Alkali-doped organic electrochemical transistor, dissolved oxygen sensing patch and applications thereof

Abstract

The application relates to the field of sensing devices, and discloses a base-doped organic electrochemical transistor, a dissolved oxygen sensing patch and application thereof. The base-doped organic electrochemical transistor comprises a substrate, a dissolved oxygen sensitive gate, a source electrode, a drain electrode and a base-doped semiconductor layer between the source electrode and the drain electrode. The dissolved oxygen sensing patch comprises the base-doped organic electrochemical transistor and a flexible water-absorbing substrate. The PSS:PEDOT semiconductor layer in the organic electrochemical transistor is subjected to base-doping modification treatment, so that the sub-threshold region just coincides with the oxygen reduction potential, the advantages of the transconductance effect of the organic electrochemical transistor can be fully exerted, and the sensitivity of the sensor is greatly improved. The dissolved oxygen sensitive gate in the base-doped organic electrochemical transistor has the advantages of high selectivity and high sensitivity to oxygen, good robustness and low cost and can be mass-produced.

Description

Technical Field

[0001] This invention relates to the field of sensor devices, and more particularly to an alkaline-doped organic electrochemical transistor, a dissolved oxygen sensing patch, and their applications. Background Technology

[0002] In the human body, due to the low solubility of oxygen, 98%-99% of oxygen binds to hemoglobin, with the remaining small portion existing as dissolved oxygen. Medical oxygen monitoring primarily focuses on two indicators: blood oxygen saturation and dissolved oxygen concentration. The former refers to the percentage of oxygen bound to hemoglobin (Hb), reflecting the body's utilization and binding of oxygen, and can indirectly reflect the degree of tissue hypoxia, but it may mask the potential danger of hypoxia. In contrast, dissolved oxygen can more accurately reflect the degree of localized hypoxia in organs or tissues. Wound healing requires oxygen; enzymes involved in bacterial killing, collagen synthesis, angiogenesis, and epithelial formation require a pO2 level of 25 to 100 mmHg in wound tissue. In patients with traumatic brain injury, brain hypoxia can cause secondary irreversible brain damage, and the partial pressure of oxygen in brain tissue can accurately reflect the degree of brain hypoxia; a brain oxygen partial pressure of less than 10 mmHg is considered a dangerous state of hypoxia. Diabetes mellitus, embolism, and vascular diseases such as atherosclerosis or vasculitis can cause microcirculatory disturbances, leading to local capillary and tissue ischemia and hypoxia. Transcutaneous oxygen partial pressure monitoring not only reflects the actual oxygen supply to skin tissue cells and the state of macrocirculation, but also directly reflects the functional status of microvessels, effectively assessing ischemia and hypoxia caused by lower extremity arterial and capillary diseases. It can be used to diagnose lower extremity arteriosclerosis obliterans, detect the early risk of diabetic foot ulcers, assess the prognosis of foot ulcer healing, determine the amputation level, and monitor changes in the condition.

[0003] Currently, commonly used oxygen sensor detection methods include optical and electrochemical methods. These methods rely on bulky detection equipment and cannot achieve rapid and convenient real-time detection. Electrochemical sensors, on the other hand, have excellent research prospects due to their high detection sensitivity and ease of integration.

[0004] Currently, miniaturized electrochemical sensors are mostly based on three-electrode systems. However, the small size of the sensitive electrode leads to weak changes in the response electrical signal, which undoubtedly poses a challenge to signal readout and amplification in backend devices. In response, organic electrochemical transistors (OECTs) have attracted widespread attention in the fields of flexible electronics and biochemical sensing due to their simple structure, low manufacturing cost, and good biocompatibility. Researching novel organic electrochemical transistor-based sensors to achieve highly sensitive portable detection of dissolved oxygen is a valuable technical challenge. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an alkali-doped organic electrochemical transistor, a dissolved oxygen sensing patch, and their applications. In this invention, the PSS:PEDOT semiconductor layer of the organic electrochemical transistor undergoes alkali doping modification, causing the subthreshold region to coincide with the oxygen reduction potential. This fully leverages the transconductance effect of the organic electrochemical transistor, significantly improving the sensor's sensitivity and providing a new approach for measuring dissolved oxygen and transdermal oxygen partial pressure. The dissolved oxygen sensing gate of this invention exhibits high sensitivity to dissolved oxygen, good robustness, and low-cost, large-scale fabrication advantages.

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

[0007] In a first aspect, the present invention provides a base-doped organic electrochemical transistor, comprising:

[0008] Substrate;

[0009] Dissolved oxygen sensitive gate disposed on the substrate;

[0010] The source electrode is disposed on the substrate;

[0011] Drain electrode disposed on the substrate;

[0012] An alkali-doped semiconductor layer is disposed on the substrate, located between the source and the drain, and connected to the source and the drain; the material of the alkali-doped semiconductor layer is PEDOT:PSS semiconductor modified by organic alkali doping.

[0013] The working principle of the alkali-doped organic electrochemical transistor of the present invention is as follows: During detection, the dissolved oxygen sensitive gate is in full contact with the system to be detected. The oxygen to be detected diffuses to the surface of the dissolved oxygen sensitive gate near the electrode. Under the catalysis of the negative gate voltage and the oxygen reduction catalyst in the dissolved oxygen sensitive gate, a redox reaction occurs, thereby increasing the voltage distribution between the dissolved oxygen sensitive gate and the solution, while the voltage distribution at the channel (i.e., the alkali-doped semiconductor layer between the source and drain) decreases, resulting in a reduction in positive ion insertion. Therefore, the source and drain currents will increase with the increase of oxygen concentration. Thus, the concentration of target molecules in the solution can be determined based on the magnitude of the drain current.

[0014] To improve device sensitivity, the operating region of an organic electrochemical transistor (OLED) is preferably the subthreshold region. For commonly used p-type depletion-mode PEDOT:PSS semiconductors, the subthreshold region is located in the positive potential region. However, the overlap of negative potentials with oxygen reduction reactions is low, and the current change in the transfer characteristic curve is not significant, failing to fully utilize the transconductance gain of the OLED to improve device sensitivity. Therefore, this invention dops a conventional PEDOT:PSS semiconductor solution with an organic base. The positively charged amine groups compensate for the charge difference with the negatively charged sulfonic acid groups in PSS, thereby reducing the amount of positive charge in PEDOT. This pre-embedding mechanism allows the OLED to be transformed into an enhancement-mode device, placing the subthreshold region in the negative potential region. Preferably, the method for preparing the organic base-doped PEDOT:PSS semiconductor is as follows: an organic base is added to the PEDOT:PSS semiconductor solution to modify it into a p-type enhancement-mode semiconductor, i.e., an organic base-doped PEDOT:PSS semiconductor; the volume fraction of the organic base is 5-40% of the PEDOT:PSS semiconductor solution.

[0015] The invention team discovered that the amount of organic base used has a significant impact on the final result. If the amount of organic base is too small, the doping effect will be poor; if the amount of organic base is too large, the excess oil-phase organic amines are prone to separation with the aqueous semiconductor solution, making it difficult to form a homogeneous phase and resulting in discontinuous film formation. On the other hand, it will also increase the overall viscosity of the system, which is not conducive to device fabrication.

[0016] Preferably, the organic base is selected from ethylenediamine (EDA), diethylenetriamine (DETA), N-methyl-2,2′-diaminodiethylamine (DEMTA), and tri(aminoethyl)amine (TAEA).

[0017] Preferably, the substrate is selected from flexible substrates such as fiber substrates, silicon substrates, sodium calcium glass substrates, and polyethylene naphthalate (PEN) substrates, among others.

[0018] Preferably, the source and drain electrodes are fibrous electrodes or planar electrodes; wherein, the fibrous electrodes are selected from, but are not limited to, carbon fibers, carbon nanotube fibers, etc.; the planar electrodes are selected from, but are not limited to, planar gold electrodes, planar silver electrodes, planar indium tin oxide electrodes, etc.

[0019] Preferably, the dissolved oxygen sensitive gate includes:

[0020] Conductive substrate;

[0021] Oxygen reduction catalyst attached to the surface of the conductive substrate;

[0022] An inner encapsulation layer covering the surface of the catalyst;

[0023] An outer encapsulation layer that covers the surface of the inner encapsulation layer.

[0024] The dissolved oxygen sensitive gate of the present invention has the advantages of high selectivity and high sensitivity to oxygen, good robustness, and low cost and large-scale fabrication.

[0025] Furthermore, the dissolved oxygen sensitive gate of the present invention is designed with inner and outer dual encapsulation layers. The advantage of this design is that the inner encapsulation layer is conducive to oxygen reaction, repels negatively charged substances, reduces interference, and provides hydrogen ions in the ORR reaction (e.g., Nafion is selected as the inner encapsulation layer). The outer encapsulation layer can improve mechanical properties while protecting the inner encapsulation layer (e.g., PDMS is selected as the outer encapsulation layer).

[0026] Preferably, the conductive substrate is a carbon fiber electrode or a planar gold electrode.

[0027] Preferably, the oxygen reduction catalyst is platinum metal nanoparticles with a particle size of less than or equal to 10 nm.

[0028] When loading catalysts, platinum metal nanoparticles can be obtained by chemical reduction. For fibrous electrodes, the fibrous electrodes can be directly immersed in the solution and loaded by chemical reduction. For planar electrodes, the catalyst can be directly drop-coated onto the planar electrode.

[0029] Preferably, the inner encapsulation layer is a Nafion encapsulation layer; and the outer encapsulation layer is a PDMS encapsulation layer.

[0030] In preparing the coating, Nafion was first used to coat and dry the electrode on which the oxygen reduction catalyst was deposited, and then the electrode was further encapsulated using PDMS solution.

[0031] In a second aspect, the present invention provides a dissolved oxygen sensing patch, comprising:

[0032] Alkali-doped organic electrochemical transistors; and

[0033] A flexible water-absorbing substrate is disposed on the substrate surface of the alkali-doped organic electrochemical transistor and covers part of the dissolved oxygen sensitive gate, part of the source, part of the drain and all of the alkali-doped semiconductor layer.

[0034] Preferably, the flexible absorbent substrate is a flexible cotton substrate.

[0035] Thirdly, the present invention provides a method for detecting dissolved oxygen using the above-mentioned dissolved oxygen sensing patch: during detection, the entire dissolved oxygen sensing patch is immersed in the solution to be detected, and the source-drain current is read by fixing the gate-source voltage and source-drain voltage of the electrochemical transistor to perform real-time oxygen detection.

[0036] Fourthly, the present invention provides a method for detecting transdermal oxygen partial pressure: before testing, the area to be tested is cleaned with alcohol, then an oxygen-free electrolyte solution is dropped onto the flexible absorbent substrate of the dissolved oxygen sensing patch to wet the alkali-doped semiconductor layer and the dissolved oxygen sensitive gate to form a circuit, then the dissolved oxygen sensing patch is attached to the area to be tested, a bias voltage is applied to the source and drain terminals of the organic electrochemical transistor and the dissolved oxygen sensitive gate terminal using a matching voltage bias unit, the area to be tested is heated to 40-45 degrees Celsius, the stable value of the leakage current is read using a matching current reading unit, and converted into oxygen concentration according to the calibration curve.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] (1) The PSS:PEDOT semiconductor layer in the organic electrochemical transistor of the present invention is modified by alkaline doping so that the subthreshold region coincides with the oxygen reduction potential. This can give full play to the transconductance effect of the organic electrochemical transistor, greatly improve the sensitivity of the sensor, and provide a new approach for the testing of dissolved oxygen and transdermal oxygen partial pressure.

[0039] (2) The present invention provides a dissolved oxygen sensitive gate that is highly selective for oxygen, and the dissolved oxygen sensitive gate has the advantages of high sensitivity, good robustness and low cost and large-scale fabrication. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a method for preparing a carbon fiber-based dissolved oxygen sensitive electrode according to Embodiment 1 of the present invention;

[0041] Figure 2 This is a scanning electron microscope image of the dissolved oxygen sensitive electrode based on carbon fiber in specific embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the organic electrochemical transistor and dissolved oxygen sensitive electrode in specific embodiment 3 of the present invention;

[0043] Figure 4 This is the gradient curve of the real-time response of dissolved oxygen detection in a specific embodiment of the present invention;

[0044] Figure 5 This is a calibration curve of output current and dissolved oxygen content in a specific embodiment of the present invention.

[0045] The attached figures are labeled as follows: outer skin 300, flexible substrate 301, flexible cotton substrate 302, carbon fiber 311, platinum nanoparticles 312, Nafion encapsulation layer 313, PDMS encapsulation layer 314, source electrode 321, drain electrode 322, and alkali-doped semiconductor layer 323. Detailed Implementation

[0046] General Implementation Examples

[0047] A base-doped organic electrochemical transistor, comprising:

[0048] Substrate;

[0049] Dissolved oxygen sensitive gate disposed on the substrate;

[0050] The source electrode is disposed on the substrate;

[0051] Drain electrode disposed on the substrate;

[0052] An alkali-doped semiconductor layer is disposed on the substrate, located between the source and the drain, and connected to the source and the drain; the material of the alkali-doped semiconductor layer is PEDOT:PSS semiconductor modified by organic alkali doping.

[0053] Preferably, the method for preparing the organic base-doped modified PEDOT:PSS semiconductor is as follows: an organic base is added to the PEDOT:PSS semiconductor solution to modify the PEDOT:PSS semiconductor into a p-type enhancement-mode semiconductor, which is the organic base-doped modified PEDOT:PSS semiconductor; the volume fraction of the organic base is 5-40% of the PEDOT:PSS semiconductor solution. The organic base is selected from ethylenediamine (EDA), diethylenetriamine (DETA), N-methyl-2,2′-diaminodiethylamine (DEMTA), and tri(aminoethyl)amine (TAEA).

[0054] Preferably, the substrate is selected from, but is not limited to, flexible substrates such as fiber substrates, silicon substrates, sodium calcium carbonate glass substrates, and polyethylene naphthalate (PEN) substrates. The source and drain electrodes are either fibrous electrodes or planar electrodes; wherein, the fibrous electrodes are selected from, but are not limited to, carbon fibers and carbon nanotube fibers; and the planar electrodes are selected from, but are not limited to, planar gold electrodes, planar silver electrodes, and planar indium tin oxide electrodes.

[0055] Preferably, the dissolved oxygen sensitive gate includes:

[0056] Conductive substrate;

[0057] Oxygen reduction catalyst attached to the surface of the conductive substrate;

[0058] An inner encapsulation layer covering the surface of the catalyst;

[0059] An outer encapsulation layer covering the surface of the Nafion encapsulation layer.

[0060] Preferably, the conductive substrate is a carbon fiber electrode or a planar gold electrode. The oxygen reduction catalyst is platinum metal nanoparticles with a particle size of 10 nm or less. The inner encapsulation layer is a Nafion encapsulation layer; the outer encapsulation layer is a PDMS encapsulation layer.

[0061] A dissolved oxygen sensing patch, comprising:

[0062] Alkali-doped organic electrochemical transistors; and

[0063] A flexible absorbent substrate is disposed on the substrate surface of the alkali-doped organic electrochemical transistor and covers part of the dissolved oxygen-sensitive gate, part of the source, part of the drain, and the entire alkali-doped semiconductor layer. Preferably, the flexible absorbent substrate is a flexible cotton substrate.

[0064] A method for detecting dissolved oxygen using the above-mentioned dissolved oxygen sensing patch: During detection, the entire dissolved oxygen sensing patch is immersed in the solution to be detected, and the source-drain current is read by fixing the gate-source voltage and source-drain voltage of the electrochemical transistor to detect oxygen in real time.

[0065] A method for detecting transdermal oxygen partial pressure: Before testing, the area to be tested is cleaned with alcohol. Then, an oxygen-free electrolyte solution is dropped onto the flexible absorbent substrate of the dissolved oxygen sensing patch to wet the alkali-doped semiconductor layer and the dissolved oxygen sensitive gate to form a circuit. The dissolved oxygen sensing patch is then attached to the area to be tested. A bias voltage is applied to the source / drain terminals of the organic electrochemical transistor and the dissolved oxygen sensitive gate terminal using a matching voltage bias unit. The area to be tested is heated to 40-45 degrees Celsius. The stable value of the leakage current is read using a matching current reading unit and converted into oxygen concentration according to the calibration curve. Specific Implementation

[0067] The technical solution provided by the present invention will be further described in detail below with reference to the accompanying drawings.

[0068] Example 1

[0069] A method for fabricating a carbon fiber-based dissolved oxygen sensitive electrode involves using carbon fiber as a substrate, modifying the carbon fiber surface with platinum metal nanoparticles through chemical reduction and physical adsorption, and then coating it with a Nafion encapsulation layer and a PDMS encapsulation layer to improve its anti-interference properties and provide protection. Figure 1 As shown, the specific steps include:

[0070] Step 1: Separate the carbon fiber from the carbon cloth and cut it into 3 cm pieces. Then, ultrasonically clean and dry the fibers with ethanol and deionized water for 10 minutes in sequence to remove grease and dust from the fiber surface.

[0071] Step 2: Prepare 10 ml of 2.5 mM chloroplatinic acid aqueous solution and 10 ml of 25 mM sodium borohydride aqueous solution. Soak the carbon fiber in 10 mL of chloroplatinic acid aqueous solution (1 mM) for about 30 minutes. Add 1 mL of sodium borohydride solution to the chloroplatinic acid solution and stir vigorously for 60 minutes. Then refrigerate at 5°C for 12 hours.

[0072] Step 3: Remove the carbon fibers, wash and dry them with deionized water to obtain CFs / Pt. Finally, prepare a 0.5 wt% Nafion ethanol solution and a 20 wt% p-xylene PDMS solution. First, coat the CFs / Pt with Nafion and dry at 60°C for 60 minutes, then coat the CFs / Pt with PDMS and dry at 60°C for 60 minutes.

[0073] In other embodiments, the conductive substrate can be fibrous or planar depending on the form of the electrode. The fibrous electrode can be, but is not limited to, carbon fiber, carbon nanotube fiber, etc., and the planar electrode can be, but is not limited to, gold electrode, silver electrode, indium tin oxide electrode, etc.

[0074] Figure 2 A transmission electron microscope (TEM) image of a carbon fiber dissolved oxygen sensitive electrode prepared according to the above method is shown, illustrating the changes in surface morphology during electrode preparation.

[0075] When the dissolved oxygen sensitive electrode is in operation, under negative potential, oxygen in the solution diffuses to the vicinity of the dissolved oxygen sensitive electrode. Under the catalysis of platinum nanoparticles, oxygen undergoes a reduction reaction on the electrode surface. The oxygen reduction reaction rate is much smaller than the diffusion rate of oxygen from the solution to the vicinity of the electrode surface. The entire process is diffusion-controlled, so the magnitude of the reduction current is linearly related to the oxygen concentration in the solution. Detection is performed based on this correlation.

[0076] Example 2

[0077] A dissolved oxygen sensing patch, with the structure as follows Figure 3 As shown, it includes:

[0078] Alkali-doped organic electrochemical transistors; including:

[0079] Flexible substrate 301 (material for medical gas barrier tape);

[0080] A dissolved oxygen-sensitive gate disposed on the flexible substrate 301;

[0081] Source 321 (made of carbon fiber) is disposed on the flexible substrate 301.

[0082] Drain 322 (made of carbon fiber) is disposed on the flexible substrate 301.

[0083] An alkali-doped semiconductor layer 323 is disposed on the flexible substrate 301, located between the source electrode 321 and the drain electrode 322, and connected to the source electrode 321 and the drain electrode 322. The material of the alkali-doped semiconductor layer 323 is a PEDOT:PSS semiconductor modified by organic alkali doping. The preparation method is as follows: an organic alkali (N-methyl-2,2′-diaminodiethylamine (DEMTA)) is added to the PEDOT:PSS semiconductor solution (PH1000, Sigma-Aldrich) to modify the PEDOT:PSS semiconductor into a p-type enhancement semiconductor, that is, an organic alkali-doped PEDOT:PSS semiconductor. The volume fraction of the organic alkali is 30% of the PEDOT:PSS semiconductor solution.

[0084] A flexible cotton substrate 302 (located at the bottom layer and in direct contact with the outer skin 300) is disposed on the surface of the flexible substrate 301 and covers part of the dissolved oxygen sensitive gate, part of the source 321, part of the drain 322 and all of the alkali-doped semiconductor layer 323.

[0085] The dissolved oxygen sensitive gate is prepared according to the method of Example 1, and its structure is as follows: Figure 3 As shown in the dashed box, it includes:

[0086] Carbon fiber 311;

[0087] Platinum nanoparticles 312 are attached to the surface of the carbon fiber 311;

[0088] Nafion encapsulation layer 313 covering the surface of the platinum nanoparticles 312;

[0089] A PDMS encapsulation layer 314 covering the surface of the Nafion encapsulation layer 313.

[0090] During fabrication, the source and drain electrodes are first fixed on a flexible substrate used for packaging. Then, an alkali-doped semiconductor layer is fabricated. After placing the dissolved oxygen-sensitive gate in a suitable position, the three electrodes and the alkali-doped semiconductor layer are covered with a flexible cotton substrate that has water absorption function, and leads are then laid out.

[0091] Example 3

[0092] In the actual dissolved oxygen test, the entire dissolved oxygen sensing patch is immersed in the test system. The channel between the source and drain electrodes and the fiber oxygen-sensitive gate form a circuit through the test solution. The three electrodes (dissolved oxygen-sensitive gate, source, and drain) are connected to a portable power supply device. After fixing the gate-source voltage and the source and drain voltages, the oxygen content of the system can be directly read by reading the source and drain current.

[0093] During the transdermal oxygen partial pressure test, the dissolved oxygen sensing patch electrode was first calibrated by performing gradient testing in vitro. Then, an oxygen-free solution was dropped onto the flexible cotton substrate of the dissolved oxygen sensing patch and it was attached to the area to be tested. The three electrodes were connected to a portable power supply device, and a heating pad was used to apply heat to the area to be tested in real time. The temperature was controlled at 42 degrees Celsius, and the transdermal oxygen partial pressure was tested. Data was transmitted and read in real time via Bluetooth.

[0094] The above testing process includes calibration and testing steps, specifically:

[0095] The calibration steps include:

[0096] Step 1: Immerse the entire dissolved oxygen sensing patch in a solution with a known oxygen content, ensuring that the solution completely covers the dissolved oxygen sensitive gate and the alkali-doped semiconductor layer;

[0097] Step 2: Apply bias voltage to the source / drain terminals and dissolved oxygen sensitive gate terminal of the organic electrochemical transistor using the voltage bias unit, and read the stable value of the leakage current using the current reading unit.

[0098] Step 3: Dissolved oxygen solutions of different gradients are obtained by blowing mixed gas with different ratios of nitrogen and oxygen into the system to be tested. The solutions after blowing are calibrated by a dissolved oxygen meter. The current response value and the value of the dissolved oxygen meter are recorded after each blowing.

[0099] Step 4: Fit the linear relationship between "leakage current and concentration of analyte" based on the obtained data, and use it as a calibration curve.

[0100] The testing steps include:

[0101] Step 1: Immerse the entire dissolved oxygen sensing patch in a solution with a known oxygen content, ensuring that the solution completely covers the dissolved oxygen sensitive gate and the alkali-doped semiconductor layer;

[0102] Step 2: The voltage biasing unit applies a bias voltage to the source and drain terminals and the dissolved oxygen sensitive gate terminal of the organic electrochemical transistor, and the current reading unit reads the stable value of the leakage current.

[0103] Step 3: Based on the calibration curve obtained from the calibration steps, convert the leakage current value obtained from the above tests into oxygen concentration.

[0104] It is worth noting that a calibration step is required before the first measurement to obtain a calibration curve, and then the actual sample is tested. Alternatively, calibration can be performed beforehand after device fabrication, and the calibration curve can be stored in the signal analysis unit. Then, the sample solution to be tested can be obtained and the test can be performed directly. This method requires periodic updates to the calibration curve to reduce signal drift of the electrodes over time.

[0105] Figure 4The calibration curve for dissolved oxygen detection is shown in a specific embodiment of the present invention.

[0106] Figure 5 The linear fitting curves of the current response value of the present invention with the logarithms of high and low concentrations of dissolved oxygen are shown.

[0107] The above embodiments are specific preferred implementations of the present invention, and the specific features, structures, and materials described therein can be combined in any suitable manner in any embodiment. Therefore, without departing from the essence and principle of the present invention, those skilled in the art can make appropriate modifications, substitutions, simplifications, and combinations to the embodiments described in this specification, and all such modifications and substitutions should be included within the protection scope of the present invention.

Claims

1. A base-doped organic electrochemical transistor, characterized in that... include: Substrate; Dissolved oxygen sensitive gate disposed on the substrate; The source electrode is disposed on the substrate; Drain electrode disposed on the substrate; An alkali-doped semiconductor layer is disposed on the substrate, located between the source and the drain, and connected to the source and the drain; the material of the alkali-doped semiconductor layer is PEDOT:PSS semiconductor modified by organic alkali doping; The dissolved oxygen sensitive gate includes: Conductive substrate; The oxygen reduction catalyst attached to the surface of the conductive substrate is platinum metal nanoparticles with a particle size of less than or equal to 10 nm. An inner encapsulation layer covering the surface of the catalyst; An outer encapsulation layer that covers the surface of the inner encapsulation layer.

2. The base-doped organic electrochemical transistor as described in claim 1, characterized in that: The method for preparing the organic base-doped modified PEDOT:PSS semiconductor is as follows: an organic base is added to the PEDOT:PSS semiconductor solution to modify the PEDOT:PSS semiconductor into a p-type enhanced semiconductor, which is the organic base-doped modified PEDOT:PSS semiconductor; the volume fraction of the organic base is 5-40% of the PEDOT:PSS semiconductor solution.

3. The base-doped organic electrochemical transistor as described in claim 1 or 2, characterized in that: The organic base is selected from ethylenediamine, diethylenetriamine, N-methyl-2,2′-diaminodiethylamine and tri(aminoethyl)amine.

4. The base-doped organic electrochemical transistor as described in claim 1, 2, or 3, characterized in that: The substrate is selected from fiber substrate, silicon substrate, calcium sodium glass substrate, and polyethylene naphthalate substrate.

5. The base-doped organic electrochemical transistor as described in claim 1, 2, or 3, characterized in that: The source and drain electrodes are either fibrous electrodes or planar electrodes; wherein the fibrous electrodes are selected from carbon fibers and carbon nanotube fibers; and the planar electrodes are selected from planar gold electrodes, planar silver electrodes, and planar indium tin oxide electrodes.

6. The base-doped organic electrochemical transistor as described in claim 1, characterized in that: The conductive substrate is a carbon fiber electrode or a planar gold electrode; the inner encapsulation layer is a Nafion encapsulation layer. The outer encapsulation layer is a PDMS encapsulation layer.

7. A dissolved oxygen sensing patch, characterized in that... include: The base-doped organic electrochemical transistor as described in any one of claims 1-6; as well as A flexible water-absorbing substrate is disposed on the substrate surface of the alkali-doped organic electrochemical transistor and covers part of the dissolved oxygen sensitive gate, part of the source, part of the drain and all of the alkali-doped semiconductor layer.

8. The dissolved oxygen sensing patch as described in claim 7, characterized in that: The flexible absorbent substrate is a flexible cotton substrate.

9. A method for detecting dissolved oxygen using the dissolved oxygen sensing patch as described in claim 7 or 8, characterized in that: During testing, the entire dissolved oxygen sensing patch is immersed in the solution to be tested, and the source-drain current is read by fixing the gate-source voltage and source-drain voltage of the electrochemical transistor to detect oxygen in real time.

10. A method for detecting transdermal oxygen partial pressure, characterized in that: Before testing, the area to be tested is cleaned with alcohol. Then, an oxygen-free electrolyte solution is dropped onto the flexible absorbent substrate of the dissolved oxygen sensing patch as described in claim 7 or 8 to wet the alkali-doped semiconductor layer and the dissolved oxygen sensitive gate to form a circuit. The dissolved oxygen sensing patch is then attached to the area to be tested. A bias voltage is applied to the source and drain terminals of the organic electrochemical transistor and the dissolved oxygen sensitive gate terminal using a matching voltage bias unit. The area to be tested is heated to 40-45 degrees Celsius. The stable value of the leakage current is read using a matching current reading unit and converted into the oxygen concentration according to the calibration curve.

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