KR102205569B1 - Electrically stable organic electrolyte-gated transistors and their fabrication method - Google Patents

Abstract

The present invention relates to an organic transistor and a manufacturing process thereof, and more particularly, to an organic transistor including a polymer semiconductor layer including an ionic liquid, and a manufacturing process thereof.

Description

Electrically stable ionic electrolyte-based organic transistor and its manufacturing process {ELECTRICALLY STABLE ORGANIC ELECTROLYTE-GATED TRANSISTORS AND THEIR FABRICATION METHOD}

The present invention relates to an organic transistor and a manufacturing process thereof, and more particularly, to an electrically stable ionic electrolyte-based organic transistor and a manufacturing process thereof.

Ioinc liquids (ILs) are substances that have a melting point of 100℃ or less consisting of only cations and anions. Cations and anions constituting ionic liquids are generally large in size and often asymmetric, and are used in many industrial fields due to their characteristics such as low volatility, thermal stability, high ionic conductivity, and high electrochemical stability.

In particular, it has high electric capacity and ionic conductivity, so it is applied to various electrochemical devices such as transistors, actuators, secondary batteries, electrolytic capacitors, and dye-sensitized solar cells.

However, when the ionic liquid is directly applied to the device, there is a risk of leakage due to the characteristics of the liquid. In order to overcome these limitations, a polymer electrolyte forming a three-dimensional network structure may be added to the ionic liquid to prepare a polymer electrolyte called an ionic gel in a solid state having the above excellent characteristics. Representative ionic gel materials include a combination of P(VDF-HFP)/[EMIM][TFSI]. Ion gels maintain high thermal, chemical, and electrochemical stability while maintaining excellent electrical properties of ionic liquids and mechanical properties of polymers. Shows.

In a conventional ionic electrolyte-based organic transistor, when an electric field is formed in the organic transistor, cations and anions are oriented at both interfaces of the electrolyte layer, respectively. In this process, a reaction in which cations or anions penetrate into the polymer semiconductor layer inevitably occurs, and this ion penetration reaction continuously dope the semiconductor. The electrochemically doped device according to the ion permeation reaction has a fatal limitation in that it is difficult to maintain a stable current level when the device is repeatedly operated and the life of the device cannot be sustained for a long time.

In addition, the conventional ionic electrolyte based organic transistor is a system that induces high charge density in a polymer semiconductor by using an ionic electrolyte with a high capacitance as a gate dielectric. Continuous ions from the ionic electrolyte layer to the semiconductor active layer Due to the infiltration reaction, the drain current in the reverse driving is higher than the drain current in the forward driving, resulting in a greater hysteresis. Accordingly, when the device is repeatedly driven about 150 times, the mobility of the transistor is reduced to about 70%.

An object of the present invention is to provide an electrically stable ionic electrolyte-based organic transistor manufacturing process in order to overcome the above problems and limitations.

In addition, an object of the present invention is to provide an electrically stable ionic electrolyte-based organic transistor.

The manufacturing process of an organic transistor for an object of the present invention comprises: preparing a substrate on which source and drain electrodes are deposited; Preparing an ionic liquid solution and a polymer semiconductor solution; Mixing the ionic liquid solution and the polymer semiconductor solution; Coating the mixed mixture on a substrate to form a polymer semiconductor layer; Forming a dielectric layer on the polymer semiconductor layer; And forming a gate electrode on the dielectric layer.

In one embodiment, the ionic liquid solution is a solution in which an ionic liquid and an organic solvent are mixed.

In one embodiment, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium chloride.

In one embodiment, the organic solvent may include acetone, chloroform, ethanol, and dichloromethane.

In one embodiment, the polymer semiconductor solution is a solution in which a polymer semiconductor and an organic solvent are mixed.

In one embodiment, the polymer semiconductor is poly(hexyl-thiophene) (P3HT), poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene](PBTTT), poly[ bis(3-dodecyl-2-thienyl)-2,2'-dithiophene -5,5'-diyl](PQT-12), poly(9,9-dioctylfluorene-alt-benzothiadiazole)(F8BT), poly(naphthalenetetracarboxylic) diimide) (PNDI).

In an embodiment, the organic solvent may include chloroform, toluene, chlorobenzene, and dichlorobenzene.

In one embodiment, the dielectric layer may be an ionic gel, and the ionic gel is a mixture of an ionic liquid and a matrix polymer.

In one embodiment, the dielectric layer may be a liquid electrolyte.

In one embodiment, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium chloride.

In one embodiment, the polymer matrix includes P (VDF-HFP) (poly (vinylidene fluoride-co-hexafluoropropylene)), PVDF (poly (vinylidene fluoride)), PMMA (poly (methyl methacrylate)), PS (polystyrene) can do.

In one embodiment, the liquid electrolyte may include an ionic liquid or an ionic solution.

In one embodiment, the dielectric layer may be coated by a method including spin coating, bar coating, spray coating, drop casting, dip coating, and printing.

An organic transistor for another object of the present invention includes a substrate on which source and drain electrodes are deposited; A polymer semiconductor layer formed on the substrate; A dielectric layer formed on the polymer semiconductor layer; And a gate electrode formed on the dielectric layer, and the polymer semiconductor layer is made of a mixture of a polymer semiconductor and an ionic liquid.

In one embodiment, the polymer semiconductor is poly(hexyl-thiophene) (P3HT), poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene](PBTTT), poly[ bis(3-dodecyl-2-thienyl)-2,2'-dithiophene -5,5'-diyl](PQT-12), poly(9,9-dioctylfluorene-alt-benzothiadiazole)(F8BT), poly(naphthalenetetracarboxylic) diimide) (PNDI).

In one embodiment, the dielectric layer may be an ionic gel, and the ionic gel is a mixture of an ionic liquid and a matrix polymer.

In one embodiment, the dielectric layer may be a liquid electrolyte.

In one embodiment, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium chloride.

In one embodiment, the polymer matrix includes P (VDF-HFP) (poly (vinylidene fluoride-co-hexafluoropropylene)), PVDF (poly (vinylidene fluoride)), PMMA (poly (methyl methacrylate)), PS (polystyrene) can do.

In one embodiment, the liquid electrolyte may include an ionic liquid or an ionic solution.

The electrically stable ionic electrolyte-based organic transistor of the present invention forms a polymer semiconductor layer by mixing a polymer semiconductor and an ionic liquid, so that the polymer semiconductor layer can maintain a neutral charge state, and from the dielectric layer due to the neutral charge state As it has resistance to the ion penetration reaction of, excellent electrical stability can be expected.

In addition, the organic transistor may be combined with various monomolecular and polymeric semiconductor materials to show the possibility of continuous application.

1 is a flowchart of an organic transistor manufacturing process according to an exemplary embodiment of the present invention.
2 is a schematic diagram of a structure of an organic transistor manufactured according to an embodiment of the present invention.
3 is a schematic diagram of a manufacturing process of an organic transistor according to an embodiment of the present invention.
4 is an enlarged schematic diagram of a polymer semiconductor layer of an organic transistor manufactured according to an embodiment of the present invention.
5 is a view showing a drain current-gate voltage characteristic graph of an organic transistor according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present invention, various modifications may be made and various forms may be applied, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form of disclosure, it is to be understood as including all changes, equivalents, or substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals have been used for similar elements.

The terms used in the present application are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the existence of features, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other features or steps It is to be understood that it does not preclude the possibility of addition or presence of, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

An organic transistor manufacturing process according to an embodiment of the present invention includes: preparing a substrate on which source and drain electrodes are deposited; Preparing an ionic liquid solution and a polymer semiconductor solution; Mixing the ionic liquid solution and the polymer semiconductor solution; Coating the mixed mixture on a substrate to form a polymer semiconductor layer; Forming a dielectric layer on the polymer semiconductor layer; And forming a gate electrode on the dielectric layer.

1 is a flowchart of a manufacturing process of an organic transistor according to an embodiment of the present invention.

According to FIG. 1, preparing a substrate on which source and drain electrodes are deposited (S100), preparing an ionic liquid solution and a polymer semiconductor solution (S200), mixing the ionic liquid solution and the polymer semiconductor solution (S300), forming a polymer semiconductor layer by coating the mixed mixture on a substrate (S400), forming a dielectric layer on the polymer semiconductor layer (S500), and forming a gate electrode on the dielectric layer It includes step S600.

In step S100, a substrate on which source and drain electrodes are deposited is prepared. The source and drain electrodes may include titanium (Ti) or gold (Au).

When the source and drain electrodes are titanium, the thickness of the titanium is preferably 3 nm. When the source and drain electrodes are gold, the thickness of the gold is preferably 37 nm.

In step S 200, an ionic liquid solution and a polymer semiconductor solution are prepared. The ionic liquid solution may be a mixture of an ionic liquid and an organic solvent. The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium chloride. The organic solvent is acetone, chloroform, ethanol ( ethanol) and dichloromethane. The ionic liquid and the organic solvent are dissolved in a volume ratio of 1:5 to 1:100, and the ionic liquid may be used as a process additive after dissolving in a certain amount in a solvent.

The polymer semiconductor solution may be a mixture of a polymer semiconductor and an organic solvent. The polymer semiconductor is poly(hexyl-thiophene)(P3HT), poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene](PBTTT), poly[bis(3- dodecyl-2-thienyl)-2,2'-dithiophene -5,5'-diyl](PQT-12), poly(9,9-dioctylfluorene-alt-benzothiadiazole)(F8BT), poly(naphthalenetetracarboxylic diimide)(PNDI ) Can be included. The organic solvent may include chloroform, toluene, chlorobenzene, and dichlorobenzene. The polymeric semiconductor and the organic solvent are characterized by dissolving at a concentration of 2 mg/ml to 50 mg/ml.

In step S300, the ionic liquid solution prepared above and the polymer semiconductor solution are mixed. It is characterized in that the mixture is prepared by mixing the ionic liquid solution in a ratio of 0% to 90% based on the volume of the polymer semiconductor solution.

In step S400, the mixture is coated on a substrate to form a polymer semiconductor layer.

In step S500, a dielectric layer is formed on the polymer semiconductor layer. The dielectric layer may be an ionic gel, and the ionic gel may be a mixture of an ionic liquid and a matrix polymer. The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium chloride. The polymer mattress is P (VDF-HFP) (poly(vinylidene fluoride- co-hexafluoropropylene)), PVDF (poly(vinylidene fluoride)), PMMA (poly(methyl methacrylate)), PS (polystyrene). The polymer matrix, the ionic liquid, and the organic solvent are mixed at a mass ratio of 1:4:7, and stirred at a temperature of 60°C to 100°C for about 2 hours or more to prepare an ionic gel. The organic solvent may include acetone and butyl acetate. The prepared ionic gel is coated on the polymer semiconductor layer. The ionic gel may be coated by a method including spin coating, bar coating, spray coating, drop casting, dip coating, and printing.

The dielectric layer may be a liquid electrolyte. The liquid electrolyte may include an ionic liquid or an ionic solution. The liquid electrolyte is coated on the polymer semiconductor layer. The liquid electrolyte may be coated by a method including drop casting, spray coating, and dip coating.

In step S600, a gate electrode is formed on the dielectric layer. The gate electrode may include a conductive polymer, a metal electrode, and a metal nanostructure. The conductive polymer may include PEDOT:PSS.

An organic transistor for another object of the present invention includes a substrate on which source and drain electrodes are deposited; A polymer semiconductor layer formed on the substrate; A dielectric layer formed on the polymer semiconductor layer; And a gate electrode formed on the dielectric layer, and the polymer semiconductor layer is made of a mixture of a polymer semiconductor and an ionic liquid.

2 is a diagram illustrating a structure of an organic transistor manufactured according to an embodiment of the present invention.

Referring to FIG. 2, a substrate [10] on which source and drain electrodes are deposited, a polymer semiconductor layer [20] formed on the substrate, a dielectric layer [30] formed on the polymer semiconductor layer, and a gate electrode [40] on the dielectric layer. Is formed, and the polymer semiconductor layer is characterized in that it is made of a mixture of a polymer semiconductor and an ionic liquid.

The source and drain electrodes of the substrate 10 on which the source and drain electrodes are deposited may include titanium (Ti) or gold (Au). When the source and drain electrodes are titanium, the thickness of the titanium is preferably 3 nm. When the source and drain electrodes are gold, the thickness of the gold is preferably 37 nm.

The polymer semiconductor layer [20] formed on the substrate is characterized in that it is made of a mixture of a polymer semiconductor and an ionic liquid. The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium chloride. The polymer semiconductor is poly(hexyl-thiophene) (P3HT), poly[ 2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene](PBTTT), poly[bis(3-dodecyl-2-thienyl)-2,2'-dithiophene -5, 5'-diyl] (PQT-12), poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), and poly(naphthalenetetracarboxylic diimide) (PNDI).

The dielectric layer 30 formed on the polymer semiconductor layer may be an ionic gel, and the ionic gel may be a mixture of an ionic liquid and a matrix polymer. The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium chloride. The polymer mattress is P (VDF-HFP) (poly(vinylidene fluoride- co-hexafluoropropylene)), PVDF (poly(vinylidene fluoride)), PMMA (poly(methyl methacrylate)), PS (polystyrene).

The dielectric layer [30] may be of an entire liquid quality. The liquid electrolyte may include an ionic liquid or an ionic solution.

The gate electrode 40 formed on the dielectric layer may include a conductive polymer, a metal electrode, and a metal nanostructure. The conductive polymer may include PEDOT:PSS.

Example

Organic transistor manufacturing

3 is a diagram illustrating a process of manufacturing an organic transistor according to an embodiment of the present invention.

3, a substrate on which source and drain electrodes are deposited is prepared. Gold is used for the source and drain electrodes. An ionic liquid solution is prepared by dissolving the ionic liquid in an acetone organic solvent at a volume ratio of 10:1. A polymer semiconductor solution was prepared by dissolving the polymer semiconductor P3HT at a concentration of 10 mg/mL in a chloroform organic solvent. A mixed solution is prepared by adding the ionic liquid solution in a ratio of 5% to the volume of the polymer semiconductor solution. A polymer semiconductor layer is formed on the substrate on which the source and drain electrodes are deposited using the mixed solution.

A mixture was prepared by mixing the polymer matrix P (VDF-HFP), an ionic liquid, and an acetone organic solvent in a mass ratio of 1:4:7. The mixture is stirred at 80° C. for 2 hours or more to prepare an ionic gel. The ion gel is spin-coated on the polymer semiconductor layer to form a dielectric layer.

A gate electrode is formed on the dielectric layer. PEDOT:PSS, a conductive polymer, is used as the gate electrode.

Drain current-gate voltage characteristic test

4 is an enlarged schematic diagram of a polymer semiconductor layer of an organic transistor manufactured according to an embodiment of the present invention.

According to FIG. 4, when the polymer semiconductor layer of the organic transistor manufactured according to the manufacturing process of the present invention is enlarged, the polymer semiconductor layer contains an ionic liquid to maintain a neutral state of charge, through which ion penetration from the dielectric layer. It can be seen that it can have resistance to reaction.

5 is a diagram illustrating a graph of a drain current-gate voltage characteristic of an organic transistor according to an embodiment of the present invention.

Referring to FIG. 5, (a) is an organic transistor including a P3HT-based polymer semiconductor layer without adding an ionic liquid, and (b) is an ionic liquid solution in which acetone and [EMIM] [TFSI] ionic liquid are dissolved. An organic transistor including a 5 vol% added P3HT+[EMIM][TFSI]-based polymer semiconductor layer, (c) is a charge mobility according to the number of repetitive driving of a P3HT-based organic transistor and a P3HT/Ac-IL-based organic transistor. It is a change comparison.

According to (a), when the polymer semiconductor layer does not contain an ionic liquid, the drain current in the reverse driving is higher than the drain current in the forward driving due to the continuous ion permeation reaction from the dielectric layer to the polymer semiconductor active layer, resulting in hysteresis. Big.

According to (b), when the polymer semiconductor layer contains an ionic liquid, ion penetration reaction from the dielectric layer to the polymer semiconductor active layer is prevented, so there is no significant difference between the drain current in forward driving and the drain current in reverse driving. Can be seen.

According to (c), when the polymer semiconductor layer does not contain an ionic liquid, the mobility of the organic transistor is reduced by about 70% when the device is repeatedly driven 150 times, but the polymer semiconductor layer contains an ionic liquid. In this case, it can be seen that the mobility of the organic transistor is slightly reduced.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention described in the following claims. You will understand that you can.

10: substrate
20: polymer semiconductor layer
30: dielectric layer
40: gate electrode

Claims (20)

Preparing a substrate on which source and drain electrodes are deposited;
Preparing a first ionic liquid solution and a polymer semiconductor solution;
Mixing the first ionic liquid solution and the polymer semiconductor solution;
Coating the mixed mixture on a substrate to form a polymer semiconductor layer;
Forming a dielectric layer on the polymer semiconductor layer by using a dielectric solution including a second ionic liquid solution; And
Forming a gate electrode on the dielectric layer,
The first and second ionic liquids,
1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-butyl-3-methylimidazolium chloride,
The polymer semiconductor,
Including any one selected from poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) and poly(naphthalenetetracarboxylic diimide) (PNDI),
The dielectric layer is characterized in that the liquid electrolyte,
Organic transistor manufacturing process.
delete delete delete delete delete delete delete delete delete delete delete The method of claim 1,
The dielectric layer is
It is characterized in that it is coated by a method including any one selected from spin coating, bar coating, spray coating, drop casting, dip coating and printing,
Organic transistor manufacturing process.
A substrate on which source and drain electrodes are deposited;
A polymer semiconductor layer formed on the substrate;
A dielectric layer formed on the polymer semiconductor layer; And
A gate electrode is formed on the dielectric layer,
The polymer semiconductor layer is made of a mixture of a polymer semiconductor and a first ionic liquid,
The dielectric layer is characterized in that it is made of a mixture containing a second ionic liquid,
The first and second ionic liquids,
1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-butyl-3-methylimidazolium chloride,
The polymer semiconductor,
Including any one selected from poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) and poly(naphthalenetetracarboxylic diimide) (PNDI),
The dielectric layer is characterized in that the liquid electrolyte,
Organic transistor. delete delete delete delete delete delete

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