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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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School of Civil and Environmental Engineering
Ph.D. Thesis Defense Announcement
Visible to UV Upconversion Materials for Surface Disinfection and Photocatalyst Sensitization
by:
Stephanie L. Chinnapongse Cates
Advisor:
Dr. Jaehong Kim (CEE)
Committee Members:
Dr. John Crittenden (CEE); Dr. Ching-Hua Huang (CEE); Dr. Angus Wilkinson (CHEM), Dr. Sotira Yiacoumi (CEE)
Date & Time: April 3 @ 11:00am
Location: Mason 3133
Abstract:
UV radiation is utilized in a number of environmental technologies, most notably for the disinfection of water, air, and surfaces through the use of UVC fluorescent lamps. Recently, our group developed a luminescent material that could emit germicidal UVC simply by irradiating it with a household fluorescent lamp, thus introducing a new type of antimicrobial surface powered by low-intensity visible light. The materials were doped with praseodymium ions (Pr3+) which have the unique capability of converting visible light to higher energy UV using an optical mechanism called upconversion. While visible-to-UV upconversion materials appeared promising for environmental application --particularly because solar irradiation could be used for their activation --their practical application was thwarted by low light conversion efficiencies. Herein we discuss the pursuit of new material forms and modifications designed to improve the efficiency of Pr3+-based upconversion systems. These enabled successful enhancement of antimicrobial activity and led to a proof of concept for upconversion-sensitized TiO2 photocatalysis. Correlations between material properties and optical behavior will be presented, followed by commentary on how these strategies might be used to further advance upconversion systems toward environmental application.
