Chemical resistance type gas sensor based on organic semiconductor polymer film as well as preparation method and application of chemical resistance type gas sensor

Abstract

The invention relates to the technical field of gas sensing, in particular to a chemical resistance type gas sensor based on an organic semiconductor polymer film and a preparation method and application thereof, and the chemical resistance type gas sensor comprises a substrate, and a conversion element and a sensing element which are integrated on the substrate; the sensing element is an organic semiconductor polymer P3HT film; a P3HT solution is spin-coated on a substrate integrated with an interdigital electrode to form a P3HT thin film, then vacuum oxygen plasma treatment is performed by adopting a Hall ion source to modify the P3HT thin film, so that the chemical resistance type gas sensor for ammonia gas sensing is successfully constructed, the surface of the P3HT thin film subjected to oxygen plasma treatment has an oxygen-containing functional group, and the surface of the P3HT thin film subjected to oxygen plasma treatment has an oxygen-containing functional group. The P3HT thin film has excellent conductivity, when ammonia gas contacts with the surface of the P3HT thin film, the resistance change of the P3HT thin film can be detected by an instrument, then the sensitivity of the sensor is obtained, and compared with the prior art, the gas sensor is high in ammonia gas responsivity and has high-selectivity low detection limit.

Description

Technical Field

[0001] The present invention relates to the field of gas sensing technology, and in particular to a chemical resistance gas sensor based on an organic semiconductor polymer film, and a preparation method and application thereof. Background Art

[0002] Ammonia (NH3) is a colorless gas with a strong, pungent odor. It is highly soluble in water and exhibits certain chemical activity under specific conditions, such as high temperature and high pressure. It is widely used in many industries, including agriculture, chemical manufacturing, and refrigeration, but poses a risk of leakage. Leakage of NH3 poses multiple hazards to the human body. Even at relatively low concentrations, long-term exposure can cause persistent irritation and damage to the eyes and respiratory mucosa, leading to problems such as conjunctival and respiratory inflammation. Inhalation of high concentrations of NH3 can severely damage the respiratory system and even be life-threatening. Therefore, accurate measurement of NH3 concentrations is crucial for protecting the safety and health of workers in these industries. NH3 also has certain physiological effects in the body and can serve as a biomarker to reflect changes in certain physiological conditions. Real-time monitoring of NH3 concentrations in exhaled breath or body fluids can help detect early signs of certain diseases, allowing for timely intervention, and is therefore of great significance for human health monitoring.

[0003] Given the importance of detecting NH3 concentrations, various types of NH3 gas sensors have emerged, depending on their application areas and precision requirements. These include semiconductor metal oxide sensors, optical sensors, and biosensors. Chemiresistance sensors, with their significant advantages such as simple reaction mechanisms, low cost, and high sensitivity, have become a popular research topic. However, the abundance and diversity of sensitive materials for chemiresistance NH3 sensors presents several significant challenges. For example, metal oxide-based sensors generally require high operating temperatures and harsh working conditions, significantly limiting their application. Sensors made from organic carbon-based materials often suffer from poor sensitivity and stability. Therefore, developing a novel material with mild, high sensitivity, and excellent selectivity for use in NH3 sensors has become a critical issue in this field. This is crucial for further improving NH3 detection capabilities and serving agricultural production safety, industrial process monitoring, and human health monitoring.

[0004] Organic semiconductor polymer materials are highly flexible and can be processed in solution. They have good conductivity and abundant active sites. When interacting with NH3 gas molecules, the molecules of the organic semiconductor polymer material will undergo redox reactions with the lone pair electrons of NH3, causing the electrical signal of the material to change, thereby showing a good response. However, when organic semiconductor polymer materials are currently used to prepare sensors, the material is often transferred to the sensor surface by methods such as drop casting. However, this method has inherent limitations: first, it is difficult to accurately control the thickness of the film, resulting in the film being too thick or too thin; second, the material is easily unevenly distributed during the drop coating process, forming local accumulation or blank areas. The above defects significantly affect the consistency of sensor performance, making it difficult to guarantee the reproducibility of the test results, which limits the practical application and promotion of this technology. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a chemiresistive gas sensor based on an organic semiconductor polymer film, a preparation method and an application thereof. The P3HT film is modified by oxygen plasma treatment. The synthesized film is dense and uniform with controllable thickness. It can be directly used in a chemiresistive gas sensor without transfer and has high responsiveness and selectivity to NH3.

[0006] A chemiresistive gas sensor based on an organic semiconductor polymer film comprises a substrate and a conversion element and a sensing element integrated on the substrate; the sensing element is an organic semiconductor polymer P3HT film; the P3HT film is prepared by oxygen plasma and has a thickness of 10-50 nm; the substrate is ceramic.

[0007] Furthermore, the surface of the P3HT film is modified with oxygen-containing functional groups, and the content of the oxygen-containing functional groups is 5.02% to 8.65%, preferably 8.65%.

[0008] Furthermore, the conversion element is an interdigital electrode, the width of the interdigital electrode is 100 μm, and the channel width of the interdigital electrode is 50 μm; wherein, the interdigital electrode is a gold electrode.

[0009] The present invention also provides a method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film, which includes cleaning a substrate and preparing a sensor. The preparation of the sensor includes a P3HT film forming process and a P3HT film modification process. The P3HT film modification process is a process of vacuum oxygen plasma treatment using a Hall ion source. The vacuum degree is 1×10 -2 ~4×10 -2 Pa.

[0010] Furthermore, the oxygen flow rate of the vacuum oxygen plasma treatment is 3 to 5 sccm, and the treatment time is 5 to 60 s.

[0011] Preferably, the vacuum oxygen plasma treatment time is 15 s.

[0012] Furthermore, the cathode voltage of the vacuum oxygen plasma treatment is 10-15V, the cathode current is 8.0-10.0A; the anode voltage is 120-150V, and the anode current is 1.0-1.9A.

[0013] Furthermore, the P3HT film is formed by spin coating a P3HT solution on a substrate integrated with interdigitated electrodes and performing an annealing treatment; the spin coating speed is 1500 rpm; the annealing temperature is 170° C., and the annealing time is 10 min;

[0014] The temperature before spin coating is controlled at 20-30° C., and the humidity is controlled at 35% RH.

[0015] Furthermore, the P3HT solution is obtained by mixing and stirring an organic semiconductor polymer P3HT powder and chlorobenzene; wherein the stirring temperature is 90° C., the stirring speed is 400 r / min, and the stirring time is 6-12 h.

[0016] Furthermore, the substrate cleaning includes ultrasonic cleaning → water bath heating cleaning → cleaning agent removal → isopropyl alcohol cleaning process; the cleaning liquid used in the ultrasonic cleaning process is ultrapure water, and the cleaning time is 10 to 20 minutes; the cleaning liquid used in the water bath heating cleaning process is piranha solution, the cleaning temperature is 100°C, and the cleaning time is 15 to 30 minutes; the cleaning agent removal process is to use ultrapure water to rinse the residual piranha solution, and the number of rinses is ≥3 times; the isopropyl alcohol cleaning process is ultrasonic cleaning, and the cleaning time is 5 to 15 minutes;

[0017] The piranha solution is a mixed solution of concentrated sulfuric acid and hydrogen peroxide in a volume ratio of 7:3.

[0018] The present invention also provides the use of the above-mentioned chemiresistive gas sensor based on the organic semiconductor polymer film in NH3 detection, or the use of the chemiresistive gas sensor based on the organic semiconductor polymer film prepared by the above-mentioned preparation method in NH3 detection.

[0019] The advantages of the present invention are:

[0020] 1. The present invention prepares an organic semiconductor polymer P3HT thin film by spin coating, which can effectively control the film thickness and uniformity. The surface of the P3HT film is modified by vacuum oxygen plasma treatment using a Hall ion source, which can effectively introduce oxygen-containing functional groups on the surface of the P3HT. These functional groups serve as active sites to enhance the interaction between P3HT and NH3, thereby improving the sensitivity and selectivity of the sensor. At the same time, the plasma treatment can regulate the microstructure of the P3HT film and significantly increase the specific surface area of the sensing electrode, so that the sensor has rapid response and high sensitivity to NH3. It has a wide range of applications and can be used as a sensing material for various NH3 sensors.

[0021] 2. The chemical resistance type gas sensor prepared based on the P3HT film of the present invention has good bonding with the substrate, and has the characteristics of rapid response and high sensitivity when used for NH3 detection. Compared with the gas sensor obtained by the traditional preparation method, it has a lower detection limit, and the preparation method is controllable, simple to operate, and highly repeatable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a chemical resistance type gas sensor based on an organic semiconductor polymer P3HT film in the present invention;

[0023] Figure 2 It is a schematic diagram of the molecular structure of the organic semiconductor polymer P3HT;

[0024] Figure 3 This is a schematic diagram of the preparation process of the chemical resistance type gas sensor of P3HT film;

[0025] Figure 4 It is a schematic diagram of the oxygen plasma treatment process and principle;

[0026] Figure 5 is the UV-visible absorption spectrum of P3HT film under different plasma treatment times;

[0027] Figure 6 This is the front view of the P3HT film surface obtained by atomic force microscopy when the oxygen plasma treatment time is 15 s;

[0028] Figure 7 2. The XPS test results of P3HT films at different oxygen plasma treatment times (a-e in the figure are X-ray photoelectron spectra of P3HT films at different oxygen plasma treatment times, and f is the percentage result of CC, CS and C=O functional groups in the X-ray photoelectron spectra analysis);

[0029] Figure 8The electrical performance test results of P3HT thin films are shown in Figure 1 (a is the IV curve of P3HT at different base temperatures; b is the conductivity curve of P3HT at different base temperatures);

[0030] Figure 9 The P3HT thin film gas sensor treated with oxygen plasma for 15 seconds responds to 10-50ppm gas in real time.

[0031] Figure 10 This is the response recovery curve of the P3HT thin film gas sensor treated with oxygen plasma for 15 seconds to 18ppm NH3;

[0032] Figure 11 This is the interference test of P3HT thin film gas sensor treated with oxygen plasma for 15s;

[0033] Figure 12 It is the chemical reaction formula of the sensing reaction between the P3HT film and the NH3 molecule when the sensor of the present invention is working;

[0034] Reference numerals:

[0035] 1. Ceramic substrate; 2. Sensing element; 3. Conversion element. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] It should be noted that the various installation methods and technical terms mentioned in the present invention are technical terms that have long been clearly known in the relevant technical field and therefore will not be further explained. In addition, the same reference numerals are used for the same components, but this does not affect nor constitute an accurate understanding of the technical solution by those skilled in the art.

[0038] Example 1

[0039] The present invention provides a chemical resistance type gas sensor based on an organic semiconductor polymer film, the structure of which is as follows: Figure 1 As shown, it includes a ceramic substrate 1, an organic semiconductor polymer P3HT film as a sensing element 2 and an interdigitated electrode as a conversion element 3. The sensing element 2 and the conversion element 3 are integrated on the ceramic substrate. The molecular structure of the organic semiconductor polymer P3HT is as shown in FIG. Figure 2The P3HT film is prepared using oxygen plasma and has a thickness of 10-50 nm. The surface of the P3HT film is modified with oxygen-containing functional groups, with the content of oxygen-containing functional groups ranging from 5.02% to 8.65%. The interdigitated electrodes are gold electrodes with a width of 100 μm and a channel width of 50 μm.

[0040] The specific preparation steps of the sensor are as follows:

[0041] Step 1: Cleaning the substrate

[0042] First, ultrasonic cleaning was performed: the substrate with the interdigitated electrodes was placed on a cleaning basket, placed in a beaker, and cleaned with pure water in an ultrasonic cleaner with a power of 40 W for 10 minutes;

[0043] Then, the substrate was heated and cleaned in a water bath: the substrate was cleaned with piranha solution by boiling at 100°C for 10 minutes to remove dust on the substrate surface (the piranha solution in this embodiment was prepared from 70 mL of concentrated sulfuric acid and 30 mL of hydrogen peroxide);

[0044] Then remove the cleaning agent: clean the residual piranha solution on the substrate surface with pure water for a total of 3 times, each time for 5 minutes;

[0045] Finally, perform isopropyl alcohol cleaning: perform the final cleaning with isopropyl alcohol ultrasonic cleaning for 10 minutes. After the cleaning is completed, the clean substrate is obtained and quickly blown dry with a nitrogen gun for later use;

[0046] Step 2: Preparation of sensor

[0047] (1) Synthesis of P3HT solution

[0048] Weigh 25 mg of P3HT powder into a 10 mL sample bottle, slowly add 5 mL of chlorobenzene solution to completely dissolve the P3HT powder, then transfer to a thermostatic stirring table and heat and stir at 90°C and 400 rpm for 12 h to mix until the mixture is uniform to obtain a P3HT solution;

[0049] (2) Formation of P3HT thin film

[0050] First, control the temperature to 25°C (between 20 and 30°C) and the humidity to 35% RH;

[0051] Then, 50 μL of the P3HT solution obtained in step (1) was taken with a pipette and evenly drop-casted on the clean substrate obtained in step 1 (specifically, on the surface of the interdigital electrode integrated on the clean substrate), and spin-coated at a speed of 1500 rpm using a spin coater. After spin coating, the film was placed on a hot plate and annealed at 170° C. for 10 minutes to remove the residual solvent, thereby obtaining a P3HT film. Figure 3 As shown;

[0052] (3) Modification of P3HT films

[0053] like Figure 4 As shown, a Hall ion source is used to introduce oxygen for vacuum oxygen plasma treatment:

[0054] The P3HT film obtained in step (2) was placed in the geometric center of the glass base in the vacuum chamber, and the air pump and molecular pump were turned on to evacuate the chamber until the vacuum degree reached 4×10 -3 Pa, 3-5 sccm of oxygen is introduced into the vacuum chamber to maintain the vacuum degree at 1×10 -2 ~4×10 -2 Pa, turn on the Hall ion source, adjust the anode voltage between 120 and 150 V, adjust the anode current between 1.0 and 1.9 A, start timing, and record the cathode voltage (8.0 to 10.0 A) and current (10 to 15 V); when the treatment time reaches 15 s, turn off the ion source, introduce argon gas to break the vacuum state, the chamber door automatically opens, and the sample is taken out. The vacuum oxygen plasma treatment is completed to obtain the chemical resistance gas sensor based on the organic semiconductor polymer film.

[0055] Example 2

[0056] The preparation process of this embodiment is the same as that of Example 1, except that the preparation parameter conditions are different: the vacuum oxygen plasma treatment time of this embodiment is 10 seconds.

[0057] Example 3

[0058] The preparation process of this embodiment is the same as that of Example 1, except that the preparation parameter conditions are different: the vacuum oxygen plasma treatment time of this embodiment is 30 seconds.

[0059] Example 4

[0060] The preparation process of this embodiment is the same as that of Example 1, except that the preparation parameter conditions are different: the vacuum oxygen plasma treatment time of this embodiment is 60 seconds.

[0061] Comparative Example 1

[0062] The preparation process of this comparative example is the same as that of Example 1, except that the P3HT film of this comparative example is not modified, and the process of performing vacuum oxygen plasma treatment using a Hall ion source in step 3 is not performed.

[0063] Test Example 1

[0064] This test example characterizes the optical properties of P3HT prepared in Examples 1-4 and Comparative Example 1 based on the light absorption theory to analyze the chemical composition and structure of the film surface. The results are as follows: Figure 5As shown, analysis of the surface modification of Examples 1-4 and Comparative Example 1 reveals that the surface structure of the P3HT films of the Examples treated with oxygen plasma changes compared to the P3HT films of the Comparative Example that were not treated with oxygen plasma. The formation of a thin layer modified with oxygen-containing functional groups on the surface of the P3HT films alters the electron cloud distribution and chemical bonding characteristics of the film surface, thereby relatively changing the film's ability to absorb ultraviolet light. This indicates that the film's ultraviolet light absorption properties are closely related to its surface chemical structure and composition. Excessive ultraviolet light absorption can absorb other stray light, generating additional electrical signal interference and reducing the accuracy of the detection results. Excessive absorption can weaken the electrical signal and reduce detection sensitivity. Therefore, the film obtained in Example 1, treated with a plasma treatment time of 15 seconds, exhibits moderate ultraviolet light absorption, making it the optimal embodiment of the present invention.

[0065] The principle of introducing functional groups is:

[0066] From the perspective of structural changes, during oxygen plasma treatment, highly reactive oxygen ions and free radicals react with the C-H bonds in the P3HT molecular chain, introducing oxygen-containing functional groups. The introduction of these functional groups disrupts the original chemical equilibrium of the P3HT molecular chain, altering its electronic structure and spatial configuration, significantly changing the chemical properties of the molecular chain. Furthermore, the newly introduced oxygen-containing functional groups act as active sites, enhancing the interaction between the molecular chain and other substances and improving its affinity for other substances.

[0067] Test Example 2

[0068] In this test example, the surface morphology of the P3HT films of Examples 1-4 and Comparative Example 1 was analyzed using an atomic force microscope, and the root mean square roughness (Rq) was tested. The results are shown in Table 1. From the results in Table 1, it can be seen that the surface of the P3HT film prepared by the embodiment method is dense and continuous, and the uniformity is good. Among them, the Rq measured when the vacuum oxygen plasma treatment time of Example 1 is 15s is 3.13nm, the Rq measured when the vacuum oxygen plasma treatment time of Example 2 is 10s is 6.95nm, the Rq measured when the vacuum oxygen plasma treatment time of Example 3 is 30s is 1.97nm, and the Rq measured when the vacuum oxygen plasma treatment time of Example 4 is 30s is 1.31nm. In contrast, the surface uniformity of the P3HT film obtained by the method of Comparative Example 1 (when the vacuum oxygen plasma treatment time is 0 s) is poor, and the measured root mean square roughness (Rq) is 8.34 nm. It can be seen that the longer the vacuum oxygen plasma treatment time, the smaller the measured root mean square roughness, and the more uniform the film surface. Figure 6 This is the front view of the atomic force microscope when the processing time is 15s.

[0069] Test Example 3

[0070] This test example uses XPS spectroscopy to analyze the content of oxygen-containing functional groups on the surface of P3HT films. An in-depth and detailed analysis of the oxygen elements on the surface of P3HT films obtained by plasma treatment for different durations in Examples 1-4 and Comparative Example 1 was conducted. Through precise detection, the O1s peak was successfully identified. From the specific data level, it can be seen that as the plasma treatment time gradually increases, the O1s content shows a regular change trend. The results are as follows: Figure 7 As shown. Figure 7 a It can be seen from comparative example 1 that when the P3HT film is not treated with oxygen plasma (corresponding to the vacuum oxygen plasma treatment time of 0s), the O1s content is only 0.77%; Figure 7 b shows that when the treatment time of Example 2 reaches 10s, the content climbs to 8.05%; compared with Comparative Example 1, when the treatment time of Example 1 of the present invention is extended to 15s, the O1s content further increases to 8.65%, reaching a peak state ( Figure 7 c); When the treatment time of Example 3 was 30s, the O1s content began to decrease slightly, down to 8.44% ( Figure 7 d); When the treatment time of Example 4 reaches 60s, the O1s content is reduced to 5.02% ( Figure 7 e) At the same time, the percentage of CC, CS and C=O functional groups can be obtained from the X-ray photoelectron spectroscopy analysis, such as Figure 7 As shown in f.

[0071] Table 1 Performance parameters of P3HT films under different vacuum oxygen plasma treatment times

[0072]

[0073] It can be seen from Test Examples 1 to 3 that the sensor prepared according to the method of Example 1 (vacuum oxygen plasma treatment time 15s) has the highest content of surface-modified oxygen-containing functional groups, which makes the film have the best ability to absorb ultraviolet light, and the surface is more uniform and smooth, which is the optimal embodiment of this application.

[0074] Test Example 4

[0075] This test example uses the two-probe method to test the electrical properties of the film, and explores the optimal electrical properties of the P3HT film prepared by the method of the best embodiment 1 at different temperatures, such as Figure 8 As shown, the details are as follows:

[0076] The IV curves of P3HT films at 30℃, 50℃, 70℃, 90℃, 110℃ and 120℃ were tested respectively. The test results are as follows: Figure 8As shown in a, the conductivity formula is used to further calculate the conductivity of the film at each temperature, and the relevant results are shown in Figure 8 b. The conductivity calculation formula is as follows: Where δ is the conductivity of the film, L is the distance between the two electrodes, R is the measured resistance, and S is the cross-sectional area of the film.

[0077] Depend on Figure 7 The test results show that at 90°C, the resistance of the P3HT film reaches its minimum value and its conductivity reaches its maximum value. This shows that the optimal operating temperature of the P3HT film is the temperature at which the P3HT film can maintain good conductivity in subsequent experiments.

[0078] Test Example 5

[0079] This test example uses a gas-sensitive test system to test the performance of the sensors prepared by the methods of the best examples 1-4 and comparative example 1. The gas-sensitive performance of the P3HT film to different concentrations of NH3 at five different treatment times in the examples and comparative examples is tested, which are 10ppm, 12.5ppm, 18ppm, 25ppm, 35ppm, and 50ppm, respectively. Figure 9 As shown in the figure, the results show that when the treatment time is 15s, the calculated P3HT film has the highest response to NH3 and the lowest detection limit is 10ppm;

[0080] The calculation formula for the detection limit is: Where σ represents noise and k represents sensitivity.

[0081] Test Example 6

[0082] This test example tests the response recovery of the P3HT thin film chemiresistive gas sensor of Example 1 and Comparative Example 1. The results show that compared with the P3HT thin film sensor of Comparative Example 1 that was not treated with oxygen plasma, the P3HT thin film sensor of Example 1 treated with 15s plasma in the gas concentration of 18ppm has a response time of only 60s after treatment, which is much shorter than the 370s of the untreated sensor. The recovery time of 123s is also shorter than the 270s of the untreated sensor. The results of Example 1 are shown as follows: Figure 10 This shows that the sensor obtained by oxygen plasma treatment (Plasma treatment) for 15 seconds in Example 1 significantly improved the response and recovery speed of the gas, and optimized its sensing performance.

[0083] Test Example 7

[0084] The selectivity of NH3 of the P3HT thin film gas sensor treated with plasma for 15s in Example 1 was tested for 100ppm of carbon dioxide, carbon monoxide, methane, formaldehyde, ethanol, methanol and acetone. The results are as follows: Figure 11 As shown, the sensor resistance changes very little, demonstrating that the P3HT thin film gas sensor treated for 15 seconds has specific recognition capabilities for NH3 under complex conditions. Table 1 summarizes the responses to 100 ppm interfering substances. It can be seen that the P3HT thin film gas sensor treated for 15 seconds responds much better to 18 ppm NH3 than to other 100 ppm interfering substances. The responsivity of the P3HT thin film sensor to interfering gases and NH3 is shown in Table 2.

[0085] The sensing mechanism of the gas sensor based on the organic semiconductor compound thin film (P3HT film) of the present invention is:

[0086] like Figure 12 As shown, during the gas sensing process, NH3 can interact with P3HT by virtue of the unique lone pair electrons in its molecular structure. NH3 molecules gradually penetrate into the interface of the P3HT film, where they capture hole charges, thereby reducing the carrier density and conductivity. Macroscopically, this is manifested as a decrease in current and an increase in resistance, thereby achieving a sensing response to NH3. Since the modification of oxygen-containing functional groups is beneficial to gas mass transfer, the present invention has a lower detection limit.

[0087] Table 2 Responsivity of P3HT thin film sensor to interfering gases and NH3 gas

[0088] Gas type Concentration (ppm) Responsiveness (%) <![CDATA[CO2]]> 100 0.43 <![CDATA[NH3]]> 18 47.61 CO 100 0.21 <![CDATA[CH4]]> 100 0.34 HCHO 100 0.12 <![CDATA[C2H5OH]]> 100 0.09 <![CDATA[CH3OH]]> 100 0.15 <![CDATA[CH3COCH3]]> 100 0.63

[0089] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention may be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description. It is intended that all variations that fall within the meaning and range of equivalents of the claims be embraced within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent replacements, and improvements made to the above embodiments based on the technical essence of the present invention shall be included in the scope of protection of the technical solution of the present invention.

Claims

1. A chemical resistance gas sensor based on an organic semiconductor polymer film, characterized in that: The invention comprises a substrate and a conversion element and a sensing element integrated on the substrate; the sensing element is an organic semiconductor polymer P3HT film; the P3HT film is prepared by oxygen plasma and has a thickness of 10-50nm; the substrate is ceramic.

2. The chemical resistance type gas sensor based on organic semiconductor polymer film according to claim 1, characterized in that: The surface of the P3HT film is modified with oxygen-containing functional groups, and the content of the oxygen-containing functional groups is 5.02% to 8.65%.

3. The chemical resistance type gas sensor based on organic semiconductor polymer film according to claim 1, characterized in that: The conversion element is an interdigital electrode, the width of the interdigital electrode is 100 μm, and the channel width of the interdigital electrode is 50 μm; wherein the interdigital electrode is a gold electrode.

4. A method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film according to claim 1, comprising cleaning a substrate and preparing a sensor, characterized in that: The preparation of the sensor includes a P3HT film formation process and a P3HT film modification process; the P3HT film modification process is a process of vacuum oxygen plasma treatment using a Hall ion source; wherein the vacuum degree is 1×10 -2 ~4×10 -2 Pa.

5. The method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film according to claim 4, characterized in that: The oxygen flow rate of the vacuum oxygen plasma treatment is 3 to 5 sccm, and the treatment time is 5 to 60 seconds.

6. The method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film according to claim 5, characterized in that: The cathode voltage of the vacuum oxygen plasma treatment is 10-15V, the cathode current is 8.0-10.0A; the anode voltage is 120-150V, and the anode current is 1.0-1.9A.

7. The method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film according to claim 4, characterized in that: The P3HT film is formed by spin coating a P3HT solution on a substrate integrated with interdigitated electrodes and performing an annealing treatment; the spin coating speed is 1500 rpm; the annealing temperature is 170° C., and the annealing time is 10 minutes; The temperature before spin coating is controlled at 20-30° C., and the humidity is controlled at 35% RH.

8. The method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film according to claim 7, characterized in that: The P3HT solution is obtained by mixing and stirring an organic semiconductor polymer P3HT powder and chlorobenzene; wherein the stirring temperature is 90° C., the stirring speed is 400 r / min, and the stirring time is 6-12 hours.

9. The method for preparing a chemical resistance type gas sensor based on an organic semiconductor polymer film according to claim 4, characterized in that: The substrate cleaning process includes ultrasonic cleaning → water bath heating cleaning → cleaning agent removal → isopropyl alcohol cleaning. The cleaning liquid used in the ultrasonic cleaning process is ultrapure water, and the cleaning time is 10 to 20 minutes. The cleaning liquid used in the water bath heating cleaning process is piranha solution, the cleaning temperature is 100°C, and the cleaning time is 15 to 30 minutes. The cleaning agent removal process is to rinse the residual piranha solution with ultrapure water, and the number of rinses is ≥3 times. The isopropyl alcohol cleaning process is ultrasonic cleaning, and the cleaning time is 5 to 15 minutes. The piranha solution is a mixed solution of concentrated sulfuric acid and hydrogen peroxide in a volume ratio of 7:

3.

10. Use of a chemiresistive gas sensor based on an organic semiconductor polymer film according to any one of claims 1 to 3 or a chemiresistive gas sensor based on an organic semiconductor polymer film prepared by the preparation method according to any one of claims 4 to 9 in NH3 detection.

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