Co-doping effect of Zn and Sb in SnO2: Valence stabilization of Sb and expanded solubility limit

In this study, the co-doping effect of ZnO and Sb2O5 on the solubility limit in SnO2 was investigated. When ZnO was added to SnO2, its solubility limit was around 3 at%, while that of Sb2O5 could not be evaluated due to the severe evaporation of Sb2O5 during sintering. For the co-doping of ZnO and Sb2O5, the ZnSb2O6 phase was used for the source of Zn and Sb dopants to prevent the evaporation of Sb2O5. When ZnO and Sb2O5 were co-doped by ZnSb2O6, the solubility limit expanded to 60  at%. XPS analysis of the Sb revealed that Sb5+ is stable when Zn is co-doped. The extended solubility limit is explained by electrostatic and strain energy minimization in the lattice.