A thermoelectric-piezoelectric single-channel dual-parameter sensor based on te nanotubes and a manufacturing method thereof

Abstract

The present application relates to the technical field of sensor, in particular to a thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotube and a manufacturing method thereof.The sensor comprises a multilayer composite film structure, from bottom to top in turn: a polyimide flexible substrate, a lower electrode indium tin oxide conductive layer, a SiO2 dielectric layer, a Te nanotube film sensing layer, a polydimethylsiloxane packaging protective layer, and an upper electrode gold layer.The upper electrode gold layer and the lower electrode indium tin oxide conductive layer are respectively connected with a silver glue leading-out gold wire as the only output terminal.The polyimide flexible substrate serves as a flexible support, and the upper electrode gold layer and the lower electrode indium tin oxide conductive layer form a loop with an external circuit to output a signal.The thermoelectric-piezoelectric single-channel dual-parameter sensor can output thermoelectric-piezoelectric signals in a single channel at the same time, has excellent flexibility, a simple manufacturing method, low cost, can realize large-scale preparation and miniaturized application, and has great potential in the fields of medical health and human-computer interaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes and a manufacturing method thereof. BACKGROUND

[0002] In the face of an increasingly serious energy crisis, the exploration of green renewable energy has become an important proposition. Currently, mainstream green renewable energy is focused on macro applications, such as solar energy, wind energy, and water energy. Due to their low collection costs, they are widely used. However, in addition to these, there are some green renewable energies that are difficult to collect and can be used on a micro scale, such as various forms of heat energy and machinery that exist in living environments. On the other hand, with the continuous development of electronic devices, the development trend of flexible wearable devices is towards miniaturization, integration, and multifunctionality to monitor human health conditions. However, the traditional battery power supply method greatly limits the miniaturization of devices, so there is an urgent need for a self-powered multifunctional sensor that can utilize human body heat and motion mechanical energy for power supply.

[0003] Traditional flexible thermoelectric-piezoelectric dual sensors are integrated by three-dimensional structure design of one thermoelectric material and one piezoelectric material to realize composite dual-parameter sensing. They are mostly dual-channel outputs, separately obtaining thermoelectric and piezoelectric signals. The structure is complex, there are more than one group of electrodes, which affects stability, the preparation process is complex, the cost is high, and it limits the miniaturization of the device. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes and a manufacturing method thereof. The sensor can simultaneously output linearly superimposed thermoelectric-piezoelectric signals in a single channel, that is, it has the ability to monitor temperature and pressure simultaneously, and does not require an external power supply. The preparation method is simple, low in cost, and single in raw materials. The element Te is used for thermal evaporation to prepare nanotubes, which simultaneously serve as thermoelectric and piezoelectric materials. Signal collection is completed through a simple multi-layer structure design. There is only one group of electrodes for single-channel simultaneous output of thermoelectric-piezoelectric signals. Stable thermoelectric-piezoelectric coupling signals can be measured with a multimeter without amplification.

[0005] The technical scheme of the present application is:

[0006] A thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes, comprising a multilayer composite film structure, from bottom to top: a polyimide flexible substrate, a lower electrode indium tin oxide conductive layer, a SiO2 dielectric layer, a Te nanotube thin film sensing layer, a polydimethylsiloxane encapsulation protective layer, and an upper electrode gold layer; the upper electrode gold layer and the lower electrode indium tin oxide conductive layer are respectively connected to a gold wire as the only output terminal through silver glue; the polyimide flexible substrate serves as a flexible support, and the upper electrode gold layer and the lower electrode indium tin oxide conductive layer form a loop with an external circuit to output a signal.

[0007] The thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes is prepared by sequentially depositing a lower electrode indium tin oxide conductive layer, a SiO2 dielectric layer, and a Te nanotube thin film sensing layer on a polyimide flexible substrate, spin-coating a polydimethylsiloxane encapsulation protective layer on the Te nanotube thin film sensing layer, and depositing an upper electrode gold layer on the polydimethylsiloxane encapsulation protective layer; one end of one gold wire is fixed on the upper electrode gold layer through silver glue, and one end of the other gold wire is fixed on the lower electrode indium tin oxide conductive layer through silver glue; the free ends of the two gold wires are the output terminals of the sensor, and the gold wires on the upper electrode gold layer and the lower electrode indium tin oxide conductive layer are convenient for connecting to a test device as output terminals.

[0008] The thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes has a polyimide flexible substrate with a thickness of 25-75 μm, a lower electrode indium tin oxide conductive layer with a thickness of 90-110 nm, a SiO2 dielectric layer with a thickness of 90-110 nm, a polydimethylsiloxane encapsulation protective layer with a thickness of 2-3 μm, and an upper electrode gold layer with a thickness of 80-120 nm.

[0009] The thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes has a Te nanotube thin film sensing layer prepared by a tubular furnace thermal evaporation method, wherein the Te nanotubes have a diameter of 200-400 nm, a length of 4-6 μm, and a wall thickness of 40-60 nm, and the C axis of the Te nanotubes forms an angle of 0-45° with the polyimide flexible substrate.

[0010] The preparation method of the thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes comprises the following steps:

[0011] Step 1: sequentially depositing a conductive layer and a dielectric layer on a polyimide flexible substrate by using a magnetron sputtering technique;

[0012] Step 2: depositing a Te nanotube thin film sensing layer by a tubular furnace thermal evaporation method;

[0013] Step 3: spin-coating a polydimethylsiloxane encapsulation protective layer on the Te nanotube thin film sensing layer;

[0014] Step 4: Magnetron sputtering mask deposition of 80-120 nm thick upper electrode gold layer, the area of the upper electrode gold layer is smaller than that of the lower electrode indium tin oxide conductive layer, to avoid the upper and lower electrodes from being in contact and conducting;

[0015] Step 5: Remove the mask, take the polyimide flexible substrate off the fixed glass substrate, and peel off the polyimide mask tape to expose the reserved lower electrode indium tin oxide. Fix one end of the gold wire on the upper and lower electrodes with silver glue, and the free ends of the two gold wires are the output ends of the sensor.

[0016] The preparation method of the Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor, step 1 is specifically:

[0017] Step 1.1: Cut a 25-75 μm thick polyimide flexible substrate into a 1 cm x 2 cm rectangle, and ultrasonically clean it with acetone and alcohol for 20-40 min, and finally blow it clean with nitrogen for standby;

[0018] Step 1.2: Use magnetron sputtering technology to mask deposit a 90-110 nm thick lower electrode indium tin oxide conductive layer and a 90-110 nm thick SiO2 dielectric layer on the polyimide flexible substrate.

[0019] The growth process of the Te nanotube in step 2 of the preparation method of the Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor is specifically:

[0020] Step 2.1: Place the quartz boat loaded with Te powder in the heating zone of the tube furnace;

[0021] Step 2.2: Fix the prepared polyimide flexible substrate on a glass sheet, that is, paste polyimide mask tape on the 2-4 mm wide area on both sides of the polyimide flexible substrate to reserve the lower electrode, and paste polyimide mask tape on the four peripheral edges of the polyimide flexible substrate to prevent the edge of the film from depositing Te nanotubes and conducting with the lower electrode indium tin oxide, and place it in the insulation zone of the tube furnace, with the quartz boat being 20-25 cm away from the polyimide flexible substrate;

[0022] Step 2.3: Close the port of the tube furnace, start the mechanical pump to pump the pressure in the tube furnace to 1-3 Pa, then start the molecular pump to pump the pressure in the tube furnace to 5 x 10 -4 Pa, turn off the molecular pump, and introduce 30-50 sccm of argon to maintain the pressure in the tube furnace at 20-30 Pa;

[0023] Step 2.4: Start the heating program, heat at a rate of 10-20 ℃ / min to 280-320 ℃, then heat at a rate of 4-6 ℃ / min to 340-360 ℃, and cool down with the furnace after 18-22 min of heat preservation to obtain a Te nanotube film sensing layer.

[0024] The preparation method of the thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes, step 3 is specifically:

[0025] Step 3.1: After taking out the polyimide flexible substrate on which the Te nanotube thin film sensing layer is deposited, the polyimide mask tape in step 2 is removed, and the polyimide mask tape is reattached to the position of 1-3 mm wide on both sides of the polyimide flexible substrate to avoid the thin film being taken up when the mask tape is removed subsequently;

[0026] Step 3.2: The polydimethylsiloxane solution is configured, the main agent and the curing agent are uniformly mixed in a weight ratio of 10:1, and are placed in a vacuum box for 20-40 min for degassing, and are poured into a syringe for standby;

[0027] Step 3.3: The glass sheet with the polyimide flexible substrate attached in step 2 is adsorbed at the center of the spin coater, and the polydimethylsiloxane solution is dropped on the Te nanotube thin film sensing layer, and is first rotated at a low speed of 3000-5000 r / min for 10-15 s, and then rotated at a high speed of 7000-9000 r / min for 20-40 s, until the polydimethylsiloxane solution is uniformly coated on the Te nanotube thin film sensing layer;

[0028] Step 3.4: The glass sheet is taken down and placed on a heating table at 140-160 DEG C for 18-22 min, and after curing, the thickness of the polydimethylsiloxane is 2-3 microns.

[0029] In step 2 of the preparation method of the thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes, Te nanotubes with intrinsic thermoelectric and piezoelectric effects are used as thermoelectric-piezoelectric sensing units.

[0030] In step 2 of the preparation method of the thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotubes, Te nanotubes are prepared by low-temperature thermal evaporation of Te powder.

[0031] The design idea of the present application is as follows:

[0032] The piezoelectric signal is derived from the asymmetric crystal structure of the Te nanotube, and the potential difference is generated by the separation of the positive and negative charge centers under the radial external force. The thermoelectric signal is derived from the carrier movement driven by the temperature difference to generate the potential difference at the two ends of the device. When the resistance of the upper and lower electrodes of the thin film is low, the carriers can pass through the dielectric layer, and the out-of-plane temperature difference is easily established due to the multi-layer structure and the special structure of the Te nanotube, and the response speed is fast, but the charge is easily leaked, and the piezoelectric signal cannot be generated. When the resistance increases to a certain value, the carriers cannot pass through the dielectric layer, and the out-of-plane thermoelectric performance is lost, but the piezoelectric signal is enhanced due to the increased ability to prevent charge leakage. When the resistance is between the two, the thermoelectric and piezoelectric signals are simultaneously generated, and the magnitudes are comparable and linearly superimposed. By adjusting the growth parameters of the Te nanotube, the thickness of the SiO2 dielectric layer, the thickness of the polydimethylsiloxane (PDMS) encapsulation protective layer and the properties of each film layer, the output type of the device can be adjusted by changing the resistance value.

[0033] Based on the above design guiding ideology, the application successfully manufactures a thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotube and a manufacturing method thereof, and can basically realize the thermoelectric-piezoelectric single-channel dual-parameter sensing function. The sensor includes a multi-layer composite film structure, from bottom to top: a polyimide (PI) flexible substrate, a lower electrode indium tin oxide (ITO) conductive layer, a SiO2 dielectric layer, a Te nanotube thin film sensing layer, a polydimethylsiloxane encapsulation protective layer, and an upper electrode gold layer. The gold wires of the upper and lower electrodes are respectively led out as the only output end. The polyimide flexible substrate provides flexible support, and the upper and lower electrode layers form a loop with the external circuit to output signals; the SiO2 dielectric layer of a certain thickness can block the leakage of induced charges in the electrode while allowing part of the carriers to pass through to simultaneously output piezoelectric-thermoelectric signals; the Te nanotube thin film sensing layer is formed by interweaving Te nanotubes with a large aspect ratio, and has high piezoelectric coefficients and Seebeck coefficients. The C axis of the Te nanotube forms an angle of 0-45° with the polyimide flexible substrate, which is conducive to generating piezoelectric signals under radial stress and generating out-of-plane thermoelectric signals along the longitudinal direction; the polydimethylsiloxane encapsulation protective layer is spin-coated on the Te nanotube, which can play a similar role as SiO2 as a dielectric layer, and can also fill the gap to fix and protect the device and improve the stability of the device; the gold wires of the upper and lower electrodes are used as the output end to facilitate the connection of the test equipment.

[0034] The thermoelectric-piezoelectric single-channel dual-parameter sensor based on Te nanotube and the manufacturing method thereof have at least the following advantages and beneficial effects:

[0035] 1. The Te nanotube thin film sensing layer of the dual-parameter sensor has high piezoelectric coefficients and Seebeck coefficients, and the high surface area is conducive to the electrical transport performance.

[0036] 2, The Te nanotube C axis of the double-parameter sensor of the application forms an angle of 0-45° with the polyimide flexible substrate, which is conducive to generating piezoelectric signals under radial stress and generating out-of-plane thermoelectric signals along the longitudinal direction. The multi-layer structure design is conducive to the establishment of the out-of-plane temperature difference of the Te nanotube while maintaining the piezoelectric performance, greatly improving the response time and recovery time of the temperature sensor.

[0037] 3, The components used in the double-parameter sensor of the application have good flexibility, so that it can be completely attached to a curved surface, and sensing on various irregular contact surfaces such as human body surfaces can be realized.

[0038] 4, The double-parameter sensor of the application reduces the design of the electrode, simplifies the structure, improves the reliability, and provides a new idea for the integration and miniaturization of the sensor, that is, a single material single channel realizes multifunctional self-driven sensing.

[0039] 5, The preparation method used in the application is simple, green and environmentally friendly, and can be applied to large-scale applications. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a structure exploded view of a thermoelectric-piezoelectric single-channel double-parameter sensor based on Te nanotubes.

[0041] Figure 2 is a structure front view of a thermoelectric-piezoelectric single-channel double-parameter sensor based on Te nanotubes.

[0042] Figures 1-2 In the figure, 1 is a polyimide flexible substrate, 2 is a lower electrode indium tin oxide conductive layer, 3 is a SiO2 dielectric layer, 4 is a Te nanotube thin film sensing layer, 5 is a polydimethylsiloxane packaging protective layer, 6 is an upper electrode gold layer, 7 is silver glue, 8 is a gold wire, and 9 is a Te nanotube.

[0043] Figure 3 is a flowchart of a manufacturing method of a thermoelectric-piezoelectric single-channel double-parameter sensor based on Te nanotubes.

[0044] Figure 4 is an electron scanning diagram of a Te nanotube thin film sensing layer of a thermoelectric-piezoelectric single-channel double-parameter sensor based on Te nanotubes.

[0045] Figure 5 is an electron scanning diagram of a Te nanotube thin film sensing layer of a thermoelectric-piezoelectric single-channel double-parameter sensor based on Te nanotubes after spin coating PDMS. DETAILED DESCRIPTION

[0046] In the following, a thermoelectric-piezoelectric single-channel double-parameter sensor based on Te nanotubes and a manufacturing method thereof will be described in detail in combination with the drawings and examples.

[0047] As shown in Figure 1 and Figure 2 The present application is based on a thermoelectric-piezoelectric single-channel dual-parameter sensor of Te nanotube, which comprises a polyimide flexible substrate 1, a lower electrode indium tin oxide conductive layer 2, a SiO2 dielectric layer 3, a Te nanotube thin film sensing layer 4, a polydimethylsiloxane packaging protective layer 5, an upper electrode gold layer 6, silver glue 7, and gold wire 8. The sensor is a multilayer composite film structure, and from bottom to top, it is sequentially polyimide flexible substrate 1, lower electrode indium tin oxide conductive layer 2, SiO2 dielectric layer 3, Te nanotube thin film sensing layer 4, polydimethylsiloxane packaging protective layer 5, and upper electrode gold layer 6. The upper electrode gold layer 6 and the lower electrode indium tin oxide conductive layer 2 are respectively connected to the gold wire 8 through the silver glue 7 as the only output terminal. The polyimide flexible substrate 1 provides flexible support, and the upper electrode gold layer 6 and the lower electrode indium tin oxide conductive layer 2 form a loop with the external circuit to output signals.

[0048] The lower electrode indium tin oxide conductive layer 2, the SiO2 dielectric layer 3, and the Te nanotube thin film sensing layer 4 are sequentially deposited on the polyimide flexible substrate 1, the polydimethylsiloxane packaging protective layer 5 is spin-coated on the Te nanotube thin film sensing layer 4, and the upper electrode gold layer 6 is deposited on the polydimethylsiloxane packaging protective layer 5. The area of the upper electrode gold layer 6 is slightly smaller than that of the lower electrode indium tin oxide conductive layer 2 to avoid the upper and lower electrodes from being in contact. One end of one gold wire 8 is fixed on the upper electrode gold layer 6 through the silver glue 7, and one end of the other gold wire 8 is fixed on the lower electrode indium tin oxide conductive layer 2 through the silver glue 7. The free ends of the two gold wires 8 are the output terminals of the sensor, and the gold wires on the upper electrode gold layer 6 and the lower electrode indium tin oxide conductive layer 2 are convenient for connecting to the test equipment as the output terminals.

[0049] The thickness of the polyimide flexible substrate 1 is 40-60 μm, the thickness of the lower electrode indium tin oxide conductive layer 2 is 90-110 nm, the thickness of the SiO2 dielectric layer 3 is 90-110 nm, the thickness of the polydimethylsiloxane packaging protective layer 5 is 2-3 μm, and the thickness of the upper electrode gold layer 6 is 80-120 nm. The Te nanotube thin film sensing layer 4 is formed by interweaving Te nanotubes 9 with a diameter of 200-400 nm, a length of 4-6 μm, and a wall thickness of 40-60 nm. The Te nanotube thin film sensing layer 4 has high piezoelectric coefficient and Seebeck coefficient, the C axis of the Te nanotube 9 forms an angle of 0-45° with the polyimide flexible substrate 1, which is conducive to generating piezoelectric signals under radial stress and generating out-of-plane thermoelectric signals along the longitudinal direction.

[0050] As shown in Figure 3 The preparation method of the present application is as follows:

[0051] Step 1: Masked deposition of conductive layer and dielectric layer on polyimide flexible substrate by magnetron sputtering technology.

[0052] Step 1.1: Cut 50 μm thick polyimide (Kapton) film into 1 cm x 2 cm rectangle, ultrasonic cleaning with acetone, alcohol for 30 min, and finally blow clean with nitrogen for standby.

[0053] Step 1.2: Masked deposition of 100 nm lower electrode indium tin oxide conductive layer and 100 nm SiO2 dielectric layer on polyimide flexible substrate by magnetron sputtering technology, mask the side surface to avoid polyimide flexible substrate side surface also plated with plating layer.

[0054] Step 2: Te nanotube thin film sensing layer is deposited by tube furnace thermal evaporation.

[0055] Step 2.1: Put the quartz boat loaded with 0.1 g of high purity Te powder (purity of 99.999wt%) into the heating zone of the tube furnace.

[0056] Step 2.2: Fix the prepared polyimide flexible substrate on the glass sheet, that is, paste polyimide masking tape on both sides of the polyimide flexible substrate 3 mm wide area to reserve the lower electrode indium tin oxide conductive layer, and paste polyimide masking tape on the four edges of the polyimide flexible substrate to prevent the edge of the polyimide flexible substrate from depositing Te nanotube and conducting with the lower electrode indium tin oxide conductive layer, and put it into the insulation zone of the tube furnace, with the quartz boat and the polyimide flexible substrate 22 cm apart.

[0057] Step 2.3: Close the port of the tube furnace, start the mechanical pump to pump the pressure in the tube furnace to 2 Pa, then open the molecular pump to pump the pressure in the tube furnace to 3 x 10 -4 Pa, close the molecular pump, and introduce 40 sccm of high purity argon (purity of 99.999vol%) to maintain the pressure in the tube furnace at 25 Pa.

[0058] Step 2.4: Start the heating program, heat to 300℃ at a rate of 15℃ / min, then heat to 350℃ at a rate of 5℃ / min, keep for 20 min, and then cool down with the furnace. The obtained Te nanotube thin film sensing layer is composed of Te nanotubes with diameter of 200-400 nm, length of 4-6 μm, and wall thickness of 40-60 nm, which are interwoven with each other, and have high piezoelectric coefficient and Seebeck coefficient. The C axis of the Te nanotube forms an angle of 0-45° with the polyimide flexible substrate, which is conducive to generating piezoelectric signal under radial stress and out-of-plane thermoelectric signal along the longitudinal direction.

[0059] Step 3: Spin-coat polydimethylsiloxane encapsulation protection layer on the Te nanotube thin film sensing layer.

[0060] Step 3.1: After the polyimide flexible substrate on which the Te nanotube thin film sensing layer is deposited is taken out, the polyimide mask tape of step 2 is removed, and the polyimide mask tape is reattached to the polyimide flexible substrate at a position 2 mm wide on both sides to avoid the thin film being taken off when the mask tape is removed later.

[0061] Step 3.2: The polydimethylsiloxane solution is prepared by uniformly mixing the main agent (polydimethylsiloxane) and the curing agent (conventional platinum catalyst) at a weight ratio of 10:1, degassing in a vacuum box for 30 min, and pouring into a syringe for standby.

[0062] Step 3.3: The glass sheet with the polyimide flexible substrate attached in step 2 is adsorbed at the center of the spin coater, and 0.1 mL of polydimethylsiloxane is dropped on the Te nanotube thin film sensing layer. First, it is rotated at a low speed of 4000 r / min for 12 s, and then at a high speed of 8000 r / min for 30 s, until the polydimethylsiloxane is uniformly coated on the Te nanotube thin film sensing layer.

[0063] Step 3.4: The glass sheet is taken off and placed on a heating table at 150°C for 20 min. After curing, the thickness of the polydimethylsiloxane is 2-3 μm.

[0064] Step 4: A mask is used to deposit a 100 nm thick gold layer as the upper electrode. The area of the upper electrode gold layer is slightly smaller than that of the lower electrode indium tin oxide conductive layer to avoid the upper and lower electrodes being in contact and conducting.

[0065] Step 5: The mask is removed, the polyimide flexible substrate is taken off from the fixed glass substrate, and the polyimide mask tape is removed to expose the reserved lower electrode indium tin oxide conductive layer. The gold wires are fixed at one end on the upper and lower electrodes using silver glue, and the free ends of the two gold wires are the output ends of the sensor.

[0066] After the above steps, the required Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor is prepared. The sensor prepared by this method has excellent flexibility and stability, is suitable for large-scale and miniaturized preparation, and benefits from the intrinsic properties of Te nanotubes, which can simultaneously output linearly superimposed thermoelectric-piezoelectric signals in a single channel.

[0067] In the following, the content of the application is further explained or illustrated by examples.

[0068] Example 1: Sensing the size and rate of deformation

[0069] The Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor of the present application is placed on a 1mm-thick polyvinyl chloride (PVC) plate, one end is fixed, and the free end of the PVC plate is moved by a linear motor driving a limiting rod, so that a tensile or compressive stress is applied to the device, at this time, a piezoelectric signal about the motor movement direction, speed, and movement amplitude can be obtained from a multimeter simultaneously, the polarity of the signal is reversed with the form of the stress, and the amplitude of the signal increases with the strain size and strain rate.

[0070] Example 2: sensing specific local temperature

[0071] The Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor of the present application is placed on a 1mm-thick PVC plate, one end is fixed, and a heat source is placed 1-2mm above the device, so that there is an out-of-plane temperature difference between the upper surface of the device and the lower surface of the sensing layer Te nanotube, at this time, a thermoelectric signal related to the temperature of the heat source can be obtained from a multimeter simultaneously, and the larger the temperature difference, the larger the signal amplitude.

[0072] Example 3: sensing deformation and local temperature

[0073] The Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor of the present application is placed on a 1mm-thick PVC plate, one end is fixed, and the free end of the PVC plate is moved by a linear motor driving a limiting rod, so that a tensile or compressive stress is applied to the device, at the same time, a heat source is placed 1-2mm above the device, so that there is an out-of-plane temperature difference between the upper surface of the device and the lower surface of the sensing layer Te nanotube, at this time, a thermoelectric-piezoelectric coupling signal related to the motor movement direction, speed, and movement amplitude and the temperature of the heat source can be obtained from a multimeter simultaneously, which is linearly superimposed.

[0074] Example 4: sensing the bending angle and temperature of a human finger joint

[0075] The Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor of the present application is attached to the finger joint, different bending degrees of the finger will bring different sizes of strain, different bending speeds will bring different strain rates, and there is a temperature difference between the finger temperature and the air temperature, so when the finger is bent, a thermoelectric-piezoelectric coupling signal of the finger bending speed, bending angle, and finger temperature (room temperature constant) can be obtained from a multimeter.

[0076] As shown in Figure 4 the electronic scanning diagram of the Te nanotube film sensing layer of a Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor, which is Figure 4 It can be seen that the Te nanotubes prepared by the method have good crystalline quality, large aspect ratio, uniform size, and interweave into a film rather than perpendicular to the substrate, which is conducive to the generation of piezoelectric signals.

[0077] As shown in Figure 5As shown, an electronic scanning diagram of a Te nanotube film sensing layer of a Te nanotube-based thermoelectric-piezoelectric single-channel dual-parameter sensor after spin coating PDMS, Figure 5 It can be seen that the PDMS fills the pores between the Te nanotubes, and part of the end of the Te nanotubes is exposed, providing a channel for the transmission of thermoelectric signals.

[0078] The implementation results show that the thermoelectric-piezoelectric single-channel dual-parameter sensor can simultaneously output thermoelectric-piezoelectric signals in a single channel, has excellent flexibility, a simple preparation method, low cost, can realize large-scale preparation and miniaturized application, and has great potential in the fields of medical health and human-computer interaction.

[0079] The above only describes the preferred embodiments of the present application and is not intended to limit the idea of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a Te-nanotube-based pyroelectric-piezoelectric single-channel dual-parameter sensor, characterized by, The sensor comprises a multilayer composite film structure, from bottom to top in turn: polyimide flexible substrate, lower electrode indium tin oxide conductive layer, SiO2 dielectric layer, Te nanotube film sensing layer, polydimethylsiloxane encapsulation protective layer, upper electrode gold layer, upper electrode gold layer, lower electrode indium tin oxide conductive layer is respectively led out gold wire as the only output terminal through silver glue; the polyimide flexible substrate is used as a flexible support, and the upper electrode gold layer and the lower electrode indium tin oxide conductive layer form a loop with an external circuit to output a signal; the preparation method of the sensor comprises the following steps: Step 1: using the magnetron sputtering technology, the lower electrode indium tin oxide conductive layer and the SiO2 dielectric layer are sequentially deposited on the polyimide flexible substrate through mask film deposition; Step 2: Te nanotube film sensing layer is prepared by tube furnace thermal evaporation deposition; Step 3: polydimethylsiloxane encapsulation protective layer is spin-coated on the Te nanotube film sensing layer; Step 4: 80-120 nm thick upper electrode gold layer is prepared by magnetron sputtering mask film deposition, the area of the upper electrode gold layer is smaller than that of the lower electrode indium tin oxide conductive layer, so as to avoid the upper and lower electrodes from being in contact and conducting; Step 5: the mask film is removed, the polyimide flexible substrate is taken off from the fixed glass substrate, the polyimide mask adhesive tape is removed to expose the reserved lower electrode indium tin oxide, and one end of the gold wire is fixed on the upper and lower electrodes respectively by using silver glue, and the free ends of the two gold wires are the output terminals of the sensor.

2. The preparation method of the Te-nanotube-based pyroelectric- piezoelectric single-channel dual-parameter sensor according to claim 1, wherein, Step 1 specifically comprises: Step 1.1: the 25-75 mu m thick polyimide flexible substrate is cut into a 1 cm*2 cm rectangle, and is sequentially ultrasonically cleaned with acetone and alcohol for 20-40 min, and finally is blown clean with nitrogen for standby; Step 1.2: using the magnetron sputtering technology, the lower electrode indium tin oxide conductive layer with a thickness of 90-110 nm and the SiO2 dielectric layer with a thickness of 90-110 nm are sequentially deposited on the polyimide flexible substrate through mask film deposition.

3. The method for fabricating a Te-nanotube-based pyroelectric- piezoelectric single-channel dual-parameter sensor according to claim 1, wherein The growth process of the Te nanotube in step 2 specifically comprises: Step 2.1: the quartz boat loaded with Te powder is placed in the heating zone of the tube furnace; Step 2.2: the prepared polyimide flexible substrate is fixed on the glass sheet, that is, the polyimide mask adhesive tape is pasted on the two sides of the polyimide flexible substrate with a width of 2-4 mm to reserve the lower electrode, and the polyimide mask adhesive tape is pasted on the four edges of the polyimide flexible substrate to prevent the edge of the film from depositing Te nanotube and being in contact with the lower electrode indium tin oxide, and the quartz boat and the polyimide flexible substrate are 20-25 cm apart; Step 2.3: Close the tube furnace port, start the mechanical pump to pump the pressure in the tube furnace to 1~3 Pa, and then open the molecular pump to pump the pressure in the tube furnace to 5x10 -4 Pa or below, close the molecular pump, and introduce 30~50 sccm of argon to maintain the pressure in the tube furnace at 20~30 Pa; Step 2.4: start the heating program, heat to 280-320 DEG C at a heating rate of 10-20 DEG C / min, then heat to 340-360 DEG C at a heating rate of 4-6 DEG C / min, and cool down with the furnace after keeping the temperature for 18-22 min, to obtain the Te nanotube film sensing layer.

4. The method for preparing a Te-nanotube-based pyroelectric- piezoelectric single-channel dual-parameter sensor according to claim 3, wherein In step 2, the Te nanotube film sensing layer is formed by the interweaving of Te nanotubes with a diameter of 200-400 nm, a length of 4-6 mu m and a wall thickness of 40-60 nm, and the C axis of the Te nanotube forms an angle of 0-45 DEG with the polyimide flexible substrate.

5. The method of claim 1, wherein the Te-nanotube-based pyroelectric- piezoelectric single-channel dual-parameter sensor is prepared by the steps of: Step 3 specifically comprises: Step 3.1: After the polyimide flexible substrate on which the Te nanotube thin film sensing layer is deposited is taken out, the polyimide mask tape in step 2 is removed, and the polyimide mask tape is reattached to the polyimide flexible substrate on both sides at a width of 1-3 mm to avoid the thin film being taken away when the mask tape is removed subsequently; Step 3.2: A polydimethylsiloxane solution is prepared, the main agent and the curing agent are uniformly mixed at a weight ratio of 10:1, and the mixture is placed in a vacuum box for 20-40 min to remove gas, and then poured into a syringe for standby; Step 3.3: The glass sheet with the polyimide flexible substrate attached in step 2 is adsorbed at the center of the spin coater, and the polydimethylsiloxane solution is dropped on the Te nanotube thin film sensing layer, and then rotated at a low speed of 3000-5000 r / min for 10-15 s, and then rotated at a high speed of 7000-9000 r / min for 20-40 s, until the polydimethylsiloxane solution is uniformly coated on the Te nanotube thin film sensing layer; Step 3.4: The glass sheet is taken out and placed on a heating table at 140-160℃ for 18-22 min, and after curing, the thickness of the polydimethylsiloxane is 2-3 μm.

6. The method of claim 1, wherein the Te-nanotube-based pyroelectric- piezoelectric single-channel dual-parameter sensor is prepared by the steps of: In step 2, Te nanotubes with intrinsic thermoelectric and piezoelectric effects are used as thermoelectric-piezoelectric sensing units.

7. The method for fabricating a single-channel dual-parameter sensor based on Te nanotubes as described in claim 1, characterized in that, In step 2, the Te nanotubes are prepared by low-temperature thermal evaporation of Te powder.

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