An electrochemical sensor and an electrochemical sensing system based on a 1T1C structure

Abstract

The present invention relates to the field of sensor devices, and discloses an electrochemical sensor and an electrochemical sensing system based on a 1T1C structure. Among them, the electrochemical sensor includes: a substrate; a field effect transistor disposed on the substrate; a sensitive electrode existing in the form of an epitaxial gate and electrically connected to the gate; a reference electrode; and a capacitor connected in parallel between the gate and the source of the field effect transistor. The electrochemical sensing system includes: an electrochemical sensor, a voltage driving and current reading unit, and a signal processing unit. In the electrochemical sensor of the present invention, the potential at the interface between the sensitive electrode and the solution is regulated by the parallel capacitance and the bias voltage, which can meet the detection requirements of molecules with different redox potentials. In the electrochemical sensor of the present invention, the sensitive electrode exists in the form of an epitaxial gate. During detection, only the sensitive electrode and the reference electrode are in contact with the solution to be detected, while the field effect transistor is not directly in contact with the solution, which is beneficial to maintaining the stability of the transistor performance.

Description

Technical Field

[0001] The present invention relates to the field of sensor devices, and particularly to an electrochemical sensor and an electrochemical sensing system based on a 1T1C (referring to one transistor and one capacitor in each sensing unit) structure. Background Art

[0002] The continuous monitoring of ions and molecules in a solution environment is of great significance in many fields, such as the detection of sodium, potassium ions, pH, glucose, uric acid, etc. in human body fluids, and the detection of pH, oxygen, etc. in seawater. Electrochemical sensors based on transistors have received increasing attention due to their easy realization of low power consumption, high throughput, and portability. Compared with electrochemical transistors using a solution gate, an epitaxial gate field-effect transistor can separate the detection region from the transistor, making the transistor performance unaffected by the solution, which is a more ideal sensor structure.

[0003] At present, certain achievements have been made in the detection of ions, nucleic acids, proteins, etc. in a solution by an epitaxial gate field-effect transistor. Depending on the material sensitive to the analyte modified on the surface, the epitaxial gate can convert the change in the concentration of the analyte in the solution into a change in the interfacial potential, and then output it as a change in the drain current by the transconductance characteristic of the field-effect transistor. However, it is difficult to extend this epitaxial gate field-effect transistor structure to molecules that require an oxidation-reduction reaction for detection. On the one hand, the oxidation-reduction potentials of different analytes are different, resulting in the need for the gate to adjust its surface potential according to the detection target. On the other hand, in the gate-source loop of the epitaxial gate field-effect transistor, there are three capacitances at "reference electrode|solution", "epitaxial gate|solution", and "between transistor gate|source". Among them, the capacitance value of the interface related to the solution (from dozens to hundreds of microfarads) is much larger than the capacitance value between the transistor gate and source (a few nanofarads). Therefore, most of the externally applied bias voltage between the gate and source is distributed at the "gate-channel", which can regulate the carrier concentration of the semiconductor layer but cannot effectively regulate the interfacial potential of the epitaxial gate, severely limiting the application range of the sensor based on the epitaxial gate field-effect transistor.

[0004] In order to effectively regulate the interfacial potential of the epitaxial gate in the epitaxial gate field-effect transistor, and not limit the application range of the transistor sensor to the detection of charge adsorption-type substances but expand it to the detection of molecules that undergo oxidation-reduction reactions, it is urgent to design and develop a new device structure. Summary of the Invention

[0005] To solve the technical problem that traditional epitaxial-gate field-effect transistors cannot effectively regulate the gate interface potential, severely limiting the application scope of transistor sensors, the present invention provides an electrochemical sensor and an electrochemical sensing system based on a 1T1C structure. The present invention can not only effectively adjust the epitaxial gate interface potential between -1 V and 1 V (relative to the Ag / AgCl reference electrode), but also detect analytes with too high or too low redox potentials based on the adjusted interface potential.

[0006] The specific technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides an electrochemical sensor based on a 1T1C structure, comprising:

[0008] A substrate;

[0009] A field-effect transistor disposed on the substrate; the field-effect transistor includes a gate, a source, and a drain; the field-effect transistor is a transducer of the electrochemical sensor, for converting the change in the interface potential at the sensitive electrode into a change in the output drain current;

[0010] A sensitive electrode existing in the form of an epitaxial gate and electrically connected to the gate; the surface of the sensitive electrode is modified with a material sensitive to the substance to be detected, to achieve the sensing application of the substance to be detected within a specific voltage range; the sensitive electrode is an element sensitive to the substance to be detected, for converting the concentration information of the substance to be detected into interface potential information;

[0011] A reference electrode; the reference electrode is used to maintain a constant potential difference between the electrode and the solution;

[0012] A capacitor connected in parallel between the gate and the source of the field-effect transistor.

[0013] In the electrochemical sensor of the present invention, the sensitive electrode serves as the epitaxial gate of the field-effect transistor. The bias voltage is applied through the first electrical contact terminal (connecting the reference electrode to the voltage driving and current reading unit). During detection, the sensitive electrode and the reference electrode are directly in contact with the solution. The potential at the interface between the sensitive electrode and the solution is not only regulated by the size of the parallel capacitance and the bias voltage, but also has a potential response to the concentration of the analyte. Further, the field-effect transistor converts the potential response of the sensitive electrode to the analyte into a drain current output.

[0014] Preferably, the capacitance value of the capacitor is between 0.1 and 10 times the capacitance value of the interface between the sensitive electrode and the solution to be detected.

[0015] Preferably, the electrochemical sensor based on the 1T1C structure further includes a packaging layer covering the field-effect transistor and the capacitor and only exposing the sensitive electrode and the reference electrode.

[0016] Preferably, the material of the encapsulation layer may be, but is not limited to, polyethylene.

[0017] Preferably, the material of the substrate may be, but is not limited to, non-flexible materials such as PCB boards and silicon wafers, and flexible materials such as polyimide (PI), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET).

[0018] Preferably, the capacitor may be, but is not limited to, an aluminum electrolytic capacitor or a supercapacitor.

[0019] Preferably, the field effect transistor may be, but is not limited to, a metal-oxide-semiconductor field effect transistor (MOSFET), a thin film field effect transistor (TFT), etc.

[0020] Furthermore, the electrochemical sensor based on the 1T1C structure includes:

[0021] A substrate;

[0022] A bottom gate electrode disposed on the upper surface of the substrate;

[0023] A bottom gate insulating layer covering the bottom gate electrode;

[0024] A drain electrode and a source electrode disposed on the surface of the bottom gate insulating layer in the same layer;

[0025] An organic semiconductor layer covering the drain electrode, the source electrode, and the area between the drain electrode and the source electrode on the bottom gate insulating layer;

[0026] A first encapsulation layer covering the semiconductor layer;

[0027] A waterproof layer covering the first encapsulation layer;

[0028] A first electrode, a second electrode, and a third electrode disposed on the surface of the waterproof layer in the same layer;

[0029] A first electrode supercapacitor electrode material layer modified on the surface of the first electrode and a second electrode supercapacitor electrode material layer modified on the upper surface of one end of the second electrode;

[0030] A solid electrolyte layer covering the first electrode supercapacitor electrode material layer, the second electrode supercapacitor electrode material layer, and the area between the two on the waterproof layer;

[0031] A sensitive electrode functionalized modification layer disposed on the upper surface of the other end of the second electrode;

[0032] A reference electrode coating disposed on the upper surface of the third electrode;

[0033] A first via hole connecting the source electrode and the first electrode, and a conductive medium is provided in the first via hole;

[0034] A second via hole connecting the bottom gate electrode and the second electrode, and a conductive medium is provided in the second via hole;

[0035] A second encapsulation layer disposed above the waterproof layer and the solid electrolyte layer, and two via holes exposing the sensitive electrode functionalized modification layer and the reference electrode coating are provided in the second encapsulation layer.

[0036] Preferably, the material of the substrate may be, but is not limited to, non-flexible materials such as PCB boards and silicon wafers, and flexible materials such as polyimide (PI), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET).

[0037] The materials of the bottom gate electrode, drain electrode, source electrode, first electrode, second electrode, third electrode, and the conductive medium in the first via hole / second via hole are all gold, and other inert electrode materials with low chemical reactivity can also be selected according to actual requirements.

[0038] Preferably, the material of the bottom gate insulating layer may be, but is not limited to, polymer materials such as polyvinyl cinnamate (PVCN) or polyvinylidene fluoride (PVDF);

[0039] Preferably, the material of the organic semiconductor layer may be, but is not limited to, organic conductive small molecule materials such as TIPS-pentacene.

[0040] Preferably, the materials of the first encapsulation layer and the second encapsulation layer may be, but is not limited to, polymer materials such as amorphous fluororesin (CYTOP).

[0041] Preferably, the material of the waterproof layer may be, but is not limited to, polymer materials such as phenolic resin and polyimide.

[0042] Preferably, the sensitive electrode functionalized modification layer 231 needs to be selected according to a specific substance to be detected. For example, platinum metal nanoparticles or other metal oxides for detecting glucose, etc.

[0043] Preferably, the type of the field effect transistor may be, but is not limited to, commercially available metal-oxide-semiconductor field effect transistors and thin film transistors. If the substance to be detected needs to adjust the potential at the interface between the sensitive electrode and the solution to a higher value, a p-type transistor is selected; if the substance to be detected needs to adjust the potential at the interface between the sensitive electrode and the solution to a lower value, an n-type transistor is selected.

[0044] Preferably, the reference electrode coating may be, but is not limited to, commercially available standard hydrogen electrode coatings and silver / silver chloride coatings.

[0045] In a second aspect, the present invention provides an electrochemical sensing system, comprising:

[0046] The above-mentioned electrochemical sensor based on the 1T1C structure;

[0047] A voltage driving and current reading unit; the voltage driving and current reading unit is electrically connected to the reference electrode and the source and drain electrodes of the field effect transistor through three electrical contact terminals, and is used to apply voltages to the reference electrode and the source and drain electrodes of the field effect transistor, and at the same time read the output drain current;

[0048] A signal processing unit; the signal processing unit is used to generate a calibration curve of the concentration of the analyte and the output drain current value in the calibration step, and convert the read drain current value into the corresponding concentration information of the analyte according to the calibration curve in the test step.

[0049] Preferably, the electrochemical sensing system further includes a polymer tank for holding the calibration solution and the solution to be detected; the polymer tank surrounds the area where the sensitive electrode and the reference electrode are located.

[0050] Preferably, the material of the polymer tank can be, but is not limited to, polydimethylsiloxane (PDMS), silicone rubber.

[0051] Compared with the prior art, the beneficial effects of the present invention are:

[0052] (1) In the electrochemical sensor of the present invention, the potential at the interface between the sensitive electrode and the solution is regulated by the parallel capacitance and the bias voltage, which can meet the detection requirements of molecules with different redox potentials.

[0053] (2) In the electrochemical sensor of the present invention, the sensitive electrode exists in the form of an epitaxial gate. During detection, only the sensitive electrode and the reference electrode are in contact with the solution to be detected, while the field effect transistor is not directly in contact with the solution, which is beneficial to maintaining the stability of the transistor performance. In addition, a waterproof layer is also provided in the electrochemical sensor of the present invention, which can further ensure that the device is not affected by the solution.

[0054] (3) The electrochemical sensor of the present invention has a simple structure and is convenient for array integration. Description of the Drawings

[0055] Figure 1 is a schematic structural diagram of the electrochemical sensor using an organic thin film transistor (OTFT) and a solid-state supercapacitor in Embodiment 1 of the present invention;

[0056] Figure 2 is a schematic structural diagram of the electrochemical sensing system based on the 1T1C structure in Embodiment 2 of the present invention;

[0057] Figure 3It is the influence of the size of the parallel aluminum electrolytic capacitor on the transfer characteristic curve of the p-type MOSFET in a preferred embodiment of the present invention;

[0058] Figure 4 It is the regulation curve of the interface potential between the epitaxial gate and the solution by the size of the parallel aluminum electrolytic capacitor when using a p-type MOSFET in a preferred embodiment of the present invention;

[0059] Figure 5 It is the detection effect of the sensor on glucose after the interface potential between the epitaxial gate and the solution is increased when using a p-type MOSFET and an aluminum electrolytic capacitor in a preferred embodiment of the present invention;

[0060] Figure 6 It is the regulation curve of the interface potential between the epitaxial gate and the solution by the size of the parallel aluminum electrolytic capacitor when using an n-type MOSFET in a preferred embodiment of the present invention;

[0061] Figure 7 It is the detection effect of the sensor on oxygen after the interface potential between the epitaxial gate and the solution is decreased when using an n-type MOSFET and an aluminum electrolytic capacitor in a preferred embodiment of the present invention.

[0062] The reference numerals of the drawings are: substrate 0, sensitive electrode 1, reference electrode 2, field effect transistor 4, capacitor 3, voltage driving and current reading module 5, signal processing module 6, polymer tank 7, organic thin film transistor 11, solid-state super capacitor 12, bottom gate electrode 111, bottom gate insulating layer 112, drain 113, source 114, organic semiconductor layer 115, first encapsulation layer 116, waterproof layer 117, first electrode 121, first electrode super capacitor electrode material layer 122, second electrode 123, second electrode super capacitor electrode material layer 124, solid electrolyte layer 125, sensitive electrode functionalized modification layer 131, third electrode 141, silver / silver chloride layer 142, first through hole 151, second through hole 161, second encapsulation layer 171. Detailed Embodiments

[0063] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0064] In the drawings, components with the same structure are denoted by the same numerals, and components with similar structures or functions are denoted by similar numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. To make the illustration clearer, the thickness of some parts in the drawings is appropriately exaggerated.

[0065] General Embodiment

[0066] An electrochemical sensor based on a 1T1C structure, comprising:

[0067] A substrate; the material of the substrate can be, but is not limited to, non-flexible materials such as PCB boards and silicon wafers, and flexible materials such as polyimide (PI), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET);

[0068] A field-effect transistor disposed on the substrate; the field-effect transistor includes a gate, a source, and a drain; the field-effect transistor is a transducer device of the electrochemical sensor, and is used to convert the change in the interfacial potential at the sensitive electrode into a change in the output drain current; the field-effect transistor can be, but is not limited to, a metal-oxide-semiconductor field-effect transistor (MOSFET), a thin-film field-effect transistor (TFT), etc.;

[0069] A sensitive electrode existing in the form of an epitaxial gate and electrically connected to the gate; the surface of the sensitive electrode is modified with a material sensitive to the substance to be detected, so as to realize the sensing application of the substance to be detected within a specific voltage range; the sensitive electrode is a component sensitive to the substance to be detected, and is used to convert the concentration information of the substance to be detected into interfacial potential information;

[0070] A reference electrode; the reference electrode is used to maintain a constant potential difference between the electrode and the solution;

[0071] A capacitor connected in parallel between the gate and the source of the field-effect transistor. The capacitance value of the capacitor is between 0.1 and 10 times the capacitance value of the interface between the sensitive electrode and the solution to be detected; the capacitor can be, but is not limited to, an aluminum electrolytic capacitor, a supercapacitor;

[0072] A packaging layer covering the field-effect transistor and the capacitor and only exposing the sensitive electrode and the reference electrode. The material of the packaging layer can be, but is not limited to, polyethylene.

[0073] Furthermore, the electrochemical sensor based on the 1T1C structure specifically includes:

[0074] A substrate;

[0075] A bottom gate electrode disposed on the upper surface of the substrate;

[0076] A bottom gate insulating layer covering the bottom gate electrode;

[0077] A drain and a source disposed on the surface of the bottom gate insulating layer in the same layer;

[0078] An organic semiconductor layer covering the drain, the source, and the region between the drain and the source of the bottom gate insulating layer;

[0079] A first encapsulation layer covering the semiconductor layer;

[0080] A waterproof layer covering the first encapsulation layer;

[0081] A first electrode, a second electrode, and a third electrode disposed on the surface of the waterproof layer in the same layer;

[0082] A first electrode supercapacitor electrode material layer modified on the surface of the first electrode and a second electrode supercapacitor electrode material layer modified on the upper surface of one end of the second electrode;

[0083] A solid electrolyte layer covering the first electrode supercapacitor electrode material layer, the second electrode supercapacitor electrode material layer, and the waterproof layer in the region between the two;

[0084] A sensitive electrode functionalized modification layer disposed on the upper surface of the other end of the second electrode;

[0085] A reference electrode coating disposed on the upper surface of the third electrode;

[0086] A first through hole connecting the source electrode and the first electrode, and a conductive medium is provided in the first through hole;

[0087] A second through hole connecting the bottom gate electrode and the second electrode, and a conductive medium is provided in the second through hole;

[0088] A second encapsulation layer disposed above the waterproof layer and the solid electrolyte layer, and two through holes exposing the sensitive electrode functionalized modification layer and the reference electrode coating are provided in the second encapsulation layer.

[0089] Preferably, the material of the substrate may be, but is not limited to, non-flexible materials such as PCB boards and silicon wafers, and flexible materials such as polyimide (PI), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET); the materials of the bottom gate electrode, drain, source, first electrode, second electrode, third electrode, and the conductive medium in the first via / second via are all gold, and other inert electrode materials with low chemical reactivity can also be selected according to actual requirements; the material of the bottom gate insulating layer may be, but is not limited to, polymer materials such as polyvinyl cinnamate (PVCN) or polyvinylidene fluoride (PVDF); the material of the organic semiconductor layer may be, but is not limited to, organic conductive small molecule materials such as TIPS-pentacene. The materials of the first encapsulation layer and the second encapsulation layer may be, but is not limited to, polymer materials such as amorphous fluororesin (CYTOP); the material of the waterproof layer may be, but is not limited to, polymer materials such as phenolic resin and polyimide; the sensitive electrode functionalization modification layer 231 needs to be selected according to the specific substance to be detected. For example, platinum metal nanoparticles or other metal oxides for detecting glucose, etc.; the types of field effect transistors may be, but is not limited to, commercial metal-oxide-semiconductor field effect transistors and thin film transistors. If the substance to be detected needs to adjust the potential at the interface between the sensitive electrode and the solution to a higher value, a p-type transistor is selected. If the substance to be detected needs to adjust the potential at the interface between the sensitive electrode and the solution to a lower value, an n-type transistor is selected; the reference electrode coating may be, but is not limited to, commercial standard hydrogen electrode coating, silver / silver chloride coating.

[0090] An electrochemical sensing system, comprising:

[0091] The above-mentioned electrochemical sensor based on the 1T1C structure;

[0092] A voltage driving and current reading unit; the voltage driving and current reading unit is electrically connected to the reference electrode and the source and drain of the field effect transistor through three electrical contact terminals, and is used to apply voltages to the reference electrode and the source and drain of the field effect transistor, and simultaneously read the output drain current;

[0093] A signal processing unit; the signal processing unit is used to generate a calibration curve of the concentration of the analyte and the output drain current value in the calibration step, and convert the read drain current value into the corresponding concentration information of the analyte according to the calibration curve in the test step.

[0094] A polymer cell; a polymer cell for containing calibration solution and the solution to be detected, and the polymer cell surrounds the area where the sensitive electrode and the reference electrode are located. The material of the polymer cell may be, but is not limited to, polydimethylsiloxane (PDMS), silicone rubber. Specific embodiments

[0096] Example 1

[0097] Figure 1 It is a schematic diagram of an electrochemical sensor structure that selects an organic thin-film transistor (OTFT) and a solid-state supercapacitor provided in a preferred embodiment of the present invention. As Figure 1 shown, the electrochemical sensor includes:

[0098] A bottom gate electrode 111 disposed on the surface of the substrate 0, the material of the substrate 0 is polyethylene naphthalate (PEN), and the material of the bottom gate electrode 111 is gold;

[0099] A bottom gate insulating layer 112 covering the bottom gate electrode 111, the material of the bottom gate insulating layer 112 is polyvinyl cinnamate (PVCN);

[0100] A drain electrode 113 and a source electrode 114 disposed on the surface of the bottom gate insulating layer 112 in the same layer, the materials of the drain electrode 113 and the source electrode 114 are gold;

[0101] An organic semiconductor layer 115 covering the drain electrode 113, the source electrode 114, and the area between the drain electrode 113 and the source electrode 114, the material of the organic semiconductor layer 115 is pentacene (TIPS-pentacene);

[0102] A first encapsulation layer 116 covering the semiconductor layer 115, the material of the first encapsulation layer 116 is amorphous fluororesin (CYTOP);

[0103] A waterproof layer 117 covering the first encapsulation layer 116, the material of the waterproof layer 117 is polyimide (PI);

[0104] A first electrode 121, a second electrode 123, and a third electrode 141 disposed on the surface of the waterproof layer 117 in the same layer, the materials of the first electrode 121, the second electrode 123, and the third electrode 141 are gold;

[0105] A first electrode supercapacitor electrode material layer 122 modified on the surface of the first electrode 121 and a second electrode supercapacitor electrode material layer 124 modified on one end surface of the second electrode 123, the materials of the first electrode supercapacitor electrode material layer 122 and the second electrode supercapacitor electrode material layer 124 are carbon black (CB);

[0106] A solid electrolyte layer 125 covering the first electrode supercapacitor electrode material layer 121 and the second electrode supercapacitor electrode material layer 124, and the area between the two, the material of the solid electrolyte layer 125 is poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS);

[0107] The sensitive electrode functionalized modification layer 131 disposed on the upper surface of the other end of the second electrode 123;

[0108] The silver / silver chloride layer 142 disposed on the upper surface of the third electrode 141;

[0109] The first through hole 151 connecting the source electrode 114 and the first electrode 121; a conductive medium is provided in the first through hole 151;

[0110] The second through hole 161 connecting the bottom gate electrode 111 and the second electrode 123; a conductive medium is provided in the second through hole 161; the materials of the first through hole 151 and the second through hole 161 are gold;

[0111] The second encapsulation layer 171 disposed on the waterproof layer 117 and the solid electrolyte layer 125, and two through holes exposing the sensitive electrode functionalized modification layer 131 and the silver / silver chloride layer 142 are provided in the second encapsulation layer 171, and the material of the second encapsulation layer 171 is amorphous fluororesin (CYTOP).

[0112] Figure 1 The two dashed boxes in respectively represent the organic thin film transistor 11 and the solid-state supercapacitor 12. The organic thin film transistor 11 can convert the potential response of the sensitive electrode to the substance to be detected into a current response output, and the solid-state supercapacitor 12 can adjust the potential difference at the interface between the sensitive electrode and the solution to meet the overpotential requirements for the oxidation and reduction of the substance to be detected.

[0113] The sensitive electrode functionalized modification layer 131 needs to be selected according to a specific substance to be detected. For example, platinum metal nanoparticles or other metal oxides for detecting glucose, etc.

[0114] In the actual detection process, the sensitive electrode functionalized modification layer 131 and the silver / silver chloride layer 142 are immersed in the solution to be detected together. Select a suitable capacitance value of the supercapacitor so that when adjusting the bias voltage at the reference electrode end, the potential at the interface between the sensitive electrode and the solution can meet the overpotential requirements of the substance to be detected, and at the same time the organic field effect transistor should operate in the saturation region or the subthreshold region. Due to the change in the concentration of the target substance in the solution to be detected, the potential at the interface between the sensitive electrode and the solution changes accordingly, and the change in the interface potential is converted into a change in the drain current output through the organic field effect transistor.

[0115] Embodiment 2

[0116] Figure 2 is a schematic structural diagram of an electrochemical sensing system based on a 1T1C structure provided in a preferred embodiment of the present invention. As Figure 2As shown, the electrochemical sensing system includes:

[0117] Substrate 0;

[0118] Sensing electrode 1;

[0119] Reference electrode 2;

[0120] Field effect transistor 4;

[0121] A capacitor 3 connected in parallel between the source and gate of the field effect transistor 4;

[0122] A voltage driving and current reading module 5; the voltage driving and current reading unit is electrically connected to the reference electrode and the source and drain of the field effect transistor through three electrical contact terminals, and is used to apply voltages to the reference electrode and the source and drain of the field effect transistor, and at the same time read the output drain current;

[0123] Signal processing module 6.

[0124] A polymer groove 7 disposed on the substrate 0 and surrounding the regions of the sensing electrode 1 and the reference electrode 2. The polymer groove 7 is used to place a calibration solution or a solution to be detected, and the material of the polymer groove 7 is polydimethylsiloxane (PDMS).

[0125] During the actual detection process, a solution to be detected is placed in the polymer groove, the voltage driving and current reading module applies voltages to the reference electrode and the source and drain of the field effect transistor, and at the same time reads the output drain current, and the signal processing module converts the obtained current value into the concentration information of the corresponding analyte.

[0126] Figure 3 In a preferred embodiment of the present invention, in an epitaxial gate type field effect transistor sensor (with the same structure as in Example 1) constructed by using an aluminum electrolytic capacitor for the capacitor, a p-type MOSFET for the field effect transistor, a carbon fiber electrode modified with platinum nanoparticles for the sensing electrode, and a commercial silver / silver chloride electrode for the reference electrode, when the capacitance value of the aluminum electrolytic capacitor changes, the change of the transfer characteristic curve of the p-type MOSFET. The test is carried out in 0.1 M phosphate buffer solution, and the pH value of the phosphate buffer solution is 7.4. Figure 3 It shows that the larger the capacitance value of the parallel capacitor, the smaller the slope of the obtained transfer characteristic curve in the saturation region, because a part of the bias voltage applied at the reference electrode end drops at the interface between the sensing electrode and the solution, and the voltage drop actually distributed between the gate and source of the field effect transistor is regulated by the capacitance value of the parallel capacitor. Figure 4In a preferred embodiment of the present invention, in the epitaxial gate-type field effect transistor sensor (with the same structure as in Example 1) constructed by selecting an aluminum electrolytic capacitor as the capacitor, a p-type MOSFET as the field effect transistor, a carbon fiber electrode modified with platinum nanoparticles as the sensitive electrode, and a commercial silver / silver chloride electrode as the reference electrode, when the capacitance value of the aluminum electrolytic capacitor changes, the potential difference between the sensitive electrode and the reference electrode varies with the change of the bias voltage at the reference electrode terminal. The test is carried out in a 0.1 M phosphate buffer solution with a pH value of 7.4. Since the potential difference at the interface between the reference electrode and the solution remains unchanged, the potential difference between the sensitive electrode and the reference electrode can reflect the potential difference at the interface between the sensitive electrode and the solution.

[0127] Figure 4 It shows that the potential difference at the interface between the sensitive electrode and the solution is simultaneously regulated by the capacitance value of the parallel capacitor and the bias voltage at the reference electrode terminal. As a control group, when there is no parallel capacitor, the potential difference at the interface between the sensitive electrode and the solution can hardly be regulated by the bias voltage at the reference electrode. When there is a parallel capacitor, the larger its capacitance value, the more obvious the change of the potential difference at the interface between the sensitive electrode and the solution with the change of the bias voltage at the reference electrode.

[0128] Figure 5 In a preferred embodiment of the present invention, in the epitaxial gate-type field effect transistor sensor (with the same structure as in Example 1) constructed by selecting an aluminum electrolytic capacitor as the capacitor, a p-type MOSFET as the field effect transistor, a carbon fiber electrode modified with platinum nanoparticles as the sensitive electrode, and a commercial silver / silver chloride electrode as the reference electrode, while fixing the source-drain voltage of the field effect transistor and the bias voltage at the reference electrode terminal, when the glucose concentration in the calibration solution changes, the change of the output drain current is monitored. The test is carried out in a 0.1 M phosphate buffer solution with a pH value of 7.4, and a high-concentration glucose aqueous solution is added during the test to achieve the effect of increasing the glucose concentration in the whole test solution. Attached Figure 5 It shows that when the capacitor selects an appropriate capacitance value (here it is 50 μF) and the driving voltage is set appropriately (here the bias voltage at the reference electrode terminal is set to -2.95 V and the source-drain voltage is set to 1.5 V), the output drain current has a linear relationship with the glucose concentration. This linear relationship serves as a calibration curve for detecting other samples.

[0129] Figure 6In a preferred embodiment of the present invention, in the epitaxial gate type field effect transistor sensor (with the same structure as in Embodiment 1) constructed by selecting an aluminum electrolytic capacitor for the capacitor, an n-type MOSFET for the field effect transistor, a carbon fiber electrode modified with platinum nanoparticles for the sensitive electrode, and a commercial silver / silver chloride electrode for the reference electrode, when the capacitance value of the aluminum electrolytic capacitor changes, the potential difference between the sensitive electrode and the reference electrode varies with the change of the bias voltage at the reference electrode terminal. The test is carried out in a 0.1 M phosphate buffer solution with a pH value of 7.4, and the solution is continuously purged with nitrogen until saturated. Similar to Figure 4 Similar, Figure 6 It shows that after connecting the parallel capacitor, the interfacial potential difference between the sensitive electrode and the solution is regulated by the bias voltage at the reference electrode terminal, and the larger the capacitance value of the capacitor, the more obvious the regulation effect.

[0130] Figure 7 In a preferred embodiment of the present invention, in the epitaxial gate type field effect transistor sensor (with the same structure as in Embodiment 1) constructed by selecting an aluminum electrolytic capacitor for the capacitor, an n-type MOSFET for the field effect transistor, a carbon fiber electrode modified with platinum nanoparticles for the sensitive electrode, and a commercial silver / silver chloride electrode for the reference electrode, with the source-drain voltage of the MOSFET and the bias voltage at the reference electrode terminal fixed, when the oxygen concentration in the calibration solution changes, the change of the output drain current is monitored. The test is carried out in a 0.1 M phosphate buffer solution with a pH value of 7.4, and the change of the oxygen concentration in the solution is achieved by adjusting the oxygen partial pressure in the purged gas during the test. Figure 7 It shows that when the capacitor selects a suitable capacitance value (here it is 100 μF) and the driving voltage is set appropriately (here the bias voltage at the reference electrode terminal is set to 2.1 V and the source-drain voltage is set to -1.5 V), the output drain current has a linear relationship with the oxygen concentration. This linear relationship serves as the calibration curve for detecting other samples.

[0131] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning, or limited experiments based on the concept of the present invention on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. An electrochemical sensor based on a 1T1C structure, characterized in that Comprising: A substrate; A bottom gate electrode disposed on the upper surface of the substrate; A bottom gate insulating layer covering the bottom gate electrode; A drain electrode and a source electrode disposed on the surface of the bottom gate insulating layer in the same layer; An organic semiconductor layer covering the drain electrode, the source electrode, and the region between the drain electrode and the source electrode of the bottom gate insulating layer; A first encapsulation layer covering the semiconductor layer; A waterproof layer covering the first encapsulation layer; A first electrode, a second electrode, and a third electrode disposed on the surface of the waterproof layer in the same layer; A first electrode supercapacitor electrode material layer modified on the surface of the first electrode and a second electrode supercapacitor electrode material layer modified on the upper surface of one end of the second electrode; A solid electrolyte layer covering the first electrode supercapacitor electrode material layer, the second electrode supercapacitor electrode material layer, and the region between the two of the waterproof layer; A sensitive electrode functionalized modification layer disposed on the upper surface of the other end of the second electrode; A reference electrode coating disposed on the upper surface of the third electrode; A first through hole connecting the source electrode and the first electrode and having a conductive medium therein; A second through hole connecting the bottom gate electrode and the second electrode and having a conductive medium therein; A second encapsulation layer disposed above the waterproof layer and the solid electrolyte layer, and two through holes exposing the sensitive electrode functionalized modification layer and the reference electrode coating are provided in the second encapsulation layer.

2. The electrochemical sensor based on the 1T1C structure according to claim 1, wherein: The material of the substrate is selected from a PCB board, a silicon wafer, polyimide, polyethylene naphthalate, and polyethylene terephthalate.

3. The electrochemical sensor based on the 1T1C structure according to claim 1, characterized in that: The materials of the bottom gate electrode, the drain electrode, the source electrode, the first electrode, the second electrode, the third electrode, and the conductive medium in the first through hole / second through hole are all inert electrode materials with low chemical reactivity.

4. The electrochemical sensor based on the 1T1C structure according to claim 1, characterized in that: The material of the bottom gate insulating layer is selected from polyvinyl cinnamate or polyvinylidene fluoride.

5. The electrochemical sensor based on the 1T1C structure according to claim 1, characterized in that: The material of the organic semiconductor layer is an organic conductive small molecule material.

6. The electrochemical sensor based on the 1T1C structure according to claim 1, characterized in that: The materials of the first encapsulation layer and the second encapsulation layer are amorphous fluororesins.

7. The electrochemical sensor based on the 1T1C structure according to claim 1, characterized in that: The material of the waterproof layer is selected from phenolic resin and polyimide.

8. The electrochemical sensor based on the 1T1C structure according to claim 1, characterized in that: The reference electrode coating is selected from a standard hydrogen electrode coating and a silver / silver chloride coating.

9. An electrochemical sensing system, characterized in that Comprising: The electrochemical sensor based on the 1T1C structure according to any one of claims 1-8; A voltage driving and current reading unit; the voltage driving and current reading unit is electrically connected to the reference electrode and the source electrode and the drain electrode of the field effect transistor through three electrical contact terminals, and is used to apply voltages to the reference electrode and the source electrode and the drain electrode of the field effect transistor, and simultaneously read the output drain current; A signal processing unit; The signal processing unit is used to generate a calibration curve of the concentration of the analyte and the output drain current value in the calibration step, and convert the read drain current value into the corresponding concentration information of the analyte according to the calibration curve in the test step.

10. The electrochemical sensing system according to claim 9, wherein: It further includes a polymer tank for containing a calibration solution and a solution to be detected; the polymer tank surrounds the region where the sensitive electrode and the reference electrode are located.

11. The electrochemical sensing system according to claim 10, wherein: The material of the polymer tank is selected from polydimethylsiloxane and silicone rubber.

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