Electrochromic windows based on luminescent acrylate/ionosilicas

Poly(methyl methacrylate) (PMMA)-based composite films doped with lanthanide-doped sol-gel derived imidazolium-based ionosilicas (IS-Ln) were recently proposed as active layers of luminescent down shifting (LDS) layers, but subsequent work demonstrated also their potential as electrolytes for electrochromic devices (ECDs) with foreseen application in smart windows of energy-efficient buildings. Nevertheless, some challenges remained to be addressed in the latter devices, the most critical one being the poor solubility of PMMA in the ionic liquid used in the formulation of these materials. To avoid this drawback, in the present work we propose novel lanthanide-containing acrylate/ionosilicas (AC/IS-Ln, Ln = Tb3+, Eu3+). The transparent, homogeneous, and luminescent hybrid materials synthesized are characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, atomic force microscopy, contact angle measurements, ionic conductivity, and photoluminescence spectroscopy. Optimized samples are successfully employed as electrolytes in luminescent ECD prototypes. The ECD device doped with AC/IS-Eu shows good cycling stability with reproducible bleaching/coloring over 50 chronoamperometry cycles, high coloration efficiency (CE) values CEin/CEout in the visible (-89/+98 cm2 C-1), and near-infrared (-126/138 cm2 C-1) spectral regions, and outstanding memory effect. Novel lanthanide-containing acrylate/ionosilicas (AC/IS-Ln) were synthesized by sol-gel chemistry.An optimized AC/IS-Eu hybrid was successfully applied as an electrolyte in an electrochromic device prototype.The prototype device demonstrated excellent electro-optical performance (good cycling stability, high coloration efficiency, and outstanding memory effect).