Tid og sted for prøveforelesning
Bedømmelseskomitè
Dr. Gabi Schierning, Institute for Metallic Materials Leibniz- Institute for Solid State and Materials Research (IFW), Tyskland
Professor Ulrik Hanke, Høgskolen i Sørøst-Norge, Norge
Professor Vidar Hansen, Universitetet i Oslo, Norge
Leder av disputas
Førsteamanuensis Helge Balk
Veiledere
Professor Terje Finstad
Professor Ole Martin Løvvik
Sammendrag
Termoelektriske enheter konverterer spillvarme til elektrisitet, eller omvendt, og kan dermed øke den totale energiproduksjonen og utnyttelseseffektiviteten. Dette doktorgradsarbeidet fokuserer på det termoelektriske materialet ZnSb, som har fordeler av å være billig, tilgjengelig og miljøvennlig, og samtidig yter best ved moderat temperatur, noe som er aktuelt for utnyttelse av spilevarme fra industri og transport. Materialegenskapene ble forbedret gjennom nanostrukturering, modifikasjon av den elektroniske strukturen og spredningsmekanismer. Eksperimentelle og teoretiske metoder ble kombinert for å få en dypere forståelse av termoelektriske fenomenet.
------------
Thermoelectric device converts waste heat into electricity, or vice versa, thereby enhancing the total energy output and exploitation efficiency. Although it always competes against other means of waste heat harvesting, its advantages, such as flexibility (scalability and compactness), human friendliness (no noise and toxicity) and no moving parts (less wear), allow it plays an important role in global energy management. In order to implement thermoelectric devices in a wide utilization, material improvement based on cheap and abundant elements is essential. This PhD work focuses on the thermoelectric material ZnSb, which has the aforesaid advantages meanwhile the optimal output at moderate temperature for many of industry and transportation waste.
This work was built upon an understanding of semiconductor transport. The methodological focus is on different synthesis techniques to produce nanostructured bulk material, microstructural characterization, as well as the investigation of thermoelectric transport properties. Doping was also introduced to modify the electronic structure and scattering mechanism. The property of the material was improved due to the reduced thermal conductivity by nanostructuring and the increased carrier concentrations by doping. Possible energy barrier at grain boundaries was verified. And many efforts have been made on the understanding of intrinsic defects and impurity band conduction, which led to a deeper knowledge of thermoelectrics.
For mer informasjon
Kontakt ekspedisjonskontoret:
E-post: ekspedisjon@fys.uio.no
Telefon: 22 85 64 28