Charge and phonon transport in PbTe-based thermoelectric materials

Abstract

PbTe is a typical intermediate-temperature thermoelectric material, which has undergone extensive developments and achieved excellent high thermoelectric performance. In this perspective we summarized several strategies that were successfully applied in PbTe-based thermoelectric materials through manipulating charge and phonon transports, such as optimizing carrier density to tune Fermi level, tailoring band structure to enhance effective mass, and designing all-scale hierarchical architectures to suppress phonon propagation. Meanwhile, due to the different features of conduction and valence bands, we separately introduced the approaches to enhance performance of p-type and n-type PbTe. In p-type PbTe, the strategies of band convergence, band alignment and density of state (DOS) distortion are more effective to achieve high electrical transport properties. By contrast, flattening conduction bands and introducing deep impurity level are more suitable for n-type PbTe. Lastly, several potential strategies were proposed to further improve the thermoelectric performance of PbTe-based materials, which might be extended to other thermoelectric systems.

Energy Filtering of Charge Carriers: Current Trends, Challenges, and Prospects for Thermoelectric Materials

“…Single phase TE materials are widely studied, among them are PbTe, PbSe,7b Bi 2 Te 3 , skutterudites, clathrates, and half‐Heusler (HH)6a alloys typically exhibit zT values around 1 through simple doping, whereas further improvement in zT could be attained by adopting the aforementioned strategies. The scientific community has faced a few challenging problems, such as reproducibility of stoichiometry,4a control over properties for a wide temperature range and, most importantly, tuning both S and σ simultaneously 7b.…”

Chalcogenide Thermoelectrics Empowered by an Unconventional Bonding Mechanism

“…First, most of them can easily be doped into p‐type or n‐type, which is critical for the assembly of thermoelectric devices . Second, they consist of heavy elements and soft chemical bonds, resulting in low thermal conductivity . Third, they possess a variety of structures, providing a good platform for manipulating the thermoelectric performance.…”

“…Some rare‐earth chalcogenides can even be used above 1000 K due to their high thermal stability, such as La 3− x Te 4 which exhibits a maximum zT of ≈1.1 at 1275 K . More comprehensive discussions of the thermoelectric properties of chalcogenide compounds can be found elsewhere …”

High‐Performance GeTe‐Based Thermoelectrics: from Materials to Devices

“…[ 26–30 ] High‐performance thermoelectric materials require high S , high σ, and low κ. [ 24,31–34 ] However, due to the strong coupling between these parameters, the optimization of thermal/electrical transport properties is the key for ZT enhancement. [ 35–40 ] The performance of thermoelectric materials can be enhanced from the two aspects: 1) optimization of electrical transportation performance and 2) minimization of thermal transport properties.…”

“…n p can be optimized by aliovalent substitutions [ 85 ] and Ge vacancy engineering. [ 85,86 ] Tuning the band structure can be realized by bandgap engineering, [ 32 ] band degeneracy engineering, [ 87 ] and resonant state engineering. [ 88 ] Reducing κ l can be achieved by strengthening the phonon–phonon scattering (reducing v ) [ 73 ] and introducing multiple phonon scattering centers (reducing relaxation time, τ).…”