|Name||Ms. Zon Thwin|
|Organization or Institution||University of Central Florida|
A Top-down Approach to Create ZnO Shell on the ZnS:Mn/ZnS Nanoparticles
Zon Thwin1,2,3, Ali Ozcan1,2, Tyler Maxwell1,2, Swadeshmukul Santra1,2,4,5
University of Central Florida
Hualongbing (HLB), also called citrus greening has seriously affected citrus production across the world. It is caused by a vascular system residing bacterium, Candidatus Liberibacter asiaticus. Copper pesticides that are used to control the agricultural diseases, does not travel systemically, and the repeated use of Cu has caused resistance and accumulation in soil. To effectively kill the bacteria, systemic pesticides are required. To become systemic, the pesticides has to be less than 5.4nm to be able to translocate freely through the plant vascular system. Zinc oxide nanoparticles (ZnO NPs), due to their small size and antimicrobial property, have shown potential to overcome these limitations. However, there is a great need to understand the fate and translocation of ZnO nanoparticles in the plant system to control the development of resistance. In this work, to study these ZnO NPs behavior, we present a surrogate molecule with fluorescent property having ZnO surface state. NPs with comparable size and surface properties have similar interactions within the plant system. The surrogate molecule is created by etching of highly fluorescent ZnS:Mn/ZnS NPs with hydrogen peroxide which oxidized the shell to form ZnO surface. The preservation of core structure and fluorescence enhancement, and ZnO surface defect state formation was confirmed by UV-Vis and Fluorescence Spectroscopy. Further characterization of ZnO shell formation will be performed using TEM, XRD, and XPS.