In Situ Nanostructure Generation and Evolution within a Bulk Thermoelectric Material to Reduce Lattice Thermal Conductivity

Abstract

We show experimentally the direct reduction in lattice thermal conductivity as a result of in situ nanostructure generation within a thermoelectric material. Solid solution alloys of the high-performance thermoelectric PbTe-PbS 8% can be synthesized through rapid cooling and subsequent high-temperature activation that induces a spontaneous nucleation and growth of PbS nanocrystals. The emergence of coherent PbS nanostructures reduces the lattice thermal conductivity from approximately 1 to approximately 0.4 W/mK between 400 and 500 K.

Heterostructured Approaches to Efficient Thermoelectric Materials

“…After annealing, this composite with two semiconducting phases (PbS and PbTe) exhibits a comparable extent of reduction in thermal conductivity as that in ref. 44, and thereby has a high zT of over 1.0 at ~ 700 K, which is slightly lower (~ 20%) than the zT record for the same compositions, but made by solid--state syntheses. This result shows considerable promise for the use of solution syntheses to generate high zT values, and thus avoid high temperature processes.…”

Enhanced Thermoelectric Performance in PbTe–PbS Nanocomposites

“…In the PbTe-PbS-400 sample, no spinodal structure was found. The nanoparticles formed by nucleation and growth have been reported to be effective in scattering phonons (Androulakis et al 2007;Girard et al 2010). The interface area between the precipitated phase and matrix has been expected to be larger with higher compositional contrast.…”

Electron Microscopy for Characterization of Thermoelectric Nanomaterials

“…The biggest advances in this field have been achieved in nanostructured PbTe-based materials in which very low k can be obtained, resulting in the highest ZT values among all TEs. To date, both n-type (e.g., AgPb m SbTe m+2 (LAST) [28,30], Pb 1-x Sn x Te-PbS [31], PbTe-CdTe [32], PbTe-PbS [33], PbTe-Ge/GeSi/Si [34,35], and PbTe-Ag 2 Te [36]) and p-type (e.g., AgPb m Sn n SbTe m+n+2 (LASTT) [29,37], PbTe 1-x Se x [38], NaPb m SbTe m+2 (SALT) [39], PbTe-XTe (X ¼ Mg [40], Ca [41], Sr [42,43], Ba [41,44]), PbTe-PbS [45][46][47], and PbTe-PbSnS 2 [48,49]) materials have been developed. These materials above, the leading commercialized TE materials as well as those poised for commercialization in the near future, however, all contain a significant amount of Te or Ge, which is scarce in the earth's crust.…”

“…Detailed sample preparation of doped PbTe [83,84], PbTe + XTe (X ¼ Mg, Ca, Sr, Ba, Cd) [32,[40][41][42][43][44], PbTe + PbS [33,[45][46][47], PbTe + PbSnS 2 [48,49], PbTe + X (X ¼ Pb, Sb, Bi, Si/Ge) [34,35,85,86], TAGS [87], LAST(T) [88], SALT [89,90], and PbTe-Sb 2 Te 3 [91] can be found in corresponding literatures, which will be discussed in the following sections.…”