Polymer-fullerene blend systems have found relevance and application in a number of fields including organic photovoltaic devices. While synthesizing new materials with desirable electronic properties is essential to designing better photovoltaic devices, it is equally important to understand the complex phase morphology of these blends and its effect on device performance. Consequently, this knowledge could be used to further design new materials and device architecture for more efficient systems. In particular, this dissertation focuses primarily on the morphology in a series of amorphous as well as semi-crystalline polymer-fullerene blend systems both in bulk and thin films and its relation to device performance. Scattering based techniques have been used to determine in-plane and out-of-plane phase morphology. Morphological parameters derived from these studies have shown possible correlation between fullerene segregation and device performance values. The results of these studies have been used to synthesize a thermo-cross-linkable fullerene acceptor having slower diffusion through the polymer, allowing better control of the polymer-fullerene blend morphology. Consequent effects have been studied on device lifetime and thermal stability and have shown significant improvements

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

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This dissertation uses syntactic, semantic and morphological evidence from English nominalization to probe the interaction of event-structure and syntax, develop a typology of structural complexity within nominalization, and test hypotheses about the strict ordering of functional items. I focus on the widely assumed typology of nominalization found in Chomsky (1970). In particular, I show that derived nominals are structurally more complex than nominal gerunds; this has long been assumed to be the opposite. I provide a structural and morphological account of these forms of nominalization. In doing so, I explore a number of disparate topics such as: the importance of syncretism in apparently unrelated morphological elements for theories like Distributed Morphology; the role of prepositions in allowing or preventing binding relations and NPI-licensing, the exact nature of root-object union that allows idiomatic interpretations; the morphological reflexes of Case in the nominal system; the syntactic structure of verb particle constructions; the nature of events in nominalization; and the role syntactic operations play in determining morphological regularity. The dissertation also explores the nature of the English verb particle construction, arguing that it has (at least) three distinct structural configurations. Using these three distinct structures I am able to explain a number of distinct behaviors from predicate-object relationships, particle modification and argument loss in particle construction. I also discuss the relationship between particles (and results) and the different forms of nominalization. In particular, I show that apparent co-occurrence restrictions between nominal types and particles are not due to event-structure or other semantic restrictions. Rather, these differences are tied solely to the particular, idiosyncratic morphological properties of the constructions. The dissertation shows that certain functional projections may only appear once with a given root, but that there is some freedom of ordering of projections relative to the root in some cases. This work provides a window into the interaction between syntax and event structure as well as the nature of ordering within functional projections.

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