title: Non-equilibrium processing leads to record high thermoelectric figure of merit in PbTe-SrTe.
abstract: The broad-based implementation of thermoelectric materials in converting heat to electricity hinges on the achievement of high conversion efficiency. Here we demonstrate a thermoelectric figure of merit ZT of 2.5 at 923 K by the cumulative integration of several performance-enhancing concepts in a single material system. Using non-equilibrium processing we show that hole-doped samples of PbTe can be heavily alloyed with SrTe well beyond its thermodynamic solubility limit of <1 mol%. The much higher levels of Sr alloyed into the PbTe matrix widen the bandgap and create convergence of the two valence bands of PbTe, greatly boosting the power factors with maximal values over 30 μW cm(-1) K(-2). Exceeding the 5 mol% solubility limit leads to endotaxial SrTe nanostructures which produce extremely low lattice thermal conductivity of 0.5 W m(-1) K(-1) but preserve high hole mobilities because of the matrix/precipitate valence band alignment. The best composition is hole-doped PbTe-8%SrTe.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Gangjian
authors.identifier: 0000-0002-9087-4048
authors.initials: G
authors.lastname: Tan
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Fengyuan
authors.initials: F
authors.lastname: Shi
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Shiqiang
authors.initials: S
authors.lastname: Hao
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.|School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Zhao
authors.affiliation: Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Hang
authors.identifier: 0000-0002-1299-1150
authors.initials: H
authors.lastname: Chi
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Xiaomi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Ctirad
authors.initials: C
authors.lastname: Uher
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Wolverton
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Vinayak P
authors.initials: VP
authors.lastname: Dravid
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.|Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis