Capacitive gas sensor and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-12590918-B2
Application number	US-202318192899-A
Country	US
Kind code	B2
Filing date	Mar 30, 2023
Priority date	Nov 25, 2020
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

Provided is a capacitive gas sensor. The capacitive gas sensor comprises a sensitive material for adsorbing and desorbing a target gas, an upper electrode surrounding the sensitive material, a lower electrode facing the upper electrode, and a porous structure disposed between the upper electrode and the lower electrode, wherein the capacitance of the sensitive material changes as the sensitive material adsorbs and desorbs the target gas.

First claim

The invention claimed is:

1 . A capacitive gas sensor comprising:
a sensitive material for adsorbing or desorbing a target gas; an upper electrode surrounding the sensitive material; a lower electrode facing the upper electrode; and a porous structure disposed between the upper electrode and the lower electrode, wherein a capacitance of the capacitive gas sensor changes as the sensitive material adsorbs or desorbs the target gas, wherein the upper electrode has a ring shape with a hollow formed at a central portion thereof, wherein the lower electrode has a circle plate shape, wherein the sensitive material is disposed in the hollow formed at the central portion of the upper electrode, and wherein the porous structure includes anodic aluminum oxide (AAO).

2 . The capacitive gas sensor of claim 1 , wherein a frequency of a voltage applied to the upper electrode and the lower electrode is differently controlled according to a type of the target gas.

3 . The capacitive gas sensor of claim 2 , wherein
the target gas includes a methanol gas, a toluene gas, or an acetone gas, and the target gas is selectively sensed according to the frequency of the voltage applied to the upper electrode and the lower electrode.

4 . The capacitive gas sensor of claim 3 , wherein, when the frequency of the voltage applied to the upper electrode and the lower electrode is 10 kHz or greater and 1 MHz or less, the methanol gas is sensed.

5 . The capacitive gas sensor of claim 3 , wherein, when the frequency of the voltage applied to the upper electrode and the lower electrode is greater than 800 Hz and less than 3,000 Hz, the toluene gas is sensed.

6 . The capacitive gas sensor of claim 3 , wherein, when the frequency of the voltage applied to the upper electrode and the lower electrode is greater than 300 Hz and less than 800 Hz, the acetone gas is sensed.

7 . The capacitive gas sensor of claim 1 , wherein the sensitive material includes any one of graphene, carbon nanotube (CNT), amorphous carbon, active carbon, and biochar.

8 . The capacitive gas sensor of claim 1 , wherein
the sensitive material includes a functional group including a carboxyl group (—COOH) and a hydroxyl group (—OH), and the target gas is adsorbed or desorbed by the functional group.

Assignees

• Iucf Hyu Erica Campus

Inventors

• Choa Yong Ho
• Park Ji Young
• Lim Min Seob
• Cho Hong Baek
• Lee Han Seung

Classifications

• G01N33/0036

  specially adapted to detect a particular component (physical analysis of gaseous biological material G01N33/497) · CPC title

• G01N33/00

  Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00 · CPC title

• G01N27/221 Primary

  by investigating the dielectric properties (using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26) · CPC title

• G01N27/227 Primary

  Sensors changing capacitance upon adsorption or absorption of fluid components, e.g. electrolyte-insulator-semiconductor sensors, MOS capacitors (G01N27/225 takes precedence) · CPC title

• G01N2027/222

  for analysing gases · CPC title