Substantial thermoelectric enhancement achieved by manipulating the band structure and dislocations in Ag and La co-doped SnTe
SnTe, band convergence, dislocation, Ag and La co-doping, thermoelectric performance
Eco-friendly SnTe based thermoelectric materials are intensively studied recently as candidates to replace PbTe; yet the thermoelectric performance of SnTe is suppressed by its intrinsically high carrier concentration and high thermal conductivity. In this work, we confirm that the Ag and La co-doping can be applied to simultaneously enhance the power factor and reduce the thermal conductivity, contributing to a final promotion of figure of merit. On one hand, the carrier concentration and band offset between valence bands are concurrently reduced, promoting the power factor to a highest value of ~2436 μW·m-1·K-2 at 873 K. On the other hand, lots of dislocations (~3.16×107 mm-2) associated with impurity precipitates are generated, resulting in the decline of thermal conductivity to a minimum value of 1.87 W·m-1·K-1 at 873 K. As a result, a substantial thermoelectric performance enhancement up to zT ≈ 1.0 at 873 K is obtained for the sample Sn0.94Ag0.09La0.05Te, which is twice that of the pristine SnTe (zT ≈ 0.49 at 873 K). This strategy of synergistic manipulation of electronic band and microstructures via introducing rare earth elements could be applied to other systems to improve thermoelectric performance.
XU, Wenjing; ZHANG, Zhongwei; LIU, Chengyan; GAO, Jie; YE, Zhenyuan; CHEN, Chunguang; PENG, Ying; BAI, Xiaobo; and MIAO, Lei
"Substantial thermoelectric enhancement achieved by manipulating the band structure and dislocations in Ag and La co-doped SnTe,"
Journal of Advanced Ceramics: Vol. 10
, Article 14.
Available at: https://dc.tsinghuajournals.com/journal-of-advanced-ceramics/vol10/iss4/14