KR20200024504A - Room temperature operable gas sensor using hollow nanofibers and fabrication method thereof - Google Patents

Abstract

The present invention relates to a room temperature operable gas sensor including a hollow nanostructure, which has improved sensitivity, and a manufacturing method thereof. More specifically, the room temperature operable gas sensor comprises: a plurality of electrode frames arranged in parallel with each other to be separated from each other; and a sensing unit including a plurality of free-standing nanowire structures which are arranged between the plurality of electrode frames and electrically connect the plurality of electrode frames. The free-standing nanowire structures are hollow.

Description

Room temperature driven gas sensor using hollow nanostructures and its manufacturing method {ROOM TEMPERATURE OPERABLE GAS SENSOR USING HOLLOW NANOFIBERS AND FABRICATION METHOD THEREOF}

The present invention relates to a room temperature driven gas sensor using a hollow nanostructure and a method of manufacturing the same.

Gas sensors that detect toxic gases, explosive gases, and environmentally harmful gases are becoming increasingly important in many related industries, such as healthcare, defense, terrorism and the environment. At present, research on such a gas sensor is continuously conducted, and in particular, the interest of a semiconductor gas sensor using a metal oxide thin film as a gas sensitive material is increasing.

Most gas sensors operate at high temperatures of ~ 300 ° C because gas molecules do not react to the sensing material at room temperature (RT) due to their low activation energy. In order to operate the gas sensor at high temperature, a complex and high manufacturing cost is required, such as a heater embedded in a circuit, and a process must be added. This increase in power consumption due to high temperature operation causes frequent battery replacement, making application and IoT applications difficult.

Several types of gas sensors that have been recently studied at room temperature (RT) have been developed based on transition metal dichalcogenides (TPDs), graphene and carbon nanotubes (CNTs), but their practical application is poor gas selectivity. Due to fundamental problems such as short lifespan, slow recovery characteristics, difficulty in making large devices, and unreliable recovery behavior, there are limitations to commercialization.

The present invention is to provide a room temperature driving type gas sensor capable of driving at room temperature and improved sensitivity by applying the hollow self-supporting nanowire structure to the gas sensor.

The present invention provides a method for manufacturing a room temperature driving type gas sensor according to the present invention.

The problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

According to one embodiment of the present invention, a plurality of electrode frames disposed parallel and spaced apart from each other; A sensing unit arranged between the plurality of electrode frames at predetermined intervals and including a plurality of free-standing nanowire structures electrically connecting the plurality of electrode frames; It includes, the self-supporting nanowire structure, which is hollow, relates to a room temperature driven gas sensor.

According to an embodiment of the present invention, the support may further include a support for supporting the electrode frame, and the support may include one or more insulating materials selected from the group consisting of glass, silicon, sapphire, and a transparent polymer.

According to one embodiment of the present invention, the support is a plurality, and is formed to be perpendicular to the extending direction of the electrode frame spaced apart in parallel to each other, the electrode frame is seated on the support to contact the plurality of support It may be formed extending outward.

According to one embodiment of the invention, the electrode frame, silver (Ag), copper (Cu), gold (Au), chromium (Cr), aluminum (Al), tungsten (W), zinc (Zn), nickel (Ni), iron (Fe), platinum (Pt), lead (Pb), magnesium (Mg), titanium (Ti), molybdenum (Mo), cobalt (Co), indium tin oxide (ITO), indium zinc oxide ( IZO), Indium Zinc Tin Oxide (IZTO), Aluminum Zinc Oxide (AZO), Gallium Zinc Oxide (GZO), Florin Tin Oxide (FTO), Indium Tin Oxide-Silver-Indium Tin Oxide (ITO-Ag-ITO), Indium Zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc tin oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO) and aluminum zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO) It may be to include at least one selected from the group consisting of.

According to one embodiment of the present invention, the self-supporting nanowire structure may include the same or different electrode material as the electrode frame.

According to one embodiment of the invention, the self-supporting nanowire structure may have an outer diameter of 1 nm to 500 nm and an inner diameter of 1 nm to 500 nm, the outer diameter to inner diameter of 1: 1 to 1: 100 It may have a diameter ratio.

According to one embodiment of the invention, the self-supporting nanowire structure, the inner layer comprising a first metal oxide; And it may have a double layer comprising an outer layer comprising a second silicon oxide.

According to one embodiment of the present invention, the self-supporting nanowire structure may be arranged in a line, a lattice pattern or a random form.

According to one embodiment of the invention, the self-supporting nanowire structure may be arranged to be spaced apart from each other.

According to one embodiment of the invention, the room temperature driven gas sensor, sulfur dioxide (SO ₂ ), ammonia (NH ₃ ), formaldehyde (HCHO), chlorine (Cl ₂ ), hydrofluoric acid (HF), hydrazine (N ₂ H ₄ ), methylamine (CH ₃ NH ₂ ), strong acid (HCl) and trimethylamine ((CH ₃ ) ₃ N), and nitrogen dioxide (NO ₂ ).

According to one embodiment of the invention, the step of contacting the analysis object and the room temperature driven gas sensor according to the present invention; And detecting and analyzing the signal; It relates to a gas detection method using a room temperature driven gas sensor.

According to one embodiment of the invention, preparing a plurality of electrode frames arranged in parallel and spaced apart from each other; Spinning a spinning solution between the plurality of electrode frames to arrange polymer fibers; Coating the polymer fibers with an electrode material to form an electrode material-polymer fiber composite; And heat treating the electrode material-polymer fiber composite to remove at least a portion of the polymer fibers. It relates to a method of manufacturing a room temperature driven gas sensor.

According to one embodiment of the invention, the step of forming the electrode material-polymer fiber composite may be to deposit the electrode material.

According to one embodiment of the invention, the spinning solution comprises a polymer material, or a polymer material and a metal oxide, the polymer material, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethyl Ethylene oxide (PEO), carboxymethyl cellulose (CMC), starch, polyacrylic acid (PA), hyaluronic acid, polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinyl At least one of acetate (PVAc) and PVC (polyvinyl chloride), the metal oxide is silver (Ag), copper (Cu), gold (Au), chromium (Cr), aluminum (Al), tungsten ( At least one of W), zinc (Zn), nickel (Ni), iron (Fe), platinum (Pt), lead (Pb), magnesium (Mg), titanium (Ti), molybdenum (Mo), and cobalt (Co) It may be to include at least one selected from the group consisting of an oxide containing.

According to one embodiment of the invention, the step of arranging the polymer fibers, may be to electrospun the polymer fibers perpendicular to the extending direction of the plurality of electrode frames.

According to one embodiment of the invention, the step of removing the polymer fibers, may be a heat treatment at a temperature of 200 ℃ or more.

The present invention can be driven at room temperature, by applying a high-sensitivity hollow nanostructure to solve the problems caused by the increase in power consumption according to the existing high-temperature operation, it is possible to provide a room temperature driven gas sensor with improved performance of the sensor. have.

The present invention, by applying the hollow nanostructure to the gas sensor in a self-supporting form, it is possible to provide a room temperature driving type gas sensor having an excellent detection performance at a low gas concentration by maximizing the collision frequency with the gas to be detected.

The present invention can provide a room temperature driving type gas sensor which has high selectivity for an analysis target gas and can provide excellent performance stably for a long time.

The present invention, by applying a semiconductor metal oxide-based gas sensor can reduce the manufacturing cost, can provide a room temperature driven gas sensor having a long life and high sensitivity, the gas sensor is a wearable gas sensor that can be applied to various applications and IoT It can be prepared as.

1 exemplarily shows a configuration of a room temperature driving type gas sensor according to the present invention according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing a room temperature driving type gas sensor according to the present invention according to an embodiment of the present invention.
FIG. 3 shows hollow and non-holed fibers at (a) 300K, (b) 450K and (c) 600K, respectively, (d) the outside of the hollow fiber and in accordance with one embodiment of the present invention. Collision frequency versus temperature graph for the inner surface, (e) FDTD simulation (Simulated collision frequency data) for the interaction between the outer surface of the non-porous fiber and the inner and outer surfaces of the hollow fiber and gas molecules will be.
Figure 4 shows, by way of example, a process of the method for manufacturing a room temperature driving type gas sensor according to the present invention according to an embodiment of the present invention.
Figure 5 shows the (a) SEM image, (b) XRD pattern and (c) TEM image of the hollow self-supporting AZO nanowire structure prepared in the embodiment of the present invention. The relevant SAED pattern was inserted inside the image and the optical image of the associated gas sensor was inserted.
FIG. 6 is a gas response curve of (a) self-hollow self-supporting AZO nanofiber gas sensor versus operating temperature for a 0.5 ppm NO ₂ gas in relation to the gas sensor manufactured in the embodiment of the present invention, (b) For 0.5 ppm NO ₂ gas at 50 ° C and room temperature Trends in the response and recovery of sensing of self-supporting self-supporting AZO nanofibers, (c) gas reaction curves of hollow self-supporting AZO nanofibers at various NO ₂ concentrations (0.5-10 ppm) at 250 ° C., and ( d) Gas response curves of hollow self-supporting AZO nanofibers at 0.5 ppm NO ₂ concentration at 250 ° C.
FIG. 7 shows (a) gas selectivity curves of hollow self-supporting AZO nanofibers for different gases having different concentrations at 250 ° C., according to embodiments of the invention, (b) different relative humidity conditions at RT ( 10-75%) gas reaction curves of hollow self-supporting AZO nanofibers with 0.5 ppm NO ₂ gas and (c) hollow self-supporting AZO nanofibers for 0.5 ppm NO ₂ gas up to 30 cycles at RT. Cycle stability curve and (d) gas reaction retention characteristics for 0.5 ppm NO ₂ for 60 days at RT.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms used in the present specification are terms used to properly express preferred embodiments of the present invention, which may vary according to a user, an operator's intention, or customs in the field to which the present invention belongs. Therefore, the definitions of the terms should be made based on the contents throughout the specification. Like reference numerals in the drawings denote like elements.

Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, except to exclude other components unless specifically stated otherwise.

The present invention relates to a room temperature driven gas sensor including a free-standing nanowire structure, and according to an embodiment of the present invention, a hollow nanowire structure is applied to a gas sensor as a self-supporting type. Therefore, it is possible to detect harmful gases at room temperature, and the sensitivity of the sensor can be significantly improved.

The room temperature driven gas sensor according to the present invention will be described with reference to FIG. 1, and FIG. 1 exemplarily shows the configuration of the room temperature driven gas sensor according to the present invention. The room temperature driven gas sensor in Figure 1, the support frame 110; Electrode frame 120; And a sensing unit 130.

The support 110 may support the electrode frame or at least a portion of the electrode may be formed. The support 110 may be provided in plurality, and may be perpendicular to the extending direction of the electrode frame 120, and may be spaced apart in parallel to each other. Alternatively, the support 100 may be an open frame, and may have a circular, elliptical or polygonal shape. The height of the support 110 can be adjusted to enable proper attachment and compatibility to various devices.

The support 110 may be in the form of a film, sheet, thin film, plate, or the like.

The support 110 may include a transparent material and may include, for example, a transparent insulating material such as a metal, an oxide, or a polymer resin. More specifically, glass; silicon; Sapphire; It contains at least one selected from the group consisting of polyimide, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polycarbonate and polyvinyl alcohol transparent polymer, flexible by controlling the curing, components, etc. of the polymer resin It can exhibit transparent properties.

The support 110 may further include a conductive metal layer on at least a portion of the top, and for example, (Ag), copper (Cu), gold (Au), chromium (Cr), aluminum (Al), tungsten ( W), zinc (Zn), nickel (Ni), iron (Fe), platinum (Pt) and lead (Pb) may include one or more selected from the group consisting of. The conductive metal layer is 1 nm or more; 1 nm to 1000 nm; Or 1 nm to 10 μm thick.

The electrode frame 120 may be formed on the upper part of the support 110 to extend outside the portion contacting the plurality of the support 110. The electrode frame 120 may be a plurality of parallel and spaced apart from each other. The electrode frame 120 may include an electrode material and may be made of the electrode material itself, or may include a deposition layer, a coating layer, or a plating layer of the electrode material, or a film, a sheet, or the like.

The electrode material may include a metal, a metal oxide, or the like, and for example, silver (Ag), copper (Cu), gold (Au), chromium (Cr), aluminum (Al), tungsten (W), Zinc (Zn), Nickel (Ni), Iron (Fe), Platinum (Pt), Lead (Pb), Magnesium (Mg), Titanium (Ti), Molybdenum (Mo), Cobalt (Co), Indium Tin Oxide (ITO) ), Indium zinc oxide (IZO), Indium zinc tin oxide (IZTO), Aluminum zinc oxide (AZO), Gallium zinc oxide (GZO), Florin tin oxide (FTO), Indium tin oxide-Silver-Indium tin oxide (ITO- Ag-ITO), indium zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc tin oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO) and aluminum zinc oxide-silver-aluminum zinc oxide It may include at least one selected from the group consisting of (AZO-Ag-AZO). The electrode material may include various shapes such as nanotubes, nanowires, nanorods, nanoneedles, nanoparticles, and the like.

The electrode frame 120 may be a transparent electrode and includes 1 nm or more; 1 nm to 1000 nm; When formed to a thickness of 10 nm to 500 μm or 10 nm to 10 mm, and included within the thickness range, it is possible to stably seat the self-supporting nanowire structure and to improve the sensitivity of the sensor.

The sensing unit 130 includes a plurality of free-standing nanowire structures as active materials for gas detection, wherein the nanowire structures are hollow structures and are arranged in parallel with each other. May be disposed between 120. That is, since both ends of the nanowire structure are disposed in contact with each other on the electrode frames 120 parallel to each other, the electrode frames 120 may be electrically connected to each other, and open areas between the electrode frames 120 parallel to each other. In addition to exposing the self-supporting nanowire structure, the gas contact and collision, and the detectable area of the self-supporting nanostructure by the hollow structure is increased to improve the sensitivity and performance of the gas sensor at room temperature.

This will be described in detail with reference to FIG. 3. Figure 3 is, in accordance with an embodiment of the invention illustrates the FDTD simulation of the contact frequency of the NO ₂ gas of the hollow nano structure, referring to Fig. 3, NO ₂ gas is the contact frequency in the interior of the hollow nanostructures Large, which may contribute to sensitivity improvement at room temperature.

The free-standing nanowire structure may be configured to adjust the number density of the gas sensor according to the arrangement interval, the diameter of the nanowire structure, the number of nanowire structures, and the like when arranged between the electrode frames 120. Transparency and electrical properties can be improved. For example, the plurality of self-supporting nanowire structures may be arranged in a line, lattice form or random shape. It may also be arranged spaced apart from each other at predetermined intervals. By controlling the number density, it is possible to prevent a decrease in transparency due to an increase in the number of nanowire structures, and to prevent a decrease in electrical characteristics due to an increase in electrical resistance.

The self-supporting nanowire structure may have an outer diameter of 1 nm to 500 nm and an inner diameter (medium diameter) of 1 nm to 500 nm, and an outer diameter to an inner diameter may have a diameter ratio of 1: 1 to 1: 100. have. If it is within the above range, there is a restriction on the inflow of gas into the hollow when the outer diameter is larger than the inner diameter, and the difficulty and sensitivity of the room temperature driving of the gas sensor is lowered due to the reduction of the contact and collision area of the gas on the inner surface. Can be prevented.

 The self-supporting nanowire structure may be porous, at least 10% of the total area of the structure; 30%; Or 50% or more.

In the self-supporting nanowire structure, the hollow structure may consist of a single or multiple layers of shells. The plurality of layers of shells may comprise the same or different materials. For example, the plurality of shells may be composed of a double layer consisting of an inner layer comprising a first material and an outer layer consisting of a second material. In addition, the inner layer may exhibit higher porosity than the outer layer due to the removal of the polymer during the firing process. The first material and the second material may be the same or different.

The self-supporting nanowire structure may include a transparent electrode material that is the same as or different from that of the transparent electrode, and may include, for example, a metal, a metal oxide, and more specifically, silver (Ag), Copper (Cu), Gold (Au), Chromium (Cr), Aluminum (Al), Tungsten (W), Cobalt (Co), Zinc (Zn), Nickel (Ni), Iron (Fe), Platinum (Pt), Lead (Pb), ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , NiO, TiO ₂ , CuO, In ₂ O ₃ , Zn ₂ SnO ₄ , Co ₃ O ₄ , PdO, LaCoO ₃ , NiCo ₂ O ₄ , V ₂ O ₅ , RuO ₂ , IrO ₂ , MnO ₂ , InTaO ₄ , InTaO ₄ , Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Indium Zinc Tin Oxide (IZTO), Aluminum Zinc Oxide (AZO), Gallium Zinc Oxide (GZO), Florin Tin Oxide (FTO), Indium Tin Oxide-Silver-Indium Tin Oxide (ITO-Ag-ITO), Indium Zinc Oxide-Silver-Indium Zinc Oxide (IZO-Ag-IZO) ), Indium zinc tin oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO) and aluminum zinc oxide-silver-al Minyum from the group consisting of zinc oxide (AZO-AZO-Ag) it may be one containing at least one selected. The electrode material may include various shapes such as nanotubes, nanowires, nanorods, nanoneedles, nanoparticles, and the like.

According to one embodiment of the invention, the room temperature driven gas sensor, 75% or more for light in the wavelength range of 300 nm to 1000 nm; At least 80%; Transmittance of greater than or equal to 85%.

According to an embodiment of the present invention, the room temperature driven gas sensor may exhibit high selectivity and high sensitivity for a sensing object at a temperature of room temperature or room temperature to 100 ° C. and a low concentration of gas at a concentration of 0.5 ppm or less.

According to one embodiment of the invention, the room temperature driven gas sensor, as shown in Figure 1, may further include a configuration for gas detection and driving, and be assembled with a variety of substrate, case 150, etc. Can be. For example, the driving unit 140 for supplying current, an analysis unit (not shown) for detecting a current signal, and an inlet and an outlet through which analytical sample is injected and discharged may be included. Can be applied.

According to one embodiment of the invention, the room temperature driven gas sensor is for detecting harmful gases, for example, sulfur dioxide (SO ₂ ), ammonia (NH ₃ ), formaldehyde (HCHO), chlorine (Cl ₂ ), at least one of hydrofluoric acid (HF), hydrazine (N ₂ H ₄ ), methylamine (CH ₃ NH ₂ ), strong acid (HCl) and trimethylamine ((CH ₃ ) ₃ N), and nitrogen dioxide (NO ₂ ) Sense, and may preferably be nitrogen dioxide (NO ₂ ).

According to the present invention, the room temperature driving type gas sense according to the present invention may be attached to various substrates and products such as transparent electronic products, windows, windows, etc. to provide a function of a gas sensor. For example, the transparent electronic product may be a transparent display, a transparent solar cell, a transparent mobile phone, a smart watch, or the like. For example, it is possible to reduce the power consumption by the room temperature driving and to reduce the battery consumption, it can be applied to IoT sensors and wearable devices.

The present invention relates to a gas sensing method using a room temperature driven gas sensor according to the present invention. According to an embodiment of the present invention, the method comprises contacting a room temperature driven gas sensor and an analyte; And detecting and analyzing the signal. In the gas sensing method, a quantitative and qualitative analysis of a desired gas may be performed by using an electrical signal such as an electrical resistance change. The sensing object is as mentioned above.

The present invention relates to a method for manufacturing a transparent gas sensor according to the present invention. According to one embodiment of the present invention, the method includes preparing a support (210); Forming an electrode frame (220); Arranging 230 the polymer fibers; Forming an electrode material-polymer fiber composite (240); And removing the polymer fiber by heat treatment (250).

The step 220 of preparing the support is to prepare the above-mentioned support frame according to the use of the sensor.

Forming the electrode frame 230 is a step of forming a plurality of electrode frames that are seated on the top of the support, arranged in parallel and spaced apart from each other. It may be formed by seating in the form of an electrode frame or by attaching an electrode sheet, a film, a thin film, or the like on a base of the frame, or coating or depositing on the base. The coating may use at least one selected from the group consisting of dip coating, spin coating, roll coating, bar coating, and spray coating.

The deposition is sputtering, pulsed laser deposition (PLD), thermal evaporation (Thermal Evaporation), electron beam evaporation (E-beam Evaporation), chemical vapor deposition (Chemical Vapor Deposition), atomic layer deposition (Atomic Layer) Deposition), at least one selected from the group consisting of Inductively Coupled Plasma-Chemical Vapor Deposition and Plasma Enhanced Chemical Vapor Deposition may be used. The deposition may be carried out at a temperature above room temperature.

Arranging 230 the polymer fibers, spinning the polymer fibers to arrange the polymer fibers arranged between the plurality of electrode frames. Arranging the polymer fibers, using a spinning solution comprising a melt of a polymer resin or a polymer resin and a solvent, the spinning solution may further include an electrode material and / or a precursor of the electrode material. For example, the first spinning solution including the polymer resin and the solvent and the second spinning solution including the polymer resin, the electrode material and / or the precursor and the solvent of the electrode material may be spun simultaneously or alternately.

The electrode material is, as mentioned above, 0.1 nm or more; 1 nm or more; 10 nm or more; 300 nm or more; It has a particle size of 500 nm or more (or diameter, length or thickness depending on shape), nanotubes, nanowires, nanorods, nanoneedles, nanoparticles, etc. It may have a form. The precursor may be a metal oxide, acetate, carbonyl, metal carbonate, nitrate, sulfate, phosphate, and chloride to form the electrode material. ) And the like.

The polymer material may be polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene oxide (PEO), carboxymethyl cellulose (CMC), starch, polyacrylic acid (PA), hyaluronic acid ( Hyaluronic acid), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylacetate (PVAc) and PVC (polyvinylchloride), polyethylene terephthalate (PET), polyethylene sulfone (PES), polyethylene Phthalate (PEN), Polycarbonate (PC), Polyimide (PI), Ethylene Vinyl Acetate (EVA), Amorphous Polyethylene Terephthalate (APET), Polypropylene Terephthalate (PPT), Polyethylene Terephthalate Glycerol (PETG), Poly Cyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), cyclopentadiene polymer (CPD) , Polyarylate (PAR), polyetherimide (PEI), polydimethylsiloncene (PDMS), silicone resin, fluorine resin and modified epoxy resin may include at least one selected from the group consisting of.

The polymer resin and / or the electrode material and the precursor thereof, 0.01 parts by weight or more based on 100 parts by weight of the spinning solution; 0.1 parts by weight to 60 parts by weight; Or 1 part by weight to 90 parts by weight.

The solvent may be dissolved and / or dispersed of a polymer resin; And dissolving and / or dispersing the electrode material and / or precursor to produce a spinning solution, for example, water, methanol, ethanol, propanol, isopropanol, 1-methoxy-2-propanol, 1-methoxy -2-propyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methoxy propyl acetate, ethyl lactate, ethyl acetate, acetonitrile, tetrahydrofuran, dimethylformamide, chloroform, toluene, and the like, but are not limited thereto. . In addition, the spinning solution may further include a dispersant if necessary.

Arranging polymer fibers 230 may include electrospinning, melt spinning, electro-blowing, melt-blowing (compound spinning, split yarn), spun At least one selected from the group consisting of a spun-bonded, air laid and wet laid method may be used, and preferably may be electrospinning. The electrospinning can control the thickness of the fiber being spun by varying the size of the electric field and the concentration of the spinning solution.

After the step 230 of arranging the polymer fibers may further comprise the step of drying, at least one minute at room temperature to 200 ℃; It may be dried for 1 to 20 hours.

Forming an electrode material-polymer fiber composite 230 is coating the polymer fiber with an electrode material to form an electrode material-polymer fiber composite. The electrode material may be coated on the surface of the polymer fiber to form a coating layer having a predetermined thickness.

In step 230 of forming the electrode material-polymer fiber composite, a coating method, a deposition method, or both may be used, and preferably, a deposition method may be used.

The step 240 of removing the polymer fibers by heat treatment may include removing at least a portion of the polymer fibers by heat treating the electrode material-polymer fiber composite. That is, the polymer fiber is applied as a template for forming the hollow nanowire structure, 90% or more; Or the whole can be removed. The polymer fibers may be removed to form hollow self-supporting nanofiber structures. The self-supporting nanofiber structures may be arranged across electrode frames arranged in parallel to each other, to provide electrical connection of the electrodes and excellent sensing of gas. For example, the outer layer (or surface layer) of the self-supporting nanofiber structure may be made of an electrode material, and the inner layer surrounding the hollow may have higher porosity because pores are developed than the outer layer.

Heat treatment step 240 of removing the polymer fibers is carried out in an atmosphere of at least one of air, oxygen and inert gas, 200 ℃ or more; 300 ° C. or higher; Or at 400 to 1000 ° C. More than 10 minutes; At least 30 minutes; At least 1 hour; Or 1 hour to 20 hours.

Example

As shown in the process of Figure 2, the electrospinning solution (PVP (1.6g) and Propanol (25ml)) on a copper electrode frame was prepared by stirring at 750 rpm for 1 hour at 40 ℃, then electrospinning (Electrospinning 9.5 kV, Feeding rate = 0.8ml / h, distance 15 cm, 26-gauge needle) to spin the nanofibers. Sputtering deposition of AZO (AZO (2 wt%, 99.999% pure), 50 W RF power, distance 15 cm, 5 mTorr working pressure, RT.) On the spun nanofibers to form a coating layer, put into a tube 400 ℃ Heat treatment for 1 hour at to remove the polymer to prepare a gas sensor.

SEM images, XRD patterns, and TEM images of the hollow AZO nanofibers prepared above were measured and shown in FIG. 5. In FIG. 5, it can be seen that the hollow nanostructure having the AZO shell is formed.

The electrical and sensing characteristics of the manufactured gas sensor were evaluated and shown in FIG. 6. In (a) of FIG. 6, the hollow oxide structure-based sensor shows resistance change even at a low concentration of NO ₂ of 0.5 ppm, and it can be confirmed that a low concentration of NO ₂ is surely detected even at a driving temperature of 50 ° C. .

Selectivity and sensor response characteristics of the manufactured gas sensor were evaluated and shown in FIG. 7. Referring to FIG. 7, the gas sensor has a weak response (Ra / Rg <2.7) to other gases (CO, H ₂ ), but has a significantly higher gas response (Rg / Ra to 13) for NO ₂ gas. High selectivity for NO ₂ . The sensor response is reduced by only 3% at 75% RH, which means that it can operate in the real world without any problems, and shows stable gas response over 30 cycles, and the sensitivity of the sensor is constant sensor signal (96.3% for 60 days). Change) to confirm that the sensor has long-term stability.

 Although the embodiments have been described with reference to the accompanying drawings, those skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even by substitution or replacement by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the following claims.

Claims (15)

A plurality of electrode frames arranged in parallel and spaced apart from each other;
A detector including a plurality of free-standing nanowire structures arranged between the plurality of electrode frames at predetermined intervals and electrically connecting the plurality of electrode frames;
Including,
The self-supporting nanowire structure is hollow,
Room temperature driven gas sensor.
The method of claim 1,
Further comprising a support for supporting the electrode frame,
The support includes one or more insulating materials selected from the group consisting of glass, silicon, sapphire and transparent polymers,
Room temperature driven gas sensor.
The method of claim 2,
The support is a plurality of, is formed to be perpendicular to the extending direction of the electrode frame spaced apart in parallel to each other,
The electrode frame is seated on the upper support is formed to extend outside the portion in contact with the plurality of supports,
Room temperature driven gas sensor.
The method of claim 1,
The electrode frame includes silver (Ag), copper (Cu), gold (Au), chromium (Cr), aluminum (Al), tungsten (W), zinc (Zn), nickel (Ni), iron (Fe), Platinum (Pt), Lead (Pb), Magnesium (Mg), Titanium (Ti), Molybdenum (Mo), Cobalt (Co), Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Indium Zinc Tin Oxide (IZTO) ), Aluminum zinc oxide (AZO), gallium zinc oxide (GZO), florin tin oxide (FTO), indium tin oxide-silver-indium tin oxide (ITO-Ag-ITO), indium zinc oxide-silver-indium zinc oxide ( IZO-Ag-IZO), indium zinc tin oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO) and aluminum zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO) To include,
Room temperature driven gas sensor.
The method of claim 1,
The self-supporting nanowire structure, the electrode frame comprises the same or different electrode material,
Room temperature driven gas sensor.
The method of claim 1,
The self-supporting nanowire structure includes an inner layer including a first metal oxide; And a double layer comprising an outer layer comprising a second gold oxide,
Room temperature driven gas sensor.
The method of claim 1,
The self-supporting nanowire structure is arranged in a line, lattice pattern or random form,
Room temperature driven gas sensor.
The method of claim 1,
The self-supporting nanowire structure is to be spaced apart from each other,
Room temperature driven gas sensor.
The method of claim 1,
The room temperature driven gas sensor is sulfur dioxide (SO ₂ ), ammonia (NH ₃ ), formaldehyde (HCHO), chlorine (Cl ₂ ), hydrofluoric acid (HF), hydrazine (N ₂ H ₄ ), methylamine (CH ₃ NH ₂ ), strong acid (HCl) and trimethylamine ((CH ₃ ) ₃ N) and at least one of nitrogen dioxide (NO ₂ ),
Room temperature driven gas sensor.
Contacting the analysis object with a room temperature driven gas sensor of claim 1; And
Detecting and analyzing the signal;
Containing,
Gas detection method using room temperature driven gas sensor.
Preparing a plurality of electrode frames arranged in parallel and spaced apart from each other;
Spinning a spinning solution between the plurality of electrode frames to arrange polymer fibers;
Coating the polymer fibers with an electrode material to form an electrode material-polymer fiber composite; And
Heat treating the electrode material-polymer fiber composite to remove polymer fibers;
Containing,
Method for manufacturing a room temperature driven gas sensor.
The method of claim 11,
Forming the electrode material-polymer fiber composite is to deposit the electrode material,
Method for manufacturing a room temperature driven gas sensor.
The method of claim 11,
The spinning solution comprises a polymer material or a polymer material and a metal oxide,
The polymer material may be polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene oxide (PEO), carboxymethyl cellulose (CMC), starch, polyacrylic acid (PA), hyaluronic acid ( Hyaluronic acid), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylacetate (PVAc) and PVC (polyvinylchloride),
The metal oxide may be silver (Ag), copper (Cu), gold (Au), chromium (Cr), aluminum (Al), tungsten (W), zinc (Zn), nickel (Ni), iron (Fe), At least one selected from the group consisting of oxides including at least one of platinum (Pt), lead (Pb), magnesium (Mg), titanium (Ti), molybdenum (Mo), cobalt (Co),
Method for manufacturing a room temperature driven gas sensor.
The method of claim 11,
Arranging the polymer fibers, the polymer fibers are electrospun perpendicular to the extending direction of the plurality of electrode frames,
Method for manufacturing a room temperature driven gas sensor.
The method of claim 11,
Removing the polymer fibers, the heat treatment at a temperature of 200 ℃ or more,
Method for manufacturing a room temperature driven gas sensor.

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