Printed Multifunctional Devices for Energy Harvesting, Cooling, and Sensing

The increasing demand for multifunctional and sustainable energy and sensing systems has driven the need for devices that can sense, harvest energy, provide cooling without harmful refrigerants, and operate reliably under extreme conditions. This dissertation establishes a unified framework for additive manufacturing of high-performance sensors, thermoelectric materials, and devices for power generation and cooling, as well as integrated self-powered sensing systems. Aerosol jet printing of gold and indium tin oxide (ITO) nanoparticle inks was used to develop multimodal sensors for simultaneous strain and temperature sensing, with a gauge factor of ~2.5, thermopower >55 µV/°C, and thermal stability up to 700 °C. Ultrafast photonic sintering enabled flexible sensors printed on polymer substrates with reproducible performance and negligible degradation under bending, twisting, and thermal cycling. Integrated thermocouples provided in-situ temperature compensation, enhancing strain measurement accuracy. Scalable ink-based processing strategies were developed for thermoelectric materials and devices, yielding silver selenide films with a power factor of 2.8 mW m?¹ K?² and a room-temperature zT of 0.99, while fully printed 3D devices delivered a power density of 84.3 mW cm?² at a 90 °C temperature gradient. Complementary bismuth-antimony-telluride-based devices fabricated by blade coating technique achieved efficient power generation with ultrahigh power density of 0.88 W cm?² at ?T of 175 °C and active cooling (?T up to 74 °C), enabled by a high zT of ~1.3 and optimized electric contact processing. Flexible thermoelectric devices further maintained stable performance under repeated bending, demonstrating the feasibility of wearable thermal management, energy harvesting, and self-powered sensing for health monitoring. Finally, high-temperature thermoelectric generators were integrated with printed sensors to realize self-powered structural health monitoring systems operating reliably above 500 °C, enabling precise strain and temperature measurements with long-range data transmission. This integration offers a practical pathway toward autonomous structural health monitoring and low-maintenance industrial sensing networks. Together, this work establishes a versatile and scalable approach for additive manufacturing of multifunctional devices, bridging sensing and energy harvesting. The outcomes provide a foundation for next-generation energy-autonomous devices that are flexible, miniaturized, self-powered, and capable of operating in extreme environments, with applications spanning wearables, IoT, energy-efficient electronics, and industrial monitoring.<p></p>