Realizing p-type NbCoSn half-Heusler compounds with enhanced thermoelectric performance via Sc substitution

N-type half-Heusler NbCoSn is a promising thermoelectric material due to favourable electronic properties. It has attracted much attention for thermoelectric applications while the desired p-type NbCoSn counterpart shows poor thermoelectric performance. In this work, p-type NbCoSn has been obtained using Sc substitution at the Nb site, and their thermoelectric properties were investigated. Of all samples, Nb_0.95Sc_0.05CoSn compound shows a maximum power factor of 0.54 mW/mK² which is the highest among the previously reported values of p-type NbCoSn. With the suppression of thermal conductivity, p-type Nb_0.95Sc_0.05CoSn compound shows the highest measured figure of merit ZT = 0.13 at 879 K.