Recent advances in non-Pb-based group-IV chalcogenides for environmentally-friendly thermoelectric materials

Abstract

Pb-based group-IV chalcogenides including PbTe and PbSe have been extensively studied as high performance thermoelectric materials during the past few decades. However, the toxicity of Pb inhibits their applications in vast fields due to the serious harm to the environment. Recently the Pb-free group-IV chalcogenides have become an extensive research subject as promising thermoelectric materials because of their unique thermal and electronic transport properties as well as the enviromentally friendly advantage. This paper briefly summarizes the recent research advances in Sn-, Ge-, and Sichalcogenides thermoelectrics, showing the unexceptionally high thermoelectric performance in SnSe single crystal, and the significant improvement in thermoelectric performance for those polycrystalline materials by successfully modulating the electronic and thermal transport through using some well-developed strategies including band engineering, nanostructuring and defect engineering. In addition, some important issues for future device applications, including N-type doping and mechanical and chemical stabilities of the new thermoelectrics, are also discussed.

Semiconductor glass with superior flexibility and high room temperature thermoelectric performance

“…The measured hardness of Ag 2 Te 0.6 S 0.4 is 19.5 kgf mm −1 , which is much smaller than those of the conventional TE materials (Fig. 1D) (7,16,17,22,23). In comparison with the previous reported Ag 2 S showing a record ductility among polycrystalline semiconductors (15), our Ag 2 Te 0.6 S 0.4 sample exhibits much better plastic deformation property, slightly higher bending property, comparable hardness, and lower but reasonably good compressibility.…”

“…(D) Vickers hardness. Typical materials are shown for comparison(8,16,17,22,23,(24)(25)(26)(27)(28)(29).…”

Isovalent substitution in metal chalcogenide materials for improving thermoelectric power generation – A critical review

“…Pristine SnSe has demonstrated a tremendous TE performance (zT ~ 2.6 at 923 K) [201] and has attracted considerable attention for high-temperature TE devices. This has uncovered and shown the great potential of non-lead-based group IV chalcogenides for TE devices due to their similar crystal structure to that of PbTe [202]. Like PbTe materials, SnSe undergoes a phase transition from a low-symmetry orthorhombic (Pnma space group) to a higher-symmetry orthorhombic (Cmcm space group) structure when the temperature approaches 750 K, responsible for the unique transport properties.…”

Grain size and structure distortion characterization of α-MgAgSb thermoelectric material by powder diffraction*

“…One of the main methods to improve ZT is the nanocrystallization synthetic technique resulting in κ lat suppression of phonon scattering from micro-nano scale boundaries and interfaces. [2][3][4][5] Poudel et al developed a nanostructuring approach which significantly improved the ZT value of the thermoelectric material BiSbTe. [3] The sample was synthesized by a two-step ball milling and hotpressing method.…”