Amorphous Tungsten Oxide Nanodots for Chromatic Applications

Amorphous tungsten oxide (WO3) is widely exploited in the fields of photochromism and electrochromism. Despite its widespread use, the tractable synthesis of amorphous WO3 nanodots is still on the drawing board, even though the WO3 nanodots possess superior chromatic performance owing to their large surface-to-volume ratio. Therefore, a new efficient strategy to synthesize amorphous WO3 nanodots, which exhibit both excellent electrochromic and photochromic properties, is reported. For the first time, the ligand effects of the amorphous WO3 nanodots on chromatic applications are elucidated. The presence of the ligand on amorphous WO3 nanodots inhibits the electrochromic color switching, while promoting photochromic performance. As a proof of concept, zinc-WO3 electrochromic devices, WO3-polyvinyl alcohol (PVA) transparent hydrogels, and PVA/WO3 textiles are prepared for diverse rapid-switching chromatic applications. These results present a new strategy for the synthesis of widely used amorphous WO3 nanodots and open new opportunities for the development of WO3-based chromatic applications.