Summary Strategic Electr ategic Electronic Pr onic Property Contr ty Control of Self-Assembling P ol of Self-Assembling PyrazineAce

UNLV Theses, Dissertations, Professional Papers, and Capstones


5-1-2013

Strategic Electronic Property Control of Self-Assembling Pyrazine-
Acenes
Lacie Brownell
University of Nevada, Las Vegas




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Repository Citation
Brownell, Lacie, "Strategic Electronic Property Control of Self-Assembling Pyrazine-Acenes" (2013). UNLV
Theses, Dissertations, Professional Papers, and Capstones. 1807.
http://dx.doi.org/10.34917/4478203


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,STRATEGIC ELECTRONIC PROPERTY CONTROL OF SELF-

ASSEMBLYING PYRAZINE-ACENES




by




Lacie V. Brownell




Bachelor of Science in Biochemistry

University of Nevada, Las Vegas

2008



A thesis submitted in partial fulfillment

of the requirement for the



Master of Science in Chemistry



Department of Chemistry

College of Sciences

The Graduate College



University of Nevada, Las Vegas

May 2013

,THE GRADUATE COLLEGE


We recommend the thesis prepared under our supervision by

Lacie Brownell


entitled

Strategic Electronic Property Control of Self-Assemblying Pyrazine-Acenes


be accepted in partial fulfillment of the requirements for the degree of

Master of Science in Chemistry
Department of Chemistry

Dong-Chan Lee, Ph.D., Committee Chair

David Hatchett, Ph.D., Committee Member

Kathleen Robins, Ph.D., Committee Member

Monika Neda, Ph.D., Graduate College Representative

Tom Piechota, Ph.D., Interim Vice President for Research &
Dean of the Graduate College

May 2013




ii

, ABSTRACT

Strategic Electronic Property Control of Self-Assembling Pyrazine-Acenes

by

Lacie V. Brownell

Dr. Dong-Chan Lee, Exam Committee Chair
Associate Professor of Chemistry
University of Nevada- Las Vegas


Control of electronic properties in organic semiconductor materials is essential for

electro-optical applications such as field-effect transistors, light-emitting diodes, and

photovoltaic devices. This work is focused on two systems that highlight different

approaches for the manipulation of electronic properties: (I) the development of electron-

deficient (n-type) materials by selective lowering of ELUMO and (II) low energy gap

materials by controlling both ELUMO and EHOMO.

To specifically lower ELUMO, a pyrazine-acene π-platform was extended using

electron-withdrawing moieties. These include: pyridine, pyrazine, and benzothiadiazole

(system I). From the base pyrazine-acene, the most significant change in ELUMO of 0.83

eV was observed with benzothiadiazole π-extender, while pyridine and pyrazine lowered

ELUMO by 0.15 eV and 0.42 eV, respectively. EHOMO was relatively unaffected by these π-

extenders.

The mechanism for ELUMO control in this system was illustrated by theoretical

evaluation. We found that the LUMO orbital localized on the more electron deficient

part of the pyrazine-acene including the π-extenders, while the HOMO orbital localized

on the more electron rich portion, away from the π-extenders. This enabled us to achieve

specific control of ELUMO depending on the type of π-extenders.


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