The global energy crisis demands the search for new materials for efficient thermoelectric energy conversion. Theoretical predictive modelling with experiments can expedite the global search of novel and ecoconscious thermoelectric...

The effect of alloying on the thermoelectric properties of cobaltite, CoAsS, and paracostibite, CoSbS, has been investigated in this study. Density functional theory and the Boltzmann transport equation have been applied to explore the role of phonon-phonon scattering and atomistic scattering due to alloying in phonon transport. An almost 44% reduction in thermal conductivity of CoAsSbS alloy compared to pure CoAsS and an ∼15% reduction in thermal conductivity of CoAsSbS compared to pure CoSbS were found. Simultaneously, the thermoelectric (TE) figure of merit (ZT) increased by ∼11% in p-type CoAsSbS alloy and ∼8% in n-type CoAsSbS alloy as compared to their base pure materials at 800 K. We found that by tuning the composition of CoAsSbS alloy, very similar ZT values for both p-type and n-type can be achieved in a large temperature range. We also calculated the TE properties of CoAsSeS and CoSbSSe alloys. This study will help in designing CoAsSbS based alloys for efficient thermoelectric devices.

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