Electrochromic Properties of WO3 doped with Ti and Zn atoms

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غنمه, سلام عدنان محمود
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An-Najah National University
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. WO3 nominally doped with 0.05% of Ti (W0.95Ti0.05O3) was co doped with Zn nominal molar concentration according to W0.95Ti0.05-xZnxO3, where x ranges from 0 - 5 %. For these films, different optical and electrochromic parameters have been studied. Cyclic voltammetry (CV), Chronoamperometry (CA), and transparency during CA experiment was used to study the electrochromic parameters. Best electrochromic properties was observed for co-doped film with nominal composition of W0.95Ti0.04Zn0.01O3. Compared to all studied films, this film (W0.95Ti0.04Zn0.01 O3) showed the highest contrast ration (Tb/Tc ≈ 1.9). Also, this film has highest coloration efficiency (22.2 cm2/C), which is 1.48 times higher than WO3 doped with Ti alone (W0.95Ti0.05O3). Moreover, co-doped film has a good switching time and excellent reversibility (Qa/Qc ≈ 0.95 ), which are almost same as single doped film. FTO thickness increased by 79 nm for single dipping in the sole-gel and the film thickness increased by other 479 nm when dipped for another time. Moreover, Energy band gap was found to be 3.91 eV, 3.87 eV and 3.83 eV for single layer, double layer and triple layer respectively.