Thermal Transport in Self-assembled Nanostructures by Ian Pearson Blitz Thesis

Understanding of phonon mediated thermal transport properties in nanostructured materials is essential for the intelligent design of next-generation microelectronic and thermoelectric devices. Presented here is the study of the thermal transport properties of model organic-inorganic, nanoscopically layered systems for the purpose of elucidating the dependence of bulk thermal conductivity on the nanostructure of the material and, specifically, the role that limited interfacial thermal conductance plays. We measured the bulk thermal conductivity of various organically modified montmorillonite clays as a function of several variables. Thermal conductivities of the organically modified clays were measured to be approximately 0.09 W/mK and were relatively independent of the variables investigated. This suggests the dominance of the organic-inorganic interfacial conductance in the determination of bulk thermal conductivity of this system and was determined from the thermal conductivity measurements to be approximately 150 MW/m 2 K, which is consistent with measured interfacial conductance in similarly coupled systems. Organic-inorganic perovskite structures were also investigated to determine the effect that varying crystal structure plays in determining thermal bulk thermal conductivity. While the data is too sparse to draw strong conclusions, current data suggests little dependence on the subtle changes in the crystal structure observed here. However, further study of this system may be warranted. iii ACKNOWLEDGEMENTS