Enhanced Electrochromic Tungsten Oxide by Bio-Inspired Brochosomes

Electrochromic materials have promising applications in diverse fields. Motived by natural color-changing living species through manipulating their microstructures, we explored the electrochromic performance of the WO3 brochosomes with a microscale hollow structure indented by sub-microscale pits modeled after the leafhopper-secreted natural ones. The WO3 brochosomes demonstrated better electrochromic performance than and comparable cyclability to the planar WO3, induced by their novel ordered structures. The unique structure allows fast ion transportation within WO3 brochosomes, leading into high reflectance modulation (about 30.85% at 633 nm) and short response time (0.25 s/ 0.18 s for coloration/bleach, respectively). The relationship between the electrochromic performance and the brochosomes structure was built based on systematical electrochemical and optical studies. The artificial color-changing brochosomes might be able to mimic natural color-changing living species with promising applications in energy-saving and camouflage fields.