| 학회 | 한국재료학회 |
| 학술대회 | 2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 | 22권 2호 |
| 발표분야 | H. 한-일 재료공학 워크샵 |
| 제목 | Transport property of layered oxychalcogenide for thermoelectric material |
| 초록 | The thermoelectric energy conversion technology, which can be used to convert wasted heat into electricity and to supply power for devices, has received much attention for several decades.[1] The efficiency of thermoelectric materials is characterized by the dimensionless figure of merit, ZT = (S2/ρκ)T, where S, ρ, κ, and T are Seebeck coefficient, electric resistivity, thermal conductivity, and the absolute temperature, respectively. Ideally, both of κ and S should be larger, while thermal conductivity should be smaller. (S, ρ, κ) are not independent variable, hence it is hard to find maximum values of ZT for a material. Recently, several classes of bulk materials with high ZT values have been discovered. Now, we have researched on a layered oxychalcogenide, which shows very low thermal conductivity and moderate Seebeck coefficient and electric conductivity. The main feature of the oxychalcogenide can be summarized as: the crystal structure constituted by (Cu2Ch2)2- layers alternately stacked with (Ln2O2)2+ layers along the c axis of thetetragonal cell. Figure 1 shows crystallographic structure of the oxychalcogenide with space group P4/mmn. One of the oxychalcogenide, BiCuSeO have been reported as a new material demonstrating a high ZT value of ~1.1 at 923 K with Ba doped.[2] In this study, polycrystalline samples with chemical compositions LaCuSO, LaCuSeO, CeCuSO and BiCuSeO were synthesized by solid state reaction. Transport property of samples, ρ by four terminal method and κ and S by steady state method, were measured at T ＞ 300 K. Both of BiCuSeO and LaCuSeO show similar ρ~0.68 Ωcm at 773 K. Absolute values of S for BiCuSeO are ~405 μV/K while LaCuSeO show far lower S at 373 K. The smallest κ of them are observed for CeCuSO at T = 300-700 K. REFERENCES [1] Y. Goto, Ph. D. thesis “Electrical/Thermal Transport Properties and Electronic Structure of Stannite-type and Mixed-anion-type Copper Sulfides”, Keio Univ., Japan (2015). in Japanese [2] Jing Li, et al., Energy Environ. Sci., 5, 8543 (2012). |
| 저자 | Satoru KATSUMATA1, Hiroki KINOSHITA2, Masanori MATOBA1, Yoichi KAMIHARA2 |
| 소속 | 1Keio Univ., 2Japan |
| 키워드 | thermoelectric material; oxychalcogenide; layered structure; thermal conductivity |
