WO3 electrochromic thin films doped with Ti and/or co-doped with Zn
atoms have been prepared, onto FTO/Glass substrates, by sol-gel technique.
WO3nominally doped with 0.05% of Ti (W0.95Ti0.05O3) was co doped with
Zn nominal molar concentration according to W0.95Ti0.05-xZnxO3. Different
optical and electrochromic parameters have been studied; Cyclic
voltammetry (CV), Chronoamperometry (CA), and transparency during CA
experiment was used to study the electrochromic and optical parameters.
Best electrochromic properties was observed for co-doped film with
nominal composition of W0.95Ti0.04Zn0.01O3, and this film showed the
highest contrast ration (Tb/Tc ≈ 1.9). Also, this film has highest coloration
efficiency (22.2 cm2/C), which is 1.55 times higher than WO3 doped with Ti
alone (W0.95Ti0.05O3). FTO thickness increases by 79 nm for single dipping
in the sole-gel and the film increased by other 400 nm when dipped for
another time. Moreover, Energy band gap was found to be 3.92 eV, 3.83 eV
and 3.79 eV for single layer, double layer and triple layer respectively.