamate-based polymer is a polymer having a cinnamoyl group in the side chain, and may be selected from the group consisting of polyvinylcinnamate, polyvinylmethoxycinnamate, polyvinylfluorinated cinnamate, and polysiloxane cinnamate , Each of these structures may be represented by the following formula (2).

(2)

The chemical structure of the cinnamate-based polymer includes a main chain (backbone) serving to align the liquid crystal molecules in one direction by a photoreaction and a side chain serving to form and improve a pretilt angle Can be distinguished. For example, the cinnamate-based polymer may be polyvinyl cinnamate (hereinafter referred to as 'PVCN'). The weight average molecular weight (Mw) of the PVCN may be 50,000 to 500,000, and preferably 100,000 to 300,000.

Referring to FIG. 2 (b), when the PVCN is irradiated with LPUV, the cinnamoyl group, which is the side chain of the PVCN, is cycled by [2 + 2] cycles by LPUV to form cyclobutane And thus the PVCN molecules can be arranged in a direction perpendicular to the LPUV.

Figure 2 (a) shows the UV / Vis spectrum of a PVCN film (thickness: 400 nm) optically oriented with LPUV. Referring to FIG. 2 (a), it can be seen that the gate insulating layer includes PVCN vertically oriented as well as parallel oriented PVCN to LPUV, and both have a distinct peak corresponding to the cinnamoyl group of PVCN at a wavelength of 275 nm Is observed. Also, the dichroic ratio (A _⊥ / A _// ) at 275 nm is 1.1, and the vertically oriented PVCN is relatively dominant as compared with the horizontally oriented PVCN. As used herein, the term "two-color ratio" refers to the absorption intensity (A _// ) of a horizontally oriented molecule or polymer for LPUV in a UV / Vis spectrum for a given material. It means the ratio of the absorption intensity (a _⊥).

However, the dichroic ratio is a value measured over the entire area of the PVCN film. In a surface region corresponding to 10 to 20% of the total thickness from the surface of the film, PVCN has a more uniform orientation in the vertical direction with respect to LPUV Therefore, it is possible to impart a certain orientation to the material forming the active layer.

3 (a), the weight loss of optically oriented PVCN under nitrogen atmosphere was less than 1 wt% and less than 5 wt% at 220 ° C and 285 ° C, respectively, and the optically oriented PVCN film was found to be in an annealing step It has good thermal stability to withstand the high temperature conditions of < RTI ID = 0.0 > 3 (b), the root mean square (RMS) surface roughness of photo-oriented PVCN was measured to be 0.18, which is similar to that of smooth SiO ₂ (~ 0.4 nm) .

On the other hand, the surface tension of the PVCN film can be measured by the contact angle of water and diiodomethane, and the results are shown in Table 1 below.

division Contact angle (°) Surface energy
(mN / m) Surface roughness
RMS (nm) water Diiodomethane Untreated PVCN 77.7 35.3 42.3 0.13 About LPUV
Vertical photoinduced PVCN 77.7 35.3 42.3 0.18 About LPUV
Parallel photo-oriented PVCN 77.9 35.7 42.2 0.14

Referring to Table 1 above, the photo-aligned PVCN film can be easily and uniformly produced regardless of the direction of the LPUV, since the contact angle and the surface tension (surface energy) of the PVCN of the vertical and horizontal photo-aligned to the LPUV are almost similar .

FIG. 4 shows the results of measuring the electrostatic capacity, leakage current density, and breakdown voltage of the photo-oriented PVCN film using the MIM capacitor structure. First, referring to Figure 4 (a), and at 1kHz a capacitance and dielectric constant of the optical film respectively oriented PVCN 7.6nF / cm ² and 3.35, the capacitance does not change substantially from 100Hz to 1MHz, in which the film It means that there is almost no mobile impurity.

Referring to Fig. 4 (b), the optically oriented PVCN film has a stable gate leakage current density exceeding 10 ^-7 A / cm < ² > in a breakdown field exceeding 2.5 MV / cm. The low leakage current density and high breakdown voltage of the optically oriented PVCN are analyzed to be due to the crosslinking effect due to polymerization and curing. In addition, since the migration of the leakage current mainly occurs through impurities or defects, the optically oriented PVCN film having a low leakage current density is suitable as a gate insulation layer of the organic thin film transistor.

The active layer may include a thiophene-based polymer, and the thiophene-based polymer may be represented by the following formula (1).

≪ Formula 1 >

,

, 및

로 이루어진 군에서 선택된 하나이고, n이 1 내지 10,000의 정수이다. 상기

,

, 및

가 상기 화학식 1의 구조 내에서 C-C 결합을 형성하도록 포함될 수 있다. 즉, 상기 X 중 황(S)을 제외한 임의의 탄소가 상기 X의 양단에 위치한 작용기 치환된 티오펜 중 고리 부분에 위치한 임의의 탄소와 결합될 수 있다. 상기 화학식 1로 표시될 수 있는 티오펜계 고분자는, 예를 들어, 폴리(2,5-비스(3-도데실티오펜-2-일)티에노[3,2-b]티오펜)(이하, 'PBTTT')일 수 있다.Wherein R ₁ and R ₂ are, independently of one another, a Cl to C20 alkyl group, and X is

,

, And

And n is an integer of 1 to 10,000. remind

,

, And

May be included to form a CC bond within the structure of Formula 1 above. That is, any carbon other than the X sulfur (S) may be combined with any carbon located in the ring portion of the functional group substituted thiophene located at both ends of the X. The thiophene-based polymer represented by Formula 1 may be, for example, a poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2- , 'PBTTT').

The PBTTT is a stable p-type organic semiconductor in the air having a low HOMO energy level, and has a Smectic liquid crystal phase at 120 to 180 ° C due to the structural characteristics of the main chain being rigid and the side chains being flexible. Since the PBTTT is a liquid crystalline polymer, it can have a uniform orientation on the optically oriented PVCN film.

Specifically, the optically oriented PVCN film can have a more uniform orientation in the direction perpendicular to the LPUV in the region in contact with the active layer, that is, the surface region, so that PBTTT, which is a kind of liquid crystalline polymer, .

The vertical orientation imparted to the PBTTT by contact with the optically oriented PVCN film can be further enhanced by the annealing process described below. For example, the dichroic ratio (A _⊥ / A _// ) of the PBTTT may be 1.2 to 1.5 because liquid crystal molecules vertically aligned with respect to the LPUV in the active layer are more dominant than the gate insulating layer It means that it exists.

Liquid crystal property Organic thin film  Method of manufacturing a transistor

According to another aspect of the present invention, there is provided a method for preparing a polymer electrolyte membrane, comprising: (a) dissolving a cinnamate-based polymer and a thiophene-based polymer in a first solvent and a second solvent, respectively; (b) coating the first solution on a substrate provided with a gate electrode to form a gate insulating layer; (c) vertically aligning the cinnamate-based polymer with the UV by irradiating linearly polarized UV (hereinafter, referred to as LPUV) to the gate insulating layer; (d) coating the second solution on the photo-aligned gate insulating layer to form an active layer; (e) annealing the active layer at 100 to 300 캜; And (f) depositing gold on the active layer to form a source electrode and a drain electrode.

The nature of the cinnamate- and thiophene-based polymer and the properties of the gate insulating layer and the active layer formed therefrom, and the action and effect of the contact and bonding between the gate insulating layer and the active layer are as described above.

In the step (a), each of the cinnamate-based and thiophene-based polymers may be dissolved in the first and second solvents to prepare first and second solutions having a certain concentration. The first and second solvents may each independently be at least one selected from the group consisting of chloroethane, dichloroethane, chlorobenzene, dichlorobenzene, and trichlorobenzene. The first and second solvents may be homogeneous as a mixture or a single solvent, respectively, and may be heterogeneous as necessary. For example, the first solvent may be a 1: 1 mixture of 1,2-dichloroethane and chlorobenzene, and the second solvent may be 1,2-dichlorobenzene, but the present invention is not limited thereto. Also, the concentration of the first and second solutions may be 1 to 10 wt% and 5 to 20 mg / mL, respectively, but is not limited thereto.

In the step (b), the first solution may be coated on a substrate having a gate electrode to form a gate insulating layer. Considering the productivity of the organic thin film transistor, the coating can be performed by spin coating. Also, since the first solution contains a large amount of solvent, it may be evaporated and removed by drying for a predetermined time at a predetermined temperature after the coating is completed.

In the step (c), LPUV may be irradiated to the gate insulating layer to vertically align the cinnamate-based polymer to the LPUV. At this time, the intensity of the LPUV is 5 to 50J / cm ^2, preferably can be from 10 to 30J / cm ^2. If the intensity of the LUPV is less than 5 J / cm ^2, the photo-alignment of the cinnamate-based polymer can not be sufficiently induced. If the intensity of the LUPV exceeds 50 J / cm ^2, the cinnamate-based polymer may be ununiformly photo- .

The active layer may be formed by coating the second solution on the photo-aligned gate insulating layer in the step (d). As in the step (b), the coating may be performed by spin coating to improve the productivity of the organic thin film transistor. In addition, since the second solution contains a large amount of solvent, it may be dried for a predetermined time at a predetermined temperature after evaporating and removing the coating. The drying conditions in steps (b) and (d) may be set to the same or different depending on the concentrations of the first and second solutions and the types of the solvents contained in the first and second solutions.

In the step (e), the active layer may be annealed at 100 to 300 ° C, preferably 150 to 250 ° C, to further enhance the vertical optical orientation of the thiophene-based polymer constituting the active layer to the LPUV. If the annealing temperature is less than 100 ° C., the dichroic ratio (A _⊥ / A _// ) of the thiophene polymer can not be controlled within the range of 1.2 to 1.5. If the annealing temperature is higher than 300 ° C., The structure of the organic thin film transistor may become unstable due to thermal decomposition of the mate polymer.

In step (f), gold may be deposited on the active layer through a shadow mask to form a source electrode and a drain electrode. At this time, the deposition rate and time of the gold can be adjusted to 0.1 to 5 Å / s to control the thickness of the electrode to 10 to 100 nm, and the channel length, channel width, and channel direction can be diversified through the shape of the shadow mask can do.

Example

The n-type silicon bottom-gate substrate was sequentially cleaned with acetone, ethanol, and deionized water for 10 minutes. Polyvinyl cinnamate (hereinafter referred to as 'PVCN') having a weight average molecular weight of 230,000 was dissolved in a solvent in which 1,2-dichloroethane and chlorobenzene were mixed at a ratio of 1: 1 to prepare a 5% by weight PVCN solution. The PVCN solution was spin-coated on the substrate to a thickness of 400 nm at 3,000 rpm for 60 seconds and then dried at 80 ° C for 1 hour to remove residual solvent.

The optical orientation of PVCN was induced by irradiating UVN from a 1.1 kW medium pressure mercury UV lamp onto a PVCN film at a linear intensity of 15 J / cm ² using a Glan-Taylor polarizer using a Glan-Taylor polarizer. (Hereinafter abbreviated as 'PBTTT') was dissolved in 1,2-dichlorobenzene to prepare a solution of 10 mg / mL of poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [ , Which was spin-coated on photo-oriented PVCN film at 2,000 rpm for 60 seconds and then dried at 110 ° C for 30 minutes. Thereafter, the uniaxial alignment of PBTTT was induced by annealing in an argon gas atmosphere at 180 ° C for 30 minutes.

Gold was deposited on the monoaxially oriented PBTTT film through a shadow mask at a rate of 1 A / s to form source and drain electrodes of 50 nm thickness (channel length: 20 to 100 탆, channel width: 0.5 to 1 mm, channel direction: LPUV , Thereby completing the liquid crystalline organic thin film transistor.

Comparative Example  One

A liquid crystalline organic thin film transistor was completed in the same manner as in the above example except that the PBTTT film was not annealed.

Comparative Example  2

A liquid crystalline organic thin film transistor was completed in the same manner as in the above example, except that UVN was irradiated on the PVCN film without polarizing.

Comparative Example  3

Liquid crystal organic thin film transistors were completed in the same manner as in the above example except that source and drain electrodes were formed so that the channel direction was parallel to the LPUV.

Experimental Example  One: PBTTT  Evaluation of orientation property

UV / Vis spectra were obtained for each of the PBTTT films of Examples and Comparative Example 1 using a UV / Vis / NIR spectrometer (Jasco V-570). Figure 5 shows the UV / Vis spectra of poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2-b] thiophene) according to one embodiment of the invention and comparative example .

Referring to FIG. 5, absorption bands appear in a wavelength range of 400 nm to 630 nm due to? -Π transfer of PBTTT, and all have dichroism irrespective of annealing. In particular, Referring to FIG. 5 (b), the first embodiment of the PBTTT film is shown as having a dichroic ratio _{(dichroic ratio, A ⊥ / A} //) of 1.36 at 530nm, compared to Comparative Example 1, the vertically aligned PBTTT Was relatively dominant. Through this, it can be seen that the vertically oriented PVCN for the LPUV induced the vertical orientation of the PBTTT coated thereon, and the annealing process performed under the constant temperature condition enhanced the vertical orientation of the PBTTT.

Experimental Example  2: Organic thin film  Evaluation of transistor performance

The anisotropic transfer characteristics of the organic thin film transistors of Examples and Comparative Examples 2 and 3 were measured. The results are shown in FIG. 6 and Table 2 below.

division Mobility (cm ² · V ^-1 · s ^-1 ) I _on / I _off V _th (V) Example 0.025 2.1E + 03 2.90 Comparative Example 2 0.013 1.8E + 03 -0.18 Comparative Example 3 0.008 1.6E + 03 2.79

Referring to FIGS. 6 (b) and 6 (c), the field effect mobility, the on / off current ratio I _on / I _off , and the threshold voltage , V _th ) of 0.008 cm ² / Vs, 1.6 * 10 ³ and 2.79 V, respectively, while in the case of the embodiment, 0.025 cm ² / Vs, 2.1 * 10 ³ and 2.90 V, respectively, The efficiency was relatively good.

The values shown in Table 2 indicate average values obtained by measuring the anisotropic transfer characteristics of the organic thin film transistors manufactured in the above example and comparative examples 2 and 3 by the same method for each of the 36 organic thin film transistors. Bihaeseodo to Referring to Table 2, the embodiment as a field effect mobility is 0.025cm ² / Vs, in Comparative Example 3 of 0.013cm ² / Vs of 0.008cm Comparative Example 2, about 3 times higher than the ² / Vs about 2 times higher. It is analyzed that the charge transfer in the direction perpendicular to the alignment direction of the main chain of PBTTT is enhanced, while the charge transfer in the parallel direction is suppressed.

Thus, the optically oriented PVCN film can improve the orientation of the PBTTT molecules located thereon. Unlike the rubbed polyimide surface with scratches that are unsuitable for dielectric surfaces, the optically oriented PVCN film can also function as a gate insulating layer as well as a function of the surface orientation layer. Further, the electrical performance of the organic thin film transistor can be further improved by adjusting and optimizing the optical alignment, coating, and annealing conditions during the manufacture of the liquid crystal organic thin film transistor.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (12)

A liquid crystal organic thin film transistor comprising a substrate, a gate electrode, a gate insulating layer, an active layer, and an electrode material layer sequentially,
The active layer is formed only on the gate insulating layer,
The electrode material layer and the gate insulating layer are spaced apart from each other by the active layer,
Wherein the gate insulating layer comprises a cinnamate-based polymer vertically photo-aligned with respect to linearly polarized UV,
Wherein the active layer comprises a thiophene polymer vertically oriented with respect to the linearly polarized UV,
Wherein the active layer has a dichloric ratio of 1.2 to 1.5,
The thiophene-based polymer is uniaxial aligned in the active layer,
Wherein the electrode material layer includes a source electrode and a drain electrode,
And a channel direction between the source electrode and the drain electrode is perpendicular to the linearly polarized UV. The method according to claim 1,
Wherein the thiophene-based polymer is represented by the following Formula 1:
≪ Formula 1 >

In this formula,
R ₁ and R ₂ are, independently of one another, a Cl to C20 alkyl group,
X is

,

, And

, ≪ / RTI >
and n is an integer of 1 to 10,000. 3. The method of claim 2,
Wherein the thiophene-based polymer is poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2-b] thiophene). The method according to claim 1,
Wherein the cinnamate-based polymer is at least one selected from the group consisting of polyvinylcinnamate, polyvinylmethoxycinnamate, polyvinylfluorinated cinnamate, and polysiloxane cinnamate. 5. The method of claim 4,
Wherein the cinnamate-based polymer is polyvinyl cinnamate. 6. The method of claim 5,
Wherein the polyvinyl cinnamate has a weight average molecular weight (Mw) of 50,000 to 500,000. (a) dissolving cinnamate- and thiophene-based polymers in a first solvent and a second solvent, respectively, to prepare first and second solutions;
(b) coating the first solution on a substrate provided with a gate electrode to form a gate insulating layer;
(c) vertically aligning the cinnamate-based polymer to the UV by irradiating the gate insulating layer with linearly polarized UV light;
(d) coating the second solution on the photo-aligned gate insulating layer to form an active layer;
(e) annealing the active layer at 100 to 300 캜 to adjust the dichloric ratio of the active layer to 1.2 to 1.5 and uniaxial alignment of the thiophene polymer; And
(f) depositing gold on the active layer to form a source electrode and a drain electrode,
Wherein the thiophene-based polymer in the active layer is vertically oriented with respect to the UV,
The active layer is formed only on the gate insulating layer,
The source electrode and the drain electrode are spaced apart from each other by the active layer,
And a channel direction between the source electrode and the drain electrode is perpendicular to the linearly polarized UV. 8. The method of claim 7,
Wherein the thiophene-based polymer is represented by the following Formula 1:
≪ Formula 1 >

In this formula,
R ₁ and R ₂ are, independently of one another, a Cl to C20 alkyl group,
X is

,

, And

, ≪ / RTI >
And N is an integer of 1 to 10,000. 9. The method of claim 8,
Wherein the thiophene-based polymer is poly (2,5-bis (3-dodecylthiophen-2-yl) thieno [3,2-b] thiophene). 8. The method of claim 7,
Wherein the first and second solvents are independently at least one selected from the group consisting of chloroethane, dichloroethane, chlorobenzene, dichlorobenzene, and trichlorobenzene. 8. The method of claim 7,
Wherein the coating is performed by spin coating in the steps (b) and (d). 8. The method of claim 7,
And the intensity of the linearly polarized UV in step (c) is 5 to 50 J / cm ² .

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