Date of Award

12-24-2025

Date Published

January 2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor(s)

Mathew Maye

Second Advisor

Ethan Arnault

Subject Categories

Chemistry | Physical Sciences and Mathematics

Abstract

This dissertation investigates the design and synthesis of colloidal semiconductor heterostructures and superconducting materials, emphasizing how synthetic parameters control growth pathways, size, microstructure, surface morphology, magnetic response, and optical properties. Semiconductor quantum dots and quantum rods exhibit quantum confinement, which enables tunable light absorption and photoluminescence for light-emitting devices and sensors. CdSe QRs are used to study how the aspect ratio, shell composition, and the ligand environment regulate shell growth, morphology, and optical properties. By modifying the reaction conditions, both thick-shell deposition and overgrowth are analyzed, including the formation of ZnS nanorod assemblies templated by CdSe cores. High-temperature superconductors such as YBa2Cu3O7-x (YBCO) exhibit superconductivity above liquid nitrogen temperatures (77 K) and have applications in energy storage and transfer, as well as electromagnets. Using analogous synthetic techniques, a top-down processing method was developed, and a bottom-up synthesis route was investigated to prepare YBCO colloidal inks and nanopowders, respectively. Physical and chemical processing was used to produce colloidal inks that preserve the superconductor character of the processed substrate. These YBCO colloids were then integrated into poly(dimethylsiloxane) (PDMS), enabling the formation of various-shaped composites with adjustable magnetic properties and flexibility for the purpose of developing new devices and applications. Surfactant-directed micellar assembly was used to form a precursor nanopowder, followed by high-temperature calcination, to form the superconducting crystal phase in YBCO grains with diameters of 100-300 nm. Experimental samples in both routes exhibit changes in magnetic moment and critical temperature, relative to the prepared solid-state YBCO, highlighting tunable nanoscale/colloidal methods that can be extended to related materials and used to prepare new superconductor-composite materials.

Access

Open Access

Available for download on Saturday, January 16, 2027

Included in

Chemistry Commons

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