Carrier grain boundary scattering in thermoelectric materials

Abstract

Bulk nanostructuring has been one of the leading strategies employed in the past decade for the optimization of thermoelectric properties by introducing strong grain boundary scattering of low-frequency phonons. However,...

A robust thermoelectric module based on MgAgSb/Mg3(Sb,Bi)2with a conversion efficiency of 8.5% and a maximum cooling of 72 K

“…, ρ ∼ T −1.95 , whereas the sample sintered at 1023 K and 1073 K displays the relationships of ρ ∼ T −0.1 and ρ ∼ T 0.5 , respectively, suggesting the concerting of the grain boundaries with acoustic phonons for scattering charge carriers. 46,47…”

Dramatic Enhancement of Thermoelectric Performance in PbTe by Unconventional Grain Shrinking in the Sintering Process

“…In addition, ionized impurities scattering is also excluded in materials with high dielectric constants, such as PbTe. [ 31 ] The role of dislocation scattering in Pb 0.98 Sb 0.02 Te sample is confirmed by simulation of σ using the equation below: [ 32 ] $$\[{\mu _{{\rm{disl}}}} = \frac{{30\sqrt {2\pi } {\varepsilon ^2}d_{{\rm{db}}}^2{{(kT)}^{3/2}}}}{{{N_{\rm{D}}}{e^3}{f^2}{\lambda _{\rm{d}}}\sqrt {{m^*}} }} \approx \frac{{{T^{3/2}}}}{{\sqrt {{m^*}} }}\]$$…”

“…In addition, the improved S in this work may be caused by the high E b value in Pb 0.98 Sb 0.02 Te originates from the hierarchical GBs. We infer that some trapping states may be enriched at the GBs of the nanoscale slender grains, [ 31 ] leading to an increased E b at the boundaries, which selectively scatters electrons to increase S (Figure 5e) in the 2nd‐sintered Pb 0.98 Sb 0.02 Te sample. [ 33 ]…”

“…In addition, ionized impurities scattering is also excluded in materials with high dielectric constants, such as PbTe. [31] The role of dislocation scattering in Pb 0.98 Sb 0.02 Te sample is confirmed by simulation of σ using the equation below: [32] where ε, d db , e, f, and λ d are the dielectric constant, the distance between acceptor centers along dislocation lines, the electron charge, the occupation rate of the acceptor centers, and the length of Debye screening. The calculated σ for Pb 0.98 Sb 0.02 Te match well with the experimental data (Figure 5a), which indicates that dislocation scattering does play a key role in carrier transport.…”

“…In addition, the improved S in this work may be caused by the high E b value in Pb 0.98 Sb 0.02 Te originates from the hierarchical GBs. We infer that some trapping states may be enriched at the GBs of the nanoscale slender grains, [31] leading to an increased E b at the boundaries, which selectively scatters electrons to increase S (Figure 5e) in the 2nd-sintered Pb 0.98 Sb 0.02 Te sample. [33] The T-dependent total thermal conductivity (k tot ) and lattice thermal conductivity (k lat ) of Pb 1−x Sb x Te (x = 0-0.04) samples are shown in Figure 6a and Figure S13, Supporting Information.…”