Ratiometric optical fiber carbon dioxide sensor based on CdSe/ZnS QDs and Polym-H7 doped in EC matrix

This study focuses a new ratiometric optical fiber carbon dioxide (CO₂) sensor based on CdSe/ZnS QDs and pH sensitive dye Polym-H7, those were immobilized within the Ethyl cellulose (EC). These CO₂ sensing materials were coated on the surface of the optical fiber end and a 375 nm LED light was employed as an excitation source, it is shown that the emission wavelength of fluorescence dyes have no spectral overlap, so the fluorescence intensity ratio of two dyes can be used to design a ratiometric optical fiber CO₂ sensor. The experimental result reveals the sensitivity of ratiometric optical fiber carbon dioxide sensor as R₀/R=1.84 and exhibits a uniquely linear response for CO₂ concentrations in the range of 0-100%. The suggested new ratiometric sensing approach suppresses the effects of imitation fluctuations in the intensity of excitation source.