This Faculty Early Career Development (CAREER) grant integrates advanced materials and manufacturing techniques to create next-generation energy devices. Advanced manufacturing of energy materials and devices has the potential to transform the energy efficiency landscape. Over fifty percent of energy resources are wasted as heat. Thermoelectric device, which convert a temperature change to a voltage change, convert heat directly into electricity, and can dramatically improve energy efficiency and enable distributed electricity generation. To put these materials into widespread use, a manufacturing approach that enables effective materials engineering and integration as well as customizable device design is needed. Additive manufacturing, particularly laser-based additive manufacturing, presents a potential solution to enable widespread thermoelectric device fabrication. Very little is known, however, about how laser processing in Additive Manufacturing (during which materials rapidly melt and re-solidify) impacts thermoelectric materials' structure and properties. This research project aims to uncover the relationship between rapid melting and solidification and the resulting nano-, micro-, and meso-scale structures, and understand the impact of these structures on thermal and electrical properties of thermoelectric materials. The research is integrated with an educational and outreach approach that uses materials science, manufacturing, and energy engineering as a platform to broaden and diversify the engineering workforce and create educational and professional development experiences for a future workforce that is equipped to prosper in technology design, development, and deployment.
This project investigates how the interfaces created by laser processing alter the transport properties of thermoelectric materials. The project will examine whether the interface density resulting from laser-induced melting and solidification causes the thermal conductivity to decrease and the thermoelectric power factor to increase. Laser processing parameters determine the temporal and spatial variation of the temperature gradients, and these gradients determine what, where, and when interfaces form. The size, density, and location of those interfaces determine how they will impact energy carrier transport. The research approach is to experimentally and computationally investigate the process-structure-property relationship by (1) experimentally characterizing the multi-scale structures and properties and (2) modeling the time-varying, three dimensional temperature gradients along with the formation of microstructural crystalline morphologies. The project focuses on interfaces in the form of grains, dislocations, phase segregation, and point defects. This work enables laser processing to engineer interfaces (and thus control energy carrier transport) in semiconductor materials, and it advances laser powder bed fusion from a manufacturing technology limited mostly to metals to one that includes semiconductors–paving the way for additive manufacturing of new, multifunctional structures.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
