WO3 nanorolls self-assembled as thin films by hydrothermal synthesis

Abstract

We report a novel type of WO₃ nanostructure, i.e. nanorolls obtained as a self-assembled thin film on a transparent conductive substrate. The mild conditions of preparation, avoiding the use of HCl, result in an eco-friendly hydrothermal method with reduced crystallization time. FESEM and HR-TEM show that WO₃ nanocrystals are made of rolled nanoflakes with a telescope-like appearance at their tip. For their nano-porosity, electrochemical accessibility, good adhesion to substrates and the envisaged presence of nanocavities between the WO₃ layers, these materials hold tremendous promise in nano-electronics, electrochromic devices, water photo-splitting cells, Li-ion batteries and nano-templated filters for UV radiation.