阅读说明：本技术 一种用于二氧化氮检测的3d柔性二硫化锡/石墨烯气体传感器的制备方法 (Preparation method of 3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection ) 是由 吴进 奚亚男 胡淑锦 于 2019-10-31 设计创作，主要内容包括：本发明提供了一种用于二氧化氮检测的3D柔性二硫化锡/石墨烯(SnS<Sub>2</Sub>/RGO)气体传感器的制备方法。本发明在3D结构的石墨烯表面修饰SnS<Sub>2</Sub>,并将SnS<Sub>2</Sub>/RGO异质结构修饰在柔性LCP基材表面,制成可于常温环境检测二氧化氮的柔性气体传感器。本发明制备的传感器具有高灵敏度、高选择性、低检出限的优秀性能,灵敏度为6.1ppm<Sup>-1</Sup>,检出限为8.7ppb,可应用于可穿戴设备领域。(The invention provides 3D flexible tin disulfide/graphene (SnS) for detecting nitrogen dioxide 2 Method for producing an RGO) gas sensor. The method modifies SnS on the surface of graphene with a 3D structure 2 And SnS 2 the/RGO heterostructure is modified on the surface of the flexible LCP substrate to prepare the flexible gas sensor capable of detecting nitrogen dioxide in a normal temperature environment. The sensor prepared by the invention has excellent performances of high sensitivity, high selectivity and low detection limit, and the sensitivity is 6.1ppm ‑1 The detection limit is 8.7ppb, and the method can be applied to the field of wearable equipment.)

1. A3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection is characterized by comprising a flexible substrate and an electrode layer, wherein the flexible substrate is modified on the surface of the electrode layer, and the electrode layer comprises 3D SnS₂a/RGO heterostructure layer.

2. The 3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection as claimed in claim 1, wherein said flexible substrate material is LCP.

3. The preparation method of the 3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection according to claim 1, comprising the following steps:

S1、3D SnS₂preparation of/RGO: under the condition of continuous stirring, adding thioacetamide and stannic chloride pentahydrate into graphene oxide solution, ultrasonically dissolving the obtained mixture, transferring the mixture into a reaction kettle for hydrothermal reaction, centrifuging and washing the obtained product to obtain solid SnS₂an/RGO product;

S2、SnS₂preparation of/RGO gas sensor: bonding a double-sided copper-clad LCP film on a silicon wafer by using photoresist, removing a bare copper layer on the surface of the LCP film in an etching mode, spin-coating a photoresist layer on the surface of the LCP film, sputtering a Cr/Au layer, processing an interdigital electrode on an LCP substrate by adopting a stripping technology, and processing the solid SnS prepared in the step S1₂and/RGO is dispersed in deionized water to prepare water dispersion, the water dispersion is deposited on the surface of the interdigital electrode of the LCP substrate, and the gas sensor is prepared after air drying.

4. The method for preparing the 3D flexible tin disulfide/graphene gas sensor for detecting nitrogen dioxide, prepared according to the method of claim 3, wherein in the step S1, the mass ratio of thioacetamide, tin chloride pentahydrate and graphene oxide is 30: 35: 4.

5. The method for preparing the 3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection according to the method of claim 3, wherein in the step S1, the hydrothermal reaction condition is heating at 180 ℃ for 10-12 h.

6. The method for preparing the 3D flexible tin disulfide/graphene gas sensor for detecting nitrogen dioxide, which is prepared according to the method of claim 3, wherein in the step S2, the thickness of the silicon wafer is 300 μm.

7. The method for preparing a 3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection according to claim 3, wherein in step S2, the spin-on photoresist has a thickness of 5 μm.

8. The method for preparing the 3D flexible tin disulfide/graphene gas sensor for detecting nitrogen dioxide, which is prepared according to the method of claim 3, wherein in the step S2, the thickness of the sputtered Cr layer is 8nm, and the thickness of the Au layer is 280 nm.

9. The method for preparing a 3D flexible tin disulfide/graphene gas sensor for nitrogen dioxide detection according to the method of claim 3, wherein in the step S2, the concentration of the aqueous dispersion is 2.0 mg/mL.

Technical Field

The invention belongs to the technical field of gas sensors, and relates to 3D flexible tin disulfide/graphene (SnS)₂an/RGO) gas sensor and a method for producing the same.

Background

With the rapid development of industry and agriculture, the emission of toxic and flammable gases, such as nitrogen oxides, sulfur oxides, and carbon oxides, is a serious hazard to environmental health. Wherein nitrogen dioxide (NO)₂) Can cause respiratory and cardiovascular diseases, can also cause acid rain and photochemical smog, and is considered as a typical air pollutant, the international standardNO determination₂The annual safe concentration threshold of (c) is 53 ppb.

NO₂And is also widely used in agriculture, medicine, military and mining. Such as synthetic manufacture of explosives and fertilizers and as biomarkers for diagnosis of lung and gastrointestinal diseases, etc., and thus, a NO having high sensitivity, high specificity, low detection limit₂The gas sensor is urgently needed by the current environmental monitoring and medical diagnosis industry and is beneficial to realizing NO₂High reliability and real-time monitoring.

The unique two-dimensional conjugated structure of the graphene has ultrahigh carrier mobility, and can effectively increase the carrier transmission speed and the conduction efficiency of the composite material, thereby greatly improving the response rate, shortening the response recovery time, reducing the working temperature of the sensor, and being a high-performance material for preparing the gas detection sensor.

The traditional gas sensor made of metal oxide requires high-temperature detection and oxygen environment, the gas sensor made of graphene composite material can realize detection at room temperature, energy consumption can be obviously reduced, and the graphene composite material is suitable for daily life detection requirements. The graphene can be self-assembled into a 3D porous structure composite material, and can be used for super capacitors, adsorption materials, sensors and the like. Compared with a 2D structure, the graphene with the 3D structure can provide more specific surface area and reaction sites, so that the detection sensitivity is greatly improved.

For NO₂For gas-sensitive detection, a graphene-based gas-sensitive sensor has poor selectivity, which limits the practicability. Tin disulfide (SnS)₂) Can be used alone as NO₂Use of gas-sensitive materials for NO₂The molecule has strong specific adsorption capacity, the detection limit can be lower than 1ppm, but the NO detection at room temperature can not be realized₂Limit based on SnS₂The gas sensor of (1) is applied in general environment. Thus modifying NO on graphene₂Sensitive SnS₂Can combine the performance advantages of the two, and prepare NO which has high sensitivity, high selectivity, high reliability and can be used at normal temperature₂A gas sensor.

Disclosure of Invention

The object of the present invention is to solve the need for NO which is highly sensitive, highly selective, highly reliable and usable at ordinary temperatures₂Problem of gas sensor, and to provide a method for NO₂Detected 3D flexible tin disulfide/graphene (SnS)₂Method for producing an RGO) gas sensor.

The gas sensor prepared by the invention comprises a flexible substrate and an electrode layer, wherein the surface of the flexible substrate is modified with the electrode layer, and the electrode layer comprises 3D SnS₂a/RGO heterostructure layer.

The present invention uses LCP as the flexible substrate material.

The invention further aims to provide a preparation method of the 3D flexible tin disulfide/graphene gas sensor for detecting nitrogen dioxide.

The method specifically comprises the following steps:

S1、3D SnS₂preparation of/RGO: under the condition of continuous stirring, adding thioacetamide and stannic chloride pentahydrate into graphene oxide solution, ultrasonically dissolving the obtained mixture, transferring the mixture into a reaction kettle for hydrothermal reaction, centrifuging and washing the obtained product to obtain solid SnS₂an/RGO product;

S2、SnS₂preparation of/RGO gas sensor: bonding a double-sided copper-clad LCP film on a silicon wafer by using photoresist, removing a bare copper layer on the surface of the LCP film in an etching mode, spin-coating a photoresist layer on the surface of the LCP film, sputtering a Cr/Au layer, processing an interdigital electrode on an LCP substrate by adopting a stripping technology, and processing the solid SnS prepared in the step S1₂and/RGO is dispersed in deionized water to prepare water dispersion, the water dispersion is deposited on the surface of the interdigital electrode of the LCP substrate, and the gas sensor is prepared after air drying.

3D SnS prepared by the invention₂Detection performance and SnS of/RGO sensor₂Compared with a sensor, the sensor is higher by three orders of magnitude, and SnS is modified on 3D RGO₂The method greatly reduces the resistance value of the device and improves the overall detection performance of the sensor.

Further, in the step S1, the mass ratio of thioacetamide, tin chloride pentahydrate and graphene oxide is 30: 35: 4.

Further, in the step S1, the hydrothermal reaction is performed under a condition of heating at 180 ℃ for 10-12 hours.

The invention uses fine processing technology to process the interdigital electrode array on the flexible LCP substrate and leads the 3D SnS₂depositing/RGO structure on the surface of base material, repeatedly bending LCP substrate, modifying electrode and SnS₂the/RGO structure does not generate stripping phenomenon, and the modified SnS is shown₂the/RGO structure has strong adhesion, and the sensor can be used for wearable equipment and flexible devices.

Further, in the step S2, the silicon wafer has a thickness of 300 μm.

Further, in step S2, the spin-on photoresist has a thickness of 5 μm.

Further, in step S2, the thickness of the sputtered Cr layer is 8nm, and the thickness of the Au layer is 280 nm.

Further, in the step S2, the concentration of the aqueous dispersion is 2.0 mg/mL.

The 3D SnS prepared by the method is subjected to SEM, Raman spectrum, XPS and the like₂the/RGO is characterized.

As shown in attached figure 2, 3D SnS prepared by the invention₂SEM picture of/RGO. As can be seen in the figure, SnS prepared by the invention₂the/RGO structure has a porous structure, the size of the pores ranges from hundreds of nanometers to several micrometers, and NO is facilitated₂Diffusion and adsorption of molecules. After the hydrothermal reaction, the hydrophilic graphene oxide is deoxidized to graphene and restores a conjugated structure due to its hydrophobic interaction and

the interaction forms a 3D porous structure.

As shown in attached figure 3, 3D SnS prepared by the invention₂Raman spectrum of/RGO. As can be seen in the figure, SnS₂Two typical peaks appear on Raman spectra of/RGO and GO (graphene oxide), and are respectively located at 1354cm^-1D band and 1590cm^-1The G band, the D band and the G band correspond to the disorder and the first-order scattering of the graphene 2D mode respectively, I_D：I_GFrom 0.90 liter of GO to SnS₂1.17 of/RGO, which shows that the defect sites on the surface of the graphene can be used as NO when the defect sites on the graphene are increased after the hydrothermal reaction₂Is available to the active adsorption sites of (1), contributes NO₂Sensitivity of detection is improved, and in SnS₂The Raman spectrum of the/RGO is observed to be at 311cm^-1The peak is not observed on a GO spectrogram, and the SnS on the surface of the graphene is verified₂Is performed.

As shown in attached figure 4, 3D SnS prepared by the invention₂XPS profile of/RGO. As can be seen in the figure, SnS₂The composition of/RGO was high C (75.18% at%), small amounts of O (16.15% at%), Sn (2.48% at%) and S (6.19% at%), while that of GO was C (65.5% at%) and O (34.5% at%).

For the 3D SnS prepared by the invention₂NO with/RGO gas sensor₂And testing the gas detection performance.

As shown in FIG. 5, SnS prepared for the invention of example 1₂/RGO and conventional SnS₂And an RGO (graphene) gas sensor for 0.5-8 ppm NO at normal temperature₂Response curve of gas. As can be seen in the figure, SnS₂Response data of/RGO sensor and RGO sensor with NO₂Increase in gas concentration, SnS₂/RGO sensor and RGO sensor for 8ppm NO₂The change in the gas response rates were 49.5% and 2.2%, respectively, and it can be concluded that SnS was modified on RGO₂Then, SnS prepared by the invention₂/RGO gas sensor for NO₂The response performance of the gas is 22.6 times that of the graphene sensor.

As shown in FIG. 6, SnS prepared for the invention of example 1₂the/RGO gas sensor can measure 0-400 ppb NO at normal temperature₂Response curve of gas. This shows that the SnS prepared by the invention₂the/RGO gas sensor has the function of detecting NO with extremely low concentration₂Gas capability, which graphene gas sensors do not have.

As shown in FIG. 7, SnS prepared for the invention of example 1₂/RGO gas sensor and traditional SnS₂And the RGO gas sensor is used for detecting 0-8 ppm NO at normal temperature₂Linear fit curve for gas continuous test. This shows that the SnS prepared by the invention₂the/RGO gas sensor possesses the same NO₂The response performance of the gas can be calculated to obtain SnS₂Sensitivity of the/RGO gas sensor is 6.1ppm^-1The detection limit is 8.7ppb, which is several orders of magnitude lower than that of graphene sensors, and the graphene sensor has the characteristics of high sensitivity and low detection limit.

As shown in FIG. 8, SnS prepared for the invention of example 1₂RGO gas sensor for 2ppm NO₂And (5) testing the repeatability of the gas. It can be seen that after repeating three test cycles, the response rate change is substantially consistent and is 14.3%, and the sensor response signal can be rapidly recovered in a short time, which indicates that the SnS prepared by the invention₂the/RGO gas sensor has good repeatability and reversibility.

As shown in FIG. 9, SnS prepared for the invention of example 1₂Bending test of the/RGO gas sensor. As can be seen in the figure, the response rate of the flexible sensor is basically not changed after the flexible sensor is bent by 120 degrees, which shows that the SnS prepared by the invention has no change under the condition of mechanical deformation₂The detection performance of the/RGO gas sensor is not affected, and the method can be applied to the fields of wearable equipment, electronic skin and the like.

As shown in FIG. 10, SnS prepared for the invention of example 1₂Anti-interference test of/RGO gas sensor. It can be seen that for common interfering gaseous species, e.g. 50ppm NH₃、1000ppm CO₂Saturated VOC vapor, etc., sensor pair 8ppm NO₂The gas response is more than 15 times higher than that of the interference gas, which shows that the SnS prepared by the invention₂the/RGO gas sensor has good selectivity and anti-interference performance.

The method modifies SnS on the surface of graphene with a 3D structure₂Is NO₂Gas molecules provide additional active sites and charge transfer paths while SnS₂The nano/micron pores on the 3D structure of/RGO are also NO₂Gas molecules provide more charge transfer paths, whereas SnS₂By forming a hetero-phase with RGOStructure promoting electron transfer from RGO to NO₂Gas molecules are transferred, so that energy consumption is reduced, and sensitivity is improved.

The invention prepares 3D SnS on a flexible LCP substrate₂the/RGO heterostructure can keep high sensitivity and high reliability under the condition of high bending and can realize NO treatment under the normal temperature condition₂High sensitivity and high selectivity detection.

The invention has the beneficial effects that:

(1) the invention provides a flexible and feasible low-cost 3D SnS₂The preparation method of the/RGO gas sensor has the advantages of high sensitivity, high selectivity and low detection limit.

(2) SnS prepared by the invention₂the/RGO gas sensor can carry out NO at normal temperature₂Detection of gas avoids conventional NO₂The gas sensor needs high temperature detection environment, can be used for daily life, and has wider application range.

(3) SnS prepared by the invention₂the/RGO gas sensor adopts a flexible base material, can be bent, does not influence the detection performance, and can be applied to new fields such as wearable equipment and electronic skin.

Drawings

The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be obtained on the basis of the following drawings without inventive effort.

FIG. 1 shows SnS prepared by the present invention₂A real object diagram of the/RGO gas sensor;

FIG. 2 shows SnS prepared by the present invention₂SEM picture of/RGO;

FIG. 3 shows SnS prepared by the present invention₂Raman spectrum of/RGO;

FIG. 4 shows SnS prepared by the present invention₂XPS profile of/RGO;

FIG. 5 shows SnS prepared in example 1 of the present invention₂/RGO and SnS₂And the RGO gas sensor is used for detecting 0.5-8 ppm NO at normal temperature₂The response curve of the gas;

FIG. 6 shows SnS prepared in example 1 of the present invention₂the/RGO gas sensor can measure 50-400 ppb NO at normal temperature₂The response curve of the gas;

FIG. 7 shows SnS prepared in example 1 of the present invention₂/RGO gas sensor and SnS₂And the RGO gas sensor is used for detecting 0-8 ppm NO at normal temperature₂A linear fit curve for gas continuous testing;

FIG. 8 shows SnS prepared in example 1 of the present invention₂RGO gas sensor for 2ppm NO₂Testing the repeatability of the gas;

FIG. 9 shows SnS prepared in example 1 of the present invention₂Bending test of the/RGO gas sensor;

FIG. 10 shows SnS prepared in example 1 of the present invention₂Anti-interference test of/RGO gas sensor.

Detailed Description

In order that the objects, aspects and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the following detailed description and the accompanying drawings.