Temperature / pressure bimodal decoupling flexible sensor based on MXene-Ag2Se and preparation method thereof

Abstract

The invention discloses a temperature / pressure bimodal decoupling flexible sensor based on MXene-Ag2Se, and the sensor comprises a top single electrode and a bottom double-interdigital electrode, the top electrode is of a q-shaped structure, the bottom double-interdigital electrode is two interdigital electrodes which are arranged in a crossed manner, and the interdigital electrodes are of an F-shaped structure; the bottom double-interdigital electrodes are a pair of interdigital electrodes and are used for sensing pressure and sensing pressure applied externally based on the change of contact resistance, and when the pressure is applied to the sensor, the resistance between the electrodes is changed due to the microscopic deformation of the MXene-Ag2Se composite material, so that sensitive detection on a pressure signal is realized; the interdigital electrode structure can provide more electric field distribution, and the stability and repeatability of pressure signals are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible sensors, and specifically relates to a temperature / pressure dual-modal decoupling flexible sensor based on MXene-Ag2Se and a preparation method thereof. Background Art

[0002] Flexible sensors are sensors that can maintain normal operation under mechanical deformation conditions such as bending, stretching, or compression. Their lightweight, flexible, and deformable properties enable them to operate stably in complex working environments. Flexible sensors can efficiently and accurately detect a variety of physical quantities, of which temperature and pressure are the most common and widely used.

[0003] The research on flexible sensors is developing from single-modal perception to multi-modal perception. By integrating multiple functional materials and structural designs, it can achieve simultaneous detection and analysis of multiple external physical signals, thereby promoting flexible sensors to move towards a smarter and more integrated direction.

[0004] Although many researchers have developed different temperature / pressure dual-modal flexible sensors, there are still many challenges to be solved. First, in practical applications, the Seebeck coefficient of most existing materials used for flexible sensors is not high, resulting in low sensitivity of the sensor to temperature signals. Secondly, when temperature and pressure signals act at the same time, they often produce a coupling effect, resulting in signal coupling, which in turn affects the accuracy of the sensor. Although structural design can achieve physical signal isolation to a certain extent, it is still necessary to combine efficient signal decoupling algorithms during data processing, and improve the independent extraction capability of multimodal signals through multi-parameter fitting, machine learning and other methods. In addition, how to achieve a large-scale, low-cost, and repeatable manufacturing process system is also one of the important bottlenecks in promoting the practical application of such sensors. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a temperature / pressure dual-modal decoupling flexible sensor based on MXene-Ag2Se and a preparation method thereof, which can realize dual-modal decoupling detection of temperature signals and pressure signals, and solve the problems that the existing dual-modal flexible sensors have low sensitivity to temperature detection and insufficient decoupling performance.

[0006] To solve the above technical problems, the technical solution of the present invention is: a temperature and pressure dual-modal decoupling flexible sensor based on MXene-Ag2Se, including a top single electrode and a bottom double-finger electrode, the top electrode has a "q"-shaped structure, and the bottom double-finger electrode is two cross-arranged forked electrodes, and the forked electrode has an "F"-shaped structure; the bottom double-finger electrode is a pair of forked electrodes used for pressure sensing, which senses externally applied pressure based on the change in resistance between the electrodes. When pressure is applied to the sensor, the microscopic deformation of the MXene-Ag2Se composite material causes the resistance between the electrodes to change, thereby realizing sensitive detection of the pressure signal; the forked electrode structure can provide more electric field distribution, thereby improving the stability and repeatability of the pressure signal.

[0007] Preferably, one of the interdigitated electrodes in the bottom double-digit electrode and the top electrode together constitute a thermoelectric circuit to characterize the change in temperature gradient. The MXene-Ag2Se composite material has good thermoelectric conversion capability, and its temperature difference drives electron migration, thereby generating thermovoltage between the electrodes; when the external temperature changes or the sensor is locally heated, the potential difference of the thermoelectric circuit changes with the temperature gradient, thereby achieving highly sensitive temperature detection.

[0008] Preferably, the sensor improves the pressure detection sensitivity through the bottom interdigital electrode, and at the same time realizes the spatial separation of the temperature sensitive area and the pressure sensitive area in structure. The bottom double-interdigital electrode is the pressure sensitive area, and the area between the top single electrode and the bottom double-interdigital electrode is the temperature sensitive area, which effectively reduces the cross interference between the two and improves the temperature and pressure decoupling capability of the sensor.

[0009] Preferably, the change in resistance between the bottom bidigital electrodes can be used to characterize the pressure applied from the outside, while the temperature signal is detected through the change in the thermovoltage of the material.

[0010] The present invention also provides a method for preparing a temperature and pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se, comprising the following steps:

[0011] S1, using a porous substrate with high porosity as a flexible support material, immersing it in a chitosan solution, and utilizing the positively charged nature of chitosan to enhance the material's adhesion to subsequent functional layers;

[0012] S2, drying the chitosan to evenly cover the substrate surface, forming a stable chitosan layer;

[0013] S3, immersing the pretreated substrate in a MXene dispersion to uniformly load the two-dimensional MXene sheets on the substrate surface, and further enhancing their adhesion through vacuum drying.

[0014] S4. To improve the hydrophilicity of the material surface, plasma treatment is then used to increase the hydrophilicity of the substrate and eliminate the effect of MXene hydrophobicity on subsequent impregnation;

[0015] S5. During the silver nanoparticle deposition process, the substrate is first immersed in a glucose solution to enhance the reducing ability of the material;

[0016] S6, then add silver ammonia ion (Ag + ) solution and dried naturally under vacuum to ensure that the silver nanoparticles are evenly deposited on the surface of the MXene layer;

[0017] S7. After further vacuum drying, the sample is immersed in selenium solution to allow the Ag nanoparticles to 2- The reaction generates Ag2Se, thereby constructing the functional layer of the MXene-Ag2Se composite material;

[0018] S8. Finally, after vacuum drying, deionized water washing and secondary drying, a stable MXene / Ag2Se composite flexible sensor was obtained.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention provides a temperature / pressure dual-modal decoupling flexible sensor based on MXene-Ag2Se and a preparation method. A temperature and pressure dual-modal decoupling flexible sensor based on MXene-Ag2Se is designed and developed. While ensuring the flexibility of the sensor, it achieves highly sensitive and decoupled detection of temperature and pressure signals.

[0021] 2. Existing dual-mode sensors have poor separation of temperature and pressure signals, which affects the accuracy of signal recognition. The present invention adopts an innovative three-electrode structure design to improve the pressure detection sensitivity through the bottom interdigitated electrodes, while structurally achieving spatial separation of the temperature-sensitive area and the pressure-sensitive area, where the bottom surface is the pressure-sensitive area and the area between the upper and lower surfaces is the temperature-sensitive area, effectively reducing cross-interference between the two and improving the temperature-pressure decoupling capability of the sensor. The interdigitated electrode design optimizes the pressure detection area of ​​the sensor, improves its ability to perceive small external mechanical stresses, and further improves the pressure sensing accuracy.

[0022] 3. While changes in resistance or dielectric constant between the upper and lower electrodes can be used to characterize externally applied pressure, temperature signals are detected through the material's thermoelectric conversion properties or temperature-related impedance changes. This electrode structure can, to a certain extent, achieve simultaneous sensing of pressure and temperature. However, due to potential coupling between the signals, this can lead to interference between the pressure and temperature signals, affecting measurement accuracy. Therefore, this study optimized the traditional design and proposed a novel electrode structure to achieve efficient decoupling and sensitive detection of pressure and temperature signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a step diagram of the method for preparing a temperature / pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se of the present invention;

[0024] Figure 2 Schematic diagram of the three-electrode structure of the dual-mode flexible sensor of the present invention;

[0025] Figure 3 This is a schematic diagram of a pulse pressure detection application of a sensor according to a first embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of a finger temperature detection application of a sensor according to a second embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of a dual-mode array electronic skin according to a third embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the use of a dual-mode array electronic skin to detect a hot beaker in Example 3 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0030] Example 1

[0031] like Figure 1 As shown, the temperature / pressure dual-modal decoupling flexible sensor based on MXene-Ag2Se provided by the present invention includes a top single electrode and a bottom bidigital electrode. The top electrode has a "q"-shaped structure, and the bottom bidigital electrode is two cross-arranged bidigital electrodes, and the bidigital electrodes have an "F"-shaped structure. The bottom bidigital electrode is a pair of bidigital electrodes used for pressure sensing, which senses externally applied pressure based on the change in resistance between the electrodes. When pressure is applied to the sensor, the microscopic deformation of the MXene-Ag2Se composite material causes the resistance between the electrodes to change, thereby realizing sensitive detection of the pressure signal. The bidigital electrode structure can provide a larger electric field distribution, thereby improving the stability and repeatability of the pressure signal.

[0032] One of the interdigitated electrodes in the bottom bidigitated electrode, along with the top electrode, forms a thermoelectric circuit to characterize changes in temperature gradients. The MXene-Ag2Se composite material exhibits excellent thermoelectric conversion capabilities. The temperature difference drives electron migration, generating a thermovoltage between the electrodes. When the external temperature changes or the sensor is locally heated, the potential difference in the thermoelectric circuit changes with the temperature gradient, enabling highly sensitive temperature detection.

[0033] Compared with the traditional double-layer electrode structure, this design improves the signal response capability and sensor signal decoupling capability by separating the temperature and pressure sensitive areas.

[0034] The sensor improves the pressure detection sensitivity through the bottom interdigital electrode, and at the same time achieves spatial separation of the temperature sensitive area and the pressure sensitive area in structure. The bottom double-interdigitated electrode is the pressure sensitive area, and the area between the top single electrode and the bottom double-interdigitated electrode is the temperature sensitive area, which effectively reduces the cross-interference between the two and improves the temperature and pressure decoupling capability of the sensor.

[0035] The change in resistance between the bottom two-finger electrodes can be used to characterize the external pressure, while the temperature signal is detected through the change in the material's thermovoltage.

[0036] To address the low sensitivity of existing flexible dual-modal sensors in temperature detection, the present invention innovatively combines MXene on the surface of a melamine sponge substrate to in situ synthesize Ag2Se through a chemical reaction, thereby constructing a highly sensitive nanocomposite material.

[0037] The present invention also discloses a method for preparing a temperature and pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se, comprising the following steps:

[0038] S1, a porous substrate with high porosity is used as a flexible support material, which is immersed in a chitosan solution, and the positively charged property of chitosan is used to enhance the adhesion of the material to the subsequent functional layer.

[0039] In this example, the porous substrate is made of melamine sponge, and the subsequent functional layer is MXene.

[0040] S2. The chitosan is evenly covered on the surface of the substrate through drying to form a stable chitosan layer.

[0041] S3. Immerse the pretreated substrate in a MXene dispersion to uniformly load the two-dimensional MXene flakes on the substrate surface, and further enhance its adhesion through vacuum drying.

[0042] S4. To improve the hydrophilicity of the material surface, plasma treatment is then used to increase the hydrophilicity of the substrate and eliminate the effect of MXene hydrophobicity on subsequent impregnation. Plasma treatment is also known as PLASMA.

[0043] S5. During the silver nanoparticle deposition process, the substrate is first immersed in a glucose solution to enhance the reducing ability of the material.

[0044] S6, then add silver ammonia ion (Ag + ) solution and dried naturally under vacuum to ensure that silver nanoparticles are evenly deposited on the surface of the MXene layer.

[0045] S7. After further vacuum drying, the sample is immersed in selenium solution to allow the Ag nanoparticles to 2- The reaction generates Ag2Se, thereby constructing the functional layer of the MXene-Ag2Se composite material.

[0046] S8. Finally, after vacuum drying, deionized water washing and secondary drying, a stable MXene / Ag2Se composite flexible sensor was obtained.

[0047] The preparation method disclosed in the present invention combines solution impregnation, plasma modification and in-situ silver mirror reaction, so that the MXene / Ag2Se composite material can be evenly distributed on a flexible substrate while maintaining good conductivity and stability.

[0048] This paper proposes and implements a preparation method based on a combination of multi-step solution impregnation and surface modification. Specifically, it describes a method for preparing a temperature- and pressure-decoupled flexible sensor based on MXene-Ag2Se. This method successfully constructs a MXene / Ag2Se dual-modal flexible sensor with multifunctional responsiveness. This method systematically manipulates the structure and interface of a melamine sponge flexible substrate, including chitosan reinforcement, uniform MXene loading, plasma surface activation, in-situ silver deposition, and selenization. This method achieves the construction of a highly uniform, highly adherent, and multifunctional composite layer of conductive nanomaterials on a high-porosity support structure.

[0049] The preparation method of this invention not only improves the loading efficiency of nanomaterials and the stability of composite interfaces, but also effectively avoids the problems of coating peeling and response hysteresis that are common in traditional coating processes. By controlling the reaction conditions and the interface modification process, MXene and Ag2Se form a highly synergistic functional network on the material surface, endowing the sensor with highly sensitive responses to temperature, pressure, and ultraviolet signals. This method provides a new technical path for constructing flexible sensors with stable structures, diverse responses, and strong adaptability, and demonstrates good scalability and practical potential.

[0050] Existing dual-modal sensors have poor separation between temperature and pressure signals, affecting the accuracy of signal recognition. This invention innovatively proposes a three-electrode structural design, which improves pressure detection sensitivity through bottom-surface interdigitated electrodes. It also structurally separates the temperature-sensitive and pressure-sensitive areas, effectively reducing cross-interference between the two and enhancing the sensor's temperature-pressure decoupling capability. The interdigitated electrode design optimizes the sensor's pressure detection area, improving its ability to sense tiny external mechanical stresses and further enhancing pressure sensing accuracy.

[0051] Nanocomposites are developed for the three goals of temperature detection, pressure detection and decoupling. By optimizing the synthesis process of MXene / Ag2Se composites, the content of Ag2Se and its distribution on the MXene sheets are regulated to improve the thermoelectric properties and conductivity of the material.

[0052] A MXene / Ag2Se dual-modal flexible sensor was prepared by a multi-step solution impregnation and surface modification method to achieve sensitive detection of temperature, pressure and ultraviolet light signals. Figure 1 As shown in the figure, the entire preparation process includes substrate pretreatment, MXene loading, deposition of silver nanoparticles, selenization reaction and final drying treatment to ensure the uniformity of the material and the stability of the sensing performance.

[0053] In the specific use process of this embodiment, Figure 3 As shown, Figure 3 (a) is the installation position of the sensor pulse detection, (b) is the continuous pulse response signal measured by the sensor, (c) is a typical pulse waveform diagram, and (d) is a single pulse waveform measured by the sensor.

[0054] As an important physiological signal of the human cardiovascular system, the dynamic characteristics of the pulse wave can reflect key health indicators such as heart rate, vascular elasticity and blood pressure changes. Traditional rigid sensors have difficulty accurately capturing tiny and dynamic pulse pressure fluctuations due to their high material hardness and poor adhesion, especially the natural deformation of human skin during pulse beating. Based on this, the dual-modal flexible sensor designed by the present invention is integrated into the radial artery of the wrist ( Figure 3 (a) Leveraging its high sensitivity and ultrathin, flexible structure, a clamp-on lead enables real-time, noninvasive monitoring of pulse waveforms. Pulse signal detection relies on the tiny skin deformations caused by vascular pulsation. This deformation acts on the sensor surface, causing periodic changes in its resistance.

[0055] like Figure 3As shown in (c), the typical waveform characteristics of a human pulse signal include two main phases: systole and diastole. Systole (the blue area on the left) corresponds to the peak pressure when the heart pumps blood, while diastole (the purple area on the right) contains three characteristic peaks: P0, P1, and P2. P0 represents the main wave, P1 represents the tidal wave, and P3 represents the dicrotic wave, which reflects the influence of blood return and vascular compliance. Recording the pulse waveform through the sensor's pressure signal detection mechanism can help monitor human health.

[0056] like Figure 3 (b) and Figure 3 (c) Experimental results show that the sensor can clearly record the typical pulse waveform characteristics in the resting state, which is consistent with the theoretical pulse waveform trend, and clearly presents characteristic points such as P1 (main peak), P2 (reflected wave) and P3 (terminal wave), verifying the high-precision detection capability of the sensor. The elastic recovery characteristics of the flexible sponge substrate ensure long-term stable contact between the sensor and the skin interface, avoiding signal attenuation caused by loose fitting. This embodiment verifies the practical value of dual-modal sensors in cardiovascular health monitoring and provides a new solution for wearable devices to achieve high-precision pulse diagnosis.

[0057] Example 2

[0058] Compared with the first embodiment, this embodiment has the following differences:

[0059] In order to further develop the application capability of the invention in biological body temperature monitoring, a human finger temperature detection experiment was conducted. During the experiment, the sensor was fixed on the test platform and the subject's finger was made to touch the sensor surface to observe the real-time response of the sensor to the finger temperature change. Figure 4 As shown in the figure, the experiment uses a digital multimeter to record the thermal voltage signal of the sensor, and at the same time uses an infrared thermal imager to observe the finger temperature to further analyze the temperature detection performance of the sensor.

[0060] Figure 4 (a) is a photo of the sensor's finger temperature signal detection, (b) is a diagram of the human finger temperature signal measured by the sensor, and (c) is a diagram of the human finger temperature and ambient temperature.

[0061] Figure 4 (b) shows the temperature response signal measured by the sensor during finger contact. It can be observed that when a finger touches the sensor, the output voltage rises rapidly and stabilizes within a short period of time, indicating that the sensor can respond quickly and sensitively to changes in finger temperature. This temperature signal trend demonstrates that the excellent thermoelectric conversion effect of the MXene / Ag2Se composite material enables the dual-mode flexible sensor to effectively sense human body heat and generate a stable voltage signal.

[0062] The rest of this embodiment is the same as that of the first embodiment.

[0063] Example 3

[0064] Compared with the first embodiment, this embodiment has the following differences:

[0065] In order to verify the sensor's ability to simultaneously perceive temperature and pressure signals in complex environments, a dual-mode array electronic skin was designed and prepared. Its structural composition is as follows: Figure 5 As shown in Figure 2, the electronic skin consists of a flexible paper substrate, a conductive carbon paste electrode, a MXene-Ag2Se composite sensor (placed in a limiting layer to improve stability), an Ecoflex limiting layer, and copper connecting electrodes. The entire system adopts an array design, with each pixel unit able to respond simultaneously to temperature and pressure signals, forming a multi-point detection capability, giving the electronic skin high spatial resolution sensing capabilities.

[0066] Figure 5 In the figure, (a) is an introduction to the structural composition of the array-type electronic skin, and (b) is a real picture of the array-type electronic skin.

[0067] The MXene-Ag2Se composite sensor is used for dual-modal sensing of temperature and pressure: the thermoelectric properties of Ag2Se generate thermoelectric potential under temperature gradients, while the high conductivity of MXene enables sensitive response to pressure changes. An Ecoflex limiting layer ensures controlled deformation of the sensing element under external forces while also providing mechanical protection. The inclusion of a flexible paper substrate ensures the flexibility of the electronic skin, enabling it to conform to various surfaces and be used in wearable sensing applications. Figure 5 (b) shows a physical image of the arrayed electronic skin. The flexible paper is common A4 paper, onto which the arrayed interdigital electrodes are screen-printed. The Ecoflex stopper is fabricated using a 3D-printed template and then molded. The sensor contact bottom interdigital electrodes are placed within the stopper, and the copper electrodes on the sensor's top surface are electrically connected to the sensor using silver paste.

[0068] In order to verify the performance of the electronic skin in terms of simultaneous temperature and pressure perception, this embodiment conducted a sensing test under the action of a heat source. In the experiment, a beaker filled with hot water (40°C) was placed at different positions on the electronic skin, and the corresponding temperature and pressure distribution changes were recorded. The experimental results are shown in Figure 2. Figure 6 shown. Figure 6 (a) shows the temperature and pressure changes caused by a beaker filled with hot water acting on the upper right position, (b) shows the temperature and pressure changes caused by a beaker filled with hot water acting on the lower left position, and (c) shows the temperature and pressure changes caused by a beaker filled with hot water acting on the center position.

[0069] When the beaker was placed in the upper right corner of the array electronic skin, the temperature and pressure signals in this area increased significantly, which was manifested as a significant increase in temperature response (around 40°C). At the same time, the pressure signal in this area also changed significantly (>1.5). Since the hot water beaker not only applied a local temperature gradient, but also its weight applied mechanical stress to the area, the electronic skin successfully captured the synchronous changes in the dual-modal signals, while the signals in other unstressed areas remained at a low level. When the hot beaker acted on the lower left corner, the distribution of temperature and pressure signals changed accordingly. The maximum value of the temperature response remained at around 40°C, while the pressure distribution diagram showed that the pressure was mainly concentrated in the lower left area. Figure 6 Compared with the situation in Figure 2 (a), it can be clearly observed that after the heat source is loaded at different positions, the temperature and pressure signals of the electronic skin undergo position-dependent changes. When the hot beaker is applied to the central area of ​​the array electronic skin, the temperature and pressure signals show a symmetrical distribution, further indicating that the electronic skin can effectively capture the overall pressure and temperature changes. In addition, from the 3D bar graph of the temperature and pressure data, the electronic skin can accurately distinguish between temperature signals and pressure signals, and output independent response data respectively. This further confirms the temperature-pressure decoupling capability of the MXene-Ag2Se composite material, that is, the temperature signal mainly depends on the change of thermoelectric potential, while the pressure signal mainly depends on the change of contact resistance.

[0070] The rest of this embodiment is the same as that of the first embodiment.

[0071] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.

Claims

1. Temperature / pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se, characterized by: It includes a top single electrode and a bottom bidigital electrode. The top electrode has a "q"-shaped structure, and the bottom bidigital electrode is two cross-arranged bidigital electrodes, and the bidigital electrodes have an "F"-shaped structure. The bottom bidigital electrode is a pair of bidigital electrodes used for pressure sensing, which senses externally applied pressure based on the change in resistance between the electrodes. When pressure is applied to the sensor, the microscopic deformation of the MXene-Ag2Se composite material causes the resistance between the electrodes to change, thereby realizing sensitive detection of the pressure signal. The bidigital electrode structure can provide a larger electric field distribution, thereby improving the stability and repeatability of the pressure signal.

2. The temperature / pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se according to claim 1, characterized in that: One of the interdigitated electrodes in the bottom bidigitated electrode and the top electrode together form a thermoelectric loop to characterize the change in temperature gradient. The MXene-Ag2Se composite material has good thermoelectric conversion capabilities. Its temperature difference drives electron migration, thereby generating thermovoltage between the electrodes. When the external temperature changes or the sensor is locally heated, the potential difference of the thermoelectric circuit changes with the temperature gradient, achieving highly sensitive temperature detection.

3. The temperature / pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se according to claim 1, characterized in that: The sensor improves the pressure detection sensitivity through the bottom interdigital electrode, and at the same time achieves spatial separation of the temperature sensitive area and the pressure sensitive area in structure. The bottom double-interdigital electrode is the pressure sensitive area, and the area between the top single electrode and the bottom double-interdigital electrode is the temperature sensitive area, which effectively reduces the cross-interference between the two and improves the temperature and pressure decoupling capability of the sensor.

4. The temperature / pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se according to claim 1, characterized in that: The change in resistance between the bottom two-finger electrodes can be used to characterize the pressure applied by the outside, while the temperature signal is detected through the change in the thermovoltage of the material.

5. Preparation method of temperature / pressure dual-mode decoupling flexible sensor based on MXene-Ag2Se, characterized in that: The following steps are involved: S1, using a porous substrate with high porosity as a flexible support material, immersing it in a chitosan solution, and utilizing the positively charged nature of chitosan to enhance the material's adhesion to subsequent functional layers; S2, drying the chitosan to evenly cover the substrate surface, forming a stable chitosan layer; S3, immersing the pretreated substrate in a MXene dispersion to uniformly load the two-dimensional MXene sheets on the substrate surface, and further enhancing their adhesion through vacuum drying. S4. To improve the hydrophilicity of the material surface, plasma treatment is then used to increase the hydrophilicity of the substrate and eliminate the effect of MXene hydrophobicity on subsequent impregnation; S5. During the silver nanoparticle deposition process, the substrate is first immersed in a glucose solution to enhance the reducing ability of the material; S6, then add silver ammonia ion (Ag + ) solution and dried naturally under vacuum to ensure that the silver nanoparticles are evenly deposited on the surface of the MXene layer; S7. After further vacuum drying, the sample is immersed in selenium solution to allow the Ag nanoparticles to 2- The reaction generates Ag2Se, thereby constructing the functional layer of the MXene-Ag2Se composite material; S8. Finally, after vacuum drying, deionized water washing and secondary drying, a stable MXene / Ag2Se composite flexible sensor was obtained.

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