Synergistic effects of zirconium- and aluminum co-doping on the thermoelectric performance of zinc oxide

• Autor(a) principal: Zakharchuk, Kiryl V.
• Data de Publicação: 2019
• Outros Autores: Tobaldi, David M., Xiao, Xingxing, Xie, Wenjie, Mikhalev, Sergey M., Martins, João F., Frade, Jorge R., Weidenkaff, Anke, Kovalevsky, Andrei V.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/26338
• topic: Electrical properties; Thermal conductivity; Thermoelectric performance; Zinc oxide; Zirconium doping

This work aims to explore zirconium as a possible dopant to promote thermoelectric performance in bulk ZnO-based materials, both within the single-doping concept and on simultaneous co-doping with aluminum. At 1100–1223 K mixed-doped samples demonstrated around ∼2.3 times increase in ZT as compared to single-doped materials, reaching ∼0.12. The simultaneous presence of aluminum and zirconium imposes a synergistic effect on electrical properties provided by their mutual effects on the solubility in ZnO crystal lattice, while also allowing a moderate decrease of the thermal conductivity due to phonon scattering effects. At 1173 K the power factor of mixed-doped Zn0.994Al0.003Zr0.003O was 2.2–2.5 times higher than for single-doped materials. Stability tests of the prepared materials under prospective operation conditions indicated that the gradual increase in both resistivity and Seebeck coefficient in mixed-doped compositions with time may partially compensate each other to maintain a relatively high power factor