Dithienopyrrole-based conjugated materials, including oligomers and polymers, for potential organic electronic applications, were designed, synthesized and characterized. The optical and electrochemical properties of these materials were investigated, and their structure-property relationships were studied. Some of the materials can be oxidized (or reduced) chemically or electrochemically. Furthermore, the utility of these materials in organic electronic devices, such as OFETs and OPVs, were assessed. In OFETs, they can function as hole-transport materials with mobilities up to 4.8 × 10-2 cm2/(Vs), and one example serves as an ambipolar material with comparable hole and electron mobilities of 1.2 × 10-3 and 5.8 ×10-4 cm2/(Vs), respectively. Some of the materials can also be used as electron donors in OPVs in conjunction with PCBM, and exhibited power conversion efficiencies up to 1.4% after optimizations. They may also be used in other applications such as electrochromic devices, photodetectors, and optical limiting.

The field of molecular electronics includes the study of conjugated oligomers and polymers that have significant potential for use in devices such as light emitting diodes (LEDS), field effect transistors (FETS), and photovoltaic solar cells. These materials may replace inorganic semiconductors in these devices, Achieving better device performance through lowering the band-gap and achieving higher field effect mobilities will benefit from a greater fundamental understanding of charge transfer through the aromatic subunits. π-stacking of segments of conjugated polymers has been identified as a key feature that influences the charge transfer through semiconducting organic materials. Optimizing the molecular architecture of conjugated polymers has the potential to provide materials with better charge mobility. While devices might benefit from materials that take advantage of π-stacking, access to π-stacked structures presents a synthetic challenge. 1,8-Disubstituted naphthalenes may serve as simple covalent bridging scaffolds which might hold conjugated oligomers in a π-stacked arrangement. The research described in this thesis focuses on the synthesis of well-defined phenylene ethynylene oligomers coupled to naphthalene to serve as experimental models of closely π-stacked aromatic units in conjugated polymers. The π-stacked molecules reported in this dissertation are characterized by NMR, IR, and mass spectrometry. The effects of π- stacking on the structure and behavior of conjugated oligomers are determined by X-ray crystallography, spectroscopy, and electrochemistry.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references. Also available in print.

Not available / text

Not available / text

No description available.

No description available.

In this work, organic solar cells of the configuration ITO/Pedot:PSS/CuPc/PTCBI/Al (Indium tin oxide/poly(3,4-ethylenedioxythiophene): polystyrene sulfonic acid/copper phthalocyanine/3,4,9,10-perylenetetracarboxylic bisbenzimidazole/aluminum) were investigated. A high open-circuit voltage (Voc) of 1.15 V was obtained when the PTCBI layer was 7 nm thick. Lower Voc values were observed for the same structure with silver, copper and gold electrodes instead of aluminum. However, short-circuit current density (Jsc) with these electrodes was much higher (4 mA/cm2) than in the case of aluminum (0.12 mA/cm2). Results were interpreted in terms of a modified CuPc/Al Schottky diode for the thin PTCBI case and a CuPc/PTCBI heterojunction for the thick PTCBI case. Also, the formation of a thin, protective aluminum oxide layer under the aluminum electrode was postulated. For devices with silver, copper and gold electrodes, absence of this protective layer was thought to be the cause of a relatively lower Voc and higher Jsc.

Research into conductive organic and organometallic polymers began in 1977 when Heeger, Macdiarmid, and Shirakawa first doped polyacteylene with Iodine. They found that this doping granted the polymer metallic properties increasing conductivity by 11 orders of magnitude.[1] Unfortunately, polyacteylene is highly air-sensitive making it difficult to work with and limiting its applications. Therefore, current research is focused on synthesizing new organic and organometallic conductive polymers. The drive to discover these new polymers stems from their application flexibility and their low production cost. Reported here is the synthesis of novel organometallic polymer precursors. Lead by Dr. Chad Snyder a library of chloro-phenyl based fulvenes, 5,6 fused ring pyridazines, and thallium Cp salts have successfully been synthesized. Research is currently underway to synthesize rhenium and manganese pyridazines through transmetalation of the thallium salts. The off-metal route of synthesis was followed as opposed to the previously reported on-metal route. Characterization was performed by 1H-NMR, 13CNMR, and IR. Additionally, research has begun on bromo-thiophene complexes. So far, bromothiophene fulvenes, pyridazines, and thallium Cp salts have been synthesized and work is currently underway to produced rhenium and manganese pyridazines as well. Characterization was performed by 1H-NMR and 13C-NMR.

Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request