Pressure-temperature-infrared multi-mode flexible sensor and preparation method and application thereof

Abstract

The invention discloses a pressure-temperature-infrared multi-mode flexible sensor and a preparation method and application thereof. The pressure-temperature-infrared multi-mode flexible sensor comprises a flexible substrate layer, a first electrode layer, a sensitive layer, a second electrode layer and a flexible protection layer which are sequentially arranged in a stacked mode in the arrangement direction. Wherein the sensitive layer comprises polyimide-MXene-bismuth telluride composite aerogel, the polyimide-MXene-bismuth telluride composite aerogel comprises polyimide, MXene and bismuth telluride, and the polyimide-MXene-bismuth telluride composite aerogel is internally provided with a three-dimensional porous structure. The pressure-temperature-infrared multi-mode flexible sensor provided by the invention can avoid complex layout of the sensor and complex signal transmission, has a mutual interference-free response capability, has a contact type sensing function and a non-contact type sensing function, and has the advantages of signal interference-free decoupling, avoidance of wear failure of a sensing device, high adaptability, no destructiveness, safety and the like.

Description

Technical Field

[0001] This invention belongs to the field of sensors, specifically relating to a pressure-temperature-infrared multimodal flexible sensor, its fabrication method, and its application. Background Technology

[0002] The first step in how humans recognize and perceive external information is that the human body simultaneously perceives and independently distinguishes multiple parameters such as pressure, temperature, and proximity through organs like the skin and eyes, and then performs corresponding actions after information processing. In the field of humanoid robots and other intelligent equipment, acquiring external information is the first step in the robot's interaction with the outside world. Therefore, imitating human sensory abilities has always been a persistent pursuit, and sensors are essentially extensions of human senses, serving as the main means and pathways for robots to acquire information from the natural world. Based on the ability of biomimetic humans to perceive the external environment, the sensors used in intelligent equipment can be broadly divided into two categories: non-contact and contact sensing. Non-contact sensors are mainly visual sensors, capable of sensing information such as distance, color, shape, and size; contact sensors are mainly tactile sensors, which sense the most information, including but not limited to mechanical stimuli, temperature, humidity, pain, texture, and material properties. However, both visual and tactile sensors have their own advantages and disadvantages in application. Therefore, if the two can be combined, using the intuitiveness of vision to locate and distinguish, and combining the sensation of touch to achieve precise recognition of objects, including parameters such as texture and material, the perception capabilities of humanoid robots and other intelligent equipment can be effectively improved.

[0003] Currently, the development of vision-touch fusion sensors mainly focuses on the simple integration of multiple sensors on a single platform, which falls under hardware integration. Although this method can effectively separate different stimuli, the integration process for multiple independent sensors is complex and consumes a lot of power, resulting in high costs. In addition, processing data from different types of sensors with different sampling rates, resolutions, and noise characteristics is challenging, and the process of converting sensor signals into electrical signals inevitably involves simultaneous sensing of voltage, pressure, and temperature, causing signal crosstalk and affecting the accuracy of the output results.

[0004] In addition, for the development of visual-touch sensors, the ability to achieve independent responses to multiple stimuli through a single sensor is a new strategy. This involves decoupling multiple input stimuli by utilizing different sensing mechanisms or electrical signal types. This innovative approach not only promises to provide more accurate measurements but also addresses the key limitations inherent in relying on a single electrical signal. Furthermore, the diversification of sensing mechanisms enables greater versatility and sensitivity, thereby improving its overall performance and practicality.

[0005] However, the existing technology still has the following drawbacks: (1) Limited measurement types: The measurement types of flexible sensors are limited. Specifically, they usually only sense one or two types of stimulus signals. This limited sensing type increases the volume of multimodal integrated devices and the number of signal output lines, increasing system complexity. (2) Coupling interference: Pressure and temperature measurements in flexible multimodal sensors are usually achieved by sharing a part of the material or circuit. This may cause cross-interference between pressure and temperature output signals due to the same response mechanism. That is, pressure measurement is affected by temperature changes, or temperature measurement is affected by pressure changes. This cross-interference may lead to inaccuracy of measurement results and difficulty in decoupling output results. (3) Complex manufacturing and integration: The manufacturing and integration of flexible multimodal sensors are relatively complex. They usually require the use of different types of materials and components, and fine processing and assembly. This makes the manufacturing and integration of sensors more expensive, requiring specialized manufacturing processes and technologies to realize device construction. (4) Stability and reliability: Flexible multimodal sensors may face challenges in terms of stability and reliability. Flexible materials and components may be affected by environmental conditions, mechanical stress and service life, which may lead to performance degradation or failure. The assessment and improvement of stability and reliability are important factors to consider when manufacturing and applying these types of sensors.

[0006] Therefore, how to construct an integrated flexible multimodal sensor to decouple multiple stimuli, thereby reducing system complexity and achieving the requirements of lightweight and practicality, is an urgent problem to be solved. Summary of the Invention

[0007] The main objective of this invention is to provide a pressure-temperature-infrared multimodal flexible sensor, its fabrication method, and its application, in order to overcome the shortcomings of the prior art.

[0008] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: The first aspect of the present invention provides a pressure-temperature-infrared multimodal flexible sensor, comprising a flexible substrate layer, a first electrode layer, a sensitive layer, a second electrode layer, and a flexible protective layer sequentially stacked along a setting direction; wherein the sensitive layer comprises a polyimide-MXene-bismuth telluride composite aerogel, the polyimide-MXene-bismuth telluride composite aerogel comprising polyimide, MXene, and bismuth telluride, and the polyimide-MXene-bismuth telluride composite aerogel having a three-dimensional porous structure inside.

[0009] A second aspect of the present invention provides a method for fabricating the pressure-temperature-infrared multimodal flexible sensor, comprising: A flexible substrate is provided as a flexible substrate layer, and a first electrode layer is deposited on the surface of the flexible substrate layer; Polyimide-MXene-bismuth telluride composite aerogel is coated on the surface of the first electrode layer to form a sensitive layer with a three-dimensional porous structure. A second electrode layer is deposited on the surface of the sensitive layer; A flexible protective layer is covered on the surface of the second electrode layer to obtain a pressure-temperature-infrared multimodal flexible sensor.

[0010] A third aspect of the present invention provides the application of the pressure-temperature-infrared multimodal flexible sensor in the field of flexible sensing.

[0011] A fourth aspect of the present invention provides a pressure-temperature-infrared multimodal sensing system comprising the pressure-temperature-infrared multimodal flexible sensor.

[0012] Compared with the prior art, the technical solution of the present invention has at least the following advantages: The polyimide-MXene-bismuth telluride composite aerogel provided by this invention utilizes the different sensing properties of the same sensitive material and achieves decoupling of multiple stimuli through independent sensing mechanisms such as thermo-voltage effect, piezoresistive effect, and photoelectric effect. It has independent sensing mechanisms for pressure, temperature, and infrared, and also has stable sensing performance.

[0013] Furthermore, the pressure-temperature-infrared multimodal flexible sensor provided by this invention adopts a polyimide-MXene-bismuth telluride composite aerogel that integrates pressure, temperature, and infrared sensing, avoiding complex sensor layout and signal transmission. The material is also inexpensive, avoiding the disadvantages of high-cost material synthesis, and the manufacturing process is simple and easy, making it suitable for widespread production. Moreover, due to its independent sensing mechanism, it achieves a response capability without mutual interference, and combines contact and non-contact sensing functions. This gives the pressure-temperature-infrared multimodal flexible sensor of this invention advantages such as interference-free signal decoupling, avoidance of sensor wear and failure, strong adaptability, non-destructive nature, and safety. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a structural diagram of a pressure-temperature-infrared multimodal flexible sensor in a typical embodiment of the present invention; Figure 2This is a schematic diagram of the preparation process of polyimide-MXene-bismuth telluride composite aerogel in a typical embodiment of the present invention. Figure 3 This is a SEM image of the polyimide-MXene-bismuth telluride composite aerogel prepared in Example 1 of the present invention at 20 μm. Figure 4 This is a SEM image of the polyimide-MXene-bismuth telluride composite aerogel prepared in Example 1 of the present invention at 500 μm. Figure 5 This is a pressure response performance diagram of the pressure-temperature-infrared multimodal flexible sensor of the present invention; Figure 6 This is a graph showing the pressure sensing response time and recovery time of the pressure-temperature-infrared multimodal flexible sensor of the present invention. Figure 7 This is a diagram showing the pressure response cyclic stability of the pressure-temperature-infrared multimodal flexible sensor of the present invention. Figure 8 This is a pressure response sensitivity performance diagram of the pressure-temperature-infrared multimodal flexible sensor of the present invention; Figure 9 This is a graph showing the thermoelectric temperature response sensitivity performance of the pressure-temperature-infrared multimodal flexible sensor of the present invention. Figure 10 This is a graph showing the temperature sensing response time and recovery time of the pressure-temperature-infrared multimodal flexible sensor of the present invention. Figure 11 This is a diagram showing the temperature response cyclic stability of the pressure-temperature-infrared multimodal flexible sensor of the present invention. Figure 12 This is a graph showing the pressure-temperature response performance of the pressure-temperature-infrared multimodal flexible sensor of the present invention without interference. Figure 13 This is a graph showing the temperature-pressure response performance of the pressure-temperature-infrared multimodal flexible sensor of the present invention without interference. Figure 14 The graphs show the performance of the pressure-temperature-infrared multimodal flexible sensor of the present invention at different wavelengths of light. Figure 15 The image shows the optical sensing performance of the pressure-temperature-infrared multimodal flexible sensor of this invention in the 365 nm band. Figure 16 This is a graph showing the optical response time performance of the pressure-temperature-infrared multimodal flexible sensor of the present invention in the 365 nm band; Figure 17 This is a graph showing the performance of the light response of the pressure-temperature-infrared multimodal flexible sensor of the present invention in the 365 nm band as a function of distance. Figure 18This is a graph showing the performance of the pressure-temperature-infrared multimodal flexible sensor of the present invention in detecting the shape, hardness, and material of an object. Detailed Implementation

[0016] The invention will be more fully understood by reading the following detailed description. However, it should be understood that the detailed description disclosed below is merely exemplary of the invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as a representative basis for teaching those skilled in the art to employ the invention in different ways in any suitable detailed embodiment.

[0017] The first aspect of the present invention provides a pressure-temperature-infrared multimodal flexible sensor, comprising a flexible substrate layer 5, a first electrode layer 4, a sensitive layer 3, a second electrode layer 2, and a flexible protective layer 1 sequentially stacked along a setting direction; wherein, the sensitive layer 3 comprises a polyimide-MXene-bismuth telluride composite aerogel, the polyimide-MXene-bismuth telluride composite aerogel comprising polyimide, MXene, and bismuth telluride, and the polyimide-MXene-bismuth telluride composite aerogel has a three-dimensional porous structure inside.

[0018] In some embodiments, the polyimide-MXene-bismuth telluride composite aerogel is a nanosensitive material that integrates pressure sensing, temperature sensing, and infrared sensing.

[0019] In some implementations, the pore size of the three-dimensional porous structure is 20~50nm.

[0020] In some embodiments, the polyimide has a mass fraction of 10-20 wt%, the MXene has a mass fraction of 10-20 wt%, and the bismuth telluride has a mass fraction of 60-80 wt%.

[0021] In some embodiments, the flexible protective layer 1 is disposed on the top surface of the second electrode layer, and the flexible substrate is disposed on the bottom surface of the first electrode layer.

[0022] In some implementations, the first electrode layer 4 and the second electrode layer 2 are electrically connected to an external detection circuit, at least for collecting pressure, temperature and infrared signals from the sensitive layer 3.

[0023] In some embodiments, the thickness of the flexible substrate layer 5 is 20~300 μm.

[0024] In some embodiments, the flexible substrate layer 5 is made of at least one of polyimide, polydimethylsiloxane, polyethylene terephthalate, polyethylene, etc., but is not limited to this.

[0025] In some implementations, the thickness of the sensitive layer 3 is 500~3000 μm.

[0026] In some implementations, the thickness of the flexible protective layer 1 is 5~100 μm.

[0027] In some embodiments, the flexible protective layer 1 is made of a material with good biocompatibility, and the material of the flexible protective layer 1 includes at least one of polyvinyl alcohol, polydimethylsiloxane, etc., but is not limited to this.

[0028] In some embodiments, the thickness of the first electrode layer 4 is 10~20 μm.

[0029] In some embodiments, the thickness of the second electrode layer 2 is 10~20 μm.

[0030] In some embodiments, the first electrode layer 4 and the second electrode layer 2 are both metal conductive electrode sheets, and the materials of the first electrode layer 4 and the second electrode layer 2 include at least one of gold, silver, copper, etc., but are not limited to this.

[0031] In some embodiments, both the flexible substrate layer 5 and the flexible protective layer 1 are flexible and attachable.

[0032] An exemplary embodiment of the pressure-temperature-infrared multimodal flexible sensor of the present invention is shown in the figure below. Figure 1 As shown, the sensor comprises a flexible substrate layer 5, a first electrode layer 4, a sensitive layer 3, a second electrode layer 2, and a flexible protective layer 1, which are stacked sequentially from bottom to top.

[0033] Specifically, the pressure-temperature-infrared multimodal flexible sensor provided by this invention integrates pressure, temperature, and infrared sensing through a polyimide-MXene-bismuth telluride composite aerogel. The specific process is as follows: The porous structure of polyimide-MXene changes its internal conductive network under pressure, and can respond to pressure through changes in resistance. MXene and bismuth telluride are both thermoelectric materials. When the device comes into contact with an object with a temperature difference from room temperature, it can generate a thermoelectric voltage value through the temperature difference between the contact surface and the room temperature of the other surface, thus responding to temperature changes. Bismuth telluride is a photoelectric material that can have the maximum photocurrent output for ultraviolet light. It can respond to ultraviolet light intensity through the photocurrent value, thus realizing the integration of pressure, temperature and infrared sensing.

[0034] A second aspect of the present invention provides a method for fabricating the pressure-temperature-infrared multimodal flexible sensor, comprising: A flexible substrate is provided as a flexible substrate layer 5, and a first electrode layer 4 is deposited on the surface of the flexible substrate layer 5; Polyimide-MXene-bismuth telluride composite aerogel is coated on the surface of the first electrode layer 4 to form a sensitive layer 3 with a three-dimensional porous structure; A second electrode layer 2 is deposited on the surface of the sensitive layer 3; A flexible protective layer 1 is covered on the surface of the second electrode layer 2 to obtain a pressure-temperature-infrared multimodal flexible sensor.

[0035] In some embodiments, the preparation method of the polyimide-MXene-bismuth telluride composite aerogel includes: Tellurite, bismuth salt, surfactant and organic solvent are mixed evenly to obtain a first precursor solution. The first precursor solution is then evenly dispersed with MXene, and a isothermal reaction is carried out to complete the growth of bismuth telluride crystals, thus obtaining the MXene-bismuth telluride composite. A second precursor solution containing polyamic acid, MXene-bismuth telluride complex and solvent was frozen in liquid nitrogen and then freeze-dried under vacuum to obtain a precursor aerogel. The precursor aerogel was annealed under an inert atmosphere to obtain a polyimide-MXene-bismuth telluride composite aerogel.

[0036] In some embodiments, the preparation method of the polyimide-MXene-bismuth telluride composite aerogel specifically includes: mixing tellurite, bismuth salt, surfactant and organic solvent uniformly to obtain the first precursor solution, adjusting the pH value of the first precursor solution to neutral, adding MXene and dispersing it uniformly, and then performing the isothermal reaction to complete the growth of bismuth telluride crystals and obtain the MXene-bismuth telluride composite.

[0037] Furthermore, the isothermal reaction is carried out at a temperature of 140~200℃ for a time of 4~8 h.

[0038] Furthermore, the liquid-to-solid ratio of the first precursor solution to MXene is 100 ~ 1000: 1 mL / g.

[0039] Further, the mass ratio of the tellurite, bismuth salt, surfactant, and organic solvent is 1:(1~1.6):(0.5~0.8):(50~200).

[0040] Furthermore, the tellurite includes, but is not limited to, sodium tellurite.

[0041] Furthermore, the bismuth salt includes, but is not limited to, bismuth nitrate pentahydrate.

[0042] Furthermore, the surfactant includes, but is not limited to, polyvinylpyrrolidone.

[0043] Furthermore, the organic solvent includes, but is not limited to, ethylene glycol.

[0044] In this invention, after the bismuth telluride crystal growth is completed, the MXene-bismuth telluride composite is obtained by centrifugation, washing, and vacuum drying.

[0045] Furthermore, the centrifugal washing is performed at a speed of 10,000 r / min for a time of 20 min.

[0046] Furthermore, the vacuum drying process involves a vacuum degree of 0-20 Pa, a temperature of 40-80 °C, and a time of 12-48 h, preferably a temperature of 60 °C and a time of 24 h.

[0047] In some embodiments, the preparation method of the polyimide-MXene-bismuth telluride composite aerogel specifically includes: mixing the polyamic acid and the solvent with water to obtain a polyamic acid solution; The MXene-bismuth telluride complex was subjected to ultrasonic treatment with water to obtain an MXene-bismuth telluride complex dispersion; The polyamic acid solution and the MXene-bismuth telluride complex dispersion are mixed evenly to obtain the second precursor solution.

[0048] Further, the mass ratio of the polyamic acid, solvent and MXene-bismuth telluride composite is (0.2~0.6):(0.01~0.3):(0.01~0.1):(1~6).

[0049] Furthermore, the solvent includes triethylamine.

[0050] In some embodiments, the preparation method of the polyimide-MXene-bismuth telluride composite aerogel specifically includes: freezing the second precursor solution with liquid nitrogen for 0.1~0.5 h to fix the three-dimensional network structure, and then freeze-drying it under vacuum at -50~-25℃ and 0~20 Pa for 12~48 h to obtain the precursor aerogel.

[0051] In some implementations, the annealing process specifically includes: The temperature is increased from room temperature to a first temperature at a first heating rate, and then the temperature is maintained for the first time. The temperature is increased from the first temperature to the second temperature at a second heating rate, and then a second heat preservation is performed. The temperature is increased from the second temperature to the third temperature at a third heating rate, and then a third heat preservation is performed. The temperature is increased from the third temperature to the fourth temperature at a fourth heating rate, and then a fourth heat preservation is performed. The temperature is increased from the fourth temperature to the fifth temperature at a fifth heating rate, and then a fifth heat preservation is performed.

[0052] Furthermore, the first heating rate is 0.5~5℃ / min, the first temperature is 60~90℃, and the first holding time is 5~30 min; Furthermore, the second heating rate is 0.5~3℃ / min, the second temperature is 100~140℃, and the second holding time is 5~30 min; Furthermore, the third heating rate is 0.5~5 ℃ / min, the third temperature is 140~180℃, and the third holding time is 5~30 min; Furthermore, the fourth heating rate is 0.5~3 ℃ / min, the fourth temperature is 180~220℃, and the fourth holding time is 30~120 min; Furthermore, the fifth heating rate is 0.5~3 ℃ / min, the fifth temperature is 230~300℃, and the fifth holding time is 30~120 min.

[0053] In a typical embodiment of the present invention, the preparation method of the polyimide-MXene-bismuth telluride composite aerogel (PI-MXene@Bi2Te3 composite aerogel) specifically includes the following steps: S1. Sodium tellurite (Na2TeO3), bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and polyvinylpyrrolidone (PVP) were dissolved in ethylene glycol and magnetically stirred for 30 min to form a homogeneous precursor solution. Sodium hydroxide (NaOH) was then added to adjust the pH to neutral, and stirring continued for 30 min until the solution became transparent. MXene was added to the transparent solution and ultrasonically dispersed for 2 h to achieve stable suspension of MXene. The mixed solution was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 140–200 °C for 4–8 h to complete crystal growth. After the reaction, the mixture was washed sequentially with deionized water and anhydrous ethanol by centrifugation (10000 r / min, 20 min) to remove unreacted ions and organic residues. Finally, it was vacuum dried at 0–20 Pa and 40–80 °C for 12–48 h to obtain a gray-black MXene@Bi2Te3 composite powder.

[0054] S2. Dissolve polyamic acid (PAA) and triethylamine (TEA) in deionized water to form a PAA solution.

[0055] S3. Add MXene@Bi2Te3 powder to deionized water and sonicate at 75 W for 90 min to obtain MXene@Bi2Te3 dispersion.

[0056] S4. After mixing the PAA solution with the MXene@Bi2Te3 dispersion, continue magnetic stirring for 24 h to obtain the precursor dispersion.

[0057] S5. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after being frozen in liquid nitrogen for 0.1 to 0.5 h to fix the three-dimensional network structure, it is freeze-dried for 24 to 48 h (-50 to -25 ℃, 0 to 20 Pa) to obtain the precursor aerogel.

[0058] S6. Anneal the precursor aerogel from step S5 under an argon atmosphere. The steps include: heating from room temperature to 60-90℃ at a rate of 0.5-5℃ / min and holding for 5-30 min; heating from 60-90℃ to 100-140℃ at a rate of 0.5-3℃ / min and holding for 5-30 min; heating from 100-140℃ to 140-180℃ at a rate of 0.5-5℃ / min and holding for 5-30 min; heating from 140-180℃ to 180-220℃ at a rate of 0.5-3℃ / min and holding for 30-120 min; heating from 180-220℃ to 230-300℃ at a rate of 0.5-3℃ / min and holding for 30-120 min; and cooling to room temperature in the furnace after the holding period to obtain the PI-MXene@Bi2Te3 composite aerogel material.

[0059] Specifically, the reaction mechanism involved in the preparation method of the polyimide-MXene-bismuth telluride composite aerogel of the present invention is as follows: In step S1, bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) reacts with sodium hydroxide (NaOH) to form Bi(OH)3, and then Bi(OH)3 reacts with sodium tellurite (Na2TeO3) to form Bi2Te3. In step S6, PAA undergoes a cross-linking reaction to generate polyimide PI during a gradual temperature increase.

[0060] An exemplary schematic diagram of the preparation route of PI-MXene@Bi2Te3 composite aerogel in a typical embodiment of the present invention is shown below. Figure 2 As shown.

[0061] A third aspect of the present invention provides the application of the pressure-temperature-infrared multimodal flexible sensor in the field of flexible sensing.

[0062] A fourth aspect of the present invention provides a pressure-temperature-infrared multimodal sensing system comprising the pressure-temperature-infrared multimodal flexible sensor.

[0063] Furthermore, the pressure-temperature-infrared multimodal sensing system has the function of sensing and responding to pressure, temperature, and infrared signals without interference in contact or non-contact modes.

[0064] In summary, this invention innovatively utilizes the different sensing properties of the same sensitive material based on aerogel composite sensitive materials with three independent response mechanisms to construct an integrated flexible multimodal sensor. Specifically, it uses independent sensing mechanisms such as thermo-voltage effect, piezoresistive effect, and photoelectric effect to decouple multiple stimuli, thereby reducing system complexity and achieving the requirements of lightweight and practicality. Moreover, the resulting flexible multimodal sensor has the ability to respond without mutual interference and has both contact and non-contact sensing functions.

[0065] The present invention is further illustrated below by way of examples, but the invention is not limited to the scope of the examples described. All reagents and raw materials used in the following examples are commercially available, and test methods not specifically specified are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0066] Example 1 A method for preparing a polyimide-MXene-bismuth telluride composite aerogel specifically includes the following steps: S1. 332 mg sodium tellurite (Na2TeO3), 485 mg bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and 200 mg polyvinylpyrrolidone (PVP) were dissolved in 40 mL of ethylene glycol and stirred magnetically for 30 min to form a homogeneous precursor solution. Then, 400 mg sodium hydroxide (NaOH) was added to adjust the pH of the system, and stirring was continued for 30 min until the solution became transparent. 100 mg MXene was added to the above solution, and stable suspension of MXene was achieved by ultrasonic dispersion for 2 h. The mixed solution was transferred to a 100 mL polytetrafluoroethylene-lined reactor and reacted at 180 ℃ for 6 h to complete crystal growth. After the reaction, the crystals were washed sequentially with deionized water and anhydrous ethanol by centrifugation (10000 r / min, 20 min) to remove unreacted ions and organic residues. Finally, the crystals were vacuum dried at 60 ℃ for 24 h to obtain a gray-black MXene@Bi2Te3 composite powder.

[0067] S2. Dissolve 0.54 g of polyamic acid (PAA) and 0.25 mL of triethylamine (TEA) in 10 mL of deionized water to form a PAA solution.

[0068] S3. Preparation of 5 mg / mL MXene@Bi2Te3 dispersion: Add 5 mg MXene@Bi2Te3 powder to 1 mL of deionized water and sonicate at 75 W for 90 min to obtain dispersion.

[0069] S4. Mix 4 mL of PAA solution with 2 mL of MXene@Bi2Te3 dispersion and continue magnetic stirring for 24 h to obtain the precursor dispersion.

[0070] S5. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after being frozen in liquid nitrogen for 0.2 h to fix the three-dimensional network structure, it is freeze-dried for 48 h (-50 ℃, 10 Pa) to obtain the precursor aerogel.

[0071] S6. Anneal the precursor aerogel from step S5 under an argon atmosphere. The steps include: heating from room temperature to 80°C at a rate of 2°C / min and holding for 20 min; heating from 80°C to 110°C at a rate of 1°C / min and holding for 20 min; heating from 110°C to 150°C at a rate of 2°C / min and holding for 20 min; heating from 150°C to 200°C at a rate of 2°C / min and holding for 60 min; heating from 200°C to 250°C at a rate of 1°C / min and holding for 90 min; and cooling to room temperature in the furnace after the holding period to obtain the PI-MXene@Bi2Te3 composite aerogel material.

[0072] The SEM image of the PI-MXene@Bi2Te3 composite aerogel material obtained in this embodiment is shown below. Figure 3 As shown. From Figure 1 It can be seen that the composite aerogel material has a three-dimensional porous structure with a pore size of approximately 20-50 μm. The mass fraction of the polyimide is approximately 15 wt%, the mass fraction of MXene is approximately 15 wt%, and the mass fraction of bismuth telluride is approximately 70 wt%.

[0073] A method for fabricating a pressure-temperature-infrared multimodal flexible sensor specifically includes the following steps: The PI-MXene@Bi2Te3 composite aerogel material prepared in step S6 is coated with silver paste on the flexible substrate layer 5 on which the first electrode layer 4 has been deposited, and then dried at 60°C for 0.5 h to form a sensitive layer 3 with a three-dimensional porous aerogel structure. Then, a second electrode layer 2 is deposited on the sensitive layer 3, and a material with good biocompatibility is coated on the surface of the second electrode layer 2 to form a flexible protective layer 1, so that the flexible protective layer 1, the second electrode layer 2, the sensitive layer 3, the first electrode layer 4 and the flexible substrate are integrated to obtain a pressure-temperature-infrared multimodal flexible sensor.

[0074] The sensitive layer 3 has a thickness of 2500 μm, the flexible substrate layer 5 has a thickness of 120 μm and is made of polydimethylsiloxane, the flexible protective layer 1 has a thickness of 90 μm and is made of polydimethylsiloxane, the first electrode layer 4 has a thickness of 15 μm and is made of Cu, and the second electrode layer 2 has a thickness of 15 μm and is made of Cu.

[0075] A pressure-temperature-infrared multimodal sensing system: A pressure-temperature-infrared multimodal flexible sensor is connected to a back-end processing circuit board and a high-precision source meter to construct a pressure-temperature-infrared multimodal sensing system.

[0076] Example 2 The method for preparing a polyimide-MXene-bismuth telluride composite aerogel provided in this embodiment differs from that in Example 1 only in that: S1. Dissolve 200 mg sodium tellurite (Na2TeO3), 200 mg bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and 100 mg polyvinylpyrrolidone (PVP) in 10 mL of ethylene glycol and stir magnetically for 30 min to form a homogeneous precursor solution.

[0077] In this embodiment, the PI-MXene@Bi2Te3 composite aerogel material contains approximately 10 wt% polyimide, approximately 20 wt% MXene, and approximately 70 wt% bismuth telluride.

[0078] Example 3 The method for preparing a polyimide-MXene-bismuth telluride composite aerogel provided in this embodiment differs from that in Example 1 only in that: S1. Dissolve 500 mg sodium tellurite (Na2TeO3), 800 mg bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and 400 mg polyvinylpyrrolidone (PVP) in 100 mL of ethylene glycol and stir magnetically for 30 min to form a homogeneous precursor solution.

[0079] In this embodiment, the PI-MXene@Bi2Te3 composite aerogel material has a polyimide mass fraction of approximately 10 wt%, an MXene mass fraction of approximately 10 wt%, and a bismuth telluride mass fraction of approximately 80 wt%.

[0080] Example 4 The method for preparing a polyimide-MXene-bismuth telluride composite aerogel provided in this embodiment differs from that in Example 1 only in that: S4. Mix 1 mL of PAA solution with 1 mL of MXene@Bi2Te3 dispersion and continue magnetic stirring for 24 h to obtain the precursor dispersion.

[0081] Example 5 The method for preparing a polyimide-MXene-bismuth telluride composite aerogel provided in this embodiment differs from that in Example 1 only in that: S4. Mix 6 mL of PAA solution with 4 mL of MXene@Bi2Te3 dispersion and continue magnetic stirring for 24 h to obtain the precursor dispersion.

[0082] Example 6 The method for preparing a polyimide-MXene-bismuth telluride composite aerogel provided in this embodiment differs from that in Example 1 only in that: S5. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after being frozen in liquid nitrogen for 0.5 h to fix the three-dimensional network structure, it is freeze-dried for 12 h (-50 ℃, 20 Pa) to obtain the precursor aerogel.

[0083] Example 7 The method for preparing a polyimide-MXene-bismuth telluride composite aerogel provided in this embodiment differs from that in Example 1 only in that: S5. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after being frozen in liquid nitrogen for 0.1 h to fix the three-dimensional network structure, it is freeze-dried for 48 h (-40 ℃, 10 Pa) to obtain the precursor aerogel.

[0084] Comparative Example 1 The method for preparing a composite aerogel provided in this comparative example differs from that in Example 1 in that: S1. 332 mg sodium tellurite (Na2TeO3), 485 mg bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and 200 mg polyvinylpyrrolidone (PVP) were dissolved in 40 mL of ethylene glycol and stirred magnetically for 30 min to form a homogeneous precursor solution. Then, 400 mg sodium hydroxide (NaOH) was added to adjust the pH of the system, and stirring was continued for 30 min until the solution became transparent. 100 mg MXene was added to the above solution, and stable suspension of MXene was achieved by ultrasonic dispersion for 2 h. The mixed solution was transferred to a 100 mL polytetrafluoroethylene-lined reactor and reacted at 180 ℃ for 6 h to complete crystal growth. After the reaction, the crystals were washed sequentially with deionized water and anhydrous ethanol by centrifugation (10000 r / min, 20 min) to remove unreacted ions and organic residues. Finally, the crystals were vacuum dried at 60 ℃ for 24 h to obtain a gray-black MXene@Bi2Te3 composite powder.

[0085] S2. Preparation of 5 mg / mL MXene@Bi2Te3 dispersion: Add 5 mg MXene@Bi2Te3 powder to 100 mL of deionized water and sonicate at 75 W for 90 min to obtain an aqueous dispersion.

[0086] S3. 2 mL of MXene@Bi2Te3 dispersion was injected into a polytetrafluoroethylene mold. After the three-dimensional network structure was fixed by liquid nitrogen freezing, the MXene@Bi2Te3 composite aerogel material was obtained by freeze drying for 48 h (-50 ℃, 10 Pa).

[0087] The performance of the obtained flexible sensor is as follows: it has pressure-temperature-infrared multimodal response performance, but due to the lack of PI as an aerogel framework structure, the mechanical stability is poor and the response stability of the fabricated device is poor.

[0088] Comparative Example 2 The method for preparing a composite aerogel provided in this comparative example differs from that in Example 1 in that: S1. 332 mg of sodium tellurite (Na2TeO3), 485 mg of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and 200 mg of polyvinylpyrrolidone (PVP) were dissolved in 40 mL of ethylene glycol and magnetically stirred for 30 min to form a homogeneous precursor solution. Then, 400 mg of sodium hydroxide (NaOH) was added to adjust the pH of the system, and stirring continued for 30 min until the solution became transparent. The solution was transferred to a 100 mL polytetrafluoroethylene-lined reactor and reacted at 180 ℃ for 6 h to complete crystal growth. After the reaction, the mixture was washed sequentially with deionized water and anhydrous ethanol by centrifugation (10000 r / min, 20 min) to remove unreacted ions and organic residues. Finally, it was vacuum dried at 60 ℃ for 24 h to obtain a gray-black Bi2Te3 composite powder.

[0089] S2. Dissolve 0.54 g of polyamic acid (PAA) and 0.25 mL of triethylamine (TEA) in 10 mL of deionized water to form a PAA solution.

[0090] S3. Preparation of 5 mg / mL Bi2Te3 dispersion: Add 5 mg Bi2Te3 powder to 100 mL of deionized water and sonicate at 75 W for 90 min to obtain an aqueous dispersion.

[0091] S4. Mix 4 mL of PAA solution with 2 mL of Bi2Te3 dispersion and continue magnetic stirring for 24 h to obtain precursor dispersion.

[0092] S5. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after the three-dimensional network structure is fixed by liquid nitrogen freezing, it is freeze-dried for 48 h (-50 ℃, 10 Pa) to obtain the precursor aerogel.

[0093] S6. Anneal the precursor aerogel from step S5 under an argon atmosphere. The steps include: heating from room temperature to 80°C at a rate of 2°C / min and holding for 20 min; heating from 80°C to 110°C at a rate of 1°C / min and holding for 20 min; heating from 110°C to 150°C at a rate of 2°C / min and holding for 20 min; heating from 150°C to 200°C at a rate of 2°C / min and holding for 60 min; heating from 200°C to 250°C at a rate of 1°C / min and holding for 90 min; and cooling to room temperature in the furnace after the holding period to obtain the PI@Bi2Te3 composite aerogel material.

[0094] The resulting flexible sensor exhibits thermoelectric response due to temperature difference and infrared response, but lacks pressure response.

[0095] Comparative Example 3 The method for preparing a composite aerogel provided in this comparative example differs from that in Example 1 only in that: S1. Dissolve 0.54 g of polyamic acid (PAA) and 0.25 mL of triethylamine (TEA) in 10 mL of deionized water to form a PAA solution.

[0096] S2. Preparation of 5 mg / mL MXene dispersion: Add 5 mg MXene powder to 100 mL of deionized water and sonicate at 75 W for 90 min to obtain an aqueous dispersion.

[0097] S3. Mix 4 mL of PAA solution with 2 mL of MXene dispersion and continue magnetic stirring for 24 h to obtain the precursor dispersion.

[0098] S4. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after being frozen and fixed in liquid nitrogen to form a three-dimensional network structure, it is freeze-dried for 48 h (-50 ℃, 10 Pa) to obtain the precursor aerogel.

[0099] S5. Anneal the precursor aerogel from step S5 under an argon atmosphere. The steps include: heating from room temperature to 80°C at a rate of 2°C / min and holding for 20 min; heating from 80°C to 110°C at a rate of 1°C / min and holding for 20 min; heating from 110°C to 150°C at a rate of 2°C / min and holding for 20 min; heating from 150°C to 200°C at a rate of 2°C / min and holding for 60 min; heating from 200°C to 250°C at a rate of 1°C / min and holding for 90 min; and cooling to room temperature in the furnace after the holding period to obtain the PI@MXene composite aerogel material.

[0100] The performance of the resulting flexible sensor is as follows: it has pressure response performance, poor temperature difference thermoelectric response performance, but no infrared response performance.

[0101] Comparative Example 4 The PI skeleton structure is obtained by one-step annealing: S1. 332 mg sodium tellurite (Na2TeO3), 485 mg bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and 200 mg polyvinylpyrrolidone (PVP) were dissolved in 40 mL of ethylene glycol and stirred magnetically for 30 min to form a homogeneous precursor solution. Then, 400 mg sodium hydroxide (NaOH) was added to adjust the pH of the system, and stirring was continued for 30 min until the solution became transparent. 100 mg MXene was added to the above solution, and stable suspension of MXene was achieved by ultrasonic dispersion for 2 h. The mixed solution was transferred to a 100 mL polytetrafluoroethylene-lined reactor and reacted at 180 ℃ for 6 h to complete crystal growth. After the reaction, the crystals were washed sequentially with deionized water and anhydrous ethanol by centrifugation (10000 r / min, 20 min) to remove unreacted ions and organic residues. Finally, the crystals were vacuum dried at 60 ℃ for 24 h to obtain a gray-black MXene@Bi2Te3 composite powder.

[0102] S2. Dissolve 0.54 g of polyamic acid (PAA) and 0.25 mL of triethylamine (TEA) in 10 mL of deionized water to form a PAA solution.

[0103] S3. Preparation of 5 mg / mL MXene@Bi2Te3 dispersion: Add 5 mg MXene@Bi2Te3 powder to 100 mL of deionized water and sonicate at 75 W for 90 min to obtain an aqueous dispersion.

[0104] S4. Mix 4 mL of PAA solution with 2 mL of MXene@Bi2Te3 dispersion and continue magnetic stirring for 24 h to obtain the precursor dispersion.

[0105] S5. The precursor dispersion from step S4 is injected into a polytetrafluoroethylene mold, and after being frozen and fixed in liquid nitrogen to form a three-dimensional network structure, it is freeze-dried for 72 h (-50 ℃, 10 Pa) to obtain the precursor aerogel.

[0106] S6. Anneal the precursor aerogel from step S5 under an argon atmosphere. The steps are as follows: heat the aerogel from room temperature to 250°C at a rate of 2°C / min and hold it at that temperature for 90 min. After holding, cool it to room temperature in the furnace to obtain the PI-MXene@Bi2Te3 composite aerogel material.

[0107] The performance of the obtained flexible sensor is as follows: it has pressure-temperature-infrared multimodal response performance, but due to the excessive rigidity of the one-step annealed PI as an aerogel skeleton structure, the mechanical stability is poor and the response stability of the fabricated device is poor.

[0108] Performance testing (1) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to pressure response performance testing. The specific testing method is as follows: The flexible sensor was fixed on the base of the force gauge, and a pressure load was applied to the device by vertically moving the force gauge. The magnitude of the applied pressure was recorded in real time using the force gauge, and the change signal of the device resistance value was collected using an electrochemical workstation. During the experiment, the electrochemical workstation synchronously applied a DC bias voltage of 0.5 V to the sensor. By establishing the resistance-time relationship, the response characteristics of the device resistance value as a function of pressure magnitude were derived.

[0109] The test results are as follows Figure 5 As shown, from Figure 5 It can be seen that the resistance value of the flexible sensor gradually decreases as the pressure increases.

[0110] (2) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to pressure sensing response and recovery tests. The specific test method is as follows: The flexible sensor was fixed on the base of the force gauge, and a pressure load was applied to the device by vertically moving the force gauge. The magnitude of the applied pressure was recorded in real time using the force gauge, and the change signal of the device resistance value was collected using an electrochemical workstation. During the experiment, the electrochemical workstation synchronously applied a DC bias voltage of 0.5 V to the sensor. By establishing the resistance-time relationship, the device response time was derived.

[0111] The test results are as follows Figure 6 As shown, from Figure 6 It can be seen that the flexible sensor has a response time of 1s and a recovery time of 0.6s under 2N pressure.

[0112] (3) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to a pressure response cycle stability test. The test method is as follows: The flexible sensor was fixed on the base of the force gauge, and a pressure load was applied to the device by vertically moving the force gauge. The magnitude of the applied pressure was recorded in real time using the force gauge, and the change signal of the device resistance value was collected using an electrochemical workstation. During the experiment, the electrochemical workstation synchronously applied a DC bias voltage of 0.5 V to the sensor. By establishing the resistance-time relationship, the response stability of the device under a fixed pressure change was derived.

[0113] The test results are as follows Figure 7 As shown, from Figure 7 It can be seen that the flexible sensor still has responsiveness after 1000 cycles of 2N pressure.

[0114] (4) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to pressure response sensitivity testing. The specific testing method is as follows: The flexible sensor was fixed on the base of the force gauge, and a pressure load was applied to the device by vertically moving the force gauge. The magnitude of the applied pressure was recorded in real time using the force gauge, and the change signal of the device resistance value was collected using an electrochemical workstation. During the experiment, the electrochemical workstation synchronously applied a DC bias voltage of 0.5V to the sensor. By establishing the resistance-pressure relationship, the device response sensitivity was derived.

[0115] The test results are as follows Figure 8 As shown, from Figure 8 It can be seen that the pressure response sensitivity of the flexible sensor is 0.698 kΩ / N.

[0116] (5) The thermoelectric temperature response sensitivity test was performed on the pressure-temperature-infrared multimodal flexible sensor obtained in Example 1. The test method is as follows: The flexible sensor was fixed on the base of the force gauge, and the ceramic heating element was attached to the probe of the step force gauge. The ceramic heating element could be moved vertically by running the force gauge to make it contact the surface of the device. At the same time, the temperature of the ceramic heating element could be controlled by applying different voltages (0 ~ 3 V) to the DC power supply connected to it. Thus, when it came into contact with the sensor surface, different temperature differences could be generated at the left and right or top and bottom ends of the device (temperature of the heating element contact surface and room temperature of the other side). The open-circuit voltage signal generated and output by the device due to the temperature difference could be collected by a multi-channel electrical tester to evaluate its sensing performance under different temperature differences.

[0117] The test results are as follows Figure 9 As shown, from Figure 9 The thermoelectric voltage output value of the flexible sensor under different temperature differences can be seen, and its Seebeck coefficient is calculated to be -4.92 µV / K.

[0118] (6) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to temperature sensing response and recovery tests. The test method is as follows: The flexible sensor was fixed on the base of the force gauge, and the ceramic heating element was attached to the probe of the step force gauge. The ceramic heating element could be moved vertically by running the force gauge to make it contact the surface of the device. At the same time, the temperature of the ceramic heating element could be controlled by applying different voltages (0 ~ 3 V) to the DC power supply connected to it. Thus, when it came into contact with the sensor surface, different temperature differences could be generated at the left and right or top and bottom ends of the device (temperature of the heating element contact surface and room temperature of the other side). The open-circuit voltage signal generated and output by the device due to the temperature difference could be collected by a multi-channel electrical tester to evaluate its sensing performance under different temperature differences.

[0119] The test results are as follows Figure 10 As shown, from Figure 10 It can be seen that the flexible sensor has a response time of 4.3s and a recovery time of 33.2s at a temperature difference of 20K.

[0120] (7) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to a temperature response cycle stability test. The test method is as follows: The flexible sensor was fixed on the base of the force gauge, and the ceramic heating element was attached to the probe of the step force gauge. The ceramic heating element could be moved vertically by running the force gauge to make it contact the surface of the device. At the same time, the temperature of the ceramic heating element could be controlled by applying different voltages (0 ~ 3 V) to the DC power supply connected to it. Thus, when it came into contact with the sensor surface, different temperature differences could be generated at the left and right or top and bottom ends of the device (temperature of the heating element contact surface and room temperature of the other side). The open-circuit voltage signal generated and output by the device due to the temperature difference could be collected by a multi-channel electrical tester to evaluate its sensing performance under different temperature differences.

[0121] The test results are as follows Figure 11 As shown, from Figure 11 It can be seen that the flexible sensor still has stable output response performance after being subjected to a temperature difference of 1000°C at 15K.

[0122] (8) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to pressure-temperature response interference test. The test method is as follows: The flexible sensor was placed at the bottom of the test bench, and the probe of the electric pressure gauge with the ceramic heating plate attached was moved vertically toward the surface of the device. Different pressures could be applied by the different moving distances of the pressure gauge. At the same time, the output temperature value on the ceramic heating plate could be adjusted by adjusting the voltage of the programmable DC power supply, thereby adjusting the temperature difference applied to the upper and lower ends of the device. At the same time, a DC voltage signal acquisition and recording instrument was used to collect and record data, and the real-time open-circuit voltage of the device under different temperature differences was measured, or the real-time resistance value of the device under different pressures was collected by a digital source meter.

[0123] The test results are as follows Figure 12 As shown, from Figure 12 It can be seen that under the same temperature difference, the thermoelectric output voltage of the device is not affected by pressure changes.

[0124] (10) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was subjected to temperature-pressure response interference test. The test method is as follows: The flexible sensor was placed at the bottom of the test bench, and the electric pressure gauge probe with the ceramic heating plate was moved vertically toward the surface of the device. Different pressures could be applied by the force gauge moving different distances. At the same time, the output temperature value on the ceramic heating plate could be adjusted by adjusting the voltage of the programmable DC power supply, thereby adjusting the temperature difference applied to the upper and lower ends of the device. At the same time, a DC voltage signal acquisition and recording instrument was used to collect and record data, and the real-time open-circuit voltage of the device under different temperature differences was measured, or the real-time resistance value of the device under different pressures was collected by a digital source meter.

[0125] The test results are as follows Figure 13 As shown, from Figure 13 It can be seen that under the same pressure, the temperature difference does not affect the change in the resistance value of the device.

[0126] (11) The optical sensing performance of the pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was tested at different wavelengths. The specific testing method is as follows: the device was fixed at the bottom of the test stage, the light source was fixed on the force gauge probe and 1 cm away from the surface of the device; different light sources were switched to perform different optical response performance tests, and the IV curve of the device was tested with a semiconductor parameter tester. The optical response limit distance could be tested by changing the distance between the light source and the device.

[0127] Test results of optical sensing performance at different wavelengths are as follows Figure 14 As shown, from Figure 14 It can be seen that the flexible sensor responds to different wavelengths, with the best response performance at 365 nm.

[0128] The test results of the 365 nm band optical sensing performance are as follows: Figure 15 As shown, from Figure 15 It can be seen that the flexible sensor has good response capability to 365 nm wavelength light of different intensities.

[0129] (12) The optical response time performance of the pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was tested in the 365 nm band. The specific test method is as follows: the device was fixed at the bottom of the test stage, the light source was fixed on the force gauge probe and 1 cm away from the surface of the device; different light sources were switched to perform different optical response performance tests, and the IV curve of the device was tested with a semiconductor parameter tester. The optical response limit distance could be tested by changing the distance between the light source and the device.

[0130] The test results are as follows Figure 16 As shown, from Figure 16 It can be seen that the flexible sensor has a response time of 120ms and a recovery time of 65ms to 365nm wavelength light.

[0131] (13) The light response performance of the pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was tested in the 365 nm band as a function of distance. The specific test method is as follows: The device was fixed at the bottom of the test stage, and the light source was fixed on the force gauge probe, 1 cm away from the surface of the device; different light sources were switched to perform different light response performance tests, and the IV curve of the device was tested using a semiconductor parameter tester. The light response limit distance could be tested by changing the distance between the light source and the device.

[0132] The test results are as follows Figure 17 As shown, from Figure 17 It can be seen that the flexible sensor still has good response capability to 365 nm wavelength light at a light intensity of 84 mW / cm2 at a distance of 20 cm.

[0133] (7) The pressure-temperature-infrared multimodal flexible sensor obtained in Example 1 was tested for its performance in detecting the shape, hardness and material of objects. The specific test method is as follows: The flexible sensor array was attached to the palm of the robotic hand. Objects with different shapes, hardness and material were placed on the surface of the array device. The shape of the object could be detected by applying light through the light-emitting area. The hardness of the object could be identified by applying a certain pressure. The material of the object could be determined by measuring the thermoelectric voltage generated by the temperature difference between the two ends of the object by heating it to a certain temperature.

[0134] The test results are as follows Figure 18 As shown, from Figure 18 It can be seen that the array device can recognize objects of different shapes.

Claims

1. A pressure-temperature-infrared multimodal flexible sensor, characterized in that, The pressure-temperature-infrared multi-mode flexible sensor comprises a flexible substrate layer (5), a first electrode layer (4), a sensitive layer (3), a second electrode layer (2) and a flexible protective layer (1) which are sequentially stacked in a setting direction; wherein the sensitive layer (3) comprises polyimide-MXene-bismuth telluride composite aerogel, the polyimide-MXene-bismuth telluride composite aerogel comprises polyimide, MXene and bismuth telluride, and the polyimide-MXene-bismuth telluride composite aerogel has a three-dimensional porous structure inside.

2. The pressure-temperature-infrared multi-modal flexible sensor of claim 1, wherein: The polyimide-MXene-bismuth telluride composite aerogel is a nano-sensitive material integrating pressure sensing, temperature sensing and infrared sensing; And / or, the pore size of the three-dimensional porous structure is 20-50 nm; And / or, the mass fraction of the polyimide is 10-20 wt%, the mass fraction of the MXene is 10-20 wt%, and the mass fraction of the bismuth telluride is 60-80 wt%.

3. The pressure-temperature-infrared multi-modal flexible sensor of claim 1, wherein: The flexible protective layer (1) is arranged on the top end surface of the second electrode layer, and the flexible substrate is arranged on the bottom end surface of the first electrode layer; And / or, the thickness of the flexible substrate layer (5) is 20-300 μm; And / or, the material of the flexible substrate layer (5) comprises at least any one of polyimide, polydimethylsiloxane, polyethylene terephthalate and polyethylene; And / or, the thickness of the sensitive layer (3) is 500-3000 μm; And / or, the thickness of the flexible protective layer (1) is 5-100 μm; And / or, the material of the flexible protective layer (1) has good biocompatibility, and the material of the flexible protective layer (1) comprises at least any one of polyvinyl alcohol and polydimethylsiloxane; And / or, the thickness of the first electrode layer (4) is 10-20 μm; And / or, the thickness of the second electrode layer (2) is 10-20 μm; And / or, the first electrode layer (4) and the second electrode layer (2) are both metal conductive electrode sheets, and the material of the first electrode layer (4) and the second electrode layer (2) comprises at least any one of gold, silver and copper; And / or, the flexible substrate layer (5) and the flexible protective layer (1) both have flexibility and adhesion.

4. The method of producing a pressure-temperature-infrared multimodal flexible sensor according to any one of claims 1 to 3, characterized in that, Comprise: providing a flexible substrate as a flexible substrate layer (5), and depositing a first electrode layer (4) on the surface of the flexible substrate layer (5); coating polyimide-MXene-bismuth telluride composite aerogel on the surface of the first electrode layer (4) to form a sensitive layer (3) with a three-dimensional porous structure; depositing a second electrode layer (2) on the surface of the sensitive layer (3); covering a flexible protective layer (1) on the surface of the second electrode layer (2) to obtain a pressure-temperature-infrared multi-mode flexible sensor.

5. The preparation method according to claim 4, characterized in that, The preparation method of the polyimide-MXene-bismuth telluride composite aerogel comprises: mixing tellurite, bismuth salt, surfactant and organic solvent uniformly to obtain a first precursor solution, uniformly dispersing the first precursor solution with MXene, and carrying out constant temperature reaction to complete bismuth telluride crystal growth to obtain an MXene-bismuth telluride composite; freezing the second precursor solution containing polyamide acid, MXene-bismuth telluride composite and solvent by liquid nitrogen, vacuum freeze-drying to obtain a precursor aerogel; annealing the precursor aerogel under an inert atmosphere to obtain a polyimide-MXene-bismuth telluride composite aerogel.

6. The production method according to claim 5, wherein Specifically comprising: After obtaining the first precursor solution, the pH value of the first precursor solution is adjusted to neutral, and then MXene is added and uniformly dispersed; Preferably, the temperature of the constant temperature reaction is 140-200℃, and the time is 4-8h; Preferably, the liquid-solid ratio of the first precursor solution to MXene is 100-1000:1 mL / g; Preferably, the mass ratio of tellurite, bismuth salt, surfactant and organic solvent is 1:(1-1.6):(0.5-0.8):(50-200); Preferably, the tellurite includes sodium tellurite; Preferably, the bismuth salt includes bismuth nitrate pentahydrate; Preferably, the surfactant includes polyvinylpyrrolidone; Preferably, the organic solvent includes ethylene glycol.

7. The preparation method according to claim 5, characterized in that, Specifically comprising: mixing the polyamide acid and the solvent with water uniformly to obtain a polyamide acid solution; ultrasonic treatment of the MXene-bismuth telluride composite with water to obtain a MXene-bismuth telluride composite dispersion liquid; mixing the polyamide acid solution and the MXene-bismuth telluride composite dispersion liquid uniformly to obtain the second precursor solution; Preferably, the mass ratio of polyamide acid, solvent and MXene-bismuth telluride composite is (0.2-0.6):(0.01-0.3):(0.01-0.1):(1-6); Preferably, the solvent includes triethylamine; And / or, the preparation method specifically comprises: freezing the second precursor solution by liquid nitrogen for 0.1-0.5 h to fix the three-dimensional network structure, and then vacuum freeze-drying at-50--25℃ and 0-20 Pa for 12-48 h to obtain the precursor aerogel.

8. The preparation method according to claim 5, characterized in that, The annealing process specifically comprises: first temperature holding at a first heating rate from room temperature to a first temperature; second temperature holding at a second heating rate from the first temperature to a second temperature; third temperature holding at a third heating rate from the second temperature to a third temperature; fourth temperature holding at a fourth heating rate from the third temperature to a fourth temperature; fifth temperature holding at a fifth heating rate from the fourth temperature to a fifth temperature; Preferably, the first heating rate is 0.5-5℃ / min, the first temperature is 60-90℃, and the first temperature holding time is 5-30 min; Preferably, the second heating rate is 0.5-3℃ / min, the second temperature is 100-140℃, and the second temperature holding time is 5-30 min; Preferably, the third heating rate is 0.5-5℃ / min, the third temperature is 140-180℃, and the third temperature holding time is 5-30 min; Preferably, the fourth temperature rising rate is 0.5-3 ℃ / min, the fourth temperature is 180-220 ℃, and the fourth holding time is 30-120 min; Preferably, the fifth temperature rising rate is 0.5-3 ℃ / min, the fifth temperature is 230-300 ℃, and the fifth holding time is 30-120 min.

9. Use of the pressure-temperature-infrared multimodal flexible sensor according to any one of claims 1-3 in the field of flexible sensing.

10. A pressure-temperature-infrared multi-modal sensing system, characterized in that, The pressure-temperature-infrared multimodal flexible sensor according to any one of claims 1-3; Preferably, the pressure-temperature-infrared multimodal sensing system has the function of sensing and responding to pressure, temperature and infrared without interference in contact or non-contact mode.

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