Emerging homogeneous superlattices in CaTiO3 bulk thermoelectric materials

Jianbo Li; Yanxia Wang; Xue Jiang; Zhen Tian; Huijun Kang; Zongning Chen; Enyu Guo; Zhiqiang Cao; Tongmin Wang

doi:10.1039/d2mh01332k

Emerging homogeneous superlattices in CaTiO₃ bulk thermoelectric materials

Mater Horiz. 2023 Feb 6;10(2):454-465. doi: 10.1039/d2mh01332k.

Authors

Jianbo Li¹, Yanxia Wang², Xue Jiang², Zhen Tian¹, Huijun Kang^{1

3}, Zongning Chen^{1

3}, Enyu Guo^{1

3}, Zhiqiang Cao^{1

3}, Tongmin Wang^{1

3}

Affiliations

¹ Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China. kanghuijun@dlut.edu.cn.
² Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
³ Ningbo Institute of Dalian University of Technology, Ningbo 315000, China.

PMID: 36606474
DOI: 10.1039/d2mh01332k

Abstract

The thermal conductivity of superlattices is strongly reduced as compared to that of the parent materials due to phonon-scattering and thermal boundary resistances at the superlattice period interfaces. Herein, homogenous superlattices consisting of homogenous structural Ce_δCa_1-δTiO₃ and CaTi_1-δCe_δO₃ alternate layers were obtained through a variable-valence Ce doping, providing multi-quantum well interfaces between the alternate layers due to Ce-substitution at Ca and Ti sites, respectively. This material comprising these homogenous superlattices displayed a significantly reduced lattice thermal conductivity of 1.82 W m^-1 K^-1 and a record high zT value of 0.405 at 1031 K in CaTiO₃-based thermoelectric materials. This strategy of synthesizing homogeneous superlattices provides a cost advantage over heterogeneous superlattices prepared by the molecular beam epitaxy method and paves a route for preparing bulk superlattices with unique thermoelectric properties rooting in the quantum domain limiting effect.