Solvothermal synthesis of tungsten oxide mesocrystals and their electrochromic performance

Abstract Flower-like W 18 O 49 mesocrystals built from individual single-crystalline nanowires were fabricated using a facile solvothermal method. The as-prepared W 18 O 49 mesocrystals have been systematically characterized by X-ray diffraction, energy dispersive spectroscopy, electron microscopy, selected area electron diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Based on the analyses of cyclic voltammetric curves and UV–vis transmittance spectra, the W 18 O 49 mesocrystals have been found to exhibit stable and reversible electrochromic performance with high color contrast, which can be attributed to their hierarchical architecture, special tunnel structure, and non-stoichiometric characteristics. The novel W 18 O 49 mesocrystals are promising electrochromic candidate for potential application in smart window.