Thermoelectric Properties of Sb-S System Compounds from DFT Calculations.

Hailong Yang,Marie-Christine Record,Pascal Boulet

doi:10.3390/ma13214707

Abstract

By combining density functional theory, quantum theory of atoms in molecules and transport properties calculations, we evaluated the thermoelectric properties of Sb-S system compounds and shed light on their relationships with electronic structures. The results show that, for Sb2S3, the large density of states (DOS) variation induces a large Seebeck coefficient. Taking into account the long-range weak bonds distribution, Sb2S3 should exhibit low lattice thermal conductivity. Therefore, Sb2S3 is promising for thermoelectric applications. The insertion of Be atoms into the Sb2S3 interstitial sites demonstrates the electrical properties and Seebeck coefficient anisotropy and sheds light on the understanding of the role of quasi-one-dimensional structure in the electron transport. The large interstitial sites existing in SbS2 are at the origin of phonons anharmonicity which counteracts the thermal transport. The introduction of Zn and Ga atoms into these interstitial sites could result in an enhancement of all the thermoelectric properties.

Highlights

In a preceding paper [1], we performed a chemical bonding analysis on the ternary Cu-Sb-Se system compounds and showed that the weak interactions, either in local or whole structure, played an important role in lattice thermal conductivity
Since the crystal structure is related to the electronic structure and to the electronic transport path, the analysis of chemical bonds is a bridge between the structure and the thermoelectric properties
Due to its crystal structure made of one-dimensional (1D) ribbons of polymerized [Sb4 S6 ]n, the low-dimensional Sb2 S3 is of wide interest in various applications, such as in television cameras [44], microwave devices [45], switching devices, [46] various optoelectronic devices, [47,48,49], as well as photoelectric and thermoelectric cooling devices [50,51,52]

Summary

Introduction

In a preceding paper [1], we performed a chemical bonding analysis on the ternary Cu-Sb-Se system compounds and showed that the weak interactions, either in local or whole structure, played an important role in lattice thermal conductivity. There have been many attempts that tried to explore structure and properties using the concept of chemical bonds, such as the established models of covalent bonding [2], dielectric constants [3], partially ionic binding [4,5] and ionicity [6]. The complex correlation among physical interactions and bond properties makes the development of a general model very difficult. A commonly accepted concept is that the bonding information can be directly obtained from the charge density. The quantum theory of atoms in molecules (QTAIM) developed by

Methods

Results

Conclusion