Well dispersed SnO₂ nanoclusters preparation and modulation of metal-insulator transition induced by ionic liquid^†

Tin dioxide (SnO₂) has attracted broad interest due to its particular gas-sensor property. Nano- or atom-scale SnO₂ material has always been the aim in order to ultimately improve the sensitivity. However, until now, it remains difficult to synthesize SnO₂ nanoclusters by using traditional methods. In the present work, we have achieved the preparation of SnO₂ nanoclusters by using the cluster beam deposition technique. The obtained nanoclusters were well characterized by high resolution transmission electron microscope HR-TEM. Results indicated the formation of the well-dispersed SnO₂ nanoclusters with uniform size distribution (5–7 nm). Furthermore, an obvious metal insulator transition was observed by gating with ionic liquid. Combined with theory calculation, the corresponding mechanism was systematically analyzed from oxygen vacancy induced electron doping.