JP2015159169A - Composition for electrode modification, method for electrode modification, and organic thin film transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for electrode modification which enables the selective and efficient attachment to an electrode surface, and which enables the execution of a process for increase in electric charge transfer exclusively on an electrode surface e.g. in manufacturing an organic thin film transistor.SOLUTION: A composition for electrode modification of the present invention comprises: (A) a thiol compound of which the ionization potential is 5.0-6.1 eV; and (B) a solvent. The (B) component includes (B1) alcohol-based solvent of which the boiling point is 150-250°C. The surface tension of the composition is 30-50 mN/m.

Description

  The present invention relates to an electrode modifying composition, an electrode modifying method, and an organic thin film transistor.

In an organic thin film transistor (organic TFT) using an organic semiconductor, there is a problem that if the difference between the work function of the electrode and the ionization potential of the organic semiconductor is large, the transfer of charges does not work and the operating voltage rises.
In order to solve such a problem, a technique for treating an electrode surface with a compound having an ionization potential close to that of an organic semiconductor is known (see, for example, Patent Documents 1 to 3).

US Pat. No. 6,335,539 JP 2008-60117 A International Publication No. 2011/132425

In the techniques described in Patent Documents 1 to 3, it is preferable that the substance for treating the electrode surface exists only on the electrode surface and does not exist in other portions. In particular, if it exists in a portion between the source electrode and the drain electrode, there is a risk that the off current of the organic thin film transistor increases.
However, Patent Documents 1 to 3 disclose a method of treating the surface of an electrode of a thin film transistor with a chemical solution containing a thiol compound or conductive polyaniline, but a substance is present only on the surface of the electrode. No means are disclosed. For this reason, depending on the composition of the chemical solution, there is a problem that a process for cleaning portions other than the electrode is required after the electrode processing, and a huge chemical bath is required when processing a large substrate. That is, in the production of an organic thin film transistor, a highly productive means is required in which the surface treatment agent is selectively attached only to the surfaces of the source electrode and the drain electrode.

  Therefore, the present invention can be selectively and efficiently attached to the electrode surface. For example, in the manufacture of an organic thin film transistor, an electrode capable of performing a treatment for improving charge transfer only on the electrode surface. The object is to provide a composition for modification, an electrode modification method using the composition, and an organic thin film transistor.

In order to solve the above problems, the present invention provides the following electrode modification composition, electrode modification method, and organic thin film transistor.
The composition for electrode modification of the present invention includes (A) a thiol compound having an ionization potential of 5.0 eV or more and 6.1 eV or less, and (B) a solvent. The component (B) has a boiling point (B1). It contains an alcohol solvent at 150 ° C. or more and 250 ° C. or less, and the composition has a surface tension of 30 mN / m or more and 50 mN / m or less.
In the electrode modifying composition of the present invention, the component (B) is a single solvent or a mixed solvent composed of two or more solvents, and in the case of a mixed solvent, the most of these two or more solvents. The surface tension of the solvent having a high boiling point is preferably 35 mN / m or more and 50 mN / m or less.
In the electrode modifying composition of the present invention, the surface free energy of the electrode modified with the component (A) is preferably 25 mN / m or more and 40 mN / m or less.

In the electrode modifying composition of the present invention, the concentration of the component (A) is preferably 0.1% by mass or more and 10% by mass or less based on the total amount of the composition.
In the electrode modifying composition of the present invention, the component (A) is 4-trifluoromethylbenzenethiol, 3-trifluoromethylbenzenethiol, pentafluorobenzenethiol, 2,3,5,6-tetrafluorobenzene. Thiol, 2,3,5,6-tetrafluoro-4- (trifluoromethyl) benzenethiol, 2,3,5,6-tetrafluoro-4-mercaptobenzoic acid methyl ester, 3,5-bistrifluoromethylbenzene It is preferably at least one compound selected from the group consisting of thiol, 4-fluorobenzenethiol and 4-nitrobenzenethiol.

In the composition for electrode modification of the present invention, the blending amount of the component (B1) is preferably 50% by mass or more based on the total amount of the component (B).
In the composition for electrode modification of the present invention, the component (B1) is 1,3-propanediol, 1,2-propanediol, ethylene glycol, 3-methoxy-1,2-propanediol, 1,2- It is preferably at least one compound selected from the group consisting of butanediol, 1,3-butanediol, cyclohexanol, propyl lactate and ethyl lactate.
In the electrode modifying composition of the present invention, the component (B1) is preferably a dihydric alcohol.
In the electrode modifying composition of the present invention, the component (B) preferably further contains (B2) an alcohol solvent having a boiling point of less than 150 ° C.
In the composition for electrode modification of the present invention, the component (B2) comprises methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, pentanol and 1-methoxy-2-propanol. It is preferably at least one solvent selected from the group.

The electrode modification method of the present invention is an electrode modification method for modifying the surface of at least one of a source electrode and a drain electrode in an organic thin film transistor, using the composition for electrode modification, screen printing method, reverse offset printing. The electrode is modified by a printing method selected from a printing method, a flexographic printing method, and an inkjet printing method.
Another electrode modification method of the present invention is an electrode modification method for modifying a surface of at least one of a source electrode and a drain electrode in an organic thin film transistor, wherein the organic thin film transistor has an interval between the source electrode and the drain electrode. A step of attaching the electrode modifying composition to the electrode-attached substrate having the source electrode and the drain electrode, wherein the electrode-attached substrate comprises: The relationship among the surface free energy (SFE-S), the surface free energy of the drain electrode (SFE-D), and the surface free energy (SFE-GI) of the portion between the source electrode and the drain electrode is expressed by the following formula: It is a method characterized by satisfying at least one of (F1) and (F2).
(SFE-GI) <(SFE-S) (F1)
(SFE-GI) <(SFE-D) (F2)
In this electrode modification method, it is preferable that the electrode is modified by any one of screen printing, reverse offset printing, flexographic printing, and inkjet printing.
In the electrode modification method of the present invention, the organic thin film transistor is preferably formed by a printing method.

The organic thin film transistor of the present invention is an organic thin film transistor having a substrate, a gate electrode, a source electrode, a drain electrode, an insulator layer, and an organic semiconductor layer, wherein the source electrode and The surface of at least one of the drain electrodes is modified, and the surface free energy (SFE-S2) of the source electrode and the surface free energy of the drain electrode (SFE-D2) after the electrode modification by the electrode modification method. ) And the surface free energy (SFE-GI2) relationship of the portion between the source electrode and the drain electrode satisfies both the following formulas (F3) and (F4).
| (SFE-S2)-(SFE-GI2) | <10 mN / m (F3)
| (SFE-D2)-(SFE-GI2) | <10 mN / m (F4)

  According to the present invention, it is possible to selectively and efficiently adhere to the electrode surface. For example, in the manufacture of an organic thin film transistor, an electrode capable of performing a treatment for improving charge transfer only on the electrode surface. A composition for modification, an electrode modification method using the composition, and an organic thin film transistor can be provided.

It is the schematic which shows the board | substrate with an electrode before making the composition for electrode modification in this embodiment adhere. In this embodiment, it is the schematic which shows the state immediately after apply | coating the composition for electrode modification to the board | substrate with an electrode. In this embodiment, after apply | coating the composition for electrode modification to the board | substrate with an electrode, it is the schematic which shows the state which the composition for electrode modification flowed. In this embodiment, after apply | coating the composition for electrode modification to the board | substrate with an electrode, it is the schematic which shows the state dried and solidified. It is the schematic which shows the organic thin-film transistor obtained by this embodiment. It is the schematic which shows the other organic thin-film transistor obtained by this embodiment.

[Electrode modification composition]
First, the electrode modification composition of the present invention will be described.
The composition for electrode modification of the present invention (hereinafter also referred to as “the present composition”) includes (A) a thiol compound having an ionization potential of 5.0 eV or more and 6.1 eV or less, and (B) a solvent described below. Is included.
The surface tension of the present composition needs to be 30 mN / m or more and 50 mN / m or less. When the surface tension is less than the lower limit, the composition tends to adhere to parts other than the electrode, and the composition cannot be selectively attached to the electrode part. On the other hand, when the surface tension exceeds the upper limit, the composition is easily repelled even in the electrode portion, and the composition cannot be sufficiently adhered to the electrode portion. From the above viewpoint, the surface tension of the composition is more preferably from 35 mN / m to 45 mN / m, particularly preferably from 37 mN / m to 44 mN / m. The surface tension can be measured by a pendant drop method.
The viscosity of the present composition is preferably 0.5 mPa · s or more and 200 Pa · s or less, although a suitable viscosity range varies depending on the printing method. When the viscosity of the composition is within the above range, coating properties and fluidity after coating can be ensured. The viscosity is a viscosity measured at 25 ° C. and is generally used for a vibration type (tuning fork type) viscometer (for example, a tuning fork type viscometer SV-1A type manufactured by A & D) or a rotational viscometer. It can be measured with a typical viscometer.
In addition, as a means to adjust the surface tension and viscosity of this composition, adjusting the kind and compounding quantity of (B) component, etc. are mentioned.

((A) component)
(A) component in this composition is a thiol compound whose ionization potential is 5.0 eV or more and 6.1 eV or less. When the ionization potential of the component (A) is within the above range, the work function of the surface of the electrode can be increased when the surface of the organic thin film transistor such as the source electrode and the drain electrode is modified with the present composition. As a result, a gradient that reduces the difference between the work function of the electrode and the ionization potential of the organic semiconductor can be formed, and the charge transfer between the electrode and the organic semiconductor can be smoothly performed, so that the operating voltage of the organic thin film transistor can be reduced. . The ionization potential of the component (A) is more preferably 5.3 eV or more and 6.1 eV or less.
The surface free energy of the electrode modified with the component (A) is preferably 25 mN / m or more and 45 mN / m or less, more preferably 25 mN / m or more and 40 mN / m or less, and 28 mN / m or more and 40 mN / m or less. Even more preferably: Thereby, the difference of the surface free energy of an electrode and the part between electrodes can be made small, and the applicability | paintability of organic-semiconductor ink can be improved. The surface free energy can be calculated from the contact angles of a plurality of types of liquids whose surface tension is known.

  As component (A), 4-trifluoromethylbenzenethiol, 3-trifluoromethylbenzenethiol, pentafluorobenzenethiol, 2,3,5,6-tetrafluorobenzenethiol, 2,3,5,6-tetra Fluoro-4- (trifluoromethyl) benzenethiol, 2,3,5,6-tetrafluoro-4-mercaptobenzoic acid methyl ester, 3,5-bistrifluoromethylbenzenethiol, 4-fluorobenzenethiol, 4-nitrobenzene Examples include thiol. These may be used alone or in combination of two or more. Among these, 4-trifluoromethylbenzenethiol, 3-trifluoromethylbenzenethiol, and pentafluorobenzenethiol are preferable from the viewpoint of ionization potential and surface free energy of the modified electrode.

  The concentration of the component (A) is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 5% by mass or less, based on the total amount of the composition. It is particularly preferable that the content be 5% by mass or more and 2% by mass or less. If the blending amount of the component (A) is less than the lower limit, the surface of the electrode tends to be not sufficiently treated. On the other hand, if the amount exceeds the upper limit, surplus (A ) Components tend to be produced and productivity tends to decrease.

((B) component)
Component (B) in the present composition is a solvent. This component (B) needs to contain (B1) an alcohol solvent having a boiling point of 150 ° C. or higher and 250 ° C. or lower. If the boiling point of the component (B1) is less than the lower limit, the drying after applying the composition is too fast, and the component (A) remains in the portion other than the electrode portion, and the portion other than the electrode portion (A) The components are adsorbed and permeated, and the composition cannot be selectively attached to the electrode portion. On the other hand, when the boiling point of the component (B1) exceeds the upper limit, workability is lowered in terms of drying temperature and drying time. The boiling point of the component (B1) is more preferably 180 ° C. or higher and 220 ° C. or lower.
The component (B) is preferably a mixed solvent composed of two or more solvents. At this time, the surface tension of the solvent having the highest boiling point among these two or more solvents is preferably 35 mN / m or more and 50 mN / m or less, more preferably 37 mN / m or more and 45 mN / m or less. It is particularly preferably 40 mN / m or more and 44 mN / m or less. Thus, the component (B) may contain, in addition to the component (B1), (B2) an alcohol solvent having a boiling point of less than 150 ° C., and (B3) a solvent other than the alcohol solvent.

The component (B1) may be a monohydric alcohol, a dihydric alcohol, or a trihydric or higher polyhydric alcohol. From the viewpoint of the boiling point and the surface tension of the present composition, the component (B1) is divalent. An alcohol (diol compound) is preferred.
As the component (B1), 1,3-propanediol (boiling point: 214 ° C., surface tension: 41.1 mN / m), 1,2-propanediol (boiling point: 186 ° C., surface tension: 38.0 mN / m) , Ethylene glycol (boiling point: 196 ° C., surface tension: 43.4 mN / m), 3-methoxy-1,2-propanediol (boiling point: 220 ° C., surface tension: 39.7 mN / m), 1,2-butane Diol (boiling point: 190 ° C., surface tension: 37.2 mN / m), 1,3-butanediol (boiling point: 204 ° C., surface tension: 37.2 mN / m), cyclohexanol (boiling point: 160 ° C., surface tension: 32.5 mN / m), propyl lactate (boiling point: 174 ° C., surface tension: 33.3 mN / m), ethyl lactate (boiling point: 154 ° C., surface tension: 33.2 mN / m), and the like. These may be used alone or in combination of two or more. Among these, 1,3-propanediol, 1,2-propanediol, and ethylene glycol are preferable from the viewpoints of boiling point and surface tension.

  The blending amount of the component (B1) is preferably 50% by mass or more, and more preferably 70% by mass or more based on the total amount of the component (B).

Examples of the component (B2) include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, pentanol, and 1-methoxy-2-propanol. These may be used alone or in combination of two or more.
Examples of the component (B3) include hydrocarbon solvents, ketone solvents, ester solvents, ether solvents, and halogen solvents. These may be used alone or in combination of two or more.

The boiling point of the component (B3) is preferably 150 ° C. or higher and 240 ° C. or lower. Moreover, it is preferable that the boiling point of (B3) component is lower than the boiling point of (B1) component.

In addition to the component (A) and the component (B), additives such as an antifoaming agent and a surfactant may be added to the composition as necessary. As a compounding quantity of these additives, it is preferable that it is 1 mass% or less with respect to this composition whole quantity.
The present composition can be produced by blending the above-described components (A) and (B) at the predetermined ratio and stirring and mixing them.

[Electrode modification method]
Next, the electrode modification method of the present invention will be described with reference to the drawings. 1-5 is a figure for demonstrating the one aspect | mode of the electrode modification method of this invention. In the present embodiment, one embodiment of the electrode modification method of the present invention will be described as an example, but the electrode modification method of the present invention is not limited to this.
The electrode modification method of this embodiment is an electrode modification method for modifying the surface of at least one of the source electrode 11 and the drain electrode 12 in the organic thin film transistor 1 as shown in FIGS. And it is the method of modifying the surface of at least one of the source electrode 11 and the drain electrode 12 of the board | substrate 100 with an electrode using the composition 2 for electrode modification of this invention. Specifically, the electrode modification composition 2 is applied to the electrode-attached substrate 100 by a printing method, and the electrode modification composition 2 is dried, so that the source electrode 11 and the drain electrode 12 are And a modification step of modifying at least one surface.

As shown in FIG. 1, the electrode-equipped substrate 100 includes a gate electrode 15 and an insulator layer 14 in this order on the substrate 10, and is formed on the insulator layer 14 so as to face each other at a predetermined interval. A pair of source electrode 11 and drain electrode 12 are provided.
In the electrode modification method of this embodiment, the surface free energy (SFE-S) of the source electrode 11, the surface free energy (SFE-D) of the drain electrode 12, and the source electrode 11 and the drain electrode 12 in the substrate with electrode 100. The surface free energy (SFE-GI) relationship of the portion 14a between the two satisfies at least one of the following mathematical formulas (F1) and (F2). When such conditions are satisfied, the electrode modifying composition can be selectively attached to the electrode portion by the presence of the portion where the electrode modifying composition is easily repelled and the portion where the composition is easily adhered. Further, from the same viewpoint, it is more preferable that both the following mathematical formulas (F1) and (F2) are satisfied.
(SFE-GI) <(SFE-S) (F1)
(SFE-GI) <(SFE-D) (F2)
Note that as means for satisfying the mathematical formulas (F1) and (F2), the materials (type of metal, additive, etc.) of the source electrode 11 and the drain electrode 12 are adjusted, the insulator layer 14 and the like are used. Examples thereof include adjusting the material and treating the surface of the insulator layer 14 and the like.

In the coating step, as shown in FIG. 2, the electrode modifying composition 2 is adhered onto the electrode-attached substrate 100 by a printing method. 2 and 3 are exaggerated so that the presence of the electrode modifying composition 2 can be easily understood.
Examples of the printing method include screen printing, reverse offset printing, flexographic printing, and inkjet printing. According to these printing methods, the composition for electrode modification can be applied appropriately.
The coating amount of the electrode modifying composition 2 is not particularly limited, but is usually in the range of 1 nL / cm ^{2 to} 10 μL / cm ² .
From the viewpoint of modifying the surface of the source electrode 11, the drain electrode 12, and the like with the thiol group (—SH) of the component (A) in the electrode modifying composition 2, the materials such as the source electrode 11, the drain electrode 12, and the like. It is preferable that at least the surface contains a noble metal such as gold, silver, palladium, platinum and iridium or a metal which forms a stable sulfide such as copper, nickel, iron, tin and titanium.

In the modification step, as shown in FIGS. 3 and 4, the electrode modification composition 2 is dried to modify the surfaces of the source electrode 11 and the drain electrode 12.
In the portion 14a between the source electrode 11 and the drain electrode 12, the electrode modifying composition 2 is repelled, and the electrode modifying composition 2 gathers around the source electrode 11 and the drain electrode 12, as shown in FIG. When the electrode modifying composition 2 is dried in such a state, the modified portion 16 can be selectively formed so as to cover the source electrode 11 and the drain electrode 12 as shown in FIG. In such a case, the drying conditions are not particularly limited, but the drying temperature is usually in the range of 20 ° C. or higher and 150 ° C. or lower. The drying time is usually in the range of 10 seconds to 30 minutes.

According to the electrode modification method of this embodiment, the surface of at least one of the source electrode 11 and the drain electrode 12 in the organic thin film transistor 1 can be modified as described above.
Moreover, since the electrode modification method of this embodiment is a method which can modify an electrode by a printing method as mentioned above, it is a particularly suitable method when the organic thin-film transistor 1 is formed by a printing method. .

[Organic thin film transistor]
Next, the organic thin-film transistor of this invention is demonstrated based on drawing. FIG. 5 is a schematic view showing an organic thin film transistor obtained in the present embodiment. FIG. 6 is a schematic view showing another organic thin film transistor obtained in this embodiment.
The organic thin film transistor 1 of FIG. 5 has a gate electrode 15 and an insulator layer 14 in this order on a substrate 10, and a pair of source electrode 11 and drain formed on the insulator layer 14 at a predetermined interval. The electrode 12 is provided, the modification part 16 is formed on the surface of the source electrode 11 and the drain electrode 12, and the organic semiconductor layer 13 is formed thereon. A partial region of the organic semiconductor layer 13 forms a channel portion, and an on / off operation is performed by controlling a current flowing between the source electrode 11 and the drain electrode 12 with a voltage applied to the gate electrode 15. .
Here, the channel portion is defined as a region surrounded by a channel length (a distance between the source electrode and the drain electrode), a channel width (a width between the source electrode and the drain electrode), and a film thickness of the organic semiconductor layer.

  An organic thin film transistor 1A in FIG. 6 has a source electrode 11 and a drain electrode 12 formed on a substrate 10 so as to face each other with a predetermined gap therebetween. The modification part 16 is formed. An organic semiconductor layer 13 is formed so as to cover the source electrode 11, the drain electrode 12, and the gap between them, and an insulator layer 14 is further laminated. A gate electrode 15 is formed on the insulator layer 14 and on the gap between the source electrode 11 and the drain electrode 12.

In the organic thin film transistors 1 and 1A of the present embodiment, the modified portion 16 is formed on the surface of the source electrode 11 and the drain electrode 12 by the electrode modification method of the present invention. Therefore, the work functions of the surfaces of the source electrode 11 and the drain electrode 12 can be increased. As a result, a gradient that reduces the difference between the work function of the source electrode 11 and the drain electrode 12 and the ionization potential of the organic semiconductor layer 13 is formed, and the charge between the source electrode 11 and the drain electrode 12 and the organic semiconductor layer 13 is increased. Therefore, the operating voltage of the organic thin film transistors 1 and 1A can be reduced.
Moreover, in the organic thin-film transistors 1 and 1A of the present embodiment, the surface free energy (SFE-S2) of the source electrode and the surface free energy (SFE-D2) of the drain electrode after electrode modification by the electrode modification method of the present invention. ) And the surface free energy (SFE-GI2) relationship of the portion between the source electrode and the drain electrode satisfy both the following formulas (F3) and (F4). When such a condition is satisfied, the difference in surface free energy between the surfaces of the source electrode 11 and the drain electrode 12 and the portions 14a and 10a between the source electrode 11 and the drain electrode 12 is reduced. The applicability of can be improved.
| (SFE-S2)-(SFE-GI2) | <10 mN / m (F3)
| (SFE-D2)-(SFE-GI2) | <10 mN / m (F4)
Further, from the same viewpoint, it is more preferable that both the following mathematical formulas (F3a) and (F4a) are satisfied.
| (SFE-S2)-(SFE-GI2) | <7 mN / m (F3a)
| (SFE-D2)-(SFE-GI2) | <7 mN / m (F4a)
As means for satisfying the mathematical formulas (F3) and (F4), the component (A) in the electrode modifying composition is adjusted, and the materials such as the insulator layer 14 and the substrate 10 are adjusted. In addition, the surface of the insulator layer 14 and the substrate 10 may be treated.

  The organic thin film transistor of the present embodiment has a field effect transistor (FET) structure. As described above, there are several configurations depending on the position of the electrode, the layer stacking order, and the like. An organic thin film transistor is formed with a predetermined distance from an organic semiconductor layer (organic compound layer), a source electrode and a drain electrode formed to face each other with a predetermined distance from each other, and a source electrode and a drain electrode. And a current flowing between the source and drain electrodes is controlled by applying a voltage to the gate electrode. Here, the distance between the source electrode and the drain electrode is determined by the use of the organic thin film transistor of the present invention, and is usually 0.1 μm or more and 1 mm or less, preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably. Is 5 μm or more and 50 μm or less.

In addition to the element configuration of the organic thin film transistors 1 and 1A, various configurations of organic thin film transistors have been proposed as organic thin film transistors. It is not limited to these element configurations as long as the current flowing between the source electrode and the drain electrode is controlled by the voltage applied to the gate electrode and an effect such as on / off operation and amplification is exhibited. Absent.
For example, the top-and-bottom contact type organic thin film transistor (not shown) proposed by Yoshida et al. Of the National Institute of Advanced Industrial Science and Technology in the 49th Applied Physics-related Joint Lecture Proceedings 27a-M-3 (March 2002) Alternatively, it may have a device configuration such as a vertical organic thin film transistor (not shown) proposed by Kudo et al. Of Chiba University on the IEEJ Transactions 118-A (1998), page 1440.

In the organic thin-film transistors 1 and 1A of the present embodiment, known components can be applied to the constituent members such as the organic semiconductor layer, the substrate, the electrode, and the insulator layer.
Hereinafter, examples of constituent members of the organic thin film transistor will be described.

(Organic semiconductor layer)
The organic semiconductor layer in the organic thin film transistor of the present invention is a layer formed by using an organic semiconductor ink containing an organic semiconductor material and a solvent. The organic semiconductor layer can be formed by a dry process such as a vacuum evaporation method using an organic semiconductor material. The film thickness of the organic semiconductor layer is not particularly limited, but is usually 0.5 nm to 1 μm and preferably 2 nm to 250 nm.
When the crystallinity of the organic semiconductor layer is improved, field effect mobility is improved, and it is preferable to perform annealing after film formation because a high-performance device can be obtained. The annealing temperature is preferably 50 ° C. or more and 200 ° C. or less, more preferably 70 ° C. or more and 200 ° C. or less, and the time is preferably 10 minutes or more and 12 hours or less, more preferably 30 minutes or more and 10 hours or less, and more preferably 1 hour or more and 10 hours or less. It is still more preferable that it is less than time.
As a method for applying the organic semiconductor ink, a plate printing method such as gravure printing or offset printing, a coating method such as a casting method, a spin coating method, or an ink jet method can be employed.

  As the organic semiconductor material used in the organic semiconductor ink, known organic semiconductor materials can be used, and π-conjugated polymers are widely used. Polypyrroles, polythiophenes, polyanilines, polyallylamines, fluorenes, polycarbazoles, polyindoles And poly (P-phenylene vinylene) can be used. In addition, low-molecular substances having solubility in organic solvents, for example, polycyclic aromatic derivatives such as pentacene, phthalocyanine derivatives, perylene derivatives, tetrathiafulvalene derivatives, sulfur-containing heterocyclic compounds (for example, BTBT, TES-ADT) Etc.), oxygen-containing heterocyclic compounds, nitrogen-containing heterocyclic compounds (such as carbazole), tetracyanoquinodimethane derivatives, fullerenes, carbon nanotubes, and the like.

  As the solvent used in the organic semiconductor ink, known solvents can be used, and alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, ether solvents, halogen solvents and the like can be used. These solvents may be used alone or in a combination of two or more. The combination of these solvents can be appropriately adjusted according to the method for applying the organic semiconductor ink.

(substrate)
The substrate in the organic thin film transistor of the present invention plays a role of supporting the structure of the organic thin film transistor. As a material, in addition to glass, inorganic compounds such as metal oxides and nitrides, plastic films (PET, PES, PC) It is also possible to use metal substrates or composites or laminates thereof. Further, when the structure of the organic thin film transistor can be sufficiently supported by the components other than the substrate, it is possible not to use the substrate. In addition, a silicon (Si) wafer may be used as a material for the substrate. In this case, Si itself can be used as a gate electrode / substrate. Further, the surface of Si can be oxidized to form SiO ₂ and used as an insulating layer. In this case, a metal layer such as gold may be formed on the Si substrate serving as the substrate and gate electrode as an electrode for connecting the lead wire.

(electrode)
In the organic thin film transistor of the present invention, the material of the gate electrode, the source electrode and the drain electrode is not particularly limited as long as it is a conductive material, platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony, tantalum, Indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin oxide / antimony, indium tin oxide (ITO), fluorine doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and Carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium-potassium alloy, magnesium / copper mixture, magnesium / silver mixture Things, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, can be used as the lithium / aluminum mixture, a conductive polymer.
The material of the source electrode and drain electrode is at least gold on the surface from the viewpoint of modifying the surface of the source electrode and drain electrode with the thiol group (—SH) of the component (A) in the electrode modification composition. It is preferable to contain a noble metal such as silver, palladium, platinum or iridium, or a metal which forms a stable sulfide such as copper, nickel, iron, tin or titanium.

  Examples of the electrode forming method include means such as vapor deposition, electron beam vapor deposition, sputtering, atmospheric pressure plasma method, ion plating, chemical vapor deposition, electrodeposition, electroless plating, spin coating, printing, and ink jet. . Moreover, as a method of patterning as necessary, a method of forming a conductive thin film formed by using the above method using a known photolithography method or a lift-off method, on a metal foil such as aluminum or copper There is a method of forming and etching a resist by thermal transfer, ink jet, or the like.

  The thickness of the electrode formed in this way is not particularly limited as long as current conduction is present, but it is preferably in the range of 0.2 nm to 10 μm, more preferably 4 nm to 300 nm. Within this preferable range, the film thickness is too thin, so that the resistance increases and a voltage drop does not occur. Moreover, since it is not too thick, it does not take a long time to form a film, and when another layer such as a protective layer or an organic semiconductor layer is laminated, the laminated film can be made smoothly without causing a step.

  In the organic thin film transistor of the present invention, the source electrode, the drain electrode, and the gate electrode can be formed using a fluid electrode material such as a solution, paste, ink, or dispersion containing the above-described conductive material. In particular, a fluid electrode material containing conductive polymer or metal fine particles containing platinum, gold, silver, or copper is preferable. As the dispersion containing metal fine particles, for example, a known conductive paste or the like may be used, but it is a dispersion containing metal fine particles having a particle diameter of usually 0.5 nm to 50 nm, 1 nm to 10 nm. And preferred. Examples of the material of the metal fine particles include platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony, lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, Tungsten, zinc, or the like can be used. It is preferable to form an electrode using a dispersion in which these metal fine particles are dispersed in water or a dispersion medium which is an arbitrary organic solvent using a dispersion stabilizer mainly composed of an organic material. As a method for producing such a dispersion of metal fine particles, metal ions can be reduced in the liquid phase, such as in-gas evaporation, sputtering, and metal vapor synthesis, as well as in colloidal and coprecipitation methods. And a chemical production method for producing metal fine particles, preferably disclosed in JP-A-11-76800, JP-A-11-80647, JP-A-11-319538, JP-A-2000-239853, and the like. Colloidal methods, gas evaporation methods described in JP-A Nos. 2001-254185, 2001-53028, 2001-35255, 2000-124157, 2000-123634, etc. This is a dispersion of produced metal fine particles.

  These metal fine particle dispersions may be directly patterned by an ink jet method, or may be formed from a coating film by lithograph or laser ablation. Moreover, the patterning method by printing methods, such as a letterpress, an intaglio, a planographic printing, and screen printing, can also be used. After forming the electrode and drying the solvent, the fine metal particles are heat-fused by heating in a range of 100 ° C. to 300 ° C., preferably 150 ° C. to 200 ° C., if necessary. An electrode pattern having a desired shape can be formed.

  Furthermore, it is also preferable to use a known conductive polymer whose conductivity is improved by doping as another gate electrode, source electrode, and drain electrode material. For example, conductive polyaniline, conductive polypyrrole, conductive polythiophene ( Polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid complex, etc.) are also preferably used. These forming methods may also be patterned by an ink-jet method, or may be formed from a coating film by lithography, laser ablation, or the like. Moreover, the patterning method by printing methods, such as a letterpress, an intaglio, a planographic printing, and screen printing, can also be used.

(Insulator layer)
The material of the insulator layer in the organic thin film transistor of the present invention is not particularly limited as long as it has electrical insulation and can be formed as a thin film. Metal oxide (including silicon oxide), metal nitride ( Materials having a room temperature electrical resistivity of 10 Ωcm or higher, such as silicon nitride), polymers, and organic small molecules, can be used, and an inorganic oxide film having a high relative dielectric constant is particularly preferable.
Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Barium titanate, barium magnesium fluoride, lanthanum oxide, fluorine oxide, magnesium oxide, bismuth oxide, bismuth titanate, niobium oxide, strontium bismuth titanate, strontium bismuth tantalate, tantalum pentoxide, niobium tantalate Examples thereof include bismuth oxide, trioxide yttrium, and combinations thereof, and silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable.
Further, inorganic nitrides such as silicon nitride (Si ₃ N ₄ , SixNy (x, y> 0)) and aluminum nitride can also be suitably used.

Further, the insulator layer may be formed of a precursor containing an alkoxide metal, and the insulator layer is formed by coating a solution of the precursor on a substrate, for example, and subjecting the solution to a chemical solution treatment including heat treatment. It is formed.
The metal in the alkoxide metal is selected from, for example, a transition metal, a lanthanoid, or a main group element. Specifically, barium (Ba), strontium (Sr), titanium (Ti), bismuth (Bi), tantalum ( Ta), zircon (Zr), iron (Fe), nickel (Ni), manganese (Mn), lead (Pb), lanthanum (La), rubidium (Rb), cesium (Cs), francium (Fr), beryllium ( Examples include Be), magnesium (Mg), calcium (Ca), niobium (Nb), copper (Cu), cobalt (Co), rhodium (Rh), scandium (Sc), and yttrium (Y). Examples of the alkoxide in the alkoxide metal include, for example, alcohols including methanol, ethanol, propanol, isopropanol, butanol, isobutanol, methoxyethanol, ethoxyethanol, propoxyethanol, butoxyethanol, pentoxyethanol, heptoxyethanol, Examples thereof include those derived from alkoxy alcohols including methoxypropanol, ethoxypropanol, propoxypropanol, butoxypropanol, pentoxypropanol, heptoxypropanol, and the like.

In the present invention, when the insulator layer is made of the above-described material, polarization easily occurs in the insulator layer, and the threshold voltage for transistor operation can be reduced. Among the above materials, in particular, when an insulator layer is formed of silicon nitride such as Si ₃ N ₄ , SixNy, or SiONx (x, y> 0), a depletion layer is more likely to be generated, and the threshold of transistor operation is increased. The voltage can be further reduced.
As an insulator layer using an organic compound, polyimide, polyamide, polyester, polyacrylate, photo radical polymerization system, photo cation polymerization system photo-curable resin, copolymer containing acrylonitrile component, polyvinyl phenol, polyvinyl alcohol, Polysiloxane, polyurethane, novolac resin, melamine resin, cyanoethyl pullulan, and the like can also be used.

In addition, wax, polyethylene, polychloropyrene, polyethylene terephthalate, polyoxymethylene, polyvinyl chloride, polyvinylidene fluoride, polymethyl methacrylate, polysulfone, polycarbonate, polystyrene (PS), polyolefin, polyacrylamide, poly (acrylic acid), resole resin, In addition to polyxylylene and epoxy resin, it is also possible to use a polymer material having a high dielectric constant such as pullulan.
The organic material may be a fluororesin such as Cytop (registered trademark).

  Further, when a top gate structure as shown in FIG. 6 is used, if an organic compound such as a polyparaxylylene derivative or a fluororesin is used as a material for the insulator layer, damage to the organic semiconductor layer is reduced. This is an effective method because it can be formed into a film.

The insulator layer may be a mixed layer using a plurality of inorganic or organic compound materials as described above, or may be a laminated structure thereof. In this case, the performance of the device can be controlled by mixing or laminating a material having a high dielectric constant and a material having water repellency, if necessary.
The insulator layer may include an anodized film or the anodized film as a configuration. The anodized film is preferably sealed. The anodized film is formed by anodizing a metal that can be anodized by a known method. Examples of the metal that can be anodized include aluminum and tantalum, and the anodizing method is not particularly limited, and a known method can be used. An oxide film is formed by anodizing. Any electrolyte solution that can form a porous oxide film can be used as the anodizing treatment. Generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, boric acid, sulfamic acid, benzenesulfone, and the like can be used. An acid or the like, or a mixed acid obtained by combining two or more of these or a salt thereof is used. The treatment conditions for anodization vary depending on the electrolytic solution used, and thus cannot be specified in general. In general, the concentration of the electrolytic solution is 1% by mass or more and 80% by mass or less, and the temperature of the electrolytic solution is 5 ° C. or more and 70 ° C. A range of not more than ° C., a current density of 0.5 A / cm ² or more and 60 A / cm ² or less, a voltage of 1 to 100 volts, and an electrolysis time of 10 seconds to 5 minutes is appropriate. A preferred anodizing treatment is a method in which an aqueous solution of sulfuric acid, phosphoric acid or boric acid is used as the electrolytic solution and the treatment is performed with a direct current, but an alternating current can also be used. The concentration of these acids is preferably 5% by mass or more and 45% by mass or less, and the electrolyte temperature is 20 ° C. or more and 50 ° C. or less, and the current density is 0.5 A / cm ² or more and 20 A / cm ² or less for 20 seconds or more and 250%. The electrolytic treatment is preferably performed in the range of not more than seconds.
As the thickness of the insulator layer, if the layer thickness is thin, the effective voltage applied to the organic semiconductor increases, so the drive voltage and threshold voltage of the device itself can be lowered, but conversely between the source and gate. Therefore, it is necessary to select an appropriate film thickness. Usually, the thickness is from 10 nm to 5 μm, preferably from 50 nm to 2 μm, more preferably from 100 nm to 1 μm.

  Moreover, you may perform arbitrary orientation processing between the said insulator layer and an organic-semiconductor layer. A preferable example thereof is a method for improving the crystallinity of the organic semiconductor layer by reducing the interaction between the insulator layer and the organic semiconductor layer by performing a water repellent treatment on the surface of the insulator layer. Silane coupling agents such as hexamethyldisilazane, octadecyltrichlorosilane, trichloromethylsilazane, and self-organized alignment film materials such as alkane phosphoric acid, alkane sulfonic acid, and alkane carboxylic acid are insulated in the liquid phase or gas phase state. An example is a method in which the film is brought into contact with the surface of the film to form a self-assembled film, followed by appropriate drying treatment. Further, a method in which a film made of polyimide or the like is provided on the surface of the insulating film and the surface is rubbed so as to be used for liquid crystal alignment is also preferable.

  As a method for forming the insulator layer, a vacuum deposition method, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, JP-A-11-61406, 11-133205 gazette, JP-A 2000-121804 gazette, 2000-147209 gazette, 2000-185362 gazette, dry process such as atmospheric pressure plasma method, spray coating method, spin coating method, blade coating Examples include wet processes such as coating, dip coating, casting, roll coating, bar coating, and die coating, and methods such as printing and ink-jet patterning. The wet process is a method of applying and drying a liquid in which fine particles of inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as required, or an oxide precursor, for example, A so-called sol-gel method in which a solution of an alkoxide body is applied and dried is used.

The method for forming the organic thin film transistor of the present invention is not particularly limited and may be a known method. Preferably, the steps after the formation of the organic semiconductor layer are steps which are not exposed to the atmosphere. In addition, some p-type TFT materials are exposed to the atmosphere once, and the performance is improved by adsorbing oxygen or the like. Therefore, depending on the material, the materials are appropriately exposed to the atmosphere.
Furthermore, for example, in consideration of the influence on the organic semiconductor layer such as oxygen and water contained in the atmosphere, a gas barrier layer may be formed on the whole or a part of the outer peripheral surface of the organic transistor element. As the material for forming the gas barrier layer, those commonly used in this field can be used, and examples thereof include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, and polychlorotrifluoroethylene. . Furthermore, the inorganic substance which has the insulation illustrated in the said insulator layer can also be used.

  Examples of the apparatus using the organic thin film transistor of the present invention include electronic devices for display such as circuits, personal computers, displays, mobile phones, electronic devices used for thin film displays, wearable electronic devices such as plastic IC cards and information tags, biotechnology, and the like. Examples thereof include medical equipment such as sensors and measurement devices.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.
[Example 1]
After forming a gate electrode (material: gold) on a glass substrate (size: 40 mm × 40 mm) using a mask vapor deposition method, an insulating film material ILLUMIKA Type-ANL1 manufactured by Kaneka Co., Ltd. is applied and cured with a spin coater for insulation. A film was formed (hereinafter referred to as ANL1 insulating film). The surface free energy of this insulating film was 27 mN / m.
On this insulating film, a source electrode (material: gold) and a drain electrode (material: gold) were formed using a mask vapor deposition method. The distance between the source electrode and the drain electrode corresponding to the channel length is 20 μm, and the channel width is 100 μm. At the same time, gold was vapor-deposited on another part of the insulating film at 10 mm □, and the surface free energy was measured and found to be 35 mN / m.
Next, an electrode modification composition (ink) was prepared by mixing 4-trifluoromethylbenzenethiol having an ionization potential of 5.7 eV and ethylene glycol in a mass ratio of 1:99. The surface tension of this ink was 45 mN / m.
Ten drops of 10 pL of this ink were dropped at the center between the source electrode and the drain electrode using an ink jet apparatus. The droplet moved on the source and drain electrodes and dried on the source and drain electrodes. Furthermore, it heated at 100 degreeC for 10 minute (s), and the remaining solvent was dried. When the work function of this electrode was measured using the AC3 work function meter of Riken Keiki, the thiol group was chemically bonded to the gold electrode, and the work function of the electrode changed from 4.8 eV to 5.7 eV of gold. I was able to confirm. Thus, it was confirmed that the surface treatment (modification) of the electrode was completed.
The surface free energy of a processed product obtained by applying and drying this ink on the entire surface of 10 mm square gold formed on another part of the substrate was measured and found to be 33 mN / m. When the surface free energy of the insulating film in the region where the gold electrode was not formed was measured, there was no change at 27 mN / m. Thereby, after performing an electrode modification method, it has confirmed that the difference of the surface free energy of an electrode and the part between electrodes can be made small, and the applicability | paintability of organic-semiconductor ink can be improved.
Next, an organic semiconductor A represented by the following structural formula was synthesized with reference to International Publication No. 2011/074232. A mixture containing 1.8 mg of organic semiconductor A, 1.2 mg of polystyrene having a mass average molecular weight of 2,500 (manufactured by Aldrich) at a mass ratio of 85: 10: 5 mesitylene, 3,3,5-trimethylcyclohexanone, and N-methylpyrrolidone. A semiconductor ink was prepared by dissolving in a solvent to a total amount of 1 g.

This semiconductor ink was applied to the surface-treated substrate using a spin coater. After coating, the film was dried at 50 ° C. for 30 minutes, and further dried at 100 ° C. for 30 minutes to produce an organic thin film transistor.
A gate voltage of 0 to −30 V is applied to the gate electrode of the obtained organic thin film transistor, a current is applied by applying a voltage of −30 V between the source and the drain, and the threshold voltage (Vth) and field effect mobility (μ) are applied. Evaluated. The application of each voltage and the measurement of the current between the source and drain electrodes were performed using a semiconductor characteristic evaluation system (“4200SCS” manufactured by Keithley Instruments). When the characteristics of the obtained organic thin film transistor were measured, it was Vth = -3.6 V, μ = 1.5 cm ² / Vs, and on / off ratio = 9 × 10 ⁸ .

[Example 2]
In the same manner as in Example 1, a source electrode and a drain electrode mainly composed of silver were formed on the gate electrode and the ANL1 insulating film formed on the glass substrate by using the reverse printing method. The distance between the source electrode and the drain electrode corresponding to the channel length is 20 μm, and the channel width is 100 μm.
Next, as an electrode modifying composition (ink), 4-trifluoromethylbenzenethiol having an ionization potential of 5.7 eV, pentafluorobenzenethiol having an ionization potential of 5.5 eV, ethylene glycol, and isopropyl alcohol Were mixed at a mass ratio of 0.5: 0.5: 80: 19, respectively. The surface tension of this ink was 39 mN / m.
Ten drops of 10 pL of this ink were dropped at the center between the source electrode and the drain electrode using an ink jet apparatus. The droplet moved over the source and drain electrodes and dried on the source and drain electrodes. When the work function of this electrode was measured using an AC3 work function meter of Riken Keiki, the thiol group was chemically bonded to the gold electrode, and the work function of the electrode changed from 4.6 eV to 5.6 eV for silver. I was able to confirm. Thus, it was confirmed that the surface treatment (modification) of the electrode was completed.
An organic thin film transistor was produced in the same manner as in Example 1 except that an organic semiconductor B represented by the following structural formula was used instead of the organic semiconductor A used in Example 1, and the characteristics thereof were evaluated. The characteristics of the obtained organic thin film transistor were Vth = −0.7 V, μ = 0.9 cm ² / Vs, and on / off ratio = 1 × 10 ⁹ .

[Example 3]
In the same manner as in Example 1, a gate electrode, an ANL1 insulating film, a source electrode, and a drain electrode were formed on a glass substrate.
Next, as the electrode modifying composition (ink), 4-trifluoromethylbenzenethiol having an ionization potential of 5.7 eV, 1,3-propanediol, and ethyl lactate were added in a ratio of 1.5: 75: What was mixed by the mass ratio of 23.5 was prepared. The surface tension of this ink was 38 mN / m.
Ten drops of 10 pL of this ink were dropped at the center between the source electrode and the drain electrode using an ink jet apparatus. The droplet moved on the source and drain electrodes and dried on the source and drain electrodes. When the work function of this electrode was measured using the AC3 work function meter of Riken Keiki, the thiol group was chemically bonded to the gold electrode, and the work function of the electrode changed from 4.8 eV to 5.7 eV of gold. It was confirmed that Thus, it was confirmed that the surface treatment (modification) of the electrode was completed.
The organic semiconductor A used in Example 1 was formed on the surface-treated substrate by vacuum deposition to produce an organic thin film transistor. The characteristics of the obtained organic thin film transistor were Vth = −0.1 V, μ = 3.5 cm ² / Vs, and on / off ratio = 6 × 10 ⁹ .

[Comparative Example 1]
In the same manner as in Example 1, a gate electrode, an ANL1 insulating film, a source electrode, and a drain electrode were formed on a glass substrate.
Next, an electrode modification composition (ink) was prepared by mixing 4-trifluoromethylbenzenethiol having an ionization potential of 5.7 eV and mesitylene in a mass ratio of 1:99. The surface tension of this ink was 28 mN / m.
Ten drops of 10 pL of this ink were dropped at the center between the source electrode and the drain electrode using an ink jet apparatus. Part of the droplet moved to the source electrode and the drain electrode, but dried while remaining between the source electrode and the drain electrode. When the work function of this electrode was measured using an AC3 work function meter of Riken Keiki, it was confirmed that the work function of gold changed from 4.8 eV to 5.2 eV. This is probably because the surface treatment of the electrode became insufficient because the amount of the liquid moving on the electrode was small. That is, it was not possible to selectively modify only the surface of the electrode.
An organic semiconductor ink was applied to the surface-treated substrate in the same manner as in Example 1, and dried to produce an organic thin film transistor. The characteristics of the obtained organic thin film transistor were Vth = −6.7 V, μ = 0.04 cm ² / Vs, and on / off ratio = 1.2 × 10 ⁵ .
Since the surface treatment of the electrode was not sufficiently performed, good organic thin film transistor characteristics could not be obtained.

[Comparative Example 2]
In the same manner as in Example 1, a gate electrode, an ANL1 insulating film, a source electrode, and a drain electrode were formed on a glass substrate.
Next, an electrode modification composition (ink) was prepared by mixing 4-trifluoromethylbenzenethiol having an ionization potential of 5.7 eV and isopropyl alcohol at a mass ratio of 1:99. The surface tension of this ink was 22 mN / m.
Ten drops of 10 pL of this ink were dropped at the center between the source electrode and the drain electrode using an ink jet apparatus. The droplets dried quickly with little movement from the dropping position. When the work function of this electrode was measured using an AC3 work function meter of Riken Keiki, it was confirmed that the electrode function was changed from 4.8 eV to 5.1 eV. This is presumably because the surface treatment of the electrode became insufficient because the droplets dried before moving onto the electrode. That is, it was not possible to selectively modify only the surface of the electrode. In addition, this ink became unstable from the ink jet apparatus with time.
An organic semiconductor ink was applied to the surface-treated substrate in the same manner as in Example 1, and dried to produce an organic thin film transistor. The characteristics of the obtained organic thin film transistor were Vth = −18.6 V, μ = 1.1 × 10 ⁻³ cm ² / Vs, and on / off ratio = 2.2 × 10 ² .
Since 4-trifluoromethylbenzenethiol has a high boiling point of 192 ° C., 4-trifluoromethylbenzenethiol remaining in a large amount between the source and drain electrodes cannot be completely removed in the drying process, and the device characteristics are comparative examples. It is thought that it deteriorated to 1 or more.

DESCRIPTION OF SYMBOLS 1,1A ... Organic thin-film transistor 2 ... Composition for electrode modification 10 ... Substrate 11 ... Source electrode 12 ... Drain electrode 13 ... Organic-semiconductor layer 14 ... Insulator layer 14a ... Part between source electrode and drain electrode 15 ... Gate electrode 16 ... Modification part

Claims (15)

(A) a thiol compound having an ionization potential of 5.0 eV to 6.1 eV and (B) a solvent,
The component (B) includes an alcohol solvent (B1) having a boiling point of 150 ° C. or higher and 250 ° C. or lower,
The composition for electrode modification, wherein the surface tension of the composition is 30 mN / m or more and 50 mN / m or less. The composition for electrode modification according to claim 1,
The component (B) is a mixed solvent composed of two or more solvents, and the surface tension of the solvent having the highest boiling point among these two or more solvents is from 35 mN / m to 50 mN / m. An electrode modifying composition. In the electrode modification composition according to claim 1 or 2,
The surface modification energy of the electrode modified with said (A) component is 25 mN / m or more and 40 mN / m or less. The composition for electrode modification characterized by the above-mentioned. In the composition for electrode modification of any one of Claim 1 to Claim 3,
The concentration of said (A) component is 0.1 mass% or more and 10 mass% or less with respect to the composition whole quantity. The composition for electrode modification characterized by the above-mentioned. In the composition for electrode modification of any one of Claim 1 to Claim 4,
The component (A) is 4-trifluoromethylbenzenethiol, 3-trifluoromethylbenzenethiol, pentafluorobenzenethiol, 2,3,5,6-tetrafluorobenzenethiol, 2,3,5,6-tetra Fluoro-4- (trifluoromethyl) benzenethiol, 2,3,5,6-tetrafluoro-4-mercaptobenzoic acid methyl ester, 3,5-bistrifluoromethylbenzenethiol, 4-fluorobenzenethiol and 4-nitrobenzene It is at least 1 compound chosen from the group which consists of thiols. The composition for electrode modification characterized by the above-mentioned. In the composition for electrode modification according to any one of claims 1 to 5,
The compounding quantity of the said (B1) component is 50 mass% or more with respect to the said (B) component whole quantity. The composition for electrode modification characterized by the above-mentioned. In the composition for electrode modification according to any one of claims 1 to 6,
The component (B1) is 1,3-propanediol, 1,2-propanediol, ethylene glycol, 3-methoxy-1,2-propanediol, 1,2-butanediol, 1,3-butanediol, cyclohexane An electrode-modifying composition comprising at least one compound selected from the group consisting of hexanol, propyl lactate and ethyl lactate. In the electrode modification composition according to any one of claims 1 to 7,
The composition for electrode modification, wherein the component (B1) is a dihydric alcohol. In the electrode modification composition according to any one of claims 1 to 8,
The composition for electrode modification, wherein the component (B) further contains (B2) an alcohol solvent having a boiling point of less than 150 ° C. The composition for electrode modification according to claim 9,
The component (B2) is at least one solvent selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, pentanol and 1-methoxy-2-propanol. A composition for modifying an electrode. An electrode modification method for modifying the surface of at least one of a source electrode and a drain electrode in an organic thin film transistor,
Using the electrode modification composition according to any one of claims 1 to 10, by any one of a screen printing method, a reverse offset printing method, a flexographic printing method, and an inkjet printing method. An electrode modification method comprising modifying the electrode. An electrode modification method for modifying the surface of at least one of a source electrode and a drain electrode in an organic thin film transistor,
The organic thin film transistor has a structure in which the source electrode and the drain electrode face each other with an interval between them,
A step of attaching the electrode modifying composition according to any one of claims 1 to 10 on a substrate with an electrode having the source electrode and the drain electrode,
The electrode-attached substrate includes a surface free energy (SFE-S) of the source electrode, a surface free energy (SFE-D) of the drain electrode, and a surface free energy of a portion between the source electrode and the drain electrode ( The SFE-GI relationship satisfies at least one of the following formulas (F1) and (F2).
(SFE-GI) <(SFE-S) (F1)
(SFE-GI) <(SFE-D) (F2) In the electrode modification method according to claim 12,
An electrode modification method, wherein the electrode is modified by any one of a screen printing method, a reverse offset printing method, a flexographic printing method, and an ink jet printing method. In the electrode modification method according to any one of claims 11 to 13,
The organic thin film transistor is formed by a printing method. An electrode modification method, wherein: An organic thin film transistor having a substrate, a gate electrode, a source electrode, a drain electrode, an insulator layer, and an organic semiconductor layer,
The electrode modification method according to any one of claims 11 to 14, wherein at least one surface of the source electrode and the drain electrode is modified,
The surface free energy (SFE-S2) of the source electrode, the surface free energy (SFE-D2) of the drain electrode, and the portion between the source electrode and the drain electrode after the electrode modification by the electrode modification method. An organic thin film transistor characterized in that the surface free energy (SFE-GI2) relationship satisfies both the following mathematical formulas (F3) and (F4).
| (SFE-S2)-(SFE-GI2) | <10 mN / m (F3)
| (SFE-D2)-(SFE-GI2) | <10 mN / m (F4)

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