Accurate, continuous and precise monitoring of dissolved and gaseous carbondioxide(CO2) is vital in industrial, chemical, medical and atmosphericanalysis. In this study, SnO2 and Ni-doped SnO2 powderswere added as additives to increase gas sensitivity to8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) dye, which is a commercialfluorescent indicator with high sensitivity to CO2 gas.Characterizations of synthesized metal oxide semiconductors (MOSs) wereperformed using photoluminescence spectroscopy (PL), X-ray photoelectronspectroscopy (XPS), X-ray diffraction spectroscopy (XRD) and scanning electronmicroscope (SEM). HPTS-based thin films were prepared by immobilizing dye andMOSs additives to ethyl cellulose (EC) matrix. Steady-state measurements, decaytime kinetics and kinetic measurements of the sensor agents were measured inthe concentration range of 0-100% [CO2]. The addition of SnO2-basedsemiconductors to the HPTS-based composites has resulted in many improvements insensor dynamics such as higher sensitivity, relative signal variation andlarger linear response range according to the additive-free form. The CO2sensitivities of HPTS dye were measured as 4.7, 12.6 and 57.5 fold for theundoped and SnO2 and Ni-doped SnO2 doped forms,respectively. The response and recovery times of the HPTS-based sensing slideagainst CO2 with Ni-doped SnO2 powders were measured as 38and 156 s. These results make the HPTS fluorophore with SnO2 and Ni-doped SnO2additives into more advanced sensor agents for sensitivity to CO2gas and show it as a promising candidate for CO2 probes.</p
