Application of a charge-transfer coated semiconductor material in gas-sensitive sensors

Abstract

This application discloses the application of a charge-transfer coated semiconductor material in a gas-sensitive sensor, belonging to the field of semiconductor sensor material technology. The application includes contacting the charge-transfer coated semiconductor material with the gas to be detected; the charge-transfer coated semiconductor material is a gas-sensitive material formed by coating an organic component onto the outer surface of an initial semiconductor through charge transfer. This application utilizes the presence of charge transfer interactions to improve the carrier mobility and charge-separated state lifetime of the semiconductor, thereby improving gas detection sensitivity and reducing operating temperature. Furthermore, it utilizes the redox properties of the organic coating component outside the semiconductor to improve gas selectivity. This application retains the basic properties of the initial semiconductor while reducing application costs through simplified material preparation, making it universally applicable.

Description

Technical Field

[0001] This application relates to the application of a charge-transfer coated semiconductor material in a gas-sensitive sensor device, belonging to the field of semiconductor sensor material technology. Background Technology

[0002] Gas sensors can identify and sense the presence and concentration of specific gases in the working environment, and are widely used in environmental, public safety, and food detection fields. Chemi-resistive gas sensors are sensors that convert the composition and concentration of detected gases into electrical signals. They are characterized by simple manufacturing processes, low cost, easy integration, and miniaturization, and currently dominate the market. Gas-sensitive materials are key components of chemi-resistive gas sensors, but currently suffer from several shortcomings: First, they have low room temperature sensitivity and high operating temperature, meaning they are insensitive or unresponsive at room temperature, typically requiring operating temperatures above 200°C. This necessitates fixed sockets for the gas sensors, hindering on-demand placement or shortening battery life and causing maintenance difficulties. Second, they have poor selectivity, easily affected by gases other than those being measured in the working environment, leading to false alarms or failure to detect. Existing technologies for optimizing semiconductor gas-sensitive materials mainly include nano-sizing, doping, heterojunction construction, composite formation, and heat treatment. These methods aim to improve the gas-sensing performance of the materials, such as sensitivity, selectivity, and stability, by altering their structure, composition, or surface properties. However, these methods also have certain drawbacks: Nanotechnology can significantly increase the specific surface area of ​​materials and increase gas adsorption sites, but the aggregation of nanoparticles may affect gas diffusion and adsorption, and the high surface energy of nanomaterials makes them prone to reacting with gases in the environment, leading to decreased stability; Doping technology changes the band structure and electron distribution of materials by introducing other elements, but excessive doping may lead to excessive conductivity, which may reduce gas-sensing performance, and the introduction of dopants may introduce new impurity phases, affecting the purity and stability of the material; Heterojunction technology constructs heterojunctions between semiconductors, semiconductors and metals, or semiconductors and carbon materials (such as graphene, carbon nanotubes, etc.). Charge transfer and band bending at the heterojunction interface affect the conductivity of the gas-sensing material, thereby improving its gas-sensing performance, but this technology is complex to prepare and costly; Composite technology improves gas-sensing performance by combining the advantages of multiple materials, but the preparation process of composite materials is complex, requiring precise control of the proportion and distribution of each component, and the interaction between components may lead to performance instability; Heat treatment technology improves performance by improving the crystal structure and surface properties of materials, but high-temperature treatment may cause phase transitions or decomposition of materials, affecting stability and performance.

[0003] Therefore, it is crucial to develop a simple and universal method to improve the sensitivity and selectivity of chemimetric resistance gas sensors and reduce their operating temperature. Summary of the Invention

[0004] To address the problems of low sensitivity, poor selectivity, and high operating temperature in existing chemical resistance gas sensors, as well as the difficulty in simultaneously achieving various gas sensing performance characteristics (stability, high sensitivity, fast response and recovery, room temperature detection, and good selectivity), this application provides an application of charge transfer coated semiconductor materials in gas sensor devices. By using charge transfer coated semiconductor materials as gas sensing materials in gas sensor devices, the presence of charge transfer interactions improves the carrier mobility and charge separation state lifetime of the semiconductor, thereby improving gas detection sensitivity, reducing operating temperature, and utilizing the redox properties of the organic coating components outside the semiconductor to improve gas selectivity.

[0005] The technical solution adopted in this application is as follows:

[0006] The application of a charge-transfer coated semiconductor material in a gas-sensitive sensor includes: contacting the charge-transfer coated semiconductor material with the gas to be measured;

[0007] The charge-transfer coated semiconductor material is:

[0008] Gas-sensitive materials are formed by coating organic components onto the outer surface of an initial semiconductor through charge transfer.

[0009] Optionally, the operating temperature of the gas-sensitive sensor is 0–200°C.

[0010] Optionally, the gas to be tested is an oxidizing gas and / or a reducing gas.

[0011] Optionally, the gas to be tested is selected from at least one of hydrogen sulfide, nitrogen dioxide, carbon monoxide, ammonia, sulfur dioxide, nitric oxide, and methane.

[0012] Optionally, the morphology of the initial semiconductor is selected from at least one of micron or nanostructures, thin films, and bulk materials.

[0013] Optionally, the micron or nanostructure is selected from at least one of sheet-like, rod-like, spherical, or array structures of nano or micron size.

[0014] Optionally, the initial semiconductor is preferably in the form of a thin film.

[0015] Compared to bulk semiconductors, thin-film semiconductor materials have a higher specific surface area and more sites that can form charge transfer complexes with organic coating components, thereby improving the gas-sensing performance of semiconductor materials.

[0016] Optionally, the initial semiconductor is selected from at least one of elemental semiconductors, metal compound semiconductors, and organic compound semiconductors.

[0017] Optionally, the elemental semiconductor is selected from at least one of silicon (Si), germanium (Ge), phosphorus (P), selenium (Se), antimony (Sb), and boron (B).

[0018] Optionally, the metal compound semiconductor is selected from at least one of metal oxides, sulfides, selenides, tellurides, phosphides, carbides, nitrides, and halides.

[0019] Optionally, the metal oxide is selected from at least one of ZnO, TiO2, SnO2, WO3, Fe2O3, In2O3, CuO, Co3O4, Cr2O3, NiO, Mn3O4, and ZrO2.

[0020] Optionally, the sulfide is selected from at least one of ZnS, CdS, MoS2, and WS2.

[0021] Optionally, the organic compound semiconductor is selected from semiconductors such as coordination polymers, covalent organic frameworks (COF), hydrogen-bonded organic frameworks (HOF), and conductive polymers.

[0022] Optionally, the coordination polymer is selected from at least one of MOF-5, MOF-177, MOF-210, MOF-303, IRMOF series, UIO series, MIL series, and HTTP series.

[0023] Optionally, the covalent organic framework (COF) is selected from at least one of boron-containing COF materials, imine-based COF materials, triazine-based COF materials, epoxy-based COF materials, and anhydride-based COF materials.

[0024] Preferably, the initial semiconductor is selected from at least one of TiO2, SnO2, UIO-66 semiconductor, and Cu-HTTP semiconductor.

[0025] Preferably, the morphology of the initial semiconductor is selected from thin film or powder.

[0026] Optionally, the organic component is selected from electron-donating organic components and / or electron-gaining organic components.

[0027] Optionally, the electron-donating organic component is selected from at least one of polythiophene (P3HT), polyphenylenevinyl chloride (PPV) and its derivatives, polyaniline (PANI), polyfluorene (PF) and its derivatives, organic fullerene derivatives, polypyrrole, and poly(p-phenylenevinyl chloride).

[0028] Optionally, the electron-giving organic component is selected from at least one of fullerene (C60), perylene tetraimide (NDI), perylene tetraimide (PDI), isoindigo (IC), methyl isoindigo (MeIC), viologen and its derivatives, 7,7,8,8-tetracyanoquinone dimethyl ether (TCNQ) and its derivatives, polythiadiazole, poly(p-phenylene oxide), poly(PTAA) and its derivatives.

[0029] The organic components mentioned above are molecules that readily form charge-transfer complexes.

[0030] Preferably, the organic component is selected from at least one of mono-terminated methyl viologen, di-terminated phenyl viologen, and 7,7,8,8-tetracyanoquinone dimethyl ether (TCNQ).

[0031] Optionally, the charge-transfer coated semiconductor material is prepared by a method comprising the following steps:

[0032] S1. Mix the materials containing the organic components and solvent to obtain a coating solution;

[0033] S2. The initial semiconductor is immersed in a coating solution and stirred, or the initial semiconductor is mixed with a coating solution and dispersed to form a coating layer. Then, it is washed and dried to obtain a charge transfer coated semiconductor material.

[0034] Optionally, the solvent is selected from at least one of water, ethanol, methanol, acetone, ethylene glycol, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0035] Optionally, the content of organic components in the charge-transfer coated semiconductor material is 0.5% to 10%.

[0036] The applications include:

[0037] When the charge-transfer coated semiconductor material is a TiO2 nanoarray or TiO2 nanopowder coated with methyl viologen at both ends, the gas to be tested is H2S gas.

[0038] When the charge-transfer coated semiconductor material is a SnO2 nanoarray or SnO2 nanopowder coated with double-terminated phenyl viologen, the gas to be tested is NO2 gas.

[0039] When the charge-transfer coated semiconductor material is a ZnO nanoarray or ZnO nanopowder coated with methyl viologen at both ends, the gas to be tested is H2S gas.

[0040] When the charge-transfer coated semiconductor material is UIO-66 powder coated with 7,7,8,8-tetracyanoquinone dimethane (TCNQ), the gas to be tested is CO gas;

[0041] When the charge-transfer coated semiconductor material is Cu-HTTP powder coated with methyl viologen at one end, the gas to be tested is NO gas.

[0042] When the charge-transfer coated semiconductor material is ZnS powder coated with methyl viologen at one end, the gas to be tested is NH3 gas.

[0043] When the charge-transfer coated semiconductor material is MoS2 powder coated with methyl viologen at one end, the gas to be tested is H2S gas.

[0044] When the charge-transfer coated semiconductor material is P3HT powder coated with ethyl viologen at one end, the gas to be tested is CH4 gas.

[0045] When the charge-transfer coated semiconductor material is COF-102 powder coated with ethyl viologen at both ends, the gas to be tested is C2H2 gas.

[0046] When the charge-transfer coated semiconductor material is Cu-HTTP powder coated with methyl viologen at one end, the gas to be tested is NO gas.

[0047] The beneficial effects that this application can produce include:

[0048] The application of charge-transfer coated semiconductor materials in gas-sensitive sensors provided in this application differs from existing chemielectric resistive semiconductor materials. This application uses charge-transfer coated semiconductor materials as gas-sensitive materials, introducing organic matter onto the surface of the initial semiconductor and using charge-transfer interactions to chemically coat the semiconductor with organic components. This charge-transfer interaction enhances and balances many gas-sensitive properties of the initial semiconductor material (stability, sensitivity, response and recovery speed, operating temperature, and selectivity). Compared with existing semiconductor material optimization methods, this application uses a method of introducing organic matter into the finished semiconductor material to form a charge-transfer coated composite material, which retains the basic properties of the initial semiconductor and reduces application costs by simplifying the material preparation process, thus possessing universality. Attached Figure Description

[0049] Figure 1 shows the morphological and physical property changes of the TiO2 nanoarray before and after coating in Example 1 of this application: (a) is a top-view electron microscope image of the TiO2 nanoarray (AA), (b) and (c) are top-view electron microscope images and cross-sectional views of the TiO2 nanoarray (AA@dimethylvioletin) coated with methyl viologen. (d) is a schematic diagram of the color change of the TiO2 nanoarray film before and after charge transfer coating.

[0050] Figure 2The UV-Vis diffuse reflectance spectra of the TiO2 nanoarray (AA@dimethylvioletin) and the TiO2 nanoarray (AA) prepared in Example 1 of this application.

[0051] Figure 3 shows the response time of (a) TiO2 nanoarray (AA@dimethylvioletin) and (b) TiO2 nanoarray (AA) to pure H2S gas at room temperature in Example 1 of this application.

[0052] Figure 4 This is a comparison chart showing the percentage response of the TiO2 nanoarray (AA@dimethylvioletin) coated with dimethylvioletin in Example 1 of this application to H2S and interfering gases at room temperature.

[0053] Figure 5 The response time diagrams of the TiO2 nanoarray (AA@dimethylvioletin) and the TiO2 nanoarray (AA) coated with dimethyl viologen in Example 1 of this application are shown to the stability of 10 ppm pure H2S gas at room temperature. Detailed Implementation

[0054] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0055] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0056] The dimethyl viologen powder used in the examples was synthesized based on a previously reported method: 4,4'-bipyridine (8.0 g, 51.2 mmol) and chloroacetic acid (12.2 g, 129.1 mmol) were dissolved in 80 mL of acetonitrile, and the mixture was stirred and refluxed at 88 °C for 36 hours. The reaction was then stopped, cooled to room temperature, and the solid product was collected by vacuum filtration and washed 3-5 times with hot acetonitrile, N,N'-dimethylacetamide, and dichloromethane until the sample turned white. The collected product was then vacuum dried in an 80 °C vacuum oven to obtain a white powder.

[0057] The synthesis of the diphenyl viologen powder used in this example followed the method previously reported in the literature. The entire synthesis process consisted of two key steps. First, 4,4'-bipyridine (12.0 g, 76.8 mmol) and 1-chloro-2,4-dinitrobenzene (51.6 g, 254.4 mmol) were dissolved together in 200 mL of acetonitrile. The solution was stirred and refluxed at a constant temperature of 95°C for 60 hours. After the reaction was complete, the mixture was cooled to room temperature, and the resulting solid product was collected by vacuum filtration. To remove residual impurities, the product was washed multiple times with hot acetonitrile, 3 to 5 times each time. Finally, the collected product was placed in a vacuum oven at 80°C for vacuum drying to remove residual moisture and solvent, yielding a pure white powdery product from the first step. Step 2: First, aniline (4575 μL, 50.2 mmol) was mixed with the product from Step 1 (13.5 g, 24.1 mmol). Then, 100 mL of N,N'-dimethylacetamide was slowly added dropwise using a constant-pressure dropping funnel. Stirring was maintained during the addition to ensure complete dissolution of both substances in the N,N'-dimethylacetamide. The resulting solution was then stirred at a constant temperature of 93 °C for 12 hours. Afterward, the reaction temperature was lowered to 50 °C, and 500 mL of ethyl acetate was added dropwise using a constant-pressure dropping funnel. After the reaction was complete, the crude product was collected again by vacuum filtration and washed repeatedly with hot N,N'-dimethylacetamide and ethyl acetate until the filtrate was colorless. To further improve the purity of the product, the powdered crude product was recrystallized in methanol. After removing the filter residue by filtration, the methanol solvent was removed using a vacuum rotary evaporator, finally yielding a reddish-brown crystalline product of di-terminated phenyl viologen.

[0058] The TCNQ solid powder used in the examples was purchased commercially from Adamas.

[0059] The TiO2 nanoarray thin films used in the examples were prepared according to the literature (DOI: doi.org / 10.1002 / ange.202111519).

[0060] The SnO2 nanoarray thin film used in the examples was prepared according to the literature (DOI: 10.1002 / solr.201800133).

[0061] The UIO-66 semiconductor powder used in the examples was purchased commercially from Adamas Corporation.

[0062] The Cu-HTTP semiconductor powder used in the examples was prepared according to the literature (DOI: doi.org / 10.1002 / ange.202212797).

[0063] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0064] The gas detection method in this embodiment is as follows: a silver paste double probe method is used, in which a 50-micrometer diameter silver wire is attached to silver paste as a conductive circuit. This method is also used in the fabrication of chemiluminescence sensors, where a pair of parallel electrodes are connected to both ends of the thin film as the electrode portion of the sensor. These sensors were subsequently tested in a previously reported homemade sensing system. The sensor device was placed in an opaque, sealed quartz chamber, using dry air as the carrier gas at room temperature. To conduct gas-sensing experiments, we monitored the change in DC current of the device under different concentrations of the target gas. Measurements of the sensor device were performed using a DC circuit with a 5V bias voltage, and electrical performance tests were conducted using a Keithley 2602B semiconductor measuring instrument. The target gas was precisely controlled by a mass flow controller (CS-200C, manufactured by Beijing Qixing Mass Flow Electronic Equipment Manufacturing Co., Ltd.), where a qualified gas mixture from Beijing Huayuan Gas Chemical Co., Ltd., China, was mixed with dry air in an appropriate ratio and introduced into the quartz tube. Throughout the process, the gas flow rate remained constant at 200 mL / min. All sensing measurements were performed under standard environmental conditions. The above gas detection method can simultaneously obtain performance data such as the gas sensor's response time, responsivity, and stability to gas.

[0065] The gases used in this application for testing the gas responsiveness include those of equal concentration: hydrogen sulfide, nitrogen dioxide, nitric oxide, carbon monoxide, carbon dioxide, ammonia, methane, sulfur dioxide, sulfur trioxide, hydrogen, acetylene, ethylene, ethane, methanol, ethanol, and acetone. In specific tests, the gas with high selectivity corresponding to the charge-transfer coated semiconductor material (the test gas) is one of the above gases; other gases with low selectivity are referred to as interfering gases.

[0066] The preparation of the charge-transfer coated semiconductor material in this application is based on the applicant's earlier patent application with publication number CN115672397A.

[0067] According to one embodiment of this application, the charge-transfer coated semiconductor material is prepared by a method comprising the following steps: mixing materials containing the organic components and solvent to obtain a coating solution; immersing and stirring the initial semiconductor in the coating solution to form a coating layer, and then washing and drying to obtain the charge-transfer coated semiconductor material.

[0068] According to one embodiment of this application, the charge-transfer coated semiconductor material is prepared by a method comprising the following steps: mixing materials containing the organic components and solvent to obtain a coating solution; dispersing the mixture of the initial semiconductor and the coating solution to form a coating layer; and then washing and drying to obtain the charge-transfer coated semiconductor material.

[0069] This application utilizes the change in conductivity or resistivity of charge-transfer coated semiconductor materials upon contact with a target gas for detection. In gas detection applications, the gas-sensitive material employs an organic component coating the semiconductor, which is bonded to the semiconductor through charge-transfer interactions (i.e., a net charge transfer occurs between them, resulting in electrostatic interactions). The presence of these charge-transfer interactions improves the carrier mobility and charge-separated state lifetime of the semiconductor, thereby enhancing gas detection sensitivity and reducing operating temperature. Furthermore, the redox properties of the organic coating component enhance gas selectivity. Compared to the original semiconductor, this type of material exhibits significant improvements in gas detection performance, including selectivity, stability, response speed, sensitivity, and operating temperature, enabling gas detection at room temperature.

[0070] Preparation Example 1

[0071] Charge-transfer coated semiconductor materials were prepared using an in-situ stirring-immersion synthesis method: 200 mg of dimethyl viologen solid powder was completely dissolved in 20 mL of deionized water to prepare a dimethyl viologen aqueous solution. A TiO2 (initial semiconductor) nanoarray film was fixed with a clip and suspended in the dimethyl viologen aqueous solution (without touching the bottom or the stir bar). It was then placed on a stirrer and stirred for 5 days. After stirring, the TiO2 nanoarray film was removed and immersed in deionized water for 1 day to remove unreacted dimethyl viologen electron acceptor molecules. Finally, it was removed from the deionized water and allowed to air dry to obtain the charge-transfer coated semiconductor, namely, a dimethyl viologen-coated TiO2 nanoarray, labeled AA@dimethyl viologen.

[0072] Morphological changes of TiO2 (initial semiconductor) nanoarrays before and after coating during in-situ stirring-soaking synthesis process are as follows: Figure 1a to Figure 1d As shown. The UV-Vis diffuse reflectance spectra of TiO2 and AA@dimethylvioletin were analyzed. Figure 2 It can be seen that the AA@dimethylvioletin material has a wider light absorption range than the initial semiconductor. After the charge transfer complex is generated, a red shift of the ultraviolet absorption edge can be clearly observed, indicating the formation of the charge transfer complex.

[0073] Example 1

[0074] Gas-sensing tests were conducted on a TiO2 nanoarray film (AA) and an AA@dimethyl viologen film obtained in Preparation Example 1.

[0075] First, air was introduced to remove impurities, then pure H2S gas was introduced to test the changes in the electrical properties of the material. The tests revealed that at room temperature (20-25℃), the responsiveness of the TiO2 nanoarray coated with methyl viologen at both ends to H2S gas was 3000 times that of the TiO2 nanoarray at room temperature. This indicates that the charge-transfer coated semiconductor material, due to the organic coating on its surface, undergoes a new adsorption reaction with the gas, thereby... Figure 3a and Figure 3b The comparison shows that the AA@dimethyl viologen gas-sensitive material used in this application has excellent gas-sensitive adsorption and desorption capabilities. The percentage comparison of the response of AA@dimethyl viologen to H2S and interfering gases at room temperature is shown in the figure below. Figure 4 As shown, this demonstrates that AA@dimethyl viologen exhibits good selectivity for the analyte gas. The response time diagrams of the AA@dimethyl viologen-coated TiO2 nanoarray and the TiO2 nanoarray (AA) to 10 ppm pure H2S gas at room temperature are shown in the figure. Figure 5 As shown, AA@diterminated methyl viologen exhibits good stability.

[0076] Preparation Example 2

[0077] Charge-transfer coated semiconductor materials were prepared using an in-situ stirring-immersion synthesis method. The preparation method and conditions were the same as in Preparation Example 1, except that the dimethyl viologen solid powder was replaced with diphenyl viologen solid powder, and the TiO2 (initial semiconductor) nanoarray film was replaced with SnO2 nanoarray film. Charge-transfer coated semiconductors, namely diphenyl viologen-coated SnO2 nanoarrays, were obtained and labeled as AA@diphenyl viologen.

[0078] Example 2

[0079] Gas-sensing tests were conducted on a SnO2 nanoarray film and an AA@dual-terminated phenyl violite film obtained in Preparation Example 2.

[0080] First, air was introduced to remove impurities, then pure NO2 gas was introduced to test the changes in the electrical properties of the material. The tests revealed that at room temperature (20-25℃), the responsiveness of the SnO2 nanoarray coated with phenyl viologen to NO2 gas was 500 times that of the SnO2 nanoarray at room temperature. This indicates that the charge-transfer coated semiconductor material, due to the organic coating on its surface, exhibits a new adsorption reaction to the gas. The gas-sensitive material provided in this application possesses excellent gas-sensitive adsorption-desorption capabilities. The responsiveness of AA@phenyl viologen to NO2 and interfering gases at room temperature was tested, showing good selectivity for the test gas, similar to Example 1. The responsiveness of the SnO2 nanoarray coated with phenyl viologen (AA@phenyl viologen) and the TiO2 nanoarray (AA) to 10 ppm pure NO2 gas at room temperature was tested, and the results were similar to those in Example 1. AA@phenyl viologen also exhibits good stability.

[0081] Preparation Example 3

[0082] Charge-transfer coated semiconductor materials were prepared by in-situ stirring-immersion synthesis: 200 mg of TCNQ solid powder was completely dissolved in 20 mL of diethyl ether to prepare a TCNQ diethyl ether solution. 3 mg of UIO-66 powder was immersed in the TCNQ diethyl ether solution and stirred on a stirrer for 3 days. After stirring, the mixture was filtered, washed, centrifuged, and dried to remove unreacted TCNQ molecules, thus obtaining a charge-transfer coated semiconductor, namely TCNQ-coated UIO-66 powder, labeled as UIO-66 semiconductor@TCNQ.

[0083] Example 3

[0084] 3 mg of UIO-66 powder and 3 mg of UIO-66 semiconductor @TCNQ powder obtained in Preparation Example 3 were respectively subjected to gas-sensitive sensing tests:

[0085] First, air was introduced to remove impurities, then pure CO gas was introduced to test the changes in the electrical properties of the material. The tests revealed that at room temperature (20-25℃), the responsiveness of the UIO-66 semiconductor@TCNQ powder to CO gas was 1200 times that of UIO-66, indicating that the charge-transfer coated semiconductor material, due to its surface coating with organic matter, exhibits a new adsorption reaction to the gas. The gas-sensitive material provided in this application possesses excellent gas-sensitive adsorption-desorption capabilities. The responsiveness of the UIO-66 semiconductor@TCNQ to CO and interfering gases at room temperature was tested, and the results showed good selectivity for the test gas, similar to Example 1. The responsiveness of the TCNQ-coated UIO-66 powder (UIO-66 semiconductor@TCNQ) and UIO-66 powder to 10ppm pure CO gas at room temperature was tested, and the results were similar to those in Example 1, indicating that the UIO-66 semiconductor@TCNQ also exhibits good stability.

[0086] Preparation Example 4

[0087] Charge-transfer coated semiconductor materials were prepared by in-situ stirring-immersion synthesis. The preparation method and conditions were the same as in Preparation Example 3, except that TCNQ solid powder was replaced with single-terminated methyl viologen solid powder and UIO-66 powder was replaced with Cu-HTTP powder. Charge-transfer coated semiconductors were obtained, namely Cu-HTTP powder coated with single-terminated methyl viologen, labeled as Cu-HTTP@single-terminated methyl viologen.

[0088] Example 4

[0089] Gas-sensitive sensing tests were performed on Cu-HTTP powder and a piece of Cu-HTTP@single-terminated methyl viologen powder obtained in Preparation Example 4.

[0090] First, air was introduced to remove impurities, then pure NO gas was introduced to test the changes in the electrical properties of the material. The tests revealed that at room temperature (20-25℃), the responsiveness of Cu-HTTP powder@single-terminated methyl viologen to NO gas was 800 times that of Cu-HTTP powder. This indicates that the charge-transfer coated semiconductor material, due to its surface coating with organic matter, exhibits a new adsorption reaction to the gas. The gas-sensitive material provided in this application possesses excellent gas-sensitive adsorption-desorption capabilities. The responsiveness of Cu-HTTP@single-terminated methyl viologen to NO and interfering gases at room temperature was tested, and the results showed good selectivity for the test gas, similar to Example 1. The responsiveness of Cu-HTTP powder coated with single-terminated methyl viologen (Cu-HTTP@single-terminated methyl viologen) and Cu-HTTP powder to 10 ppm pure NO gas at room temperature was tested, and the results were similar to those in Example 1. Cu-HTTP@single-terminated methyl viologen also exhibits good stability.

[0091] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. The application of a charge-transfer coated semiconductor material in a gas-sensitive sensor, characterized in that, include: Contact the charge-transfer coated semiconductor material with the gas to be tested; The charge-transfer coated semiconductor material is: Gas-sensitive materials are formed by coating organic components onto the outer surface of an initial semiconductor through charge transfer.

2. The application according to claim 1, characterized in that, The operating temperature of the gas-sensitive sensor is 0~200℃.

3. The application according to claim 1, characterized in that, The gas to be tested is an oxidizing gas and / or a reducing gas.

4. The application according to claim 1, characterized in that, The gas to be tested is selected from at least one of hydrogen sulfide, nitrogen dioxide, carbon monoxide, ammonia, sulfur dioxide, nitric oxide, and methane.

5. The application according to claim 1, characterized in that, The morphology of the initial semiconductor is selected from at least one of micron or nanostructures, thin films, and bulk materials; The micron or nanostructure is selected from at least one of sheet-like, rod-like, spherical, or array-like structures of nano or micron size.

6. The application according to claim 1, characterized in that, The initial semiconductor is selected from at least one of elemental semiconductors, metal compound semiconductors, and organic compound semiconductors.

7. The application according to claim 6, characterized in that, The elemental semiconductor is selected from at least one of silicon, germanium, phosphorus, selenium, antimony, and boron.

8. The application according to claim 6, characterized in that, The metal compound semiconductor is selected from at least one of metal oxides, sulfides, selenides, tellurides, phosphides, carbides, nitrides, and halides.

9. The application according to claim 8, characterized in that, The metal oxide is selected from at least one of ZnO, TiO2, SnO2, WO3, Fe2O3, In2O3, CuO, Co3O4, Cr2O3, NiO, Mn3O4, and ZrO2.

10. The application according to claim 8, characterized in that, The sulfide is selected from at least one of ZnS, CdS, MoS2, and WS2.

11. The application according to claim 6, characterized in that, The organic compound semiconductor is selected from coordination polymers, covalent organic frameworks (COFs), hydrogen-bonded organic frameworks, and conductive polymer semiconductors.

12. The application according to claim 11, characterized in that, The coordination polymer is selected from at least one of MOF-5, MOF-177, MOF-210, MOF-303, IRMofF series, UIO series, MIL series, and HTTP series.

13. The application according to claim 11, characterized in that, The covalent organic framework (COF) is selected from at least one of boron-containing COF materials, imine-based COF materials, triazine-based COF materials, epoxy-based COF materials, and anhydride-based COF materials.

14. The application according to claim 1, characterized in that, The organic component is selected from electron-donating organic components and / or electron-gaining organic components.

15. The application according to claim 14, characterized in that, The electron-donating organic component is selected from at least one of polythiophene, polyphenylene ethylene and its derivatives, polyaniline, polyfluorene and its derivatives, organofullerene derivatives, polypyrrole, and poly(p-phenylene ethylene).

16. The application according to claim 14, characterized in that, The electron-degrading organic component is selected from at least one of fullerene, perylenetetramethylenediimide, perylenetetramethylenediimide, isoindigo, methyl isoindigo, viologen and its derivatives, 7,7,8,8-tetracyanoquinone dimethyl ether and its derivatives, polythiadiazole, poly(p-phenylene), polytriarylamine and its derivatives.

17. The application according to claim 1, characterized in that, The charge-transfer coated semiconductor material is prepared by a method comprising the following steps: S1. Mix the materials containing the organic components and solvent to obtain a coating solution; S2. The initial semiconductor is immersed in a coating solution and stirred, or the initial semiconductor is mixed with a coating solution and dispersed to form a coating layer. Then, it is washed and dried to obtain a charge transfer coated semiconductor material.

18. The application according to claim 17, characterized in that, The solvent is selected from at least one of water, ethanol, methanol, acetone, ethylene glycol, N,N-dimethylformamide, and N,N-dimethylacetamide.

19. The application according to claim 17, characterized in that, The content of organic components in the charge transfer coated semiconductor material is 0.5-10%.

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