Duck Young Chung

Electrical Properties and Figures of Merit for New Chalcogenide-Based Thermoelectric Materials

New Bi-based chalcogenide compounds have been prepared using the polychalcogenide flux technique for crystal growth. These materials exhibit characteristics of good thermoelectric materials. Single crystals of the compound CsBi{sub 4}Te{sub 6} have shown conductivity as high as 2440 S/cm with a p-type thermoelectric power of {approx}+110 {micro}V/K at room temperature. A second compound, {beta}-K{sub 2}Bi{sub 8}Se{sub 13} shows lower conductivity {approx}240 S/cm, but a larger n-type thermopower {approx}{minus}200 {micro}V/K. Thermal transport measurements have been performed on hot-pressed pellets of these materials and the results show comparable or lower thermal conductivities than Bi{sub 2}Te{sub 3}. This improvement may reflect the reduced lattice symmetry of the new chalcogenide thermoelectrics. The thermoelectric figure of merit for CsBi{sub 4}Te{sub 6} reaches ZT {approx} 0.32 at 260 K and for {beta}-K{sub 2}Bi{sub 8}Se{sub 13} ZT {approx} 0.32 at room temperature, indicating that these compounds are viable candidates for thermoelectric refrigeration applications.

Transport properties of doped CsBi4Te6 thermoelectric materials

In previous investigations we have introduced a variety of new chalcogenide-based materials with promising properties for thermoelectric applications. The chalcogenide CsBi 4 Te 6 was previously reported to have a high ZT product with a maximum value at 260K. In order to improve this value, a series of doped CsBi 4 Te 6 samples has been synthesized. Current doping studies have been very encouraging, with one sample found to have a maximum power factor of 51.5 μW/cm·K 2 at 184 K. This paper reports on material characterization studies through the usual transport measurements to determine optimum doping concentration for various dopants.

CCDC 1576250: Experimental Crystal Structure Determination

Related Article: Daniel E. Bugaris, Christos D. Malliakas, Sergey L. Bud’ko, Nicholas P. Calta, Duck Young Chung, Mercouri G. Kanatzidis|2017|Inorg.Chem.|||doi:10.1021/acs.inorgchem.7b02389