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 ZrCo 1 - x Ir x Sb (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 ( Ir x ) from x = 0 to 0.375 in the ZrCo 1 - x Ir x Sb alloys from room temperature to 800 K significantly decreased thermal and electrical conductivity due to a shorter relaxation time. Furthermore, our results show that ZrCo 0.625 Ir 0.375 Sb has the highest Seebeck coefficient (353.93 μ 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 ⋅ 10 20 cm - 3 at 1000 K and 37.5% (x = 0.375) of atomic doping of iridium (Ir) with a carrier concentration of n = 7.23 ⋅ 10 19 cm - 3 at 800 K . Calculations present important results on the suitability of the studied alloys for thermoelectric applications.