KR101014851B1 - Method for manufacturing gas sensor for detecting mixed gas and the gas sensor manufactured by the method - Google Patents

Abstract

The present invention relates to a method for manufacturing a gas sensor for detecting a mixed gas using a micro-contact printing technology, a gas sensor for detecting a mixed gas produced therefrom and a method for detecting a mixed gas using the gas sensor, more specifically, Forming intaglio patterns on the master mold, respectively; Preparing a plurality of polymer coatings having an embossed pattern corresponding to the intaglio pattern by pouring and curing a liquid polymer on the master mold; Depositing different gas detection materials on surfaces of the plurality of polymer coatings, and sequentially forming a gas detection material pattern on a substrate by using microcontact printing technology; And forming a contact resistance reduction material pattern at an intersection point of the different gas detection material patterns, a method of manufacturing a gas sensor for detecting a mixed gas, a gas sensor manufactured therefrom, and a method of detecting a mixed gas using the gas sensor. To provide.

According to the present invention, various gas detection materials can be easily implemented in a single sensor without requiring expensive equipment compared to a conventional lithography process, enabling accurate cross-junction sensor analysis and low power consumption. It is possible to provide a method for manufacturing a gas sensor for detecting a mixed gas, which enables accurate qualitative and quantitative analysis of the mixed gas with high sensitivity, a gas sensor for detecting a mixed gas prepared therefrom, and a method for detecting a mixed gas using the gas sensor. have.

Gas Sensor, Fine Contact Printing

Description

Method for manufacturing gas sensor for detecting mixed gas and the gas sensor manufactured by the method}

1a to 1c show examples of the planar shape of a master mold according to the invention.

2a to 2c show examples of the polymer coating produced by the master molds according to FIGS. 1a to 1c, respectively.

3 is a schematic illustration of a Lange-Blaze trough.

4A and 4B show schematic process schematic diagrams for the LB method and the LS method, respectively.

5A and 5B schematically illustrate a process of forming a pattern of a gas detection material having a lattice pattern by using the polymer coating according to FIGS. 2A and 2B, respectively.

6A and 6B are diagrams illustrating a gas sensor for detecting a gas mixture, respectively, manufactured by the process illustrated in FIGS. 5A and 5B.

FIG. 7 is a view schematically illustrating a current flow through a main path and an additional path in the gas sensor as shown in FIG. 6A.

FIG. 8 is a circuit diagram schematically illustrating the flow of current through the main path and the flow of current through the additional path when current flows from A1 to B1 in FIG. 7.

FIG. 9 is a circuit diagram schematically illustrating the flow of current through the main path and the flow of current through the additional path when current flows from A1 to B2 in FIG. 7.

<Description of the symbols for the main parts of the drawings>

600, 601: gas detection unit

610, 611: contact resistance reducing unit

620 and 621: electrode section

The present invention relates to a method for manufacturing a gas sensor for detecting a mixed gas, a gas sensor for detecting a mixed gas produced therefrom, and a method for detecting a mixed gas using the gas sensor, and more particularly, compared to a conventional lithography process. Easily implement a variety of gas detection materials in one sensor without the need for equipment, enables accurate cross-junction sensor mechanism analysis, and accurate sensitivity and quantitative analysis of mixed gases with high sensitivity at low power The present invention relates to a method for manufacturing a gas sensor for detecting a mixed gas, a gas sensor for detecting a mixed gas prepared therefrom, and a method for detecting a mixed gas using the gas sensor.

Gas detection technology, environmental monitoring and chemical process control, space business, agriculture, because it is very important like forestry, the school equipment, has been carried out many studies around the world, the detection of that of NO ₂ gas combustion or vehicle exhaust This is important for environmental pollution monitoring, and the detection of ammonia gas is essential for industrial, medical and ecosystem monitoring.

Conventionally, among electrical sensor materials such as semiconducting metal oxides, organic materials, and mixtures with polymers, semiconducting metal oxides are widely used for detecting NO ₂ or ammonia, and semiconducting metal oxides are 200 to 600. The chemical reactivity between the sensor material and the gas to be detected at a high temperature of ℃ may be used as a sensor (Kong et al., Science 2000, 28, 622). Recent research on gas sensors has shown that GE's Global Research Center has commercialized semiconductor-based flame sensors, and NASA has produced semiconductor gas sensors for spacecraft. Maximillian Fleischer of Germany is working on a gas sensor array that grows a semiconductor oxide array and detects individual gases in the gas mixture. In addition, semiconductor materials such as conductive polymers and organic phthalocyanine may be used to detect NO ₂ and ammonia, but it is difficult to be used as a sensor material due to the high resistance of about 10 ¹⁰ Ω.

On the other hand, a study published in 2000 showed that single-walled carbon nanotubes (SWCNT) can be used to detect NO ₂ and ammonia at room temperature. Several ppm of gas could be measured with only a few seconds of gas exposure (Kong et al., Science 2000, 28, 622). In addition, it was believed that this report originated from the one-dimensional nanostructure of SWCNT, and much attention was focused on the study of semiconducting metal oxides such as V ₂ O ₅ , SnO ₂ , and ZnO.

However, there are not many studies on nanowires yet, and even if experiments as gas sensors are conducted on a single nanowire itself or a film study, the patterned metal electrode in the Jet Propulsion Laboratory in the US He is also conducting research on fabricating sensor arrays by growing nanowires using electro-deposition. Although single nanowires show ideal characteristics as gas sensors, there is a problem that mass production is impossible, and studies on films have overcome some of the productivity problems, but have the disadvantage of not utilizing the properties of nanowires themselves. Furthermore, studies on simple sensing mechanisms based on the sensing characteristics of a single gas have been published, but there are no studies on mixed gas. In addition, the sensor patterning research is also a general metal oxide rather than a nanowire research, and the method is also disadvantageous in the production of small quantities of various varieties because the conventional lithography method is adopted. Therefore, there is a limit in expanding the use of sensors through economical sensor production, and there is a limit in gas sensitivity.

On the other hand, in the case of manufacturing the sensor by the conventional lithography method, not only expensive equipment is required, but even using the nanomaterial required for the production of high-sensitivity sensor, it is difficult to make good use of the characteristics of the nanomaterial, and it is difficult to produce small quantities of various kinds and There was a problem of being very complicated. In addition, even when using a method such as spin-coating or dip-coating, the sensor material is laminated on the substrate in the form of a film, which makes it difficult to integrate devices and to produce a uniform film. Had a problem.

As such, when a sensor is manufactured using a single nanowire, the sensor has excellent performance, efficiency, and sensitivity as a sensor, but it is difficult to process and requires expensive equipment and efforts to manufacture a single device.

Therefore, the first task of the present invention does not require expensive equipment compared to the general silicon process, such as lithography method, it is possible to manufacture a variety of gas detection material as a cross-linked gas sensor in an easy way, It is to provide a method of manufacturing a gas sensor for detecting a mixed gas that can produce a multi-class sensor at a low price.

In addition, the second object of the present invention is to easily analyze the mechanism of the cross-junction sensor because the area where the gas to be detected can be adsorbed is constant and the cross-linked form of the homogeneous gas detection material and the heterogeneous detection material is present in one sensor. In addition, the present invention provides a gas sensor for detecting a mixed gas, which can be easily modularized and implements a low power ultra-high sensitivity gas sensor.

Finally, the third technical problem to be achieved by the present invention is to provide a method for detecting a mixed gas capable of accurate qualitative and quantitative analysis of the mixed gas.

The present invention to achieve the first technical problem,

Forming an intaglio pattern on each of the plurality of master molds;

Preparing a plurality of polymer coatings having an embossed pattern corresponding to the intaglio pattern by pouring and curing a liquid polymer on the master mold;

Depositing different gas detection materials on surfaces of the plurality of polymer coatings, and sequentially forming a gas detection material pattern on a substrate by using microcontact printing technology; And

It provides a method for manufacturing a gas sensor for detecting a mixed gas comprising forming a contact resistance reducing material pattern at the intersection of the different gas detection material patterns.

According to an embodiment of the present invention, the intaglio pattern may be a parallel stripe pattern.

According to another embodiment of the present invention, the intaglio pattern may be a cross pattern.

According to another embodiment of the present invention, the polymer may be polydimethylsiloxane (PDMS).

According to another embodiment of the present invention, the mixed gas may be two or more mixed gases selected from the group consisting of NH ₃ , CO, H ₂ and aldehyde.

According to another embodiment of the present invention, the gas detection material may be two or more materials selected from the group consisting of single-walled carbon nanotubes, vanadium oxide nanowires, zinc oxide nanowires, and tin oxide nanowires.

According to another embodiment of the present invention, the gas detection material may further include a conjugated polymer or a surfactant.

According to another embodiment of the present invention, the substrate may be a metal oxide substrate or a flexible polymer substrate.

According to another embodiment of the present invention, the gas detection material pattern may be a grid pattern.

In addition, the line width of the grid pattern may be 100nm to 100㎛, the thickness may be 1nm to 100nm.

According to another embodiment of the present invention, the microcontact printing technique may be performed by the Langmue-Blaze method (LB method) or the Langmuir-Shaeffer method (LS method).

According to another embodiment of the present invention, the contact resistance reducing material may be selected from the group consisting of gold nanoparticles, silver nanoparticles, platinum nanoparticles and palladium nanoparticles.

According to another embodiment of the present invention, the contact resistance reducing material pattern may be a repeating pattern of circles or polygons having a predetermined arrangement.

In addition, the surface area of one circle or polygon may be 10,000 nm ² to 10,000 μm ² , and the thickness may be 2 nm to 100 nm.

According to another embodiment of the present invention, the gas detection material pattern forming step or the contact resistance reducing material pattern forming step is capping in the gas detection material or contact resistance reducing material by heating or ultraviolet irradiation after the pattern forming step. It may further comprise removing the material.

On the other hand, the present invention to achieve the second technical problem,

Provided is a gas sensor for detecting a mixed gas produced by the above method.

According to an embodiment of the present invention, the gas sensor includes two or more gas detection units made of two or more different gas detection materials for adsorbing two or more different gases to be detected; A contact resistance reduction unit formed at an intersection point of the different gas detection materials; And an electrode unit for measuring electrical characteristics before and after the adsorption of the gas to be detected by the gas sensor.

In addition, the surface area of the gas detection unit may be the same.

Finally, the present invention to achieve the third technical problem,

Provided is a method of detecting a mixed gas using the gas sensor.

According to one embodiment of the present invention, the electrical resistance value after the gas adsorption of the gas detection unit may be calculated by the following equation:

R = (R ₀ + f (l) × w)

Where

R is the electrical resistance value after adsorption of the gas to be detected,

R ₀ is the electrical resistance value before adsorption of the gas to be detected,

f is a sensitivity factor function of the gas detection material,

l is the volume of gas to be detected,

w is the surface area of the gas detection unit.

According to another embodiment of the present invention, the gas detection unit is made of a gas detection material having a resistance value a and a gas detection material having a resistance value b, wherein the gas detection materials are arranged in two pairs of parallel stripes pattern perpendicular to each other. When voltage is applied to both ends of the parallel stripe pattern perpendicular to each other, four resistance values measured by the voltage application may be expressed by the following equation:

.

.

Hereinafter, with reference to the accompanying drawings will be described in more detail the present invention.

Method of manufacturing a gas sensor for detecting a mixed gas according to the present invention, forming a pattern of intaglio on each of a plurality of master mold; Preparing a plurality of polymer coatings having an embossed pattern corresponding to the intaglio pattern by pouring and curing a liquid polymer on the master mold; Depositing different gas detection materials on surfaces of the plurality of polymer coatings, and sequentially forming a gas detection material pattern on a substrate by using microcontact printing technology; And forming a contact resistance reducing material pattern at intersections of the different gas detection material patterns.

In the present invention, a plurality of master molds having a predetermined intaglio pattern are first produced. 1A-1C show examples of the planar shape of a master mold. 1A-1B are examples of master molds that can be used to produce a pattern for forming a gas detector in a final gas sensor, and FIG. 1C is a master mold that can be used for manufacturing a pattern for forming a contact resistance reduction in a final gas sensor. Is an example. The portions marked in white in FIGS. 1A-1C are intaglio patterns.

The gas sensor according to the present invention is for qualitatively and quantitatively analyzing each gas to be detected in a mixed gas in which various types of gas to be detected are mixed. Therefore, the master template corresponds to the number of gases to be detected. A plurality of them are produced. The production of the master mold may be performed by forming a pattern by placing a metal mask or the like on a master substrate such as silicon by a conventional method, that is, an optical lithography method or an e-beam lithography method.

The shape of the intaglio pattern formed on the master mold may vary depending on the pattern of the gas detector formed on the resulting gas sensor, but is not limited thereto, and may be a parallel stripe pattern or a cross pattern. As a simplified example, FIG. 1A shows a master mold with a pair of parallel stripe patterns, and FIG. 1B shows a master mold with one cross pattern.

Next, a step of preparing an embossed pattern on the surface of the polymer coating is performed by pouring and curing the liquid polymer on the prepared master mold to correspond to the intaglio pattern formed on the master mold. 2A to 2C illustrate examples of polymer coatings manufactured by master molds having an intaglio pattern as shown in FIGS. 1A to 1C, respectively. 2A to 2C, polymer coatings manufactured by intaglio patterns formed on a master mold have embossed patterns corresponding to the intaglio patterns. In FIG. 2A to FIG. 2C, the blue or purple portion is an embossed pattern, and in FIG. 2A or 2B, an embossed pattern which can be used to manufacture a pattern for forming a gas detector in the final gas sensor is indicated in blue in the drawing. 2C is an embossed pattern (indicated in purple in the figure) that can be used to produce a pattern for forming a contact resistance reduction portion in the final gas sensor.

Polymeric materials usable in the manufacture of polymeric coatings include, but are not limited to, polymeric materials such as polydimethylsiloxane (PDMS).

Subsequently, different gas detection materials are buried on the surfaces of the plurality of polymer coatings manufactured as described above, and then a gas detection material pattern is sequentially formed on the substrate using a microcontact printing technique.

A self-assembled monolayer may be laminated on the substrate so that the gas detection material is easily adsorbed on the substrate, and the gas detection material is adsorbed using the prepared polymer coating thereon.

Microcontact printing is a kind of soft lithography technology recently developed for the manufacture of micro or nanostructures, and it is possible to realize resolutions of less than 100 nm at low cost and is environmentally friendly. In addition, it is a technique that can be easily applied to the patterning of uneven surfaces. In particular, it is useful to fabricate relatively simple, single-layered structures that can be used as devices in sensors and microanalysis systems in MEMS and applied optics. In the microcontact printing technology, a pattern is made or transferred using a master mold and an elastomer coating manufactured by the master mold.

In the present invention, a pattern of a gas detection material is formed on a substrate by using such a microcontact printing technique. As the gas detection material, various kinds of materials may be employed according to the type of mixed gas to be detected. Although not limited thereto, the mixed gas to be detected may be one or more gases selected from the group consisting of NH ₃ , CO, H _2, and aldehyde, and thus the gas detection material may be a single-walled carbon nanotube or vanadium oxide nanowires. It may be two or more materials selected from the group consisting of, zinc oxide nanowires and tin oxide nanowires. The nanowires used as the gas detection material may be pure nanowires, but may further include conjugated polymers or surfactants to improve performance or improve adsorption with the substrate. The number of master molds produced, the number of polymer coatings, and the number of patterned gas detection materials are determined according to the type of gas to be detected.

In addition, a metal oxide substrate such as a conventional SiO ₂ substrate or a flexible polymer substrate such as polycarbonate may be used as the substrate.

In particular, the method of transferring the gas detection material to the polymer coating in the present invention may use a general spin coating method or a drop-casting & blowing method, but it is a Langeze-Blaze method (LB method) or Langen More preferably, it is carried out by the Langmuir-Shaeffer method (LS method), since the gas sensor generates a surface reaction on the surface of the gas detection material, so that the gas detection material is made of multiple layers of film. In the case of lamination in the form, the film of the outermost surface layer reacts with the gas to be detected to change its electrical properties, but the film of the inner layer has a problem that it is difficult to quantitatively analyze when measuring the electrical properties. Therefore, it is desirable to prevent this problem by laminating a single layer of film using the Langeze-Blaze method or the Langeze-Schaefer method.

The Langmue-Blaze method or Langmue-Schaefer method using Langmuir-Blodgett trough (LB trough) is a method of transferring a single layer or a multilayer film from a liquid-gas interface to a solid surface such as a substrate ( KA Blodgett, JACS . 1935 , 57 , 1007), FIG. 3 shows a schematic of a Lange-Blaze trough, in which a dispersion medium, such as water, is placed in the trough and located at the interface between the dispersion medium and air. It is a method of transferring an amphipathic molecular film to a solid surface such as a substrate. The method of using LB troughs is that if a nonvolatile or non-aqueous material is present on the surface of the water, the adhesion between the molecules of the material and the surface of the water is greater than the cohesion between the molecules, according to the theory of diffusion on the surface of the water. The dispersed and dispersed molecules form a monomolecular thin film, which is a method using a principle that can be transferred to a nano-thick thin film on a solid surface such as a substrate. In this case, in order for the molecules to be dispersed on the water surface, the molecules themselves have amphiphilicity, and when the amphiphilic molecules come into contact with the water surface, the hydrophilic portion is submerged in water and the hydrophobic portion is oriented in the opposite direction to the water surface. The amphiphilic molecules should be located only at the interface between air and water.

The LB trough using method includes a Langerie-Blaze method (LB method) or a Langmuir-Shaeffer method depending on whether the immersion direction of the substrate on which the nano thin film is to be formed is perpendicular or horizontal to the liquid-gas interface. (LS method), and Fig. 4A and 4B show schematic process schematic diagrams for the LB method and the LS method, respectively.

For example, when the pattern of the gas detection material is formed by the microcontact printing technique using the polymer coating according to Fig. 2a or 2b, a lattice pattern may be formed, respectively, in Fig. 5a or 5b is shown in Fig. 2a or The process of forming a lattice pattern of gas detection material using the polymer coating according to 2b is schematically illustrated.

Referring to FIG. 5A, one type of gas detection material is embedded in a polymer coating having a pair of parallel stripe patterns prepared in FIG. 2A, and then the pattern is transferred to a substrate by a microcontact printing method, and then the same stripe pattern is obtained. Another gas detection material is buried in another polymer coating, and the pattern is transferred to the substrate by a microcontact printing method. In this case, when the first polymer coating and the second polymer coating are imprinted on the substrate in a direction perpendicular to each other, the gas detection material pattern of the final lattice pattern as shown in FIG. 5A may be manufactured.

Meanwhile, referring to FIG. 5B, one type of gas detection material is buried in the polymer coating having the cross pattern prepared in FIG. 2B, and then the pattern is transferred to the substrate by a microcontact printing method, followed by another polymer having the same cross pattern. After coating another gas detection material on the coating, the pattern is transferred to the substrate by a microcontact printing method. Further, another polymer coating having the same cross pattern is buried with another gas detection material on the substrate. The substrate is transferred to the substrate by a contact printing method. In this case, when the first, second and third polymer coatings transfer gas detection materials by parallel movement on the substrate at predetermined intervals from each other, a gas detection material pattern of the final lattice pattern is prepared as shown in FIG. 5B. You can do it.

5A and 5B, the gas sensor manufactured by the process of FIG. 5A can detect a mixed gas sample in which two gases are mixed, and the gas sensor manufactured by the process of FIG. 5B has three gases. The difference is that detection of mixed gas samples is possible. In the same manner, it is also possible to manufacture a gas sensor for detecting a mixed gas sample in which four or more kinds of gases are mixed.

On the other hand, although not limited thereto, the line width of the grid pattern may be 100nm to 100㎛, the thickness may be 1nm to 100nm.

Finally, by forming a contact resistance reducing material pattern at the intersection of the different gas detection material pattern produced by the above process it is possible to manufacture a gas sensor for detecting the mixed gas according to the present invention.

In the present invention, the contact resistance reducing material pattern not only serves to reduce the contact resistance at the intersection of the gas detection material pattern, but also the polymer coating is not taken in a precisely vertical or parallel direction during the formation of the gas detection material pattern. In the case of slight twisting, it also plays an additional role of maintaining a constant surface area of the gas detection unit to which the gas to be detected is adsorbed. In addition, the pattern of the contact resistance reducing material formed at the outermost part of the pattern, that is, the point where the different gas detection materials do not intersect, is a final result of the gas sensor, in which the electrode part to which an external power source for connecting the resistance measurement voltage is connected is connected. Function

The contact resistance reducing material is not limited thereto, but the contact resistance reducing material may be selected from the group consisting of gold nanoparticles, silver nanoparticles, platinum nanoparticles, and palladium nanoparticles. It may be a rectangular repeating pattern as shown in 5b, but is not limited thereto, and may be a repeating pattern of circles or polygons having a constant arrangement. In addition, the surface area of one circle or polygon of the contact resistance reduction material pattern may be 10,000 nm ² to 10,000 μm ² , and the thickness may be 2 nm to 100 nm.

On the other hand, after the nanowires or nanoparticles are transferred onto the substrate, it is preferable to further perform a step of heating to an appropriate temperature in a vacuum oven or the like to remove the capping material contained in the nanowires or nanoparticles. Preferably, for gold nanoparticles, for example, this can be done by holding at about 170 ° C. for about 2 hours. Removal of the capping material may be performed by ultraviolet irradiation or the like, and when the capping material is removed, the capping material in the metal nanowires or metal nanoparticles is removed and converted into a general metal. It can also act as a site to reduce contact resistance at the junction.

Finally, by forming the conductive wire to be used as the electrode portion in the outermost pattern on the substrate it is possible to manufacture the gas sensor for detecting the mixed gas according to the present invention.

On the other hand, the present invention provides a gas sensor for detecting a mixed gas produced by the above method in order to achieve the second technical problem.

6A and 6B illustrate a gas sensor for detecting a mixed gas produced by the process shown in FIGS. 5A and 5B, respectively. 6A and 6B, the gas sensor for detecting a mixed gas according to the present invention includes two or more gas detection units 600 and 601 made of two or more different gas detection materials for adsorbing two or more different gases to be detected. Contact resistance reducing parts 610 and 611 formed at intersections of different gas detection materials, and electrode parts 620 and 621 for measuring electrical characteristics before and after adsorption of the gas to be detected by the gas sensor. . In addition, the surface areas of the gas detectors 600 and 601 may be the same.

In addition, the present invention provides a method for detecting a mixed gas using the gas sensor in order to achieve the third technical problem.

Since the detection method of the mixed gas according to the present invention employs two or more different gas detection materials, an electrical change occurs when a gas to be detected is adsorbed to each gas detection material, and the electrical change is caused by the electrode portion of the gas sensor. Through an external power source is detected. Therefore, it becomes possible to qualitatively find out whether the gas used as a detection object exists in a specific gas sample.

Meanwhile, the detection method of the mixed gas according to the present invention can also quantitatively analyze the gas to be detected by measuring the electrical change. Hereinafter, as shown in FIG. 6A, two different gas detection materials are used. The quantitative analysis of the configured gas sensor will be described.

Assume that V = IR where the IV characteristic by voltage application is linear, R is different gas detection materials A and B (hereinafter, gas detection material indicated in blue in FIG. 6A as A, gas detection indicated in orange) If it is assumed that the value is changed by the sum of the resistance of the material (B)), then the resistance R = R _A + R _B can be represented.

Further, if the gas detection unit A has a constant surface area, and the gas detection material A can detect the gas x, and the gas detection material B can detect the gas y, the gas x having a volume of l and the gas y having a volume of m are obtained. When mixed injection, the resistance values R _A and R _B after respective gas adsorption of the gas detection materials A and B can be expressed by the following equation:

R _A = (R _A0 + f _A (l) × w)

R _B = (R _B0 + f _B (m) × w)

Where

R _A0 and R _B0 are the electrical resistance values of A and B, respectively, before gas x and gas y are adsorbed,

w is the surface of the gas detection unit,

l and m are the volumes of gases x and y, respectively,

f _A and f _B are functions of sensitivity factors of gas detection materials A and B.

In the above equation, assuming that there is no contact resistance where the gas detection materials A and B meet (by the contact resistance reducing unit), the resistance is expressed in a matrix as shown in Equation 4:

=

=

In the above formula, the difference between the horizontal rows of the matrix is R _A0 + f _A (1) × w, and the difference between the vertical columns is R _B0 + f _B (m) ± × w. Where R _A0 and R _B0 are The measured value is known and w is the designed value. In addition, f _A and f _B are experimentally derived functions, and variables l and m can be obtained from the resulting values.

Of course, in the actual measurement, there is a resistance in each contact, and when the ideal device is manufactured, the contact resistance R _c is put into a matrix and is expressed as Equation 5 below:

However, since the distance between the gas detectors is still the same, the adsorption amounts l and m of the gases x and y can be obtained.

In the above, the case where two kinds of gas detection substances are employed has been described as an example. However, even when three kinds of gas detection substances are employed, the amount of adsorption of three kinds of gases using the 3 × 3 matrix in the same manner as above is used. In addition, even when four or more gas detection materials are employed, the corresponding types of gases can be analyzed quantitatively.

On the other hand, when measuring the resistance by applying the actual voltage, the current flow is not made in only one path, and the current flow is generated in another additional path, and therefore, the reduction of the resistance obtained through this additional path should be considered. FIG. 7 schematically shows the flow of current through the main path and the additional path in the gas sensor as shown in FIG. 6A, where a ₁₁ , a ₁₂ , a ₂₁ and a ₂₂ are defined by adsorbent A. B ₁₁ , b ₁₂ , b ₂₁ and b ₂₂ are the resistance values at the four gas detectors formed by the adsorbent B, and c is the contact resistance reducing unit at the four gas detectors. The resistance values at In order to calculate the total resistance value R ₁₁ when the current flows from A1 to B1 in FIG. 7, the flow of the current through the main path and the flow of the current through the additional path must be considered. 8 is briefly illustrated as FIG. At this time, the total resistance value R ₁₁ is represented by the following Equation 6, and there is no gain of resistance due to the current flowing in the actual additional path.

However, for flowing a current to the B2 from A1 resistance values R _12, if the current flowing through the B1 from A2 from the resistance values R _21, A2 is the current flowing through the B2 when the total resistance value R ₂₂ is flowing in the additional path There is a gain of the resistance by the current, it should be taken into account, for example, in the case of R ₁₂ briefly showing the flow of the current as shown in Figure 9, wherein R ₁₂ is represented by the following equation (7).

In the above expression, a = a ₁₁ = a ₁₂ = a ₂₁ = a ₂₂ and b = b ₁₁ = b ₁₂ = b ₂₁ = b _22, so the above equation is simplified to the following Equation 8,

If the contact resistance is negligibly small at each intersection by the contact resistance reducing unit, Equation 8 may be represented by Equation 9 below.

Similarly, when R ₂₁ and R ₂₂ are represented, the following Equations 10 and 11 are given.

When this is expressed as a matrix, four resistance values are obtained as in Equation 2 below. Therefore, the gas detection unit is composed of a gas detection material having a resistance value a and a gas detection material having a resistance value b, wherein the gas detection materials are arranged in two pairs of mutually perpendicular parallel stripe patterns, and the parallel stripes perpendicular to each other. When voltage is applied to both ends of the pattern, it can be said that the four resistance values measured by the voltage application are represented by the following Equation 2:

<Equation 2>

.

.

Likewise, when three gas detection materials are used, the nine resistance values measured by voltage application can be expressed in a 3 × 3 matrix by similar calculation techniques.

According to the present invention, various gas detection materials can be easily implemented in a single sensor without requiring expensive equipment compared to a conventional lithography process, enabling accurate cross-junction sensor analysis and low power consumption. It is possible to provide a method for manufacturing a gas sensor for detecting a mixed gas, which enables accurate qualitative and quantitative analysis of the mixed gas with high sensitivity, a gas sensor for detecting a mixed gas prepared therefrom, and a method for detecting a mixed gas using the gas sensor. have.

Claims (21)

Forming an intaglio pattern on each of the plurality of master molds; Preparing a plurality of polymer coatings having an embossed pattern corresponding to the intaglio pattern by pouring and curing a liquid polymer on the master mold; Different gas detection materials were deposited on the surfaces of the plurality of polymer coatings, and then sequentially using a microcontact printing technique by a Langeze-Blaze method (LB method) or a Langmuir-Shaeffer method (LS method). Forming a gas detection material pattern on the substrate; And Forming a contact resistance reducing material pattern at an intersection point of the different gas detection material patterns, The gas detection material is a method of manufacturing a gas sensor for a mixed gas detection, characterized in that at least two materials selected from the group consisting of single-wall carbon nanotubes, vanadium oxide nanowires, zinc oxide nanowires and tin oxide nanowires. The method of claim 1, The engraved pattern is a method of manufacturing a gas sensor for detecting a mixed gas, characterized in that the parallel stripe pattern. The method of claim 1, The engraved pattern is a method of manufacturing a gas sensor for detecting a mixed gas, characterized in that the cross pattern. The method of claim 1, The polymer is a method of manufacturing a gas sensor for detecting a mixed gas, characterized in that the polydimethylsiloxane (PDMS). The method of claim 1, The mixed gas is a method of manufacturing a gas sensor for detecting a mixed gas, characterized in that at least two gases selected from the group consisting of NH ₃ , CO, H ₂ and aldehyde. delete The method of claim 1, The gas detecting material further comprises a conjugated polymer (conjugated polymer) or a surfactant, the method of manufacturing a gas sensor for detecting a mixed gas. The method of claim 1, The substrate is a method of manufacturing a gas sensor for detecting a mixed gas, characterized in that the metal oxide substrate or a flexible polymer substrate. The method of claim 1, The gas detection material pattern is a manufacturing method of a gas sensor for detecting a mixed gas, characterized in that the grid pattern. 10. The method of claim 9, The line width of the grid pattern is 100nm to 100㎛, the thickness is a manufacturing method of the gas sensor for detecting the mixed gas, characterized in that 1nm to 100nm. delete The method of claim 1, The contact resistance reducing material is a manufacturing method of a gas sensor for detecting a mixed gas, characterized in that selected from the group consisting of gold nanoparticles, silver nanoparticles, platinum nanoparticles and palladium nanoparticles. The method of claim 1, The contact resistance reducing material pattern is a method of manufacturing a gas sensor for detecting a mixed gas, characterized in that the repeating pattern of a circle or polygon having a predetermined arrangement. The method of claim 13, The circle or polygon one surface area is ² to 10,000nm 10,000㎛ ^2, and the thickness of the method of producing a gas sensor for detecting gas mixture, characterized in that 2nm to 100nm. The method of claim 1, The gas detecting material pattern forming step or the contact resistance reducing material pattern forming step further includes the step of removing the capping material in the gas detecting material or the contact resistance reducing material by heating or ultraviolet irradiation after the pattern forming step. A method of manufacturing a gas sensor for detecting a mixed gas. Gas sensor for detecting the mixed gas produced by claim 1. The method of claim 16, The gas sensor may include two or more gas detectors each including two or more different gas detection materials for adsorbing two or more different detection target gases; A contact resistance reduction unit formed at an intersection point of the different gas detection materials; And And an electrode unit for measuring electrical characteristics before and after the adsorption of the gas to be detected by the gas sensor. The method of claim 17, Gas sensor for detecting a mixed gas, characterized in that the surface area of the gas detection unit the same. Method of detecting a mixed gas using the gas sensor according to claim 16. The method of claim 19, The detection method of the mixed gas, characterized in that the electrical resistance value after the adsorption of the gas to be detected by the gas detector is calculated by the following equation: &Quot; (1) &quot; R = (R ₀ + f (l) × w) Where R is the electrical resistance value after adsorption of the gas to be detected, R ₀ is the electrical resistance value before adsorption of the gas to be detected, f is a sensitivity factor function of the gas detection material, l is the volume of gas to be detected, w is the surface area of the gas detection unit. The method of claim 19, The gas detection unit is formed of a gas detection material having a resistance value a and a gas detection material having a resistance value b, wherein the gas detection materials are arranged in two pairs of parallel stripe patterns perpendicular to each other, and the parallel stripe pattern perpendicular to each other. When a voltage is applied to both ends of, the four resistance values measured by applying the voltage are expressed by the following equation: <Equation 2>

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