Controlled Phonon Transport via Chemical Bond Stretching and Defect Engineering: The Case Study of Filled β-Mn-Type Phases.

Controlling the elastic properties of the material could become a powerful tool for tuning the thermal transport in solids. Nevertheless, the impact of the crystal structure, chemical bonding, and elastic properties on the lattice thermal conductivity remains to be elucidated. This is a pivotal issue for the advancement of thermoelectric (TE) materials.

Achieving high thermoelectric conversion efficiency in BiTe-based stepwise legs through bandgap tuning and chemical potential engineering.

In this study, we show that the energy conversion efficiency in thermoelectric (TE) devices can be effectively improved through simultaneous optimization of carrier concentration, bandgap tuning, and fabrication of stepwise legs. - and -type BiTe-based materials were selected as examples for testing the proposed approach. At first, the Boltzmann transport theory was employed to predict the optimal temperature-dependent carrier concentration for high thermoelectric performance over a broad temperature range.

Structure Evolution and Bonding Inhomogeneity toward High Thermoelectric Performance in CuCoSnSSe Materials.

Lightweight diamond-like structure (DLS) materials are excellent candidates for thermoelectric (TE) applications due to their low costs, eco-friendly nature, and property stability. The main obstacles restricting the energy-conversion performance by the lightweight DLS materials are high lattice thermal conductivity and relatively low carrier mobility. By investigating the anion substitution effect on the structural, microstructural, electronic, and thermal properties of CuCoSnSSe, we show that the simultaneous enhancement of the crystal symmetry and bonding inhomogeneity engineering are effective approaches to enhance the TE performance in lightweight DLS materials.

Lone-Pair-Like Interaction and Bonding Inhomogeneity Induce Ultralow Lattice Thermal Conductivity in Filled β-Manganese-Type Phases.

Finding a way to interlink heat transport with the crystal structure and order/disorder phenomena is crucial for designing materials with ultralow lattice thermal conductivity. Here, we revisit the crystal structure and explore the thermoelectric properties of several compounds from the family of the filled β-Mn-type phases GaTe ( = Pb, Sn, Ca, Na, Na + Ag). The strongly disturbed thermal transport observed in the investigated materials originates from a three-dimensional Te-Ga network with lone-pair-like interactions, which results in large variations of the Ga-Te and -Te interatomic distances and substantial anharmonic effects.

Ultralow Lattice Thermal Conductivity and Improved Thermoelectric Performance in Cl-Doped BiTeSe Alloys.

BiTe-based alloys are the main materials for the construction of low- and medium-temperature thermoelectric modules. In this work, the microstructure and thermoelectric properties of Cl-doped BiTeSe alloys were systematically investigated considering the high anisotropy inherent in these materials. The prepared samples have a highly oriented microstructure morphology, which results in very different thermal transport properties in two pressing directions.