Synthesis and Thermoelectric Properties of Cu0.95Pt0.05Fe0.97Sn0.03O2 Delafossite-Oxide

Abstract

The Cu0.95Pt0.05Fe0.97Sn0.03O2 delafossite sample, which is the simultaneous substitution of the Pt for Cu sites and the Sn for Fe sites of CuFeO2 delafossite, has been investigated the simultaneous effect on electrical conductivity and Seebeck Coefficient for thermoelectric materials due to the previous reports of Cu0.95Pt0.05FeO2 compound displaying high enhancement effect of electric conductivity and the CuFe0.97Sn0.03O2 exhibiting large increasing of Seebeck coefficient. The sample of Cu0.95Pt0.05Fe0.97Sn0.03O2 was synthesized by solid state reaction method. The crystal structure was characterized by XRD, and the valency oxidation state of the sample was evaluated by XPS. The electrical conductivity, Seebeck coefficient, and thermoelectric conductivity were measured in the high temperature range of 320 to 860 K. The measurement results show that, the sign of Seebeck value and result of XPS reveal the sample displaying p-type thermoelectric materials as confirming the simultaneous Pt and Sn-substituted contributing hole carrier. For the effect of simultaneous substitution, the Seebeck coefficient is enhanced in temperature lower than 650 K, while electrical conductivity displays small value in all temperature range. In surprising value, the thermal conductivity of the sample is smallest value in all temperature range. Totally, the ZT value of sample is obtained 0.07 at 860K as higher than that of the reference-based. This experiment confirms that the simultaneous Pt-doped and Sn-doped of Cu0.95Pt0.05Fe0.97Sn0.03O2 compound show high ZT value in temperature higher than 700 K.