Coordination polymer, synthesis method of coordination polymer and gas sensor using same

Abstract

A coordination polymer according to the present invention comprises a coordination polymer represented by chemical formula 1.

Description

Coordination polymer, method for producing coordination polymer, and gas sensor using the same

[0001] The present invention relates to a coordination polymer, a method for producing a coordination polymer, and a gas sensor using the same.

[0002] Gas sensors are widely used across society. In industry, hazardous gas alarms detect hazardous gas leaks early, preventing major accidents and loss of life. In more practical settings, they are used as air pollution meters or indoor air quality monitors, monitoring the overall air quality in living spaces and providing a pleasant environment.

[0003] Among the various materials that can be used as sensing materials in gas sensors, metal oxides are the most widely used due to their simple sensing principles and excellent applicability. Metal oxide semiconductor-based resistive gas sensors detect gases by measuring the resistance changes resulting from gas adsorption and desorption on the surface of the sensing material.

[0004] However, since gas sensors using metal oxides (MOX, metal oxide gas sensors) must have an operating temperature above a certain level, development of gas sensors that operate at room temperature (RT) is required in order to go beyond simple industrial gas sensors and be used in real life or applied to the biomedical field.

[0005] Accordingly, a polymer gas sensor using a polymer rather than a gas sensor using a metal oxide was proposed.

[0006] However, while polymer-based gas sensors can operate at room temperature, their gas responsiveness falls short of that of metal oxide-based gas sensors. Furthermore, the fundamental drawback of polymer synthesis is the tedious and time-consuming steps involved, necessitating the development of materials that can address these shortcomings.

[0007] The present invention aims to provide a coordination polymer that is simple to synthesize and can produce a gas sensor having high gas responsiveness when applied to a gas sensor.

[0008] In addition, the present invention seeks to provide a method for producing a coordination polymer, which is very simple to produce and allows the production of a coordination polymer in a short production time.

[0009] In addition, the present invention seeks to provide a gas sensor that can operate at room temperature and has excellent gas responsiveness.

[0010] The present invention provides a coordination polymer represented by chemical formula 1.

[0011] [Chemical Formula 1]

[0012]

[0013] In the above chemical formula 1,

[0014] CC is any one of the compounds represented by chemical formulas 2 and 3 that is coordinately bonded to M,

[0015] M is a transition metal,

[0016] X is a halogen element,

[0017] n is an integer between 5 and 500,000,

[0018] [Chemical Formula 2]

[0019]

[0020]

[0021] [Chemical Formula 3]

[0022]

[0023] In the above chemical formulas 2 and 3,

[0024] A is an element of group 16 independently of each other,

[0025] R1 to R3 are each independently an acyclic compound or a derivative of an acyclic compound.

[0026] In addition, the present invention provides a method for producing a coordination polymer, comprising the steps of preparing a metal precursor, a compound represented by chemical formulae 2 and 3 as a binding functional group, and a solvent; and a step of reacting a synthetic solution in which the metal precursor, the binding functional group, and the solvent are mixed to form a coordination polymer represented by chemical formula 1.

[0027] [Chemical Formula 1]

[0028]

[0029] In the above chemical formula 1,

[0030] CC is any one of the compounds represented by chemical formulas 2 and 3 that is coordinately bonded to M,

[0031] M is a transition metal,

[0032] X is a halogen element,

[0033] n is an integer between 5 and 500,000,

[0034] [Chemical Formula 2]

[0035]

[0036]

[0037] [Chemical Formula 3]

[0038]

[0039] In the above chemical formulas 2 and 3,

[0040] A is an element of group 16 independently of each other,

[0041] R1 to R3 are each independently an acyclic compound or a derivative of an acyclic compound.

[0042] In addition, the present invention provides a gas sensor comprising: a substrate; a gas sensing region provided on at least a portion of the substrate; a first electrode electrically connected to the gas sensing region and spaced apart from each other; and a second electrode; wherein the gas sensing region contains the aforementioned coordination polymer.

[0043] The coordination polymer according to the present invention has the advantage of being simple to manufacture and being able to provide excellent gas responsiveness when applied to a gas sensor.

[0044] The method for producing a coordination polymer according to the present invention has the advantage of being able to produce a coordination polymer in a simple manner.

[0045] The gas sensor according to the present invention has the advantage of being able to operate at room temperature while having excellent gas responsiveness.

[0046] FIG. 1 is an SEM image of a coordination polymer manufactured according to some embodiments of the present invention.

[0047] FIG. 2 shows the results of XRD analysis of a coordination polymer manufactured according to some embodiments of the present invention.

[0048] FIG. 3 is an EDS mapping image of a coordination polymer manufactured according to some embodiments of the present invention.

[0049] Figure 4 shows the XPS analysis results of a coordination polymer manufactured according to some embodiments of the present invention.

[0050] FIG. 5 is an SEM image of a coordination polymer manufactured according to some embodiments of the present invention.

[0051] Figure 6 shows the results of XRD analysis of a coordination polymer manufactured according to some embodiments of the present invention.

[0052] Figure 7 shows the results of measuring the permeability of a coordination polymer manufactured according to some embodiments of the present invention.

[0053] Figure 8 shows the XPS analysis results of a coordination polymer manufactured according to some embodiments of the present invention.

[0054] FIG. 9 is an SEM image of an Ag-doped coordination polymer manufactured according to some embodiments of the present invention.

[0055] FIG. 10 is a TEM image of an Ag-doped coordination polymer manufactured according to some embodiments of the present invention.

[0056] FIG. 11 is an EDS mapping image of a coordination polymer manufactured according to some embodiments of the present invention.

[0057] Figure 12 is XPS data of a coordination polymer manufactured according to some embodiments of the present invention.

[0058] FIG. 13 shows the XRD analysis results of Ag-doped coordination polymers manufactured according to some embodiments of the present invention.

[0059] Figures 14 and 15 are images of gas sensors manufactured according to some embodiments of the present invention.

[0060] FIG. 16 is a diagram showing the results of a gas selectivity experiment of a gas sensor manufactured according to some embodiments of the present invention.

[0061] Figures 17 to 20 are diagrams showing the results of gas responsiveness experiments of gas sensors manufactured according to some embodiments of the present invention.

[0062] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0063] In the present invention, when it is said that a member is located “on” another member, this includes not only cases where a member is in direct contact with another member, but also cases where another member is interposed between the two members.

[0064] When a part of the present invention is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless otherwise specifically stated.

[0065]

[0066] Coordination polymer

[0067] One aspect of the present invention relates to a coordination polymer represented by the following chemical formula 1.

[0068]

[0069] [Chemical Formula 1]

[0070]

[0071] In the above chemical formula 1,

[0072] CC is any one of the compounds represented by chemical formulas 2 and 3 that is coordinately bonded to M,

[0073] M is a transition metal,

[0074] X is a halogen element,

[0075] n is an integer between 5 and 500,000,

[0076] [Chemical Formula 2]

[0077]

[0078] [Chemical Formula 3]

[0079]

[0080] In the above chemical formulas 2 and 3,

[0081] A is an element of group 16 independently of each other,

[0082] R1 to R3 are each independently an acyclic compound or a derivative of an acyclic compound.

[0083]

[0084] In one embodiment of the present invention, the transition metal may be at least one selected from the group consisting of copper (Cu), manganese (Mn), iron (Fe), cadmium (Cd), cobalt (Co), nickel (Ni), zinc (Zn), mercury (Hg), molybdenum (Mo), titanium (Ti), magnesium (Mg), chromium (Cr), and antimony (Sb).

[0085] Specifically, the transition metal may be copper. When the transition metal is copper, the raw material cost can be relatively reduced compared to other transition metals, and when manufacturing a sensor using the coordination polymer, it can have good electrical conductivity at room temperature, which is preferable.

[0086]

[0087] In another embodiment of the present invention, the halogen element may be at least one selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

[0088] Specifically, the halogen element may be chlorine. If the halogen element is chlorine, it is preferable because it has a superior advantage in terms of reducing raw material costs compared to other halogen elements.

[0089] The above n is the number of repetitions and may be preferably 3 to 20,000, more preferably 100 to 10,000.

[0090]

[0091] The coordination polymer represented by the above chemical formula 1 includes a compound represented by the above chemical formula 2 or 3 as a functional group for bonding. The compound represented by the above chemical formula 2 or 3 has a hydrogen element and an element for hydrogen bonding or coordination bonding, and the element for hydrogen bonding or coordination bonding can form a hydrogen bond or coordination bond by donating an unshared electron pair to the transition metal (M) of the above chemical formula 1.

[0092]

[0093] In the above chemical formula 2 or 3, A as an element for hydrogen bonding or coordination bonding is a group 16 element.

[0094] In one embodiment of the present invention, A may be at least one selected from the group consisting of oxygen (O), sulfur (S), selenium (Se), and tellurium (Te).

[0095] In another embodiment of the present invention, A may be sulfur (S).

[0096] In the case where the above A is sulfur, it is relatively easy to synthesize compared to the material containing Se and Te, and it exhibits appropriate electrical conductivity compared to the material containing Se and Te, making it suitable for application to a gas sensor that measures the change in resistance of the sensor, and it is advantageous in that it is possible to produce a material applicable to a gas sensor at low cost.

[0097] Specifically, the coordination polymer according to the present invention may be formed of a thiourea containing an acyclic compound.

[0098]

[0099] In another embodiment of the present invention, the acyclic compound may independently be a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C2 to C20 alkoxyalkyl group.

[0100] In the present invention, the term "substituted or unsubstituted" means substituted with one or more substituents selected from the group consisting of a hydroxy group, -OSiRaRbRc, -SiRdReRf, -NRgRh, an ester group, a carbonate group, a carbonyl group, a thio group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C2-C20 alkylene oxide group, or a combination thereof, or has no substituents. Here, Ra to Rf are the same or different and are hydrogen, a hydroxyl group, an ester group, a carbonate group, a carbonyl group, a thio group, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C2-C20 alkylene oxide group, or a combination thereof, and Rg and Rh are the same or different and are each independently a C1-C20 alkyl group.

[0101] In the present invention, the “combination” of substituents means a structure in which two or more substituents are combined.

[0102] The above alkyl group may be straight or branched, and preferably has C1 to C10 carbon atoms. The alkyl group includes, but is not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, and the like.

[0103] In the present invention, “alkenyl group” may refer to a monovalent straight-chain or branched-chain aliphatic unsaturated hydrocarbon containing one or more carbon-carbon double bonds.

[0104] The above alkenyl group may preferably have C2 to C10 carbon atoms. The above alkenyl group may be, for example, ethenyl, vinyl, propenyl, allyl, isopropenyl, butenyl, isobutenyl, n-pentenyl, n-hexenyl, etc., but is not limited thereto.

[0105] In the present invention, “alkynyl group” may refer to a monovalent straight-chain or branched-chain aliphatic unsaturated hydrocarbon containing one or more carbon-carbon triple bonds.

[0106] The above alkynyl group may preferably have carbon atoms of C2 to C10. The alkynyl group is, for example, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methyl-2-propynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-methyl-2-butynyl, 1-methyl-3-butynyl, 2-methyl-3-butynyl, 3-methyl-1-butynyl, 1,1-dimethyl-2-propynyl, 1-ethyl-2-propynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, 1-methyl-2-pentynyl, 1-methyl-3-pentynyl, 1-methyl-4-pentynyl, 2-methyl-3-pentynyl, 2-methyl-4-pentynyl, 3-methyl-1-pentynyl, 3-methyl-4-pentynyl, 4-methyl-1-pentynyl, 4-methyl-2-pentynyl, 1,1-dimethyl-2-butynyl, 1,1-dimethyl-3-butynyl, 1,2-dimethyl-3-butynyl, 2,2-dimethyl-3-butynyl, 3,3-dimethyl-1-butynyl, 1-ethyl-2-butynyl, 1-ethyl-3-butynyl, 2-ethyl-3-butynyl, 1-ethyl-1-methyl-2-propynyl, and 2,5-hexadiynyl, but are not limited thereto.

[0107] The alkoxy group may preferably have C1 to C10 carbon atoms. The alkoxy group may be, for example, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a tert-butoxy group, an n-pentoxy group, an iso-pentoxy group, or a neo-pentoxy group, but is not limited thereto.

[0108] The above alkoxyalkyl may be a substituent having a structure including -Ra-O-Rb, wherein at least one hydrogen of alkyl (-Ra) is replaced with alkoxy (-O-Rb). The alkoxyalkyl may preferably have C2 to C10 carbon atoms. The alkoxyalkyl may be, for example, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an iso-propoxymethyl group, an iso-propoxyethyl group, an iso-propoxyhectyl group, a tert-butoxymethyl group, a tert-butoxyethyl group, or a tert-butoxyhexyl group, but is not limited thereto.

[0109] According to one embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C1 to C20 alkyl group.

[0110] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C1 to C10 alkyl group.

[0111] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C1 to C6 alkyl group.

[0112] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur and R1 is a methyl group.

[0113] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C2 to C20 alkoxyalkyl group.

[0114] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C2 to C10 alkoxyalkyl group.

[0115] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C2 to C6 alkoxyalkyl group.

[0116] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur and R1 is a methoxyethyl group.

[0117] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C2 to C10 alkenyl group.

[0118] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is an alkenyl group having C2 to C8.

[0119] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur, and R1 is a C2 to C6 alkenyl group.

[0120] According to another embodiment of the present invention, in the chemical formula 2, A is sulfur and R1 is an allyl group.

[0121]

[0122] The coordination polymer represented by chemical formula 1 according to the present invention, specifically the coordination polymer formed with a thio element including an acyclic compound, has higher electrical conductivity than other coordination polymers formed with oxygen or nitrogen and metal due to the main bond formed with sulfur and copper, and thus, when applied to a gas sensor, a gas sensor with high gas responsiveness can be manufactured.

[0123] Although not wishing to be limited by theory, the coordination polymer represented by the chemical formula 1 according to the present invention has an advantage in that the coordination polymer formed with an infinitely connected AM bond structure, for example, a thio element including an acyclic compound, exhibits high gas sensing performance because it has excellent electrical conductivity and is advantageous for electron exchange due to the infinitely connected sulfur-copper bond structure.

[0124]

[0125] <Method for producing coordination polymers>

[0126] Another aspect of the present invention relates to a method for producing a coordination polymer, comprising the steps of: preparing a metal precursor, a compound represented by any one of the following chemical formulae 2 and 3 as a binding functional group, and a solvent; and reacting a synthetic solution in which the metal precursor, the binding functional group, and the solvent are mixed to form a coordination polymer represented by the following chemical formula 1.

[0127] [Chemical Formula 1]

[0128]

[0129] In the above chemical formula 1,

[0130] CC is any one of the compounds represented by chemical formulas 2 and 3 that is coordinately bonded to M,

[0131] M is a transition metal,

[0132] X is a halogen element,

[0133] n is an integer between 5 and 500,000,

[0134] [Chemical Formula 2]

[0135]

[0136]

[0137] [Chemical Formula 3]

[0138]

[0139] In the above chemical formulas 2 and 3,

[0140] A is an element of group 16 independently of each other,

[0141] R1 to R3 are each independently an acyclic compound or a derivative of an acyclic compound.

[0142] The compounds represented by the above chemical formulas 1 to 3 can be applied with the above-described contents.

[0143]

[0144] The method for producing a coordination polymer according to the present invention comprises the steps of preparing a metal precursor, a compound represented by the above chemical formulas 2 and 3 as a functional group for bonding, and a solvent.

[0145]

[0146] In another embodiment of the present invention, the metal precursor may be represented by the following chemical formula 4.

[0147] [Chemical Formula 4]

[0148]

[0149] In the above chemical formula 4,

[0150] M is a transition metal,

[0151] X is a halogen element.

[0152]

[0153] In the above chemical formula 4, M and X can be applied as described above.

[0154]

[0155] In another embodiment of the present invention, the solvent may be a hydrophilic solvent. For example, the solvent may be at least one selected from, but is not limited to, water, methanol, ethanol, isopropanol, tertiary butanol, tertiary amyl alcohol, methyl glycol, butoxyethanol, methoxy propanol, methoxypropoxypropanol, ethylene glycol, water-soluble oligomers of ethylene glycol, propylene glycol, water-soluble oligomers of propylene glycol, alcohols such as glycerol; ethers such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, glycerol ether; and ketones such as acetone, methyl ethyl ketone, and dioxane.

[0156] Specifically, the solvent may be ethanol.

[0157]

[0158] The method for producing a coordination polymer according to the present invention includes a step of reacting a synthetic solution in which the metal precursor, the binding functional group, and the solvent are mixed to form a coordination polymer represented by the following chemical formula 1.

[0159] In another embodiment of the present invention, the reaction may be performed by stirring, sonication, or a combination thereof.

[0160] The metal precursor may be included in an amount of 0.0001 to 5 parts by weight, preferably 0.0001 to 3 parts by weight, more preferably 0.005 to 0.5 parts by weight, and most preferably 0.001 to 0.05 parts by weight, based on 100 parts by weight of the total synthetic solution.

[0161] When the content of the metal precursor satisfies the above range, it is preferable because it has the advantage of being able to maintain the ratio of functional groups and metals in the product.

[0162]

[0163] The above-mentioned binding functional group may be included in an amount of 0.0001 to 1 part by weight, preferably 0.0001 to 3 parts by weight, more preferably 0.005 to 0.5 parts by weight, and most preferably 0.001 to 0.05 parts by weight, based on 100 parts by weight of the total synthetic solution.

[0164] When the content of the functional group for the above bonding satisfies the above range, it is advantageous in that the ratio of the functional group and the metal in the product can be maintained.

[0165]

[0166] The solvent may be included in an amount of 90 to 99 parts by weight, preferably 92 to 99 parts by weight, and more preferably 93 to 99 parts by weight, based on 100 parts by weight of the total synthetic solution.

[0167] When the content of the above solvent satisfies the above range, it is preferable because there is an advantage that the precursor is sufficiently dissolved.

[0168]

[0169] The above reaction may be carried out at, for example, 10 to 25°C, preferably 20 to 25°C, and more preferably at room temperature, but is not limited thereto.

[0170] However, when the reaction temperature is within the above range, it is preferable because there is an advantage in that the solubility of the synthesized coordination polymer is low depending on the temperature.

[0171] The above reaction time may be performed for, for example, 3 to 60 minutes, preferably 10 to 20 minutes, more preferably 10 to 15 minutes, but is not limited thereto.

[0172] However, if the reaction time is within the above range, it is preferable because it has the advantage of being synthesized in a shorter time compared to other coordination polymers.

[0173]

[0174] The method for producing a coordination polymer according to the present invention has the advantage of forming a coordination polymer represented by the above chemical formula 1 through a simple reaction such as stirring or ultrasonic treatment, and easily producing the coordination polymer by using hydrogen bonds between the coordination polymers and an acyclic compound and its derivatives.

[0175]

[0176] Gas Sensor

[0177] Another aspect of the present invention relates to a gas sensor comprising: a substrate; a gas sensing region provided on at least a portion of the substrate; a first electrode electrically connected to the gas sensing region and spaced apart from each other; and a second electrode; wherein the gas sensing region contains the aforementioned coordination polymer.

[0178] Materials used for the above substrate include, but are not limited to, III-V compound semiconductors such as Si, GaAs, InP, and InGaAs, glass, polymers, oxide thin films, dielectric thin films, metal thin films, and flexible substrates.

[0179] Preferably, the substrate may be a silicon substrate, and specifically, it may be a silicon substrate having an insulating film formed on the surface, for example, a silicon substrate having a silicon oxide film (SiO2) formed on the surface (SiO2 / Si substrate), but is not limited thereto.

[0180] The above insulating film may be formed on the substrate by a method such as thermal oxidation, deposition, or spin coating, but is not limited thereto.

[0181] The first electrode and the second electrode, which are electrically connected to the gas detection region and are spaced apart from each other on the upper portion of the substrate, may be a source electrode and a drain electrode.

[0182] The electrode may include, but is not limited to, one or more metals selected from the group consisting of gold (Au), silver (Ag), chromium (Cr), tantalum (Ta), titanium (Ti), copper (Cu), aluminum (Al), molybdenum (Mo), tungsten (W), nickel (Ni), palladium (Pd), and platinum (Pt).

[0183] The above gas sensing region comprises the above-described coordination polymer.

[0184] The above coordination polymer can be applied to the above-described content.

[0185] The above coordination polymer may be doped with a doping metal.

[0186] The above doping metal may be a transition metal. The above-described transition metal may be applied. The above doping metal may be appropriately selected depending on the performance of the intended gas sensor.

[0187]

[0188] The present invention does not limit the manufacturing method of the gas sensor. For example, the gas sensing region including the coordination polymer may be formed using, but is not limited to, dip coating, which involves immersing the substrate in a solution including the coordination polymer and then removing it, drop casting, which involves dropping the solution including the coordination polymer onto the substrate, or spray coating, which involves spraying the solution including the coordination polymer.

[0189] When the above coordination polymer is doped with the doping metal, the coordination polymer doped with the doping metal can be easily manufactured by simply mixing the coordination polymer and the doping metal.

[0190] The above doping metal may be included in an amount of 0.0001 to 2 parts by weight, preferably 0.0005 to 1 part by weight, and more preferably 0.01 to 0.5 parts by weight, relative to 100 parts by weight of the entire coordination polymer. When the above doping metal is included within the above range, it is preferable because it has the advantage of improving only the detection performance without significantly changing the structure.

[0191] Specifically, it can be obtained by adding the coordination polymer and the doping metal to a solvent and then stirring. A gas sensor having excellent gas responsiveness can be obtained simply by stirring the coordination polymer and the doping metal together.

[0192] The above solvent may be a hydrophilic solvent, and the above-described content may be applied to the hydrophilic solvent.

[0193] In short, the coordination polymer according to the present invention can serve as a gas sensing material.

[0194]

[0195] The gas sensor according to the present invention, which contains the coordination polymer as a gas-sensing material, has the advantage of excellent gas responsiveness and operation at room temperature. Therefore, it can be usefully utilized across a wide range of industries, including the biomedical field.

[0196]

[0197] Hereinafter, preferred embodiments and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0198]

[0199] Synthesis Example 1

[0200] N-Methylthiourea (0.7 mmol) was dissolved in 100 ml of ethanol (EtOH) at room temperature (25°C). After N-methylthiourea was completely dissolved, 100 mg of CuCl2 was additionally added and stirred at room temperature (25°C) for 10 minutes. Afterwards, the mixture was filtered to obtain a powder-form coordination polymer (methyl thiourea - Cu complex coordination polymer (MT)).

[0201] The coordination polymer manufactured according to Synthesis Example 1 could be easily synthesized within 10 minutes.

[0202] Figure 1 is a SEM image of a coordination polymer manufactured according to Synthesis Example 1. Referring to Figure 1, it can be seen that the manufactured coordination polymer is in the form of a nanowire with a thickness of approximately 0.1 μm and a length of several tens of μm.

[0203] Figure 2 shows the XRD analysis results of the coordination polymer manufactured according to Synthesis Example 1. Referring to Figure 2, the main crystal plane of the coordination polymer can be identified.

[0204] Figure 3 is an EDS mapping image of a coordination polymer manufactured according to Synthesis Example 1. Looking at Figure 3, it can be seen that the main components Cu, S, Cl, and N are evenly distributed throughout the nanowire.

[0205] Figure 4 shows the XPS analysis results of the coordination polymer manufactured according to Synthesis Example 1. Looking at Figure 4, it can be seen that the manufactured coordination polymer is composed of C, N, S, Cl, Cu components, etc. In addition, it can be seen that Cu is monovalent.

[0206] Additionally, it was found that the electrode had electrical conductivity at room temperature through resistance measurement using a multimeter after application.

[0207]

[0208] Synthesis Example 2

[0209] 0.7 mmol of (2-methoxyethyl)thiourea was dissolved in 100 ml of ethanol (EtOH) at room temperature of 25°C. After (2-methoxyethyl)thiourea was completely dissolved, 100 mg of CuCl2 was additionally added and stirred at room temperature of 25°C for 10 minutes. Afterwards, the mixture was filtered to obtain a powder-type coordination polymer ((2-Methoxyethyl)thiourea - Cu complex coordination polymer (MET)).

[0210] The coordination polymer manufactured according to Synthesis Example 2 could be easily synthesized within 10 minutes.

[0211] Figure 5 is a SEM image of a coordination polymer manufactured according to Synthesis Example 2. Referring to Figure 5, it can be seen that the manufactured coordination polymer has a nanoplate shape with a thickness of about 0.1 μm and a length of about 2 to 5 μm.

[0212] Figure 6 shows the XRD analysis results of the coordination polymer manufactured according to Synthesis Example 2. Referring to Figure 6, the main crystal plane of the coordination polymer can be identified.

[0213] Figure 7 shows the results of a transmittance measurement of a coordination polymer manufactured according to Synthesis Example 2. The transmittance was measured using Fourier transform infrared spectroscopy. Referring to Figure 7, it can be seen that the functional groups of the manufactured coordination polymer remain intact even after synthesis.

[0214] Figure 8 shows the XPS analysis results of the coordination polymer manufactured according to Synthesis Example 2. Referring to Figure 8, it can be seen that the manufactured coordination polymer is composed of C, N, O, S, Cl, and Cu components. It can also be seen that Cu is monovalent.

[0215] In addition, as in Synthesis Example 1, it was found that the electrode had electrical conductivity at room temperature through resistance measurement using a multimeter after application.

[0216]

[0217] Synthesis Example 3

[0218] 0.7 mmol of N-methylthiourea was dissolved in 100 ml of ethanol (EtOH) at room temperature of 25°C. After N-methylthiourea was completely dissolved, 100 mg of CuCl2 was additionally added and stirred at room temperature of 25°C for 10 minutes.

[0219] After stirring, the mixture was washed three times in a centrifuge at 6000 rpm for 5 min. After washing, 100 ml of ethanol and 0.168 ml of Ag solution were added and stirred for 2 h. After stirring, the mixture was washed three times in a centrifuge at 6000 rpm for 5 min to obtain a Ag-doped coordination polymer (Methyl thiourea - Cu complex coordination polymer (MT)).

[0220] Fig. 9 shows an SEM image of the Ag-doped coordination polymer manufactured according to Synthesis Example 3, and Fig. 10 shows a TEM image.

[0221] Figure 11 is an EDS mapping image of a coordination polymer manufactured according to Synthesis Example 3.

[0222] Figure 12 is XPS data of a coordination polymer manufactured according to Synthesis Example 3.

[0223] Referring to Figures 11 and 12, doped Ag is Ag 1+ It can be seen that it exists in a state and is exchanged at the Cu site.

[0224] In addition, by comparing Fig. 13 and Fig. 2, it can be seen that the exchange was carried out without causing any structural damage to the existing coordination polymer material.

[0225] Additionally, it can be seen that performance can be improved simply by mixing a doping element into an existing coordination polymer.

[0226]

[0227] Example 1

[0228] A gas sensor was manufactured using the coordination polymer manufactured according to Synthesis Example 1.

[0229] Specifically, the coordination polymer manufactured according to Synthesis Example 1 was placed in a centrifuge and washed three times at 6000 rpm for 5 min. After washing, the entire supernatant was discarded, 1 ml of ethanol was added, and mixed well.

[0230] After drop casting 50 μl on the prepared substrate, the gas sensor (Normal MT) using the coordination polymer manufactured according to Synthesis Example 1 was manufactured by drying at 65°C.

[0231] At this time, a gas sensor sample was formed by depositing a solution containing a coordination polymer to a thickness of 4 μm using a pipette on a substrate on which a gold electrode was deposited. An image of the manufactured gas sensor is shown in Figure 14.

[0232]

[0233] Example 2

[0234] A gas sensor (MET) using the coordination polymer manufactured according to Synthesis Example 2 was manufactured in the same manner as Example 1, except that the coordination polymer manufactured according to Synthesis Example 2 was used. An image of the manufactured gas sensor is shown in Fig. 15.

[0235]

[0236] Example 3

[0237] A gas sensor (Ag-doped MT) using a coordination polymer manufactured according to Synthesis Example 3 was manufactured in the same manner as Example 1, except that the Ag-doped coordination polymer manufactured according to Synthesis Example 3 was used.

[0238]

[0239] Experimental example

[0240] The performance of the gas sensor manufactured according to the example was tested. All sensor tests were conducted at RT (room temperature, 25°C) using dry NH3 gas.

[0241]

[0242] (1) Gas selectivity

[0243] In order to determine the gas selectivity of the gas sensor manufactured according to Example 1, the RT operation NH3 target gas responsiveness was measured, and the results are shown in Fig. 16. In order to increase the reliability of the gas selectivity for NH3, three gas sensors were manufactured according to Example 1 using each synthesized sample from the same batch, and their performances were tested. Each sample was measured once, and each data is represented in black (a), red (b), and blue (c) in Fig. 16. Specifically, the gas responsiveness was measured by sequentially exposing the three samples manufactured in Example 1 to 100 ppm acetone, 100 ppm ethanol, 100 ppm ammonia, 5 ppm nitrogen dioxide, 100 ppm hydrogen, and 100 ppm hexane, and after exposing each gas for 10 minutes, exposing it to nitrogen for 20 minutes to minimize the influence of the previous gas.

[0244] Referring to Figure 16, the selectivity test results showed a response of approximately 1000% in NH3 and showed little change in other VOC gases except for NO2, showing a large difference in response and demonstrating high selectivity.

[0245] In addition, when exposed to gas conditions, the resistance increased under NH3 conditions and decreased under NO2 conditions, indicating that a p-type sensor was formed.

[0246]

[0247] (2) Gas responsiveness 1

[0248] The gas reactivity was measured based on the resistance of the gas sensors manufactured according to Examples 1 and 3, and the results are shown in Figs. 17 and 18. Specifically, the samples prepared according to Examples 1 and 3 were measured at room temperature at various concentrations of NH3 gas (100 to 0.25 ppm). During each measurement, after exposure to NH3 gas, the sensor was also exposed to Ar gas for desorption of the gas, and this is considered one cycle.

[0249] Referring to FIGS. 16 and 17, when NH3 gas was 5, 10, 20, 50, and 100 ppm in the high concentration range, the gas sensor (normal MT) manufactured according to Example 1 showed gas responsiveness of 80, 110, 191, 300, and 500%, and the gas sensor (Ag-doped MT) manufactured according to Example 3 showed very high gas responsiveness of 180, 317, 650, 1210, and 3000%.

[0250] Even at the lowest testable concentration of 0.25 ppm, the gas sensor (Ag-doped MT) manufactured according to Example 3 exhibited a gas response of 6%, demonstrating that it is a usable gas sensor across the entire concentration range. Furthermore, the response and recovery time, which are considered as performance evaluation criteria for gas sensors, could also be improved by using the Ag-doped coordination polymer.

[0251]

[0252] (3) Gas responsiveness 2

[0253] Based on the resistance of the gas sensor manufactured according to Example 2, the gas reactivity was measured, and the results are shown in Figs. 19 and 20. Specifically, the sample prepared according to Example 2 was measured at room temperature at various concentrations of NH3 gas (100 to 0.25 ppm). During each measurement, after exposure to NH3 gas, the sensor was also exposed to Ar gas for desorption of the gas, and this is considered one cycle.

[0254] Referring to FIGS. 19 and 20, the gas sensor (normal MET) manufactured according to Example 2 exhibited very high gas responsiveness of 1200, 8700, 40000, and 200000% when NH3 gas was in the high concentration range of 10, 20, 50, and 100 ppm, respectively. This is a very high gas responsiveness that is thousands or tens of thousands of times higher than that of other room-temperature-operated gas sensors based on 100 ppm. In addition, despite the very high gas responsiveness, the recovery characteristics at room temperature are very excellent.

[0255] Even in the low concentration range, the gas sensor using the gas sensor (normal MET) manufactured according to Example 2 showed a gas response of 6,315% at 0.25 ppm and 5 ppm, proving that it is a gas sensor that can be used even at low concentrations.

[0256]

[0257] The present invention is not limited to the above-described embodiments, but can be manufactured in a variety of different forms. Those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Coordination polymer represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, CC is any one of the compounds represented by chemical formulas 2 and 3 that is coordinately bonded to M, M is a transition metal, X is a halogen element, n is an integer between 5 and 500,000, [Chemical Formula 2] [Chemical Formula 3] In the above chemical formulas 2 and 3, A is an element of group 16 independently of each other, R1 to R3 are each independently an acyclic compound or a derivative of an acyclic compound.

2. In paragraph 1, A coordination polymer wherein the above-mentioned acyclic compound is independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C2 to C20 alkoxyalkyl group.

3. In paragraph 1, A coordination polymer wherein the above transition metal is at least one selected from the group consisting of copper (Cu), manganese (Mn), iron (Fe), cadmium (Cd), cobalt (Co), nickel (Ni), zinc (Zn), mercury (Hg), molybdenum (Mo), titanium (Ti), magnesium (Mg), chromium (Cr), and antimony (Sb).

4. In paragraph 1, A coordination polymer wherein the above halogen element is at least one selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

5. In paragraph 1, A coordination polymer wherein the above A is at least one selected from the group consisting of oxygen (O), sulfur (S), selenium (Se), and tellurium (Te).

6. In paragraph 5, The above A is a coordination polymer having sulfur (S).

7. A step of preparing a metal precursor, a compound represented by the following chemical formulas 2 and 3 as a functional group for bonding, and a solvent; and A step of forming a coordination polymer represented by the following chemical formula 1 by reacting a synthetic solution in which the metal precursor, the binding functional group, and the solvent are mixed; Method for producing a coordination polymer comprising: [Chemical Formula 1] In the above chemical formula 1, CC is any one of the compounds represented by chemical formulas 2 and 3 that is coordinately bonded to M, M is a transition metal, X is a halogen element, n is an integer between 5 and 500,000, [Chemical Formula 2] [Chemical Formula 3] In the above chemical formulas 2 and 3, A is an element of group 16 independently of each other, R1 to R3 are each independently an acyclic compound or a derivative of an acyclic compound.

8. In paragraph 7, The above metal precursor is a method for producing a coordination polymer represented by the following chemical formula 4: [Chemical Formula 4] In the above chemical formula 4, M is a transition metal, X is a halogen element.

9. In paragraph 7, A method for producing a coordination polymer, wherein the above solvent is a hydrophilic solvent.

10. In paragraph 7, A method for producing a coordination polymer, wherein the above reaction is performed by stirring, ultrasonic treatment, or a combination thereof.

11. Substrate; A gas detection area provided on at least a portion of the above substrate; A first electrode electrically connected to the gas detection area and spaced apart from each other; and a second electrode; A gas sensor wherein the gas sensing region contains a coordination polymer according to any one of claims 1 to 6.

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