High performance visible and near-infrared region electrochromic smart windows based on the different structures of polyoxometalates

High performance polyoxometalates (POMs)-based electrochromic smart windows have been fabricated. By adjusting the structure of the Dawson-type POM, it can be found that mono-vacant lacunary Dawson-type POM-based smart window has remarkable performance. For example, the maximum optical contrast 93.1% at the wavelength of 620 nm; the coloration time extracted for a 90% transmittance is 0.90 s; and the coloration efficiency is 205.3 cm2 C−1. The near-infrared electrochromic behaviors of the POMs have been investigated for the first time.