Thermoelectric performance of SnTe with ZnO carrier compensation, energy filtering, and multiscale phonon scattering

Abstract

In this work, the thermoelectric properties of SnTe have been regulated synergistically by introduction of n‐type ZnO nanoinclusions. On one hand, the excessive holes in SnTe matrix were compensated properly by n‐type ZnO, and the Seebeck coefficient has been improved greatly due to the carrier energy filtering effect by a large quantity of ZnO‐SnTe hetero‐junction interface barriers; On the other hand, the thermal conductivity gets reduced by the enhanced phonon scattering from multiscale hierarchical architectures. Consequently, a maximum ZT of ~0.9 at 873K has been obtained in the 0.8 wt% sample, which enhances by 112% in comparison with the nanoinclusion‐free sample.

Energy Filtering of Charge Carriers: Current Trends, Challenges, and Prospects for Thermoelectric Materials

“…In general, SnTe‐based p‐type chalcogenides are known for their high hole density (≈10 20 –10 21 cm −3 ); therefore, EF is made possible in this system. Zhou et al incorporated ZnO particles in a SnTe matrix and observed surprising results . The wide bandgap ZnO phase forming a hole‐blocking layer in the SnTe matrix increases the Seebeck coefficient.…”

“…This forms a potential well that traps charge carriers. Thus, S was found to increase with increasing temperature due to the mixed effects of the charge carrier EF and charge compensation . Liu et al have recently modified the concept of electron MFP in p‐type SnTe: nanostructures with typical dimensions less than 10 nm can filter‐out easily the long‐MFP electrons.…”

“…d) A HRTEM image of the interface between SnTe and ZnO showing the lattice mismatch. Adapted with permission . Copyright 2017, The American Ceramic Society.…”

Inorganic thermoelectric materials: A review

“…Best performing oxide‐based materials highlighting (A) highest σ, (B) low κ t and (C) ZT value via miscellaneous optimization techniques …”

Boosted carrier mobility and enhanced thermoelectric properties of polycrystalline Na0.03Sn0.97Se by liquid-phase hot deformation

“…The excellent TE performance could be realized by increasing the power factor (PF = a 2 s) or compressing the thermal conductivity as much as possible. [6][7][8] Usually, several strategies such as resonant doping, 9,10 band convergence [11][12][13] and carrier concentration optimization 14,15 can effectively increase the power factor, while the lattice thermal conductivity k l can be reduced by the all-scale hierarchical structuring [16][17][18][19] and dense defects [20][21][22][23] as phonon scattering centers.…”