Hybrid systems and the role of the linker molecule in charge transfer heterostructures : a first principles study

Authors
Ciesler, Matthew
ORCID
Loading...
Thumbnail Image
Other Contributors
Meunier, Vincent
Shi, Sufei
Terrones, Humberto
Zhang, Shengbai
Issue Date
2022-12
Keywords
Physics
Degree
PhD
Terms of Use
This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute (RPI), Troy, NY. Copyright of original work retained by author.
Full Citation
Abstract
Hybrid systems are composed of materials like nanorods and sheets that have reduced dimensionality. These hybrid systems have the potential to revolutionize the way we harvest energy and design systems at the nanoscale. One such example---colloidal quantum dots---are a 0D material, and show remarkable properties useful for photovoltaics and photocatalysis. The ligand molecules that tether these QDs to another surface possess a role that is not well understood. In this thesis, first principles calculations are employed to study these hybrid systems. First, density functional theory is used to understand how a model linker molecule (cysteine) chemically links the QD to the surface. We find configurations for cysteine in various protonation states linked to CdSe(100) and CdSe(001) via a Monte Carlo simulation. Next, we investigate what effect this linker molecule has on the charge transfer between the QD and the surface using the novel three-way-heterostructure from the previous work. We find that the linker molecule, when interacting with both sides, undergoes an intramolecular charge transfer, and the resulting system has greatly enhanced charge transfer based on Marcus Theory. Then, a dynamical simulation of this heterostucture was performed using time-dependent DFT (TD-DFT) in order to explore how the ligand affect the charge transfer at the ultra-fast timescale. We find that the ligand molecule and increased ionic temperature, enhance the charge transfer at this timescale, and that electrons are preferentially transferred from CdS to MoS2 as band alignment would predict. Finally, the study of hybrid systems is brought to a twisted bilayer of 2-dimensional h-BN, where the possible Moire patterns are analyzed and enumerated, and then a study of intercalated transition metal defects is conducted.
Description
December 2022
School of Science
Department
Dept. of Physics, Applied Physics, and Astronomy
Publisher
Rensselaer Polytechnic Institute, Troy, NY
Relationships
Rensselaer Theses and Dissertations Online Collection
Access
Users may download and share copies with attribution in accordance with a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 license. No commercial use or derivatives are permitted without the explicit approval of the author.
Collections