By monolayer coverage of highly acidic semiconductors, such as MoO 3 and WO 3 on the surface of TiO 2 nanoparticles (Degussa P25), the stability of colloidal suspensions in aqueous solution can be greatly improved. The average diameter of agglomerated MoO 3 /TiO 2 and WO 3 /TiO 2 particles in aqueous suspension is only 85-110 nm, respectively, which is about one-fifth to one-fourth of that of pure TiO 2 suspension. The optically transparent photocatalytic films have been prepared with deposition of these colloidal suspensions. The colloidal particles in aqueous solution and the prepared transparent photocatalytic films were characterized with TEM, SEM, AFM, and other spectroscopic techniques. It has also been found that the photocatalytic activity of WO 3 /TiO 2 film is 2.8-3 times that of pure TiO 2 film in decomposing gas-phase 2-propanol, while MoO 3 /TiO 2 film is less effective.

Recent advancements in electronic packaging and image processing techniques have opened the possibility for optics-based portable eye tracking approaches, but technical and safety hurdles limit safe implementation toward wearable applications. Here, we introduce a fully wearable, wireless soft electronic system that offers a portable, highly sensitive tracking of eye movements (vergence) via the combination of skin-conformal sensors and a virtual reality system. Advancement of material processing and printing technologies based on aerosol jet printing enables reliable manufacturing of skin-like sensors, while the flexible hybrid circuit based on elastomer and chip integration allows comfortable integration with a user's head. Analytical and computational study of a data classification algorithm provides a highly accurate tool for real-time detection and classification of ocular motions. In vivo demonstration with 14 human subjects captures the potential of the wearable electronics as a portable therapy system, whose minimized form factor facilitates seamless interplay with traditional wearable hardware.

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