Amorphous Tungsten Oxide Nanodots for Chromatic Applications

Amorphous tungsten oxide (WO 3 ) is widely exploited in the fields of photochromism and electrochromism. Despite its widespread use, the tractable synthesis of amorphous WO 3 nanodots is still on the drawing board, even though the WO 3 nanodots possess superior chromatic performance owing to their large surface‐to‐volume ratio. Therefore, a new efficient strategy to synthesize amorphous WO 3 nanodots, which exhibit both excellent electrochromic and photochromic properties, is reported. For the first time, the ligand effects of the amorphous WO 3 nanodots on chromatic applications are elucidated. The presence of the ligand on amorphous WO 3 nanodots inhibits the electrochromic color switching, while promoting photochromic performance. As a proof of concept, zinc‐WO 3 electrochromic devices, WO 3 ‐polyvinyl alcohol (PVA) transparent hydrogels, and PVA/WO 3 textiles are prepared for diverse rapid‐switching chromatic applications. These results present a new strategy for the synthesis of widely used amorphous WO 3 nanodots and open new opportunities for the development of WO 3 ‐based chromatic applications.