The focus of this research is to explore high-efficiency thermoelectric materials, which can be put into daily application to mitigate the energy crisis. Some fundamentals and modern characterization techniques are briefly discussed.
Due to their ability to convert waste heat into electricity, thermoelectric materials have drawn significant attention in the past two decades. The most widely used thermoelectric materials nowadays are still composed of Pb and Te. Due to the toxic nature of Pb, extensive work has been done on the GeTe system, an environmentally friendly replacement for PbTe. Unfortunately, the pristine GeTe suffers from a high carrier concentration originating from the low formation energy of Ge vacancies. Herein, the introduction of ZnO nanoparticles into the GeTe matrix to form ZnTe nanophase resulted in the suppression of carrier concentration. This simultaneously increased the average Seebeck coefficient by 40% and achieved a substantial reduction (33%) in electrical thermal conductivity below 600K when compared to a pure GeTe. As a result, the peak zT reached 1.44 at 690K in the 1.5wt.% ZnO sample, and an average zT value was increased by 23% to 0.79 in the 323-733K range.
By adopting partial substitution of Fe at the Co site in the Co4Ge6Te6 ternary skutterudites, Co4-xFexGe6Te6 (x=0.04 and 0.12) was successfully tuned from an n-type material into a p-type one as proven by the positive Seebeck coefficient. An enhanced electrical conductivity was achieved by increasing the carrier concentration. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/27913 |
| Date | January 2022 |
| Creators | Huang, Leon |
| Contributors | Mozharivskyj, Yurij |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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