A flexible pressure sensor with adjustable sensitivity of suspended gate transistor type and a preparation method thereof

Abstract

The application discloses a flexible pressure sensor with adjustable sensitivity in a suspended gate transistor type and a preparation method thereof, which comprises a flexible electrode substrate, a semiconductor layer and a pressure sensitive layer as a gate electrode; the flexible electrode substrate comprises an active source-drain electrode and a conductive channel; the semiconductor layer comprises an active layer and a gasket, the active layer completely covers the source-drain electrode and the conductive channel and is in physical contact with the source-drain electrode; the gasket is arranged on the active layer and is arranged on both sides of the conductive channel correspondingly; the pressure sensitive layer is located on the gasket to form a suspended gate structure; when the flexible pressure sensor is subjected to external pressure, the pressure sensitive layer is deformed to change the charge amount of the active layer, so that the external pressure is sensitively detected; the sensitivity of the flexible pressure sensor is adjusted by adjusting the source-drain voltage and the gate voltage; the application has the advantages of low cost, simple process and the like and can be widely applied in the field of flexible pressure sensors.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pressure sensors, specifically a suspended gate transistor type flexible pressure sensor with adjustable sensitivity and its preparation method. BACKGROUND

[0002] Pressure sensor technology is widely used in various fields, including wearable devices, industrial automation, medical health monitoring, and consumer electronics. By sensing the physical pressure applied from the outside world, these changes in force are converted into electrical signals, helping devices monitor the environment or user's physiological conditions in real time. In wearable devices, pressure sensors can detect user's vital signs such as breathing, gait, etc.; in industrial automation, they are used for precise load and pressure control; in modern medical devices, pressure sensors are also used to monitor patients' blood pressure and breathing, and other key health parameters in real time. With the rise of flexible electronics and Internet of Things devices, pressure sensor technology is also advancing to meet the requirements of sensitivity, accuracy, response time and working stability in increasingly complex application scenarios.

[0003] The current mainstream types of pressure sensors include piezoelectric, piezoresistive and capacitive, etc. The sensitivity of these devices is usually determined during the design and manufacturing stage, making it difficult to adjust during actual use, limiting their application in medical health monitoring and flexible electronic devices, etc. There are a large number of studies that improve the performance of pressure sensors by constructing microstructures (such as pyramidal, columnar, porous structure, etc.), but these processes often have the problems of high complexity, high equipment cost and high energy consumption. In addition, most existing flexible pressure sensors have insufficient sensitivity, limited detection range, and are difficult to effectively identify weak physiological signals. Therefore, it is necessary to provide a new type of pressure sensor that can balance high sensitivity, wide detection range and simplify the manufacturing process. SUMMARY

[0004] The present application belongs to the technical field of pressure sensors, specifically a suspended gate transistor type flexible pressure sensor with adjustable sensitivity and its preparation method.

[0005] Technical solution: A flexible pressure sensor with adjustable sensitivity of suspended gate transistor type, comprising: a flexible electrode substrate, a semiconductor layer and a pressure sensitive layer as a gate; the flexible electrode substrate comprises an active drain electrode and a conductive channel; the semiconductor layer comprises an active layer and a gasket, the active layer completely covers the source-drain electrode and the conductive channel, and is in physical contact with the source-drain electrode; the gasket is arranged on the active layer, and the gasket is arranged on the two sides of the conductive channel; the pressure sensitive layer is located on the gasket, forming a suspended gate structure.

[0006] When the flexible pressure sensor is subjected to external pressure, the pressure sensitive layer deforms, changes the carrier mobility of the active layer, and realizes sensitive detection of external pressure.

[0007] By adjusting the source-drain voltage and the gate voltage, the sensitivity of the flexible pressure sensor is adjusted.

[0008] Further, the flexible electrode substrate further comprises: a flexible substrate, and the source-drain electrode is embedded in the flexible substrate to form the flexible electrode substrate.

[0009] Further, the active layer is a poly(3-hexylthiophene) film obtained by self-assembly.

[0010] Further, the gasket is made of polydimethylsiloxane material.

[0011] Further, the pressure sensitive layer is an ionic gel layer.

[0012] Further, it further comprises a packaging layer, and the packaging layer covers the pressure sensitive layer.

[0013] The application discloses a preparation method of a flexible pressure sensor with adjustable sensitivity of suspended gate transistor type.

[0014] Step 1: The polyimide mask is attached to the glass substrate, then the silver nanowire dispersion liquid is dropped and coated, after solidification, the polyimide mask is removed, and the source-drain electrode and the transistor conductive channel are formed.

[0015] Step 2: Mix the main agent dimethylsiloxane and the crosslinking agent, spin-coat on the source-drain electrode and heat to solidify, and form the flexible electrode substrate;

[0016] Step 3: Poly(3-hexylthiophene) is dissolved in toluene and dropped on the water surface to form a nanofilm, and the formed nanofilm is transferred to the source-drain electrode to completely cover the conductive channel, forming an active layer;

[0017] Step 4: Prepare a polydimethylsiloxane gasket, cut it into small pieces, and arrange it on the active layer, and the gasket is arranged on the two sides of the conductive channel;

[0018] Step 5: Mix the polymer P(VDF-HFP), ionic liquid [EMIM][TFSI] and acetone, spin-coat on the gasket, heat and cure to form a pressure sensitive layer;

[0019] Step 6: Mix the main agent dimethylsiloxane and the crosslinking agent, spin-coat into an encapsulation layer, and place it above the pressure sensitive layer to cover the ionic gel.

[0020] Advantages: Compared with the prior art, the present application has the following advantages:

[0021] (1) The present application designs a suspended gate transistor structure, which can control the sensitivity of the sensor by the gate voltage and the source-drain voltage respectively. The suspended gate design not only improves the detection accuracy of the sensor under different pressures, but also dynamically adjusts the sensitivity of the sensor by independently adjusting the gate voltage and the source-drain voltage. Through this method, the pressure sensor of the present application can flexibly adapt to various application scenarios without changing the material and microstructure to realize the optimization of accuracy and sensitivity.

[0022] (2) The present application further enhances the stability and durability of the device by designing the encapsulation layer, making it suitable for high-demand applications in flexible electronic devices and wearable devices.

[0023] (3) The method of the present application has the advantages of low cost and simple process, and can be widely applied in the field of flexible pressure sensors. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A structure diagram of a suspended gate transistor type flexible pressure sensor with adjustable sensitivity proposed by the present application;

[0025] Figure 2 A suspended gate transistor type flexible pressure sensor with adjustable sensitivity and its dynamic response diagram proposed by the present application;

[0026] Figure 3 A response diagram of the suspended gate transistor type flexible pressure sensor proposed by the present application to different pressures;

[0027] Figure 4 A diagram showing the influence of source-drain voltage on sensitivity;

[0028] Figure 5 A diagram showing the influence of bias voltage on sensitivity. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description, in conjunction with the accompanying drawings and embodiments, will further illustrate the present invention's proposed flexible pressure sensor with adjustable sensitivity based on a floating gate transistor and its fabrication method.

[0030] Example 1:

[0031] This embodiment proposes a flexible pressure sensor with adjustable sensitivity based on a floating gate transistor, such as... Figure 1 As shown, it mainly includes: a flexible electrode substrate, a semiconductor layer, and a pressure-sensitive layer; in the flexible electrode substrate, source and drain electrodes are formed by silver nanowires, the semiconductor layer is obtained by self-assembly to obtain a uniform thin film, and then transferred between the source and drain electrodes, and ion gel is used as the pressure-sensitive layer; in this embodiment, a gate material composed of ion gel is covered on the flexible electrode substrate and the semiconductor layer to form a floating gate structure. The floating gate structure is isolated from the semiconductor layer by the ion gel, and gate control operation is realized in a non-contact state to improve the adjustability of sensitivity.

[0032] Now combined Figure 1 The structure of the flexible pressure sensor proposed in this embodiment will be further described below. The flexible electrode substrate includes a flexible substrate and source / drain electrodes; the semiconductor layer includes an active layer covering the source / drain electrodes and a pad built on the active layer, with the pressure-sensitive layer located on the pad. This embodiment optimizes the pressure transmission path by rationally designing the physical contact between the source / drain electrodes and the active layer, and by combining the pad. When the sensor is subjected to external pressure, the pressure-sensitive layer deforms, thereby changing the charge of the active layer to achieve sensitive detection of external pressure.

[0033] This embodiment also includes an encapsulation layer, such as... Figure 2 As shown, this encapsulation layer not only reduces the dynamic response time of the device, but also improves the stability and durability of the device (e.g., Figure 3 (As shown), it is suitable for various types of skin-friendly smart electronic devices. Figure 4 and Figure 5 The effects of source-drain voltage and bias voltage on sensitivity are described separately. It can be seen that the sensitivity can be adjusted by adjusting the source-drain voltage and gate voltage in this embodiment. It has high sensitivity, low power consumption and good flexibility, and is suitable for pressure sensing applications in wearable devices and flexible electronics.

[0034] In this embodiment, the flexible substrate and the encapsulation layer are made of polydimethylsiloxane (PDMS), but are not limited to PDMS. The mass ratio of the main agent dimethylsiloxane to the crosslinking agent used in the flexible substrate is 10:1, and the mass ratio of the main agent dimethylsiloxane to the crosslinking agent used in the encapsulation layer is 20:1.

[0035] In this embodiment, the material of the source-drain electrode is silver nanowire material, but is not limited to silver nanowire material, the source-drain electrode is embedded in polydimethylsiloxane (PDMS) to prepare an AgNWs / PDMS integrated substrate.

[0036] In this embodiment, the active layer adopts poly(3-hexylthiophene) (P3HT) material, but is not limited to poly(3-hexylthiophene) (P3HT) material.

[0037] In this embodiment, the pressure-sensitive layer adopts ionic gel which is mixed by polymer P(VDF-HFP) and electrolyte solution [EMIM][TFSI], but is not limited to ionic gel.

[0038] Embodiment 2:

[0039] This embodiment proposes a preparation method of a flexible pressure sensor with adjustable sensitivity in the form of a suspended gate transistor as proposed in embodiment 1, which mainly includes the following steps:

[0040] Step 1: Preparation of source-drain electrode: polyimide mask is attached to the glass substrate, then 0.5wt% silver nanowire dispersion is dropped and heated at 50°C, repeated three times, and cured at 70°C for 20 min. The polyimide mask is removed to form the source-drain electrode and the transistor conductive channel.

[0041] Step 2: Preparation of flexible substrate: polydimethylsiloxane (PDMS) with a mass ratio of main agent dimethylsiloxane to crosslinking agent of 10:1 is prepared, placed for 30 min to completely disappear the bubbles, and spin-coated on the source-drain electrode prepared in step 1, heated at 90°C for 1 h to completely cure the polydimethylsiloxane (PDMS), and form the flexible substrate.

[0042] Step 3: Preparation of active layer: poly(3-hexylthiophene) (P3HT) is dissolved in toluene to form a polymer solution, which is then added dropwise to the water surface. Since toluene is not miscible with water, the polymer solution will quickly spread on the water surface, and thus self-assemble into a poly(3-hexylthiophene) (P3HT) nanofilm at the water / air interface. The poly(3-hexylthiophene) (P3HT) nanofilm is then transferred to the source-drain electrode in (2) to completely cover the channel, forming a high-efficiency conductive channel, and then air-dried to form the active layer.

[0043] Step 4: Preparation of gasket: polydimethylsiloxane (PDMS) with a mass ratio of main agent dimethylsiloxane to crosslinking agent of 10:1 is prepared, placed for 30 min to completely disappear the bubbles, and spin-coated on the glass substrate, heated at 90°C for 1 h to completely cure the polydimethylsiloxane (PDMS), and then cut into a size of 0.4 cm x 0.2 cm and transferred to both sides of the conductive channel in (3) with a gasket spacing of 0.3 cm.

[0044] Step 5: Preparation of pressure sensitive layer: copolymer P(VDF-HFP), ionic liquid [EMIM][TFSI] and acetone are mixed in a mass ratio of 1:4:7, heated at 70°C for 2h to make the ionic liquid uniformly dispersed in the interlayer of the copolymer, after the bubbles completely disappear, spin coating on the glass substrate, 70°C heating and curing for 24h, cutting into 1cm×0.2cm and transferring to the gasket built in (4), the ionic gel is suspended above the conductive channel and cannot contact the active layer or electrode, forming the pressure sensitive layer.

[0045] Step 6: Preparation of encapsulation layer: polydimethylsiloxane (PDMS) with a mass ratio of 20:1 of main agent dimethylsiloxane and crosslinking agent is prepared, spin coating on the glass substrate after placing for 30min to make the bubbles completely disappear, 90°C heating for 1h to make the PDMS completely cured, spin coating into an encapsulation layer, cutting into 0.8cm×0.2cm and placing on the ionic gel built in (5), the encapsulation layer does not completely cover the pressure sensitive layer to improve the stability and recycling ability of the device.

[0046] Example 3:

[0047] The present embodiment proposes a preparation method of a flexible pressure sensor with adjustable sensitivity in a suspended gate transistor mode, comprising the following steps:

[0048] (1) Attach a polyimide mask to the glass substrate, then drop 0.5wt% silver nanowire dispersion liquid, continuously heat at 50°C, drop three times repeatedly, cure at 70°C for 20min, tear off the polyimide mask, and form the source-drain electrode and transistor conductive channel.

[0049] (2) Mix the main agent dimethylsiloxane and the auxiliary crosslinking agent in a mass ratio of 10:1, spin coating the bubble-free PDMS on the prepared source-drain electrode at 500rpm, 90°C heating and curing for 1h, and tearing off the cured PDMS / AgNWs to obtain a flexible and stretchable source-drain electrode.

[0050] (3) Drop a small amount of 10mg / ml P3HT toluene solution on the calm water surface, after the solvent evaporates, the P3HT self-assembled film floats on the water surface, transfer to the flexible electrode, and naturally air dry for use.

[0051] (4) Attach 0.4cm×0.3cm PDMS (mass ratio of main agent dimethylsiloxane to auxiliary crosslinking agent is 10:1) gaskets on both sides of the source-drain channel, and the distance between the two gaskets is 0.3cm.

[0052] (5) The copolymer P(VDF-HFP), ionic liquid [EMIM][TFSI] and acetone are mixed in a mass ratio of 1:4:7, heated and stirred at 70°C for 2h to make the ionic liquid uniformly dispersed in the interstices of the copolymer. After the bubbles completely disappear, spin coating is performed on a glass substrate at 500 rpm, and the ionic gel is heated and cured at 70°C for 24h. The ionic gel is cut into 1cm x 0.3cm and transferred to the gasket. The ionic gel is suspended above the conductive channel and cannot contact the active layer and the electrode.

[0053] (6) The main agent dimethylsiloxane and the auxiliary crosslinking agent are mixed and stirred uniformly in a mass ratio of 20:1. The spin coater is used to spin coat on a glass substrate at 500 rpm, and the sample is heated and cured at 90°C for 1h. The sample is cut into 0.8cm x 0.3cm and transferred to the ionic gel. The ionic gel above the channel is completely covered.

[0054] (7) The device is fixed on a 6-inch probe station, a voltage of -0.5V is applied to the source and drain electrodes, and different mechanical external forces are applied.

[0055] The pressure sensor prepared according to the above steps has a low pressure range sensitivity of 0.1859kPa -1 and a high pressure range sensitivity of 1.3769kPa -1 .

[0056] Example 4:

[0057] The present embodiment provides a preparation method of a flexible pressure sensor with adjustable sensitivity in a suspended gate transistor mode, comprising the following steps:

[0058] (1) A polyimide mask is attached to a glass substrate, and then 0.5wt% silver nanowire dispersion liquid is drop-coated. The sample is heated at 50°C for 20min, and the polyimide mask is removed to form source and drain electrodes and a transistor conductive channel.

[0059] (2) The main agent dimethylsiloxane and the auxiliary crosslinking agent are mixed and stirred uniformly in a mass ratio of 10:1. Bubble-free PDMS is spin-coated on the prepared source and drain electrodes at 500 rpm, and the sample is heated and cured at 90°C for 1h. The cured PDMS / AgNWs are peeled off to obtain a flexible and stretchable source and drain electrode.

[0060] (3) A small amount of 10mg / ml P3HT toluene solution is dropped on the calm water surface. After the solvent evaporates, the P3HT self-assembled film floats on the water surface and is transferred to the flexible electrode. The sample is naturally air-dried and can be used.

[0061] (4) Attach 0.4 cm x 0.3 cm size polyimide (main agent dimethylsiloxane and auxiliary crosslinking agent mass ratio of 10:1) gasket on both sides of the source-drain channel, the distance between the two gaskets is 0.3 cm.

[0062] (5) Mix copolymer P(VDF-HFP), ionic liquid [EMIM][TFSI] and acetone at a mass ratio of 1:4:7, heat and stir at 70°C for 2h to make the ionic liquid uniformly dispersed in the interstices of the copolymer. After the bubbles completely disappear, spin coating on the glass substrate at 500 rpm, heat and solidify at 70°C for 24h, cut into 1 cm x 0.3 cm and transfer to the gasket. The ionic gel should be suspended above the conductive channel and cannot contact the active layer and the electrode.

[0063] (6) Mix the main agent dimethylsiloxane and the auxiliary crosslinking agent at a mass ratio of 20:1, stir uniformly, spin coating on the glass substrate at 500 rpm using a spin coater, heat and solidify at 90°C for 1h, cut into 0.8 cm x 0.3 cm size and then transfer to the ionic gel, completely covering the ionic gel above the channel.

[0064] (7) Fix the device on the probe station, apply a voltage of -1.0V on the source-drain electrode, and apply different mechanical external force.

[0065] The pressure sensor prepared according to the above steps has a low pressure range sensitivity of 0.3931 kPa -1 and a high pressure range sensitivity of 2.1111 kPa -1 .

[0066] Example 5:

[0067] The present embodiment proposes a preparation method of a flexible pressure sensor with adjustable sensitivity in a suspended gate transistor type, comprising the following steps:

[0068] (1) Attach a polyimide mask to the glass substrate, then drop 0.5wt% silver nanowire dispersion liquid, heat continuously at 50°C, repeat drop three times, solidify at 70°C for 20min, tear off the polyimide mask, and form the source-drain electrode and the transistor conductive channel.

[0069] (2) Mix the main agent dimethylsiloxane and the auxiliary crosslinking agent at a mass ratio of 10:1, stir uniformly, spin coating the bubble-free polydimethylsiloxane on the prepared source-drain electrode at 500 rpm, heat and solidify at 90°C for 1h, tear off the solidified PDMS / AgNWs, and obtain the flexible and stretchable source-drain electrode.

[0070] (3) Take a small amount of 10mg / ml P3HT toluene solution drop on the calm water surface, after the solvent volatilization, P3HT self-assembly film floating on the water surface, transfer to the flexible electrode, natural drying can be used.

[0071] (4) Attach 0.4cm x 0.3cm size polyimide (main agent dimethylsiloxane and auxiliary crosslinking agent mass ratio of 10:1) gasket on both sides of the source-drain channel, the distance between the two gaskets is 0.3cm.

[0072] (5) Mix copolymer P(VDF-HFP), ionic liquid [EMIM][TFSI] and acetone with a mass ratio of 1:4:7, heat and stir at 70℃ for 2h to make the ionic liquid uniformly dispersed in the interstice of the copolymer, after the bubbles completely disappear, spin coating on the glass substrate at 500rpm, heat and solidify at 70℃ for 24h, cut into 1cm x 0.3cm and transfer to the gasket, the ionic gel is suspended above the conductive channel and cannot contact the active layer and the electrode.

[0073] (6) Mix the main agent dimethylsiloxane and the auxiliary crosslinking agent with a mass ratio of 20:1, spin coating on the glass substrate with a spin coater at 500rpm, heat and solidify at 90℃ for 1h, cut into 0.8cm x 0.3cm and transfer to the ionic gel, completely covering the ionic gel above the channel.

[0074] (7) Fix the device on the probe station, apply a voltage of-1.5V on the source-drain electrode, and apply different mechanical external force.

[0075] The pressure sensor prepared according to the above steps has a low pressure range sensitivity of 0.5189kPa -1 and a high pressure range sensitivity of 3.3132kPa -1 .

[0076] Example 6:

[0077] The present embodiment proposes a preparation method of a flexible pressure sensor with adjustable sensitivity in the form of a suspended gate transistor, comprising the following steps:

[0078] (1) Attach a polyimide mask to the glass substrate, then drop 0.5wt% silver nanowire dispersion liquid, heat continuously at 50℃, repeat drop three times, solidify at 70℃ for 20min, tear off the polyimide mask, form the source-drain electrode and transistor conductive channel.

[0079] (2) The main agent dimethylsiloxane and the auxiliary agent crosslinking agent are mixed and stirred uniformly at a mass ratio of 10:1. Bubble-free polydimethylsiloxane is spin-coated on the prepared source-drain electrode at 500 rpm, and heated and cured at 90°C for 1 h. The cured PDMS / AgNWs are torn off, and a flexible and stretchable source-drain electrode is obtained.

[0080] (3) A small amount of 10 mg / ml P3HT toluene solution is dropped on the calm water surface. After the solvent volatilizes, the P3HT self-assembled film floats on the water surface and is transferred to the flexible electrode. After natural air drying, it can be used.

[0081] (4) Polyimide (the mass ratio of the main agent dimethylsiloxane to the auxiliary agent crosslinking agent is 10:1) gaskets with a size of 0.4 cm×0.3 cm are attached on both sides of the source-drain channel, and the distance between the two gaskets is 0.3 cm.

[0082] (5) The copolymer P(VDF-HFP), the ionic liquid [EMIM][TFSI], and the acetone are mixed at a mass ratio of 1:4:7, heated and stirred at 70°C for 2 h to uniformly disperse the ionic liquid into the interstices of the copolymer. After the bubbles completely disappear, the mixture is spin-coated on a glass substrate at 500 rpm, heated and cured at 70°C for 24 h, cut into 1 cm×0.3 cm, and transferred to the gasket. The ionic gel is suspended above the conductive channel and cannot contact the active layer and the electrode.

[0083] (6) The main agent dimethylsiloxane and the auxiliary agent crosslinking agent are mixed and stirred uniformly at a mass ratio of 20:1. The mixture is spin-coated on a glass substrate at 500 rpm using a spin coater, heated and cured at 90°C for 1 h, cut into a size of 0.8 cm×0.3 cm, and then transferred to the ionic gel. The ionic gel above the channel is completely covered.

[0084] (7) The device is fixed on a probe station. A voltage of -0.5 V is applied to the source-drain electrode, and a bias voltage of -0.5 V is applied. Then different mechanical external forces are applied.

[0085] The pressure sensor prepared according to the above steps has a low-pressure range sensitivity of 0.4122 kPa -1 and a high-pressure range sensitivity of 1.9814 kPa -1 .

[0086] Example 7

[0087] The present embodiment provides a preparation method of a flexible pressure sensor with adjustable sensitivity in a suspended gate transistor mode, which comprises the following steps:

[0088] (1) Polyimide mask is pasted on the glass substrate, then 0.5wt% silver nanowire dispersion is drop-coated, heated at 50℃, repeated drop-coating three times, cured at 70℃ for 20min, and then the polyimide mask is removed to form the source-drain electrode and the transistor conductive channel.

[0089] (2) The main agent dimethylsiloxane and the auxiliary crosslinking agent are mixed and stirred uniformly at a mass ratio of 10:1, and the bubble-free polydimethylsiloxane is spin-coated on the prepared source-drain electrode at 500rpm, heated and cured at 90℃ for 1h, and then the cured PDMS / AgNWs are peeled off to obtain the flexible and stretchable source-drain electrode.

[0090] (3) A small amount of 10mg / ml P3HT toluene solution is dropped on the calm water surface, and after the solvent volatilizes, the P3HT self-assembled film floats on the water surface, and is transferred to the flexible electrode and naturally dried for use.

[0091] (4) Polyimide (main agent dimethylsiloxane and auxiliary crosslinking agent at a ratio of 10:1) gaskets with a size of 0.4cm×0.3cm are attached on both sides of the source-drain channel, and the distance between the two gaskets is 0.3cm.

[0092] (5) The copolymer P(VDF-HFP), the ionic liquid [EMIM][TFSI] and the acetone are mixed at a mass ratio of 1:4:7, heated and stirred at 70℃ for 2h to allow the ionic liquid to be uniformly dispersed into the interstices of the copolymer, and after the bubbles completely disappear, the glass substrate is spin-coated at 500rpm, heated and cured at 70℃ for 24h, and then cut into 1cm×0.3cm and transferred to the gasket. The ionic gel is suspended above the conductive channel and cannot contact the active layer and the electrode.

[0093] (6) The main agent dimethylsiloxane and the auxiliary crosslinking agent are mixed and stirred uniformly at a mass ratio of 20:1, and the glass substrate is spin-coated at 500rpm using a spin coater, heated and cured at 90℃ for 1h, and then cut into 1cm×0.3cm and transferred to the ionic gel to completely cover the ionic gel above the channel.

[0094] (7) The device is fixed on the probe station, a voltage of-0.5V is applied to the source-drain electrode, and a bias voltage of-1.0V is applied, and then different mechanical external forces are applied.

[0095] The pressure sensor prepared according to the above steps has a low pressure range sensitivity of 0.9066kPa -1 and a high pressure range sensitivity of 2.4922kPa -1 .

Claims

1. A flexible pressure sensor with adjustable sensitivity, characterized in that: include: Flexible electrode substrate, semiconductor layer, and pressure-sensitive layer as gate; The flexible electrode substrate includes an active drain electrode and a conductive channel; The semiconductor layer includes an active layer and a pad. The active layer completely covers the source / drain electrodes and the conductive channel and is in physical contact with the source / drain electrodes. The pad is disposed on the active layer and is correspondingly disposed on both sides of the conductive channel. The pressure-sensitive layer is located on the pad, forming a floating gate structure. When the flexible pressure sensor is subjected to external pressure, the pressure-sensitive layer deforms, changing the carrier mobility of the active layer, thus enabling sensitive detection of external pressure. The sensitivity of the flexible pressure sensor can be adjusted by regulating the source-drain voltage and the gate voltage. The active layer is a poly(3-hexylthiophene) film obtained by self-assembly; The pressure-sensitive layer is an ion gel layer; It also includes an encapsulation layer that covers the pressure-sensitive layer.

2. The flexible pressure sensor with adjustable sensitivity of the floating gate transistor type according to claim 1, characterized in that: The flexible electrode substrate further includes a flexible base, wherein the source and drain electrodes are embedded in the flexible base to form the flexible electrode substrate.

3. The flexible pressure sensor with adjustable sensitivity of the floating gate transistor type according to claim 1, characterized in that: The gasket is made of polydimethylsiloxane material.

4. A method for fabricating a flexible pressure sensor with adjustable sensitivity based on a suspended gate transistor, characterized in that: Includes the following steps: Step 1: Place a polyimide mask onto a glass substrate, then drop-coat a silver nanowire dispersion. After curing, peel off the polyimide mask to form source / drain electrodes and transistor conductive channels. Step 2: Mix the main agent dimethylsiloxane and crosslinking agent, spin-coat the source and drain electrodes and heat to cure, forming a flexible electrode substrate; Step 3: Dissolve poly(3-hexylthiophene) in toluene and drop it onto the water surface to form a nanofilm. Transfer the formed nanofilm onto the source and drain electrodes to completely cover the conductive channel and form an active layer. Step 4: Prepare polydimethylsiloxane pads, cut them into small pieces, and place them on the active layer, with the pads corresponding to both sides of the conductive channel; Step 5: Mix polymer P (VDF-HFP), ionic liquid [EMIM][TFSI] and acetone, spin coat the mixture onto the gasket, and heat to cure to form a pressure-sensitive layer; Step 6: Mix the main agent dimethylsiloxane and crosslinking agent, spin-coat it into an encapsulation layer, place it on top of the pressure-sensitive layer, and cover it on the ionogel.

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