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  • 02월 19일 10시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제121회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Complex Zintl Phase Ca9Zn4.47(1)Sb9 and Ca8.15(2)Yb0.85Zn4.46(1)Sb9 for the Thermoelectric Material Application

2018년 2월 7일 16시 38분 47초
INOR.P-187 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
4월 19일 (목요일) 11:00~12:30
Inorganic Chemistry
저자 및
Ki Won Kim, Tae-Soo You*
Department of Chemistry, Chungbuk Natioanl University, Korea

Thermoelectric (TE) materials can be used to transfer the wasted heat from many different heat sources into electricity via the Seebeck effect. Among various candidate materials, Zintl phase compounds are one of the most attractive choices for TE application due to their intrinsically complex crystal structures and semiconducting characteristics. Two title Zintl compounds Ca9Zn4.47(1)Sb9 and Ca8.15(2)Yb0.85Zn4.46(1)Sb9 have been synthesized by using the high temperature reaction and characterized by PXRD and SXRD. Both compounds crystallized in the orthorhombic Ca9Mn4Bi9-type structure (space group Pbam, Pearson code oP48). According to our SXRD refinement results, the unit cells of two isotypic title compounds include total 13 crystallographically independent atomic sites including five cationic sites, five Sb sites, and three Zn sites. In particular, one of the Zn site (Wyckoff 4g), which acts as a bridge connecting the chains of dimerized tetrahedral ∞[Zn4Sb9] moieties, shows some vacancies. Since it is known that the partial occupation of this bridging Zn significantly affects the zT value, we attempted to fine tune the Zn amount to adjust the hole carrier concentration and introduce the mixed cations of Ca2+/Yb2+ to increase disordering in this system. A series of theoretical calculations using TB-LMTO method were also performed using several different structural models with different chemical compositions to understand the correlation between the given composition and the electronic structure. Detailed electronic energy of each model is further investigated, and DOS, COHP and ELF were also interrogated.