Responsive Nanostructured Optical Materials

Live @ NCSU Daniels Hall #327 & Video Streaming @ Schiciano BNanostructured materials with optical properties responsive to external stimuli are gaining increasing interests due to their intrigue potential applications in printing, sensing, signage, security documents, displays, and other color related devices. In this presentation, I will first discuss our recent progresses on the development of chemical approaches for the fabrication of various nanostructured materials whose optical properties can be dynamically tuned by controlling the spatial arrangement of the nanoscale building blocks. We also show that many novel optical materials could be developed by manipulating the diffraction, refraction, birefringence, and electronic resonances such as surface plasmon through controlling the interaction between light and the nanostructures of dielectric and metallic materials. My discussion will then be focused on our very recent development of a new color switching system based on reversible redox reactions that could be initiated by photocatalytic response of TiO2 nanocrystals. With the assistance of TiO2-based photocatalysts, UV light irradiation can effectively reduce the redox dyes and result in rapid color change, while recoloration can be achieved by re-oxidizing the system with the assistance of visible light irradiation or heating.