Abstract
Abstract
Fiber-optic CO2 sensors are free of electromagnetic interference and highly resistant to corrosion but often require expensive measurement systems or sophisticated preparation procedures. To address this challenge, we developed a CO2 sensor comprising a hetero-core fiber-optic surface plasmon resonance sensor coated with an ionic liquid (IL) gel as a cost-effective CO2 sensing system. Among the various sensors tested, the sensor using ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) as the IL, prepared at a pull-up speed of 4.5 mm s−1, showed the best CO2 sensing performance. A hybrid membrane of [EMIM][BF4] and a CO2-absorbing polymer (monoethanolamine) demonstrated higher sensitivity for CO2 concentrations ranging from 0 to 100%. The highlight of the proposed system is its low-cost configuration comprising an 850 nm-wavelength LED and a photodiode as the light source and signal detection device, respectively. Along with facile preparation and low-cost system configuration, the proposed system exhibited significant potential for CO2 sensing in various fields.