Synthesis and characterization of MoO ₃ –WO ₃ composite thin films by liquid phase deposition technique: Investigation of its photochromic properties

Abstract

In order to achieve high colouration efficiency, MoO ₃ –WO ₃ composite thin films have been successfully deposited on sodium silicate glass and silicon wafer (111) at 30 $^{\boldsymbol{\circ}}$C by a very simple novel wet process known as liquid phase deposition. The deposited films were annealed at different temperatures and characterized by carrying out SEM, EDAX, UV-vis and XRD analyses. The EDAX and SEM analyses support the structure and existence of peaks corresponding to Mo, W and O. X-ray diffraction studies showed that MoO ₃ –WO ₃ is amorphous at lower temperature and turns crystalline at higher annealing temperature and suggested the mixture of two crystalline phases such as orthorhombic–monoclinic. Photochromic properties of the MoO ₃ –WO ₃ composite films were studied in the spectral region 400–1200 nm by illuminating them in polychromatic light. The photochromic behaviour is observed to be more effective in composites films in visible region.