Vacancy-defect assisted electrochromic applications in V2O5 nanomaterials

Vacancy defects can result in visible imperfections in the material’s lattice structure; however, they also enhance its effectiveness in various applications. In the present study, we have experimentally investigated how vacancy defects influence the electrochromic properties. This study presents a comparative analysis of the electrochromic (EC) properties of V₂O₅ thin films synthesized using ammonium metavanadate (NH4VO2) and commercially available V2O5 via a hydrothermal approach. Structural and morphological analyses were performed to confirm the formation of a microporous network and a nanosheet of V2O5 nanomaterials. Furthermore, X-ray photoelectron spectroscopy (XPS) was employed to investigate oxygen vacancies in V2O5 films. The cyclic voltammetry (CV) and in-situ optical variation results highlighted the positive impact of oxygen vacancies on the EC performance. The maximum coloration efficiency of multicolored V2O5-N thin films were 96.23 cm2 C−1 at a 633 nm wavelength, with 500 color/bleach cycles in 0.5 M LiClO4 + PC electrolytes. The microporous network and nanosheet morphology of V2O5 thin films exhibited distinct optical hues with excellent long-term EC cycling stability. The high coloration efficiency (CE) and EC stability of V2O5 thin films prepared using NH4VO2 demonstrate the significant impact of oxygen defects.