High-sensitivity humidity sensor based on inverse opal structure

Abstract

The utility model relates to a high-sensitivity humidity sensor based on an inverse opal structure, and belongs to the field of humidity sensors, the high-sensitivity humidity sensor comprises an insulating substrate, a plurality of strip-shaped grooves are horizontally formed in the upper surface of the insulating substrate, the plurality of strip-shaped grooves are arranged in parallel at intervals, each strip-shaped groove is strip-shaped, and two ends of each strip-shaped groove extend to the edge of the insulating substrate; a strip-shaped groove is formed in the substrate, a first humidity-sensitive film is attached to the interior of the strip-shaped groove, an interdigital electrode is arranged above the insulating substrate, a second humidity-sensitive film is attached to the upper portion of the interdigital electrode, the strip-shaped groove is formed in the substrate, the humidity-sensitive films are attached to the substrate and the interdigital electrode, and the strip-shaped groove can increase the area of the oxidized graphene humidity-sensitive film; the oxygen-containing functional groups on the composite material can easily adsorb water molecules and provide a large number of adsorption sites for the water molecules, so that the humidity sensitivity is improved, the sensitivity and precision of the humidity sensor are improved, and the response speed is accelerated.

Description

Technical Field

[0001] The utility model relates to the field of humidity sensors, in particular to a high-sensitivity humidity sensor based on an inverse opal structure. Background Art

[0002] Wearable humidity sensors have important application prospects in the field of portable medical devices and health monitoring. Since the breathing rate is almost related to the heart rate, the exhaled gas can reflect the body's metabolism and health status. This non-invasive method can monitor hidden symptoms and diagnose diseases. At present, the humidity sensors used for wearables are generally electrical humidity sensors. They are based on the fact that the hygroscopic material reacts with water vapor under different environmental humidity, which causes the electrical parameters such as conductivity or capacitance of the sensor to change. The humidity is identified from the change of electrical parameters. However, this humidity sensor has poor test accuracy, large humidity hysteresis, and a small humidity measurement range. When detecting health status and metabolic status, rapid and sensitive feedback of humidity plays a very important role in the detection structure. Therefore, a fast-response, high-sensitivity humidity sensor is urgently needed. Utility Model Content

[0003] Existing wearable humidity sensors not only have poor test accuracy, low sensitivity, large humidity hysteresis, but also slow response speed. At least one aspect or one purpose of the present application can solve the above problems. Specifically, a high-sensitivity humidity sensor based on an inverse opal structure is designed, and the specific technical solution adopted is:

[0004] A high-sensitivity humidity sensor based on an inverse opal structure comprises an insulating substrate, wherein a plurality of strip grooves are horizontally arranged on the upper surface of the insulating substrate, the plurality of strip grooves are arranged in parallel and spaced apart, each strip groove is in a long strip shape and both ends extend to the edge of the insulating substrate, a first humidity-sensitive film is attached to the strip groove, a forked electrode is arranged above the insulating substrate, and a second humidity-sensitive film is attached above the forked electrode.

[0005] Preferably, the humidity sensitive film is a graphene oxide film.

[0006] Preferably, the interdigitated electrodes are graphene interdigitated electrodes with an inverse opal structure.

[0007] Preferably, the interdigital electrode comprises a substrate, on which two copper wire pins are fixed by conductive silver paste.

[0008] Preferably, the base body is a ceramic substrate.

[0009] Preferably, the insulating substrate is a quartz or ceramic substrate.

[0010] The above-mentioned graphene humidity sensor has an ultra-thin structure and a tiny size, and is suitable for portable electronic devices. In addition, the 3D graphene skeleton structure electrode has orderly arranged holes, which can be precisely controlled as a skeleton structure. Strip grooves are set on the substrate, and a humidity-sensitive film is attached to the substrate and the interdigitated electrodes. The strip grooves can increase the area of ​​the graphene oxide humidity-sensitive film, and the oxygen-containing functional groups thereon can easily adsorb water molecules, providing a large number of adsorption sites for water molecules, thereby improving humidity sensitivity, improving the sensitivity and accuracy of the humidity sensor, and accelerating the response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the utility model.

[0012] In the figure, 1, insulating substrate, 2, strip groove, 3, first humidity-sensitive film, 4, second humidity-sensitive film, 5, interdigitated electrodes, 501, substrate, 502, electrolytic silver paste, 503, copper wire pins. DETAILED DESCRIPTION

[0013] In order to clearly illustrate the technical features of the present invention, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0014] In addition, in the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0015] like Figure 1 As shown, a high-sensitivity humidity sensor based on an inverse opal structure includes an insulating substrate 1, which is a quartz or ceramic substrate. In this embodiment, the insulating substrate 1 can be a quartz substrate or a ceramic substrate. A plurality of strip grooves 2 are horizontally arranged on the upper surface of the insulating substrate 1 along the width direction of the insulating substrate 1. The plurality of strip grooves 2 are arranged in parallel and spaced apart along the length direction of the insulating substrate 1. Each strip groove 2 is long and has both ends extending to the edge of the insulating substrate 1. A first humidity-sensitive film 3 is attached to the strip groove 2. A forked electrode 5 is arranged above the insulating substrate 1. A second humidity-sensitive film 4 is attached above the forked electrode 5. Water molecules can contact the water molecules not only from the upper surface of the second humidity-sensitive film 4, but also from the side of the insulating substrate 1. This increases the adsorption sites of water molecules and improves the sensitivity and response speed of the humidity sensor.

[0016] Furthermore, the first humidity sensitive film 3 and the second humidity sensitive film 4 are graphene oxide films. Graphene oxide is a derivative material of graphene, which has a very large specific surface area and very rich oxygen-containing functional groups. It is easy to adsorb water molecules and provide a large number of adsorption sites for water molecules, thus having humidity-sensitive properties.

[0017] Furthermore, the interdigitated electrode 5 is an inverse opal structure graphene interdigitated electrode 5, and the graphene interdigitated electrode 5 is prepared by dripping a graphene oxide aqueous solution thereon and drying it into a thin film at room temperature. The above-mentioned inverse opal structure graphene interdigitated electrode 5 has a 3D ordered porous structure, which is prepared by the existing inverse opal 3D porous structure preparation method, mainly including the cleaning treatment of the quartz substrate: covering the surface of the quartz substrate with a mask template in the shape of the interdigitated electrode 5, soaking it in a mixture of concentrated sulfuric acid and hydrogen peroxide, and then cleaning off the residual acid.

[0018] Preparation of opal template: The opal ordered template is prepared by vertical deposition method, and polystyrene microspheres or silica microspheres are deposited on the surface of quartz substrate under the combined action of gravity and surface tension.

[0019] Preparation of graphene sol: Dissolve small-diameter single-layer graphene powder in an organic solvent.

[0020] Obtaining a graphene film with an inverse opal structure: the above-mentioned graphene sol is dripped onto the opal template, and penetrated into the gaps of the opal template under the action of gravity, while removing the interdigitated mask, and then removing the microspheres by high-temperature sintering to obtain a 3D ordered porous structure of graphene interdigitated electrodes 5, and copper wires are led out at both ends of the electrode.

[0021] Preparation of humidity sensor: A graphene oxide aqueous solution is drop-coated on the graphene interdigitated electrode 5 and dried at room temperature to form a film.

[0022] Among them, in the process of preparing the opal template by the vertical deposition method, the substrate is placed vertically in a pre-prepared colloidal solution, and the solution on the surface of the substrate will form a meniscus. Due to its strong capillary force, the microspheres are adsorbed to the place where the film thickness is smaller than the microspheres, forming a 3D ordered structure. The number of colloidal crystal layers can be controlled by adjusting the concentration of the colloidal solution; since the size of the microspheres is in the range of 100nm to 800nm, microspheres of different sizes are selected to control the pore size of the prepared skeleton; therefore, the size and number of layers of the graphene film holes can be precisely controlled. In addition, when preparing the graphene sol, the diameter of the filled graphene sheets should match the gap formed by the microspheres. In the process of obtaining the inverse opal structure framework, the method of removing the microspheres is not limited to high-temperature sintering removal, and chemical corrosion, solvent dissolution, etc. can also be used to remove the polymer template to obtain an inverse opal structure graphene film.

[0023] Furthermore, the interdigital electrode 5 includes a substrate 501 , on which two copper wire pins 503 are fixed by conductive silver paste 502 , and the substrate 501 is made of a ceramic substrate.

[0024] The above-mentioned specific implementation manner cannot be used as a limitation on the protection scope of the present utility model. For those skilled in the art, any replacement, improvement or change made to the implementation manner of the present utility model falls within the protection scope of the present utility model.

[0025] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A high-sensitivity humidity sensor based on an inverse opal structure, characterized in that: It includes an insulating base, wherein a plurality of strip grooves are horizontally arranged on the upper surface of the insulating base, wherein the plurality of strip grooves are arranged in parallel and spaced apart, wherein each of the strip grooves is in the shape of a long strip and both ends extend to the edge of the insulating base, wherein a first humidity-sensitive film is attached to the strip groove, wherein interdigitated electrodes are arranged above the insulating base, and a second humidity-sensitive film is attached above the interdigitated electrodes.

2. A high-sensitivity humidity sensor based on an inverse opal structure according to claim 1, characterized in that: The first humidity-sensitive film and the second humidity-sensitive film are graphene oxide films.

3. A high-sensitivity humidity sensor based on an inverse opal structure according to claim 2, characterized in that: The interdigitated electrodes are graphene interdigitated electrodes with an inverse opal structure.

4. A high-sensitivity humidity sensor based on an inverse opal structure according to claim 3, characterized in that: The interdigital electrode comprises a substrate, on which two copper wire pins are fixed by conductive silver paste.

5. A high-sensitivity humidity sensor based on an inverse opal structure according to claim 4, characterized in that: The base body adopts a ceramic substrate.

6. A high-sensitivity humidity sensor based on an inverse opal structure according to claim 1, characterized in that: The insulating substrate is a quartz or ceramic substrate.

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