KR20180113396A - Vertically and laterally phase-separated semiconducting polymer/insulating polymer blend film and organic field-effect transistor comprising the same - Google Patents

Abstract

The present invention relates to a thin film for an organic thin film transistor active layer which includes an organic semiconductor material made of a diketopyrrolopyrrole (DPP) based polymer, and an insulating polymer, and has a structure in which the organic semiconductor material and the insulating polymer are vertically and horizontally phase-separated; and an organic thin film transistor including the same. When the organic thin film transistor is manufactured in the form of top contact by using the thin film for an organic thin film transistor active layer of the present invention, effective charge injection is performed through an organic semiconductor rod made of the DPP based polymer present in the upper part of the horizontally phase-separated thin film, and smooth charge transfer is possible by an organic semiconductor thin film vertically phase-separated at the lower part of the thin film. Therefore, device performance can be remarkably improved when applied to an active layer of the organic thin film transistor. In addition, the insulating polymer included in the thin film for an organic thin film transistor active layer of the present invention protects the organic semiconductor material, thereby preventing moisture/oxygen from penetrating into an organic semiconductor. Therefore, the lifetime of the organic thin film transistor can be greatly improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a semiconductor polymer / insulating polymer blend thin film, a vertical and horizontal phase-separated semiconductor polymer thin film, and an organic thin film transistor including the same. BACKGROUND ART [0002]

The present invention relates to a semiconductor polymer / insulating polymer blend thin film, and more particularly, to a semiconductor polymer / insulating polymer blend thin film for an active layer of an organic thin film transistor having a phase-separated structure.

A thin film transistor (TFT) is used as a driving element for controlling the operation of each pixel in various display devices, and is expected to be used as a smart card or a plastic chip for an inventory tag have.

Conventionally, an inorganic semiconductor material such as silicon (Si) has been generally used as a channel layer of a thin film transistor. However, since an inorganic material requiring a high-priced, high-temperature vacuum process due to large- And organic thin film transistors (OTFTs) using an organic thin film as a semiconductor layer have recently been actively studied.

The organic thin film transistor uses an organic thin film instead of a silicon film as a semiconductor layer. The organic thin film transistor includes a low-molecular organic thin film transistor using a semiconductor low-molecular material such as oligothiophene or pentacene, A polymer organic thin film transistor using a semiconductor high molecular material such as a polythiophene series and the like can be classified into a polymer organic thin film transistor having an electrical performance of an organic semiconductor obtained by thermal evaporation of a low molecular material such as pentacene, Far ahead.

However, the price of semiconducting polymers is generally high because they are synthesized in many stages under stringent conditions. Thus, the semiconductor polymer / insulating polymer blend may be a way to reduce the cost of the material, but since the charge transport is interrupted by the insulating element, the vertical The vertical phase-separation must be induced. However, since vertical phase separation can occur under well controlled conditions such as solubility, surface energy, and substrate wettability, lateral phase separation due to marangoni-instability is much more common in polymer blends .

Korean Patent Publication No. 10-2010-0070652 (published on June 28, 2010) Korean Registered Patent No. 10-1451301 (Registered on Apr. 14, 2014) Korean Patent Laid-Open No. 10-2012-0100591 (published on September 12, 2012) Korean Patent Publication No. 10-2008-0025223 (published on Mar. 20, 2008) Korean Patent Publication No. 10-2006-0070353 (published on June 23, 2006)

 Y. J. Kwon, Y. D. Park and W. H. Lee, Materials, 2016, 9, 650  W. H. Lee and Y. D. Park, Polymers, 2014, 6, 1057-1073.  S. Goffri, C. Muller, N. Stingelin-Stutzmann, D. W. Breiby, C. P. Radano, J. W. Andreasen, R. Thompson, R. A. Janssen, M. M. Nielsen, P. Smith and H. Sirringhaus, Nat. Mater., 2006, 5, 950-956.  S. G. Lee, H. S. Lee, S. Lee, C. W. Kim and W. H. Lee, Org. Electron., 2015, 24, 113-119.  H. M. Kim, H. W. Kang, D. K. Hwang, H. S. Lim, B. K. Ju and J. A. Lim, Adv. Funct. Mater., 2016, 26, 2706-2714.  D. Kwak, H. H. Choi, B. Kang, D. H. Kim, W. H. Lee and K. Cho, Adv. Funct. Mater., 2016, 26, 3003-3011.  G. H. Lu, J. Blakesley, S. Himmelberger, P. Pingel, J. Frisch, I. Lieberwirth, I. Salzmann, M. Oehzelt, R. Di Pietro, A. Salleo, N. Koch and D. Neher, Nat. Commun., 2013, 4, 1588

Disclosure of the Invention In order to solve the problems of the prior art described above, it is an object of the present invention to provide an organic / insulating polymer blend thin film for an organic thin film transistor active layer and an organic thin film including the same, The purpose of the transistor is to provide.

In order to achieve the above object, the present invention provides an organic semiconductor material comprising a diketopyrrolopyrrole (DPP) based polymer and an insulating polymer, wherein the organic semiconductor material and the insulating polymer are aligned vertically and horizontally And a phase separation of the organic thin film transistor.

A lower layer made of the organic semiconductor material; And an upper layer having a structure in which the organic semiconductor material and the insulating polymer are phase-separated in a horizontal direction. The present invention also provides a thin film for an active layer of an organic thin film transistor.

Also, the organic semiconductor material included in the upper layer has a rod shape. The present invention also provides a thin film for an active layer of an organic thin film transistor.

Also, the diketopyrrolopyrrole (DPP) -based organic semiconductor material is a polymer (29-DPP-TVT) represented by the following chemical formula:

[Chemical Formula]

.

.

The insulating polymer may include at least one selected from the group consisting of a polyacrylate-based polymer, a polystyrene (PS) -based polymer, and a polyethylene (PE) -based polymer. A thin film for an active layer of a thin film transistor is proposed.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: (a) preparing a mixed solution comprising an organic semiconductor material comprising a diketopyrrolopyrrole (DPP) based polymer and an insulating polymer; (b) applying the mixed solution on a substrate to form a coating layer; And (c) drying the coating layer. The present invention also provides a method for producing the thin film for the active layer of the organic thin film transistor.

Also, the mixed solution contains at least one selected from the group consisting of chlorobenzene, toluene, chloroform and dichloroethane as a solvent, and proposes a method for producing the thin film for an active layer of an organic thin film transistor.

In addition, the mixed solution includes an organic semiconductor material and an insulating polymer in a mass ratio of 1: 2 to 1: 5.

Further, the present invention proposes a method for manufacturing an organic thin film transistor active layer thin film, wherein the substrate is a hydrophobic treated SiO ₂ substrate.

According to another aspect of the present invention, there is provided an organic thin film transistor including the thin film for the active layer of the organic thin film transistor.

When an organic thin film transistor is manufactured in the form of top contact using the thin film for an active layer of an organic thin film transistor according to the present invention, an organic semiconductor made of a diketopyrrolopyrrole (DPP) based polymer present in an upper part of the horizontally phase- Charge injection is effectively performed through a rod, and the organic semiconductor thin film having vertical phase-separation at the bottom of the thin film can smoothly move the charge. Therefore, the device performance can be remarkably improved when applied to the active layer of the organic thin film transistor.

In addition, the insulating polymer included in the thin film for the active layer of the organic thin film transistor according to the present invention protects the organic semiconductor material, thereby preventing moisture / oxygen from penetrating into the organic semiconductor, thereby greatly improving the lifetime of the organic thin film transistor. have.

When the crystallinity of the organic semiconductor material made of the DPP polymer contained in the thin film for the organic thin film transistor according to the present invention is different, the size of the organic semiconductor rod formed by phase separation is changed. Particularly, It is possible to improve the device performance when applied to the active layer of the organic thin film transistor as the phase separation scale becomes smaller.

1 (a) is a chemical structural formula of 24-DPP-TVT, 29-DPP-TVT and PMMA, FIG. 2 is a schematic view showing a process of forming a thin film by the method of FIG.
Figures 2 (a) -2 (d) show TVT / PMMA blend films; 29-DPP-TVT / PMMA blend film; Acetic acid etched 24-DPP-TVT / PMMA blend film; (Left) and image (right) images for the acetic acid etched 29-DPP-TVT / PMMA blend film (the sketch in the height image shows the 3D profile and the sketch in the top image shows the schematic of the obtained structure Lt; / RTI >
3 (a) and 3 (c) are 2D-GIXRD patterns of 24-DPP-TVT and 29-DPP-TVT films, respectively.
Figures 4 (a) and 4 (b) are AFM height images (left) and image (right) for P3HT: PMMA (1: 3) blend film and acetic acid etched P3HT: PMMA .
Figures 5 (a) and 5 (b) are AFM height images (left) and image (right) images of 24-DPP-TVT film and 29-DPP-TVT film, respectively.
Figures 6 (a) and 6 (b) illustrate the results for a 24-DPP-TVT film, a 24-DPP- TVT / PMMA blend film, a 29- DPP- TVT film, and a 29- DPP- TVT / PMMA blend film- -I _D vs. V _G characteristics of the graph shown, and (-I _D) are graphs showing the characteristics ^1/2 versus V _G (V _D is fixed to -80V), Figure 6 (c) and 6 (d) are each 24 -DPP-TVT / PMMA blend film and the 29-DPP-TVT / PMMA blend film.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Embodiments in accordance with the concepts of the present invention can make various changes and have various forms, so that specific embodiments are illustrated in the drawings and described in detail in this specification or application. It should be understood, however, that the embodiments according to the concepts of the present invention are not intended to be limited to any particular mode of disclosure, but rather all variations, equivalents, and alternatives falling within the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms " comprises ", or " having ", or the like, specify that there is a stated feature, number, step, operation, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Hereinafter, the present invention will be described in detail with reference to examples.

The embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the embodiments described below. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art.

<Examples>

In this example, poly [2,5-bis (2-decyltetradecyl) pyrrolo [3,4-c] pyrrole-1,4- (2H, 5H) 2,5-bis (2-decyltetradecyl) pyrrolo [3,4-c] pyrrole- (2H, 5H) -dione- (E) -1,2-di (2,20-bithiophen-5-yl) ethene]), 24- DPP-TVT (Mn = 31,900, Mw = 54,230, PDI = 1.7) and 29-DPP-TVT (Mn = 33369, Mw = 60781, PDI = 1.82) were used as DPP-based semiconductor polymers (see FIG. 24-DPP-TVT and 29-DPP-TVT were synthesized.

The synthesized polymer was purified by soxhlet extraction and the final polymer (24-DPP-TVT and 29-DPP-TVT) was obtained by precipitation of a chloroform solution containing methanol as a solvent.

DPP-TVT (or 29-DPP-TVT) solution (total concentration: 8 mg / mL) containing chlorobenzene as a solvent and 24-DPP-TVT (Total concentration: 8 mg / mL) containing 1: 3 by weight of methyl methacrylate (PMMA) (Mw = 996 kg mol ^-1 ) was treated with octadecyltrichlorosilane (ODTS) Spin-cast on one SiO ₂ (thickness 300 nm) / Si substrate. DPP-TVT (or 29-DPP-TVT) film and 24-DPP-TVT (or 29-DPP-TVT) / PMMA blend film were placed in a vacuum oven to remove the excess solvent completely. An Au source / drain electrode was thermally deposited. The channel length and width of fabricated FET were 150μm and 1500μm, respectively. The atomic force microscope (AFM) was used to analyze the surface morphology of the films. The blend film was treated with acetic acid overnight to selectively etch the PMMA layer on the top surface. Two-dimensional grazing-incidence X-ray diffraction (2D-GIXRD) patterns were obtained at the Pohang Accelerator Laboratory (9A and 3C beamline) to analyze the molecular orientation of the thin film. Electrical characteristics of fabricated FETs were characterized using a Keithley 4200-SCS Source Measure Unit.

FIG. 1 (b) is a schematic view illustrating a process of forming a 24-DPP-TVT / PMMA blend film or a 29-DPP-TVT / PMMA blend film formed by spin casting.

1 (b), a 24-DPP-TVT (or 29-DPP-TVT) (1): PMMA (3) blend solution dissolved in chlorobenzene was spin cast on an SiO ₂ / Si substrate treated with ODTS 24-DPP-TVT (or 29-DPP-TVT) with low solubility is first solidified. In addition, SiO ₂ / Si substrates treated with hydrophobic ODTS inhibit the formation of a hydrophilic PMMA layer underneath. Therefore, the upper part in the solvent evaporation process is composed of a PMMA-rich phase and the lower part is a wetting layer (24-DPP-TVT) rich in 24-DPP-TVT wetting layer structure is temporarily formed. However, the vertically phase-separated transient wetting layer is unstable due to Marangoni-instrability. Thus, a transversely separated structure is formed by a concentration gradient-induced flow through the wetting layer, as schematically shown in the lower view of Figure 1 (b).

<Experimental Example>

The phase separation structure of the 24-DPP-TVT / PMMA and the 29-DPP-TVT / PMMA blending film was analyzed by analyzing the surface morphology in the AFM image (see FIGS. 2 (a) and 2 (b)). Both images showed a rugged and irregular structure. Interestingly, isolated holes were regularly observed in the 24-DPP-TVT / PMMA blend film and the 29-DPP-TVT / PMMA blend film, Respectively.

PMMA was selectively etched using acetic acid which did not dissolve 24-DPP-TVT or 29-DPP-TVT to reveal the phase separation structure of the semiconductor polymer. 2 (c) and 2 (d) show the phase separation structure of the 24-DPP-TVT and 29-DPP-TVT components in the blend film, respectively. A hairy rod consisting of a semiconductor polymer was observed in both height images, but a fewer but larger semiconductor bars were observed in the etched 24-DPP-TVT / PMMA film . In particular, the 24-DPP-TVT rod had a diameter of 1 μm, while the 29-DPP-TVT rod had a diameter of 20 nm. The formation of such semiconductor rods of different sizes is related to the crystalline behavior of 24-DPP-TVT or 29-DPP-TVT, as described below. In the height image (left column) and the 3D profile (interpolation), the rugged structure including the island model bar was found, but the contrast between the images in the right image was small, self-stratification means that an extremely thin DPP polymer layer is formed at the film-substrate interface. The phase contrast image is determined by the hardness of the material and the uniform phase image reflects the formation of a uniform DPP polymer layer on the bottom (see schematic diagram of the illustration in FIG. 2). When the thickness of the remaining DPP polymer was measured by scraping the DPP polymer with a knife, it was confirmed that an ultra-thin DPP polymer layer having a thickness of 6 to 7 nm completely covered the ODTS modified SiO ₂ / Si substrate, and the rugged rod The thickness was measured to be about 30 nm. Therefore, it was confirmed that a layer structure including an ultra thin film (lower part) and an island model rod (upper part) of a DPP type semiconductor polymer was formed on the substrate by a combination of magnetic layering and marangoni instability during the phase separation of the polymer blend.

Figures 3 (a) and 3 (c) show 2D-GIXRD patterns of 24-DPP-TVT and 29-DPP-TVT films, respectively.

Along the out-of-plane direction, (001) diffraction peaks were observed prominently in both patterns. This diffraction pattern corresponds to an edge-on layered crystal structure in which long alkyl chains are aligned perpendicular to the substrate surface. The 2D-GIXRD pattern of 29-DPP-TVT showed stronger diffraction peaks, and the angular spread of these peaks was much narrower than the diffusions of 24-DPP-TVT. Long alkyl chain spacers increase alkyl chain interactions and promote lamellar stacking. Figures 3 (b) and 3 (d) show 2D-GIXRD patterns of 24-DPP-TVT / PMMA and 29-DPP-TVT / PMMA blend films, respectively. Since the 24-DPP-TVT or 29-DPP-TVT was added as a minor component, the intensity of the (001) diffraction peak was reduced. However, the crystal structure of 24-DPP-TVT or 29-DPP-TVT did not change. In particular, a wide amorphous halo representing PMMA was seen in both blend films. The angular spread of the (001) diffraction peak of 29-DPP-TVT / PMMA is much narrower than the angular spread in 24-DPP-TVT / PMMA due to the high crystallinity of 29-DPP-TVT with long alkyl chain spacers.

When a concentration gradient-induced flow is applied to a transient wetting layer, the bottom 24-DPP-TVT or 29-DPP-TVT layer moves vertically to the surface. At this time, it is assumed that the high crystallization rate of 29-DPP-TVT in the 29-DPP-TVT / PMMA blend accelerates the evaporation of the solvent to prevent the coarsening of the 29-DPP-TVT rod. Thus, spin-cast 29-DPP-TVT / PMMA blend films contain a large number of narrow 29-DPP-TVT bars. On the other hand, the 24-DPP-TVT phase in the 24-DPP-TVT / PMMA blend is coarse during solvent evaporation to form large domains that are phase separated. This is a typical phenomenon when the crystallinity of both polymers in a polymer / polymer blend is low.

For reference, Figure 4 is an image showing a P3HT: PMMA (1: 3) blend film spin cast from chlorobenzene. Referring to FIG. 4, the AFM images before and after etching the PMMA phase exhibit a transversely phase-separated structure and include a P3HT rod having a dimension of 1 to 2 占 퐉. These island model rod structures probably originated from the phase separation characteristics of polymer blends.

On the other hand, when a homo 24-DPP-TVT or a 29-DPP-TVT is spin cast onto a substrate, the surface shape shows an uncharacteristic image without island model bars (see FIG. 5).

In order to measure the electrical characteristics of the FET using a 24-DPP-TVT film, a 29-DPP-TVT film, a 24-DPP-TVT / PMMA blend film, and a 29- DPP- TVT / PMMA blend film, .

Figures 6 (a) and 6 (b) illustrate the results for a 24-DPP-TVT film, a 24-DPP- TVT / PMMA blend film, a 29- DPP- TVT film, and a 29- DPP- TVT / PMMA blend film- -I _D vs. V _G characteristic of the device, showing transfer characteristics of the device. The field effect mobility and on / off current ratio were extracted from the transfer characteristics and are shown in Table 1 below. Due to the increased π-π interaction in longer alkyl chain spacers, the field effect mobility (0.83 cm ² V ^-1 s ^-1 ) of the 29-DPP-TVT FET is higher than that of the 24-DPP-TVT FET (0.4 cm ² V ^-1 s ^-1 ), which is in good agreement with previously reported studies. When 24-DPP-TVT or 29-DPP-TVT were mixed with PMMA, the difference in electrical properties was greatly increased (24-DPP-TVT / PMMA vs. 29-DPP-TVT / PMMA). The field effect mobility of the FET using the 24-DPP-TVT / PMMA blend was calculated to be 0.012 cm ² V ^-1 s ^-1 and lower than that of the 24-DPP-TVT FET by one order. On the other hand, the 29-DPP-TVT / PMMA blend FET has an average field-effect mobility of 0.67 cm ² V ^-1 s ^-1 and an on / off current ratio of 10 ⁸ , which is similar to that obtained from a 29-DPP-TVT FET . All devices exhibited similar downward kink behavior (see FIG. 6 (b)). A downward kink phenomenon, i.e., a decrease in saturation current at high gate voltages, has been generally observed in recently developed semiconductor polymers including electron deficient DPP units. A recent study by McCulloch et al. Discussed the origin of the downward Kink phenomenon. It is misleading to extract the field effect mobility by preventing the local electron trapping near the contact from using a gradual-channel approximation. We also calculated the field effect mobility at high gate voltages, and the extracted mobility values are summarized in Table 1 below. The mobility values extracted from the high gate voltage are much lower than those obtained at the gate voltage near the turn-on time, but are similar in that trend. For this reason, the field effect mobility can be compared and analyzed in spite of the inaccuracy of the mobility measurement.

Electrical properties of 24-DPP-TVT (or 29-DPP-TVT) film or OFET based on 24-DPP-TVT (or 29-DPP-TVT) / PMMA blend film μ ^a)
[cm ² V ^-1 s ^-1 ] μ ^b)
[cm ² V ^-1 s ^-1 ] I _ON / I _OFF DPP-C24 0.4 () 0.09 0.013 () 0.001 10 ⁷ DPP-C24 / PMMA 0.012 () 0.003 0.0008 () 0.0001 10 ⁶ DPP-C29 0.83 () 0.15 0.014 () 0.001 10 ⁸ DPP-C29 / PMMA 0.67 () 0.1 0.011 () 0.001 10 ⁸

^{a) a} value obtained at a low gate voltage near the turn-on region, ^{b) a} value obtained at a high gate voltage of Fig. 6 (b)

The difference in electrical properties is related to both the molecular orientation of the phase-separated structure of the DPP-based semiconductor polymer. The 24-DPP-TVT phase in the 24-DPP-TVT / PMMA blend exhibits a larger angular spread in the molecular orientation, thus exhibiting a lower field effect mobility, - It contrasts significantly with the DPP-TVT image. In addition, the 29-DPP-TVT bar of the 29-DPP-TVT / PMMA blend provides an efficient site for charge injection, while a smaller number of 24-DPP- (Fig. 6 (c) and 6 (d)). Since the thin 24-DPP-TVT layer with a thickness of 6 to 7 nm completely covers the SiO ₂ / Si substrate modified with ODTS, adverse effects due to lateral phase separation in the channel region can be minimized. Interestingly, DPP-based semiconducting polymer / PMMA FETs have lower turn-on voltities than homo DPP-based semiconducting polymer FETs because the DPP-based semiconductor polymers are partially passivated by PMMA . Since the FET fabrication process is performed under atmospheric conditions, oxygen and water molecules penetrate into the channel region and accumulate hole carriers (a positive shift of the turn-on voltage). In the DPP-based semiconductor polymer / PMMA blend film, since the PMMA partially passivates the DPP-based semiconductor polymer, the above effect can be reduced.

As described in detail above, in the embodiment according to the present invention, the phase separation and electrical characteristics of the semiconductor polymer / poly (methyl methacrylate) (PMMA) blend based on diketopyrrolopyrrole (DPP) In order to compare the effects of crystalline nature, DPP-based semiconductor polymers having alkyl chain spacers (C24 and C29) of different lengths were used.

Due to self-stratification and marangoni-instability in the phase separation process of the polymer blend, a hierarchical structure including an ultra-thin film (lower part) made of a DPP-based semiconductive polymer and an island model rod (upper part) Lt; / RTI &gt; In particular, the 24-DPP-TVT / PMMA blend film formed a smaller number of semiconductor rods while the size was larger due to coarsening on 24-DPP-TVT during solvent evaporation. On the other hand, the high crystallinity of 29-DPP-TVT prevented the coarsening of the 29-DPP-TVT rod to form a densely packed semiconductor rod.

According to the crystallinity of the DPP-based semiconductor polymer, the 29-DPP-TVT phase in the 29-DPP-TVT / PMMA blend has a lower angular spread in the molecular orientation than in the 24-DPP- angular spread). Therefore, the 29-DPP-TVT / PMMA field effect transistor (FET) showed much higher electrical characteristics than the 24-DPP-TVT / PMMA FET. In addition, the field-effect mobility is similar to the field effect of a homo 29-DPP-TVT FET, but the partial passivation effect in a 29-DPP-TVT / / PMMA FET turn-on voltage.

In other words, the molecular orientation of the DPP polymer and the phase separation structure of the blend film all affected the electrical properties of the DPP-based polymer / PMMA blend-based FET and the more observed in the FETs of the 29-DPP-TVT / PMMA blend The high field effect mobility showed a strong dependence of the crystallinity of the semiconductor polymer used in the polymer blend in the OFET.

As noted above, the present invention provides guidance in selecting suitable semiconductor polymers that can improve the electrical properties of OFETs based on dual (vertical / horizontal) phase separation of semiconductor / insulating polymer blends , Another meaning of the present invention can be found.

Claims (10)

An organic semiconductor material comprising a diketopyrrolopyrrole (DPP) based polymer, and an insulating polymer,
Wherein the organic semiconductor material and the insulating polymer are phase separated in a vertical direction and a horizontal direction. The method according to claim 1,
A lower layer made of the organic semiconductor material; And an upper layer having a structure in which the organic semiconductor material and the insulating polymer are phase-separated in a horizontal direction. 3. The method of claim 2,
Wherein the organic semiconductor material included in the upper layer has a rod shape. The method according to claim 1,
Wherein the diketopyrrolopyrrole (DPP) organic semiconductor material is a polymer (29-DPP-TVT) represented by the following formula:
[Chemical Formula]

.
The method according to claim 1,
Wherein the insulating polymer comprises at least one selected from the group consisting of a polyacrylate-based polymer, a polystyrene (PS) -based polymer, and a polyethylene (PE) -based polymer. Thin film for active layer. (a) preparing a mixed solution comprising an organic semiconductor material comprising a diketopyrrolopyrrole (DPP) based polymer and an insulating polymer;
(b) applying the mixed solution on a substrate to form a coating layer; And
(c) drying the coating layer.
A method for producing an organic thin film transistor active layer thin film according to any one of claims 1 to 5. The method according to claim 6,
Wherein the mixed solution contains at least one selected from the group consisting of chlorobenzene, toluene, chloroform, and dichloroethane as a solvent. The method according to claim 6,
Wherein the mixed solution comprises an organic semiconductor material and an insulating polymer in a mass ratio of 1: 2 to 1: 5. The method according to claim 6,
Wherein the substrate is a hydrophobically treated SiO ₂ substrate. An organic thin film transistor comprising the thin film according to any one of claims 1 to 5.

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