Designing of Bulk Nano-Structures with Enhanced Thermoelectric Properties

We discovered a grand homologous series which may help in the future to systematically identify thermoelectric materials with high performance. Namely, the series AmM11Se212mM21nSe231n A alkali metal, M Pb, Bi has structure-predicting properties. The modular construction of these structures from evolving building blocks permits many of the criteria necessary for good thermoelectrics to be met. K2Bi8Se13 is a member of this series and was found to be a promising thermoelectric. The charge transport properties were studied under pressure, where a significant increase in the power factor was observed. Several other promising materials were also discovered. In another part of this project we prepared nanocrystals of thermoelectric semiconductors and studied their properties. We investigated the assembly of nanocrystal components into well-organized arrays. The goal was to utilize quantum dot building blocks of desired thermal and electronic properties to design composite materials with improved power generation, thermoelectric characteristics. We devised new ways to prepare nanocrystals of PbTe, AgSbTe2 and AgPb2SbTe4.