engleski

Novel counter electrode based on mixed vanadium cerium oxides : preparation and characterization.

Mixed vanadium cerium (V/Ce) oxides thin films at 71, 55, 38 and 32 atomic % of V were obtained via inorganic sol-gel process. Our films were prepared for counter electrode in electrochromic devices for smart windows. V2O5 is reversible, fast, but when the voltage was swept in the wider range, disordered materials was obtained with continuous decrease of intercalation/deintercalation properties. The addition of Ce precursors improved the stability of vanadium oxide with the ion-charge capacity up to 30 mC cm-2. All films were investigated by cyclic voltametry (CV), IR spectroscopy, UV-VIS technique and atomic force microscopy (AFM). The best intercalation properties of Li+ ions and cycling durability were obtained for films prepared at 55, and 38 at % of V. The morphology of these nanostructured and porous films was studied by grazing-incidence small-angle X-ray scattering (GISAXS). We found that the effects of the different times of annealing, cycling and sonification are diverse for surface and bulk properties of films with 55 at % of V. These are shown to be the critical parameters and treatments in sol-gel preparation of the nanostructured vanadium oxide films to be used as electrodes in new optoelectronic devices for smart windows.

(V/Ce) oxides; GISAXS; UV-VIS; IR spectroscopy; CV; AFM

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