Carbon dioxide gas sensor with ionic gel

This paper reports on a low-power-consumption carbon dioxide (CO
₂
) gas sensor based on an ionic gel. Ionic gel is a mixture of ionic liquid and polymer. We employed 1-ethyl-3-methyl-imidazolium tetrafuloroborate ([EMIM][BF
₄
]) as ionic liquid and polyvinylidene fluoridecohexafluoro propylene (PVDF-HFP) as polymer. The [EMIM][BF
₄
] selectively absorbs CO
₂
gas. Our proposal sensor consisted of an ionic gel and two Pt electrodes patterned under the ionic gel. The CO
₂
gas concentration can be detected by measuring the electrochemical impedance between the two electrodes. The sensor was able to measure the difference of 500 ppm CO
₂
gas concentration by using power as small as 0.65 μW.