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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]

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]

Lanthanum telluride (La 3- x Te 4) is one of the important candidates of thermoelectric (TE) materials working at high temperatures over 1000 K. However, the thermal stability and oxidation resistance of the TE materials become the crucial issue when they are working at so high temperatures. In this report, it is found that, although La 3- x Te 4 exhibits excellent thermal stability up to 1200 K under inert atmosphere, the existence of oxygen even in very low partial pressure causes serious oxidation and performance degradation at a temperature over 700 K. By introducing metallic nickel particles into La 2.74 Te 4 matrix forming La 2.74 Te 4 /Ni composites, the oxidation rate is greatly reduced both in air and low oxygen partial pressure (Po 2 = 10−3 MPa). The dense La 2 NiO 4 /Ni 2 Te 3 O 8 /NiO oxide composite layer formed during oxidation is in charge of "blocking" the diffusion of oxygen. Dispersing Ni particles gives indistinct influence on the thermoelectric properties leading to a good dimensionless thermoelectric figure of merit as 1.0 at 1273 K in the La 2.74 Te 4 /10 vol.% Ni composite. [Display omitted] [ABSTRACT FROM AUTHOR]

Thermoelectric (TE) fibers are more suitable than films for portable or wearable devices. Herein, 2–3 nm thick poly (3,4‐ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) layer‐coated tellurium nanowires (PC‐Te NWs) are in situ prepared by a hydrothermal method. Then a series of PEDOT: PSS/PC‐Te NWs composite fibers are prepared by wet spinning and post‐treatment. The nanolayer prevents the agglomeration of the Te NWs and makes the NWs and PEDOT:PSS matrix have good compatibility, which results in the PC‐Te NWs content to a high value of 70 wt% and the fibers still with flexibility. The high aspect ratio of the PC‐Te NWs and the stress from the inner wall of the needle during spinning make the NWs ordered align along the composite fiber. Due to the large content and orientational arrangement of the PC‐Te NWs, as well as effective post‐treatment, an optimized composite fiber shows a power factor of 385.4 µW m−1 K−2 at 300 K, which is ≈4.9 times as high as the highest value of previously reported PEDOT:PSS/Te NWs‐based composite fibers. In addition, the composite fiber has good flexibility. The flexible TE generators assembled have excellent output performance. This work provides an effective strategy for the preparation of high‐performance flexible TE composite fibers. [ABSTRACT FROM AUTHOR]

Thermoelectric transient pulse cooling can break through the limitations of thermoelectric material properties and achieve cooling performance beyond steady-state, which has great potential in active thermal management of high-power electronic devices. However, traditional control strategy for thermoelectric cooler (TEC) under steady cooling modes severely limits the widespread application of pulse cooling. This work focused on the key issue of precise temperature control under ultra-high thermal shock, and developed a novel control strategy composed of PID control, transient pulse control, and feed-forward control. By involving the thermoelectric transient pulse cooling effect, TEC can bear much high thermal load, and feed-forward control can further improve the temperature stability. As a result, the new strategy can bear extreme pulse thermal load as high as 4.59 times of the maximum cooling capacity of the TEC in steady-state within width of 20 ms, and the temperature fluctuation can be suppressed to 0.5 K from 7.58 K by using traditional control strategy based on maximum steady-state cooling capacity. This work demonstrates that the control strategy based on transient pulse cooling can greatly improve the capacity and response speed of thermoelectric cooling, providing important reference for precise temperature control of high-power electronic devices. • A novel control strategy was developed for the transient cooling mode in TEC. • Control strategy based on transient pulse effect realizes higher cooling capacity. • Feed-forward control can improve the temperature control precision. [ABSTRACT FROM AUTHOR]

Abstract: p-type Sn-doped CoSb3-based skutterudite compounds have been prepared using melting–quenching–annealing method and spark plasma sintering technique. Sn atoms in our samples are completely soluted on Sb-site with a fixed charge state and non-magnetic feature, providing a better choice to ascertain the effect of element doping at the [Co4Sb12] framework on the electrical and thermal transport properties in p-type skutterudites. Doping Sn at the framework introduces additional ionized impurity scattering to affect the electron transport greatly. Similar electrical transport properties between Ce0.2Co4Sb11.2Sn0.8 and Co4Sb11Sn0.6Te0.4 suggest that Ce fillers contribute little to the valence band edge. Filling Ce into the voids and doping Sn at the framework introduce additional phonon resonant and point defect scattering mechanisms, thereby reducing lattice thermal conductivity remarkably. Moreover, our data suggest that combining these two effects is more effective to suppress lattice thermal conductivity through scattering broad range of phonons with different frequencies. [ABSTRACT FROM AUTHOR]