Item Details

title

Molecular Rectifiers: Design and Applications

author

Sullivan, Ryan Patrick

abstract

The field of molecular electronics is an interdisciplinary field that includes physics, materials science, chemistry and engineering which uses small molecules as the basis for electronic components. The large potential of molecular devices stem from their self-assembled device structures offering unrivaled cost-efficiency at nanoscales with extensive scalability to ultimately supply alternatives to silicon-based electronic devices as well as their excellent chemical diversity, which can lead to the development of many different devices for novel applications. In molecular electronics, commonly used metal/molecule/metal device structures offer excellent testing platforms for investigating charge transport mechanisms in organic molecules and at molecule-electrode interfaces. The work contained in this thesis focuses on furthering the understanding of the fundamental charge transport mechanisms in one of the simplest molecular devices: the molecular rectifier, where we explore novel methodologies to enhance its electrical performance as well as to diversify its functionalities. This work encompasses the usage of novel organic materials and spans from device design to characterization to the development of new theoretical models. This research specifically focuses on utilizing devices based on molecular rectifiers for the novel application of sensing humidity both reproducibly and reversibly over a wide humidity range. Additionally, we focus on improving the modeling of molecular rectification mechanisms in molecular ensemble junctions by including the often overlooked Stark effect as well as treating the number of conducting molecules in the junction as a function of bias. We also introduce a method of enhancing rectification by exploiting new electronic states within mixed self-assembled monolayers through a novel process of intermolecular charge transfer. Lastly, we investigate the temperature dependencies of charge transport in these devices which highlights the intricacies of coherent and incoherent tunneling mechanisms and brings forth evidence that entropic effects contribute to high-performance molecular rectification.

subject

Charge Transfer

Charge Transport

Molecular Electronics

Molecular Rectifiers

Molecular Sensors

Self-Assembled Monolayers

contributor

Jurchescu, Oana D (advisor)

Srimath Kandada, Ajay Ram (committee member)

Salsbury, Fred (committee member)

Winter, Stephen M (committee member)

date

2024-02-13T09:36:23Z (accessioned)

2023 (issued)

degree

Physics (discipline)

embargo

2025-02-12 (terms)

2025-02-12 (liftdate)

identifier

http://hdl.handle.net/10339/102918 (uri)

language

en (iso)

publisher

Wake Forest University

type

Dissertation