Surface acoustic wave (SAW) formaldehyde gas sensor using water to absorb formaldehyde

A surface acoustic wave, formaldehyde gas technology, applied in the direction of using sonic/ultrasonic/infrasonic waves to analyze fluids, etc., can solve the problem that the performance of the surface acoustic wave formaldehyde sensor cannot meet the actual needs, and achieve the effect of small molecular mass and high detection sensitivity

Active Publication Date: 2014-01-15
CHINA ELECTRONIC TECH GRP CORP NO 38 RES INST
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  • Abstract
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Problems solved by technology

(See Specifications for Control of Indoor Environmental Pollution in Civil Construction Engineering (2006 Edition)-GB50325-2001; National Occupational Health Standard of the People's Republic of China GBZ2.1-2007 Occupational Exposure Limits of Harmful Factors in the Workplace) Therefore, the performance of the current surface acoustic wave formaldehyde sensor unable to meet actual needs

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  • Surface acoustic wave (SAW) formaldehyde gas sensor using water to absorb formaldehyde

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Experimental program
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Effect test

Embodiment 1

[0030] The piezoelectric substrate 1 chooses ST-quartz, the electrode 2 chooses aluminum, the conductive particle material of the conductive sensitive film 3 chooses carbon nanotubes, and the material for absorbing water vapor is the same as that of the insulating sensitive film 4, and chooses dodecyl alcohol.

[0031] The preparation method of surface acoustic wave formaldehyde gas sensor provided by the present invention is as follows:

[0032]A layer of aluminum film with a thickness of about 0.55 μm is prepared on the front surface of the piezoelectric substrate 1 by vacuum thermal evaporation process. Then use the spin coating process to deposit a layer of photoresist on the surface of the aluminum film. After pre-baking at 100°C for 1 minute, cover the surface with a photoresist, expose for 10 seconds, remove the photoresist, and develop at 25°C N(CH3)4OH Soaked in the solution for 5 seconds, the exposed photoresist dissolves, exposing the aluminum film, and the covered ...

Embodiment 2

[0034] Lithium niobate is selected for the piezoelectric substrate 1, gold / titanium is selected for the electrode 2, and titanium is used as an intermediate layer between the substrate and the gold film to improve the adhesion of the gold film, and carbon black is selected for the conductive particle material of the conductive sensitive film 3 , The material for absorbing water vapor is the same as the insulating sensitive film 4, and polyvinyl acetate is selected.

[0035] Preparation of interdigitated electrodes by stripping process: Spin-coat a layer of photoresist, and after pre-baking at 100°C for 1 minute, cover a photoresist plate on the surface, expose for 10 seconds, remove the photoresist plate, and heat at 25°C in N(CH3)4OH After soaking in the developing solution for 5 seconds, the exposed photoresist dissolves, exposing the piezoelectric substrate (1), and the covered photoresist remains. After rinsing with deionized water, bake at 180°C for 20 minutes; use the ma...

Embodiment 3

[0037] The piezoelectric substrate 1 is lithium niobate, the electrode 2 is aluminum, the conductive particle material of the conductive sensitive film 3 is gold nanoparticles, and the material for absorbing water vapor is the same as that of the insulating sensitive film 4, and polysiloxane is selected.

[0038] A layer of aluminum film with a thickness of about 0.55 μm is prepared on the front surface of the piezoelectric substrate 1 by vacuum thermal evaporation process. A layer of photoresist is deposited on the surface of the aluminum film by spin-coating process. After pre-baking at 100° C. for 1 minute, a photoresist plate is covered on the surface, and the photoresist plate is removed after exposure for 10 seconds. 3 ) 4 Soak in OH developer for 5 seconds, the exposed photoresist dissolves, exposing the aluminum film, and the covered photoresist remains. After rinsing and baking at 180° C. for 20 minutes, the aluminum film in the area not covered by the photoresist is...

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Abstract

The invention discloses a surface acoustic wave (SAW) formaldehyde gas sensor structure using water to absorb formaldehyde. The surface acoustic wave (SAW) formaldehyde gas sensor structure comprises a piezoelectric substrate, electrodes, a conductive sensitive film, an insulated sensitive film and an electric lead, wherein the conductive sensitive film and the insulated sensitive film absorb steam, and the steam absorbs formaldehyde gas. After the formaldehyde gas is absorbed, the conductivity of the conductive sensitive film is changed, but the insulated sensitive film is not changed, so that corresponding output frequency is changed, and a difference between the conductivity and the insulated sensitive film is response of the sensor to the formaldehyde gas. The surface acoustic wave (SAW) formaldehyde gas sensor has the advantages as follows: aiming at the characteristics of formaldehyde, such as low boiling point, small molecular mass and high water-solubility, the surface acoustic wave (SAW) formaldehyde gas sensor is specially developed, the detection sensitivity is high, and manual sampling is needless.

Description

technical field [0001] The invention relates to the technical field of gas sensors, in particular to a surface acoustic wave formaldehyde gas sensor. Background technique [0002] Formaldehyde is easily soluble in water. This feature is widely used in the field of formaldehyde gas detection, including the national standard "Methods for the determination of formaldehyde in the air in public places" GB / T18204.26-2000 and some on-site rapid detection equipment. Kawamura et al. used AHMT (4-amino-3-azino-5-sulfanyl-1,2,4-triazolene) and potassium hydroxide solution as the absorption liquid, and dropped 100 μL of the absorption liquid on a circular On the filter. The filter is exposed to formaldehyde gas, the water in the solution absorbs the formaldehyde gas, and then the AHMT reacts with the formaldehyde, resulting in a color change. The color intensity change is measured by the intensity of the photodiode emission tube (see Sensors and Actuators B, Vol. 105, 495-501, 2005). ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/036
Inventor 胡佳李臻余琳单志林张婧
Owner CHINA ELECTRONIC TECH GRP CORP NO 38 RES INST
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