Intrinsically low thermal conductivity from a quasi-one-dimensional crystal structure and enhanced electrical conductivity network via Pb doping in SbCrSe3

Dingfeng Yang,Xiaodong Han,Wujie Qiu,Guoyu Wang,Tao Yang,Wei Yao,Lijie Guo,Ctirad Uher,Yanci Yan,Xiaoyuan Zhou,Xu Lu

doi:10.1038/am.2017.77

Abstract

The development of new routes for the production of thermoelectric materials with low-cost and high-performance characteristics has been one of the long-term strategies for saving and harvesting thermal energy. Herein, we report a new approach for improving thermoelectric properties by employing the intrinsically low thermal conductivity of a quasi-one-dimensional (quasi-1D) crystal structure and optimizing the power factor with aliovalent ion doping. As an example, we demonstrated that SbCrSe3, in which two parallel chains of CrSe6 octahedra are linked by antimony atoms, possesses a quasi-1D property that resulted in an ultra-low thermal conductivity of 0.56 W m−1 K−1 at 900 K. After maximizing the power factor by Pb doping, the peak ZT value of the optimized Pb-doped sample reached 0.46 at 900 K, which is an enhancement of 24 times that of the parent SbCrSe3 structure. The mechanisms that lead to low thermal conductivity derive from anharmonic phonons with the presence of the lone-pair electrons of Sb atoms and weak bonds between the CrSe6 double chains. These results shed new light on the design of new and high-performance thermoelectric materials.

Highlights

The design and engineering of novel thermoelectric materials has been one of the most urgent demands for thermal energy saving and harvesting
We demonstrated that SbCrSe3, in which two parallel chains of CrSe6 octahedra are linked by antimony atoms, possesses a quasi-1D property that resulted in an ultra-low thermal conductivity of 0.56 W m − 1 K − 1 at 900 K
For the first time, we report on the synthesis, high-temperature thermoelectric properties and the calculated electronic structure of the quasi-1D SbCrSe3 compound, which shows an intrinsically low thermal conductivity

Summary

Introduction

The design and engineering of novel thermoelectric materials has been one of the most urgent demands for thermal energy saving and harvesting. The investigation of the chemical bonding, crystal structures and corresponding lattice dynamics is helpful in understanding phonon transport and the design of materials with an intrinsically low lattice thermal conductivity and high thermoelectric performance.

Results

Conclusion