Hierarchical structure Ti-doped WO3 film with improved electrochromism in visible-infrared region

Hierarchical structure Ti-doped WO3 thin films are prepared by a template-free hydrothermal method. The influence of Ti doping on the electrochromic properties of WO3 thin films is investigated in the visible-infrared region. Ti doping can lead to significant surface morphology change and lower the crystallization, which plays an important role in the electrochromic properties of WO3 films. The large transmittance modulation (49.1% at 750 nm, 64.6% at 2000 nm and 59.3% at 10 mu m), fast switching speed (1.7 s and 1.6 s) and high coloration efficiency (68 cm(2) C-1 at 750 nm) are achieved for the low Ti-doped WO3 film. The enhancement in the electrochromic performance of the low Ti-doped WO3 films is attributed to their low crystallization, a star-like structure which has low charge transfer and ion diffusion resistance, leading to superior electrical conductivity and reaction kinetics.