Chemiresistors Based on SnO2, TiO2 and SnO2/TiO2 Films for Possible Sensing of Na+ and Ca2+ ions

Semiconductor metal oxide films have been used in sensing-based applications, and they are typically prepared by vacuum deposition techniques. In this study, we used solution-processed semiconductor metal oxides to investigate their sensitivity for cations in aqueous solution. Specifically, solution-processed tin(IV) oxide (SnO
2
), titanium dioxide (TiO
2
) and a composite of SnO
2
/TiO
2
were deposited on fluorine-doped tin oxide (FTO) glass and these were tested for their chemiresistive properties when exposed to cationic species in solution. Techniques such as grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and the surface profiler were utilized to characterize the metal oxide films.