Effect of substrate pre-treatment on microstructure and enhanced electrochromic properties of WO3 nanorod arrays

Abstract

WO₃ nanorod arrays (WNRAs) were successfully synthesized on an FTO substrate pre-coated with a layer of TiO₂ seeds. The morphology and micro-structure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). The effect of substrate pre-treatment on electrochromic (EC) properties of as-prepared WNRAs was investigated in detail. Compared with those synthesized on WO₃ seed layer, the WNRAs grown on TiO₂ seed layer showed a large optical modulation (77.5%, at 660 nm) and high coloration efficiency (142.7 cm² C⁻¹) under the optimal preparation conditions. In addition, the influence of annealing temperature of the TiO₂ seed layer on the EC performance was also discussed. More importantly, the WNRAs grown on the TiO₂ seed layer presented good stability and strong adhesion to the FTO substrate during the test process.