2D Metal oxide nanosheets and their applications in advanced electronic materials

Metal oxide nanosheets are the oxide equivalents of graphene. They have thicknesses of 0.5-2.5 nm and lateral sizes up to tens of micrometers. Oxide nanosheets can be made by delamination of layered metal oxides in water using... [ view full abstract ]

Metal oxide nanosheets are the oxide equivalents of graphene. They have thicknesses of 0.5-2.5 nm and lateral sizes up to tens of micrometers. Oxide nanosheets can be made by delamination of layered metal oxides in water using a combination of acid-base & ion exchange reactions, or by direct bottom-up growth from chemical solutions. A wide range of compositions and 2D structures can thus be made. Two applications of oxide nanosheets will be demonstrated in this presentation: (1) Since nanosheets are 2D single crystallites with only one type of surface termination, they are versatile seed layers for growth of oriented and epitaxial functional metal oxides. Oriented perovskite-type thin films of SrRuO₃, (La,Sr)MnO₃, Pb(Zr,Ti)O₃ and BiFeO₃ have been grown on Ca₂Nb₃O₁₀ and Ti_0.87O₂ nanosheets using pulsed laser deposition. Depending on the nature of the seed layer, either [001] or [110] oriented perovskite films are formed, and the ferromagnetic and piezoelectric properties are controlled by the domain size and preferential orientation of the as-grown films. (2) MnO₂ nanosheets can be used as active electrode elements for micro-supercapacitors. The fabrication of nanosheet-based microsupercapacitors by ink-jet printing on flexible plastic substrates is demonstrated. As will be shown, their device characteristics are similar to state of the art supercapacitors.