The electrochromic properties and mechanism of [formula omitted] and [formula omitted

Abstract

The concentration of hydrogen and lithium ions in colored and bleached WO 3 films was measured by secondary ion mass spectroscopy (SIMS) depth profile analysis and inductively coupled plasma mass spectroscopy. X-ray analysis revealed that as-prepared WO 3 films changed to a mixture of WO 3 and tungsten bronze ( H x WO 3 or Li x WO 3 ) during the electrical coloration process. Poly-AMPS, 10% H 2SO 4 aqueous solution, and 1M LiClO 4-propylene carbonate (PC) were used as the electrolytes. The crystal structure of colored films changed back to the initial state when the films were bleached, even though a large quantity of hydrogen or lithium atoms still remained inside bleached films. We proposed that a fraction of hydrogen or lithium cations will bind on optically inactive sites, possibly the grain boundaries of the WO 3 polycrystalline film in the bleaching process, and will not contribute to the coloration.