The incorporation of carbon nanotubes (CNTs) within polymer hosts offers a great platform for the development of advanced thermoelectric (TE) composite materials. Over the years, several CNT/polymer composite formulations have been investigated on an effort to maximize the TE performance. Meanwhile, several studies focused on the decay dynamics of the charged excitons within CNTs itself and therefrom derived structures, aiming to investigate the lifetimes and the corresponding recombination processes of free charge carriers. The latter physical phenomena play a crucial role in the performance of various types of energy converting and scavenging materials. Nevertheless, up to this date, there is no systematic study on the combination of TE parameters and the critical charge carrier dynamics within CNT containing TE polymer composites. Herein, a variety of composites with single and hybrid CNT fillers based on polycarbonate (PC) and polyether ether ketone (PEEK) polymer matrices were prepared by melt-mixing in small scale. At the same loading, the addition of single fillers in PC results in higher Seebeck coefficients and similar conductivities when compared to the use of hybrid filler systems. In contrast, with hybrid filler systems in PEEK composites, higher power factors could be reached than in single filler composites. Moreover, the PC-based composites are studied using ultrafast laser time-resolved transient absorption spectroscopy (TAS), for the investigation of the exciton lifetimes and the physical origins of free charge carrier transport within the TE films. The findings of this study reveal interesting links between the TE parameters and the obtained charge carrier dynamics. Namely it is found that the Seebeck coefficient of the composites relates directly to the exciton lifetimes, whereas the volume conductivity is independent of the exciton lifetimes and is determined mainly by the average number and the mobility of the free charged electrons at the higher energy states.

We report a robust anomalous Nernst effect in Co2MnGa thin films in the thickness regime between 20 and 50 nm. The anomalous Nernst coefficient varied in the range of -2.0 to -3.0 µV/K at 300 K. We demonstrate that the anomalous Hall and Nernst coefficients exhibit similar behavior and fulfill the Mott relation. We simultaneously measure all four transport coefficients of the longitudinal resistivity, transversal resistivity, Seebeck coefficient, and anomalous Nernst coefficient. We connect the values of the measured and calculated Nernst conductivity by using the remaining three magneto-thermal transport coefficients, where the Mott relation is still valid. The intrinsic Berry curvature dominates the transport due to the relation between the longitudinal and transversal transport. Therefore, we conclude that the * a.thomas@ifw-dresden.de 2 Mott relationship is applicable to describe the magneto-thermoelectric transport in Weyl semimetal Co2MnGa as a function of film thickness.

Ultrathin 2D transition metal dichalcogenide (TMD) thin films have attracted much attention due to their very good electrical, optical, and electrochemical properties. Chemical vapor deposition (CVD) and atomic layer deposition (ALD), which is in some regards an enhanced version of CVD, are techniques that can provide exceptionally conformal large‐area coatings, even for complex surface geometries. Besides, these techniques include the transport of one or more precursor chemicals in the gas phase onto a substrate. Subsequently, a chemical reaction occurs, resulting in the deposition of a film of a solid material on the substrate. One of the advantageous aspects of chemical deposition methods, such as CVD and ALD, is the growth of thin films onto a variety of substrates as well as 3D structures. Because of their chemical approach, these techniques are well suited to synthesizing 2D materials (2DMs) with a low defect concentration. Furthermore, the scalability would allow industrial application, as opposed to, e.g., micromechanical cleavage. Here, the recent progress in 2D TMD thin films is reviewed and the current applications of these materials fabricated by CVD and ALD are surveyed.

We report the methods increasing both strength and ductility of aluminum alloys transformed from amorphous precursor. The mechanical properties of bulk samples produced by spark-plasma sintering (SPS) of amorphous Al-Ni-Co-Dy powders at temperatures above 673 K are significantly enhanced by in-situ crystallization of nano-scale intermetallic compounds during the SPS process. The spark plasma sintered Al84Ni7Co3Dy6 bulk specimens exhibit 1433 MPa compressive yield strength and 1773 MPa maximum strength together with 5.6% plastic strain, respectively. The addition of Dy enhances the thermal stability of primary fcc Al in the amorphous Al-TM -RE alloy. The precipitation of intermetallic phases by crystallization of the remaining amorphous matrix plays important role to restrict the growth of the fcc Al phase and contributes to the improvement of the mechanical properties. Such fully crystalline nano- or ultrafine-scale Al-Ni-Co-Dy systems are considered promising for industrial application because their superior mechanical properties in terms of a combination of very high room temperature strength combined with good ductility.

Micro‐thermoelectric (TE) devices have a great potential for future applications in the field of energy harvesting to power autonomous sensors. Bi2Te3 sputtered at elevated substrate temperatures exhibits a high figure of merit (ZT) suitable for the fabrication of micro‐TE devices. However, a lift‐off process that does not allow higher substrate temperatures is often used, and although Bi2Te3 is a well‐studied TE material, it lacks full ZT characterization of thin films. Herein, the full TE characterization of sputtered Bi2Te3 thin films is presented, including the charge carrier concentration and mobility, which are deposited at room temperature and postannealed between 150 and 300 °C. The influence of the annealing time and temperature is investigated on a 90 nm‐thick Bi2Te3 film. A maximum ZT of 0.20 is found, which results from the increasing crystallinity and reduction of point defects. To investigate the thickness dependency, Bi2Te3 films with thicknesses of 90, 170, 350, and 470 nm are annealed at 250 °C. A maximum ZT value of 0.26 is observed for the 350 nm Bi2Te3 film. Furthermore, it can be shown that with increasing film thickness, the annealing time has to be increased to maximize ZT.

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Ultrathin 2D transition metal dichalcogenide (TMD) thin films have attracted much attention due to their very good electrical, optical, and electrochemical properties. Here, the recent progress in 2D TMD thin films is reviewed and the current applications of these materials fabricated by chemical vapor deposition and atomic layer deposition are surveyed. More details are in article number https://doi.org/10.1002/admi.201800688 by Gyu‐Hyeon Park, Kornelius Nielsch, and Andy Thomas.

Using datasets from several sources, a list of more than 450 materials is generated and related them with their thermoelectric properties. This is obtained by generating a set of features using only the molecular formula. Subsequently, a machine learning algorithm classifies the materials in specific, binary classes, for example, possessing high or low Seebeck coefficients or electrical conductivity. After adjusting the threshold values and grouping the materials into clusters, the thermoelectric performance of more than 25k materials is predicted. Finally, the results are filtered to obtain only the sustainable materials, that is, neither toxic nor critical, (ideally) inexpensive, and isotropic with regard to their transport properties to simplify the preparation procedure.