(558d) Advanced Nanocomposite Fibers for Thermoelectric Energy Harvesting and Motion Sensing

In this presentation, we will discuss nanocrystal coated fiber based devices for thermoelectric energy harvesting from waste heat and the conversion of air movement (including wind as well as air flow created by motion). In addition, we will show that these devices are capable to detect an extremely small temeprature fluctuation created by motion, which could find many defense and civilian applications. We will also describe our investigations on the thermal conductivity in the axial direction of a single glass fiber coated with lead telluride (PbTe) nanocrystals using the self-heated 3ω method particularly at low frequency. While prior 3ω measurements have only been demonstrated for high thermal conductivity materials, the present work demonstrates the suitability of the 3ω method for PbTe nanocrystal coated glass fibers where the low thermal conductivity and high aspect ratio result in a significant thermal radiation effect. We simulated the experiment using a finite-difference method that corrects the thermal radiation effect and extract the thermal conductivity of a single glass fiber coated by PbTe nanocrystals to be 0.32-0.46 W/mK in the temperature range 260 K-300 K. This process of including both an experimental approach and numerical modeling could be used to study the intrinsic thermal conductivity of other one-dimensional nanowire or nanotube samples with low thermal conductivity at the single wire/tube level, thus significantly broadening the application of the 3ω measurement technique.