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Metallic barrier layer is a key component in thermoelectric (TE) devices, but it is rarely investigated for the recently discovered inorganic ductile TE materials. In this work, we demonstrate that tungsten (W) is the excellent metallic barrier layer for Ag2S1−xSex ductile thermoelectric materials. The phase composition, microstructure, adhesive strength, and interfacial contact resistivity (ρC) of the W/Ag2S1−xSex joint have been systematically investigated. The sputtered W film has high adhesive strength and little interdiffusion/reaction with Ag2S1−xSex. The ρC decreases with increasing the Se content, which can be understood by the Thermionic-field Emission model. This work would guide the development of high-performance flexible TE devices based on ductile TE materials. [ABSTRACT FROM AUTHOR]

In this work, we report the ternary Cu-based chalcogenide, Cu2TiTe3, as a promising thermoelectric material in middle-temperature range. The bonding interaction between Te p and Ti d states is observed in the Ti–Te octahedron, which drives the side bands up converging with Γ band, yielding a high valence band degeneracy of 5. A high electronic quality factor of 2.2 μW cm−1 K−2 and a decent power factor of 7.5 μW cm−1 K−2 at 300 K are achieved for Cu2TiTe3. Likewise, Cu2TiTe3 demonstrates low lattice thermal conductivity throughout the measured temperature range, which is attributed to the low frequency vibration related to the global motion of Ti–Te–Cu clusters. Finally, a maximum figure-of-merit of 0.38 was obtained for Cu2TiTe3 at 600 K. [ABSTRACT FROM AUTHOR]

As the pseudo-binary alloys between GeTe and Sb2Te3, GeSbTe-based compounds are promising thermoelectric materials. Although Ge2Sb2Te5 and GeSb2Te4 have widely been studied, the thermoelectric properties of GeSb4Te7 have not been well understood yet. In this work, we design a series of GeSb4-xBixTe7 solid solutions and systematically study the variation in the crystal structure, electrical, and thermal transport properties. Alloying Bi effectively reduces the carrier concentration and, thus, enhances the Seebeck coefficient. Meanwhile, the thermal conductivity is greatly reduced via large mass fluctuations. A maximum zT of 0.69 at 550 K and an average zT value of 0.52 between 300 and 700 K have been achieved for GeSb1.5Bi2.5Te7. These findings will promote the understanding and development of GeSbTe-based thermoelectric materials. [ABSTRACT FROM AUTHOR]

Recently, a deformable and ductile inorganic semiconductor Ag2S has attracted intense attention due to its potential application in self-powered wearable and hetero-shaped electronics. However, the thermoelectric figure of merit (zT) of Ag2S is greatly limited by its extremely low carrier concentration. In this study, via doping I into Ag2S-based materials, we tune the carrier concentration into the optimal range as well as suppressing the lattice thermal conductivity. A maximum zT value of 0.26 is achieved for Ag2S0.7Se0.295I0.005 at 300 K, about three times higher than the matrix compound. More importantly, doping I has little effect on the ductility and deformability of Ag2S-based materials. Our study shows that I-doped Ag2S-based materials are good candidates for developing flexible thermoelectric technologies. [ABSTRACT FROM AUTHOR]