Wearable thermoelectric power generator

Abstract

The conversion of body heat into electrical energy by a thermoelectric (TE) power generator is useful for self-powered wearable mobile electronic systems. Especially, flexible thermoelectric generators (f-TEGs) are emerging as a semi-permanent power source for self-powered sensors, which is an important area of research for the next generation smart network monitoring systems in the Internet-of-things (IoT) era. However, previously reported organic-based flexible TE generators generate low output power that is far below the requirements for wearable electronic devices. Given such reason, researchers have studied submicron or micron scale inorganic thin films due to high power density and flexibility using conventional semiconductor devices processing tools such as DC magnetron sputtering, co-evaporation, or electrodeposition. However, the thin-film thermoelectric device is not able to generate sufficient electric energy for powering the wearable electronic systems due to very low temperature difference across the TE thin film. In addition, conventional TE generators usually have a relatively thick and bulky polymer or ceramic substrate, which causes serious thermal energy loss and limits the flexibility and output. This dissertation focuses on a device design and process development for fabricating a high-performance flexible thermoelectric generator that has high output power density but also excellent flexibility and mechanical stability, to overcome the limitations of commercial bulk-type TEG, and scale-up of the wearable power generator for improving electrical power generation on human body and heat sources. Screening printing technique: synthesis of Cu and TE pastes and subsequent annealing process, novel device design for a high power and flexible device, laser multi-scanning process and ionized defect engineering of a high-performance screen-printed TE thick film will be discussed.