WO2022211254A1 - Ion sensor - Google Patents

Abstract

The present invention relates to an ion sensor, and more specifically, to an ion sensor comprising: a substrate; a working electrode disposed on the substrate and including a conductive layer, an electron transport layer, and an ion-selective layer; and a reference electrode. Accordingly, the ion sensor has excellent sensing sensitivity and speed, and can have improved accuracy and reliability.

Description

ion sensor

The present invention relates to an ion sensor. More particularly, it relates to an ion sensor comprising a working electrode and a reference electrode.

Recently, as interest in clinical chemistry such as hemodialysis and telemedicine diagnosis, environmental analysis such as water quality analysis, and food chemistry such as fermentation process has increased, it is possible to measure changes in various chemical substances included in measurement objects such as blood and sweat. There is a growing demand for chemical sensors.

A chemical sensor is a sensor that detects a specific ion present in a sample to be measured and measures the potential difference corresponding to the concentration and activity of the ion. Therefore, selectivity and sensitivity characteristics for accurately selecting and rapidly detecting a measurement target ion from among various ions included in a measurement target sample are important.

However, in the conventional ion sensor, selectivity and sensitivity are easily lowered according to various measurement environments such as the concentration of the sample to be measured, ambient temperature, and pressure, so it is difficult to accurately detect the concentration of the ion to be measured. Therefore, there is a demand for research and development of an ion sensor having excellent selectivity and sensitivity with respect to the ion to be measured.

For example, Korean Patent Laid-Open Publication No. 10-2013-0107609 discloses an ion sensor using a potential difference method.

An object of the present invention is to provide an ion sensor having improved sensing sensitivity and sensing resolution.

1. Substrate; A conductive layer disposed on the substrate and disposed on an upper surface of the substrate, an electron transport layer disposed on the upper surface of the conductive layer and comprising a conductive binder and a metal complex dispersed in the conductive binder, and the electron transport a working electrode comprising an ion selective layer disposed on a top surface of the layer; and a reference electrode disposed on the substrate to be spaced apart from the working electrode.

2. The ion sensor according to 1 above, wherein the conductive layer includes a metal layer and a metal protective layer disposed on an upper surface of the metal layer.

3. The ion sensor according to the above 2, wherein the metal layer includes at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof.

4. The ion sensor according to 2 above, wherein the metal protective layer includes a transparent conductive oxide.

5. The ion sensor according to 1 above, wherein the conductive binder includes a carbon paste, a metal-containing paste, or a conductive polymer.

6. In the above 1, the metal complex is Prussian blue, potassium ferricyanide, potassium ferrocyanide, hexaamine ruthenium (III) chloride (Hexaammineruthenium (III) chloride) , An ion sensor comprising at least one selected from the group consisting of a ferrocene-based compound, a quinone-based compound, and a hydroquinone-based compound.

7. The ion sensor according to the above 1, wherein the metal complex is included in an amount of 0.01 wt% to 10 wt% of the total weight of the electron transport layer.

8. The ion sensor according to 1 above, wherein the ion-selective layer comprises an ion-sensitive material and a polymer support.

9. The above 8, wherein the ion-sensitive material is H ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , OH ^- , Cl ^- , F ^- , Br ^- , I ^- , CN ^- and NO ₃ ^- An ion sensor comprising a material that selectively transmits one ion selected from the group consisting of.

10. In the above 8, the polymer support is polyvinyl chloride, polyvinyl chloride carboxylate, polyvinyl chloride aminate, polyvinyl butyral, polyvinyl alcohol, polymethyl acrylate, polyethylene oxide, xerogel, agar Rose, comprising at least one selected from the group consisting of polyurethane and silicone rubber, 　 ion 　 sensor.

11. The ion sensor according to the above 1, wherein the thickness of the ion selective layer is thicker than the thickness of the electron transport layer.

12. The ion sensor according to the above 11, wherein the electron transport layer has a thickness of 3 μm to 15 μm.

13. The ion sensor according to the above 11, wherein the thickness of the ion selective layer is 5 μm to 30 μm.

14. The ion sensor according to 1 above, wherein the electron transport layer entirely surrounds a side surface of the conductive layer.

15. The ion sensor according to 1 above, wherein the ion-selective layer entirely surrounds a side surface of the conductive layer and a side surface of the electron transport layer.

The ion sensor according to embodiments of the present invention includes a substrate, a working electrode disposed on the substrate and including a conductive layer, an electron transport layer and an ion selective layer, and a reference electrode disposed on the substrate spaced apart from the working electrode include Accordingly, it is possible to provide an ion sensor having a small error with respect to a measurement value and improved sensing performance.

As the working electrode includes the ion-selective layer, it may have high selectivity for a specific ion, and the sensing sensitivity and speed may be improved.

In addition, as the electron transport layer includes the metal complex compound, electron and hole transport capability may be improved, and measurement dispersion may be reduced to improve reliability and accuracy of measurement. In addition, as the electron transport layer includes the conductive binder, the metal complex may be uniformly dispersed and fixed in the electron transport layer. Accordingly, the metal complex may be included in a high concentration in the electron transport layer.

In addition, as the electron transport layer including the conductive binder is interposed between the conductive layer and the ion-selective layer, the adhesion of the ion-selective layer and the durability of the ion sensor may increase.

1 is a schematic plan view illustrating an ion sensor according to exemplary embodiments.

2 to 4 are schematic cross-sectional views for explaining an ion sensor according to example embodiments.

5 is a concentration-potential graph of an electrolyte sample measured by an ion sensor according to Examples and Comparative Examples of the present application.

An ion sensor according to embodiments of the present invention includes a substrate, a working electrode disposed on the substrate, and a reference electrode disposed on the substrate to be spaced apart from the working electrode, wherein the working electrode is a conductive electrode disposed on an upper surface of the substrate. a layer, an electron transport layer disposed on the upper surface of the conductive layer and including a conductive binder and a metal complex, and an ion selective layer disposed on the upper surface of the electron transport layer. By dispersing and fixing the metal complex in the electron transport layer, it is possible to improve the sensing performance of the sensing target material.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is described in such drawings It should not be construed as being limited only to the matters.

1 is a schematic plan view of an ion sensor according to exemplary embodiments.

Referring to FIG. 1 , an ion sensor according to example embodiments includes a substrate 100 , a working electrode 210 , a reference electrode 220 , and a wiring 310 . In addition, an auxiliary sensor 320 may be further included.

The substrate 100 may be provided as a substrate on which the working electrode 210 , the reference electrode 220 , the wiring 310 , and the like are disposed.

For example, the substrate 100 may be a commonly used substrate or film material without any particular limitation, and may include, for example, glass, a polymer, and/or an inorganic insulating material.

Preferably, the substrate 100 may be a film having flexible properties. For example, the film may include a polyester-based resin such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose resins, such as a diacetyl cellulose and a triacetyl cellulose; polycarbonate-based resin; acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrenic resins such as polystyrene and acrylonitrile-styrene copolymer; polyolefin-based resins such as polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, and an ethylene-propylene copolymer; vinyl chloride-based resin; amide-based resins such as nylon and aromatic polyamide; imide-based resin; polyether sulfone-based resin; sulfone-based resins; polyether ether ketone resin; sulfide polyphenylene-based resin; vinyl alcohol-based resin; vinylidene chloride-based resin; vinyl butyral-based resin; allylate-based resin; polyoxymethylene-based resins; and a film composed of a thermoplastic resin such as an epoxy-based resin, and a film composed of a blend of the above-mentioned thermoplastic resins can also be used. In addition, a film made of a thermosetting resin or ultraviolet curable resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone may be used.

In some embodiments, the thickness of the substrate 100 may be 1 μm to 500 μm. Within the thickness range, the strength, handleability, workability, and thinness of the ion sensor may be excellent. Preferably it may be 1㎛ to 300㎛, more preferably 5㎛ to 200㎛.

For example, the substrate 100 may contain one or more additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like.

In some embodiments, the substrate 100 may include various functional layers such as a hard coating layer, an anti-reflection layer, and a gas barrier layer on one or both sides of the film.

In some embodiments, the substrate 100 may be surface-treated. For example, the surface treatment may include a plasma treatment, a corona treatment, a dry treatment such as a primer treatment, and a chemical treatment such as an alkali treatment including a saponification treatment.

2 to 4 are schematic cross-sectional views of ion sensors according to exemplary embodiments.

2 to 4 , the working electrode 210 includes a first conductive layer 212 , an electron transport layer 214 , and an ion selective layer 216 .

The working electrode 210 includes a first conductive layer 212 , an electron transport layer 214 disposed on the top surface of the first conductive layer 212 , and an ion selective layer ( 216) may be included. The working electrode 210 may detect an electrical signal generated by a reaction between the ion-sensitive material of the ion-selective layer 216 and the sensing target material. For example, the sensing target material may be an ion or a molecule.

The first conductive layer 212 may be disposed on the substrate 100 . For example, the first conductive layer 212 may directly contact the substrate 100 . The first conductive layer 212 may serve as a path through which electrons and/or holes generated in reaction with a sensing target material are transmitted.

Referring to FIG. 3 , the first conductive layer 212 may include a metal layer 212a and a metal protection layer 212b.

The metal protective layer 212b may entirely cover the upper surface of the metal layer 212a. For example, the metal protective layer 212b may be in direct contact with the metal layer 212a. The metal protective layer 212b may prevent the metal layer 212a from directly contacting the outside, thereby preventing oxidation-reduction of the metal layer 212a.

In some embodiments, the metal layer 212a may include at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof. For example, an APC (Ag-Pd-Cu) alloy may be used. The metal layer 212a may be formed of at least one of Au, Ag, APC alloy, and Pt. The Au, Ag, APC alloy, and Pt may improve electrical conductivity and reduce resistance of the first conductive layer 212 . Therefore, the detection performance of the ion sensor can be improved.

In some embodiments, the thickness of the metal layer 212a may be 500 Å to 4000 Å. Detection performance may be excellent within the thickness range. Preferably, the thickness of the metal layer 212a may be 1000 Å to 3000 Å.

In some embodiments, the metal protective layer 212b may include a transparent conductive oxide. For example, the metal protective layer 212b is a transparent conductive oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (Zinc oxide, ZnO), and indium zinc tin. Oxide (Indium Zinc Tin Oxide, IZTO), cadmium tin oxide (Cadmium Tin Oxide, CTO) 　 may include, preferably ITO or IZO. In some embodiments, the metal protective layer 212b may be formed of only ITO or IZO. ITO and IZO are chemically stable while having electrical conductivity, so that the metal layer 212a can be effectively protected from oxidation-reduction reactions.

For example, the metal protective layer 212b may prevent the metal layer 212a from coming into direct contact with the atmosphere or a sample to prevent oxidation of a metal component constituting the metal layer 212a. Accordingly, the reliability of the electrical signal sensed by the metal layer 212a may be improved.

In some embodiments, the thickness of the metal passivation layer 212b may be 100 Å to 800 Å. The metal layer 212a may be effectively protected within the thickness range, and electrical conductivity of the first conductive layer 212 may be improved. Preferably, the thickness of the metal protective layer 212b may be 300 Å to 500 Å.

The electron transport layer 214 may be disposed on the upper surface of the first conductive layer 212 . For example, the upper surface and side surfaces of the first conductive layer 212 may be covered. In this case, direct contact between the first conductive layer 212 and the outside may be prevented, and corrosion or oxidation of the first conductive layer 212 may be suppressed by the electron transport layer 214 .

The electron transport layer 214 may include a conductive binder and a metal complex. The electron transport layer 214 may rapidly transport electrons and/or holes generated in the ion-selective layer 216 to the first conductive layer 212 to improve sensing performance of the sensing target material of the ion-selective layer 216 . can

For example, in the ion selective layer 216 , electrons/holes may be generated by a reaction between the ion-sensitive material and the sensing target material, and the metal complex compound is a material that is oxidized or reduced by receiving electrons/holes generated by the reaction. may include Accordingly, electrons/holes may be transferred to the first conductive layer 212 through the oxidation or reduction.

In measuring the sensing target material through the ion sensor, a potential difference generated by a difference in concentration of the sensing target material inside/outside the working electrode 210 may be used. In this case, the electromotive force generated in the ion-selective layer 216 may change depending on the transport state of electrons and/or holes, and accordingly, the distribution of the potential difference value between the working electrode 210 and the reference electrode 220 may increase. can

For example, since electron/hole transport is unstable, a voltage according to the concentration of a sensing target material may not be constantly maintained, and an error may occur in measuring a potential difference. In this case, the dispersion of the potential difference value may increase during repeated measurement due to the non-uniform potential difference, and the measured potential difference value may vary even when samples of the same concentration are measured. Also, minute changes in ion concentration may not be detected.

In the ion sensor according to exemplary embodiments, as the electron transport layer 214 including the metal complex is disposed between the first conductive layer 212 and the ion selective layer 216 , the ion selective layer 216 generates The voltage can be kept stable. Accordingly, the potential difference measured between the working electrode 210 and the reference electrode 220 may be constantly maintained according to the concentration of the sensing target material, and the accuracy and reliability of the measured value through the ion sensor may be improved.

For example, since the metal complex has abundant electron density and excellent oxidation-reduction reaction characteristics, electrons and/or holes generated from the ion selective layer 216 may be efficiently transported to the first conductive layer 212 . Accordingly, in measuring the potential difference between the working electrode 210 and the reference electrode 220 , a measurement speed for a threshold value may be improved, and dispersion of an electrical signal measured from the ion sensor may be reduced.

In some embodiments, the metal complex compound is a cyano group (CN) containing compound such as Prussian blue, potassium ferricyanide, potassium ferrocyanide; Hexaammineruthenium (III) chloride; Ferrocene-based compounds; Quinone-based compounds such as 1,2-benzoquinone, 1,4-benzoquinone, 1,4-naphthoquinone, and anthraquinone; Or it may include a hydroquinone-based compound and the like.

Preferably, the metal complex compound may include a cyano group (CN)-containing compound such as Prussian blue, potassium ferricyanide and potassium ferrocyanide.

The cyano group-containing compound can be easily oxidized or reduced. Accordingly, electrons and holes may be easily and quickly transported, and a potential difference between the working electrode 210 and the reference electrode 220 may be stably maintained.

More preferably, the metal complex may include Prussian blue. For example, Prussian blue is a blue pigment containing ferric (III) hexacyanoferrate (II) potassium as a main component, and may have high oxidation properties. As the electron transport layer 214 including Prussian blue is disposed on the first conductive layer 212 , the electrical sensitivity of the working electrode 210 may be improved, and measurement dispersion may be improved.

In some embodiments, the metal complex compound may be included in an amount of 0.01 wt% to 10 wt% based on the total weight of the electron transport layer 214 . When the content of the metal complex is less than 0.01 wt %, a path through which electrons/holes move to the first conductive layer 212 may not be sufficiently secured, and dispersion of the measured values may increase. When the content of the metal complex compound is greater than 10% by weight, the surface of the conductive binder may be modified as the content of the metal complex compound compared to the conductive binder increases, and the measurement dispersion may increase.

Preferably, the metal complex may be included in an amount of 0.1 wt% to 7 wt%, more preferably 0.5 wt% to 3 wt%, based on the total weight of the electron transport layer 214. Within the above range, excellent electron transport capability may be secured, and accuracy and reliability of the measured voltage or potential difference may be improved.

Since the electron transport layer 214 includes the conductive binder, it is possible to prevent the ion selective layer 216 from being peeled off from the working electrode 210 .

For example, when the ion-selective layer 216 is directly laminated on the first conductive layer 212 , the ion-selective layer 216 selects ions during the measurement process due to the low adhesion of the ion-selective layer 216 to the first conductive layer 212 . Delamination of the stratified layer 216 may occur.

According to exemplary embodiments, as an electron transport layer 214 comprising a conductive binder is disposed between the first conductive layer 212 and the ion selective layer 216 , each structure/ Adhesion and adhesion between the layers may be improved. Accordingly, durability and mechanical/chemical stability of the ion sensor may be improved.

In some embodiments, the conductive binder may include a carbon paste, a metal-containing paste, and a conductive polymer.

For example, the carbon paste may include carbon black, graphite, graphite oxide, graphene, graphene oxide, and the like. For example, the metal-containing paste may include Cu, Ag, Au, Ni, Pa, Pt, and the like, and preferably Ag/AgCl paste. For example, the conductive polymer may be poly(3,4-ethylenedioxythiophenes)), poly(styrene sulfonates), PEDOT:PSS(Poly( 3,4-ethylenedioxythiophenes):poly(styrenesulfonates)) and the like.

Preferably, the conductive binder may include a carbon paste in consideration of electron and/or hole transport characteristics, adhesion, durability, and the like.

According to exemplary embodiments, the thickness of the electron transport layer 214 may be 3 μm to 15 μm, preferably 5 μm to 10 μm. When the thickness is less than 3 μm, the adhesion between the first conductive layer 212 , the electron transport layer 214 , and the ion selective layer 216 may decrease. When the thickness is greater than 15 μm, sensing sensitivity and speed may decrease, and dispersion of measured values may increase.

The ion selective layer 216 may be disposed on the upper surface of the electron transport layer 214 . For example, the ion selective layer 216 may cover the top and side surfaces of the electron transport layer 214 . For example, the ion selective layer 216 may cover the side surface of the first conductive layer 212 and the top and side surfaces of the electron transport layer 214 .

Referring to FIG. 4 , the electron transport layer 214 may entirely cover the top and side surfaces of the first conductive layer 212 , and the ion selective layer 216 may entirely cover the top and side surfaces of the electron transport layer 214 . can

Accordingly, it is possible to prevent the measurement target sample from directly contacting the electron transport layer 214 and the first conductive layer 212 , and it is possible to improve the accuracy of the measurement value according to the concentration of the sensing target material.

The ion-selective layer 216 may include an ion-sensitive material and a polymer support. The ion selective layer 216 may generate a potential difference between the working electrode 210 and the reference electrode 220 by directly contacting the measurement sample to sense the sensing target material.

The ion-sensitive material may serve to impart selectivity to a specific ion and generate a voltage by reacting with the ion. For example, the ion-sensitive material may be a material that causes a covalent bond, a coordination bond, or an ion exchange reaction with a sensing target material (eg, ion) included in the measurement sample.

The ion-sensitive material may be selected according to the ion to be measured. For example, the ion sensor may selectively detect specific ions by changing the ion-sensitive material included in the ion-selective layer 216 .

Examples of the ions to be measured include H ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , OH ^- , Cl ^- , F ^- , Br ^- , I ^- , CN ^- and NO ₃ ^- . However, the present invention is not limited thereto, and various measurement target ions may be selected as needed.

For example, the ion-sensitive material is at least one of H ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , OH ^- , Cl ^- , F ^- , Br ^- , I ^- , CN ^- and NO ₃ ^- It may include a material that selectively sensitizes the ions of the ion-selective layer 216 and transmits them into the ion-selective layer 216 .

For example, as the ion-sensitive substance, N,N',N"-tripeptyl-N,N',N"-trimethyl-4,4',4"-propyridinetris(3-oxabutylamide) (N ,N',N''-Triheptyl-N,N',N''-trimethyl-4,4',4''-propylidynetris(3-oxabutyramide)), N,N'-dibenzyl-N,N' -diphenyl-1,2-phenylenediacetamide (N,N'-Dibenzyl-N,N'-diphenyl-1,2-phenylenedioxydi-acetamide), N,N,N',N'-tetracyclohexyl -1,2-phenylenedioxydiacetamide (N,N,N',N'-Tetracyclohexyl-1,2-phenylenedioxydiacetamide), 2,3:11,12-didecalino-16-crown-5 (2 ,3:11,12-Didecalino-16-crown-5), 4-octadecanoyloxymethyl-N,N,N',N'-tetracyclohexyl-1,2-petylenedioxydiacetamide ( 4-Octadecanoyloxymethyl-N,N,N',N'-tetracyclohexyl-1,2-phenylenedioxydiacetamide), (-)-(R,R)-N'N'-bis[(11-ethoxycarbonyl)undecyl ]-N'N"4,5-tetramethyl-3,6-dioxaoctane-diamide ((-)-(R,R)-N'N'-Bis-[11-(ethoxycarbonyl)undecyl]- N'N",4,5-tetramethyl-3,6-dioxaoctanediamide), bis[(12-crown-4)methyl]dodecylmethylmalonate (Bis[(12-crown-4)methyl] dodecylmethylmalonate), 4 -t-Butylcalix[4]arene-tetraacetic acid tetraethyl ester (4-tert-Butylcalix[4]arene-tetraacetic acid tetraethylester), Maduramicin, Valinomycin, Salinomycin ( Salinomycin), Beauvericin, Nonactin, Monensin, (4S)-4-methyl-salinomycin ((4) S)-4-methyl-salinomycin) bis[(12-crown-4)methyl] 2,2-didodecylmalonate (Bis[(12-crown-4)methyl] 2,2-didodecylmalonate), dicyclohexyl 18-crown-6 (Dicyclohexyl 18-crown-6), Nafto-15-crown-5, Bis (15-crown-5) (Bis (15-crown-5), etc. and crown ether compounds of

As the ion-selective layer 216 includes an ion-sensitive material, a sensing target material (eg, a measurement target ion) may be selectively transmitted. Accordingly, a concentration difference of the sensing target material may occur inside and outside the working electrode 210 with the ion selective layer 216 as a boundary. For example, the concentration of the sensing target material outside the working electrode 210 may be lower than the concentration of the sensing target material inside the working electrode 210 .

In this case, an electromotive force is generated by the concentration difference of the sensing target material inside/outside the working electrode 210 , and thus a potential difference between the working electrode 210 and the reference electrode 220 may occur. For example, the potential of the working electrode 210 may change in proportion to the concentration of the sensing target material included in the sample. Accordingly, the potential difference between the working electrode 210 and the reference electrode 220 according to the concentration of the sensing target material may be measured by using the reference electrode 220 having a constant potential as a counter electrode. By measuring the potential difference, the concentration of the sensing target material in the sample may be measured.

In some embodiments, the ion-sensitive material may be included in an amount of 0.5% to 10% by weight of the total weight of the ion-selective layer 216 . If it is less than 0.5% by weight, the sensitivity and selectivity to the sensing target material may be reduced, and if it is more than 10% by weight, the content of the polymer support may be relatively decreased, resulting in deterioration in stability and adhesion.

The polymer support forms the structure/appearance of the ion-selective layer 216 , and may serve to fix the ion-sensitive material in the ion-selective layer 216 .

According to exemplary embodiments, the polymer support is polyvinyl chloride (PVC), polyvinyl chloride carboxylate (Polyvinyl chloride carboxylate), polyvinyl chloride aminate (Polyvinyl chloride aminate), polymethyl acrylate (Poly ( methylacrylate)), polyethylene oxide (Poly(ethylene oxide)), Xerogel, Polyurethane, Silicone rubber, Agarose, Polyvinyl butyral (PVB) And polyvinyl alcohol (Polyvinyl alcohol, PVA) and the like.

In some embodiments, the polymer support may be included in an amount of about 20% to 40% by weight based on the total weight of the ion selective layer 216 . Structural stability may be improved while preventing an increase in resistance within the above range.

In some embodiments, the ion selective layer 216 may further include a plasticizer. As the ion-selective layer 216 includes a plasticizer, flexibility may be improved, and deterioration of signal stability due to high resistance may be prevented. For example, as the electrical resistance of the ion-selective layer 216 decreases, charge separation formed on the surface of the membrane by bonding with specific ions or molecules may easily occur. Accordingly, an ion sensor having a stable signal and a fast response time may be provided.

For example, as a plasticizer, 2-nitrophenyl octyl ether (NPOE), dioctyl sebacate (DOS), bis (2-ethylhexyl) phthalate (Bis (2-ethylhexyl) phthalate) , DOP), bis (2-ethylhexyl) adipate (Bis (2-ethylhexyl) adipate, DOA), 2-nitrophenyl octyl ether (NPOE), diethyl succinate, and dioctyl maleate and diundecyl phthalate.

In some embodiments, the plasticizer may be included in an amount of about 50 wt% to about 80 wt% of the total weight of the ion selective layer 216 . Structural stability of the ion-selective layer 216 may be improved while preventing an increase in resistance within the above range.

In example embodiments, the thickness of the ion-selective layer 216 may be greater than the thickness of the electron transport layer 214 . For example, the thickness of the ion selective layer 216 may be 5 μm to 30 μm, preferably 15 μm to 20 μm. Within the above range, the sensing sensitivity and speed may be excellent while improving the selectivity and sensitivity to the sensing target material.

According to exemplary embodiments, a first conductive layer 212 is formed on the substrate 100 , an electron transport layer 214 is formed on the first conductive layer 212 , and an electron transport layer 214 is formed on the substrate 100 . By forming the ion-selective layer 216 thereon, the working electrode 210 can be manufactured.

The first conductive layer 212 is formed on the substrate 100 with a metal film including at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof, and then It may be formed by patterning.

For the patterning, a patterning method commonly used in the art may be used. For example, photolithography may be used.

When the first conductive layer 212 further includes a metal protective layer 212b, the metal layer 212a is first patterned and then the metal protective layer 212b is formed, or a transparent conductive oxide film is formed on the metal layer. Then, the metal layer and the transparent conductive oxide layer may be patterned together to form the metal layer 212a and the metal protective layer 212b together.

In some embodiments, the electron transport layer 214 may be formed by coating a mixture of a conductive binder and a metal complex on the first conductive layer 212 and then drying the mixture. For the application, a coating method commonly used in the art may be used, for example, various printing methods may be used.

In some embodiments, the ion selective layer 216 may be formed by applying a mixture of a polymer support and an ion-sensitive material, or a mixture of a polymer support, an ion-sensitive material, and a plasticizer on the electron transport layer 214 and then drying. can

The reference electrode 220 may be disposed on the substrate 100 . For example, the reference electrode 220 may be disposed on the same plane as the working electrode 210 of the substrate 100 . For example, the reference electrode 220 may be disposed to be spaced apart from the working electrode 210 , and the reference electrode 220 and the working electrode 210 may be electrically insulated.

The reference electrode 220 may provide a reference value for a voltage value or a potential value measured by the working electrode 210 when measuring a sample. By using the potential value of the reference electrode 220 as a reference value, the concentration of the sensing target material selectively transmitted into the working electrode 210 may be specified.

For example, by comparing the potential value at the reference electrode 220 with the potential value measured at the working electrode 210 , the sensing target material (eg, specific ion) inside/outside the working electrode 210 . It is possible to calculate the voltage generated by the concentration difference of , and it is possible to derive the concentration of the component to be measured from the voltage.

In some embodiments, the reference electrode 220 may include a second conductive layer 222 and a reference material layer 224 . For example, the second conductive layer 222 may be disposed on the upper surface of the substrate 100 , and the reference material layer 224 may be disposed on the upper surface of the second conductive layer 222 .

For example, the second conductive layer 222 of the reference electrode 220 may include substantially the same material as the first conductive layer 212 of the working electrode 210 . For example, the reference material layer 224 may include Ag/AgCl paste.

In some embodiments, the reference electrode 220 may include an Ag/AgCl electrode layer. For example, the Ag/AgCl electrode layer may be formed from Ag/AgCl paste, and the Ag/AgCl electrode layer may be disposed on the substrate 100 to directly contact the Ag/AgCl electrode layer.

In some embodiments, the wiring 310 may be connected to each of the working electrode 210 and the reference electrode 220 . The wiring 310 connected to the working electrode 210 and the wiring 310 connected to the reference electrode 220 may be electrically insulated from each other.

For example, the wiring 310 may be formed of the same material as the first conductive layer 212 of the working electrode 210 , and may be formed of the same material as the second conductive layer 222 of the reference electrode 220 . can

In some embodiments, the wiring 310 may be integrally formed with the working electrode 210 and the reference electrode 220 . The wiring 310 may be integrally formed by forming a metal film on the substrate 100 and patterning it. Alternatively, the first conductive layer 212 , the reference electrode 220 , and the wiring 310 may be integrally formed through a screen printing method.

In some embodiments, the wire 310 connected to the working electrode 210 and the wire 310 connected to the reference electrode 220 may be connected to the sensing driver.

Accordingly, an electrical signal (eg, a potential difference) measured from the working electrode 210 and the reference electrode 220 may be transmitted to the sensing driver through the wiring 310 . For example, the sensing driver may be a driving integrated circuit (IC) chip, and the concentration of the sensing target material may be calculated by the driving IC chip.

For example, the sensing driver may include a signal detector and a signal processor. The signal sensing unit and the signal processing unit may be electrically connected to each other.

The signal detector may detect a potential difference between the working electrode 210 and the reference electrode 220 according to the concentration of the sensing target material. The signal processing unit may calculate the concentration of the sensing target material from the potential difference between the working electrode 210 and the reference electrode 220 measured by the signal sensing unit.

In some embodiments, the ion sensor may further include an auxiliary sensor 320 . The auxiliary sensor 320 may be electrically connected to the wiring 310 , and may correct a measurement deviation according to a surrounding environment. For example, the auxiliary sensor 320 may be a temperature sensor, and may correct a deviation of a measured value according to temperature.

Hereinafter, experimental examples including specific examples and comparative examples are presented to help the understanding of the present invention, but these are merely illustrative of the present invention and do not limit the appended claims, the scope and description of the present invention It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope of the spirit, and it is natural that such variations and modifications fall within the scope of the appended claims.

Examples and Comparative Examples

Example 1

A PET film having a thickness of 180 μm was prepared as a substrate. Thereafter, an APC metal film having a thickness of about 2000 Å and an IZO metal protective film having a thickness of about 500 Å were sequentially applied on the substrate, and then patterned to form a metal layer and a metal protective layer.

Thereafter, a carbon paste containing 0.5% by weight of Prussian blue was screen-printed on the metal protective layer to form an electron transport layer having a thickness of about 8 μm.

After formation of the electron transport layer, 5 wt% of bis[(12-crown-4)methyl]dodecylmethylmalonate (Bis[(12-crown-4)methyl] dodecylmethylmalonate), 35 wt% of polyurethane (PU) and 60% by weight of dioctyl sebacate (DOS) was diluted in 0.4 ml tetrahydrofuran solvent, and then the solution was drop-coated on the electron transport layer. Thereafter, it was dried at room temperature for about 24 hours to form an ion selective layer with a thickness of about 15 μm to form a working electrode.

A reference electrode was formed by screen-printing Ag/AgCl (DBS-4585V, manufactured by Daejoo Electronic Materials) on the substrate to be spaced apart from the working electrode.

Example 2

In Example 1, in the same manner as in Example 1, except that the electron transport layer was formed using a carbon paste containing 3% by weight of Prussian blue instead of the carbon paste containing 0.5% by weight of Prussian blue. An ion sensor was fabricated.

Example 3

In Example 1, in the same manner as in Example 1, except that the electron transport layer was formed using a carbon paste containing 10% by weight of Prussian blue instead of the carbon paste containing 0.5% by weight of Prussian blue. An ion sensor was fabricated.

comparative example

A PET film having a thickness of 180 μm was prepared as a substrate. Thereafter, an APC metal film with a thickness of about 2000 Å and an IZO metal protective film with a thickness of about 500 Å were sequentially applied on the substrate, and then patterned to form a metal layer and a metal protective layer.

After formation of the metal layer and the metal protective layer, a mixture comprising 5 wt% of bis[(12-crown-4)methyl]dodecylmethylmalonate, 35 wt% PU and 60 wt% DOS was mixed with 0.4 ml tetrahydrofuran After dilution in a solvent, the solution was drop-coated on the metal protective layer. Thereafter, it was dried at room temperature for about 24 hours to form an ion selective layer with a thickness of about 15 μm to form a working electrode.

A reference electrode was formed by screen-printing Ag/AgCl (DBS-4585V, manufactured by Daejoo Electronic Materials) on the substrate to be spaced apart from the working electrode.

Experimental Example: Potential difference distribution evaluation

The potential difference in the sodium electrolyte solution was measured using the sensors of Examples and Comparative Examples.

Each electrolyte solution (0.2, 0.5, 0.8, 1.0%) was evenly dropped on the working electrode and the reference electrode, and the potential difference between the working electrode and the reference electrode after 60 seconds at a current density of 3 kA/m ² was measured through the constant current time potentiation method. measured. After measuring the potential difference 5 times for each concentration, the relative standard deviation (RSD) was calculated from the measured potential difference values and shown in Table 1 below.

division	RSD (%)
Electrolyte concentration (%)	Example 1	Example 2	Example 3	comparative example
0.2	One	4	19	38
0.5	0	7	15	52
0.8	One	5	20	55
1.0	One	8	18	54

Referring to Table 1, it can be seen that the relative standard deviation of the measured potential difference value is remarkably low in the examples in which the electron transport layer is interposed between the conductive layer and the ion selective layer.

In the case of the comparative example, as the electron transport layer is not interposed between the conductive layer and the ion selective layer, it can be seen that the value of the relative standard deviation of the measured value is significantly increased compared to that of the Examples.

In addition, the graph of FIG. 5 was obtained through the measured potential difference values of Examples and Comparative Examples. As the distribution in the y-axis direction (Potential) is wider, it indicates that the measurement distribution is deteriorated.

Referring to FIG. 5 , it can be confirmed that the ion sensor of Example 1 has excellent measurement dispersion by stably maintaining the potential value. It can be seen that the ion sensor of the comparative example is not clearly differentiated according to the concentration of the electrolyte solution as the dispersion of the measured values is large.

Claims (15)

1. Board;

   disposed on the substrate,

   a conductive layer disposed on the upper surface of the substrate;

   an electron transport layer disposed on the upper surface of the conductive layer and including a conductive binder and a metal complex dispersed in the conductive binder; and

   a working electrode including an ion-selective layer disposed on an upper surface of the electron transport layer; and

   and a reference electrode disposed on the substrate to be spaced apart from the working electrode.
2. The ion sensor of claim 1 , wherein the conductive layer comprises a metal layer and a metal protective layer disposed on an upper surface of the metal layer.
3. The ion sensor of claim 2 , wherein the metal layer comprises at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof.
4. The ion sensor of claim 2 , wherein the metal protective layer comprises a transparent conductive oxide.
5. The ion sensor according to claim 1, wherein the conductive binder includes a carbon paste, a metal-containing paste, or a conductive polymer.
6. The method according to claim 1, wherein the metal complex is Prussian blue (Prussian blue), potassium ferricyanide (Potassium ferricyanide), potassium ferrocyanide (Potassium ferrocyanide), hexaamine ruthenium (III) chloride (Hexaammineruthenium (III) chloride), ferrocene An ion sensor comprising at least one selected from the group consisting of a compound-based compound, a quinone-based compound, and a hydroquinone-based compound.
7. The ion sensor according to claim 1, wherein the metal complex is included in an amount of 0.01 wt% to 10 wt% of the total weight of the electron transport layer.
8. The ion sensor of claim 1 , wherein the ion-selective layer comprises an ion-sensitive material and a polymer support.
9. The method according to claim 8, wherein the ion-sensitive material is H ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , OH ^- , Cl ^- , F ^- , Br ^- , I ^- , CN ^- and NO ₃ ^- consisting of An ion sensor comprising a material that selectively transmits one ion selected from the group.
10. The method according to claim 8, wherein the polymer support is polyvinyl chloride, polyvinyl chloride carboxylate, polyvinyl chloride aminate, polyvinyl butyral, polyvinyl alcohol, polymethyl acrylate, polyethylene oxide, xerogel, agarose, A sensor comprising at least one selected from the group consisting of polyurethane and silicone rubber.
11. The ion sensor according to claim 1, wherein the thickness of the ion-selective layer is thicker than the thickness of the electron transport layer.
12. The ion sensor of claim 11 , wherein the electron transport layer has a thickness of 3 μm to 15 μm.
13. The ion sensor of claim 11 , wherein the ion-selective layer has a thickness of 5 μm to 30 μm.
14. The ion sensor of claim 1 , wherein the electron transport layer entirely surrounds a side surface of the conductive layer.
15. The ion sensor of claim 1 , wherein the ion-selective layer entirely surrounds a side surface of the conductive layer and a side surface of the electron transport layer.

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