BiCuSeO/GdH2 thermoelectric composite: a p-type to n-type promoter with superior charge transport

Abstract

We herein report on compositing highly conductive GdH2 with BiCuSeO, with an aim to modulate the electronic transport and the nature of conductivity in the high-temperature regime. The incorporation of GdH2 as a minor matrix in BiCuSeO, as confirmed by structural studies, has considerably enhanced electrical conductivity in the system, thereby demonstrating the existence of thermal activation of the charge carriers. The effect of minor matrix is directly on the conversion of p-type to n-type conductivity in BiCuSeO system at near room temperature. Electronic quality factor (BE) has identified the ambiguities in the transport behaviour at near room temperature due to the addition of minor matrix. Enhancement in the power factor is seen due to GdH2, with a highest attained value of 221 μW m K−2 at 700 K for the sample with x = 11 wt%, which is nearly twice the value of pristine BiCuSeO. Highest ZT of 0.011 is obtained for the pristine BiCuSeO sample at 380 K.