Date of Award

Spring 1-1-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Ivan I. Smalyukh

Second Advisor

Noel A. Clark

Third Advisor

Patrica Rankin

Fourth Advisor

David M. Walba

Fifth Advisor

Yifu Ding

Abstract

Nanostructure liquid crystal composites are perfect for designing novel materials with predefined properties that can be of substantial interest in many fields including materials science, electronics, optics, and energy storage. Liquid Crystals (LCs) are a good candidate to work as a host medium for nanoparticles with different properties given their low cost and facile responsive characteristic to external stimuli such as voltages as low as one volt. Concentrated dispersions of anisotropic gold, silver, and metal alloy nanoparticles in nematic hosts have been achieved and successfully controlled using low-voltage fields. However, to enable versatile designs of material behavior of these composites, simultaneous dispersion of anisotropic particles with different shapes, alignment properties, and compositions is often needed. For example, integrated plasmonic gold nanoparticles in the up-convergent nanoparticles (UCNPs) or quantum dots (QDs) semiconductor matrices serves as nano antennae that can harvest the light energy to the nanostructured matrix giving rise to potential applications. In this work, spectral characteristics of dispersions of multiple types of anisotropic nanoparticles in a common nematic host LC provide an unprecedented variety of electrically- and optically-tunable material behavior. Different composites of inclusions of plasmonic gold nanorods, quantum dots, dyes will be explored and implementing such composites in an inexpensive, energy-efficient, large-area, fast-switching smart windows applications, along with exploring different self-assembled systems by entropically driven forces will be discussed. Overall, utilizing LCs as a guest medium to these nanoparticles allows for unique features as well as promising properties through the design of novel self-assembly based hybrid nanostructures. This can give rise to potential and practical applications for the fabrication of optical or electro-optical devices such as climate dependent optimal solar gain smart windows, switchable plasmonic polarizers, and may expand to further satisfy renewable energy needs.

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