KR101535619B1 - Alkylated graphene oxide composition and field effect transistor type gas sensor comprising the same - Google Patents

Abstract

Organic semiconductors; And an alkylated-graphene oxide. ≪ Desc / Clms Page number 5 > The alkylated graphene oxide composition of the present invention can be used as an active layer, i.e., a sensing layer, of a field effect transistor type gas sensor. By using an organic semiconductor, a low processing cost can be realized, the organic semiconductor can be applied to a flexible substrate, and the organic semiconductor can be operated at room temperature. In addition, it is possible to omit the step of separately forming a receptor layer by forming an active layer with a complex of alkylated graphene oxide and a polymer semiconductor dispersed as a receptor material, and a receptor is present in a channel region of the transistor device to improve the sensitivity of the sensor There is an effect that can be.

Description

TECHNICAL FIELD The present invention relates to an alkylated graphene oxide composition and an electric field effect transistor type gas sensor including the alkylated graphene oxide composition and a field effect transistor type gas sensor including the alkylated graphene oxide composition.

The present invention relates to an alkylated graphene oxide composition and a field effect transistor type gas sensor comprising the same, and more particularly, to a composition comprising an alkylated graphene oxide and an organic semiconductor, and a field effect transistor type gas sensor .

When liver cirrhosis gets stiffened or contracted due to hepatocyte damage and increased connective tissue, the fatty acid component is included in the exhalation. When the function of the kidneys weakens, trimethylamine, a gas that smells of ammonia, is found. It has long been known that patients with lung cancer do not know why, but they have been known to exhale a mixture of alkanes and benzenes. The fact that the traces of the disease are left to be exacerbated is a basis for diagnosing the disease using the olfactory sensor.

In general, gas chromatography and mass spectrometers are used to accurately analyze gas components. However, this method is costly and complex, making it difficult to use it for commercial diagnosis. If olfactory sensors capable of sensing the various volatile organic compounds contained in the exhalation can be manufactured, the disease can be diagnosed with less accuracy but much simpler than the existing lung cancer diagnosis method. In the future, a medical revolution can occur that can diagnose many illnesses by breathing using the olfactory sensor, as in the case of using a breathalyzer to identify drivers who drink.

Sensors for analyzing gaseous components can be used to identify pollutants around us and collect / share data bases to enable cross-regional environmental monitoring through ubiquitous systems and to react instantly to chemical attacks in a terrorist or combat environment. And so on.

Over the past 25 years, organic semiconducting materials using monomolecular and polymeric materials have been making remarkable progress. Semiconductor materials using conventional inorganic materials have excellent characteristics and reliability, but they are gradually transferring their role to organic semiconductor materials due to the disadvantages of manufacturing cost and high operating temperature. to be. Organic semiconductor materials are easier to manufacture than inorganic semiconductor materials because they are simple to manufacture and can be manufactured at low cost in the fabrication of devices. Due to the nature of organic materials, it is easy to develop materials that exhibit superior characteristics through simple structure modification .

When such an organic semiconductor is used for a transistor-type gas sensor, a high sensing temperature is not required, and thus driving cost can be reduced. Therefore, it is necessary to develop a technology of a gas sensor with high sensitivity using the organic semiconductor.

In the sensing layer of the conventional transistor type gas sensor, a process of forming the receptor material as a separate layer on the semiconductor material is performed in order to improve the sensitivity of gas sensing. However, when the receptor layer is formed separately as described above, the process cost is increased and it is difficult to form a uniform thin film.

Korean Patent Publication No. 10-2011-0039803 Korean Patent No. 10-0477422

An object of the present invention is to solve the problems described above and to provide an organic semiconductor for an active layer of a field effect transistor gas sensor, which can realize a low process cost and can be applied to a flexible substrate and operate at room temperature.

In addition, the step of separately forming the receptor layer by introducing the receptor material in a dispersed form together with the organic semiconductor is omitted, and the alkylation of the gas sensing layer for the gas sensing layer, in which the receptor exists in the channel region of the transistor element, A pin oxide composition and a field effect transistor type gas sensor including the pin oxide composition as an active layer.

According to an aspect of the present invention, an organic semiconductor; And an alkylated-graphene oxide. ≪ Desc / Clms Page number 5 >

The alkylated graphene oxide may be 1 to 30 parts by weight based on 100 parts by weight of the organic semiconductor.

The alkylated graphene oxide composition may further comprise an organic solvent.

The organic semiconductor may be an amorphous organic semiconductor.

The organic semiconductor may be a p-type semiconductor.

The organic semiconductor may be selected from the group consisting of Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co-bithiophene], PBDTBO-TPDO (Poly [(5,6-dihydro- -4H-thieno [3,4-c] pyrrole-1,3-diyl) {4,8-bis [(2-butyloctyl) oxy] benzo [1,2- b: 4,5- b '] dthiophene- 2,6-diyl}], PBDT-TPD (Poly [[5- (2-ethylhexyl) -5,6-dihydro-4,6-dioxo-4H-thieno [3,4- 3-diyl] [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene-2,6-diyl]), PBDTTT- Synthesis of 1- (6- {4,8-bis [(2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4,5- bithiothiophen- methylthieno [3,4-b] thiophen-2-yl) -1-octanone]), PCDTBT (Poly [N-9'-heptadecanyl-2,7- -di-2-thienyl-2 ', 1', 3'-benzothiadiazole)], Poly [[9- (1-octylononyl) -9H-carbazole-2,7- 1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl), PCPDTBT (Poly [2,6- (4,4-bis- (2-ethylhexyl) -4H-cyclopenta [ ; 3,4-b '] dithiophene) -tallow-4,7 (2,1,3-benzothiadiazole)]), PFO-DBT (Poly [2,7- (9,9-dioctylfluorene) 7-bis (thiophen-2-yl) benzo-2,1,3-thiadiazole]), PTAA ( Poly [(5,6-dihydro-5-octyl-4,6-dioxo-4H-thieno [3,4-c] pyrrole-1,3-diyl) [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene-2,6-diyl] [(9,9-di-n-octylfluorenyl-2,7-diyl) -tallow- (benzo [2,1,3] thiadiazol-4,8-diyl]), P3DDT (Poly (3- dodecylthiophene- , 5-diyl), P3HT (Poly (3-hexylthiophene-2,5-diyl), MDMO-PPV (Poly [2-methoxy-5- (3 ', 7'- dimethyloctyloxy) ), MEH-PPV (Poly-2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene]), P3OT (Poly (3-octylthiophene- 2,6-dihydroxy-2 - [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene- carbonyl] thieno [3,4-b] thiophenediyl})).

Wherein the organic semiconductor is selected from the group consisting of TIPS-pentacene (6,13-bis (triisopropylsilylethynyl) pentacene), TES-Pentacene (6,13-Bis (triethylsilyl) ethynyl) pentacene, DH- (2,8-Difluoro-5,11-bis (triethylsilylethynyl) anthradithiophene), DH2T (5,5'-Dihexyl -2,2'-bithiophene), DH4T (3,3 '' - Dihexyl-2,2 ': 5', 2 '': 5 '', 2 '' '- quaterthiophene), DH6T '' '' -Dihexyl-2,2 ': 5', 2 '': 5 '', 2 '' ': 5' '', 2 ' -Sexthiophene), DTS (PTTh2) 2 (4,4 '- [4,4-Bis (2-ethylhexyl) -4H-silolo [3,2-b: 4,5- b'] dithiophene- -diyl] bis [7- (5'-hexyl- [2,2'-bithiophen-5-yl] - [1,2,5] thiadiazolo [3,4- c] pyridine] Bis {[4- (7-hexylthiophen-2-yl) thiophen-2-yl] - 1,2,5 thiadiazolo [3,4- c] pyridine} -3,3'- di- 2,2'-bithiophene), SMDPPEH (2,5-Di- (2-ethylhexyl) -3,6-bis- 5-yl) -pyrrolo [3,4-c] pyrrole-1,4-dione), and TES-ADT (5 , 11-bis (triethylsilylethynyl) anthradithiophene).

The alkylated graphene oxide may be one in which alkylamine is chemically bonded to graphene oxide to introduce an alkyl group.

The alkylamine may be a primary or secondary alkylamine.

The primary or secondary alkylamine may be one represented by the following structural formula (1).

[Structural formula 1]

In the above formula 1,

R ¹ and R ² may be the same or different from each other, R ¹ and R ² are each independently a hydrogen atom or a C 5 to C 30 saturated or unsaturated alkyl group,

R ¹ and R ² are not simultaneously hydrogen atoms.

The alkylamine may be at least one selected from the group consisting of oleylamine, hexylamine, and hexadecylamine.

The organic solvent may be at least one selected from the group consisting of chloroform, toluene, chlorobenzene, methyl ethyl ketone, p-xylene, acetone, ethanol, 1-propanol and 1-butanol.

According to another aspect of the present invention,

Oxidizing the graphite to produce graphene oxide (step a);

Reacting the graphene oxide with an alkylamine to produce an alkylated graphene oxide (step b); And

A step of adding and dispersing the alkylated graphene oxide prepared in step b and the organic semiconductor in an organic solvent (step c).

In step (b), a solution in which the graphene oxide is dispersed in water and a solution in which the alkylamine is dispersed in an organic solvent are mixed and stirred to react, and then the product is dried to produce an alkylated graphene oxide in powder form have.

The dispersion in step c may be performed by ultrasonic treatment.

According to another aspect of the present invention,

Organic semiconductors; And an active layer comprising an alkylated-graphene oxide-containing alkylated graphene oxide composition is provided. ≪ Desc / Clms Page number 2 >

The field effect transistor type gas sensor comprises:

A substrate including a gate electrode and a gate insulating layer disposed on the gate electrode;

The active layer disposed on the gate insulating layer; And

And source and drain electrodes spaced apart from each other on the active layer.

According to another aspect of the present invention,

Preparing a substrate including a gate electrode and a gate insulating layer disposed on the gate electrode (step 1); And

And forming an active layer on the gate insulating layer by coating an alkylated graphene oxide composition prepared by the method for preparing an alkylated graphene oxide composition (Step 2). do.

The coating in step 2 may be performed by any one method selected from the group consisting of spin coating, inkjet coating, dip coating, drop casting and bar coating Lt; / RTI >

And then performing a hydrophobic treatment on the gate insulating layer after the step 1.

The transistor-type gas sensor of the present invention can realize a low process cost by using an organic semiconductor in a sensing layer, can be applied to a flexible substrate, and can operate at room temperature.

In addition, the step of separately forming the receptor layer by introducing the receptor material in a form dispersed in the organic semiconductor can be omitted, and the receptor is present in the channel region of the transistor element, thereby improving the sensitivity of the sensor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a sequential process for producing an alkylated graphene oxide composition for a gas sensing layer of the present invention. FIG.
2 is a cross-sectional view schematically showing a structure of a field-effect transistor type gas sensor according to the present invention.
3 is a SEM photograph of the surface of the active layer of the field effect transistor type gas sensor manufactured according to the second embodiment of the present invention.
4 is a cross-sectional view schematically showing the structure of a field-effect transistor type gas sensor manufactured according to Example 2 (a) and Comparative Example 1 (b) of the present invention.
5 is a graph showing FTIR spectrum analysis results of graphene oxide prepared according to Preparation Example 1. FIG.
6 is a graph showing the FTIR spectrum analysis results of the alkylated graphene oxide produced according to Preparation Example 2. FIG.
7 is a photograph showing a state in which the graphene oxide (a) of Production Example 1 and the alkylated graphene oxide (b) of Production Example 2 are dispersed in an organic solvent.
8 is a result of measuring the water contact angle of (a) the organic semiconductor (F8T2), (b) the alkylated graphene oxide, and (c) the coating layer made of graphene oxide
FIG. 9 is a graph showing the relationship between I _D -V _G (a) and I _D -V _G measured for the reaction of the gas sensor according to Comparative Example 1 (a) and Example 2 It is a curve.
FIG. 10 is a graph showing the response of the gas sensor according to Comparative Example 1 (a) and Example 2 (a) to ammonium hydroxide vapor, I _D -V _G It is a curve.
11 is a graph showing the relationship between I _D -V _G (a) and I _{D- G} It is a curve.
12 is a graph showing the sensitivity of the gas sensor according to Comparative Example 1 and Example 2.

The invention is capable of various modifications and may have various embodiments, and particular embodiments are exemplified and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

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 the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

As used herein, unless otherwise defined, the term "alkyl group" means a straight, branched or cyclic aliphatic hydrocarbon group. The alkyl group may be a "saturated alkyl group" which does not contain any double or triple bonds.

The alkyl group may be an "unsaturated alkyl group" comprising at least one double bond or triple bond.

For example, the C1 to C4 alkyl groups may have 1 to 4 carbon atoms in the alkyl chain, i.e., the alkyl chain may be optionally substituted with one or more substituents selected from the group consisting of methyl, ethyl, propyl, iso-propyl, n-butyl, Indicating that they are selected from the group.

Specific examples of the alkyl group include a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, ethenyl group, Butyl group, cyclopentyl group, cyclohexyl group, and the like.

Hereinafter, the alkylated graphene oxide composition for the gas sensing layer of the present invention will be described.

The alkylated graphene oxide compositions for the gas sensing layer of the present invention include organic semiconductors and alkylated-graphene oxides.

The alkylated graphene oxide is preferably contained in an amount of 1 to 30 parts by weight based on 100 parts by weight of the organic semiconductor. More preferably 5 to 25 parts by weight, and even more preferably 7 to 15 parts by weight.

The alkylated graphene oxide composition may further comprise an organic solvent.

The organic semiconductor may include both amorphous and crystal semiconductors, but it is more preferably an amorphous organic semiconductor and more preferably a p-type semiconductor.

The organic semiconductor may be a polymer or a low molecular organic semiconductor.

The organic semiconductor can be used as an active layer of a transistor by using two or more kinds of polymers and a low-molecular organic semiconductor together, using different polymer-organic polymer semiconductors, or using different low-molecular-low molecular organic semiconductors together.

The polymeric organic semiconductors were synthesized from poly [(9,9-dioctylfluorenyl-2,7-diyl) -co-bithiophene], PBDTBO-TPDO (Poly [(5,6-dihydro- dioxo-4H-thieno [3,4-c] pyrrole-1,3-diyl) {4,8-bis [(2-butyloctyl) oxy] benzo [1,2- b: 4,5- b '] dithiophene -2,6-diyl}], PBDT-TPD (Poly [[5- (2-ethylhexyl) -5,6-dihydro-4,6-dioxo-4H-thieno [3,4- c] pyrrole- , 3-diyl] [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene-2,6-diyl]), PBDTTT- [1- (6- {4,8-bis [(2-ethylhexyl) oxy] -6-methylbenzo [1,2- b: 4,5- bithiothiophen-2-yl] -3-fluoro- -methylthieno [3,4-b] thiophen-2-yl) -1-octanone]), PCDTBT (Poly [N-9'-heptadecanyl-2,7- 2 ', 1'-benzothiadiazole)], Poly [[9- (1-octylononyl) -9H-carbazole-2,7-diyl] -2,5-thiophenediyl-2 , 1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]), PCPDTBT (Poly [2,6- (4,4-bis- (2-ethylhexyl) -4H- b, 3,4-b '] dithiophene) -tallow-4,7 (2,1,3-benzothiadiazole)]), PFO-DBT (Poly [2,7- (9,9-dioctylfluorene) , 7-bis (thiophen-2-yl) benzo-2,1,3-thiadiazole e]), Poly [(5,6-dihydro-5-octyl-4,6-dioxo-4H-thieno [ 3,4-c] pyrrole-1,3-diyl) [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5- b '] dithiophene- ], F8BT (Poly [(9,9-di-n-octylfluorenyl-2,7-diyl) -alt- (benzo [2,1,3] thiadiazol-4,8-diyl)], P3DDT (3-hexylthiophene-2,5-diyl), MDMO-PPV (Poly [2-methoxy-5- (3 ', 7'- dimethyloctyloxy) -1,4-phenylenevinylene], MEH-PPV (Poly [2-methoxy-5- (2-ethylhexyloxy) , PTB7 (Poly ({4,8-bis [(2-ethylhexyl) oxy] benzo [1,2-b: 4,5- b] dithiophene- (2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl})).

The low molecular weight organic semiconductors include TIPS-pentacene (6,13-bis (triisopropylsilylethynyl) pentacene), TES-Pentacene (6,13-Bis (triethylsilyl) ethynyl) pentacene, DH-FTTF (2,8-Difluoro-5,11-bis (triethylsilylethynyl) anthradithiophene), DH2T (5,5'- Dihexyl-2,2'-bithiophene), DH4T (3,3 '' - Dihexyl-2,2 ': 5', 2 '': 5 '', 2 '' '- quaterthiophene), DH6T 5 '', 2 '' ', 5' '', 2 '' '', 5 '' '', 2 '' ' -Sexthiophene), DTS (PTTh2) 2 (4,4 '- [4,4-Bis (2-ethylhexyl) -4H-silolo [3,2-b: 4,5- b'] dithiophene- 6-diyl] bis [7- (5'-hexyl- [2,2'-bithiophen-5-yl] - [1,2,5] thiadiazolo [ -Bis {[4- (7-hexylthiophen-2-yl) thiophen-2-yl] - [1,2,5] thiadiazolo [3,4-c] pyridine} -3,3'-di-2-ethylhexylsilylene -2,2'-bithiophene), SMDPPEH (2,5-Di- (2-ethylhexyl) -3,6-bis- (5'-n-hexyl- [2,2 ', 5' ] terthiophen-5-yl) -pyrrolo [3,4-c] pyrrole-1,4-dione), TES -Adt (5,11-bis (triethylsilylethynyl) anthradithiophene).

The alkylated graphene oxide means that the alkyl group is chemically covalently bonded to the graphene oxide and the alkylamine. Specifically, the acid group of graphene oxide and the amine group of alkylamine may be bonded to each other to introduce an alkyl group into graphene oxide.

The alkylamine may be a primary or secondary alkylamine.

Specifically, the alkylamine may be represented by the following structural formula (1).

[Structural formula 1]

In the above formula 1,

R ¹ and R ² may be the same or different from each other, R ¹ and R ² are each independently a hydrogen atom or a C 5 to C 30 saturated or unsaturated alkyl group,

R ¹ and R ² are not simultaneously hydrogen atoms.

Preferably, the alkylamine may be oleylamine, hexylamine, hexadecylamine, or the like.

The organic solvent may be chloroform, toluene, chlorobenzene, methyl ethyl ketone, p-xylene, acetone, ethanol, 1-propanol or 1-butanol. Two or more kinds of solvents may be used in a co- .

Hereinafter, a method for producing an alkylated graphene oxide composition for a gas sensor layer according to the present invention will be described with reference to FIG.

First, graphite is oxidized to prepare graphene oxide (step a).

The graphene oxide can be produced by a known hummers method, and the method is not particularly limited.

Next, the graphene oxide is reacted with an alkylamine to produce an alkylated graphene oxide (step b).

Specifically, a method may be used in which a solution in which the graphene oxide is dispersed in water and a solution in which the alkylamine is dispersed in an organic solvent are mixed and stirred to react and then the product is dried to obtain a powder, It does not. The synthesis of the alkylated graphene oxide may be varied depending on the kind of the alkylamine, and the production method is suitable for the use of oleylamine.

Thereafter, the alkylated graphene oxide prepared in step b and the organic semiconductor are added to the organic solvent and dispersed to prepare a complex (step c).

In order to promote the dispersion, ultrasonic treatment may be performed in step c.

Hereinafter, the structure of the field effect transistor type gas sensor of the present invention will be described with reference to FIG.

The field effect transistor type gas sensor of the present invention comprises an alkylated graphite oxide composition comprising an organic semiconductor and an alkylated-graphene oxide as an active layer.

Specifically, the field effect transistor type gas sensor comprises: a substrate 10 comprising a gate electrode 12 and a gate insulating layer 14 on the gate electrode; An active layer (20) disposed on the gate insulating layer (14) of the substrate (10); And a source electrode 30 and a drain electrode 40 which are spaced apart from each other on the active layer 20.

The gate electrode 12 may be formed of a conductive material such as n-type doped silicon, ITO, In ₂ O ₃ , SnO ₂ , ZnO, ZnO doped with Ga, ZnO doped with Al, or SnO ₂ doped with Sb Metal electrodes such as gold, aluminum, and platinum may be applied.

A gate insulating layer 14 is _{silica, Al 2 O 3, Ta 2} O 5, Y 2 O 3, La 2 O 3, HfO 2, Nb 2 O 3, ZrO 2 such as an insulating oxide and PVP (Polyvinylpyrrolidone), Cytop of ^TM , poly-styrene (PS), and poly (ethyleneterephthalate) (PET).

The active layer 20 is composed of the above-described alkylated graphene oxide composition for the sensing layer of the present invention, and a detailed description thereof will be referred to.

The source electrode 30 and the drain electrode 40 may be made of Au, Ag, Cu, Al, ITO, or the like. The gate electrode, the source and drain electrodes, the gate insulating layer and the active layer may have a suitable combination depending on the properties of the respective materials.

The structure of the transistor applied to the transistor-type gas sensor of the present invention can be applied to a known technology, so that a detailed description thereof will be omitted.

Although only a field-effect transistor gate sensor of the top contact bottom gate type is illustrated in FIG. 2, the present invention is not limited thereto. In some cases, an alkylated graphite oxide composition for a gas sensing layer of the present invention Various variations of applicable transistors can be applied.

However, it is more preferable to apply a top contact type bottom gate type or a bottom contact bottom gate type in which a channel region which is an active layer is exposed to the outside and is easily applied to a gas sensing layer.

Hereinafter, a method of manufacturing a field-effect transistor type gas sensor of the present invention will be described.

First, a substrate made of a gate electrode and a gate insulating layer on the gate electrode is prepared (step 1).

In some cases, a hydrophobic treatment process may be further performed on the gate insulating layer.

The hydrophobic treatment may be carried out by using a low molecular substance of a carbon chain having a silane group such as octadecyltrimethoxysilane (ODTS), octyltrichlorosilane (OTS) or hexamethyldisiloxane (HMDS), a fluorinated low molecular substance such as FDTS (perfluorodecyltrichlorosilane), or a polymer such as a hydrophobic Cytop Materials and the like can be used.

Since the substrate is the same as that described above, a detailed description thereof will be referred to.

Next, an alkylated graphite oxide composition for a gas sensing layer of the present invention is coated on the gate insulating layer of the substrate to form an active layer (step 2).

The coating can be performed by spin coating, inkjet printing, dip coating, drop casting, bar coating, etc., but is not limited thereto.

Hereinafter, the present invention will be described more specifically by way of examples. However, this is for illustrative purposes only, and thus the scope of the present invention is not limited thereto.

[Example]

The graphite was purchased from Alfa Aesar (LOT: K23U009).

Other chemicals were purchased from Sigma-Aldrich.

Manufacturing example  One: Grapina Oxide  Produce

5 g of graphite, 5 g of potassium persulfate (K ₂ S ₂ O ₈ ), 5 g of phosphorus pentoxide (P ₂ O ₅ ) and 20 ml of sulfuric acid (H ₂ SO ₄ ) were stirred at 80 to 85 ° C for 5 hours and then cooled to room temperature. 60 ml of sulfuric acid (H ₂ SO _{4 )} was further added while the temperature of the batch was maintained at 10 ° C, and the mixture was stirred for 5 minutes, and then stirred at 35 ° C for 2 days. After that, 200 ml of distilled water and 20 ml of hydrogen peroxide (H ₂ O ₂ ) were added in order, and the mixture was thoroughly stirred for about 1 to 2 hours to obtain a synthetic product. Then, the synthesis result was purified using a solution prepared by mixing hydrochloric acid and distilled water at a ratio of 1:10. Then, the supernatant was collected by centrifugation and vacuum evaporated to prepare graphene oxide powder.

Manufacturing example  2: alkylation Grapina Oxide  Produce

50 mg of graphene oxide obtained in Preparation Example 1 was dispersed in 8.5 ml of distilled water, mixed with oleylamine solution dispersed in ethanol, and vigorously stirred at room temperature for 24 hours. Thereafter, vacuum evaporation yielded the alkylated graphene oxide as a powder.

Example  1: alkylation Grapina Oxide  Preparation of composition

The alkylated graphene oxide prepared in Preparation Example 2 and F8T2 (Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co-bithiophene] were added to chloroform at a weight ratio of 9: 1 and ultrasonicated for 3 hours And uniformly dispersed to prepare an alkylated graphene oxide composition.

Example  2: Field effect  Manufacture of transistor type gas sensor

An n-type silicon wafer containing 3000 Å thick silicon oxide was prepared, washed with piranha solution (6: 4 H ₂ SO ₄ : H ₂ O ₂ ) and reformed with ODTS (octadecyltrimethoxysilane). Next, an alkylated graphene oxide composition containing alkylated graphene oxide and F8T2 in a weight ratio of 1: 9 was added and dispersed in 1.35 ml of chloroform to prepare a 0.2% coating solution, and the coating solution was coated on the ODTS- To form an active layer thin film having a thickness of 30 nm. At this time, the coating was performed by spin coating at 2000 rpm for 30 seconds. After formation of the active layer, a gold electrode was thermally deposited on the active layer to produce a field effect transistor type gas sensor.

FIG. 3 is a SEM photograph of the active layer included in the field effect transistor type gas sensor manufactured according to Example 2. FIG.

Comparative Example  1: a layer containing an organic semiconductor active layer Field effect  Transistor type gas sensor

A field-effect transistor type gas sensor was fabricated in the same manner as in Example 2 except that F8T2 alone was used instead of the alkylated graphene oxide composition of Example 1 as the active layer.

A sectional structure of the field effect transistor type gas sensor (a) manufactured in accordance with the second embodiment and the field effect transistor type gas sensor (b) manufactured according to the first comparative example is schematically shown in FIG.

[Test Example]

Test Example  One: FTIR  Spectrum analysis

FTIR spectrum analysis was performed to confirm the synthesis of the graphene oxide represented by the following structural formula 1 produced according to Production Example 1 and the alkylated graphene oxide represented by the following structural formula 2 produced according to Preparation Example 2, 5 and Fig. 6, respectively.

[Structural formula 2]

[Structural Formula 3]]

Referring to FIG. 5, it can be confirmed that the synthesis of graphene oxide is well performed. According to FIG. 6, the alkylation of graphene oxide is well performed, and the alkylated graphene oxide has various polar functional groups remaining, It was confirmed that it is a suitable material for use as a receptor.

Test Example  2: alkylation Grapina Oxide  Dispersion stability test for organic solvent

FIG. 7 is a graph showing the results of the measurement of the amount of graphene oxide dispersed in chloroform of the graphene oxide of Production Example 1 and the amount of the alkylated graphene oxide of Production Example 2 in various organic solvents (toluene, chloroform, chlorobenzene, acetone, ethanol, Xylene, and 1-butanol).

According to FIG. 7, graphene oxide before alkylation was not properly dispersed in an organic solvent, whereas alkylated graphene oxide was visually confirmed to have excellent dispersibility in various organic solvents.

These results indicate that the acid group of graphene oxide and the amine group of oleylamine are chemically bonded to introduce an alkylene group having a sufficient length into the graphene oxide, thereby increasing dispersion stability in an organic solvent such as chloroform. It has been found that the alkylation graphene oxide having a high dispersion stability can be easily dispersed in an organic solvent together with an organic semiconductor during the production of a field effect transistor to easily produce an organic semiconductor complex.

Test Example  3: Number Contact angle ( Water contact angle ) Measure

8 is a measurement result of a water contact angle of a coating layer formed of (a) the organic semiconductor (F8T2), (b) alkylated graphene oxide, and (c) graphene oxide.

Referring to FIG. 8, it can be confirmed that the organic semiconductor material exhibits hydrophobicity, the graphene oxide exhibits hydrophilicity, and the alkylated graphene oxide exhibits amphipathic properties. That is, the alkylated graphene oxide can be dispersed in an organic solvent and can be dispersed together with an organic semiconductor material to easily produce an organic semiconductor complex.

Test Example  4: Gas reaction measurement

(a) Comparative Example 1 (when only a sensing layer is used for an organic semiconductor), (b) Example 3 (when an organic semiconductor and an alkylated graphene oxide composite are used as a sensing layer) The response to the gas was measured and shown in FIG. 9 to FIG.

Here, FIG. 9 shows acetone vapor, FIG. 10 shows ammonium hydroxide vapor, and FIG. 11 shows the reaction upon exposure to ethanol vapor. The black solid line represents the I _D -V _G curve after exposure to gas, and the red dotted line represents the I _D -V _G curve after gas exposure.

Specifically, the sensor was connected to the probe station (KEITHLEY 2361) and adjusted to expose the gas sensor to the saturated vapor pressure of each gas and measure the drain current-to-gate voltage (I _D -V _G ) characteristics.

In the change of the curve, the drain voltage was fixed at -80 V, and the gate voltage was changed from 20 V to -80 V to measure the change of the current. I _D -V _G The curves were measured before and after gas exposure, and field-effect mobility and threshold voltage were calculated according to Equation 1 below.

[Formula 1]

I _D = μC _diel W / 2L (V _GS - V _th ) ²

Where I _D is the source-drain current, μ is the field-effect carrier mobility, C _diel is the capacitance per unit area of the insulating layer, V _GS is the source-gate voltage, and V _th is the threshold voltage .

9 to 11, it can be seen that the signal change after gas exposure was larger when a complex of alkylated graphene oxide and a polymer semiconductor, which is a receptor material, was used as the active layer, compared with the case where only the polymer semiconductor was used as the active layer.

Test Example  5: Sensitivity analysis of gas sensor

In Test Example 4, the rate of change of the field effect carrier mobility before and after exposure to gas and the rate of change of the threshold voltage were measured according to the following Expression 2 and Expression 3, and the sensitivity of the transistor type gas sensor manufactured according to Example 2 and Comparative Example 1 Were compared.

[Formula 1]

[Formula 2]

The sensitivity analysis results are shown in Table 1 and FIG. 12 below. In FIG. 12, the results of the field effect transistor type gas sensor of Comparative Example 1 are shown in a square, and the results of the field effect transistor type gas sensor of Example 2 are indicated by an asterisk.

Gas type division V _th rate of change (%)  μ change rate (%) Acetone Comparative Example 1 4.73 (1) 1.72 (1) Example 2 45.50 (9.62) 58.78 (34.17) Ammonia Comparative Example 1 6.72 (1) 10.81 (1) Example 2 270.29 (40.22) 52.39 (4.90) Ethanol Comparative Example 1 6.43 (1) 2.75 (1) Example 2 115.70 (18.00) 15.49 (5.63)

The numbers in parentheses are relative values of the signal change rate of Example 2 when the signal change rate of Comparative Example 1 is taken as 1.

According to Table 1 and FIG. 12, compared with the field effect transistor type gas sensor of Comparative Example 1 in which only the polymer semiconductor is applied as the active layer, the field effect transistor type gas sensor of Example 2 in which the complex of the polymer semiconductor and the alkylated graphene oxide is applied as the active layer It can be seen that the sensor is much more sensitive to gas exposure.

10: substrate 12: gate electrode
14: gate insulating layer 20: active layer
22: organic semiconductor 24: alkylated graphene oxide
30: source electrode 40: drain electrode

Claims (20)

Organic semiconductors; And
An alkylated-graphene oxide,
Alkylated graphene oxide compositions for use in field effect transistor type gas sensors. The method according to claim 1,
Wherein the alkylated graphene oxide is 1 to 30 parts by weight based on 100 parts by weight of the organic semiconductor. The method according to claim 1,
≪ / RTI > wherein the alkylated graphene oxide composition further comprises an organic solvent. The method according to claim 1,
RTI ID = 0.0 > 1, < / RTI > wherein the organic semiconductor is an amorphous organic semiconductor. The method according to claim 1,
Wherein the organic semiconductor is a p-type semiconductor. The method according to claim 1,
The organic semiconductor may be selected from the group consisting of Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co-bithiophene], PBDTBO-TPDO (Poly [(5,6-dihydro- -4H-thieno [3,4-c] pyrrole-1,3-diyl) {4,8-bis [(2-butyloctyl) oxy] benzo [1,2- b: 4,5- b '] dthiophene- 2,6-diyl}], PBDT-TPD (Poly [[5- (2-ethylhexyl) -5,6-dihydro-4,6-dioxo-4H-thieno [3,4- 3-diyl] [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene-2,6-diyl]), PBDTTT- Synthesis of 1- (6- {4,8-bis [(2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4,5- bithiothiophen- methylthieno [3,4-b] thiophen-2-yl) -1-octanone]), PCDTBT (Poly [N-9'-heptadecanyl-2,7- -di-2-thienyl-2 ', 1', 3'-benzothiadiazole)], Poly [[9- (1-octylononyl) -9H-carbazole-2,7- 1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl), PCPDTBT (Poly [2,6- (4,4-bis- (2-ethylhexyl) -4H-cyclopenta [ ; 3,4-b '] dithiophene) -tallow-4,7 (2,1,3-benzothiadiazole)]), PFO-DBT (Poly [2,7- (9,9-dioctylfluorene) 7-bis (thiophen-2-yl) benzo-2,1,3-thiadiazole]), PTAA ( Poly [(5,6-dihydro-5-octyl-4,6-dioxo-4H-thieno [3,4-c] pyrrole-1,3-diyl) [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene-2,6-diyl] [(9,9-di-n-octylfluorenyl-2,7-diyl) -tallow- (benzo [2,1,3] thiadiazol-4,8-diyl]), P3DDT (Poly (3- dodecylthiophene- , 5-diyl), P3HT (Poly (3-hexylthiophene-2,5-diyl), MDMO-PPV (Poly [2-methoxy-5- (3 ', 7'- dimethyloctyloxy) ), MEH-PPV (Poly-2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene]), P3OT (Poly (3-octylthiophene- 2,6-dihydroxy-2 - [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5-b '] dithiophene- carbonyl] thieno [3,4-b] thiophenediyl})). The alkylated graphene oxide composition according to claim 1, The method according to claim 1,
Wherein the organic semiconductor is selected from the group consisting of TIPS-pentacene (6,13-bis (triisopropylsilylethynyl) pentacene), TES-Pentacene (6,13-Bis (triethylsilyl) ethynyl) pentacene, DH- (2,8-Difluoro-5,11-bis (triethylsilylethynyl) anthradithiophene), DH2T (5,5'-Dihexyl -2,2'-bithiophene), DH4T (3,3 '' - Dihexyl-2,2 ': 5', 2 '': 5 '', 2 '''- quaterthiophene), DH6T '''' -Dihexyl-2,2 ': 5', 2 '': 5 '', 2 ''':5''', 2 ' -Sexthiophene), DTS (PTTh2) 2 (4,4 '- [4,4-Bis (2-ethylhexyl) -4H-silolo [3,2-b: 4,5- b'] dithiophene- -diyl] bis [7- (5'-hexyl- [2,2'-bithiophen-5-yl] - [1,2,5] thiadiazolo [3,4- c] pyridine] Bis {[4- (7-hexylthiophen-2-yl) thiophen-2-yl] - 1,2,5 thiadiazolo [3,4- c] pyridine} -3,3'- di- 2,2'-bithiophene), SMDPPEH (2,5-Di- (2-ethylhexyl) -3,6-bis- 5-yl) -pyrrolo [3,4-c] pyrrole-1,4-dione), and TES-ADT (5 , 11-bis (triethylsilylethynyl) anthradithiophene). The alkylated graphene oxide composition of claim 1, The method according to claim 1,
Wherein the alkylated graphene oxide is covalently bonded to an alkylamine in graphene oxide to introduce an alkyl group. 9. The method of claim 8,
Wherein said alkylamine is a primary or secondary alkylamine. ≪ RTI ID = 0.0 > 11. < / RTI > 10. The method of claim 9,
The alkylated graphene oxide composition of claim 1, wherein the primary or secondary alkylamine is represented by the following structural formula (1).
[Structural formula 1]

In the above formula 1,
R ¹ and R ² may be the same or different from each other, R ¹ and R ² are each independently a hydrogen atom or a C 5 to C 30 saturated or unsaturated alkyl group,
R ¹ and R ² are not simultaneously hydrogen atoms. 11. The method of claim 10,
Wherein the alkylamine is at least one member selected from the group consisting of oleylamine, hexylamine, and hexadecylamine. The method of claim 3,
Wherein the organic solvent is at least one selected from the group consisting of chloroform, toluene, chlorobenzene, methyl ethyl ketone, p-xylene, acetone, ethanol, 1-propanol and 1-butanol. Oxidizing the graphite to produce graphene oxide (step a);
Reacting the graphene oxide with an alkylamine to produce an alkylated graphene oxide (step b); And
(C) placing and dispersing the alkylated graphene oxide and the organic semiconductor prepared in step b in an organic solvent,
A method for producing an alkylated graphene oxide composition for use in a field effect transistor type gas sensor. 14. The method of claim 13,
The step b is a step of mixing and stirring a solution of the graphene oxide in water and a solution of the alkylamine dispersed in an organic solvent to react and then drying the product to prepare an alkylated graphene oxide in powder form ≪ RTI ID = 0.0 > 1, < / RTI > 14. The method of claim 13,
≪ / RTI > wherein said dispersion of step c is performed by ultrasonic treatment. Organic semiconductors; And an alkylated graphite oxide composition comprising an alkylated graphite oxide and an alkylated-graphene oxide. ≪ Desc / Clms Page number 13 > 17. The method of claim 16, wherein the field effect transistor type gas sensor
A substrate including a gate electrode and a gate insulating layer disposed on the gate electrode;
The active layer disposed on the gate insulating layer; And
A source electrode and a drain electrode spaced apart from each other on the active layer;
Wherein the sensor is a gas sensor. Preparing a substrate including a gate electrode and a gate insulating layer disposed on the gate electrode (step 1); And
Coating an alkylated graphene oxide composition prepared according to claim 13 on the gate insulating layer to form an active layer (step 2);
Wherein the method comprises the steps of: 19. The method of claim 18,
Wherein the coating in step 2 is performed by any one method selected from the group consisting of spin coating, ink jet printing, dip coating, drop casting and bar coating. 19. The method of manufacturing a field effect transistor type gas sensor according to claim 18,
Further comprising the step of subjecting the gate insulating layer to a hydrophobic treatment after the step (1). ≪ RTI ID = 0.0 > 11. < / RTI >

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