Zero and two dimensional nanomaterials for biological and electronic applications
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Description
Silicon nanomaterials exhibit unique properties from those of bulk silicon based on quantum confinement effects created by the reduction in size to the nanoscale. These properties include a tunable band gap, elevated brightness, increased chemical stability and, resistance to photobleaching. The compatibility with organisms makes silicon nanoparticles model candidates for use in many biological applications, while the exploitation of the size-dependent quantum confinement effects has led to the development of a range of electronic applications for both silicon nanoparticles and nanosheets. The preparation and characterization of zero-dimensional silicon nanoparticles and two-dimensional silicon nanosheets and their relevance to biological and electronic applications is described in the proceeding dissertation. TEGylated silicon nanoparticles were produced in one step from the reactive high-energy ball milling of silicon wafers with synthesized triethylene glycol monomethyl monopropargyl ether. A new approach for purifying the functionalized silicon nanoparticles using a silica-gel column was developed. Surface characterizations and optical properties of the silicon nanoparticles were accomplished through various analytical methods. Nanoparticle size and size distribution were determined using TEM and DLS while confirmation of ligand attachment to the silicon surface was confirmed through XPS and FTIR. Multilayer silicene nanosheets were generated from the oxidation of calcium silicide with synthesized ferrocenium tetrafluoroborate. The two-dimensional nanosheets were produced via a redox assisted chemical exfoliation reaction in which silicon polyanion layers were exfoliated from calcium silicide. A visual color change from dark blue to bright orange aided in the recognition of the culmination of the synthesis reaction. Interplanar spacing values for the silicene sheets were detected by XRD, crystal lattice parameters found from SAED images, and nanosheet composition revealed by EDS. Finally, the synthesized triethylene glycol monomethyl monopropargyl ether was used to attempt to produce electronically conductive silicon nanoparticles containing 4-ethynylaniline. TEG and 4-ethynylaniline were ball milled with silicon wafers to produce functionalized nanoparticles; however, separation limitations were met during the processing of the nanoparticles prior to characterization.