Research on high-performance flexible thermoelectric power generator fabrication

Abstract

This dissertation focuses on the fabrication of flexible thermoelectric power generator (TEG) module for waste heat recovery. For that purpose, various methods using organic and inorganic materials are suggested for flexible and high-performance TEG module fabrication. Thermoelectric power generator, which converts waste heat into electricity, is one of the promising energy harvesting devices. However, conventional bulk-type TEG module is economically infeasible due to its high cost per watt. Therefore, reducing the fabrication cost and improving the output power are highly required to have competitiveness in the market. In this thesis, we have studied low-cost TEG module fabrication using a screen printing technique. Using this method, it is possible to deposit over tens of micrometer film on a large substrate in a short period of time and form pattern without lithography process. That means the price competitiveness of the TEG module fabricated by this process is high due to feasibility of both mass production and fast fabrication process. Through the optimal annealing process, it has been found that the thermoelectric properties of screen printed thick films are comparable to conventional bulk materials. Furthermore, we have studied on fabrication of flexible TEG module for various applications. In fact, because many heat sources such as power stations, heating systems, motor vehicles, and even human body have arbitrary shapes, a flexible TEG module helps to have better thermal contact with the arbitrary shaped heat sources. In this thesis, various methods using organic and inorganic materials are suggested for flexible and high-performance TEG module. First, the flexibility of the TEG module was significantly improved without performance degradation by infiltrating poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) into the screen-printed thick film. Second, thermoelectric properties of PEDOT:PSS were enhanced by carrier concentration tuning using self-assembled monolayers (SAMs) for highly flexible TEG module. The each result demonstrates feasibility of flexible and high-performance TEG module. As further works, the studies on output performance enhancement of flexible TEG modules were conducted. To improve the output performance, structure modification and related element technologies were thoroughly developed.