On the preparation of Tri-vanadium hepta-oxide thin films for electrochromic applications

Nanostructured Tri-vanadium hepta-oxide (V3O7) thin films for electrochromic devices having high optical modulation, enhanced optical density, multi-coloration, fast switching time, and better reversibility, were prepared by nebulizer spray pyrolysis technique with 400 degrees C substrate temperature. A monoclinic structured, V3O7 films having nano rod-like morphology have been observed from structural and surface morphological analyzes, respectively. Surface chemical analyzes revealed the mixed vanadium oxidation states that favored the formation of relatively stable V3O7 thin films. Electrochromic performance of the films was examined by electrochemical cyclic voltammetry (CV) studies with multiple CV scan rate. The multiple peaks present in the anodic and cathodic curves prove the multi-coloration behavior of the films with appreciable optical modulation in the visible range of light.