[CCoE Notice] Dissertation Announcement: Ali Rad, "New Chemistries for Cost-Effective Synthesis of Highly Fluorescent Zinc Selenide Quantum Dots using Air-Stable Zinc Precursors"

[Greenwell, Stephen J]

[Dissertation Defense Announcement at the Cullen College of Engineering]
New Chemistries for Cost-Effective Synthesis of Highly Fluorescent Zinc Selenide Quantum Dots using Air-Stable Zinc Precursors

Ali Rad

December 5, 2024; 2 p.m. - 3:30 p.m.
Location: Chemical Engineering Conference Room (S234), Eng. Bldg. 1

Committee Chairs:
Triantafillos J. Mountziaris, Ph.D.
Committee Members:
Jeffrey D. Rimer, Ph.D. | Alamgir Karim, Ph.D. | Mim Rahimi, Ph.D |
Richa Chandra, Ph.D
Abstract
Quantum dots (QDs) are semiconductor nanocrystals with remarkable optical properties, finding applications in optoelectronics, photovoltaics, and bioimaging. Zinc selenide (ZnSe) QDs are especially promising due to their tunable emission and high luminescence. However, traditional synthesis methods using diethylzinc as a zinc precursor pose significant challenges due to its pyrophoric nature, high cost, and stringent safety requirements.

This research presents a safer, more cost-effective synthesis approach by substituting diethylzinc with air-stable zinc precursors, such as zinc acetate and zinc chloride. By systematically optimizing reaction conditions, particularly through the strategic selection of co-solvents, we achieved high-quality ZnSe QDs with exceptional optical properties. Using butanol as a co-solvent with zinc acetate produced QDs with a quantum yield of approximately 50%, while a one-step injection method with zinc chloride and acetone achieved a remarkable 93% quantum yield.

Characterization techniques, including transmission electron microscopy (TEM), X-ray diffraction (XRD), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), ultraviolet-visible (UV-Vis) spectroscopy, and photoluminescence spectroscopy, confirmed the zinc-blende crystal structure, narrow particle size distribution, and effective surface passivation by hexadecylamine.
These findings highlight the role of co-solvent selection in optimizing QD growth and quality, as well as the potential of air-stable precursors to address safety and cost limitations. This work advances nanomaterials research, offering a scalable and efficient pathway for integrating ZnSe QDs into advanced optoelectronic applications.
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