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The contact resistivity originating from the metal–semiconductor interface is a crucial factor for conversion efficiency of thermoelectric films devices. Due to anisotropic nature of state‐of‐art Bi2Te3 films, the contact resistivity also needs to match with the different orientations in/out‐plane film configurations. Here, a series of bismuth telluride (Bi2Te3) films with different orientations are deposited, and the contact resistivity between Ti/Cr/Cu and Bi2Te3‐based films is studied in detail. The increased (00l) orientation can effectively reduce the contact resistivity mainly due to the enhanced Tunneling effect. Finally, a low contact resistivity of 0.84 µΩ cm2 is observed in highly (00l)‐orientated Bi2Te3 film in contact with Cr. This work provides an effective method to control contact resistivity by adjusting the orientation of film, and also provides guidance on how to further improve the performance of thin film‐TEDs with different configurations. [ABSTRACT FROM AUTHOR]

Bi1−xSbx crystal is one of the best n-type thermoelectric materials below 200 K, but its weak mechanical strength hinders practical applications for deep refrigeration. Herein, we adopted the mechanical enhancement method of hot extrusion to investigate the comprehensive mechanical and thermoelectric properties of Bi0.905Sb0.095. It revealed that reducing the grain size of the matrix and increasing the extrusion ratio can improve the gain size uniformity and mechanical properties. Meanwhile, the thermoelectric performance depends on the texture, grain size, and local composition. The extruded sample prepared by ingot with the high extrusion ratio of 9:1 generated uniform small grains, which resulted in the high bending strength of Bi1−xSbx~130 Mpa and a high power factor of ~68 μW·cm−1·K−2@173 K, as well as the relatively high figure of merit of 0.25@173K. This work highlights the importance of the uniform distribution of the grain size and the compositions for Bi1−xSbx, as well as the required universal key parameter for the hot extrusion method. [ABSTRACT FROM AUTHOR]

La3Te4-based rare-earth telluride is a kind of n-type high-temperature thermoelectric (TE) material with an operational temperature of up to 1273 K, which is a promising candidate for thermoelectric generators. In this work, the Sm substitution in La3−xSmxTe4/Ni composites is reported. The electrical transport property of La3−xSmxTe4 is modified by reducing carrier concentration due to the substitution of Sm2+ for La3+. The electric thermal conductivity decreases by 90% due to carrier concentration reduction, which mainly contributes to a reduction in total thermal conductivity. Lattice thermal conductivity also decreases by point-defect scattering by Sm doping. Meanwhile, based on our previous study, compositing nickel improves the thermal stability of the La3 − xSmxTe4 matrix. Finally, combined with carrier concentration optimization and the decreased thermal conductivity, a maximum zT of 1.1 at 1273 K and an average zTave value of 0.8 over 600 K–1273 K were achieved in La2.315Sm0.685Te4/10 vol.% Ni composite, which is among the highest TE performance reported in La3Te4 compounds. [ABSTRACT FROM AUTHOR]

Abstract: Ab-initio calculations of the resonant modes and frequencies for a number of possible fillers in p-type RFe3CoSb12 and RFe4Sb12 were carried out. The results indicate that, although the exact values of fillers’ resonant frequencies in p-type skutterudites are somewhat different from those in n-type Co-based skutterudites, the Einstein-like resonant modes of the fillers are similar to those in n-type materials. Experimentally, several pairs of the fillers were selected and double-filled p-type skutterudite compounds RxMy Fe3CoSb12 (R, M = Ba, Ce, Nd, and Yb) were successfully synthesized. The reduction in the lattice thermal conductivity was realized by extending the range of resonant frequencies. As a result, enhanced ZT values above unity were achieved in these double-filled p-type skutterudites. [Copyright &y& Elsevier]