Nigel Leyland

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.

Highly Efficient F, Cu doped TiO2 anti-bacterial visible light active photocatalytic coatings to combat hospital-acquired infections

Bacterial infections are a major threat to the health of patients in healthcare facilities including hospitals. One of the major causes of patient morbidity is infection with Staphylococcus aureus. One of the the most dominant nosocomial bacteria, Methicillin Resistant Staphylococcus aureus (MRSA) have been reported to survive on hospital surfaces (e.g. privacy window glasses) for up to 5 months. None of the current anti-bacterial technology is efficient in eliminating Staphylococcus aureus. A novel transparent, immobilised and superhydrophilic coating of titanium dioxide, co-doped with fluorine and copper has been prepared on float glass substrates. Antibacterial activity has demonstrated (by using Staphylococcus aureus), resulting from a combination of visible light activated (VLA) photocatalysis and copper ion toxicity. Co-doping with copper and fluorine has been shown to improve the performance of the coating, relative to a purely fluorine-doped VLA photocatalyst. Reductions in bacterial population of log10 = 4.2 under visible light irradiation and log10 = 1.8 in darkness have been achieved, compared with log10 = 1.8 under visible light irradiation and no activity, for a purely fluorine-doped titania. Generation of reactive oxygen species from the photocatalytic coatings is the major factor that significantly reduces the bacterial growth on the glass surfaces.

4.5: The Design and Driving of Active‐Matrix Electrochromic Displays Driven by LTPS TFTs

We have successfully driven a high-resolution (200dpi) QVGA active-matrix electro-chromic display (AMECD) with integrated driver electronics fabricated using low-temperature polysilicon thin-film transistor (LTPS-TFT) technology. This non-volatile reflective display requires low operating voltages, and possesses the advantages of high contrast ratio, sharp image quality, very large viewing angle and an image retention of a few days.