Large directional conductivity change in chemically stable layered thin films of vanadium oxide and a 1D metal complex

Abstract

Electroactive hybrid and layered oxides and related materials where the inorganic phase is the host, offering the conductivity characteristics of semiconductors, have been used in thin film transistors and related electronic devices where the host–guest interaction offered conductivity with improved processability. We describe the synthesis and characterization of a nanocomposite that shows large conductivity anisotropy when deposited as a thin film. We prepared the material by inserting quasi 1-dimensional potassium tetracyanoplatinate metal complexes with insulating electrical properties in between stacked nanosheets of vanadium oxide xerogels. Detailed structural and compositional analysis using transmission electron microscopy and X-ray photoelectron spectroscopy confirms that the hybrid material forms from a topotactic reaction and the framework of the layered host oxide structure is maintained. The hybrid film demonstrates a ∼1000-fold conductivity change between transport parallel and perpendicular to the film at room temperature. Temperature dependent transport measurements confirm Ohmic conduction perpendicular to the stack and small polaron hopping conduction parallel to the layering direction of the film. The conductivity anisotropy and simple synthesis demonstrate that nanostructured layered hybrids can provide alternative materials for thin film complementary logic and resistive memory.