Correlation between microstructure and thermoelectric properties of AgPb18SbTe20 (LAST-18)

This study reports microstructure investigations at AgPb mSbTe2+m (m = 18) (Lead-Antimony-Silver-Tellurium, LAST-18). Two different length scales were explored. The micrometer scale was evaluated by SEM to analyze volume fraction and number of secondary phases as well as the impact of processing parameters on the homogeneity of bulk samples. Site-specific liftout of TEM lamellae from thermoelectrically characterised samples was made to investigate the structure on the nanometer scale. High-resolution TEM and energy-filtered TEM were performed to reveal shape and size distribution of nanoprecipitates, respectively. An attempt is made to derive a structure-property relationship.