[9a-PA1-1~13] 9.4 Thermoelectric conversion

▲ [9a-PA1-12] Electronic structure modification of BaSb_xSn_1-xO₃ materials thermoelectric application

〇(D)Rajasekaran Palani¹, Yuki Kumaki¹, Arivanandhan Mukannan², Jayavel Ramasamy², Masaru Shimomura¹ (1.Shizuoka University, 2.Anna University)

Keywords:Thermoelectric, Band Structure

Thermoelectric technique is alternate approach of utilizing waste thermal energy and converts into electrical energy at low cost. In this research BaSb_xSn_1-xO₃ perovskite materials were prepared by polymerization complex method. XRD pattern analysis of the samples show the cubic structure. Morphological images measured by SEM and TEM show the microstructure of the interconnected cubic particles. The band structures of the BaSb_xSn_1-xO₃ were calculated using 3×3×3 super cell. In the calculated BaSnO₃ band structure, valance band maximum is located below the Fermi level. After substitution of Sb atom into the Sn site, Fermi energy level is shifted towards the Sn-5s band. From the XPS analysis, Sb⁵⁺ ions only exist and no Sb³⁺ ions were detected. Hall electrical conductivity measurement showed donor type semiconducting property. Seebeck coefficient was -60 μV/K for the BaSb_0.010Sn_0.990O₃ sample and the resistivity was low at the higher temperature. The power factor of 2.1 μW/mK² was measured BaSb_0.010Sn_0.990O₃ sample. The room temperature thermal conductivity showed 1.05 W/mK in both samples. In higher temperature, thermal conductivity was reduced and BaSb_0.005Sn_0.995O₃ for 0.595 W/mK and BaSb_0.010Sn_0.990O₃ for 0.631 W/mK were measured. The thermoelectric figure of merit ZT-0.028 was achieved with the BaSb_0.010Sn_0.990O₃ sample at 819 K.