KR20220136152A - Hydrogen gas sensor - Google Patents

Abstract

The present invention relates to a hydrogen gas sensor. More specifically, the hydrogen gas sensor has rapid response speed and high selectivity with respect to hydrogen gas at room temperature without an additional heating means and is capable of sensing the hydrogen gas of low concentration at high sensitivity. According to the present invention, the hydrogen gas sensor comprises: a tin oxide layer; a first electrode and a second electrode spaced from each other on the tin oxide layer; a palladium nanoparticle layer positioned in an area where the first electrode and the second electrode are spaced; and a polymer layer positioned on the tin oxide layer and the palladium nanoparticle layer. The polymer layer is a hydrogen-selective polyimide film having a hydrogen permeability coefficient of 10 Barrer or more.

Description

Hydrogen gas sensor

The present invention relates to a hydrogen gas sensor, and more particularly, to a hydrogen gas sensor having a fast response speed and high selectivity to hydrogen gas at room temperature without a separate heating means, and capable of high sensitivity sensing even of a low concentration of hydrogen gas.

Hydrogen energy, which is emerging due to the recent depletion of fossil fuels and environmental pollution, is likely to be used in almost all fields used in the current energy system, from basic industrial materials to general fuels, hydrogen vehicles, hydrogen-powered airplanes, fuel cells, and nuclear fusion energy. has a

However, since hydrogen gas has a wide explosive concentration range (4 to 75%) and small ignition energy, it can be easily ignited even by minute static electricity, so even a small amount of leakage can be very dangerous. Accordingly, a high-performance sensor capable of quickly and accurately detecting hydrogen gas is required in order to reduce major accidents and human damage caused by hydrogen leakage.

Until now, sensors using catalytic combustion or hot wires, SiO2, AlN metal oxide (nitride) semiconductors, and sensors using a Schottky barrier diode with a bipolar structure using SiC, GaN, etc. in bulk Pd and Pt, etc. Various hydrogen gas sensors have been developed, but they are large in size and complicated in structure, and are expensive. In addition, since it operates at a high temperature of 300°C or higher, it has limitations such as not only high power consumption but also low sensitivity to hydrogen.

Accordingly, as disclosed in Korean Patent Publication No. 10-0870126 'Method for manufacturing hydrogen gas sensor using Pd nanowires', research on materials and structures for hydrogen gas sensors that can optimize performance as a hydrogen gas sensor is in progress. However, it is still necessary to develop a sensor that operates to have high sensitivity to hydrogen gas at room temperature.

(Patent Document 1): Republic of Korea Patent Publication No. 10-0870126

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydrogen gas sensor that has a fast response speed and high selectivity to hydrogen gas even at room temperature, and is capable of high sensitivity sensing even for a low concentration of hydrogen gas.

Another object of the present invention is to provide a hydrogen gas sensor having reliability and long-term stability of sensing hydrogen gas.

Another object of the present invention is to provide a method for manufacturing a hydrogen gas sensor capable of high sensitivity hydrogen sensing with high selectivity and sensitivity to hydrogen gas even at room temperature, and to provide a commercially available method for manufacturing a hydrogen gas sensor.

A hydrogen gas sensor according to the present invention includes a tin oxide layer; a first electrode and a second electrode spaced apart from each other on the tin oxide layer; a palladium nanoparticle layer positioned in a region where the first electrode and the second electrode are spaced apart; and a polymer layer positioned on the tin oxide layer and the palladium nanoparticle layer, wherein the polymer layer is a hydrogen-selective polyimide film having a hydrogen permeability coefficient of 10 Barrer or more.

In the hydrogen gas sensor according to an embodiment of the present invention, the polyimide may include (a) at least one diamine represented by the following Chemical Formula 1; And (b) BCDA (Bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride); can be prepared by polymerizing the monomer composition consisting of.

[Formula 1]

(In Formula 1,

,

,

또는

이고,A is

,

,

or

ego,

Here, R ¹ is hydrogen and 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl,

Each of R ² and R ³ is hydrogen, 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl, or adjacent R ² and R ³ are linked together to form a single bond can do,

Wherein B is a single bond, halogen-substituted or unsubstituted C _1-3 linear or branched alkylene, halogen-substituted or unsubstituted C _2-4 alkenylene, -S-, -(S=O )-, -(O=S=O)-, -CR4R5-, or -OZO-,

Here, R ⁴ and R ⁵ are taken together to form a C _3-10 cycloalkyl or C _5-20 aryl, which is unsubstituted or substituted with C _1-3 straight-chain or branched alkyl or halogen,

이고,Wherein Z is phenylene,

ego,

Wherein X is a single bond, or halogen-substituted or unsubstituted C _1-3 straight-chain or branched alkylene, and

wherein Y is C _1-3 straight-chain or branched alkylene substituted or unsubstituted with halogen).

In the hydrogen gas sensor according to an embodiment of the present invention, the polyimide may include (a) at least one diamine represented by the following Chemical Formula 1; and (b) 4,4′-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA); may be prepared by polymerizing a monomer composition consisting of.

[Formula 1]

(In Formula 1,

,

,

또는

이고,A is

,

,

or

ego,

Here, R ¹ is hydrogen and 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl,

Each of R ² and R ³ is hydrogen, 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl, or adjacent R ² and R ³ are linked together to form a single bond can do,

Wherein B is a single bond, halogen-substituted or unsubstituted C _1-3 linear or branched alkylene, halogen-substituted or unsubstituted C _2-4 alkenylene, -S-, -(S=O )-, -(O=S=O)-, -CR4R5-, or -OZO-,

Here, R ⁴ and R ⁵ are taken together to form a C _3-10 cycloalkyl or C _5-20 aryl, which is unsubstituted or substituted with C _1-3 straight-chain or branched alkyl or halogen,

이고,Wherein Z is phenylene,

ego,

Wherein X is a single bond, or halogen-substituted or unsubstituted C _1-3 straight-chain or branched alkylene, and

wherein Y is C _1-3 straight-chain or branched alkylene substituted or unsubstituted with halogen).

In the hydrogen gas sensor according to an embodiment of the present invention, the diamine may be at least one selected from the following compound group.

In the hydrogen gas sensor according to an embodiment of the present invention, the diamine is (a) 3,3'-dihydroxy-4,4'-diamino-biphenyl (HAB-OH) and 3,3'-diacetoxy-4, 4'-diamino-biphenyl (HAB-OAc) may be included.

In the hydrogen gas sensor according to an embodiment of the present invention, the polyimide is (a) MDA (4.4'-diaminodiphenyl methane (MDA)), 6F-m-DA (3,4'-hexafluoroisopropylidene-dianiline) and m -TDA (2,4-toluenediamine) one or two diamines selected from the group consisting of, and (b) BCDA (Bicyclo[2,2,2]oct-7-ene-2,3,5,6) - tetracarboxylic dianhydride); can be prepared from a polyamic acid composition containing.

In the hydrogen gas sensor according to an embodiment of the present invention, the polyimide may have an oxygen permeability coefficient of 0.7 to 2 Barrer, a hydrogen/methane gas selectivity of 100 or more, and an oxygen/nitrogen gas selectivity of 5 or more. .

In the hydrogen gas sensor according to an embodiment of the present invention, the polyimide may be a soluble polyimide having solubility in an organic solvent.

In the hydrogen gas sensor according to an embodiment of the present invention, the palladium nanoparticle layer may have a thickness of 1 to 5 nm.

In the hydrogen gas sensor according to an embodiment of the present invention, the surface of the tin oxide layer in the region where the first electrode and the second electrode are spaced apart from each other is the first region where the palladium nanoparticle layer is located, and the palladium nanoparticle layer is located It may include a second region that is not.

In the hydrogen gas sensor according to an embodiment of the present invention, the area of the second region may be 50% to 90% of the total area of the surface of the tin oxide layer partitioned by the first electrode and the second electrode .

In the hydrogen gas sensor according to an embodiment of the present invention, the thickness of the tin oxide layer may be 5 nm to 300 nm.

The hydrogen gas sensor according to the present invention has a fast response speed and high selectivity to hydrogen gas even at room temperature without a separate heating means, and is capable of high-sensitivity sensing even of a low concentration of hydrogen gas.

In addition, the hydrogen gas sensor according to the present invention can have reliability and long-term stability in sensing hydrogen gas by protecting the sensing unit from external environmental factors that may reduce the sensitivity of sensing hydrogen gas.

The method for manufacturing a hydrogen gas sensor according to the present invention has an advantage in that it can easily and economically manufacture a hydrogen gas sensor capable of high-sensitivity hydrogen sensing even at room temperature with a simple and economical process, and thus has very excellent industrial usefulness.

1 is a schematic diagram of a hydrogen gas sensor according to an embodiment of the present invention;
2 is a graph of the detection test result for each hydrogen concentration of the hydrogen gas sensor shown in FIG. 1;
FIG. 3 is a graph of a hydrogen gas selectivity test result of the hydrogen gas sensor shown in FIG. 1 .

Unless otherwise defined in technical terms and scientific terms used in this specification, those of ordinary skill in the art to which this invention belongs have the meanings commonly understood, and in the following description and accompanying drawings, the subject matter of the present invention Descriptions of known functions and configurations that may unnecessarily obscure will be omitted.

Also, the singular form used herein may be intended to include the plural form as well, unless the context specifically dictates otherwise.

In addition, in the present specification, the unit used without special mention is based on the weight, for example, the unit of % or ratio means weight % or weight ratio, and weight % means any one component of the entire composition unless otherwise defined. It means % by weight in the composition.

In addition, the numerical range used herein includes the lower limit and upper limit and all values within the range, increments logically derived from the form and width of the defined range, all values defined therein, and the upper limit of the numerical range defined in different forms. and all possible combinations of lower limits. Unless otherwise defined in the specification of the present invention, values outside the numerical range that may occur due to experimental errors or rounding of values are also included in the defined numerical range.

As used herein, the term 'comprising' is an open-ended description having an equivalent meaning to expressions such as 'comprising', 'containing', 'having' or 'characterized', and elements not listed in addition; Materials or processes are not excluded.

A hydrogen gas sensor according to the present invention includes a tin oxide layer; a first electrode and a second electrode spaced apart from each other on the tin oxide layer; a palladium nanoparticle layer positioned in a region where the first electrode and the second electrode are spaced apart; and a polymer layer positioned on the tin oxide layer and the palladium nanoparticle layer, wherein the polymer layer is a hydrogen-selective polyimide film having a hydrogen permeability coefficient of 10 Barrer or more.

Conventionally, a hydrogen gas sensor uses a sensor using catalytic combustion or a hot wire, SiO2, AlN metal oxide (nitride) semiconductor, and bulk Pd, Pt, SiC, GaN, etc. using a Schottky barrier diode having a bipolar structure. Although sensors using In addition, since it operates at a high temperature of 300°C or higher, it has limitations such as not only high power consumption but also low sensitivity to hydrogen.

As the hydrogen gas sensor according to the present invention includes a polymer layer having a specific hydrogen permeability on the palladium nanoparticle layer and the tin oxide layer serving as a sensing unit to which hydrogen is adsorbed, it is possible to prevent a gas other than hydrogen from reaching the sensing unit. Thus, it exhibits high hydrogen selectivity, and high-sensitivity hydrogen sensing is possible.

In addition, since the hydrogen gas sensor according to the present invention includes a palladium nanoparticle layer in a specific region on the tin oxide layer, the hydrogen gas sensor can quickly and accurately detect even a low concentration of hydrogen gas, and is highly sensitive even when used repeatedly for a long time. can keep Sensing of hydrogen gas is possible even under various temperature and humidity conditions, so the industrial applicability is very high.

1 shows a hydrogen gas sensor according to an embodiment of the present invention.

Referring to Figure 1, the hydrogen gas sensor 1 of the present invention is a substrate; a tin oxide layer 15 positioned on the substrate; a first electrode 21 and a second electrode 23 positioned on the tin oxide layer 15; a palladium nanoparticle layer 30 positioned in a region where the first electrode 21 and the second electrode 23 are spaced apart; and a polymer layer positioned on the tin oxide layer 15 and the palladium nanoparticle layer 30 .

Specifically, the substrate 10 is not particularly limited as long as it is made of an insulating material, and may be glass, ceramic, alumina, a silicon wafer, or a polymer. For example, unlike shown in the drawings, the polymer substrate 10 may be, for example, a flexible polyimide substrate 10 or a flexible polyethylene terephthalate substrate 10 . Such a polymer substrate 10 has flexibility and insulation, and at the same time exhibits light transmittance, and can be applied to various fields.

The tin oxide layer 15 and the palladium nanoparticle layer 30 are sensing units for sensing hydrogen, and hydrogen gas can be sensed by the tin oxide layer 15 and the palladium nanoparticle layer 30 . Specifically, when hydrogen is exposed to the tin oxide layer 15 and the palladium nanoparticle layer 30 in a state in which power is supplied to the first and second electrodes 23, hydrogen is adsorbed and electrical properties are changed to generate hydrogen. can be detected

The tin oxide layer 15 is made of tin oxide (SnO _x ), and depending on the degree of oxidation, O _x may be selected from O ₁ to O ₁₀ , but is not limited thereto. The tin oxide layer 15 has a higher hydrogen adsorption rate relative to the area compared to other oxide layers, so that it is possible to sense even low-concentration hydrogen gas.

The thickness of the tin oxide layer 15 may be 5 to 300 nm, specifically 30 to 200 nm, but is not limited thereto. However, it may exhibit a high hydrogen sensitivity compared to the thickness in the above range.

The palladium nanoparticle layer 30 is positioned in a region where the first electrode 21 and the second electrode 23 on the tin oxide layer 15 are separated from each other, and is dispersed as discrete particles on the tin oxide layer. Palladium nanoparticles may exist as zero-dimensional particles or aggregates of zero-dimensional particles. In an embodiment, the palladium nanoparticles may be composed of aggregates having an average particle diameter of 0.5 to 1 nm. As such a palladium nanoparticle layer has both conductivity and excellent hydrogen adsorption ability, it can adsorb a large amount of hydrogen gas and enables high-sensitivity sensing.

Specifically, the present invention provides hydrogen gas sensing with high sensitivity as the palladium nanoparticle layer is located in a specific region, that is, in a region where the first electrode 21 and the second electrode 23 on the tin oxide layer 15 are spaced apart. It is possible. The palladium nanoparticles are dispersed as discontinuous particles in the region, and preferably, the palladium nanoparticles are a partial region on the surface of the tin oxide layer 15 in the region where the first electrode 21 and the second electrode 23 are spaced apart. The surface of the tin oxide layer 15 in the region where the first electrode 21 and the second electrode 23 are spaced apart from the first region where the palladium nanoparticle layer 30 is located and the palladium nanoparticle layer 30 A second region not located may be included.

The thickness of the palladium nanoparticle layer is not limited as long as hydrogen adsorption is possible, but preferably, the thickness of the palladium nanoparticle layer may be 1 to 5 nm, specifically 2 to 4 nm. In the above range, the second region may be appropriately formed.

In detail, the upper area of the tin oxide layer exposed to the outside without palladium nanoparticles, that is, the area of the second region, is the tin oxide layer partitioned by the first electrode 21 and the second electrode 23 ( 15) 50% to 90%, preferably 60% to 80% of the total area of the surface. The hydrogen gas sensor including the tin oxide layer 15 and the palladium nanoparticle layer 30 as described above is capable of not only high-sensitivity sensing but also hydrogen sensing under various environmental conditions. Specifically, the hydrogen gas sensor is capable of high-sensitivity hydrogen sensing even at a temperature of -50°C to 300°C and a humidity of 10 to 80%.

The first electrode 21 and the second electrode 23 are for measuring a change in current or resistance, and are spaced apart from each other on the tin oxide layer 15 . As an example, copper, aluminum, nickel, titanium, silver, gold, platinum, palladium, etc. may be mentioned, but are not limited thereto, and any material used as a general electrode may be used. Each of the first electrode 21 and the second electrode 23 may have a thickness of 10 nm to 200 nm, specifically, 50 nm to 150 nm, but is not limited thereto.

The polymer layer 50 allows hydrogen gas to selectively permeate to enable more sensitive hydrogen gas sensing. Furthermore, the polymer layer 50 serves to protect the sensing unit, such as preventing the escape of palladium nanoparticles from external environments such as moisture and air, and prevents the hydrogen gas sensitivity from decreasing due to moisture when exposed to the outside for a long time. That is, the polymer layer 50 can significantly improve the sensitivity, hydrogen selectivity, and physical and chemical stability of the sensing unit. When the polymer layer 50 is formed on the tin oxide layer 15 , the tin oxide layer 15 exposed to the outside, ie, the second region, may be in direct contact with the polymer layer 50 . Such a hydrogen gas sensor may further increase hydrogen selectivity.

Preferably, the polymer layer is a hydrogen-selective polyimide film having a hydrogen permeability coefficient of 10 Barrer or more.

Specifically, the polyimide may include (a) at least one diamine represented by the following Chemical Formula 1; And (b) BCDA (Bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride); can be prepared by polymerizing the monomer composition consisting of.

[Formula 1]

(In Formula 1,

,

,

또는

이고,A is

,

,

or

ego,

Here, R ¹ is hydrogen and 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl,

Each of R ² and R ³ is hydrogen, 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl, or adjacent R ² and R ³ are linked together to form a single bond can do,

Wherein B is a single bond, halogen-substituted or unsubstituted C _1-3 linear or branched alkylene, halogen-substituted or unsubstituted C _2-4 alkenylene, -S-, -(S=O )-, -(O=S=O)-, -CR4R5-, or -OZO-,

Here, R ⁴ and R ⁵ are taken together to form a C _3-10 cycloalkyl or C _5-20 aryl, which is unsubstituted or substituted with C _1-3 straight-chain or branched alkyl or halogen,

이고,Wherein Z is phenylene,

ego,

Wherein X is a single bond, or halogen-substituted or unsubstituted C _1-3 straight-chain or branched alkylene, and

wherein Y is C _1-3 straight-chain or branched alkylene substituted or unsubstituted with halogen).

More specifically, the diamine may be at least one selected from the following compound group.

In one aspect of the present invention, the 　 polyimide is, (a) MDA (4.4'-diaminodiphenyl methane (MDA), 6F-m-DA (3,4'-hexafluoroisopropylidene-dianiline) and m-TDA (2,4) -toluenediamine) one or two diamines selected from the group consisting of; and (b) BCDA (Bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride); It may be prepared from a polyamic acid composition comprising the.

In one aspect of the present invention, the polyimide is (a) at least one diamine represented by the following formula (1); and (b) 4,4′-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA); may be prepared by polymerizing a monomer composition consisting of.

[Formula 1]

(In Formula 1,

,

,

또는

이고,A is

,

,

or

ego,

Here, R ¹ is hydrogen and 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl,

Each of R ² and R ³ is hydrogen, 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl, or adjacent R ² and R ³ are linked together to form a single bond can do,

Wherein B is a single bond, halogen-substituted or unsubstituted C _1-3 linear or branched alkylene, halogen-substituted or unsubstituted C _2-4 alkenylene, -S-, -(S=O )-, -(O=S=O)-, -CR4R5-, or -OZO-,

Here, R ⁴ and R ⁵ are taken together to form a C _3-10 cycloalkyl or C _5-20 aryl, which is unsubstituted or substituted with C _1-3 straight-chain or branched alkyl or halogen,

이고,Wherein Z is phenylene,

ego,

Wherein X is a single bond, or halogen-substituted or unsubstituted C _1-3 straight-chain or branched alkylene, and

wherein Y is C _1-3 straight-chain or branched alkylene substituted or unsubstituted with halogen).

Specifically, the diamine is (a) 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB-OH) and 3,3′-diacetoxy-4,4′-diamino-biphenyl (HAB-OAc) may include

In one aspect of the present invention, the polyimide may have an oxygen permeability coefficient of 0.7 to 2 Barrer, a hydrogen/methane gas selectivity of 100 or more, and an oxygen/nitrogen gas selectivity of 5 or more.

In one aspect of the present invention, the polyimide may be a soluble polyimide having solubility in an organic solvent.

The method of detecting hydrogen gas of the present invention through the hydrogen gas sensor of the present invention may be performed by measuring the current or resistance before and after exposing the detection target gas to the sensing unit. In one non-limiting embodiment, measuring a drain current Ids(ref) of a hydrogen gas sensor to set a reference; introducing a detection target gas to a sensing unit positioned between the first and second electrodes; a detection step of measuring a drain current Ids(detect) when a detection target gas is introduced; and analyzing the concentration of the detection gas using the measured drain current value, and the detection gas may be detected based on a drain current value changed (increased) before and after introduction of the detection target gas. Alternatively, it goes without saying that the detection of the detection gas may be performed with a changed resistance value instead of a changed drain current value before and after introduction of the detection target gas.

In this case, the operating (detection) temperature of the hydrogen gas sensor may be in the range of -50 to 300 °C, specifically -10 to 200 °C, and more specifically 4 to 100 °C.

Such a hydrogen gas detection method may detect hydrogen gas having a concentration range of 0.1 to 100000 ppm, specifically, 1 to 80000 ppm.

Hereinafter, a method for manufacturing a hydrogen gas sensor of the present invention will be described in detail.

The method for producing hydrogen gas of the present invention comprises the steps of: a) forming a tin oxide layer on one surface of an insulating layer; b) forming a first electrode and a second electrode spaced apart from each other on one surface of the tin oxide layer not in contact with the insulating layer; and c) forming a palladium nanoparticle layer in a region where the first electrode and the second electrode are spaced apart; and d) forming a polymer layer on the palladium nanoparticle layer. Such a manufacturing method has the advantage of being able to manufacture a hydrogen gas sensor with excellent hydrogen selectivity, that is, the hydrogen gas sensor of the present invention described above, and has an advantage that the process is easy and simple and can be commercialized.

In the present invention, after step a), step b), and step c) may be sequentially performed, but depending on the ease of the process, step a), step c), and step b) may be performed.

In detail, the step of forming a tin oxide layer on one surface of the insulating layer (hereinafter, step a)) may be performed by coating the insulating layer with a precursor solution containing a precursor material of tin oxide. Specifically, the tin oxide precursor material may be of any type as long as it is soluble in the solvent used, and may be used without limiting specific precursors such as chloride-based, acetate-based, and halide. The solvent is 2-methoxyethanol (2-mathoxyethanol), isopropanol (isopropanol), dimethylformamide (dimethylformamide), ethanol (ethanol), methanol (methanol), acetylacetone (acetylacetone) and dimethylamine borane (dimethylamineborane) group may include at least one in The molar concentration of the precursor material in the precursor solution may be 0.01M to 3M, specifically 0.025M to 0.2M, and more specifically 0.05 to 0.15M, but is not limited thereto.

The precursor solution may further include a solution stabilizer used in the art.

In step a), the precursor solution is applied on the substrate having the above-described insulating properties to form a precursor thin film. The precursor solution may be applied by a coating method known in the art, such as spin coating, inkjet printing, dip coating, and the like. Thereafter, heat treatment is performed on the precursor thin film of the substrate to form a tin oxide layer.

The heat treatment may be performed at 200° C. to 500° C., specifically, 280° C. to 400° C., but is not limited thereto, and may be performed by dividing the temperature into first and second order.

In step a), it is possible to easily form a tin oxide layer having a homogeneous surface with only a simple solution process, and it is strongly bound to a polymer layer containing an acrylate-based polymer. It is presumed to contribute to sensing.

Thereafter, the step of forming the first electrode and the second electrode spaced apart from each other on the tin oxide layer (hereinafter, step b) is performed.

Specifically, first, a shadow mask having a first electrode and a second electrode-shaped opening is disposed on the substrate on which the tin oxide layer is formed through step a). The shadow mask is a mask designed so that deposition materials can be selectively deposited through the opening, and an electrode part having a precise shape can be manufactured. As the shadow mask, a metal shadow mask, a polymer shadow mask such as PDMS or PMMA, etc. may be used.

Next, a metal is deposited with an electron beam on the substrate on which the shadow mask is disposed to form a first electrode and a second electrode on the tin oxide layer. The metal may include, but is not limited to, copper, aluminum, nickel, titanium, silver, gold, platinum, and palladium.

Next, a step (hereinafter, step c) of forming a palladium nanoparticle layer in a region where the first electrode and the second electrode are spaced apart is performed.

In step c), the palladium nanoparticle layer may be formed by depositing palladium nanoparticles in the form of clusters and dispersed particles. Deposition of palladium nanoparticles may use a physical or chemical method, preferably sputtering method, thermal evaporation method, electron beam evaporation method, electroplating method, may be deposited in the form of spraying an aqueous metal solution on the sample surface, but is not necessarily limited thereto it is not

In one aspect of the present invention, in step c), the palladium nanoparticle layer may be formed by depositing only a partial region of the surface of the tin oxide layer. Accordingly, the surface of the tin oxide layer in the area where the first electrode and the second electrode are spaced apart can be divided into a first area where the palladium nanoparticle layer is located and a second area exposed to the outside because the palladium nanoparticle layer is not located, It is possible to fabricate a hydrogen gas sensor with even better sensitivity.

In step d), the polymer layer may be formed by coating a liquid polymer resin on the tin oxide layer and the palladium nanoparticle layer. Specifically, the polymer resin is a polyimide resin, and may be applied through spin coating, spray coating, knife coating, or roll coating, but is not limited thereto, and may be coated by various methods known in the art.

Hereinafter, the present application will be described in more detail using examples, but the following examples are only illustrative to aid understanding of the present application, and the content of the present application is not limited to the following examples.

(Example 1)

Spin coating with a 0.1M SnCl ₂ solution using 2-methoxyethanol as a solvent on the washed silicon wafer substrate (thickness: 500-550um, resistivity: <0.005 ohm, SiO ₂ thickness: 3000A (Dry)) (3,000rpm, 60 seconds) ) and then annealed at 300° C. for 1 hour to form a SnO ₂ layer. Then, Al was deposited to a thickness of 90 nm and a width of 1000 μm through a shadow mask to form first and second electrodes. In this case, the separation distance between the first and second electrodes was 200 μm. Then, Pd was deposited at a rate of 0.1 Å/s using a thermal evaporator to have an average thickness of 3 nm to prepare a sensing unit.

For the synthesis of polyimide, BCDA, an alicyclic dianhydride, and MDA, an aromatic diamine (4.4'-diaminodiphenyl methane (MDA)) are put in a round glass flask, and a mechanical stirrer, thermometer, and condenser are installed, and m-cresol is put there. Under nitrogen atmosphere, the equivalent mole of BCDA and diamine were sufficiently dissolved.Then, stirred at 75° C. for 2 hours, and then stirred at 200° C. for 18 hours to obtain a high molecular weight polyimide solution. After each dilution with dimethylforamide (DMF), it was gradually dropped into a beaker containing methanol to precipitate each, and washed with a large amount of methanol to obtain a purified polyimide powder. Mid (BCDA-MDA) was obtained.

After dissolving the polyimide powder in DMF at a concentration of 10 wt%, spin coating (4,000 rpm, 30 seconds) on the sensing unit was performed, and then heat treatment was performed at 175° C. for 10 minutes to prepare a hydrogen gas sensor.

(Comparative Example 1)

In Example 1, a hydrogen gas sensor was manufactured in the same manner as in Example 1, except that the polyimide dissolved in DMF was not coated. The manufactured hydrogen gas sensor is one in which the polymer layer is not finally formed in Example 1.

(Experimental Example 1) Detection test

Gas detection characteristics were measured using a semiconductor parameter analyzer (B15000A, Agilent) of a MSTECH probe station with an MFC system. The hydrogen gas sensor was placed about 1 cm below the gas tube and directly exposed to the gas of the required concentration. The hydrogen gas detection test was conducted at room temperature. H ₂ gas (100 ppm, 1 mol %, 10 mol % in N ₂ ) and dry air were mixed using MFC to produce hydrogen gas at a desired concentration (mol %). The detection characteristic (Response) was expressed through the ratio (I _g /I _a ) of the hydrogen gas sensor current (I _a ) before exposure to hydrogen gas and the hydrogen gas sensor current (I _g ) after hydrogen gas exposure.

2 is a graph showing the results of the detection test (Experimental Example) for each hydrogen concentration of the hydrogen gas sensor manufactured in Example 1 and Comparative Example 1. Referring to FIG. Specifically, Figure 2 shows the detection test results for each concentration of 0.01 to 0.1 mol%.

Referring to FIG. 2 , it was confirmed that Example 1 had higher sensitivity than Comparative Example 1 and that the sensing range was very wide.

3 is a graph showing the hydrogen gas selectivity test result of Example 1 and Comparative Example 1. Specifically, FIG. 3 a) shows 1000 ppm of carbon monoxide (CO), FIG. 3 b) shows 1000 ppm of methane gas (CH ₄ ), and FIG. 3 c) exposes 1000 ppm of hydrogen gas to each hydrogen gas sensor, resulting in a detection test. to be.

Referring to FIG. 3 , it was confirmed that Example 1 had higher selectivity for hydrogen compared to Comparative Example. Example 1 showed little sensitivity to carbon monoxide and methane gas, while high sensitivity to hydrogen gas.

As described above, the present invention has been described with specific matters and limited examples and drawings, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is not limited to the above embodiments. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (12)

tin oxide layer;
a first electrode and a second electrode spaced apart from each other on the tin oxide layer;
a palladium nanoparticle layer positioned in a region where the first electrode and the second electrode are spaced apart; and
A polymer layer positioned on the tin oxide layer and the palladium nanoparticle layer,
The polymer layer is a hydrogen gas sensor, characterized in that the hydrogen permeation coefficient is a hydrogen-selective polyimide film of 10 Barrer or more. According to claim 1,
The polyimide is (a) at least one diamine represented by the following formula (1); And (b) BCDA (Bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride); produced by polymerizing a monomer composition consisting of, a hydrogen gas sensor.
[Formula 1]

(In Formula 1,
A is

,

,

or

ego,
Here, R ¹ is hydrogen and 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl,
Each of R ² and R ³ is hydrogen, 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl, or adjacent R ² and R ³ are linked together to form a single bond can do,
Wherein B is a single bond, halogen-substituted or unsubstituted C _1-3 linear or branched alkylene, halogen-substituted or unsubstituted C _2-4 alkenylene, -S-, -(S=O )-, -(O=S=O)-, -CR4R5-, or -OZO-,
Here, R ⁴ and R ⁵ are taken together to form a C _3-10 cycloalkyl or C _5-20 aryl, which is unsubstituted or substituted with C _1-3 straight-chain or branched alkyl or halogen,
Wherein Z is phenylene,

ego,
Wherein X is a single bond, or halogen-substituted or unsubstituted C _1-3 straight-chain or branched alkylene, and
wherein Y is C _1-3 linear or branched alkylene substituted or unsubstituted with halogen). According to claim 1,
The polyimide is (a) at least one diamine represented by the following formula (1); And (b) 4,4'- (Hexafluoroisopropylidene) diphthalic anhydride (6FDA); produced by polymerizing a monomer composition consisting of, a hydrogen gas sensor.
[Formula 1]

(In Formula 1,
A is

,

,

or

ego,
Here, R ¹ is hydrogen and 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl,
Each of R ² and R ³ is hydrogen, 1 to 4 substituents independently selected from the group consisting of C _1-3 straight-chain or branched alkyl, or adjacent R ² and R ³ are linked together to form a single bond can do,
Wherein B is a single bond, halogen-substituted or unsubstituted C _1-3 linear or branched alkylene, halogen-substituted or unsubstituted C _2-4 alkenylene, -S-, -(S=O )-, -(O=S=O)-, -CR4R5-, or -OZO-,
Here, R ⁴ and R ⁵ are taken together to form a C _3-10 cycloalkyl or C _5-20 aryl, which is unsubstituted or substituted with C _1-3 straight-chain or branched alkyl or halogen,
Wherein Z is phenylene,

ego,
Wherein X is a single bond, or halogen-substituted or unsubstituted C _1-3 straight-chain or branched alkylene, and
wherein Y is C _1-3 straight-chain or branched alkylene substituted or unsubstituted with halogen). 3. The method of claim 2,
The diamine is at least one selected from the following compound group, a hydrogen gas sensor.

4. The method of claim 3,
The diamine comprises (a) 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB-OH) and 3,3′-diacetoxy-4,4′-diamino-biphenyl (HAB-OAc) , hydrogen gas sensor.
3. The method of claim 2,
The polyimide is
(a) one or two selected from the group consisting of MDA (4.4'-diaminodiphenyl methane (MDA), 6F-m-DA (3,4'-hexafluoroisopropylidene-dianiline) and m-TDA (2,4-toluenediamine)) species of diamines; and
(B) BCDA (Bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride); which will be prepared from a polyamic acid composition comprising, a hydrogen gas sensor. According to claim 1,
The polyimide has an oxygen permeability coefficient of 0.7 to 2 Barrer, a hydrogen/methane gas selectivity of 100 or more, and an oxygen/nitrogen gas selectivity of 5 or more, a hydrogen gas sensor
. According to claim 1,
wherein the polyimide is a soluble polyimide having solubility in an organic solvent.
According to claim 1,
The palladium nanoparticle layer has a thickness of 1 to 5 nm, a hydrogen gas sensor.
10. The method of claim 9,
The surface of the tin oxide layer in the area where the first electrode and the second electrode are spaced apart from each other includes a first area in which the palladium nanoparticle layer is located and a second area in which the palladium nanoparticle layer is not located.
11. The method of claim 10,
The area of the second region is 50% to 90% of the total area of the surface of the tin oxide layer partitioned by the first electrode and the second electrode, the hydrogen gas sensor.
According to claim 1,
A hydrogen gas sensor having a thickness of 5 nm to 300 nm of the tin oxide layer.

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