Combined high performance of self-propagating synthesized materials and topological structures optimization, half-Heusler single-stage module and half-Heusler/Bi ₂ Te ₃ segmented module attained record-high conversion efficiencies of 9.6% and 12.4%.

Although the CoSb₃-based skutterudite thermoelectric devices have been highly expected for wide uses such as waste heat recovery and space power supply, the limited long-term service stability majorly determined by the degradation of electrode interface obstructs its applications. Here, we built up an effective criterion for screening barrier layer based on the combination of negative interfacial reaction energy and high activation energy barrier of Sb migration through the formed interfacial reaction layer. Accordingly, we predicted niobium as a promising barrier layer. The experimental results show the skutterudite/Nb joint has the slowest interfacial reaction layer growth rate and smallest interfacial electrical resistivity. The fabricated 8-pair skutterudite module using Nb as barrier layer achieves a recorded conversion efficiency of 10.2% at hot-side temperature of 872 K and shows excellent stability during long-time aging. This simple criterion provides an effective guidance on screening barrier layer with bonding-blocking-conducting synergetic functions for thermoelectric device integration.

Entropy engineering is one of the powerful approaches to suppress phase transitions. GeTe has a very high thermoelectric performance at relatively high temperatures, but the low structure symmetry and phase transition in the low temperature range limits its performance stability for power generation applications. Therefore, the optimized electrical transport properties of GeTe in a low temperature range are expected for improving the structural symmetry via suppressing phase transition. Herein, the phase transition temperature for GeTe was successfully decreased by introducing high entropy via continuously multiple doping; the phase transition temperature is correspondingly reduced from 660 K to 523 K. The Seebeck coefficient was enhanced by the improved structural symmetry through enhancing band effective mass while the carrier concentration is maintained in an optimum range. A record-high power factor of ∼23 μW cm⁻¹ K⁻² was obtained at 300 K in the highest entropy sample. We found that the increased configurational entropy obtained by continuous, multiple doping produces short-range disordered microstructures, which lead to an ultralow lattice thermal conductivity of ∼0.4 W m⁻¹ K⁻¹. Combining the record high power factor and low thermal conductivity, a maximum ZT value of ∼2.1 at 800 K was achieved for the highest entropy species Ge_0.84In_0.01Pb_0.1Sb_0.05Te_0.997I_0.003. This study provides an effective path to enhance thermoelectric performances via introducing entropy engineering.

Unsatisfied electrode bonding in half-Heusler devices renders thermal damage and large efficiency loss, which limits their practical service at high temperatures. Here, we develop a thermodynamic strategy to screen barrier layer elements. Theoretically, we found that the interface between VIIB elements and half-Heuslers possesses near-zero interfacial reaction energy and large atomic diffusion barrier. Experimentally, such an interphase proves to be the atomic direct bonding and has high thermal stability at 1073 K, leading to ideal ohmic contact. Such thermally inert and ohmic contact interface enable modules stably to work at elevated temperature up to 1100 K, which releases the peak performance of half-Heuslers and in turn boosts the energy conversion efficiencies to the records of 11.1% and 13.3% for half-Heusler single-stage and half-Heusler/Bi₂Te₃ segmented modules. This design strategy provides a feasible solution for the high-temperature half-Heusler generators and gives enlightenment for other package interconnection design of electronic devices.

A maximum ZT of 1.25 at 400 K and an average ZT value of approximately 1.03 between 300 and 600 K were achieved in Ag_0.002Bi_0.5Sb_1.498Te₃ by successfully suppressing the intrinsic excitation.

Film-thermoelectric cooling devices are expected to provide a promising active thermal management solution with the continues increase of the power density of integrated circuit chips and other electronic devices. However, because the microstructure-related performance of thermoelectric films has not been perfectly matched with the device configuration, the potential of planar devices on chip heat dissipation has still not been fully exploited. Here, by liquid Te assistant growth method, highly (00 l) orientated Bi₂Te₃-based films which is comparable to single crystals are obtained in polycrystal films in this work. The high mobility stem from high orientation and low lattice thermal conductivity resulting from excess Te induced staggered stacking faults leads to high in-plane zT values ~1.53 and ~1.10 for P-type Bi_0.4Sb_1.6Te₃ and N-type Bi₂Te₃ films, respectively. The planar devices basing on the geometrically designed high orientation films produce a remarkable temperature reduction of ~8.2 K in the hot spot elimination experiment, demonstrating the great benefit of Te assistant growth method for oriented planar Bi₂Te₃ films and planar devices devices design, and also bring great enlightenment to the next generation active thermal management for integrated circuits.