abstract
Zinc oxide (ZnO) has a very broad and versatile range of applications provided by its high abundance and optical and electrical properties, which can be further tuned by donor substitution. Al-doped ZnO is probably the most thoroughly investigated material with regard to thermoelectric properties. Fairly reasonable electrical properties of donor-doped zinc oxide are usually combined with high thermal conductivity limiting potential applications. Here we report a new self-forming nanocomposite concept for ZnO-based thermoelectrics, where a controllable interplay between the exsolution of the nanophases and modification of the host matrix suppresses the thermal transport while imparting enhanced electrical performance. The thermoelectric performance of the best-obtained composite, described by the dimensionless figure-of-merit ZT, at 920-1200 K is almost twice that of the pure matrix composition and reaches up to 0.11. The proposed approach invokes controlled interactions between composite components as a novel tool for decoupling the electrical and thermal transport parameters and shows clear prospects for an implementation in other thermoelectric oxide systems. The results indicate that the proposed concept may also constitute a promising pathway to achieve stable electrical performance at high temperatures, which currently represents one of the major challenges towards achieving ZnO-based thermoelectrics.
keywords
AL-DOPED ZNO; LATTICE THERMAL-CONDUCTIVITY; POWER-FACTOR; ZINC-OXIDE; ELECTRICAL-CONDUCTIVITY; MONOCLINIC ZIRCONIA; STABILIZED ZIRCONIA; DEFECT CHEMISTRY; TEMPERATURE; PERFORMANCE
subject category
Chemistry; Energy & Fuels; Materials Science
authors
Zakharchuk, KV; Widenmeyer, M; Alikin, DO; Xie, WJ; Populoh, S; Mikhalev, SM; Tselev, A; Frade, JR; Weidenkaff, A; Kovalevsky, AV
our authors
Alexander Tselev
Principal Researcher
Andrei Kavaleuski
Principal Researcher
Denis Alikin
Assistant Researcher
Jorge Ribeiro Frade
Retired Professor
Kiryl Zakharchuk
PhD Student
Sergey Mikhalev
Post-Doc FellowshipGroups
G2 - Photonic, Electronic and Magnetic Materials
G3 - Electrochemical Materials, Interfaces and Coatings
acknowledgements
This work was supported by the FCT, including the individual grant IF/00302/2012, project CICECO-Aveiro Institute of Materials (ref. UID/CTM/50011/2013), project of bilateral cooperation between FCT and DAAD (Germany) and projects POCI-01-0145-FEDER-031875 and POCI-01-0145-FEDER-032117, financed by the COMPETE 2020 Program and National Funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. The authors are thankful to Artur Sarabando (University of Aveiro) and to Dr P. Thiel (Empa) for their technical and experimental support.