Chiral molecule sensing has important biochemical applications for detection of disease, as well as cognitive and neurodegenerative disorders. Circular dichroism (CD) has emerged as a powerful spectroscopic tool for probing post-synthetic ligand exchanges of chiral molecules onto originally achiral quantum confined CdS morphologies, manifesting in chirality corresponding to the electronic transitions of the nanocrystals. In this work, we first describe making water soluble quantum dots (QDs) and nanorods (NRs) via ligand exchange with glycine. After this exchange, aqueous chiral thiol solutions are then titrated into glycine capped achiral CdS, and the optical properties are monitored via UV-vis, photo-luminescence (PL), and CD spectroscopies. Preliminary results show we can controllably produce measurable chirality equal to or exceeding previous literature values whilst using orders of magnitude less L-cysteine than previously reported. Moving forward, we intend to correlate growth in CD with changes in PL across a myriad of cysteine derivatives. Additionally, we plan to examine the impact of NR aspect ratio on normalized maximum CD absorption (g-factor).   

Erbium(III) doped cerium oxide nanocrystals are promising candidates for spin qubits in quantum computing and information science applications. Our goal is to tune the synthesis and composition of Er-doped CeO2 nanocrystals for monodispersity and desirable optical properties, particularly the intensity and lifetime of near-infrared emission features unique to Er3+. We optimized previously reported methods for making Er-doped CeO2 by altering the concentration of erbium, presence of water, and the amount of time allowed for the reaction to progress. These nanocrystals were then analyzed using several techniques, including transmission electron microscopy, X-ray diffraction, and photoluminescence spectroscopy. Our results indicated that by omitting water from the synthesis, the sizes of the nanoparticles decreased significantly. Additionally, smaller concentration of erbium(III) dopant in the nanoparticles correlated with a longer lifetime of photoluminescence intensity.

Indium phosphide (InP) quantum dots are a high-performing semiconductor material used in optoelectronic applications due to their tunable electronic properties and low toxicity compared to cadmium-based quantum dots. However, InP quantum dots are currently synthesized at or above 180°C because of the high energy input required for nucleation and growth of the covalent nanocrystals. This study explores the synthesis of small InP clusters at lower temperatures by investigating reaction conditions that can produce InP with reduced energy consumption. Using the precursors indium carboxylate and P(SiMe₃)₃ in a nonpolar solvent toluene, we systematically investigate the evolution of InP clusters at room temperature and 60°C via UV-Vis absorbance spectroscopy. The formation of atomically precise InP clusters was observed at room temperature after 23 days. To speed up the reaction, we investigate adding a polar aprotic solvent or amines to promote the formation of InP at low temperatures. Including 20% of N-Methylpyrrolidone in the solvent mixture with toluene allows InP to be formed in 2 hours. Amine additives interact with the indium cations to modulate their reactivity, therefore we investigate adding varying equivalents both to the pre-formed atomically precise cluster, and to the indium and phosphorous precursors in toluene. We found that adding up to 100 equivalents of benzylamine per cluster did not promote the growth of InP clusters. Our findings contribute to the understanding of how InP forms at low temperatures for scalable, environmentally friendly production.

Morphological control in nanocrystal synthesis is crucial for tailoring material properties in magnetic, thermoelectric, catalytic, and renewable energy applications. In this study, we explore the synthesis of anisotropic single-phase Cu2Se nanorods (NRs) via cation exchange from CdSe NRs. Transmission electron microscopy and X-ray diffraction were employed to characterize the resulting nanocrystals. The synthesis of Cu2Se NRs remains challenging due to limited Se precursors suitable for shape control and identifying the kinetic conditions that lead to morphological selectivity. We have since shifted our focus to reaction conditions required to perform Cd-to-Cu cation exchange. Our work aims to refine synthetic parameters, including solvent compositions, hot injection temperatures, and concentration of Cd precursor to establish a reliable pathway for monodispersed nanorod formation and demonstrate precise morphological control. These insights will contribute to the Cossairt Lab’s broader efforts to advance nanoparticle synthesis for classical and quantum light emission, catalysis, renewable energy, and magnetooptical technologies.