Compounds for detecting dmmp, dmmp sensors, and methods of making

Abstract

The application discloses a compound for detecting DMMP, a DMMP sensor and a preparation method, the compound has a structure shown in general formula 1; and the surface of a silicon nanobelt of the DMMP sensor is decorated with the compound. The compound can be specifically combined with DMMP, and can be firmly combined with a silicon substrate through a covalent bond to construct a silicon-based gas sensor. After the compound is combined with DMMP, an electric response signal can be generated, so that the compound can be applied to the silicon-based gas sensor, and the silicon-based gas sensor has the ability of specifically identifying DMMP. The sensor can quickly realize effective gas detection on DMMP, and has good repeatability and selectivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas sensors, and particularly relates to a compound for detecting DMMP, a DMMP sensor and a preparation method. BACKGROUND

[0002] In order to prevent and cope with such invisible toxic gas in the air, it is of great significance to determine the influence range and develop gas detection technology for nerve agents such as sarin. Therefore, a large number of studies have been carried out around DMMP, a sarin simulant.

[0003] Traditional DMMP detection methods mainly include gas chromatography technology, ion mobility spectrum technology and infrared spectrum technology. These methods are widely used in laboratory environments due to their low detection limit and high precision. However, these traditional technologies also have many limitations, such as expensive equipment, large size, complex operation and the need for professional technicians for maintenance and operation. In addition, the detection process usually takes a long time, which greatly reduces its applicability in mobile detection and on-site rapid analysis, especially the real-time response requirements of single-point toxic gas early warning and wearable warning devices. In actual application scenarios, these deficiencies seriously limit the effectiveness of traditional detection technology in dynamic and complex environments, and the demand for developing portable sensors that can achieve high selectivity and high sensitivity detection is increasingly urgent. SUMMARY

[0004] The purpose of the present application is to provide a compound for detecting DMMP, a DMMP sensor and a preparation method, to solve the technical problems of long time consumption, low applicability in mobile detection and on-site rapid analysis, and difficulty in meeting real-time response requirements of traditional DMMP detection methods.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a compound for detecting DMMP, which has the structure shown in the following general formula 1.

[0006]

General Formula 1

[0007] In the general formula 1, R1 is selected from one of 、 and groups;

[0008] R2, R3, R4 each independently represents a C1-C6 group;

[0009] L1, L2 each independently represents a C1-C12 group;

[0010] R5 is a substituted or unsubstituted alkyl or aryl group;

[0011] Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups are optionally substituted with 0, 1, or more fluorine atoms; the C1-C12 groups are straight-chain, branched, or cyclic groups, and the C1-C12 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C12 groups are optionally substituted with 0, 1, or more fluorine atoms.

[0012] In one or more embodiments, it has the structure shown in the following general formula 2;

[0013] [General Formula 2]: ;

[0014] In the general formula 2, R2, R3, and R4 each independently represent C1 to C6 groups;

[0015] L1 and L2 each independently represent C1~C12 groups;

[0016] N1, N2, N3, N4, and N5 each independently choose either carbon or nitrogen atoms;

[0017] R6 is selected from one of hydrogen, deuterium, halogen, hydroxyl, mercapto, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted amino, substituted or unsubstituted aryl, and substituted or unsubstituted aryloxy.

[0018] The C1-C6 groups are selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylenephenylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

[0019] In one or more embodiments, the C1-C6 groups are methyl groups. In one or more embodiments, the fact that R1, R2, and R3 are all the same indicates that they are methyl groups.

[0020] In one or more embodiments, the structure is shown in general formula 3, general formula 4, general formula 5, general formula 6, general formula 7 or general formula 8;

[0021]

[0022]

[0023]

[0024] In general formulas 3, 4, 5, 6, 7, and 8, R2, R3, and R4 each independently represent methyl, ethyl, propyl, butyl, pentyl, or hexyl.

[0025] To achieve the above objectives, a second aspect of this application provides a method for preparing the compound described in any of the above embodiments, comprising:

[0026] The compound is obtained by condensing a first reactant having the following general formula 10 and a second reactant having the following general formula 11 under the action of a catalyst;

[0027] [General Formula 10]: ;

General Formula 11

[0028] In general formulas 10 and 11, R2, R3, and R4 each independently represent a C1-C6 group; L1 and L2 each independently represent a C1-C12 group; R5 is a substituted or unsubstituted alkyl or aryl group; R7 is selected from amino and carboxyl groups, and when R7 is amino, R8 is selected from carboxyl and... One of them, where R7 is a carboxyl group and R8 is an amino group;

[0029] Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups are optionally substituted with 0, 1, or more fluorine atoms; the C1-C12 groups are straight-chain, branched, or cyclic groups, and the C1-C12 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C12 groups are optionally substituted with 0, 1, or more fluorine atoms.

[0030] In one or more embodiments, the catalyst comprises either 1-ethyl-(3-dimethylaminopropyl)carbodiimide or N-hydroxysuccinimide; in one or more embodiments, the molar ratio of the first reactant, the second reactant, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide is (1~5):(1~5):(0.8~1.2):(0.8~1.2).

[0031] To achieve the above objectives, a third aspect of this application provides a DMMP sensor, comprising:

[0032] A silicon substrate includes a first surface and a second surface disposed opposite to each other; an insulating layer disposed on the first surface; a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer; a plurality of silicon nanoribbons disposed on the surface of the insulating layer, with their two ends respectively connected to the first silicon epitaxial layer and the second silicon epitaxial layer; a source electrode and a drain electrode disposed on the surface of the first silicon epitaxial layer and the surface of the second silicon epitaxial layer, respectively; and a gate electrode disposed on the second surface.

[0033] The first silicon epitaxial layer, the second silicon epitaxial layer, and the silicon nanoribbon have the same conductivity type; the surface of the silicon nanoribbon is modified with a compound as described in any of the above embodiments, wherein the R2, R3, and R4 groups of the compound are replaced so that the compound is covalently connected to the silicon nanoribbon.

[0034] In one or more embodiments, the compound is arranged in a monolayer on the surface of the silicon nanoribbon.

[0035] In one or more embodiments, the silicon nanoribbon has an extension length of 10-100 μm in a first direction, an extension width of 100 nm-10 μm in a second direction, and a thickness of 10-200 nm; wherein, the first direction is the direction from the first silicon epitaxial layer to the second silicon epitaxial layer, and the second direction is perpendicular to the first direction.

[0036] In one or more embodiments, the silicon nanoribbons extend along a first direction, and the plurality of silicon nanoribbons are uniformly spaced along a second direction; wherein, the first direction is the direction from the first silicon epitaxial layer to the second silicon epitaxial layer, and the second direction is perpendicular to the first direction.

[0037] To achieve the above objectives, a fourth aspect of this application provides a method for fabricating a DMMP sensor according to any of the above embodiments, comprising:

[0038] A field-effect transistor (FET) is provided, comprising a silicon substrate, an insulating layer disposed on the surface of the silicon substrate, a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer, and a plurality of silicon nanoribbons disposed on the surface of the insulating layer and connected at both ends to the first silicon epitaxial layer and the second silicon epitaxial layer, respectively; the FET is subjected to hydroxylation treatment with a piranha solution, the piranha solution comprising concentrated sulfuric acid and hydrogen peroxide, to obtain a first silicon wafer; a source and a drain are fabricated on the first silicon wafer to obtain a second silicon wafer; a compound having general formula 1 is grafted onto the surface of the silicon nanoribbons of the second silicon wafer to obtain a third silicon wafer; a gate is fabricated on the third silicon wafer to obtain the DMMP sensor.

[0039] In one or more embodiments, the step of grafting a compound having general formula 1 onto the surface of a silicon nanoribbon of the second silicon wafer includes: modifying the second silicon wafer with a first reactant having general formula 10; and performing a condensation reaction between the second silicon wafer modified with the first reactant and a second reactant having general formula 11 in the presence of a catalyst.

[0040] [General Formula 10]: ;

General Formula 11

[0041] In general formulas 10 and 11, R2, R3, and R4 each independently represent a C1-C6 group; L1 and L2 each independently represent a C1-C12 group; R5 is a substituted or unsubstituted alkyl or aryl group; R7 is selected from amino and carboxyl groups, and when R7 is amino, R8 is selected from carboxyl and... One of them, where R7 is a carboxyl group and R8 is an amino group;

[0042] Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups are optionally substituted with 0, 1, or more fluorine atoms; the C1-C12 groups are straight-chain, branched, or cyclic groups, and the C1-C12 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C12 groups are optionally substituted with 0, 1, or more fluorine atoms.

[0043] In one or more embodiments, the catalyst comprises either 1-ethyl-(3-dimethylaminopropyl)carbodiimide or N-hydroxysuccinimide.

[0044] In one or more embodiments, the step of modifying the second silicon wafer with the first reactant specifically involves: dissolving the first reactant in a solvent to obtain a first immersion solution; immersing the second silicon wafer in the first immersion solution, then removing it, cleaning it, and drying it; wherein the immersion time is 0.5 to 5 hours, and the volume fraction of the first reactant in the first immersion solution is 1 to 10%.

[0045] In one or more embodiments, the step of performing a condensation reaction between the second reactant and the second silicon wafer modified with the first reactant under the action of a catalyst specifically involves: dissolving the second reactant in a solvent, and then mixing it with an N-hydroxysuccinimide solution and a 1-ethyl-(3-dimethylaminopropyl)carbodiimide solution to obtain a second immersion solution; immersing the second silicon wafer modified with the first reactant in the second immersion solution, followed by washing and drying; wherein the concentration of N-hydroxysuccinimide in the second immersion solution is 0.01~0.05 mol / L, the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 0.01~0.05 mol / L, the concentration of the second reactant is 0.02~0.5 mol / L, and the immersion time is 2~5 h.

[0046] In one or more embodiments, before the step of performing a condensation reaction between the second reactant and the second silicon wafer modified with the first reactant under the action of a catalyst, the method further includes: immersing the second silicon wafer modified with the first reactant in water, then removing it and drying it; wherein the immersion time is 3 to 10 hours.

[0047] In one or more embodiments, the step of grafting a compound having general formula 1 onto the surface of a silicon nanoribbon of the second silicon wafer includes: dissolving the compound in a solvent to obtain a third soaking solution; immersing the second silicon wafer in the third soaking solution, then removing it and drying it; wherein the concentration of the compound in the third soaking solution is 0.02~0.5 mol / L, and the soaking time is 0.5-5 h.

[0048] In one or more embodiments, the piranha solution is obtained by mixing 30% hydrogen peroxide and 98% concentrated sulfuric acid in a volume ratio of 3:(7~9).

[0049] In one or more embodiments, the hydroxylation treatment specifically involves: placing the field-effect transistor in a container, pouring the piranha solution into the container, heating a water bath, and then removing the field-effect transistor, cleaning, and drying; wherein the temperature of the water bath is 70~95 ℃ and the time is 10~60 min.

[0050] The advantages of this application, which differ from existing technologies, are:

[0051] The compound of this application can specifically bind to DMMP and can be firmly covalently bonded to a silicon substrate to construct a silicon-based gas sensor. After binding to DMMP, the compound can generate an electrical response signal, enabling its application in silicon-based gas sensors to specifically identify DMMP. The DMMP sensor of this application can generate an electrical response signal when in a DMMP gas atmosphere, with a short response time, enabling rapid and effective gas detection of DMMP. The device exhibits good repeatability and selectivity, achieving excellent sensing performance for DMMP. At the same time, the device has the advantages of convenient fabrication and compatibility with modern chip manufacturing processes, laying the foundation for realizing chip-level integrated DMMP gas sensors. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0053] Figure 1 This is a schematic diagram of one embodiment of the DMMP sensor of this application; Figure 2 This is a schematic diagram of the DMMP sensor of this application; Figure 3 This is a schematic flowchart of one embodiment of the method for fabricating the DMMP sensor of this application; Figure 4 This is a flowchart illustrating the fabrication process of one embodiment of the field-effect transistor of this application; Figure 5 yes Figure 3 A flowchart illustrating one embodiment corresponding to S400; Figure 6 yes Figure 5 A schematic diagram illustrating the effect of one embodiment corresponding to S402; Figure 7 This is the experimental data graph from Example 1 of the effect of this application; Figure 8 This is the XPS characterization spectrum in Example 2 of this application; Figure 9 This is a graph showing the thickness data of the silicon wafer surface modification layer in Example 3 of this application; Figure 10 This is the surface chemical composition analysis spectrum of the silicon nanoribbons in Example 4 of this application; Figure 11 This is a photograph of the customized gas testing platform used in Example 5 of this application; Figure 12 This is a dynamic response data graph of the sensor to DMMP in Example 1 of Example 5 of this application; Figure 13 This is the continuous response-recovery cycle curve of the sensor in Example 1 of Embodiment 5 of this application; Figure 14 This is a graph showing the response data of the sensor in Example 1 of Example 5 of this application to 100 ppm DMMP and other VOCs; Figure 15 The response curves of the sensors in Example 1 and Comparative Example 3 of this application to 80 ppm DMMP are shown in Example 5 of this application. Detailed Implementation

[0054] To address the problems of traditional DMMP detection methods, the applicant has developed a compound that specifically binds to DMMP, exhibiting high selectivity and high sensitivity. This compound can be applied to DMMP detection, enabling real-time response to DMMP concentration.

[0055] Specifically, the compound has the structure shown in general formula 1;

[0056] [General Formula 1]: ;

[0057] In general formula 1, R1 is selected from... , and One of the groups; R2, R3, and R4 each independently represent C1-C6 groups; L1 and L2 each independently represent C1-C12 groups; R5 is a substituted or unsubstituted alkyl or aryl group;

[0058] Wherein, C1 to C6 groups are straight-chain, branched, or cyclic groups, and C1 to C6 groups are saturated, monounsaturated, or polyunsaturated groups, and C1 to C6 groups may optionally have 0, 1, or more fluorine atoms substituted; C1 to C12 groups are straight-chain, branched, or cyclic groups, and C1 to C12 groups are saturated, monounsaturated, or polyunsaturated groups, and C1 to C12 groups may optionally have 0, 1, or more fluorine atoms substituted.

[0059] The phosphorus-oxygen double bond (P=O) in DMMP is an important characteristic group, serving as both a good hydrogen bond acceptor and a typical Lewis base. The compound represented by general formula 1 has a thiourea group (-NH-C(S)-NH-), containing a sulfur atom (S) and a carbonyl-like thiocarbonyl structure (C=S), simultaneously bonded to two amino groups (-NH-). Due to the excellent hydrogen bond donor properties of the thiourea group, where the proton in the NH group can form a hydrogen bond with the oxygen in the phosphonate ester, it can specifically bind to DMMP.

[0060] Furthermore, the compounds shown in Formula 1 have three binding sites at positions R2, R3, and R4, allowing them to covalently bond firmly to a silicon substrate to construct a silicon-based gas sensor. They can also covalently bond firmly to adjacent compounds to form a layer structure. When this compound binds to DMMP, it generates an electrical response signal, enabling the silicon-based gas sensor to specifically recognize DMMP. Alternatively, the compounds of Formula 1 can also be incorporated into a mass sensor. When this compound adsorbs DMMP, it causes a mass change, giving the mass sensor the ability to specifically recognize DMMP.

[0061] More specifically, in one embodiment, the R5 group in general formula 1 above may be a cyclic group, and the compound may have the structure shown in general formula 2 below;

[0062] [General Formula 2]: ;

[0063] In general formula 2, R2, R3, and R4 each independently represent C1 to C6 groups; L1 and L2 each independently represent C1 to C12 groups; N1, N2, N3, N4, and N5 each independently choose a carbon atom or a nitrogen atom; R6 is selected from one of hydrogen, deuterium, halogen, hydroxyl, mercapto, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted amino, substituted or unsubstituted aryl, and substituted or unsubstituted aryloxy.

[0064] The C1-C6 groups are selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylenephenylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

[0065] More specifically, in one embodiment, the compound may have the structure shown in general formulas 3, 4, 5, 6, 7, or 8:

[0066]

[0067]

[0068]

[0069] In general formulas 3, 4, 5, 6, 7, and 8, R2, R3, and R4 each independently represent a group selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl.

[0070] This application also provides a method for preparing the above-mentioned compound, the method comprising:

[0071] A first reactant having the following general formula 10 and a second reactant having the following general formula 11 are subjected to a condensation reaction in the presence of a catalyst to obtain a compound.

[0072] The catalysts include 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS).

[0073] [General Formula 10]: ;

General Formula 11

[0074] In general formulas 10 and 11, R2, R3, and R4 each independently represent C1-C6 groups; L1 and L2 each independently represent C1-C12 groups; R5 is a substituted or unsubstituted alkyl or aryl group; R7 is selected from amino and carboxyl groups, and when R7 is amino, R8 is selected from carboxyl and... One of them, where R7 is a carboxyl group and R8 is an amino group;

[0075] Specifically, the reaction formula for the above preparation method can be one of the following formulas:

[0076] ;

[0077] ;

[0078] .

[0079] In one embodiment, the molar ratio of the first reactant, the second reactant, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide can be: (1~5):(1~5):(0.8~1.2):(0.8~1.2).

[0080] This application also provides a DMMP sensor based on the above-mentioned compound, specifically a silicon nanoribbon field-effect transistor (SiNW FET) gas sensor, which can achieve high sensitivity and high selectivity detection of DMMP.

[0081] Specifically, please refer to Figure 1 , Figure 1 This is a schematic diagram of one embodiment of the DMMP sensor of this application.

[0082] like Figure 1 As shown, the sensor includes a silicon substrate 100, which has a first surface and a second surface disposed opposite to each other. An insulating layer 200 is disposed on the first surface, and a first silicon epitaxial layer 300 and a second silicon epitaxial layer 400 disposed on the insulating layer 200 at intervals.

[0083] Multiple silicon nanoribbons 500 are also arranged on the insulating layer 200, and the two ends of the multiple silicon nanoribbons 500 are respectively connected to the first silicon epitaxial layer 300 and the second silicon epitaxial layer 400.

[0084] A source electrode 600 and a drain electrode 700 are respectively arranged on the first silicon epitaxial layer 300 and the second silicon epitaxial layer 400, and a gate electrode 800 is arranged on the second surface.

[0085] In one embodiment, the silicon substrate 100 may be an intrinsic silicon substrate 100, and the insulating layer 200 may be a silicon dioxide insulating layer 200.

[0086] The first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 have the same conductivity type. For example, the first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 can be p-type semiconductor layers doped with a first conductivity type dopant, such as Mg, Zn, Ca, Sr, and Ba; or they can be n-type semiconductor layers doped with a second conductivity type dopant, such as Si, Ge, Sn, Se, and Te.

[0087] The surface of the silicon nanoribbon 500 is modified with the compound of any of the above embodiments. During the modification process, the R2, R3, and R4 groups of the compound are replaced so that the compound is covalently connected to the silicon nanoribbon 500.

[0088] Specifically, the connection structure between the silicon nanoribbons 500 and the above-mentioned compound can be as follows:

[0089] ;

[0090] To optimize the distance between the thiourea groups and silicon and obtain the electrical response signal generated after binding DMMP, in a preferred embodiment, the compound can adopt the structure shown in general formula 3. In this case, the connection structure between the silicon nanoribbon 500 and the above compound can be as follows:

[0091] .

[0092] To optimize the sensor's response performance, in one embodiment, the compounds are arranged in a monolayer on the surface of silicon nanoribbons 500, where each compound in the monolayer is stably connected to the silicon nanoribbons 500 by covalent bonds.

[0093] In one embodiment, to optimize sensor performance, the silicon nanoribbon 500 can have an extension length of 50 μm in the first direction x, an extension width of 2 μm in the second direction y, and a thickness of 145 nm.

[0094] Furthermore, the silicon nanoribbons 500 can be extended along the first direction x, and multiple silicon nanoribbons 500 can be evenly spaced along the second direction y.

[0095] Based on the DMMP sensors described in the above embodiments, when in a DMMP gas atmosphere, the hydrogen atoms in the amino group of the thiourea group form hydrogen bonds with the oxygen atoms in the phosphorus-oxygen double bond of the DMMP molecule, resulting in specific physical adsorption of the DMMP molecule. Subsequently, some electrons are transferred from the DMMP molecule to the surface of the silicon nanoribbon 500, forming an electric field effect that accumulates negative charges, causing an increase in positive charges on the surface of the silicon nanoribbon 500 and generating an electrical response signal.

[0096] Please see Figure 2 , Figure 2 This is a schematic diagram of the principle of the DMMP sensor of this application, where a is a schematic diagram of the hydrogen bonding adsorption and electron transfer of DMMP with thiourea groups; b is a schematic diagram of the change of internal charge carriers after DMMP molecules are adsorbed on the surface of silicon nanoribbon 500.

[0097] exist Figure 2 In the illustrated embodiment, the first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 are all p-type silicon, with holes as the primary charge carriers. An increase in the positive charge at the top results in an increase in holes, leading to increased conductivity and a signal with increased current. In another embodiment, when the first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 are all n-type silicon, electrons are the primary charge carriers. An increase in the positive charge at the top results in a decrease in electrons, leading to decreased conductivity and a signal with decreased current. Preferably, the first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 are all p-type silicon to improve test sensitivity.

[0098] The above embodiments utilize silicon nanoribbon field-effect transistors to achieve effective gas detection of DMMP. The device exhibits good repeatability and selectivity, achieving excellent sensing performance for DMMP. At the same time, the device has the advantages of convenient fabrication and compatibility with modern chip manufacturing processes, laying the foundation for realizing chip-level integrated DMMP gas sensors.

[0099] It should be noted that this application only discloses a silicon nanoribbon field-effect transistor sensor using the above-mentioned compound. This compound can also be applied to other sensors, such as other silicon-based electrical signal sensors or silicon-based mass sensors, etc., and can also achieve specific detection of DMMP. It is understood that the detection sensitivity of different sensors may vary.

[0100] This application also provides a method for fabricating a DMMP sensor according to any of the above embodiments. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a schematic flowchart of one embodiment of the method for fabricating the DMMP sensor of this application.

[0101] like Figure 3 As shown, the preparation method includes:

[0102] S100 provides a field-effect transistor.

[0103] The field-effect transistor includes a silicon substrate, an insulating layer disposed on the surface of the silicon substrate, a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer, and a plurality of silicon nanoribbons disposed on the surface of the insulating layer and connected at both ends to the first silicon epitaxial layer and the second silicon epitaxial layer, respectively.

[0104] In one embodiment, the field-effect transistor can be fabricated using SOI wafers as raw materials and a top-down method. (See [link to relevant documentation]). Figure 4 , Figure 4 This is a flowchart illustrating the fabrication process of one embodiment of the field-effect transistor of this application.

[0105] like Figure 4 As shown, an SOI wafer may include a silicon substrate layer, a silicon oxide insulating layer and a p-type silicon layer stacked sequentially from bottom to top. By performing photolithography and etching processes sequentially on the surface of the p-type silicon layer, the p-type silicon layer can be etched to obtain a first silicon epitaxial layer, a second silicon epitaxial layer and silicon nanoribbons.

[0106] Of course, in other embodiments, a silicon substrate can be used as the raw material, and an insulating layer and a p-type silicon layer can be grown sequentially on the silicon substrate. Then, the p-type silicon layer can be subjected to photolithography and etching processes to obtain a field-effect transistor.

[0107] The aforementioned photolithography and etching processes are well known to those skilled in the art and will not be described in detail here.

[0108] S200. The field-effect transistor is hydroxylated using a piranha solution to obtain the first silicon wafer.

[0109] In order for the compound to be covalently bonded to the silicon nanoribbon, the field-effect transistor needs to be hydroxylated first so that hydroxyl groups are formed on the surface of the silicon nanoribbon.

[0110] Specifically, the field-effect transistor can be hydroxylated using a piranha solution, which is obtained by mixing 30% hydrogen peroxide and 98% concentrated sulfuric acid in a volume ratio of 3:(7~9).

[0111] In one embodiment, the hydroxylation treatment specifically involves: placing the field-effect transistor (FET) in a container, pouring a piranha solution into the container, heating it in a water bath, then removing the FET, cleaning it, and drying it; wherein the water bath temperature can be 70~95 °C, and the time can be 10~60 min. Preferably, the water bath temperature can be 90 °C, and the time can be 30 min.

[0112] It should be noted that during the hydroxylation process, the silicon wafer should be placed in a beaker first, and then the piranha solution should be poured in slowly to prevent excessive bubbles from forming, which could affect subsequent processing. To avoid damage to the electrodes during hydroxylation, the hydroxylation step is performed before electrode preparation in this embodiment.

[0113] S300: The source and drain electrodes are fabricated on the first silicon wafer to obtain the second silicon wafer.

[0114] Specifically, a metal mask can be used to cover the surface of the first silicon wafer, and then metal electrodes can be prepared by metal evaporation on the surfaces of the first and second silicon epitaxial layers.

[0115] S400. A compound having general formula 1 is grafted onto the surface of silicon nanoribbons to obtain a third silicon wafer.

[0116] After the metal electrode is prepared, compounds can be further grafted onto the surface of the silicon nanoribbon.

[0117] In one implementation, please refer to Figure 5 , Figure 5 yes Figure 3 A flowchart illustrating one embodiment corresponding to S400. (For example...) Figure 5 As shown, a method for grafting a compound having general formula 1 onto the surface of a silicon nanoribbon may include:

[0118] S401, The second silicon wafer is modified using a first reactant having general formula 4.

[0119] In one embodiment, the above modification method specifically involves: dissolving the first reactant in a solvent to obtain a first immersion solution; immersing the second silicon wafer in the first immersion solution, then removing it, cleaning it, and drying it; wherein the immersion time can be 0.5 to 5 hours, and the volume fraction of the first reactant in the first immersion solution is 1 to 10%. Preferably, the immersion time can be 2 hours, and the volume fraction of the first reactant in the first immersion solution is 2%.

[0120] In one embodiment, the solvent of the first soaking solution may be ethanol.

[0121] Based on this step, the first reactant can be grafted onto the surface of silicon nanoribbons, and the connection structure between the silicon nanoribbons and the above compound can be as follows: .

[0122] S402. Immerse the second silicon wafer modified with the first reactant in water, then remove it and dry it.

[0123] In order to ensure that the compound having general formula 1 can be arranged in a monolayer on the surface of silicon nanoribbon, in this embodiment, the second silicon wafer grafted with the first reactant is immersed in water to remove the first reactant that is not directly covalently bonded to silicon.

[0124] In one embodiment, the soaking time can be 3 to 10 hours.

[0125] The following example, using the first reactant with L2 as the C1 group and R7 as the amino group, illustrates the effect of S402. Please refer to [link / reference needed].Figure 6 , Figure 6 yes Figure 5 A schematic diagram of the effect of one embodiment corresponding to S402 is shown below. Figure 6 As shown, after soaking, the first reactant that is not covalently bonded to the silicon wafer in the multilayer modified silicon wafer is removed, resulting in a single-layer modified silicon wafer.

[0126] S403, A condensation reaction is carried out between a second reactant having general formula 5 and a second silicon wafer modified with the first reactant under the action of a catalyst.

[0127] The catalysts include 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide.

[0128] In one implementation, the condensation reaction step can be specifically as follows:

[0129] The second reactant was dissolved in a solvent and then mixed with an N-hydroxysuccinimide solution and a 1-ethyl-(3-dimethylaminopropyl)carbodiimide solution to obtain a second soaking solution;

[0130] The second silicon wafer modified with the first reactant is immersed in the second immersion solution, then cleaned and dried;

[0131] The concentration of N-hydroxysuccinimide in the second soaking solution can be 0.01~0.05 mol / L, the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide can be 0.01~0.05 mol / L, the concentration of the second reactant can be 0.02~0.5 mol / L, and the soaking time can be 2~5 h.

[0132] Preferably, the concentration of N-hydroxysuccinimide can be 0.0125 mol / L, the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide can be 0.0125 mol / L, the concentration of the second reactant can be 0.025 mol / L, and the soaking time can be 3 h.

[0133] Understandably, during the soaking process, the first reactant can undergo a carboxyl-amino condensation reaction with the second reactant to generate an amide bond, thereby grafting the compound with general formula 1 onto the silicon surface.

[0134] In another embodiment, the preparation method of the compound having general formula 1 can be directly used to prepare the compound shown in general formula 1 using the first reactant and the second reactant as raw materials. Then, the compound is dissolved in a solvent to obtain a third soaking solution. The second silicon wafer is then soaked in the third soaking solution, removed, and dried to obtain a third silicon wafer.

[0135] The concentration of the compound in the third soaking solution can be 0.02~0.5 mol / L, and the soaking time can be 0.5-5 h.

[0136] S500: A gate is fabricated on the third silicon wafer to obtain a DMMP sensor.

[0137] After the compound grafting is completed, a gate can be fabricated on the back side of the silicon substrate. The gate can be fabricated by bonding a metal thin film or by metal evaporation, both of which can achieve the effect of this embodiment.

[0138] The effects of the technical solution of this application will be further explained in detail below with reference to specific embodiments.

[0139] Example 1:

[0140] A silicon nanoribbon field-effect transistor DMMP sensor, with the structure as follows: Figure 1 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0141] ;

[0142] The sensor was prepared using the following steps:

[0143] Step (1): Using SOI wafers as raw materials, the top silicon layer of the SOI wafer is p-type with a doping concentration of 10. 15 cm -3 The resistivity is 1~10 Ω·cm and the thickness is 140 nm; the silicon substrate thickness is 450 μm and the buried silicon oxide thickness is 450 nm. The SOI wafer is cut into 2 cm square pieces, then immersed in ultrasonic cleaning, photolithography and etching are performed to etch the top silicon layer to obtain the first silicon epitaxial layer, the second silicon epitaxial layer and 20 silicon nanoribbons located between the two. The length of the silicon nanoribbons is 50 μm and the width is 2 μm, thus obtaining the first silicon wafer;

[0144] Step (2): After cleaning the first silicon wafer, place it in a beaker, heat the piranha washing solution (30% hydrogen peroxide and 98% concentrated sulfuric acid, volume ratio 1:3), and perform hydroxylation in a water bath at 90 ℃ for 30 min. Then take it out and rinse it clean to obtain the second silicon wafer.

[0145] Step (3): The metal mask is attached to the surface of the second silicon wafer, and the source and gate are prepared by metal evaporation.

[0146] Step (4): Immerse the second silicon wafer in an ethanol solution of 2% (v / v) of 3-aminopropyltriethoxysilane (APTES), soak for 2 h, then remove it, rinse with deionized water, and dry in a drying oven at 120 ℃ for 2 h.

[0147] Step (5): Soak the second silicon wafer in deionized water for 6 h to hydrolyze it in order to remove APTES molecules that are not directly covalently bonded to silicon;

[0148] Step (6): Mix 0.05 mol / L NHS solution, 0.05 mol / L EDC solution and 0.05 mol / L 2-(3-phenylthiourea)acetic acid solution in a volume ratio of 1:1:2 to form a reaction solution. Immerse the second silicon wafer in the reaction solution for 3 h to allow the amino and carboxyl groups to fully undergo a condensation reaction. Then take it out and rinse it clean to obtain the third silicon wafer.

[0149] Step (7): An indium gallium alloy layer is attached to the back of the silicon substrate to prepare the gate.

[0150] Example 2:

[0151] A silicon nanoribbon field-effect transistor DMMP sensor, with the structure as follows: Figure 1 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0152]

[0153] The preparation method of this sensor is basically the same as that in Example 1, except that:

[0154] In step (4), aminomethyltriethoxysilane is used instead of 3-aminopropyltriethoxysilane in Example 1.

[0155] Example 3:

[0156] A silicon nanoribbon field-effect transistor DMMP sensor, with the structure as follows: Figure 1 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0157] ;

[0158] The preparation method of this sensor is basically the same as that in Example 2, except that:

[0159] In step (6) 2-(3-phenylthiourea)acetic acid is used as an alternative to that in Example 2.

[0160] Example 4:

[0161] A silicon nanoribbon field-effect transistor DMMP sensor, with the structure as follows: Figure 1 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0162] ;

[0163] The preparation method of this sensor is basically the same as that in Example 2, except that:

[0164] In step (4), triethoxysilane acetate is used instead of aminomethyltriethoxysilane in Example 2;

[0165] In step (6) 2-(3-phenylthiourea)acetic acid is used as an alternative to that in Example 2.

[0166] Example 5:

[0167] A silicon nanoribbon field-effect transistor DMMP sensor, with the structure as follows: Figure 1 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0168] .

[0169] The preparation method of this sensor is basically the same as that in Example 2, except that:

[0170] In step (6) 2-(3-phenylthiourea)acetic acid is used as an alternative to that in Example 2.

[0171] Example 6:

[0172] A silicon nanoribbon field-effect transistor DMMP sensor, with the structure as follows: Figure 1 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0173] .

[0174] The preparation method of this sensor is basically the same as that in Example 2, except that:

[0175] In step (6), 2-(3-phenylthiourea)butyric acid is used instead of 2-(3-phenylthiourea)acetic acid in Example 2.

[0176] Comparative Examples 1 and 2:

[0177] A silicon nanoribbon field-effect transistor DMMP sensor is prepared in a manner that is basically the same as that in Example 1, except that step (2) is omitted in the preparation method of Comparative Example 1, while the water bath temperature in step (2) of Comparative Example 2 is 25 °C.

[0178] Comparative Example 3:

[0179] A silicon nanoparticle DMMP sensor, the preparation method includes:

[0180] Step (1): Add 0.1 g of silicon nanoparticle powder and 5 mL of deionized water to a centrifuge tube, sonicate for 5 min, and then use a mixer to shake for 30 min at a speed of 1000 rpm to ensure that the silicon nanoparticles are completely and uniformly dispersed in the deionized water.

[0181] Use a 1.5 cm × 2.5 cm glass slide as the substrate. On the substrate, use transparent adhesive to attach a 1 cm × 0.5 cm rectangular frame. Follow the 100 μL / cm... 2 To prepare the silicon nanoparticle device, add 50 μL of silicon nanoparticle dispersion evenly within a rectangular frame; allow it to stand for a period of time until the deionized water evaporates naturally.

[0182] Steps (2-5): Same as in Example 1, the silicon nanoparticle devices are sequentially subjected to hydroxylation treatment, immersed in an ethanol solution of aminomethyltriethoxysilane, immersed in deionized water, and immersed in the reaction solution.

[0183] Step (6): Electrodes are prepared by connecting copper wires to both ends of the carbon nanoparticle layer using carbon conductive adhesive.

[0184] Example of effect 1:

[0185] Using the second silicon wafer prepared in step (2) of Example 1 and Comparative Examples 1 to 2 as samples, the water contact angle on the surface of the second silicon wafer was measured to obtain... Figure 7 , Figure 7 These are experimental data graphs from Example 1 of this application, where a is the water contact angle image of Comparative Example 1, b is the water contact angle image of Comparative Example 2, c is the water contact angle image of Example 1, and d is a statistical graph of water contact angle.

[0186] like Figure 7 As shown, the surface of the second silicon wafer in Comparative Example 1 that has not undergone hydroxylation treatment has a water contact angle of approximately 55°, and this surface contains a certain amount of hydroxyl groups provided by the native oxide layer.

[0187] After being soaked in a piranha solution at 25 ℃ for 30 minutes, the water contact angle on the surface of the second silicon wafer decreased to about 45°, and the hydroxyl density increased.

[0188] After immersion in a piranha solution at 90 °C for 30 min, the water contact angle on the surface of the second silicon wafer further decreased to approximately 14°, and the hydroxyl density significantly increased. These results indicate that the hydroxylation process employed in Example 1 is highly effective in improving the surface hydroxyl density.

[0189] Example 2:

[0190] XPS analysis was performed on the unmodified bare silicon wafer prepared in step (2) of Example 1 and the APTES-modified silicon wafer prepared in step (3), and the results were obtained. Figure 8 , Figure 8 This is the XPS characterization spectrum in Example 2 of this application.

[0191] like Figure 8 As shown, the surface of the unmodified bare silicon nanoribbons contains three elements: Si, O, and C. This indicates that the surface of the original silicon nanoribbons contains hydroxyl groups and adsorbed carbon after treatment with piranha solution.

[0192] After APTES modification, the surface of silicon micro- and nano-strips showed the addition of N element in addition to Si, O, and C elements. This is consistent with the amino group in the APTES molecule structure, indicating that the -NH2 group was successfully modified onto the surface of the silicon nano-strips, demonstrating that the APTES molecule was successfully modified onto the silicon micro- and nano-strips.

[0193] Example of effect 3:

[0194] The thickness of the surface modification layer of the silicon wafer prepared in steps (2), (3), and (4) of Example 1 was measured using an ellipsometry to obtain the following results. Figure 9 , Figure 9 This is a graph showing the thickness of the silicon wafer surface modification layer in Example 3 of this application.

[0195] like Figure 9 As shown, the surface thickness of the unmodified second silicon wafer prepared in step (2) is approximately 0 nm; the average thickness of the silicon wafer surface modification layer prepared in step (3) is 1.815 nm; and the average thickness of the silicon wafer surface modification layer prepared in step (4) is 0.775 nm.

[0196] Calculations using van der Waals radii to determine the size of APTES molecules revealed that their three-dimensional dimensions range from 0.8 nm to 1.2 nm. Considering that APTES undergoes hydrolysis to generate ethanol during silicon surface modification, resulting in the loss of two carbons and thus a reduction in size, the average thickness of 0.775 nm is consistent with that of a single APTES molecule on the silicon surface. These results demonstrate that the modification method described in Example 1 enables the modification of APTES molecules on the silicon surface to be predominantly monolayered, which is beneficial for subsequent interactions between the modified molecules and the silicon via an electric field.

[0197] Example of effect 4:

[0198] The surface chemical composition of the silicon nanoribbons of the third silicon wafer prepared in step (5) of Example 1 was analyzed, and the following results were obtained. Figure 10 , Figure 10The images show the surface chemical composition analysis of silicon nanoribbons in Example 4 of this application, where a is the XPS full spectrum; b is the carbon element spectrum and peak fitting results; and c is the sulfur element spectrum and peak fitting results.

[0199] like Figure 10 As shown in Figure a, it indicates the presence of five elements on its surface: oxygen, nitrogen, carbon, sulfur, and silicon. The other elements are also present in the surface chemical composition after APTES modification. The presence of sulfur, to some extent, indicates that 2-(3-phenylthiourea)acetic acid successfully condensed on the silicon surface.

[0200] To further confirm this, a refined C 1s peak fitting process was performed on its carbon spectrum, such as... Figure 10 As shown in Figure b, a characteristic peak representing an amide group (-CONH-) is clearly present at 287 eV, indicating that the amidation reaction of fixing the thiourea group to the silicon surface can be carried out effectively.

[0201] like Figure 10 As shown in Figure c, a distinct S element peak can be observed in the spectrum, proving the presence of thiourea groups on the silicon surface.

[0202] Example 5:

[0203] use Figure 11 The customized gas testing platform shown was used for gas-sensing performance testing. Figure 11 These are photographs of the customized gas testing platform used in Example 5 of this application, where a is a top view of the testing platform with the lid open; and b is a side view of the testing platform with the lid closed.

[0204] This custom gas testing platform includes a sample stage and a heating stage located in a sealed chamber with a fixed volume. The desired DMMP gas concentration atmosphere is created by adding a certain amount of DMMP liquid to the heating stage and accelerating the evaporation of the liquid through the heating stage.

[0205] Specifically, the performance parameters tested include responsivity, minimum detection limit, response time, recovery time, repeatability, and selectivity. The electrical signal responsivity is calculated using the following formula:

[0206]

[0207] Response time and recovery time are calculated as the time required to reach 90% of the maximum responsiveness and the time required for the responsiveness to decrease to 90%, respectively.

[0208] First, the sensor from Example 1 was placed on the sample stage. A microsyringe was used to deliver DMMP liquid to the heated platform, and its electrical response to different concentrations of DMMP was tested. Figure 12 .

[0209] Figure 12 This is a dynamic response data graph of the sensor in Example 1 of Example 5 of this application to DMMP. In the graph, a is the dynamic response graph to 80 ppm DMMP, b is a scatter plot and linear fitting of the response to different concentrations of DMMP, and c is the dynamic response-recovery curve for 20-100 ppm DMMP. (The light background in the graph represents the air atmosphere, and the dark background represents the DMMP atmosphere; the concentration is indicated in ppm.)

[0210] like Figure 12 As shown in Figure a, when 80 ppm DMMP was introduced, the current of the sensor in Example 1 increased significantly, from 0.24 μA to 0.62 μA. However, when the sensor was returned to an air environment, the current gradually decreased and eventually returned to its initial value, indicating that DMMP can achieve complete desorption on the silicon nanoribbon surface. The response time and recovery time of the sensor were also calculated, and the device response time and recovery time were approximately 110 s and 965 s, respectively.

[0211] like Figure 12 As shown in Figures b and c, the responsivity significantly increases with increasing DMMP concentration. At the lowest concentration of 20 ppm, the responsivity is 11.5%, while at the highest concentration of 100 ppm, a responsivity of nearly 200% is achieved. Linear fitting at different responsivity levels shows that an approximately linear response (R0) can be observed in the range of 20–100 ppm. 2 =0.978). From the continuous dynamic response-recovery plot, it can be seen that the response time and recovery time performance are relatively consistent for different concentrations of DMMP.

[0212] Furthermore, the sensors from Examples 2 to 6 were placed on the sample stage, and DMMP liquid was delivered to the heating platform using a microsyringe. Their electrical response to 80 ppm DMMP was tested, and the data in the table below were obtained.

[0213]

[0214] As shown in the table above, the gas sensor obtained by using the molecular modification on the surface of a silicon nanoribbon field-effect transistor designed in this application can effectively detect DMMP gas. When in contact with DMMP gas, the current signal increases significantly, exhibiting high responsivity with a response time on the order of minutes.

[0215] To verify the repeatability of the sensor, the sensor of Example 1 was subjected to five consecutive cyclic tests, and the results were obtained. Figure 13 , Figure 13 This is the continuous response-recovery cycle curve of the sensor in Example 1 of Example 5 of this application. (The light background in the figure represents the air atmosphere, and the dark background represents the DMMP atmosphere.)

[0216] like Figure 13 As shown, the electrical signal curves after five cycles of introducing DMMP gas are quite consistent, with small differences in response value, response time, and recovery time, indicating that the sensor has good repeatability.

[0217] To verify the selectivity of the sensor, the response of the sensor in Example 1 to various VOCs and DMMP, including acetone, ethanol, toluene, and dichloromethane, was tested, and the results were obtained. Figure 14 , Figure 14 This is a graph showing the response data of the sensor in Example 1 of Example 5 of this application to 100 ppm DMMP and other VOCs.

[0218] like Figure 14 As shown, compared to other VOCs, the sensor of Example 1 exhibits exceptionally high responsiveness to DMMP, and is almost unresponsive to toluene, dichloromethane, and other similar substances. This sensor can be used for the specific detection of nerve agents.

[0219] Furthermore, by comparing the response curves of the sensors in Example 1 and Comparative Example 3 to 80 ppm DMMP, the following results were obtained. Figure 15 , Figure 15 These are the response curves of the sensors in Example 1 and Comparative Example 3 of this application to 80 ppm DMMP. The inset shows a magnified response curve of the sensor in Comparative Example 3.

[0220] like Figure 15 As shown, the silicon nanoribbon field-effect transistor of Example 1 has better sensitivity and stability than the silicon nanoparticle device of Comparative Example 3.

[0221] This is mainly because silicon nanoparticles have a large specific surface area and a large number of surface dangling bonds, generating a large number of free charge carriers, which greatly affects the electrical properties of the material. Therefore, its electrical properties are closer to those of a conductor. Since there are a large number of free charge carriers, the effect of gas adsorption on conductivity is relatively small, while the adsorption-desorption equilibrium of gas molecules at the interface between silicon nanoparticles will cause current fluctuations.

[0222] Comparative studies show that a continuous crystal structure and fewer surface defects are crucial for silicon-based gas sensors. Silicon nanoribbons possess the conductive pathways of a continuous crystal structure and the favorable surface conditions resulting from mature fabrication processes. Furthermore, their nanoscale thickness ensures that the surface conductivity accounts for a significant proportion of the total conductivity, allowing surface-adsorbed molecules to substantially influence the overall conductivity of the silicon nanoribbons. Therefore, silicon nanoribbons are a preferred material for fabricating silicon-based gas sensors.

Claims

1. A compound for detecting DMMP, characterized in that, It has the structure shown in the following general formula 1; [General Formula 1]: ； In the general formula 1, R1 is selected from , and One of the groups; R2, R3, and R4 each independently represent C1 to C6 groups; L1 and L2 each independently represent C1~C12 groups; R5 is an alkyl or aryl group; Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups may optionally have 0, 1, or more fluorine atoms substituted; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylenephenylene, propylenephenylene, pentylenephenylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

2. A compound for detecting DMMP, characterized in that, It has the structure shown in the following general formula 2; [General Formula 2]: ； In the general formula 2, R2, R3, and R4 each independently represent C1 to C6 groups; L1 and L2 each independently represent C1~C12 groups; N1, N2, N3, N4, and N5 each independently choose either carbon or nitrogen atoms; R6 is selected from one of hydrogen, deuterium, halogen, hydroxyl, mercapto, alkyl, alkoxy, aryl, and aryloxy groups; The C1-C6 groups are selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl; The C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylenephenylene, propylenephenylene, pentylenephenylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

3. The compound according to claim 1, characterized in that, It has the structure shown in the following general formulas 3, 4, 5, 6, 7 or 8; ； ； ； In general formulas 3, 4, 5, 6, 7, and 8, R2, R3, and R4 each independently represent methyl, ethyl, propyl, butyl, pentyl, or hexyl.

4. A method for preparing the compound according to claim 1 or 3, characterized in that, include: The compound is obtained by condensing a first reactant having the following general formula 10 and a second reactant having the following general formula 11 under the action of a catalyst; [General Formula 10]: ； [General Formula 11]: ； In general formulas 10 and 11, R2, R3, and R4 each independently represent C1 to C6 groups; L1 and L2 each independently represent C1~C12 groups; R5 is an alkyl or aryl group; R7 is selected from either amino or carboxyl groups, and when R7 is amino, R8 is selected from either amino or carboxyl groups. One of them, where R7 is a carboxyl group and R8 is an amino group; Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups may optionally have 0, 1, or more fluorine atoms substituted; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

5. The preparation method according to claim 4, characterized in that, The catalyst comprises any one of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide; the molar ratio of the first reactant, the second reactant, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is: (1~5):(1~5):(0.8~1.2):(0.8~1.2).

6. A DMMP sensor, characterized in that, include: A silicon substrate, including a first surface and a second surface disposed opposite to each other; An insulating layer is disposed on the first surface; A first silicon epitaxial layer and a second silicon epitaxial layer are disposed at intervals on the surface of the insulating layer; Multiple silicon nanoribbons are arranged on the surface of the insulating layer, and their two ends are respectively connected to the first silicon epitaxial layer and the second silicon epitaxial layer; The source and drain are respectively disposed on the surface of the first silicon epitaxial layer and the surface of the second silicon epitaxial layer; A gate is disposed on the second surface; The first silicon epitaxial layer, the second silicon epitaxial layer, and the silicon nanoribbon have the same conductivity type. The silicon nanoribbon surface is modified with the compound of claim 1 or 3, wherein the R2, R3, and R4 groups of the compound are substituted so that the compound is covalently connected to the silicon nanoribbon.

7. The DMMP sensor according to claim 6, characterized in that, The compound is arranged in a single layer on the surface of the silicon nanoribbons; The silicon nanoribbon has an extension length of 10~100 μm in the first direction, an extension width of 100nm~10 μm in the second direction, and a thickness of 10~200 nm. The silicon nanoribbons extend along a first direction, and the plurality of silicon nanoribbons are uniformly spaced along a second direction. Wherein, the first direction is the direction from the first silicon epitaxial layer to the second silicon epitaxial layer, and the second direction is perpendicular to the first direction.

8. A method for fabricating a DMMP sensor according to claim 6 or 7, characterized in that, include: A field-effect transistor is provided, the field-effect transistor comprising a silicon substrate, an insulating layer disposed on the surface of the silicon substrate, a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer, and a plurality of silicon nanoribbons disposed on the surface of the insulating layer and connected at both ends to the first silicon epitaxial layer and the second silicon epitaxial layer, respectively. The field-effect transistor was hydroxylated using a piranha solution to obtain a first silicon wafer, wherein the piranha solution included concentrated sulfuric acid and hydrogen peroxide. A source and a drain are fabricated on the first silicon wafer to obtain a second silicon wafer; A compound having general formula 1 is grafted onto the surface of silicon nanoribbons of the second silicon wafer to obtain a third silicon wafer; A gate is fabricated on the third silicon wafer to obtain the DMMP sensor.

9. The preparation method according to claim 8, characterized in that, The step of grafting a compound having general formula 1 onto the surface of a silicon nanoribbon of the second silicon wafer includes: The second silicon wafer is modified with a first reactant having the following general formula 10; A condensation reaction is carried out between a second reactant having the following general formula 11 and a second silicon wafer modified with the first reactant under the action of a catalyst. [General Formula 10]: ； [General Formula 11]: ； In general formulas 10 and 11, R2, R3, and R4 each independently represent C1 to C6 groups; L1 and L2 each independently represent C1~C12 groups; R5 is an alkyl or aryl group; R7 is selected from either amino or carboxyl groups, and when R7 is amino, R8 is selected from either amino or carboxyl groups. One of them, where R7 is a carboxyl group and R8 is an amino group; Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups may optionally have 0, 1, or more fluorine atoms substituted; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

10. The preparation method according to claim 9, characterized in that, The catalyst comprises either 1-ethyl-(3-dimethylaminopropyl)carbodiimide or N-hydroxysuccinimide; The specific steps for modifying the second silicon wafer using the first reactant are as follows: dissolving the first reactant in a solvent to obtain a first immersion solution; immersing the second silicon wafer in the first immersion solution, then removing it, cleaning it, and drying it; wherein the immersion time is 0.5~5 h, and the volume fraction of the first reactant in the first immersion solution is 1~10%; The specific steps of using the second reactant and the second silicon wafer modified with the first reactant to carry out a condensation reaction under the action of a catalyst are as follows: the second reactant is dissolved in a solvent, and then mixed with an N-hydroxysuccinimide solution and a 1-ethyl-(3-dimethylaminopropyl)carbodiimide solution to obtain a second soaking solution; the second silicon wafer modified with the first reactant is soaked in the second soaking solution, then washed and dried; wherein, the concentration of N-hydroxysuccinimide in the second soaking solution is 0.01~0.05 mol / L, the concentration of 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 0.01~0.05 mol / L, the concentration of the second reactant is 0.02~0.5 mol / L, and the soaking time is 2~5 h; Before the step of performing a condensation reaction between the second reactant and the second silicon wafer modified with the first reactant under the action of a catalyst, the method further includes: immersing the second silicon wafer modified with the first reactant in water, then removing it and drying it; wherein the immersion time is 3 to 10 hours.

11. The preparation method according to claim 8, characterized in that, The step of grafting a compound having general formula 1 onto the surface of silicon nanoribbons of the second silicon wafer includes: dissolving the compound in a solvent to obtain a third soaking solution; immersing the second silicon wafer in the third soaking solution, then removing it and drying it; wherein the concentration of the compound in the third soaking solution is 0.02~0.5 mol / L, and the soaking time is 0.5-5 h; The piranha solution was obtained by mixing 30% hydrogen peroxide and 98% concentrated sulfuric acid in a volume ratio of 3:(7~9); The hydroxylation treatment specifically involves: placing the field-effect transistor in a container, pouring the piranha solution into the container, heating it in a water bath, then removing the field-effect transistor, cleaning it, and drying it; wherein the temperature of the water bath is 70~95 ℃ and the time is 10~60 min.

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