V0.50Ti0.50Ox thin films as counterelectrodes for electrochromic devices

Thin films of V_0.50Ti_0.50O_x have been deposited by RF sputtering from metallic targets. Their use as potential counterelectrodes in electrochromic devices has been investigated. It is found that although they are slightly yellow looking in transmission, the films can reversibly store relatively large amounts of charge, whilst showing a reasonably low electrochromic colouration efficiency. The electrochemistry of V_0.50Ti_0.50O_x is found to be simple, in fact rather similar to that of WO₃, making it an almost ideal material to use in such a variable transmission device.