Laser-induced graphene gas sensor and preparation method thereof
By using a three-dimensional polyimide microsphere array and laser etching to generate a graphene layer in a laser-induced graphene gas sensor, the problem of low detection sensitivity is solved, high-sensitivity and low-power gas detection is achieved, and the application scenarios of gas sensors are expanded.
Patent Information
- Application Number
- CN202510795511.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-09-16
AI Technical Summary
The detection sensitivity of existing laser-induced graphene gas sensors is low and cannot meet the needs of practical applications.
A three-dimensional polyimide microsphere array is used to replace the traditional two-dimensional polyimide film. A graphene layer is generated on it by laser etching to form a LIG gas-sensitive layer, and electrodes are prepared on the edge to form a laser-induced graphene gas sensor.
The specific surface area of the sensor is significantly improved, the gas detection sensitivity is enhanced, the power consumption is reduced, the safety risks caused by high-temperature operation are reduced, and the cost is reduced.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of gas sensing technology, and in particular to a laser-induced graphene gas sensor and a preparation method thereof. Background Art
[0002] A gas sensor is a device used to detect the concentration of a specific gas and has important applications in environmental monitoring, industrial production, medical health and other fields. Based on different sensing principles, gas sensors are mainly divided into three categories: electrochemical, semiconductor and spectral sensors. In comparison, electrochemical gas sensors have problems such as the need for regular calibration and a short service life, which limit their actual monitoring applications. Although spectral gas sensors have high accuracy, they are usually expensive and have complex systems, which are not conducive to large-scale promotion and application. Semiconductor gas sensors are currently the most commonly used type of gas sensor, with advantages such as miniaturization, high cost performance and easy integration. However, they usually need to operate at higher operating temperatures (for example, above 200°C), consume a lot of energy, and high-temperature operation may cause gas explosions, posing safety risks.
[0003] In recent years, gas sensors based on novel nanomaterials have garnered widespread attention. Graphene, a key nanomaterial, possesses a two-dimensional planar structure and high electron mobility, making it an excellent gas-sensing material. In particular, the recent development of simple laser etching methods has enabled the rapid and cost-effective fabrication of graphene, leading to the rapid development of gas sensors based on laser-induced graphene (LIG). In LIG gas sensors, LIG is typically fabricated on a two-dimensional polyimide film using a laser. When LIG interacts with a gas, the adsorption of the gas on the LIG surface causes changes in the LIG's electrical properties (such as carrier concentration), enabling gas concentration measurement. To date, LIG-based sensors have been used to detect a variety of gases, including nitrogen dioxide (NO2) and ammonia (NH3). LIG gas sensors are simple to fabricate, low-cost, and operate at room temperature, offering significant potential for widespread application. However, improving the detection sensitivity of LIG gas sensors is crucial for their practical application and has become a key research topic. Summary of the Invention
[0004] The purpose of this application is to provide a laser-induced graphene gas sensor and a preparation method thereof, which can improve the detection sensitivity of the laser-induced graphene gas sensor.
[0005] To achieve the above objectives, this application provides the following solutions:
[0006] In a first aspect, the present application provides a laser-induced graphene gas sensor comprising a substrate, a polyimide microsphere array, a LIG gas-sensitive layer, and electrodes; the polyimide microsphere array is a single-layer structure composed of a plurality of arranged polyimide microspheres; the polyimide microsphere array is disposed on the surface of the substrate; the LIG gas-sensitive layer is configured to interact with a gas to be measured and convert the gas concentration of the gas to be measured into a resistance characteristic; the electrodes are connected to a measuring component, which is configured to measure an electrical parameter converted from the gas concentration of the gas to be measured.
[0007] Optionally, the LIG gas-sensitive layer is a three-dimensional wrinkled structure formed by carbonizing some polyimide microspheres in the polyimide microsphere array to generate graphene.
[0008] Optionally, the substrate is made of a hard material or a flexible material; the hard material is silicon or silicon dioxide; the flexible material is polydimethylsiloxane, polyethylene terephthalate or polyvinyl alcohol.
[0009] Optionally, the polyimide microspheres have a diameter ranging from 1 μm to 20 μm.
[0010] Optionally, the LIG gas sensing layer has a thickness in the range of 1-20 μm.
[0011] Optionally, the material of the electrode is gold or copper.
[0012] In a second aspect, the present application provides a method for preparing a laser-induced graphene gas sensor, comprising:
[0013] Arranging polyimide microspheres on the surface of a substrate to form a polyimide microsphere array;
[0014] Carbonizing some polyimide microspheres in the polyimide microsphere array to generate graphene, thereby forming a LIG gas-sensitive layer;
[0015] Electrodes are prepared at the edge of the LIG gas-sensitive layer; the substrate, polyimide microsphere array, LIG gas-sensitive layer and electrodes constitute a laser-induced graphene gas sensor.
[0016] Optionally, some of the polyimide microspheres in the polyimide microsphere array are carbonized to generate graphene to form the LIG gas-sensitive layer, specifically comprising: scanning the surface of the polyimide microsphere array using a laser etching method, and carbonizing some of the polyimide microspheres in the polyimide microsphere array to generate graphene to form the LIG gas-sensitive layer.
[0017] Optionally, the laser used in the laser etching method is a carbon dioxide laser, a blue light laser or an ultraviolet laser.
[0018] Optionally, arranging the polyimide microspheres on the surface of the substrate to form a polyimide microsphere array specifically includes: utilizing an interfacial self-assembly method to arrange the polyimide microspheres on the surface of the substrate to form a polyimide microsphere array.
[0019] According to the specific embodiments provided in this application, this application discloses the following technical effects:
[0020] This application provides a laser-induced graphene gas sensor and its preparation method. The laser-induced graphene gas sensor includes a substrate, a polyimide microsphere array, a LIG gas-sensing layer, and electrodes. The polyimide microsphere array is a single-layer structure composed of a plurality of arranged polyimide microspheres. The polyimide microsphere array is placed on the substrate surface. The LIG gas-sensing layer is used to interact with the gas to be measured, converting the gas concentration of the measured gas into a resistance characteristic. The electrodes are connected to a measuring component, which measures the electrical parameter converted from the gas concentration of the measured gas. This application utilizes a three-dimensional polyimide microsphere array instead of a traditional two-dimensional polyimide film, significantly increasing the specific surface area of the LIG material and thereby improving its gas-sensing performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0022] Figure 1 This is a schematic structural diagram of a laser-induced graphene gas sensor provided in Example 1 of the present application.
[0023] Figure 2 Schematic diagram showing the comparison of the response behaviors of LIG gas sensors based on three-dimensional polyimide microsphere arrays and two-dimensional polyimide films to nitrogen dioxide gas provided in Example 1 of the present application.
[0024] Figure 3 Schematic diagram of the response behavior of the polyimide microsphere array LIG gas sensor with a polyimide microsphere diameter of 5 μm provided in Example 1 of the present application to different concentrations of nitrogen dioxide gas.
[0025] Figure 4 Schematic diagram of the response behavior of the polyimide microsphere array LIG gas sensor with a polyimide microsphere diameter of 2 μm provided in Example 1 of the present application to different concentrations of nitrogen dioxide gas.
[0026] Figure 5 A schematic flow chart of the method for preparing a laser-induced graphene gas sensor provided in Example 2 of the present application.
[0027] Reference numerals:
[0028] Substrate—1, polyimide microsphere array—2, LIG gas-sensitive layer—3, electrode—4. DETAILED DESCRIPTION
[0029] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0031] Example 1.
[0032] like Figure 1 As shown, this embodiment provides a laser-induced graphene gas sensor, including a substrate 1, a polyimide microsphere array 2, a LIG gas-sensitive layer 3 and an electrode 4.
[0033] Substrate 1 supports the device; polyimide microsphere array 2 provides a three-dimensional micro-nanostructure; LIG gas-sensing layer 3 interacts with the gas being measured, converting its concentration into a resistance characteristic; and electrode 4 connects to an external drive circuit or instrument for measurement. The external drive circuit or instrument, such as a digital multimeter, measures the resistance corresponding to the gas being measured and determines its concentration based on the measured resistance.
[0034] The polyimide microsphere array 2 is a single-layer structure composed of a plurality of polyimide microspheres. Specifically, the polyimide microsphere array 2 is a single-layer micro-nanostructure prepared by self-assembly of polyimide microspheres. The diameter of the polyimide microspheres ranges from 1 μm to 20 μm. The polyimide microsphere array 2 is placed on the surface of the substrate 1.
[0035] The LIG gas-sensitive layer 3 is used to interact with the gas to be measured and convert the gas concentration of the gas to be measured into resistance characteristics; the electrode 4 is connected to the measuring component, which is used to measure the electrical parameters converted from the gas concentration of the gas to be measured.
[0036] The LIG gas-sensing layer 3 is a three-dimensional corrugated structure formed by carbonizing some of the polyimide microspheres in the polyimide microsphere array 2 to generate graphene using a laser etching method. The LIG gas-sensing layer 3 is prepared by laser etching, that is, scanning the polyimide microsphere array 2 with a high-energy laser according to a preset pattern to form a three-dimensional corrugated graphene sensitive layer. Figure 1 The rectangular pattern in FIG is only an example and is not intended to be limiting. The laser is typically a carbon dioxide laser, a blue laser, or an ultraviolet laser. The thickness of the LIG gas-sensitive layer 3 is in the range of 1-20 μm.
[0037] The material of the substrate 1 can be a hard material such as silicon or silicon dioxide, or a flexible material such as polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyvinyl alcohol (PVA), etc.
[0038] The electrode 4 is usually made of conductive materials such as gold and copper.
[0039] Two examples are given below to verify the performance of the laser-induced graphene gas sensor provided in this application.
[0040] Example 1: A glass substrate is used as the substrate 1 of the sensor. Polyimide microspheres with a diameter of 5 μm are selected, and a close-packed single-layer polyimide microsphere array 2 is formed on the surface of the glass substrate using the interface self-assembly method. The surface of the polyimide microsphere array 2 is scanned using the laser etching method to generate a graphene layer, namely the LIG gas sensitive layer 3. A carbon dioxide (CO2) laser is used in the experiment. The typical laser etching parameters are: laser power 8W, scanning speed 200 mm / s. Finally, a gold electrode is prepared on the edge of the graphene structure (LIG gas sensitive layer 3) to obtain the overall structure of the LIG gas sensor (as shown in the attached figure). Figure 1 As shown). Taking nitrogen dioxide (NO2) gas as an example, Figure 2 The responses of a three-dimensional polyimide microsphere array LIG gas sensor to 1 ppm NO₂ gas are compared with those of a conventional two-dimensional polyimide thin film LIG gas sensor. The horizontal axis represents time (in seconds / s) and the vertical axis represents ΔR / R₀ (in percent), where ΔR / R₀ represents the ratio of the change in resistance ΔR to the initial resistance R₀. The microsphere LIG sensor in the figure refers to the laser-induced graphene gas sensor proposed in this application, while the thin film LIG sensor refers to a laser-induced graphene gas sensor fabricated using polyimide film. The laser-etched LIG parameters were identical in both cases. The results show that, compared to the two-dimensional polyimide film structure, the three-dimensional polyimide microsphere array 2 exhibits superior gas-sensing properties due to its larger specific surface area, with its resistive response to NO₂ increasing by approximately 60%.
[0041] Example 2: The laser-induced graphene gas sensor proposed in this application can regulate the performance of the LIG gas sensor by changing the diameter of the polyimide microspheres and the laser etching conditions. Figure 3 and Figure 4The response characteristics of LIG gas sensors fabricated with polyimide microspheres of 5μm and 2μm in diameter to different NO₂ gas concentrations at room temperature are presented. As the polyimide microsphere diameter decreases, the specific surface area of the laser-induced graphene gas sensor increases, facilitating gas adsorption and gas-LIG interaction. This results in a larger resistance change and improved gas sensing performance.
[0042] The laser-induced graphene gas sensor provided in this application is a micro-nano composite gas sensor based on laser-induced graphene, specifically a laser-induced graphene gas sensor enhanced by a polyimide microsphere array 2. To address the low sensitivity issues currently faced by LIG gas sensors, this application proposes a novel three-dimensional micro-nanostructured LIG gas sensor. This sensor utilizes a three-dimensional polyimide microsphere array 2 in place of the traditional two-dimensional polyimide film, significantly increasing the specific surface area of the LIG material and thereby improving its gas-sensing performance.
[0043] This application proposes a laser-induced graphene gas sensor based on a polyimide microsphere array 2, which provides a new approach for the development of low-cost, high-performance gas sensors and expands the practical application scenarios of gas sensors. It has the following significant technical advantages:
[0044] 1. Using a polyimide microsphere array 2 as a template, the micromorphology of the LIG sensitive layer 3 is manipulated to significantly increase the active sites for gas adsorption, thereby improving gas detection sensitivity.
[0045] 2. By synergistically optimizing the size of polyimide microspheres (1-20 μm) and laser parameters (power, scanning speed), a balance between graphene defect density and conductivity can be achieved. The optimal laser etching parameters will vary at different microsphere sizes, and specific parameter optimization usually requires experimental optimization.
[0046] 3. The integrated LIG preparation process based on laser etching does not require a transfer step, reducing costs; it can also achieve the preparation of LIG gas-sensing structures with arbitrary patterns.
[0047] 4. This type of LIG gas sensor does not require high temperature to operate, effectively reducing the power consumption of the device and reducing the risk of gas explosion in the detection environment.
[0048] Example 2.
[0049] This embodiment provides a method for preparing a laser-induced graphene gas sensor. The solution to the problem provided by this method is similar to the solution described in the aforementioned laser-induced graphene gas sensor. Therefore, the specific limitations in the following preparation method embodiment can be referred to the above limitations of the laser-induced graphene gas sensor and will not be repeated here.
[0050] like Figure 5 As shown, the present embodiment provides a method for preparing a laser-induced graphene gas sensor, comprising the following steps S1 to S3:
[0051] Step S1: Arranging polyimide microspheres on the surface of a substrate to form a polyimide microsphere array;
[0052] Step S2: carbonizing some of the polyimide microspheres in the polyimide microsphere array to generate graphene, thereby forming a LIG gas-sensitive layer;
[0053] Step S3: preparing electrodes at the edge of the LIG gas-sensitive layer; the substrate, polyimide microsphere array, LIG gas-sensitive layer and electrodes constitute a laser-induced graphene gas sensor.
[0054] As an optional embodiment, some of the polyimide microspheres in the polyimide microsphere array are carbonized to generate graphene to form a LIG gas-sensitive layer, specifically comprising: scanning the surface of the polyimide microsphere array using a laser etching method, and carbonizing some of the polyimide microspheres in the polyimide microsphere array to generate graphene to form a LIG gas-sensitive layer.
[0055] In this embodiment, the laser used in the laser etching method can be a carbon dioxide laser, a blue light laser, or an ultraviolet laser.
[0056] Arranging polyimide microspheres on the surface of a substrate to form a polyimide microsphere array specifically includes: utilizing an interface self-assembly method to arrange polyimide microspheres on the surface of a substrate to form a polyimide microsphere array.
[0057] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0058] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.
Claims
1. A laser-induced graphene gas sensor, characterized in that: The laser-induced graphene gas sensor includes a substrate, a polyimide microsphere array, a LIG gas-sensitive layer, and electrodes. The polyimide microsphere array is a single-layer structure composed of a plurality of arranged polyimide microspheres. The polyimide microsphere array is placed on the surface of the substrate. The LIG gas-sensitive layer is used to interact with the gas to be measured and convert the gas concentration of the gas to be measured into a resistance characteristic. The electrodes are connected to a measuring component, which is used to measure the electrical parameter converted from the gas concentration of the gas to be measured.
2. The laser-induced graphene gas sensor according to claim 1, characterized in that: The LIG gas-sensitive layer is a three-dimensional wrinkled structure formed by carbonizing some polyimide microspheres in the polyimide microsphere array to generate graphene.
3. The laser-induced graphene gas sensor according to claim 1, characterized in that: The substrate is made of a hard material or a flexible material; the hard material is silicon or silicon dioxide; the flexible material is polydimethylsiloxane, polyethylene terephthalate or polyvinyl alcohol.
4. The laser-induced graphene gas sensor according to claim 1, characterized in that: The diameter of polyimide microspheres ranges from 1 μm to 20 μm.
5. The laser-induced graphene gas sensor according to claim 1, characterized in that: The thickness of the LIG gas-sensitive layer ranges from 1 to 20 μm.
6. The laser-induced graphene gas sensor according to claim 1, characterized in that: The material of the electrodes is gold or copper.
7. A method for preparing a laser-induced graphene gas sensor according to any one of claims 1 to 6, characterized in that: The preparation method of the laser-induced graphene gas sensor comprises: Arranging polyimide microspheres on the surface of a substrate to form a polyimide microsphere array; Carbonizing some polyimide microspheres in the polyimide microsphere array to generate graphene, thereby forming a LIG gas-sensitive layer; Electrodes are prepared at the edge of the LIG gas-sensitive layer; the substrate, polyimide microsphere array, LIG gas-sensitive layer and electrodes constitute a laser-induced graphene gas sensor.
8. The method for preparing a laser-induced graphene gas sensor according to claim 7, wherein: Carbonizing some polyimide microspheres in the polyimide microsphere array to generate graphene to form a LIG gas sensing layer, specifically comprising: The surface of the polyimide microsphere array is scanned by laser etching, and some of the polyimide microspheres in the polyimide microsphere array are carbonized to generate graphene, forming a LIG gas-sensitive layer.
9. The method for preparing a laser-induced graphene gas sensor according to claim 8, wherein: The laser used in the laser etching method is a carbon dioxide laser, a blue light laser or an ultraviolet laser.
10. The method for preparing a laser-induced graphene gas sensor according to claim 7, wherein: Arranging polyimide microspheres on the surface of a substrate to form a polyimide microsphere array specifically includes: The polyimide microspheres are arranged on the surface of the substrate by using an interface self-assembly method to form a polyimide microsphere array.