Electrochemical properties of Sol-gel WO3 films Co-doped with Ti and Zn

WO3 nanoparticles doped with Ti (W1-xTixO3) and co-doped with Ti and Zn (W1-xTix-YZnyO3) have been prepared on FTO/glass substrate, using wet chemical method (dipping in a sol-gel). The Ti molar concentration into W1-xTixO3 ranges 0-30 % in steps of 5%. Best electrochromic properties were observed for composition that has Ti nominal concentration of 5% (W0.95Ti0.05O3). This was evidenced from cyclic voltammetry (CV), chronoamperometry (CA), and transparency during CA measurements. The composition that gives best electrochromic properties (W0.95Ti0.05O3) was chosen to prepare WO3 nanocrystallite films co-doped with Zn for the first time (W0.95Ti0.05-yZn yO3). The Zn molar concentration in these films varied 1-5%. From CV and CA measurements, Co- doped WO3 films showed better electrochromic performance than Ti single doped films. From co-doped films, the best electrochromic properties were observed for films that contains 3% of Zn (W0.95Ti0.02Zn0.03O3). The transparency spectrum of W0.95Ti0.02Zn0.03O3 electrode shows a high improvement in coloration efficiency compared to the coloration efficiency of W0.95Ti0.05O3 electrode. The stability of the prepared materials is also tested in H2SO4 electrolyte, though cycling electrodes for at least 6000 cycles.