Prominent electrochromism through vacancyorder melting in a complex oxide

摘要

Electrochromes are materials that have the ability to reversibly change from one colour state toanother with the application of an electric field. Electrochromic colouration efficiency is typicallylarge in organic materials that are not very stable chemically. Here we show that inorganicBi0.9Ca0.1Feo3 0.05 thin films exhibit a prominent electrochromic effect arising from anintrinsic mechanism due to the melting of oxygen-vacancy ordering and the associatedredistribution of carriers. We use a combination of optical characterization techniques inconjunction with high-resolution transmission electron microscopy and first-principles theory.The absorption change and colouration efficiency at the band edge (blue-cyan region) are4.8×106m~(-1) and 190cm2C~(-1), respectively, which are the highest reported values for inorganicelectrochromes, even exceeding values of some organic materials.