Award Date

5-2011

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry

Department

Chemistry

First Committee Member

Dong-Chan Lee, Chair

Second Committee Member

Clemens Heske

Third Committee Member

Kathleen Robins

Graduate Faculty Representative

Michael Pravica

Number of Pages

157

Abstract

Current demands in the area of organic semiconductors focus on both electronic and self-assembling properties. Particularly, one-dimensionally grown nanostructures of small organic semiconductors have drawn much attention for nanodevice fabrication. Self-assembly through various intermolecular interactions has been widely used to produce one-dimensionally grown nanostructures which can be induced by various methods such as rapid solution dispersion, a phase transfer method, vapor annealing, crystallization, and organogelation in conjunction with proper molecular design. Controlling the morphology of the nanostructures plays an important role in achieving desirable properties in optoelectronic device applications. While significant advancements have been made in developing molecular architectures for successful molecular assembly, most of the reported examples are for electron-donating (p-type) organic semiconductors, with only a limited number characterized as electron-accepting (n-type). Consequently, developing useful n-type organic semiconductors with a self-assembling ability is of critical importance.

The objective of this research is to create a new n-type organic semiconductor which can self-assemble into one-dimensional nanostructures. A series of T-shaped asymmetric bisphenazine derivatives containing different functional groups were designed and synthesized in order to investigate the effect of the position, type, and number of substituents on electronic and assembling properties. Furthermore, phenazine and bisphenazine substituted with four chlorines for increasing electron density at one end and alkyl side groups for increasing solubility at the other end were also synthesized. The final compounds were fully characterized with 1H NMR, 13C NMR, and mass spectrometry. The electronic properties were studied by UV-visible absorption and emission spectroscopy, and cyclic voltammetry. The experimental values for the electronic properties of these systems are compared with theoretical calculations. The assembling properties were also extensively investigated by polarized optical microscopy, scanning electron microscopy, atomic force microscopy, single crystal X-ray crystallography, and X-ray diffraction.

Keywords

Bisphenazine; Electronic property; N-type; Organic semiconductors; Phenazine; Self-assembly; Self-organizing systems; Synthesis

Disciplines

Chemical Engineering | Chemistry | Electronic Devices and Semiconductor Manufacturing | Nanoscience and Nanotechnology | Organic Chemistry | Physical Chemistry

Language

English