Exploring Tantalum as a Potential Dopant to Promote the Thermoelectric Performance of Zinc Oxide.

Autor: Arias-Serrano BI; CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. blanca@ua.pt., Xie W; Materials and Resources, Techn, Universität Darmstadt, Alarich-Weiss Str.2, DE-64287 Darmstadt, Germany. wenjie.xie@imw.uni-stuttgart.de., Aguirre MH; Condensed Matter Physics Department, University of Zaragoza and Institute of Material Science of Aragón, ICMA-CSIC, E-50018 Zaragoza, Spain. maguirre@unizar.es.; Advanced Microscopy Laboratory, I+D Building-Campus Río Ebro, C/Mariano Esquillor s/n, 50018 Zaragoza, Spain. maguirre@unizar.es., Tobaldi DM; CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. david.tobaldi@ua.pt., Sarabando AR; CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. artursarabando@ua.pt., Rasekh S; CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. shahedvrm@ua.pt.; i3N, Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal. shahedvrm@ua.pt., Mikhalev SM; TEMA-NRD, Mechanical Engineering Department, Aveiro Institute of Nanotechnology (AIN), University of Aveiro, 3810-193 Aveiro, Portugal. akavaleuski@ua.pt., Frade JR; CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. jfrade@ua.pt., Weidenkaff A; Materials and Resources, Techn, Universität Darmstadt, Alarich-Weiss Str.2, DE-64287 Darmstadt, Germany. anke.weidenkaff@iwks.fraunhofer.de., Kovalevsky AV; CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. akavaleuski@ua.pt.
Jazyk: angličtina
Zdroj: Materials (Basel, Switzerland) [Materials (Basel)] 2019 Jun 26; Vol. 12 (13). Date of Electronic Publication: 2019 Jun 26.
DOI: 10.3390/ma12132057
Abstrakt: Zinc oxide (ZnO) has being recognised as a potentially interesting thermoelectric material, allowing flexible tuning of the electrical properties by donor doping. This work focuses on the assessment of tantalum doping effects on the relevant structural, microstructural, optical and thermoelectric properties of ZnO. Processing of the samples with a nominal composition Zn 1-x Ta x O by conventional solid-state route results in limited solubility of Ta in the wurtzite structure. Electronic doping is accompanied by the formation of other defects and dislocations as a compensation mechanism and simultaneous segregation of ZnTa 2 O 6 at the grain boundaries. Highly defective structure and partial blocking of the grain boundaries suppress the electrical transport, while the evolution of Seebeck coefficient and band gap suggest that the charge carrier concentration continuously increases from x = 0 to 0.008. Thermal conductivity is almost not affected by the tantalum content. The highest ZT ~0.07 at 1175 K observed for Zn 0.998 Ta 0.002 O is mainly provided by high Seebeck coefficient (-464 V/K) along with a moderate electrical conductivity of ~13 S/cm. The results suggest that tantalum may represent a suitable dopant for thermoelectric zinc oxide, but this requires the application of specific processing methods and compositional design to enhance the solubility of Ta in wurtzite lattice.
Competing Interests: The authors declare no conflicts of interest.
Databáze: MEDLINE
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