Enhanced electrochromic performance of composite films by combination of polyoxometalate with poly(3,4-ethylenedioxythiophene)

Abstract

A composite film containing poly(3,4-ethylenedioxythiophene) (PEDOT), polyoxometalate (POM) clusters K₆P₂W₁₈O₆₂·14H₂O (P₂W₁₈) and polyallylamine hydrochloride (PAH) was fabricated by a smart combination of layer-by-layer (LbL) with electro-polymerization methods. The composite film displays enhanced electrochromic performance by incorporation of P₂W₁₈ into the PEDOT film. The electrochromic property of the film is significantly improved, resulting in an optical contrast of 54.7% at 600 nm and an absorbance that does not change after 1500 cycles. Additionally, the film provides broader absorption throughout the visible region. These results demonstrate the essential role of POMs in improving functionality on PEDOT for applications in electrochromic devices.