Dynamics and Structure-Property Relationships in Organic Single Crystal Electrical Double Layer Transistors

Abstract

The goal of this dissertation is to gain a deeper understanding of the factors governing electrical double layer transistor (EDLT) performance. Specifically, the effects of ion structure on EDLT performance are examined in detail towards the end of this work (Chapters 7, 8, and 9). A deep understanding of structure property relationships is fundamental to both being able to design novel high-performance ionic liquids for EDLT applications as well as being able to choose an ideal ionic liquid for a targeted application. Ion structure is a crucial factor determining a wide variety of ionic liquid and EDLT properties with simple structural modifications leading to changes in many ionic liquid and device properties simultaneously. Chapters 1-4 provide background knowledge helpful for understanding the research presented in Chapters 5-8. Chapter 5 explores dynamics of electric double layer formation in ionic liquid-based devices and provides insight about the relevant time scales involved. Chapter 6 focuses on work done to study free charge in EDLTs through spectroscopic means. Chapter 7 explores the effects of ion volume on various EDLT performance metrics. Chapter 8 digs deeper into an interesting observation made in the work of Chapter 7 involving ion volume and EDLT threshold voltage ultimately leading to an examination of the effects of ion adsorption on threshold voltage. This work is but a drop in the bucket required to gain a thorough understanding of these exceedingly complex systems, and Chapter 9 covers the many avenues of continued research that exist.