title: Vacancy-induced dislocations within grains for high-performance PbSe thermoelectrics.
abstract: To minimize the lattice thermal conductivity in thermoelectrics, strategies typically focus on the scattering of low-frequency phonons by interfaces and high-frequency phonons by point defects. In addition, scattering of mid-frequency phonons by dense dislocations, localized at the grain boundaries, has been shown to reduce the lattice thermal conductivity and improve the thermoelectric performance. Here we propose a vacancy engineering strategy to create dense dislocations in the grains. In Pb1-xSb2x/3Se solid solutions, cation vacancies are intentionally introduced, where after thermal annealing the vacancies can annihilate through a number of mechanisms creating the desired dislocations homogeneously distributed within the grains. This leads to a lattice thermal conductivity as low as 0.4 Wm-1K-1and a high thermoelectric figure of merit, which can be explained by a dislocation scattering model. The vacancy engineering strategy used here should be equally applicable for solid solution thermoelectrics and provides a strategy for improving zT.
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China.
authors.forename: Binghui
authors.initials: B
authors.lastname: Ge
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China.
authors.forename: Siqi
authors.initials: S
authors.lastname: Lin
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China.
authors.forename: Jiawen
authors.initials: J
authors.lastname: Shen
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, China.
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, 3033 Cook Hall, Evanston, Illinois 60208 USA.
authors.forename: Riley
authors.initials: R
authors.lastname: Hanus
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, 3033 Cook Hall, Evanston, Illinois 60208 USA.
authors.forename: G Jeffrey
authors.initials: GJ
authors.lastname: Snyder
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Pei