Solution-Processed All-Solid-State Electrochromic Devices Based on SnO2/NiO Doped with Tin

We investigated the photochromic (PC) and electrochromic (EC) properties of tin-doped nickel oxide (NiO) thin films for solution-processable all-solid-state EC devices. The PC effect is shown to be enhanced by the addition of Sn into the precursor NiO solution. We fabricated an EC device with six layers—ITO/TiO2 (counter electrode)/SnO2 (ion-conducting layer)/SiO2 (barrier)/NiO doped with tin (EC layer)/ITO—by a hybrid fabrication process (sputtering for ITO and TiO2, sol–gel spin coating for SnO2 and NiO). The EC effect was also observed to be improved with the Sn-doped NiO layer. It was demonstrated that UV/O3 treatment is one of the critical processes that determine the EC performance of the hydroxide ion-based device. UV/O3 treatment generates hydroxide ions, induces phase separation from a single mixture of SnO2 and silicone oil, and improves the surface morphology of the films, thereby boosting the performance of EC devices. EC performance can be enhanced further by optimizing the thickness of TiO2 and SiO2 layers. Specifically, the SiO2 barrier blocks the transport of charges, bringing in an increase in anodic coloration. We achieved the transmittance modulation of 38.3% and the coloration efficiency of 39.7 cm2/C. We also evaluated the heat resistance of the all-solid-state EC device and found that the transmittance modulation was decreased by 36% from its initial value at 100 °C. Furthermore, we demonstrated that a large-area EC device can be fabricated using slot-die coating without much compromise on EC performance.

Morphological Analysis of Ag Doped on TiO2/Ti Prepared via Anodizing and Thermal Oxidation Methods

In this work, we present the morphology analysis of TiO2/Ti prepared via anodizing and thermal oxidation (TO) methods and doped by Ag-TiO2 sol-gel nanocomposites through liquid phase deposition (LPD) technique. The comparative morphology of both semiconductors has been observed to inform the catalysis preparation for better morphology structures to the photocatalytic performance. Based on these results, we report that the TiO2/Ti prepared via anodizing method exhibits TiO2 nanotubes arrays (TNTAs) formed like honeycomb structures, while the TiO2/Ti TO (TTO) has diverse size structures. The neat arrangement of TNTAs has a larger surface area and pore volume than TTO structures, which can expose more adsorption and reaction sites, resulting in higher catalytic activity. Uniquely, both semiconductors, after coated by Ag-TiO2 sol-gel, show lamellar sediments covering the surface of TNTAs and TTO. We believe that the anodizing method is a good ability for photocatalysis compared with TTO in terms of small surface area and nanosize structures.

High Flame Retardant Performance of SiO2-TiO2 Sol Coated on Polyester/Cotton Fabrics

SiO2 and TiO2 sols were successfully synthesized by using sodium silicate and titanium chloride as Si and Ti sources. SiO2-TiO2 sol coated polyester/cotton fabric was fabricated by deep-coating method and using SiO2, TiO2 sols as coating materials. SiO2-TiO2 coated fabric were characterized by XRD, FTIR, TGA, SEM and EDX. From SEM image, it showed the SiO2, TiO2 particles of 20-30 nm which well deposited on fabric surface. TGA result revealed the significant improvement of thermal resistance and stability of SiO2-TiO2 coated fabric as compared to those of uncoated fabric. Flame retardant performance of SiO2-TiO2 coated fabrics was much better than that of uncoated fabric. Thus, SiO2-TiO2 coated fabric SiO2-TiO2 content of 26wt% showed the UL-94 classification of V-0 and LOI value of 30.3 were obtained. Moreover, mechanical property (tear strength) of SiO2-TiO2 coated fabrics were also improved.

On the Use of a TiO2 Sol-Gel for Horseradish Peroxidase Enzyme Immobilization for Development of an Amperometric Biosensor

The sol-gel technique has drawn considerable attention in the area of biomolecules immobilization by virtue of its intrinsic properties including chemical inertness, thermal stability, and good biocompatibility. The present work reports the development of a bio-sensing methodology which involves the immobilization of horseradish peroxidase enzyme (HRP) on pencil graphite electrode (PGE) using TiO2 sol-gel and its application for 5-aminosalicylic acid (5-ASA) determination in pharmaceutical formulations. TiO2 sol-gel film was deposited on the PGE surface by dip coating, and the HRP enzyme was immobilized on the film by adsorption and cross-linked binding using glutaraldehyde. The analytical performance of the methodology was investigated through amperometric measurements at –0.08 V in the presence of 5-ASA (electron mediator) and hydrogen peroxide (substrate). The biosensor was successfully applied for 5-ASA determination, where limits of detection and quantification of 3.3 and 10.0 μmol L-1, respectively, were obtained. The application of the methodology for 5-ASA determination in pharmaceutical formulations led to satisfactory recovery rates ranging from 80 to 98%. The biosensor developed in this work is simple, inexpensive and has the potential to be applied for the determination of other pharmaceutical compounds, which also act as electron mediators in the catalytic cycle of HRP.