16:30 〜 16:45
▲ [15p-A35-12] Synthesis and thermoelectric properties of quaternary Si clathrate K8-δGaxZnySi46-x-y
キーワード：Clathrate silicides, Thermoelectric, Intermetallic
Group 14 clathrates have received significant attention as functional materials such as thermoelectric and photovoltaic materials [1-4]. In this study, we synthesized quaternary Si clathrate K8GaxZnySi46-x-y and investigated their thermoelectric properties. By systematically substituting trivalent Ga atom with divalent Zn atom, we change the average valence of GaxZny in the clathrate cage framework and see its effects on the thermoelectric properties. X-ray diffraction patterns confirm synthesis of clathrate although it contain a trace of secondary phase Si. Spark plasma sintering was carried out to obtain compact specimens for compositional and physical property characterizations. Electron probe micro-analysis confirmed formation of ternary and quaternary phase clathrate. K7.7Zn3.2Si43.0 and K7.6Ga5.8Zn0.8Si39.6 show metallic conduction and the other samples depict semiconducting conduction. The Seebeck coefficient of all the samples is negative, indicating that dominant carriers are electrons. Maximum ZT obtained for sample K7.6Ga5.8Zn0.8Si39.6 was 0.01 at 320 K.
References:
[1] The Physics and Chemistry of Inorganic Clathrates, Ed. G.S.Nolas (Springer, Heidelberg, 2014)
[2] T. Takabatake et al., Rev. Mod. Phys. 86, (2014) 669.
[3] S. K. Singh et al. Jpn. J. Appl. Phys. 54 (2015) 091801.
[4] Y. He et al. Energy Environ. Sci. 7 (2014) 2598.
References:
[1] The Physics and Chemistry of Inorganic Clathrates, Ed. G.S.Nolas (Springer, Heidelberg, 2014)
[2] T. Takabatake et al., Rev. Mod. Phys. 86, (2014) 669.
[3] S. K. Singh et al. Jpn. J. Appl. Phys. 54 (2015) 091801.
[4] Y. He et al. Energy Environ. Sci. 7 (2014) 2598.