Solution-processable three-dimensional honeycomb-like poly(3,4-ethylenedioxythiophene) nanostructure networks with very fast response speed for patterned electrochromic devices

The solution-processable three-dimensional honeycomb-like poly(3,4-ethylenedioxythiophene) (H-PEDOT) nanostructure networks were fabricated by hard template method for the first time. The morphology, structure and electrochromic performance of the H-PEDOT nanostructures were characterized. Compared with pure PEDOT film, the H-PEDOT nanostructured film shows improved electrochromic properties, including larger optical contrast, shorter response time (0.8 s for bleaching and 0.9 s for coloring), higher coloration efficiency. The improvement of electrochromic performance is due to the highly porous honeycomb-like morphology, which could shorten ion diffusion length and provide more active sites for charge-transfer reactions. In addition, the H-PEDOT nanostructured film was assembled into patterned all-solid-state electrochromic devices. These patterned electrochromic devices show obvious color variation and fast switching speed. The patterned electrochromic displays exhibit promising applications in energy-efficient displays, e-books and e-cards.