Reversible self-powered fluorescent electrochromic windows driven by perovskite solar cells

Self-powered electrofluorochromic devices (EFCDs) have attracted particular attention for smart windows of green buildings. In this work, we report a perovskite solar cell (PSC) driven self-powered EFCD. For the first time, electrochromic material polyoxometalates (POMs) and a fluorescent component are made into wet adhesives. A special design feature is that POMs and magnesium composed a battery powering the EFCD bleaching, and the device can be quickly coloured after connecting with the PSCs by the electrical power generated through solar energy conversion. Therefore, without any additional external bias, the fabricated EFCD undergoes an electrochromic transition from white semitransparent to dark blue-tinted, and under UV it presents reversible fluorescence switching between yellow and dark.