CN107132248B - A kind of self-powered gas sensor and preparation method thereof - Google Patents

Abstract

The invention provides a self-powered sensor and a preparation method thereof, belonging to the technical field of sensors. The structure of the present invention includes, from bottom to top, a stacked porous substrate, a first silver nanowire film, a P-type porous conductive polymer, a porous pyroelectric film, an N-type porous conductive polymer and a second silver nanowire film. The self-energy-supplying sensor of the present invention adopts porous pyroelectric film material as both a sensitive unit and an energy acquisition unit, thereby avoiding the film-forming process mismatch, film-forming non-uniformity and compatibility between different functional films when preparing different functional films. Bad problem; the device structure of the present invention is reasonably designed, which can synergistically realize energy collection and generate gas-sensing signals, so that the device structure is highly integrated and the sensitivity of the gas-sensing unit is improved; in addition, the preparation process of the invention is simple and controllable, and the cost is low. It has broad application prospects in flexible electronic devices.

Description

A kind of self-powered gas sensor and preparation method thereof

technical field

The invention belongs to the technical field of sensors, and in particular relates to a self-powered gas sensor integrating a gas sensing unit and an energy storage unit and a preparation method thereof.

Background technique

Sensors have always been widely used electronic devices and play an important role in people's production and life. In recent years, with the rapid development of nanotechnology, the miniaturization of devices has become the mainstream development trend. However, the miniaturization of devices also limits the volume of power supply equipment. As traditional batteries are used as power supply equipment, small size means small storage capacity. Once the charge is exhausted, the device loses functionality and must be replaced to maintain its specific function. On the one hand, this greatly limits the service life of the device. On the other hand, because most wireless sensor networks work in an unattended state for a long time, due to the large number of network nodes, the wide distribution area, and the complex working environment, if the battery replacement is used. Supplementing energy to nodes in this way will cause the system to fail to work properly due to untimely energy replenishment or failure to replace batteries in many widely distributed network nodes, thereby affecting the reliability of information acquisition. The endurance of the power supply unit of the micro-device is extremely important in practical applications, and the energy supply of the sensor has become one of the bottlenecks hindering the development and application of the sensor network.

In order to improve the battery life of sensors and further meet the needs of uninterrupted operation of sensors in the rapidly developing Internet of Things and wireless sensor networks, in addition to reducing the energy consumption of functional devices, the most fundamental method is to realize the energy self-supply of sensors. The energy self-supply of the sensor needs to realize its energy capture and storage. The concept of energy capture requires the sensor itself to easily collect the energy in the surrounding environment when it is working, and store it for supply when needed. Therefore, how to design a sensor that can effectively capture ambient energy and convert the ambient energy into usable electrical energy has become an urgent technical problem to be solved in the art. In addition, for the current sensors with self-powered characteristics, the energy harvesting and gas sensing units are separate devices, and the integration of energy harvesting and gas sensing units in the same device is also an urgent problem to be solved, which is important for the miniaturization and integration of self-powered sensors. ization is of great significance.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a self-powered sensor and a preparation method thereof. The self-powered sensor of the present invention uses a porous pyroelectric film material as both a sensitive unit and an energy acquisition unit, and realizes energy by capturing the thermal radiation of the surrounding environment. Self-supplied, on the basis of high integration, the process is simple and controllable, and the cost is low.

In order to achieve the above object, the present invention provides the following technical solutions:

Technical solution 1:

A self-powered gas sensor, characterized in that its structure is stacked sequentially from bottom to top: a porous substrate, a first silver nanowire film, a P-type porous conductive polymer, a porous pyroelectric film, and an N-type porous conductive polymer and the second silver nanowire film; the material of the porous pyroelectric film is polyvinylidene fluoride or vinylidene fluoride-trifluoroethylene copolymer.

Further, the material of the porous substrate in this technical solution is porous flexible indium tin oxide;

As a preferred embodiment, the thickness of the porous substrate in this technical solution is not greater than 0.5 mm;

As a preferred embodiment, the pore size of the porous substrate in this technical solution is not greater than 100 nanometers.

Further, in the technical solution, the material of the porous conductive polymer is preferably polythiophene and its derivatives.

In this technical solution, the silver nanowire thin film can be prepared by any suitable method such as self-assembly method, LB film method, spin coating method, etc. According to the embodiment of the present invention, the LB film method is preferably prepared, because the nanowires prepared by the LB film method are highly order and enhance the current collecting effect of nanowire films.

In this technical solution, the porous conductive polymer film is prepared by an in-situ deposition method; the specific operation is to deposit a polymerization solution of a mixed conductive polymer monomer and an oxidant on the surface of the silver nanowire film by spin coating, and obtain by controlling the volatilization rate of the solvent. Porous conductive polymer films.

In this technical solution, the porous pyroelectric film can be prepared by any suitable method such as spin coating and casting method. A large-area thin film can be obtained, and the process is simple.

Technical solution 2:

A method for preparing a self-powered gas sensor, which is characterized in that a silver nanowire film is prepared on a porous substrate; a porous conductive polymer film is prepared on the silver nanowire film; Porous conductive polymer film in the state of P-type doped state; preparation of porous pyroelectric film on the porous conductive polymer film of P-type doping state; then preparation of porous conductive polymer film on the porous pyroelectric film; using the method of electrical doping The N-type doped porous conductive polymer film is prepared; the silver nanowire thin film is prepared on the N-type doped porous conductive polymer film; finally, a self-powered gas sensor with a multi-layer film structure is prepared.

Further, the material of the porous substrate in this technical solution is porous flexible indium tin oxide;

As a preferred embodiment, the thickness of the porous substrate in this technical solution is not greater than 0.5 mm;

As a preferred embodiment, the pore size of the porous substrate in this technical solution is not greater than 100 nanometers.

Further, in the technical solution, the material of the porous conductive polymer is preferably polythiophene and its derivatives.

Further, in this technical solution, the silver nanowire thin film can be prepared by any suitable method such as self-assembly method, LB film method, spin coating method, etc; Current-collecting effect of nanowire films.

Further, in this technical solution, the porous conductive polymer film is prepared by an in-situ deposition method. The specific operation is to deposit a polymerization solution of a mixed conductive polymer monomer and an oxidant on the surface of the silver nanowire film by a spin coating method, and control the volatilization of the solvent. speed to obtain porous conductive polymer films.

Further, in this technical solution, the porous pyroelectric film can be prepared by any suitable method such as spin coating method and casting method. Porous structure, large-area thin films can be obtained, and the process is simple.

The innovation of the present invention is:

Different from the existing sensitive mechanism, the present invention utilizes the polarization process of the porous pyroelectric thin film material to reflect the sensor structure of its gas-sensing process. In the present invention, the porous pyroelectric thin film layer has two functions in the self-powered gas sensor; one is as the energy source of the device, because when the device captures external thermal radiation, the porous pyroelectric thin film material will generate heat to drive the device to work. Therefore, on the one hand, the porous pyroelectric film material is used as the solid electrolyte of the energy storage capacitor; on the other hand, it is the core of gas sensing, because the sensing signal output of the device is affected by the adsorbed molecules on the surface of the porous pyroelectric film. The conductive polymer electrode is used as the positive and negative electrodes of the energy storage capacitor in the self-powered gas sensor on the one hand, and the electrode of the gas sensing unit on the other hand. Therefore, the present invention highly integrates the energy storage unit and the sensitive unit, greatly reduces the manufacturing process of the device, and realizes the self-supply of energy of the gas sensor.

Compared with the prior art, the beneficial effects of the present invention are:

The self-powered gas sensor provided by the present invention has a reasonable structure design, adopts a porous pyroelectric film as an energy storage unit and a sensitive unit at the same time, can synergistically realize energy collection and generate gas-sensitive signals, so that the device structure is highly integrated; the preparation of different functional films is avoided. The problems of film-forming process mismatch, non-uniform film-forming and poor compatibility exist between the functional thin films; due to the generally low conductivity of the pyroelectric materials used, the carriers generated by the adsorption of gas molecules The change of concentration is small, especially in the detection process of low-concentration gas, the change of carrier concentration is even smaller, and the signal is usually annihilated by the background noise and it is difficult to detect the signal. The change of the carrier concentration is transformed into the change of the polarization characteristic of the material, and the charge generated by the change of the polarization characteristic can be effectively collected, thereby significantly enhancing the sensitivity of the gas sensing unit; in addition, the preparation process of the present invention is compared with the existing preparation process. , and has the advantage of compatibility with the preparation process of organic flexible electronic devices. Therefore, the device structure of the present invention has broad application prospects in flexible electronic devices.

Description of drawings

1 is a schematic structural diagram of a self-powered gas sensor provided by the present invention, wherein 1 is a porous substrate, 2 is a first silver nanowire film, 3 is a P-type porous conductive polymer, and 4 is a porous pyroelectric film. 5 is the P-type porous conductive polymer, and 6 is the second silver nanowire thin film.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and the following specific embodiments are merely illustrative, rather than restrictive.

Figure 1 is a schematic diagram of the structure of the self-powered gas sensor of the present invention, and its structure includes a stacked porous substrate 1, a first silver nanowire film 2, a P-type porous conductive polymer 3, a porous pyroelectric layer from bottom to top The film 4, the N-type porous conductive polymer 5 and the second silver nanowire film 6; the porous substrate 1 serves as the device support, the porous pyroelectric film 4 serves as the gas sensing unit and the energy collection unit, and the first silver nanowire film 2 As the current collector, the P-type porous conductive polymer acts as one electrode of the energy storage supercapacitor, and correspondingly, the second silver nanowire film 6 acts as another current current collector, and the P-type porous conductive polymer acts as the energy storage supercapacitor the other electrode; the porous pyroelectric film 4 captures the external thermal radiation to generate polarization, and the charges generated by the polarization are collected by the adjacent P-type conductive polymer 3 and N-type conductive polymer 5 on both sides and form the initial current of the device , therefore, the initial current of the sensor is provided by itself; when the gas to be measured is passed in, the gas molecules enter the porous pyroelectric film 4 along the porous structure of the structural layer, because the porous pyroelectric film 4 itself has gas-sensitive characteristics at this time, The polarization mode of the material changes, resulting in a change in the current of the energy storage device, thereby outputting a gas-sensing signal and realizing the identification of the gas to be measured. Example 1:

step 1:

Select a porous flexible indium tin oxide with a plane size of 5 × 5 mm, then clean it with a cleaning agent and then rinse it with running water for 5 to 10 times, and then place it in acetone, alcohol and deionized water for ultrasonic cleaning. Each ultrasonic cleaning uses low power Ultrasonic for 10 minutes, and finally use nitrogen to dry for later use;

Step 2:

Take a clean and dry sample bottle with a volume of 20 mL, use isopropanol as a solvent to prepare a silver nanowire solution with a concentration of 2 mg/mL, and ultrasonically disperse it for 4 hours to form a silver nanowire dispersion. Take 1 mL of the silver nanowire dispersion, The silver nanowires are uniformly deposited on one surface of the flexible porous indium tin oxide substrate by the LB film process;

Step 3:

Using n-butanol as a solvent to prepare a 3,4-ethylenedioxythiophene solution with a concentration of 1 mg/mL, and using n-butanol as a solvent to prepare a ferric toluene sulfonate solution with a concentration of 3 mg/mL; respectively, according to 3, The 4-ethylenedioxythiophene solution and the ferric toluenesulfonate solution are mixed in a volume ratio of 1:3 to obtain a mixed solution, which is allowed to stand for 3 hours to obtain a poly-3,4-ethylenedioxythiophene solution;

Step 4: Take 2 mL of poly-3,4-ethylenedioxythiophene solution and deposit it on the surface of the porous indium tin oxide substrate obtained in step 2 on which the silver nanowires are deposited by spin coating, and then place the substrate on the surface of the porous indium tin oxide substrate. Dry in an oven at 50 °C for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then place the porous substrate obtained in step 3 in an electrochemical cell for reaction, and the reaction solution is a 1M/L sodium sulfate solution. Under the condition of a voltage of 0.8V, poly-3,4-ethylenedioxythiophene was oxidized to P-type doping state, and then silver nanowires and P-type poly-3,4-ethylenedioxythiophene were prepared from bottom to top on the surface of the porous substrate. The complex structure formed by thiophene;

Step 5: Using nitrogen dimethylformamide as a solvent, weigh polyvinylidene fluoride to prepare a 1.5 mg/mL polyvinylidene fluoride solution, and ultrasonically disperse for 2 hours; then take 2 mL of polyvinylidene fluoride solution, It was deposited on the surface of the P-type poly-3,4-ethylenedioxythiophene obtained by the porous substrate treated in step 4 by the casting method, and the substrate was dried in an oven at 40°C for 1 hour to obtain polyvinylidene fluoride. film, and then obtain a composite structure formed by silver nanowires, P-type poly-3,4-ethylenedioxythiophene and polyvinylidene fluoride film from bottom to top on the surface of the porous substrate;

Step 6: Measure 2 mL of the poly-3,4-ethylenedioxythiophene solution obtained in step 3 again, deposit it on the surface of the polyvinylidene fluoride film of the porous substrate obtained in step 5 by spin coating, and then apply the Placed in a 50°C oven to dry for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then the substrate was placed in an electrochemical cell for reaction, and the reaction solution was a 1M/L sodium sulfate solution at a voltage of -0.8 Under the condition of V, the poly-3,4-ethylenedioxythiophene is oxidized to N-type doping state, and then silver nanowires, P-type poly-3,4-ethylenedioxythiophene, poly The composite structure formed by vinylidene fluoride film and N-type poly-3,4-ethylenedioxythiophene;

Step 7: Measure 1 mL of the silver nanowire dispersion liquid obtained in step 2 again, and uniformly deposit the silver nanowires on the surface of the N-type poly-3,4-ethylenedioxythiophene of the porous substrate obtained in step 6 by using the LB film process, and then Silver nanowires, P-type poly-3,4-ethylenedioxythiophene, polyvinylidene fluoride film, N-type poly-3,4-ethylenedioxythiophene and silver nanowires were prepared from bottom to top on the surface of the porous substrate to form a composite Structured self-powered gas sensor.

Example 2:

step 1:

Select a porous flexible indium tin oxide with a plane size of 5 × 5 mm, then clean it with a cleaning agent and then rinse it with running water for 5 to 10 times, and then place it in acetone, alcohol and deionized water for ultrasonic cleaning. Each ultrasonic cleaning uses low power Ultrasonic for 10 minutes, and finally use nitrogen to dry for later use;

Step 2:

Take a clean and dry sample bottle with a volume of 20 mL, use isopropanol as a solvent to prepare a silver nanowire solution with a concentration of 2 mg/mL, and ultrasonically disperse it for 4 hours to form a silver nanowire dispersion. Take 1 mL of the silver nanowire dispersion, The silver nanowires are uniformly deposited on one surface of the flexible porous indium tin oxide substrate by the LB film process;

Step 3:

Using n-butanol as a solvent to prepare a 3,4-ethylenedioxythiophene solution with a concentration of 1 mg/mL, and using n-butanol as a solvent to prepare a ferric toluene sulfonate solution with a concentration of 3 mg/mL; respectively, according to 3, The 4-ethylenedioxythiophene solution and the ferric toluenesulfonate solution are mixed in a volume ratio of 1:3 to obtain a mixed solution, which is allowed to stand for 3 hours to obtain a poly-3,4-ethylenedioxythiophene solution;

Step 4: Take 2 mL of poly-3,4-ethylenedioxythiophene solution and deposit it on the surface of the porous indium tin oxide substrate obtained in step 2 on which the silver nanowires are deposited by spin coating, and then place the substrate on the surface of the porous indium tin oxide substrate. Dry in an oven at 50 °C for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then place the porous substrate obtained in step 3 in an electrochemical cell for reaction, and the reaction solution is a 1M/L sodium sulfate solution. Under the condition of a voltage of 0.7V, poly-3,4-ethylenedioxythiophene was oxidized to P-type doping state, and then silver nanowires and P-type poly-3,4-ethylenedioxythiophene were prepared from bottom to top on the surface of the porous substrate. The complex structure formed by thiophene;

Step 5: Using nitrogen dimethylformamide as a solvent, weigh polyvinylidene fluoride to prepare a 1.5 mg/mL polyvinylidene fluoride solution, and ultrasonically disperse for 2 hours; then take 2 mL of polyvinylidene fluoride solution, It was deposited on the surface of the P-type poly-3,4-ethylenedioxythiophene obtained by the porous substrate treated in step 4 by the casting method, and the substrate was dried in an oven at 40°C for 1 hour to obtain polyvinylidene fluoride. film, and then obtain a composite structure formed by silver nanowires, P-type poly-3,4-ethylenedioxythiophene and polyvinylidene fluoride film from bottom to top on the surface of the porous substrate;

Step 6: Measure 2 mL of the poly-3,4-ethylenedioxythiophene solution obtained in step 3 again, deposit it on the surface of the polyvinylidene fluoride film of the porous substrate obtained in step 5 by spin coating, and then apply the Placed in a 50°C oven to dry for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then the substrate was placed in an electrochemical cell for reaction, and the reaction solution was a 1M/L sodium sulfate solution at a voltage of -0.7 Under the condition of V, the poly-3,4-ethylenedioxythiophene is oxidized to N-type doping state, and then silver nanowires, P-type poly-3,4-ethylenedioxythiophene, poly The composite structure formed by vinylidene fluoride film and N-type poly-3,4-ethylenedioxythiophene;

Step 7: Measure 1 mL of the silver nanowire dispersion liquid obtained in step 2 again, and uniformly deposit the silver nanowires on the surface of the N-type poly-3,4-ethylenedioxythiophene of the porous substrate obtained in step 6 by using the LB film process, and then Silver nanowires, P-type poly-3,4-ethylenedioxythiophene, polyvinylidene fluoride film, N-type poly-3,4-ethylenedioxythiophene and silver nanowires were prepared from bottom to top on the surface of the porous substrate to form a composite Structured self-powered gas sensor.

Example 3:

step 1:

Select a porous flexible indium tin oxide with a plane size of 5 × 5 mm, then clean it with a cleaning agent and then rinse it with running water for 5 to 10 times, and then place it in acetone, alcohol and deionized water for ultrasonic cleaning. Each ultrasonic cleaning uses low power Ultrasonic for 10 minutes, and finally use nitrogen to dry for later use;

Step 2:

Take a clean and dry sample bottle with a volume of 20 mL, use isopropanol as a solvent to prepare a silver nanowire solution with a concentration of 2 mg/mL, and ultrasonically disperse it for 4 hours to form a silver nanowire dispersion. Take 1 mL of the silver nanowire dispersion, The silver nanowires are uniformly deposited on one surface of the flexible porous indium tin oxide substrate by the LB film process;

Step 3:

Using n-butanol as a solvent to prepare a 3,4-ethylenedioxythiophene solution with a concentration of 1 mg/mL, and using n-butanol as a solvent to prepare a ferric toluene sulfonate solution with a concentration of 3 mg/mL; respectively, according to 3, The 4-ethylenedioxythiophene solution and the ferric toluenesulfonate solution are mixed in a volume ratio of 1:3 to obtain a mixed solution, which is allowed to stand for 3 hours to obtain a poly-3,4-ethylenedioxythiophene solution;

Step 4: Take 2 mL of poly-3,4-ethylenedioxythiophene solution and deposit it on the surface of the porous indium tin oxide substrate obtained in step 2 on which the silver nanowires are deposited by spin coating, and then place the substrate on the surface of the porous indium tin oxide substrate. Dry in an oven at 50 °C for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then place the porous substrate obtained in step 3 in an electrochemical cell for reaction, and the reaction solution is a 1M/L sodium sulfate solution. Under the condition of a voltage of 0.7V, poly-3,4-ethylenedioxythiophene was oxidized to P-type doping state, and then silver nanowires and P-type poly-3,4-ethylenedioxythiophene were prepared from bottom to top on the surface of the porous substrate. The complex structure formed by thiophene;

Step 5: Using nitrosodimethylformamide as a solvent, weigh polyvinylidene fluoride-trifluoroethylene to prepare a 1.5 mg/mL polyvinylidene fluoride-trifluoroethylene solution, and ultrasonically disperse for 2 hours; 2 mL of polyvinylidene fluoride solution was deposited on the surface of the P-type poly(3,4-ethylenedioxythiophene) porous substrate obtained by step 4 by the casting method, and the substrate was placed in a 40°C oven to dry for 1 After hours, a polyvinylidene fluoride-trifluoroethylene film was obtained, and then silver nanowires, P-type poly3,4-ethylenedioxythiophene and polyvinylidene fluoride-trifluoroethylene were prepared from bottom to top on the surface of the porous substrate. The composite structure formed by the film;

Step 6: Measure 2 mL of the poly-3,4-ethylenedioxythiophene solution obtained in step 3 again, deposit it on the polyvinylidene fluoride-trifluoroethylene surface of the porous substrate obtained in step 5 by spin coating, and then The substrate was dried in an oven at 50°C for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then the substrate was placed in an electrochemical cell for reaction, and the reaction solution was a 1M/L sodium sulfate solution. Under the condition of -0.7V, poly-3,4-ethylenedioxythiophene was oxidized to N-type doped state, and then silver nanowires, P-type poly-3,4-ethylenedioxythiophene were prepared from bottom to top on the surface of porous substrate. The composite structure formed by thiophene, polyvinylidene fluoride-trifluoroethylene film and N-type poly-3,4-ethylenedioxythiophene;

Step 7: Measure 1 mL of the silver nanowire dispersion liquid obtained in step 2 again, and uniformly deposit the silver nanowires on the surface of the N-type poly-3,4-ethylenedioxythiophene of the porous substrate obtained in step 6 by using the LB film process, and then Silver nanowires, P-type poly3,4-ethylenedioxythiophene, polyvinylidene fluoride-trifluoroethylene film, N-type poly3,4-ethylenedioxythiophene and silver were prepared from bottom to top on the surface of the porous substrate Self-powered gas sensors with nanowires forming composite structures.

Example 4:

step 1:

Select a porous flexible indium tin oxide with a plane size of 5 × 5 mm, then clean it with a cleaning agent and then rinse it with running water for 5 to 10 times, and then place it in acetone, alcohol and deionized water for ultrasonic cleaning. Each ultrasonic cleaning uses low power Ultrasonic for 10 minutes, and finally use nitrogen to dry for later use;

Step 2:

Take a clean and dry sample bottle with a volume of 20 mL, use isopropanol as a solvent to prepare a silver nanowire solution with a concentration of 2 mg/mL, and ultrasonically disperse it for 4 hours to form a silver nanowire dispersion. Take 1 mL of the silver nanowire dispersion, The silver nanowires are uniformly deposited on one surface of the flexible porous indium tin oxide substrate by the LB film process;

Step 3:

Using n-butanol as a solvent to prepare a 3,4-ethylenedioxythiophene solution with a concentration of 1 mg/mL, and using n-butanol as a solvent to prepare a ferric toluene sulfonate solution with a concentration of 3 mg/mL; respectively, according to 3, The 4-ethylenedioxythiophene solution and the ferric toluenesulfonate solution are mixed in a volume ratio of 1:3 to obtain a mixed solution, which is allowed to stand for 3 hours to obtain a poly-3,4-ethylenedioxythiophene solution;

Step 4: Take 2 mL of poly-3,4-ethylenedioxythiophene solution and deposit it on the surface of the porous indium tin oxide substrate obtained in step 2 on which the silver nanowires are deposited by spin coating, and then place the substrate on the surface of the porous indium tin oxide substrate. Dry in an oven at 50 °C for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then place the porous substrate obtained in step 3 in an electrochemical cell for reaction, and the reaction solution is a 1M/L sodium sulfate solution. Under the condition of a voltage of 0.8V, poly-3,4-ethylenedioxythiophene was oxidized to P-type doping state, and then silver nanowires and P-type poly-3,4-ethylenedioxythiophene were prepared from bottom to top on the surface of the porous substrate. The complex structure formed by thiophene;

Step 5: Using nitrosodimethylformamide as a solvent, weigh polyvinylidene fluoride-trifluoroethylene to prepare a 1.5 mg/mL polyvinylidene fluoride-trifluoroethylene solution, and ultrasonically disperse for 2 hours; 2 mL of polyvinylidene fluoride solution was deposited on the surface of the P-type poly(3,4-ethylenedioxythiophene) porous substrate obtained by step 4 by the casting method, and the substrate was placed in a 40°C oven to dry for 1 After hours, a polyvinylidene fluoride-trifluoroethylene film was obtained, and then silver nanowires, P-type poly3,4-ethylenedioxythiophene and polyvinylidene fluoride-trifluoroethylene were prepared from bottom to top on the surface of the porous substrate. The composite structure formed by the film;

Step 6: Measure 2 mL of the poly-3,4-ethylenedioxythiophene solution obtained in step 3 again, deposit it on the polyvinylidene fluoride-trifluoroethylene surface of the porous substrate obtained in step 5 by spin coating, and then The substrate was dried in an oven at 50°C for 1 hour to obtain a poly-3,4-ethylenedioxythiophene film; then the substrate was placed in an electrochemical cell for reaction, and the reaction solution was a 1M/L sodium sulfate solution. Under the condition of -0.8V, poly-3,4-ethylenedioxythiophene was oxidized to N-type doped state, and then silver nanowires and P-type poly-3,4-ethylenedioxythiophene were prepared from bottom to top on the surface of porous substrate. The composite structure formed by thiophene, polyvinylidene fluoride-trifluoroethylene film and N-type poly-3,4-ethylenedioxythiophene;

Step 7: Measure 1 mL of the silver nanowire dispersion liquid obtained in step 2 again, and uniformly deposit the silver nanowires on the surface of the N-type poly-3,4-ethylenedioxythiophene of the porous substrate obtained in step 6 by using the LB film process, and then Silver nanowires, P-type poly3,4-ethylenedioxythiophene, polyvinylidene fluoride-trifluoroethylene film, N-type poly3,4-ethylenedioxythiophene and silver were prepared from bottom to top on the surface of the porous substrate Self-powered gas sensors with nanowires forming composite structures.

Example 5:

step 1:

Select a porous flexible indium tin oxide with a plane size of 5 × 5 mm, then clean it with a cleaning agent and then rinse it with running water for 5 to 10 times, and then place it in acetone, alcohol and deionized water for ultrasonic cleaning. Each ultrasonic cleaning uses low power Ultrasonic for 10 minutes, and finally use nitrogen to dry for later use;

Step 2:

Take a clean and dry sample bottle with a volume of 20 mL, use isopropanol as a solvent to prepare a silver nanowire solution with a concentration of 2 mg/mL, and ultrasonically disperse it for 4 hours to form a silver nanowire dispersion. Take 1 mL of the silver nanowire dispersion, The silver nanowires are uniformly deposited on one surface of the flexible porous indium tin oxide substrate by the LB film process;

Step 3:

Using n-butanol as a solvent to prepare a chloromethylthiophene solution with a concentration of 1 mg/mL, and using n-butanol as a solvent to prepare a ferric chloride solution with a concentration of 3 mg/mL; The volume ratio of the iron compound solution is 2:5 and mixed to obtain a mixed solution, which is allowed to stand for 3 hours to obtain a polychloromethylthiophene solution;

Step 4: Take 2 mL of polychloromethylthiophene solution and deposit it on the surface of the porous indium tin oxide substrate obtained in step 2 on which silver nanowires are deposited by spin coating, and then place the substrate in a 50°C oven Dry for 1 hour to obtain a polychloromethylthiophene film; then place the porous substrate prepared in step 3 in an electrochemical cell for reaction, the reaction solution is a 1M/L sodium sulfate solution, and the voltage is 0.55V under the condition of making The polychloromethylthiophene is oxidized to a P-type doped state, and then a composite structure formed by silver nanowires and P-type polychloromethylthiophene is obtained on the surface of the porous substrate from bottom to top;

Step 5: Using nitrosodimethylformamide as a solvent, weigh polyvinylidene fluoride-trifluoroethylene to prepare a 1.5 mg/mL polyvinylidene fluoride-trifluoroethylene solution, and ultrasonically disperse for 2 hours; 2mL of polyvinylidene fluoride solution was deposited on the surface of the P-type polychloromethylthiophene obtained by the porous substrate processed in step 4 by the casting method, and the substrate was placed in a 40 ° C oven to dry for 1 hour to obtain a polyvinylidene fluoride. Vinylidene fluoride film, and then the composite structure formed by silver nanowires, P-type polychloromethyl thiophene and polyvinylidene fluoride-trifluoroethylene film is obtained from bottom to top on the surface of the porous substrate;

Step 6: Measure 2 mL of the polychloromethylthiophene solution obtained in step 3 again, deposit it on the surface of the polyvinylidene fluoride-trifluoroethylene film of the porous substrate obtained in step 5 by spin coating, and then apply the Placed in a 50°C oven to dry for 1 hour to obtain a polychloromethylthiophene film; then the substrate was placed in an electrochemical cell for reaction, and the reaction solution was a 1M/L sodium sulfate solution, under the condition of a voltage of -0.55V The polychloromethylthiophene is oxidized to an N-type doped state, and then silver nanowires, P-type polychloromethylthiophene, polyvinylidene fluoride-trifluoroethylene film and N-type nanowires are prepared from bottom to top on the surface of the porous substrate. The composite structure formed by polychloromethylthiophene;

Step 7: Measure 1 mL of the silver nanowire dispersion liquid obtained in step 2 again, and uniformly deposit the silver nanowires on the N-type polychloromethylthiophene surface of the porous substrate obtained in step 6 by using the LB film process, and then deposit the silver nanowires on the surface of the porous substrate obtained in step 6. A self-powered gas sensor with a composite structure is formed on the surface from bottom to top of silver nanowires, P-type polychloromethylthiophene, polyvinylidene fluoride-trifluoroethylene film, N-type polychloromethylthiophene and silver nanowires.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative rather than restrictive. Under the inspiration of the invention, many forms can be made without departing from the scope of the present invention and the protection scope of the claims, which all belong to the protection of the present invention.

Claims (10)

1. a self-powered gas sensor, is characterized in that, its structure is stacked sequentially from bottom to top and comprises: porous substrate, the first silver nanowire film, P-type porous conductive polymer, porous pyroelectric film, N-type porous Conductive polymer and second silver nanowire film; the material of the porous pyroelectric film is polyvinylidene fluoride or vinylidene fluoride-trifluoroethylene copolymer. 2 . The self-powered gas sensor according to claim 1 , wherein the porous substrate is made of porous flexible indium tin oxide. 3 . 3. A self-powered gas sensor according to claim 1, wherein the thickness of the porous substrate is not greater than 0.5 mm. 4 . The self-powered gas sensor according to claim 1 , wherein the pore size of the porous substrate is not greater than 100 nanometers. 5 . 5 . The self-powered gas sensor according to claim 1 , wherein the material of the porous conductive polymer is polythiophene or a derivative thereof. 6 . 6. A method for preparing a self-powered gas sensor, characterized in that a silver nanowire film is prepared on a porous substrate; a porous conductive polymer film is prepared on the silver nanowire film; Porous conductive polymer film in doped state; preparation of porous pyroelectric film on porous conductive polymer film in P-type doping state; preparation of porous conductive polymer film on porous pyroelectric film; electrical doping The method of preparing the N-type doped porous conductive polymer film; preparing the silver nanowire thin film on the N-type doped porous conductive polymer film; finally preparing a self-powered gas sensor with a multi-layer film structure. 7 . The method for preparing a self-powered gas sensor according to claim 6 , wherein the material of the porous substrate is porous flexible indium tin oxide. 8 . 8 . The method for preparing a self-powered gas sensor according to claim 6 , wherein the silver nanowire thin film is prepared by a self-assembly method, a LB film method or a spin coating method. 9 . 9 . The method for preparing a self-powered gas sensor according to claim 6 , wherein the porous conductive polymer film is prepared by an in-situ deposition method, and the material of the porous conductive polymer is polythiophene and its derivatives. 10 . 10 . The method for preparing a self-powered gas sensor according to claim 6 , wherein the porous pyroelectric film is prepared by a spin coating method or a casting method. 11 .