Graduation Year

2023

Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts

Department

Chemistry

Reader 1

Bethany Caulkins

Reader 2

Joel Mackey

Reader 3

N/A

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Rights Information

2022 Jessica J. Beyer

Abstract

The purpose of this work was to determine the impact of quantum dot size on ionization potential and to determine how the presence of carbonyl-based ligands affect the ionization potential of lead sulfide quantum dot systems. Ionization potential (IP) is defined as the energy required to remove an electron from an atom, molecule, or material. IP helps scientists determine how reactive the material of interest is, which is crucial information when manufacturing nanomaterials. Accurate quantum chemical calculations of ionization potential are challenging due to the computational cost associated with the numerical solution of the Dyson equation. In this work, the stratified stochastic enumeration of molecular orbitals method (SSE-MO) was used to address this challenge. IP was calculated using the SSE-MO method, a computational chemistry method that utilizes a combination of stratified sampling and stochastic enumeration to obtain IPs in an efficient and accurate manner. This method’s accuracy was confirmed on systems with known literature values before utilizing it to calculate the IPs of lead sulfide quantum dots. SSE-MO was used to calculate the ionization potentials of different sized lead sulfide (PbS) bare quantum dots, Pb4S4 and Pb44S44 monodentate (non-bridged) ligated systems, Pb44S44 bridged ligated systems, and Pb44S44 chelated ligated systems. The results obtained provide insight into the impact of quantum dot size and the presence of ligands on ionization potentials of PbS quantum dot systems, but further testing must be performed to gain more definitive information on the relationship between IP, quantum dot size, and ligand presence.

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