Abstract
Two new layered compounds Rb2ZnBi2Se5 and Cs6Cd2Bi8Te17 are described. Rb2ZnBi2Se5 crystallizes in the orthorhombic space group Pnma, with lattice parameters of a = 15.6509(17) Å, b = 4.218(8) Å, and c = 18.653(3) Å. Cs6Cd2Bi8Te17 crystallizes in the monoclinic C2/m space group, with a = 28.646(6) Å, b = 4.4634(9) Å, c = 21.164(4) Å, and β = 107.65(3)°. The two structures are different and composed of anionic layers which are formed by inter connecting of BiQ6 octahedra (Q = Se or Te) and MQ4 (M = Zn or Cd) tetrahedra. The space between the layers hosts alkali metal as counter cations. The rubidium atoms of Rb2ZnBi2Se5 structure can be exchanged with other cations (Cd2+, Pb2+ and Zn2+) in aqueous solutions forming new phases. Rb2ZnBi2Se5 is an n-type semiconductor and exhibits an indirect band gap energy of 1.0 eV. Rb2ZnBi2Se5 is a congruently melting compound (mp ∼644 °C). The thermal conductivity of this semiconductor is very low with 0.38 W·m-1·K-1 at 873 K. Density functional theory (DFT) calculations suggest that the low lattice thermal conductivity of Rb2ZnBi2Se5 is attributed to heavy Bi atom induced slow phonon velocities and large Gruneisen parameters especially in the a and c directions. The thermoelectric properties of Rb2ZnBi2Se5 were characterized with the highest ZT value of ∼0.25 at 839 K.
Original language | English (US) |
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Pages (from-to) | 9403-9411 |
Number of pages | 9 |
Journal | Inorganic chemistry |
Volume | 57 |
Issue number | 15 |
DOIs | |
State | Published - Aug 6 2018 |
Funding
This work was supported in part by Beijing Natural Science Foundation, China (2182080, 2182029) and a Grant from the National Science Foundation of China (51702329). At Northwestern this work was supported by the National Science Foundation (Grant DMR-1708254, exploratory synthesis and characterization). This work made use of the EPIC facility (NUANCE Center-Northwestern University) which has received support under the State of Illinois, Northwestern University, and the National Science Foundation with Grants DMR-1121262 through the MRSEC program at the Materials Research Center, and EEC-0118025/003 through The Nanoscale Science and Engineering Center. S. H. and C.W. (DFT calculations) acknowledge support from the Department of Energy Office of Science Basic Energy Sciences under Grant DE-SC0014520. Access of QUEST, the supercomputer resources facilities at Northwestern University, is acknowledged. This work was supported in part by Beijing Natural Science Foundation, China (2182080, 2182029) and a Grant from the National Science Foundation of China (51702329). At Northwestern this work was supported by the National Science Foundation (Grant DMR-1708254, exploratory synthesis and characterization). This work made use of the EPIC facility (NUANCE Center-Northwestern University), which has received support under the State of Illinois, Northwestern University, and the National Science Foundation with Grants DMR-1121262 through the MRSEC program at the Materials Research Center, and EEC-0118025/003 through The Nano-scale Science and Engineering Center. S. H. and C.W. (DFT calculations) acknowledge support from the Department of Energy, Office of Science Basic Energy Sciences under Grant DE-SC0014520. Access of QUEST, the supercomputer resources facilities at Northwestern University, is acknowledged.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
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CSD 1845892: Experimental Crystal Structure Determination
Zhao, J. (Creator), Hao, S. (Creator), Islam, S. M. (Creator), Chen, H. (Creator), Ma, S. (Creator), Wolverton, C. (Creator) & Kanatzidis, M. G. (Creator), FIZ Karlsruhe – Leibniz Institute for Information Infrastructure, 2018
DOI: 10.25505/fiz.icsd.cc1zysxm, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc1zysxm&sid=DataCite
Dataset
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CSD 1845971: Experimental Crystal Structure Determination
Zhao, J. (Contributor), Hao, S. (Contributor), Islam, S. M. (Contributor), Chen, H. (Contributor), Ma, S. (Contributor), Wolverton, C. (Contributor) & Kanatzidis, M. G. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2018
DOI: 10.25505/fiz.icsd.cc1zywg8, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc1zywg8&sid=DataCite
Dataset