Impact of Ir doping on the thermoelectric transport properties of half-Heusler alloys

Using density functional and and Boltzmann transport theories, we investigate the thermoelectric transport properties ZrCo1-xIrxSb (x = 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, 1) half-Heusler alloys. The current work found that increasing the concentration of iridium ( Irx ) from x = 0 to 0.375 in the ZrCo1-xIrxSb alloys from room temperature to 800 K significantly decreased thermal and electrical conductivity due to a shorter relaxation time. Furthermore, our results show that ZrCo0.625Ir0.375Sb has the highest Seebeck coefficient (353.93 mu V/K ) at 300 K, thereby boosting its thermoelectric performance. Interestingly, the thermoelectric figure of merit (ZT) has exceptional value 1.01 by applying 25% (x = 0.25) of atomic doping of iridium (Ir) with a carrier concentration of n=1.47 & sdot;1020cm-3 at 1000 K and 37.5% (x = 0.375) of atomic doping of iridium (Ir) with a carrier concentration of n=7.23 & sdot;1019cm-3 at 800 K. Calculations present important results on the suitability of the studied alloys for thermoelectric applications.