Dopant-induced cationic bivalency in hierarchical antimony-doped tin oxide nano-particles for room-temperature SOsensing

The modification of simultaneously existing multiple oxidation states in host lattice cationsviathe introduction of dopants has been reported for NiO- and CoO-based gas-sensing materials. However, SnO, a widely used material for chemiresistive gas sensing has never been reported with simultaneous presence of Snand Snstates, in both the absence and presence of dopants. In this work, we demonstrated how antimony doping in a 3+ state triggers the generation of cationic bivalency in tin oxide-based gas sensors, and it is the quantitative presence of unstable Snspecies that determines the fate of SO-sensing responses by antimony-doped tin oxide gas sensors. While the Sncontent in SnSbOis 1.2 times less than that of SnSbO, the SOsensing response in the former is 1.2 times more than that in the latter. Greater antimony content in SnSbOalso leads to the generation of additional trap states that result in sequential return of electrons back into the valence band. The reversibility of Sn↔ Snduring SOadsorption and desorption brings out a new dimension of SnO-based chemiresistors besides those already existing.