Flexible pressure sensor based on metal oxide thin film transistor and preparation method and application thereof

Abstract

The invention discloses a flexible pressure sensor based on a metal oxide thin film transistor and a preparation method and application thereof. The flexible pressure sensor based on the metal oxide thin film transistor comprises a flexible substrate, a gate electrode layer, a gate dielectric layer, a metal oxide channel layer, a source electrode, a drain electrode and a piezoelectric layer, the piezoelectric layer comprises a piezoelectric polymer, ZnO nanoparticles and MXene nanosheets, and the surface of the piezoelectric layer is provided with a convex micro-nano structure. The flexible pressure sensor based on the metal oxide thin film transistor has the advantages of excellent electrical properties, good flexibility, high sensitivity, easy integration, simple preparation process and low cost, is suitable for the production of large-scale sensor arrays, and has very wide application prospects in the fields of flexible touch screens, human-computer interaction, electronic skin and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensing, and particularly relates to a flexible pressure sensor based on a metal oxide thin film transistor, a preparation method thereof, and an application thereof. Background Art

[0002] A pressure sensor is a device that can sense a pressure signal and convert the pressure signal into an output electrical signal according to a certain mechanism, and it has very broad application prospects in many fields such as the automotive industry, aerospace, robot tactile recognition, object detection, medical health monitoring, etc. The piezoelectric pressure sensor can generate an electrical signal without an external power supply and is an ideal choice for detecting subtle pressure changes. However, the existing piezoelectric pressure sensors generally have problems such as poor flexibility, low sensitivity, limited pressure detection range, and cannot meet the development requirements of miniaturization, integration, modularization, and intelligence, and their applications are greatly restricted.

[0003] Therefore, it is of great significance to develop a piezoelectric pressure sensor with good flexibility, high integration, and high sensitivity. Summary of the Invention

[0004] The purpose of the present invention is to provide a flexible pressure sensor based on a metal oxide thin film transistor, a preparation method thereof, and an application thereof.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A flexible pressure sensor based on a metal oxide thin film transistor, which comprises a flexible substrate, a gate electrode layer, a gate dielectric layer, and a metal oxide channel layer stacked in sequence, and further comprises a source electrode, a drain electrode, and a piezoelectric layer disposed on the side of the metal oxide channel layer away from the gate dielectric layer; the piezoelectric layer is composed of a piezoelectric polymer, ZnO nanoparticles, and MXene nanosheets; the surface of the piezoelectric layer has a convex micro-nano structure.

[0007] Preferably, the flexible substrate is one of a flexible polycarbonate substrate, a flexible polydimethylsiloxane substrate, a flexible polymethyl methacrylate substrate, a flexible polyethylene terephthalate substrate, and a flexible polyimide substrate.

[0008] Preferably, the thickness of the flexible substrate is 15 μm to 25 μm.

[0009] Preferably, the gate electrode layer is one of an Al layer, an Al-Nd layer, and an ITO layer.

[0010] Preferably, the thickness of the gate electrode layer is 100 nm to 200 nm.

[0011] Preferably, the gate dielectric layer is one of a silicon dioxide layer, an aluminum oxide layer, and a neodymium aluminum oxide layer.

[0012] Preferably, the thickness of the gate dielectric layer is 180 nm to 280 nm.

[0013] Preferably, the metal oxide channel layer is one of an indium zinc oxide layer, a tin zinc oxide layer, an indium tin zinc oxide layer, an indium gallium zinc oxide layer, and a zirconium indium tin zinc oxide layer.

[0014] Preferably, the thickness of the metal oxide channel layer is 50 nm to 100 nm, the channel length is 200 μm to 500 μm, and the channel width is 200 μm to 500 μm.

[0015] Preferably, the source electrode is one of an ITO electrode, an Al electrode, a Cu electrode, and an Au electrode.

[0016] Preferably, the thickness of the source electrode is 80 nm to 180 nm.

[0017] Preferably, the drain electrode is one of an ITO electrode, an Al electrode, a Cu electrode, and an Au electrode.

[0018] Preferably, the thickness of the drain electrode is 80 nm to 180 nm.

[0019] Preferably, the total mass percentage of ZnO nanoparticles and MXene nanosheets in the piezoelectric layer is 25% to 35%.

[0020] Preferably, the mass ratio of ZnO nanoparticles to MXene nanosheets in the piezoelectric layer is 5 to 20:1.

[0021] Preferably, the piezoelectric polymer is at least one of polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), and poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)).

[0022] Preferably, the shape of the ZnO nanoparticles is at least one of spherical, prismatic, and flower-like, and the particle size is 320 nm to 520 nm.

[0023] Preferably, the ZnO nanoparticles are prepared by a preparation method including the following steps: adding a zinc salt, hexamethylenetetramine, and water into a hydrothermal reaction kettle, reacting at 95°C to 115°C for 2 h to 10 h, and then taking the solid product for cleaning and drying.

[0024] Preferably, the MXene nanosheet is Ti 2 CT x -MXene nanosheet, Ta 4 C3 T x - MXene nanosheets, Nb 2 CT x - MXene nanosheets, V 2 CT x - MXene nanosheets, Nb 4 C 3 T x - MXene nanosheets, Mo 2 CT x At least one of the - MXene nanosheets.

[0025] Preferably, the diameter of the MXene nanosheets is 0.2 μm to 1 μm.

[0026] Preferably, the MXene nanosheets are made by a preparation method including the following steps: adding water to disperse MXene to form a MXene dispersion, and then performing freeze-drying.

[0027] Preferably, the thickness of the piezoelectric layer is 5 μm to 20 μm.

[0028] A preparation method of a flexible pressure sensor based on a metal oxide thin film transistor as described above includes the following steps:

[0029] 1) Sequentially deposit a gate electrode layer and a gate dielectric layer on one side of a flexible substrate;

[0030] 2) Deposit a metal oxide channel layer on the surface of the gate dielectric layer;

[0031] 3) Deposit a source electrode and a drain electrode on the surface of the metal oxide channel layer;

[0032] 4) Coat a piezoelectric layer material dispersion on the surface of the metal oxide channel layer, and then dry it to form a piezoelectric layer, thus obtaining a flexible pressure sensor based on a metal oxide thin film transistor.

[0033] Preferably, the flexible substrate in step 1) has been pretreated, and the pretreatment includes the following operations: bonding the flexible substrate to a glass substrate through a pressure-sensitive adhesive, then performing water washing, then ultrasonically cleaning with alcohol and acetone for 15 min to 35 min each in sequence, and then drying.

[0034] Preferably, the method for depositing the source electrode in step 3) is one of vacuum thermal evaporation, magnetron sputtering, and plasma-enhanced chemical vapor deposition.

[0035] Preferably, the method for depositing the drain electrode in step 3) is one of vacuum thermal evaporation, magnetron sputtering, and plasma-enhanced chemical vapor deposition.

[0036] Preferably, the solvent in the piezoelectric layer material dispersion liquid in step 4) is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, chloroform, dichloromethane, and ethanol.

[0037] Preferably, the coating method in step 4) is spin coating.

[0038] A pressure sensor array substrate, which includes the above-mentioned flexible pressure sensor based on a metal oxide thin film transistor.

[0039] A pressure sensor integration system, which includes the above-mentioned flexible pressure sensor based on a metal oxide thin film transistor.

[0040] The working principle of the flexible pressure sensor based on a metal oxide thin film transistor of the present invention: Under the action of pressure, the piezoelectric layer in the flexible pressure sensor based on a metal oxide thin film transistor will deform to generate polarized charges, thereby affecting the carrier distribution in the metal oxide channel layer. The magnitude of the pressure is proportional to the channel current. Therefore, the channel current of the metal oxide thin film transistor can be used as the output signal of the sensor to achieve pressure detection.

[0041] The beneficial effects of the present invention are as follows: The flexible pressure sensor based on a metal oxide thin film transistor of the present invention has excellent electrical properties, good flexibility, high sensitivity, easy integration, and its preparation process is simple and low-cost. It is suitable for the production of large-scale sensor arrays and has very broad application prospects in the fields of flexible touch screens, human-computer interaction, and electronic skin.

[0042] Specifically:

[0043] 1) The flexible pressure sensor based on a metal oxide thin film transistor of the present invention is prepared by introducing a piezoelectric layer into the channel of the metal oxide thin film transistor. The introduction of the piezoelectric layer endows the metal oxide thin film transistor with excellent pressure detection performance, enabling the flexible pressure sensor based on a metal oxide thin film transistor to simultaneously serve as the pressure sensing part and the transistor of the backend processing circuit, which is beneficial to the preparation of a highly integrated pressure sensor system and is suitable for application environments that require large-area and high-precision sensing;

[0044] 2) The flexible pressure sensor based on a metal oxide thin film transistor of the present invention has good flexibility, high mobility, high on-off ratio, and good stability, and has very broad application prospects in the fields of flexible touch screens, human-computer interaction, and electronic skin;

[0045] 3) The flexible pressure sensor based on a metal-oxide thin-film transistor of the present invention includes a piezoelectric layer made of a piezoelectric polymer, ZnO nanoparticles, and MXene nanosheets, and the surface of the piezoelectric layer has a convex micro-nano structure, enabling the flexible pressure sensor to maintain high sensitivity and a fast response speed within the low-pressure linear region range, reducing the hysteresis of the flexible pressure sensor. At the same time, the introduction of the piezoelectric layer does not damage the transistor characteristics, and it can prevent the erosion of water and oxygen, making the entire device have good atmospheric stability. In addition, the piezoelectric layer itself also has high chemical stability, thermal stability, and excellent mechanical durability;

[0046] 4) The preparation raw materials of the flexible pressure sensor based on a metal-oxide thin-film transistor of the present invention are simple and easy to obtain, and its preparation method is simple, safe, and easy to achieve large-area array processing and industrial-scale mass production. Description of the Drawings

[0047] Figure 1 It is a schematic structural diagram of the flexible pressure sensor based on a metal-oxide thin-film transistor in the present invention.

[0048] Description of the drawing reference numerals: 100, flexible substrate; 200, gate electrode layer; 300, gate dielectric layer; 400, metal-oxide channel layer; 500, source electrode; 600, drain electrode; 700, piezoelectric layer.

[0049] Figure 2 It is an SEM image of the piezoelectric layer in Example 1.

[0050] Figure 3 It is a schematic circuit structure diagram of the flexible pressure sensor based on a metal-oxide thin-film transistor in the present invention.

[0051] Figure 4 It is a working principle diagram of the flexible pressure sensor based on a metal-oxide thin-film transistor in the present invention.

[0052] Figure 5 It is a transfer characteristic curve of the flexible pressure sensor based on a metal-oxide thin-film transistor in Example 1.

[0053] Figure 6 It is a sensitivity test result diagram of the flexible pressure sensors based on metal-oxide thin-film transistors in Example 1, Comparative Example 1, and Comparative Example 2.

[0054] Figure 7 It is a current-response time relationship curve of the flexible pressure sensor based on a metal-oxide thin-film transistor in Example 1. Detailed Embodiments

[0055] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0056] Example 1:

[0057] A flexible pressure sensor based on a metal-oxide thin-film transistor (the structural schematic diagram is as shown Figure 1 ), which is composed of a flexible substrate 100, a gate electrode layer 200, a gate dielectric layer 300, a metal-oxide channel layer 400, a source electrode 500, a drain electrode 600, and a piezoelectric layer 700; the flexible substrate 100, the gate electrode layer 200, the gate dielectric layer 300, and the metal-oxide channel layer 400 are stacked in sequence from bottom to top; the source electrode 500, the drain electrode 600, and the piezoelectric layer 700 are disposed on the side of the metal-oxide channel layer 400 away from the gate dielectric layer 300; the flexible substrate 100 is a flexible polyimide substrate with a thickness of 20 μm; the gate electrode layer 200 is an Al-Nd layer with a thickness of 150 nm; the gate dielectric layer 300 is an aluminum neodymium oxide layer with a thickness of 200 nm; the metal-oxide channel layer 400 is an indium tin zinc oxide layer with a thickness of 60 nm, the channel length is 300 μm, and the channel width is 300 μm; the source electrode 500 is a polycrystalline indium tin oxide layer with a thickness of 100 nm; the drain electrode 600 is a polycrystalline indium tin oxide layer with a thickness of 100 nm; the piezoelectric layer 700 is composed of polyvinylidene fluoride (number-average molecular weight is 150,000), ZnO nanoparticles, and Ti 2 CT x -MXene nanosheets, and the total mass percentage content of ZnO nanoparticles and Ti 2 CT x -MXene nanosheets is 30.6%, and the mass ratio of ZnO nanoparticles to Ti 2 CT x -MXene nanosheets is 10:1. The shape of the ZnO nanoparticles is spherical, the particle size is 320 nm to 520 nm, and the sheet diameter of Ti 2 CT x -MXene nanosheets is 0.2 μm to 1 μm; the surface of the piezoelectric layer 700 has a convex micro-nano structure; the thickness of the piezoelectric layer 700 is 15 μm.

[0058] The preparation method of the above flexible pressure sensor based on a metal-oxide thin-film transistor is as follows:

[0059] 1) Bond a flexible polyimide substrate with a size specification of 1 cm × 1 cm × 20 μm to a glass substrate with a thickness of 0.7 mm using a pressure-sensitive adhesive, then wash it with deionized water, ultrasonically clean it with alcohol and acetone for 15 min each in turn, then place it in a vacuum drying oven and bake it at 85 °C for 1 h. Then, deposit an Al-Nd alloy film with a thickness of 150 nm on the surface of the flexible polyimide substrate (the side away from the glass substrate) by DC magnetron sputtering, and pattern it by photolithography to form a gate electrode layer. Then, place the device with the prepared gate electrode layer as the anode and a stainless steel plate as the cathode into an ethylene glycol solution of ammonium tartrate with a concentration of 0.02 mol / L, and apply a constant current between the anode and the cathode to make the voltage between the anode and the cathode linearly increase with time until the voltage reaches 100 V, and then keep the voltage constant until the current between the anode and the cathode decreases to 0.001 mA / cm 2 , deposit an aluminum neodymium oxide film with a thickness of 200 nm on the surface of the gate electrode layer, and then pattern the aluminum neodymium oxide film to form a gate dielectric layer;

[0060] 2) Fix the device with the prepared gate dielectric layer in a patterned metal mask. By simultaneously using a polycrystalline indium tin oxide target controlled by a DC power supply magnetron sputtering and a polycrystalline zinc oxide target controlled by an RF power supply magnetron sputtering, deposit an indium tin zinc oxide film with a thickness of 60 nm. The power during sputtering of the polycrystalline indium tin oxide target is 100 W, and the mass ratio of In 2 O 3 and SnO 2 in the polycrystalline indium tin oxide target is 9:1. The power during sputtering of the polycrystalline zinc oxide target is 130 W. The sputtering chamber pressure is set to 0.5 Pa, the gas atmosphere is oxygen and argon, and the flow rates are set to 6 sccm and 10 sccm respectively. The sputtering temperature is set to 30 °C, and the sputtering time is set to 5 min to form a metal oxide channel layer;

[0061] 3) Fix the device with the prepared metal oxide channel layer in a patterned metal mask. By DC power supply magnetron sputtering of a polycrystalline indium tin oxide target, deposit polycrystalline indium tin oxide films with a thickness of 100 nm at both ends of the metal oxide channel layer as source and drain electrodes respectively. The formed electrodes make the width of the channel 300 μm and the length 300 μm (width-to-length ratio is 1:1). The sputtering chamber pressure is set to 0.5 Pa, the gas atmosphere is oxygen and argon, and the flow rates are set to 3 sccm and 10 sccm respectively. The sputtering temperature is set to 30 °C, the sputtering power of the polycrystalline indium tin oxide target is set to 100 W, and the sputtering time is set to 10 min. Then, place the obtained device on a hot stage, set the temperature to 350 °C, and anneal it in an air atmosphere for 3 h;

[0062] 4) Disperse 500 mg of polyvinylidene fluoride and 200 mg of ZnO nanoparticles in 4.3 g of N,N-dimethylformamide (DMF), then add 20 mg of Ti 2 CT x -MXene nanosheets, stir at 45 °C for 2 h to prepare a piezoelectric layer material dispersion, and then use a spin coater to spin coat the piezoelectric layer material dispersion on the surface (in the middle, between the source electrode and the drain electrode) of the metal oxide channel layer. The spin coating parameters are a rotation speed of 500 r / min for 45 s, and then cure at 90 °C on a hot stage for 10 min to form a piezoelectric layer, thus obtaining a flexible pressure sensor based on a metal oxide thin film transistor.

[0063] Note:

[0064] The preparation method of the ZnO nanoparticles in this example is as follows: Add 1.5 g of Zn(NO 3 ) 2 ·6H 2 O, 0.71 g of hexamethylenetetramine, and 50 mL of deionized water into a hydrothermal reaction kettle, react at 95 °C for 4 h, then add deionized water and centrifuge 4 times, and take the precipitate obtained by centrifugation for drying to obtain ZnO nanoparticles.

[0065] The preparation method of the Ti 2 CT x -MXene nanosheets in this example is as follows: Disperse Ti 2 CT x -MXene with deionized water to make a Ti 2 CT x -MXene dispersion with a concentration of 10 mg / mL, and then place it in a vacuum freeze dryer and freeze dry at -40 °C for 48 h to obtain Ti 2 CT x -MXene nanosheets.

[0066] The scanning electron microscope (SEM) image of the piezoelectric layer (surface) in this example is as Figure 2 shown.

[0067] It can be seen from Figure 2 that: The surface of the piezoelectric layer has a granular protrusion morphology, which is mainly caused by the composite of multi-component materials, and its thickness is about 15 μm.

[0068] The circuit structure schematic diagram of the flexible pressure sensor (single) based on a metal oxide thin film transistor in this example is as Figure 3 shown.

[0069] It can be seen from Figure 3It can be known that: the piezoelectric layer is coupled to the back channel of a metal-oxide thin-film transistor (MO TFT). The integration of the metal-oxide thin-film transistor and the piezoelectric sensing unit can not only convert external mechanical stimuli into electrical signals, but also amplify weak electrical signals for detection. At the same time, the piezoelectric charges generated by the piezoelectric layer can regulate the TFT channel current, thereby obtaining the pressure information at the corresponding position.

[0070] The working principle diagram of the flexible pressure sensor based on the metal-oxide thin-film transistor in this embodiment is as Figure 4 shown.

[0071] It can be known from Figure 4 that: when a certain weight is applied to the piezoelectric layer on the top of the device, the piezoelectric layer is compressed, and the internal deformed dipole self-polarization generates polarization charges. These charges accumulate to form a piezoelectric potential, generating a positive potential at the bottom of the piezoelectric layer, thereby attracting electrons in the channel layer. Therefore, some additional positive gate voltage is required in the TFT to maintain its drain current relative to the normal state, which will lead to an increase in the threshold voltage. When the external stress is released, the polarized dipoles attempt to return to the initial state, the accumulated charges move in the opposite direction, and an opposite electric potential is generated in the piezoelectric layer.

[0072] Comparative Example 1:

[0073] A flexible pressure sensor based on a metal-oxide thin-film transistor is completely the same as the flexible pressure sensor based on the metal-oxide thin-film transistor in Example 1, except that the composition of the piezoelectric layer is adjusted to "polyvinylidene fluoride".

[0074] Comparative Example 2:

[0075] A flexible pressure sensor based on a metal-oxide thin-film transistor is completely the same as the flexible pressure sensor based on the metal-oxide thin-film transistor in Example 1, except that the composition of the piezoelectric layer is adjusted to "polyvinylidene fluoride and ZnO nanoparticles (the mass ratio of polyvinylidene fluoride to ZnO nanoparticles is 5:1)".

[0076] Performance test:

[0077] 1) Use a Keysight B1500A semiconductor parameter analyzer to test the electrical performance of the flexible pressure sensor based on the metal-oxide thin-film transistor in Example 1. Set V ds to 0.1V and 5.1V respectively, and set V gs from -10V to 20V. The obtained transfer characteristic curve is as Figure 5 shown.

[0078] It can be known from Figure 5It can be seen that the flexible pressure sensor based on metal oxide thin film transistors in Example 1 has good electrical properties, with a mobility of 18.16 cm 2 / V·s, a threshold voltage of 0.97 V, a subthreshold swing of 110 mV / dec, a switching ratio of 2.43×10 7 , and a trap state density of 2.04×10 12 cm -2 .

[0079] 2) The normalized current response (current change rate) and the applied pressure (the applied pressures are 0 kPa, 0.1 kPa, 0.15 kPa, 0.21 kPa, 0.25 kPa, 0.51 kPa, and 1.02 kPa respectively) of the flexible pressure sensors based on metal oxide thin film transistors in Example 1, Comparative Example 1, and Comparative Example 2 were tested using a Keysight B1500A semiconductor parameter analyzer. The normalized response is defined as the ratio of the change in drain current (ΔI) to the base current (I base ) without applying pressure. Record the corresponding current change rates under different pressures, and perform fitting on the obtained curves to obtain the corresponding sensitivity information. The sensitivity test results of the obtained flexible pressure sensors are as shown in Figure 6 .

[0080] It can be seen from Figure 6 that as the pressure increases, the responses of the flexible pressure sensors based on metal oxide thin film transistors in Example 1, Comparative Example 1, and Comparative Example 2 all increase linearly and then gradually saturate at higher pressures. By performing fitting on the obtained curves, the sensitivities of the flexible pressure sensors based on metal oxide thin film transistors in Example 1, Comparative Example 1, and Comparative Example 2 in the linear region are 3.53 kPa -1 , 0.56 kPa -1 , and 1.87 kPa -1 respectively, indicating that the piezoelectric layer made of piezoelectric polymer, ZnO nanoparticles, and MXene nanosheets used in the present invention can significantly improve the sensitivity of the flexible pressure sensor based on metal oxide thin film transistors.

[0081] 3) The current signal of the flexible pressure sensor based on metal oxide thin film transistors in Example 1 was collected under dynamic loading conditions, and the test was carried out under the condition of no bottom gate bias (V bg = 0 V) and V ds = 5.1 V. A 1 g weight (corresponding to a pressure of 1.02 kPa) was applied, and the current-response time relationship curve obtained is as shown in Figure 7 .

[0082] It can be seen from Figure 7It can be seen that after applying weight, the drain current (I ds ) immediately increases, and after removing the weight, the drain current (I ds ) returns to the initial value again. The response and recovery times of the flexible pressure sensor are measured to be 125 ms and 95 ms respectively. This rapid response is attributed to the direct piezoelectric effect of the piezoelectric layer and the strong adhesion between the channel layer and the piezoelectric layer, ensuring that pressure changes can be effectively transmitted to the device.

[0083] Example 2:

[0084] A flexible pressure sensor based on a metal-oxide thin-film transistor, except that when preparing, the dosage of Ti 2 CT x -MXene nanosheets is adjusted from "20 mg" to "10 mg" in step 4), and the rest is exactly the same as in Example 1.

[0085] After testing (the testing method is the same as that in Example 1), the sensitivity of the flexible pressure sensor based on the metal-oxide thin-film transistor in this example is 3.15 kPa -1 , and the sensitivity is high.

[0086] Example 3:

[0087] A flexible pressure sensor based on a metal-oxide thin-film transistor, except that when preparing, the dosage of Ti 2 CT x -MXene nanosheets is adjusted from "20 mg" to "30 mg" in step 4), and the rest is exactly the same as in Example 1.

[0088] After testing (the testing method is the same as that in Example 1), the sensitivity of the flexible pressure sensor based on the metal-oxide thin-film transistor in this example is 2.31 kPa -1 , and the sensitivity is high.

[0089] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A flexible pressure sensor based on metal oxide thin film transistor, characterized in that: The composition includes a flexible substrate, a gate electrode layer, a gate dielectric layer and a metal oxide channel layer stacked in sequence, and also includes a source electrode, a drain electrode and a piezoelectric layer arranged on the side of the metal oxide channel layer away from the gate dielectric layer; the piezoelectric layer is composed of piezoelectric polymers, ZnO nanoparticles and MXene nanosheets; the surface of the piezoelectric layer has a protruding micro-nano structure.

2. The flexible pressure sensor based on metal oxide thin film transistor according to claim 1, characterized in that: The flexible substrate is one of a flexible polycarbonate substrate, a flexible polydimethylsiloxane substrate, a flexible polymethyl methacrylate substrate, a flexible polyethylene terephthalate substrate, and a flexible polyimide substrate; the gate electrode layer is one of an Al layer, an Al-Nd layer, and an ITO layer; the gate dielectric layer is one of a silicon dioxide layer, an aluminum oxide layer, and an aluminum-neodymium oxide layer; the metal oxide channel layer is one of an indium zinc oxide layer, a tin zinc oxide layer, an indium tin zinc oxide layer, an indium gallium zinc oxide layer, and a zirconium indium tin zinc oxide layer.

3. The flexible pressure sensor based on metal oxide thin film transistor according to claim 1 or 2, characterized in that: The thickness of the flexible substrate is 15 μm to 25 μm; the thickness of the gate electrode layer is 100 nm to 200 nm; the thickness of the gate dielectric layer is 180 nm to 280 nm; the thickness of the metal oxide channel layer is 50 nm to 100 nm, the channel length is 200 μm to 500 μm, and the channel width is 200 μm to 500 μm.

4. The flexible pressure sensor based on metal oxide thin film transistor according to claim 1, characterized in that: The source electrode is one of an ITO electrode, an Al electrode, a Cu electrode, and an Au electrode; the drain electrode is one of an ITO electrode, an Al electrode, a Cu electrode, and an Au electrode; the thickness of the source electrode is 80nm to 180nm; the thickness of the drain electrode is 80nm to 180nm.

5. The flexible pressure sensor based on metal oxide thin film transistor according to claim 1, characterized in that: The total mass percentage of the ZnO nanoparticles and the MXene nanosheets in the piezoelectric layer is 25% to 35%; the mass ratio of the ZnO nanoparticles to the MXene nanosheets in the piezoelectric layer is 5 to 20:

1.

6. The flexible pressure sensor based on metal oxide thin film transistor according to claim 1 or 5, characterized in that: The piezoelectric polymer is at least one of polyvinylidene fluoride, poly(vinylidene fluoride-trifluoroethylene), and poly(vinylidene fluoride-hexafluoropropylene); the ZnO nanoparticles are in the shape of at least one of sphere, prism, and flower, and the particle size is 320nm to 520nm; the MXene nanosheets are Ti2CT x -MXene nanosheets, Ta4C3T x -MXene nanosheets, Nb2CT x -MXene nanosheets, V2CT x -MXene nanosheets, Nb4C3T x -MXene nanosheets, Mo2CT x -At least one of MXene nanosheets; the MXene nanosheet has a sheet diameter of 0.2 μm to 1 μm.

7. The flexible pressure sensor based on metal oxide thin film transistor according to claim 1 or 5, characterized in that: The thickness of the piezoelectric layer is 5 μm to 20 μm.

8. A method for preparing a flexible pressure sensor based on a metal oxide thin film transistor according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) depositing a gate electrode layer and a gate dielectric layer in sequence on a single surface of a flexible substrate; 2) depositing a metal oxide channel layer on the surface of the gate dielectric layer; 3) depositing a source electrode and a drain electrode on the surface of the metal oxide channel layer; 4) A piezoelectric layer material dispersion is coated on the surface of the metal oxide channel layer, and then dried to form a piezoelectric layer, thereby obtaining a flexible pressure sensor based on a metal oxide thin film transistor.

9. A pressure sensor array substrate, characterized in that: A flexible pressure sensor based on a metal oxide thin film transistor comprising any one of claims 1 to 7.

10. A pressure sensor integrated system, characterized in that: A flexible pressure sensor based on a metal oxide thin film transistor comprising any one of claims 1 to 7.

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