title: A new thermoelectric material: CsBi4Te6.
abstract: The highly anisotropic material CsBi(4)Te(6) was prepared by the reaction of Cs/Bi(2)Te(3) around 600 degrees C. The compound crystallizes in the monoclinic space group C2/m with a = 51.9205(8) A, b = 4.4025(1) A, c = 14.5118(3) A, beta = 101.480(1) degrees, V = 3250.75(11) A(3), and Z = 8. The final R values are R(1) = 0.0585 and wR(2) = 0.1127 for all data. The compound has a 2-D structure composed of NaCl-type [Bi(4)Te(6)] anionic layers and Cs(+) ions residing between the layers. The [Bi(4)Te(6)] layers are interconnected by Bi-Bi bonds at a distance of 3.2383(10) A. This material is a narrow gap semiconductor. Optimization studies on the thermoelectric properties with a variety of doping agents show that the electrical properties of CsBi(4)Te(6) can be tuned to yield an optimized thermoelectric material which is promising for low-temperature applications. SbI(3) doping resulted in p-type behavior and a maximum power factor of 51.5 microW/cm.K(2) at 184 K and the corresponding ZT of 0.82 at 225 K. The highest power factor of 59.8 microW/cm.K(2) at 151 K was obtained from 0.06% Sb-doped material. We report here the synthesis, physicochemical properties, doping characteristics, charge-transport properties, and thermal conductivity. Also presented are studies on n-type CsBi(4)Te(6) and comparisons to those of p-type.
authors.affiliation: Department of Chemistry and Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Duck-Young
authors.initials: DY
authors.lastname: Chung
authors.forename: Tim P
authors.initials: TP
authors.lastname: Hogan
authors.forename: Melissa
authors.initials: M
authors.lastname: Rocci-Lane
authors.forename: Paul
authors.initials: P
authors.lastname: Brazis
authors.forename: John R
authors.initials: JR
authors.lastname: Ireland
authors.forename: Carl R
authors.initials: CR
authors.lastname: Kannewurf
authors.forename: Marina
authors.initials: M
authors.lastname: Bastea
authors.forename: Ctirad
authors.initials: C
authors.lastname: Uher
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis