Enhanced Thermoelectric Properties of Cu3SbSe4 Compounds by Isovalent Bismuth Doping

Lijun Zhao,Haicheng Shao,Mingyuan Wang,Jian Yang,Yuan Zhu,Jiabin Hu,Neng Wan,Shahid Hussain,Guanjun Qiao,Guiwu Liu,Zhongqi Shi,Shuangying Lei

doi:10.1007/s10854-021-06403-6

Abstract

Cu3SbSe4, featuring its earth-abundant, cheap, nontoxic and environmentally friendly constituent elements, can be considered as a promising intermediate temperature thermoelectric (TE) material. Herein, a series of p-type Bi-doped Cu3Sb1−xBixSe4 (x = 0–0.04) samples were fabricated through melting and hot pressing process, and the effects of isovalent Bi-doping on their TE properties were comparatively investigated by experimental and computational methods. TEM analysis indicates that Bi-doped samples consist of Cu3SbSe4 and Cu2−xSe impurity phases, which is in good agreement with the results of XRD, SEM and XPS. For Bi-doped samples, the reduced electrical resistivity (ρ) caused by the optimized carrier concentrations and enhanced Seebeck coefficient derived from the densities of states near the Fermi level give rise to a high power factor of ~ 1000 µWm−1 K−2 at 673 K for the Cu3Sb0.985Bi0.015Se4 sample. Additionally, the multiscale defects of Cu3SbSe4-based materials involving point defects, nanoprecipitates, amorphous phases and grain boundaries can strongly scatter phonons to depress lattice thermal conductivity (κlat), resulting in a low κlat of ~ 0.53 Wm−1 K−1 and thermal conductivity (κtot) of ~ 0.62 Wm−1 K−1 at 673 K for the Cu3Sb0.98Bi0.02Se4 sample. As a consequence, a maximum ZT value ~ 0.95 at 673 K is obtained for the Cu3Sb0.985Bi0.015Se4 sample, which is ~ 1.9 times higher than that of pristine Cu3SbSe4. This work shows that isovalent heavy element doping is an effective strategy to optimize thermoelectric properties of copper-based chalcogenides.

Highlights

Thermoelectric (TE) materials, dealing with environmental protection and economic development, have gained great interest of research for waste energy recovery, temperature control and heat management in last two decades owing to the direct interconversion between heat and electricity power [1,2,3,4,5]
We report a high-performance Cu3SbSe4-based material via Bi-doping
It can be deduced that the addition of Bi is propitious to the precipitation of Cu2 − xSe phase, which is beneficial to decrease in lattice thermal conductivity

Summary

Introduction

Thermoelectric (TE) materials, dealing with environmental protection and economic development, have gained great interest of research for waste energy recovery, temperature control and heat management in last two decades owing to the direct interconversion between heat and electricity power [1,2,3,4,5]. The efficiency of a TE material is determined by the dimensionless thermoelectric figure of merit, ZT = S2T/ρκ, where S, ρ, T and κ presents the Seebeck coefficient, electrical resistivity, absolute temperature, total thermal conductivity (including lattice thermal conductivity κlat and electronic thermal conductivity κele), respectively [12, 13]. The exploitation of earth-abundant, cheap, nontoxic TE materials (more economical) is urgently in large-scale practical application of TE devices [7, 34]

Methods

Results

Conclusion