Rapid microwave synthesis of mesoporous TiO₂ for electrochromic displays

The fabrication of paper quality electrochromic displays based on the viologen modified TiO₂ electrodes (Vio²⁺/TiO₂) requires a cost-effective, energy efficient and rapid synthesis of mesoporous TiO₂ with high yield in short reaction time. A straightforward and industrially viable process for the preparation of mesoporous nanocrystalline titania (meso-nc-TiO₂) for NanoChromics™ display device applications by the use of microwave synthesis is presented here. Spherical aggregates of meso-nc-TiO₂ were rapidly achieved using titanium butoxide, deionised water and common alcohols (isopropanol, ethanol and butanol) at comparatively low microwave power intensity (300 W) for 2 min irradiation. The material has been characterised by a range of different techniques such as XRD, Raman spectroscopy, SEM and BET surface area analysis. These materials possess surface areas up to 240 m² g^-1, which is significantly higher than similar traditional sol-gel or commercial samples. This meso-nc-TiO₂ prepared was used as the working electrode for an electrochromic display device with Sb doped SnO₂ as the counter electrode material on an ITO coated conducting glass. A working prototype of a NanoChromics™ display was successfully fabricated using this approach.