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Size and Shape Control of Colloidal Al Nanocrystals for UV Plasmonics Applications

Thesis Defense

Graduate and Postdoctoral Studies

By: Michael McClain
Doctoral Candidate
When: Monday, April 3, 2017
10:30 AM - 12:30 PM
Where: Dell Butcher Hall
Abstract: Al nanocrystals are a cost-effective alternative to noble metal nanomaterials with their own unique plasmonic features throughout the UV, visible, and infrared spectrum. In the past two decades, generalized rules for nanocrystal growth have been established for noble metal nanocrystals, which can now be prepared in a large range of architectures, enabling the controlled synthesis of a variety of plasmonic nanostructures. In contrast, the synthesis of Al nanocrystals requires conditions where most surfactants and additives commonly utilized for nanoparticle size and shape control cannot be used. Here, I examine how the properties of Al nanocrystal growth- crystallinity, size and shape- can be influenced by interactions with solvent molecules. Ethers and amines coordinate to alane precursors, affecting crystallinity, size, and shape of the product nanocrystal in different ways. Ethers with multiple coordinating sites can polymerize precursor alanes, increasing the temperature necessary for their decomposition, ultimately resulting in smaller particles. Highly coordinated ethers and amines allow for predictably-shaped alane polymer formation, allowing for samples with high size and shape homogeneity. These findings provide a basis for designing Al nanostructures through precursor control, and open the door for shape-controlled nanocrystals from air- and water-sensitive precursors.