![]() This data suggests in situ illumination is a potential novel tool to manipulate device-relevant morphologies of optoelectronic active layers throughout the fabrication process, offering a cheap nondestructive tool to effectively tune desired structural parameters. More importantly, the extent of stratification varies with illumination, where exposure to white light increases stratification. Results indicate the formation of a nonhomogeneous blend upon casting, which becomes stratified with thermal annealing. In order to explore the structural evolution that occurs in the film formation of a blend composed of polystyrene and the benchmark conjugated polymer MEH-PPV, we have performed a series of neutron reflectivity experiments focused on studying the film structure as it changes through the thermal annealing process both in the presence and absence of white light. However, if properly understood and harnessed, these light-induced effects could make possible an entirely novel methodology for in-situ tuning of organic electronic device physical parameters.Due to its simplicity and cost-effectiveness, single solution casting of organic optoelectronics has grown in popularity for device fabrication to produce technologies such as organic photovoltaics and thin film transistors. Overlooking illumination conditions and failing to provide a consistent ambient light environment throughout device fabrication will result in non-uniform chain conformations and layering architectures, inevitably impacting device performance. Ultimately, these works cumulatively provide strong evidence indicating that light exposure is in fact an important parameter with far-reaching implications upon the final structure of organic electronic materials. ![]() Finally, the sixth section studies the self-assembly of conjugated polymer composite thin films cast from a single solution through neutron reflectivity, while additionally monitoring the effects of light exposure during the thermal annealing process upon the final film depth profile. Holiday decorations have changed (a lot) since the 80s and the Knoxville area has some amazing light displays that you just shouldnt miss Where To See. ![]() The fourth and fifth chapters further expand our understanding of the proposed thermodynamic driving forces behind the light induced structural changes in conjugated polymer solutions first through alterations in solvent quality, and then through fine-tuning of incident light wavelength, exposure time, and intensity. Flashes are either quick or long bursts of light. The third chapter explores the structural evolution of solution gels formed from conjugated polymers at multiple length scales using small and ultra small angle scattering, as well as quantifying modifications to this structural progression brought on by white light exposure. Floaters are more commonly seen when looking at a white background with bright, overhead illumination. The next section outlines an initial exploration of light induced effects on benchmark conjugated polymers in solution elucidated via the use of small angle neutron scattering. The first part of this dissertation provides a background to conjugated polymers, their role in common electronic applications, and the known effects of illumination on polymeric materials. Considering the strong link between polymer chain structure and device efficiency in these materials, a comprehensive understanding of certain experimental conditions which may influence this conformation and thusly alter the functionality of the devices predicated upon them is of vital importance. Conjugated polymers are an important class of optoelectronic polymeric materials which make up the active layer of key organic electronic devices such as organic photovoltaics, transistors, and light emitting diodes. This dissertation explores the effects which illumination has on the structure and conformation of conjugated polymers, both in solution and the bulk.
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