Influence of molybdenum trioxide thin film thickness on its electrochemical properties

ABSTRACT

Molybdenium trioxide (MoO₃) thin films of one to ten coatings were obtained. The X-ray diffractograms of the xerogels revealed the formation of α-orthorhombic phase of MoO₃ with index plane of 020 and crystallite size of 45 nm. The electrochemical reversibility upon Li⁺ intercalation/deintercalation was confirmed by cyclic voltammetry, and the best anodic (Qa = 25 mC cm⁻²) and cathodic charge (Qc = 25.5 mC cm⁻²) ratio of 0.98 was obtained for the nine-layered film. This film changed 43% of its transmittance between blue and transparent states. SEM evidenced a grain structured film surface and 376 nm thickness of nine-layered MoO₃ film, and the Atomic Force Microscopy (AFM) showed a dense morphology with roughness of 54 nm.

KEYWORDS:

• Electrochromism
• molybdenum trioxide
• spin coating
• sol-gel
• thin films

Funding

This work was financially supported by CNPq (grant 201820/2014-5), and FAPERGS.