Electron microscopy and diffraction analysis of nano-structured prussian blue thin films

Abstract

Prussian blue (PB) thin films have been deposited galvanostatically on transparent conducting coated glass plates with a current density of 20 <img src='/image/spc_char/micro.gif' border=0>A/cm² using equivolume mixture of 10 mM FeCl₃ and 10 mM K₃Fe(CN)₆ in 0.01 N HCl. During deposition the process conditions have been suitably varied to obtain electron beam transparent thin films. A transmission electron microscope has been extensively used to understand the microstructural features at nano-scale, evolved during deposition and the respective selected area electron diffraction patterns have also been studied to reveal amorphous and crystalline behaviour of nano-grains in the microstructure. A detailed characterization of these films illustrated that the films in general constituted of amorphous nano-grains (20-100 nm) with some regions consisting of crystalline phase in the microstructure. The fine details associated with structure and microstructure of PB thin films have been discussed and correlated with their electro-chromic properties